TY - CONF A1 - Roveda, Ilaria A1 - Serrano Munoz, Itziar A1 - Madia, Mauro T1 - Investigation of residual stresses and microstructure effects on the fatigue behaviour of a L-PBF AlSi10Mg alloy N2 - Laser Powder Bed Fusion (L-PBF) allow the fabrication of lightweight near net shape AlSi10Mg components attractive to the aerospace, automotive, biomedical and military industries. During the build-up process, high cooling rates occur. Thus, L-PBF AlSi10Mg alloys exhibit a Si-nanostructure in the as-built condition, which leads to superior mechanical properties compared to conventional cast materials. At the same time, such high thermal gradients generally involve a deleterious residual stress (RS) state that needs to be assessed during the design process, before placing a component in service. To this purpose post-process heat treatments are commonly performed to relieve detrimental RS. In this contribution two low-temperature stress-relief heat treatments (SRHT) are studied and compared with the as-built state: a SRHT at 265°C for 1 hour and a SRHT at 300°C for 2 hours. At these temperatures microstructural changes occur. In the as-built state, Si atoms are supersaturated in the α-aluminium matrix, which is enveloped by a eutectic Si-network. At 265°C the Si precipitation from the matrix to the pre-existing network is triggered. Thereafter, above 295°C the fragmentation and spheroidization of the Si branches takes place, presumably by Al–Si interdiffusion. After 2 hours the original eutectic network is completely replaced by uniformly distributed blocky particles. The effect of the heat and the microstructure modification on the RS state and the fatigue properties is investigated. Energy dispersive x-ray and neutron diffraction are combined to investigate the near-surface and bulk RS state of a L-PBF AlSi10Mg material. Differences in the endurance limit are evaluated experimentally by high cycle fatigue (HCF) tests and cyclic R-curve determination. T2 - 43rd Materials Mechanics Seminar CY - Sani, Chalkidiki, Greece DA - 05.06.2022 KW - AlSi10Mg KW - Fatigue KW - Neutron diffraction KW - X-ray diffraction PY - 2022 AN - OPUS4-55090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fernádez-Canteli, A. A1 - Castillo, E. A1 - Blasón, Sergio A1 - Correia, J. A. F. O. A1 - de Jesus, A. M. P. T1 - Generalization of the Weibull probabilistic compatible model to assess fatigue data into three domains: LCF, HCF and VHCF N2 - n this work, three classes of fatigue models are reviewed according to the fatigue regimes commonly considered in the current components design. Particular attention is devoted to the so-called Class III fatigue models, covering the three fatigue regimes, namely, LCF, HCF and VHCF. The applicability and limitations of the pro-posed analytical sigmoidal solutions are discussed from the viewpoint of practical design. The compatible Weibull S-N model by Castillo and Canteli is revisited and improved by considering a new reference parameter GP = E⋅σM ⋅(dε/dσ)|M as the driving force alternative to the conventional stress range. In this way, the requirement, σM ≤ σu, according to the real experimental conditions, is fulfilled and the parametric limit number of cycles, N0, recovers its meaning. The probabilistic definition of the model on the HCF and VHCF regimes is maintained and extended to the LCF regime. The strain gradients may be calculated from the monotonic or cyclic stress–strain curve of the material although a direct derivation from the hysteresis loop is recommended. Some Class III fatigue models from the literature and another one improved by the authors are applied to the assessment of one experimental campaign under different stress ratios conditions and the results compared accordingly. Finally, the new probabilistic GP-N field is evaluated. The results confirm the practical confluence of the stress- and the strain-based approaches into a single and advantageous unified methodology. KW - LCF region KW - S-N probabilistic field KW - Energetic reference parameter PY - 2022 U6 - https://doi.org/10.1016/j.ijfatigue.2022.106771 SN - 0142-1123 VL - 159 SP - 1 EP - 18 PB - Elsevier Ltd. AN - OPUS4-55235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fernádez-Canteli, A. A1 - Castillo, E. A1 - Blasón, Sergio T1 - A methodology for phenomenological analysis of cumulative damage processes. Application to fatigue and fracture phenomena N2 - Sample functions, i.e., stochastic process realizations, are used to define cumulative damage phenomena which end into an observable terminal state or failure. The complexity inherent to such phenomena justifies the use of phenomenological models associated with the evolution of a physical magnitude feasible to be monitored during the test. Sample functions representing the damage evolution may be identified, once normalized to the interval [0,1], with cumulative distribution functions (cdfs), generally, of the generalized extreme value (GEV) family. Though usually only a fraction of the whole damage evolution, according to the specific problem handled, is available from the test record, the phenomenological models proposed allow the whole damage process to be recovered. In this way, down- and upwards extrapolations of the whole damage process beyond the scope of the experimental program are provided as a fundamental tool for failure prediction in the practical design. The proposed methodology is detailed and its utility and generality confirmed by its successive application to representative well-known problems in fatigue and fracture characterization. The excellent fittings, the physical interpretation of the model parameters and the good expectations to achieve a complete probabilistic analysis of these phenomena justify the interest of the proposed phenomenological approach with possible applications to other cumulative damage processes. KW - Bayesian technique KW - Sample random results KW - Stochastic sample functions KW - Probabilistic assessment PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-552371 SN - 0142-1123 VL - 150 SP - 106311 PB - Elsevier Ltd. AN - OPUS4-55237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García-González, M. A1 - González-González, I. A1 - García-García, I. A1 - Blasón-González, Sergio A1 - Lamela-Rey, M. J. A1 - Fernández-Canteli, A. A1 - Álvarez-Arenal, A. T1 - Effect of abutment finish lines on the mechanical behavior and marginal fit of screw-retained implant crowns: An in vitro study N2 - Statement of problem The design of the implant-abutment connection has been widely researched, but the impact of different crown-abutment geometries remains unclear. Purpose The purpose of this in vitro study was to evaluate the effect of different crown-abutment margin geometries on the mechanical behavior and fit of screw-retained implant-supported single-crown restorations by using mechanical static and fatigue tests and mastication simulation. Material and methods A total of 45 cobalt-chromium premolar-shaped metal frameworks were fabricated for single-unit implant-supported screw-retained restorations on stock abutments and internal hexagon Ø4.25×11-mm cylindrical implants. They were divided into 3 groups according to margin geometry: S, shoulder; C, chamfer; and F, feather-edge. Three static load until fracture and 24 dynamic load tests were performed by using the International Organization for Standardization 14801:2016 standard (ISO 14801:2016) (number of cycles limit: 5×106 cycles, frequency: 6 Hz). The ProFatigue software program was used to optimize the procedure (S, n=12 specimens; C, n=7 specimens; and F, n=5 specimens). Six additional specimens from each group were subjected to a mastication simulation (limit number of cycles: 1×106 cycles, cyclic loading from Pmin=30 N to Pmax=300 N, frequency: 6 Hz). Results from the fatigue tests were reported descriptively, and the Fisher exact test was used to analyze the difference in failure modes. Data from maximum misfit were evaluated by photogrammetry and statistically analyzed with the Anderson-Darling test and the Kruskal-Wallis and Dunn multiple comparison tests (α=.05). Results The fatigue limit was 456 N for group S, 512 N for group C, and 514 N for group F. The mean ±standard deviation misfit was 2.6 ±0.1 μm for group S, 3.8 ±1.1 μm for group C, and 3.6 ±0.8 μm for group F. Differences in misfit between groups S and C and between groups S and F were statistically significant (P<.05). Conclusions Crown-abutment connections with chamfer and feather-edge margins showed better mechanical behavior, while shoulder margin exhibited better fit. However, high levels of fit were achieved for all the evaluated geometries. KW - Photogrammetry KW - Implant-supported prostheses KW - Crown-abutment connection KW - Margin design KW - Static load KW - Dynamic load KW - Misfit PY - 2022 U6 - https://doi.org/10.1016/j.prosdent.2021.08.028 SN - 0022-3913 VL - 127 IS - 2 SP - 318.e1 EP - 318.e10 PB - Elsevier AN - OPUS4-55238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blasón, Sergio A1 - Fernández-Canteli, A. A1 - Poveda, E. A1 - Ruiz, G. A1 - Yu, R. C. A1 - Castillo, E. T1 - Damage evolution and probabilistic strain-lifetime assessment of plain and fiber-reinforced concrete under compressive fatigue loading: Dual and integral phenomenological model N2 - A phenomenological approach is proposed to describe and predict the random behaviour of the total strain in plain and fiber concrete under compressive fatigue loading. Twofold viewpoints are considered in the assessment of the fatigue damage process. The first one, acknowledged as the stochastic cumulative damage evolution in terms of the number of applied cycles is represented by a sample function, physically identified with the total specimen strain caused by matrix microcracking. The second one is ascribed to the intrinsic scatter of the total lifetime referred to as the prefixed ultimate fatigue strain limit state (not necessarily failure). The sample function, once normalized to the total fatigue lifetime, is identified as a cumulative distribution function (cdf) of the generalized extreme value (GEV) family, particularly as Weibull distribution. Besides the reliable probabilistic lifetime prediction for the material under compressive fatigue, the approach allows fatigue tests to be prematurely interrupted while the remaining evolution of the ε-N curve up to failure is fully restored from the fragment recorded. In this way, a remarkable time and cost reduction of the experimental program is achieved without detriment of data reliability. KW - Prematurely interrupted tests KW - Fatigue damage KW - Cyclic creep curve KW - Lifetime normalization KW - Probabilistic lifetime prediction PY - 2022 U6 - https://doi.org/10.1016/j.ijfatigue.2022.106739 SN - 0142-1123 VL - 158 SP - 1 EP - 20 PB - Elsevier Ltd. AN - OPUS4-55239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blasón Gonzalez, Sergio A1 - Chaudry, M. A1 - Elorriaga, A. A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Llavori, I. A1 - Hilgenberg, Kai T1 - Design methodology of vessel produced by L PBF stainless steel using representative specimens N2 - This work presents the preliminary results of an ongoing project with a double objective: on the one hand, the characterisation of the mechanical properties against fatigue damage of an additively manufactured 316 stainless steel produced by laser powder bed-based (L-PBF) technology; on the other hand, the implementation of numerical simulation techniques able to predict the mechanical behaviour of the material in order to optimise and reduce the design costs of vessels used in the chemical sector. The current state of the work developed in this research framework allows showing the first batch of experimental results of crack propagation rate (FCGR) and high cycle fatigue (HCF) tests. The geometry of the vessels studied presents three clearly differentiated regions, either in terms of thickness (11-15 mm) or concerning the inclination of the walls to the direction of manufacturing (0º - 45º). The experimental campaign carried out so far allows identifying the differences in behaviour when comparing different extraction locations around the vessel. This is due to the variations in thermal cycles that the deposited material undergoes during the manufacturing process. Therefore, this causes variations in the microstructure which lead to changes in the response of the material. In this work, these differences are analysed qualitatively and quantitatively from the results of FCGR and HCF, thus allowing to locate the regions with the highest risk in terms of structural integrity against fatigue. This preliminary phase together with the numerical simulation of the additive manufacturing process are key to achieving a reliable description and modelling of the material. The latter will make it possible to address the priority aim of this project, involving the manufacture of independent samples whose properties are representative of the original material extracted from the reference vessels. It is, therefore, a comprehensive methodology for the design of additively manufactured components based on the localised fatigue mechanical properties of representative specimens. T2 - ECF23, European Conference on Fracture 2022 CY - Funchal, Portugal DA - 27.06.2022 KW - Additive manufacturing KW - Steel 316L KW - Fracture Mechanics PY - 2022 AN - OPUS4-55240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blasón Gonzalez, Sergio A1 - Chaudry, M. A1 - Elorriaga, A. A1 - Madia, Mauro A1 - Llavori, I. A1 - Hilgenberg, Kai T1 - Diseño de componentes fabricados aditivamente basado en propiedades locales del material T1 - Design of additively manufactured components based on locally representative material fatigue properties N2 - La tecnología de fabricación aditiva (AM) continúan progresando y permitiendo alcanzar diseños cada vez más complejos y optimizados. La industria química es uno de los sectores donde componentes AM han adquirido un gran interés. La falta hasta la fecha de una directiva europea que regule la inspección, certificación y aceptación de equipos sometidos a presión hace necesario progresar en esta línea. El objetivo que se persigue en este trabajo es el de desarrollar una metodología de diseño sobre componentes fabricados aditivamente basada en la estimación de vida a fatiga de las zonas más susceptibles de sufrir dicho tipo de fallo. El estudio comprende diversas facetas de análisis, simulaciones numéricas, análisis de la microestructura del material y una extensa campaña experimental. La evaluación de la integridad estructural se realiza aplicando mecánica de fractura. La historia térmica a lo largo del proceso de fabricación determina la microestructura del componente en cada región y, por ende, influye en las propiedades mecánicas en cada una. Se presentan los resultados preliminares de un proyecto de investigación en curso dirigido a la caracterización de propiedades mecánicas en recipientes de presión producidos por fusión láser en lecho de polvo (L-PBF, por sus siglas en inglés) de acero inoxidable 316L. Se detallan los resultados preliminares en términos de velocidad de crecimiento de grietas por fatiga (FCGR), y se comparan los resultados de probetas extraídas de diferentes regiones de los depósitos. N2 - Additive manufacturing (AM) technology continues to make progress and allows for reaching increasingly complex and optimised designs. The chemical industry is one of the sectors where AM components have acquired relevance. There is a lack of any European directive in order to regulate the inspection, certification as well as acceptance of additively manufactured (AM) equipment subjected to pressure loads, so progression in this line becomes necessary. This work aimed to develop a design methodology for AM components based on the estimation of fatigue lifetime on those regions with a higher risk of failure. Diverse facets are involved in this study, including numerical simulations, microstructure analysis and an extensive experimental campaign. The fatigue assessment is performed based on fracture mechanics. The microstructure characteristics are dependent on the thermal history along the manufacturing process for each region and, accordingly, the mechanical properties are likewise influenced. Preliminary results of an ongoing research project for characterizing the mechanical properties in demonstrator pressure vessels produced by laser powder bed fusion (L-PBF) on stainless steel 316L are presented. The preliminary findings obtained in terms of fatigue crack growth rate (FCGR) and are detailed. Results from specimens extracted from different regions of the vessel are compared. T2 - 5th Iberian Conference on Structural Integrity IbCSI 2022 CY - Coimbra, Portugal DA - 30.03.2022 KW - Fabricación Aditiva KW - Additive Manufacturing KW - Acero 316L KW - Mecánica de Fractura KW - Predicción vida a fatiga KW - Fit4AM KW - Steel 316L KW - Fracture Mechanics KW - Fatigue lifetime prediction PY - 2022 AN - OPUS4-55241 LA - spa AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gook, S. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Hybrid laser‑arc welding of laser‑ and plasma‑cut 20‑mm‑thick structural steels N2 - It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges. KW - Hybrid laser-arc welding KW - Thick-walled steel KW - Edge quality KW - Gap bridgeability KW - Laser cutting KW - Plasma cutting PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-552013 SN - 0043-2288 VL - 66 SP - 507 EP - 514 PB - Springer AN - OPUS4-55201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schönherr, J. A. A1 - Duarte, Larissa A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Geilen, M. B. A1 - Klein, M. A1 - Oechsner, M. T1 - Robust determination of fatigue crack propagation thresholds from crack growth data N2 - The robust determination of the threshold against fatigue crack propagation DKth is of paramount importance in fracture mechanics based fatigue assessment procedures. The standards ASTM E647 and ISO 12108 introduce operational definitions of DKth based on the crack propagation rate da/dN and suggest linear fits of logarithmic DK– da/dN test data to calculate DKth. Since these fits typically suffer from a poor representation of the actual curvature of the crack propagation curve, a method for evaluating DKth using a nonlinear function is proposed. It is shown that the proposed method reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density. KW - Fatigue crack propagation threshold KW - ISO 12108 KW - ASTM E647 KW - Data evaluation methods KW - Experimental determination PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-552153 SN - 1996-1944 VL - 15 IS - 14 SP - 1 EP - 21 PB - MDPI CY - Basel AN - OPUS4-55215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fabry, Cagtay A1 - Hirthammer, Volker A1 - Scherer, Martin K. T1 - weldx - welding data exchange format N2 - Scientific welding data covers a wide range of physical domains and timescales and are measured using various different sensors. Complex and highly specialized experimental setups at different welding institutes complicate the exchange of welding research data further. The WelDX research project aims to foster the exchange of scientific data inside the welding community by developing and establishing a new open source file format suitable for the documentation of experimental welding data and upholding associated quality standards. In addition to fostering scientific collaboration inside the national and international welding community an associated advisory committee will be established to oversee the future development of the file format. The proposed file format will be developed with regard to current needs of the community regarding interoperability, data quality and performance and will be published under an appropriate open source license. By using the file format objectivity, comparability and reproducibility across different experimental setups can be improved. KW - Welding KW - Research data management KW - Open science KW - Open Data KW - WelDX PY - 2021 U6 - https://doi.org/10.5281/zenodo.6563282 PB - Zenodo CY - Geneva AN - OPUS4-55226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blasón, Sergio A1 - Werner, Tiago A1 - Kruse, Julius A1 - Gilli, Daniel A1 - Madia, Mauro T1 - Experimental procedure for the determination of intrinsic fatigue crack propagation threshold ΔKth,eff and characterization of FCGR curves on miniature steel specimens N2 - The largest percentage of component life under fatigue loading conditions is spent in the short crack regime and in the initial phase of long cracks. The use of Fracture Mechanics in the characterization of fatigue crack growth rate curves has proven to be a useful and adequate tool in the prediction of fatigue lifetimes as long as certain conditions are satisfied. All the above implies the need for a methodical and accurate procedure of assessment of the material response in order to achieve a reliable prediction of lifetime in components under safe conditions, based on the damage tolerance approach. It also highlights the need to analyse the response of increasingly reduced thicknesses, which, as time goes by, show greater differences with respect to those commonly studied and defined in standards and design guidelines, as well as to the experimental studies that can be found in the literature at present. Some examples of thin-walled components are turbine blades or certain additively manufactured parts where, additionally, variations in material properties can occur locally and should also be examined. T2 - 2nd International Symposium on Notch Mechanics (2nd ISNM) CY - Madrid, Spain DA - 03.09.2020 KW - miniature specimens; FCGR curves; intrinsic threshold PY - 2021 SP - 1 EP - 2 AN - OPUS4-55242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blason Gonzalez, Sergio A1 - Werner, Tiago A1 - Kruse, Julius A1 - Gilli, D. A1 - Madia, Mauro T1 - Procedimiento experimental para la determinación del valor ΔK umbral intrínseco y caracterización de velocidad de propagación de grietas en fatiga en probetas de acero N2 - Se presenta una guía completa del procedimiento experimental para la determinación del valor umbral ΔKth intrínseco y caracterización de curvas FCGR sobre el acero de alta resistencia S960QL empleando probetas de pequeña escala. El análisis se realiza comparando probetas SENB de diferentes geometrías, distinguiendo entre “convencionales” y “miniatura”. Las primeras con espesor (B) de 6 mm y anchura (W) de 19, y las segundas con B = 3 y dos valores distintos de W, 4 y 6 mm. A fin de identificar el valor umbral ΔKth intrínseco, la relación de cargas (R) aplicada en todos los ensayos fue 0,8. La técnica de caída de potencial (DCPD) se utilizó para la monitorización del tamaño de grieta a lo largo de los ensayos. La evaluación de los resultados experimentales confirma la equiparación de resultados entre las distintas geometrías y configuraciones de ensayo practicadas, así como la viabilidad de emplear probetas de pequeña escala en la determinación del valor umbral ΔKth intrínseco. Esto abre nuevas perspectivas en lo relativo al empleo de probetas de reducidas dimensiones en la caracterización de materiales a fatiga. A su vez, permite ofrecer una serie de recomendaciones para reproducir con éxito ensayos semejantes utilizando probetas de pequeñas dimensiones de acero y otros materiales metálicos. T2 - XXXVII Congreso del Grupo Español de Fractura CY - Online meeting DA - 07.06.2021 KW - Probetas miniatura KW - Determinación Kth intrínseco KW - Curvas FCGR KW - Acero alta resistencia KW - Recomendaciones procedimiento de ensayo PY - 2021 AN - OPUS4-55244 LA - spa AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönherr, J. A. A1 - Duarte, Larissa A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Geilen, M. B. A1 - Klein, M. A1 - Oechsner, M. T1 - Robust Determination of Fatigue Crack Propagation Thresholds from Crack Growth Data N2 - To assess the ability of cracks to grow, a robust determination of the threshold against fatigue crack propagation ∆Kth is of paramount importance. The standards ASTM E647 and ISO 12108 introduce operational definitions of ∆Kth based on the crack propagation rate da/dN. For evaluating ∆Kth, both suggest fitting a linear function to a defined subset of the logarithmic ∆K – da/dN test data, where ∆Kth follows by evaluating the linear function at da/dN = 10-7 mm/cycle and da/dN = 10-8 mm/cycle, respectively. In general, this kind of fit suffers from a bad representation of the actual curvature of the crack propagation curve. Therefore, we propose a robust method for evaluating ∆Kth using a non-linear function that reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density. The method is calibrated against a large set of S690QL crack growth data obtained from a total of 48 specimens, and validated against a set of S355NL and S960QL data (3 specimens each), obtained as a part the IBESS (integral fracture mechanics determination of the fatigue strength of welds) project. T2 - ECF23 (European Conference on Fracture 2022) CY - Madeira, Portugal DA - 27.06.2022 KW - Fatigue crack propagation threshold KW - ISO 12108 KW - ASTM E647 KW - Data evaluation methods KW - Experimental determination PY - 2022 AN - OPUS4-55252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oster, Simon A1 - Fritsch, Tobias A1 - Ulbricht, Alexander A1 - Mohr, Gunther A1 - Bruno, Giovanni A1 - Maierhofer, Christiane A1 - Altenburg, Simon T1 - On the Registration of Thermographic In Situ Monitoring Data and Computed Tomography Reference Data in the Scope of Defect Prediction in Laser Powder Bed Fusion N2 - The detection of internal irregularities is crucial for quality assessment in metal-based additive manufacturing (AM) technologies such as laser powder bed fusion (L-PBF). The utilization of in-process thermography as an in situ monitoring tool in combination with post-process X-ray micro computed tomography (XCT) as a reference technique has shown great potential for this aim. Due to the small irregularity dimensions, a precise registration of the datasets is necessary as a requirement for correlation. In this study, the registration of thermography and XCT reference datasets of a cylindric specimen containing keyhole pores is carried out for the development of a porosity prediction model. The considered datasets show variations in shape, data type and dimensionality, especially due to shrinkage and material elevation effects present in the manufactured part. Since the resulting deformations are challenging for registration, a novel preprocessing methodology is introduced that involves an adaptive volume adjustment algorithm which is based on the porosity distribution in the specimen. Thus, the implementation of a simple three-dimensional image-to-image registration is enabled. The results demonstrate the influence of the part deformation on the resulting porosity location and the importance of registration in terms of irregularity prediction. KW - Selective laser melting (SLM) KW - Laser powder bed fusion (L-PBF) KW - Additive manufacturing (AM) KW - Process monitoring KW - Infrared thermography KW - X-ray computed tomography (XCT) KW - Defect detection KW - Image registration PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-549412 VL - 12 IS - 6 SP - 1 EP - 21 PB - MDPI AN - OPUS4-54941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gumenyuk, Andrey A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gook, Sergej A1 - Rethmeier, Michael T1 - Hybrid laser-arc welding of laser and plasma-cut 20 mm thick structural steels with AC magnetic support N2 - It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges. T2 - WAITRO-Workshop “Advanced Materials and Manufacturing Technologies for Africa and Middle East Development” CY - Cairo, Egypt DA - 01.06.2022 KW - Hybrid laser arc welding KW - Laser beam welding PY - 2022 AN - OPUS4-54950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin T1 - Eine digital gestützte Qualitätssicherung für die additive Fertigung N2 - Die additive Fertigung (ugs. „3D-Druck“) ist bei der Herstellung von hochkomplexen metallischen Bauteilen, bionisch inspiriertem Leichtbau oder Prototypen nicht mehr wegzudenken. Für die konventionelle Fertigung hat sich das bestehende System der Qualitätsinfrastruktur (QI) bewährt. Die additive Fertigung vergrößert den gestalterischen Spielraum von möglichen Bauteilgeometrien und Prozessfehlern jedoch erheblich. Hier gerät die QI an ihre Grenzen, sodass die Fertigung und Zulassung sicherheitsrelevanter Bauteile sehr zeit- und kostenintensive Versuche erfordern. Eine moderne digitale QI erlaubt eine effizientere Qualitätssicherung für additiv gefertigte Bauteile. Dies erfordert eine durchgängig digitale Abbildung des physischen Materialflusses. T2 - Werner-von-Siemens Centre for Industry and Science - AM Querschnittstreffen CY - Online meeting DA - 21.06.2022 KW - Additive Fertigung KW - Qualitätssicherung KW - Digitalisierung PY - 2022 AN - OPUS4-55127 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Cagtay A1 - Hirthammer, Volker A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - WelDX - a file format for processing and archiving welding research data N2 - The talk gives an introduction into gas metal arc welding and its relation to plasma science as well as current challenges in welding research concerning research data management and the application of the FAIR principles. The WelDX project is introduced and the main goals are discussed and contrasted with the current features of the weldx API. Different internal and public facing use cases focusing on research data management and their implementation using weldx are presented. The interactive part of the presentation displays some advanced multi layer use cases and data analysis using the weldx API as well as the integration of materials properties into weldx. T2 - International Workshop on FAIR Data in Plasma Science CY - Online meeting DA - 16.05.2022 KW - WelDX KW - Open science KW - Research data management KW - Arc welding KW - Digital transformation PY - 2022 AN - OPUS4-55153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram A1 - Wossidlo, Peter A1 - Abbasi, Behboud T1 - On the question of how to analyze and apply Charpy pendulum impact test results correctly - Shortcomings in corresponding procedures and standards N2 - This paper is focused on the approximation of absorbed Charpy impact energy-temperature curves (KV-T) and the management of sub-size test piece results in Charpy pendulum impact tests. Both subjects are frequently underestimated but may have a strong impact on the assessment of product quality and structural integrity. The status of related test standards, product standards, structural integrity assessment procedures and corresponding research is reviewed. It is concluded that the state of regulation is partly insufficient and wrong. There is a wide gap between the state of knowledge in the field of materials testing and the requirements of product standards and structural integrity assessment procedures. The present paper aims at boosting and supporting the necessary discussion among the parties involved to raise the level of technical safety. Correspondingly, a large experimental database was created by Charpy impact testing of popular modern structural Steels with nominal yield strength from 235 MPa to 960 MPa. KV-T data were generated using test pieces with thicknesses between 2.5 mm and 10 mm. Different strategies for KV-T curve fitting, definition of transition temperatures, as well as upper and lower shelf energy levels were followed, and different scaling procedures were applied to the sub-size test piece results. The results show that proportional scaling of sub-size to full-size test piece results in terms of KV should be disallowed because it is a wrong approach. Regulations still incorporating such procedures should be revised as soon as possible. Existing nonproportional scaling and conversion procedures were applied. The results obtained illustrate that neither an overall nor consistent conservatism nor an adequate conservatism level can be achieved. In summary, the standardizing bodies should enforce the discussion to revise relevant test standards considering more precise specifications on Charpy data fitting. Furthermore, proposals are made for an improved management of sub-size test piece results. KW - Structural integrity assessment procedure KW - Charpy pendulum impact test KW - Sub-size test piece KW - Standard test piece KW - Curve fitting KW - Conversion of results KW - Absorbed energy KW - Transition temperature KW - Steel KW - Test standard KW - Product standard PY - 2022 U6 - https://doi.org/10.1520/JTE20210781 SN - 0090-3973 VL - 50 IS - 4 SP - 2268 EP - 2293 PB - American Society for Testing and Materials (ASTM) CY - West Conshohocken, PA AN - OPUS4-55172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quackatz, Lukas A1 - Griesche, Axel A1 - Kannengießer, Thomas T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical Concentration by Laser-Induced Breakdown Spectroscopy (LIBS) N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process. T2 - 6th International Conference on Advances in Solidification Processes CY - Le Bischenberg, France DA - 20.06.2022 KW - LIBS KW - In situ measurement KW - Duplex stainless steel KW - TIG welding PY - 2022 AN - OPUS4-55116 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis Alexander A1 - Rehmer, Birgit A1 - Graf, B. A1 - Ulbricht, Alexander A1 - Skrotzki, Birgit A1 - Rethmeier, Michael T1 - Low cycle fatigue behavior of DED-L Ti-6AL-4V N2 - Laser powder-based directed energy deposition (DED-L) is a technology that offers the possibility for 3D material deposition over hundreds of layers and has thus the potential for application in additive manufacturing (AM). However, to achieve broad industrial application as AM technology, more data and knowledge about the fabricated materials regarding the achieved properties and their relationship to the manufacturing process and the resulting microstructure is still needed. In this work, we present data regarding the low-cycle fatigue (LCF) behavior of Ti-6Al-4V. The material was fabricated using an optimized DED-L process. It features a low defect population and excellent tensile properties. To assess its LCF behavior two conventionally manufactured variants of the same alloy featuring different microstructures were additionally tested. The strain-controlled LCF tests were carried out in fully reversed mode with 0.3 % to 1.0 % axial strain amplitude from room temperature up to 400°C. The LCF behavior and failure mechanisms are described. For characterization, optical microscopy (OM), scanning electron microscopy (SEM), and micro-computed tomography (µCT) were used. The low defect population allows for a better understanding of the intrinsic material’s properties and enables a fairer comparison against the conventional variants. The fatigue lifetimes of the DED-L material are nearly independent of the test temperature. At elevated test temperatures, they are similar or higher than the lifetimes of the conventional counterparts. At room temperature, they are only surpassed by the lifetimes of one of them. The principal failure mechanism involves multiple crack initiation sites. T2 - Ninth International Conference on Low Cycle Fatigue (LCF9) CY - Berlin, Germany DA - 21.06.2022 KW - AGIL KW - Additive Manufacturing KW - Ti-6Al-4V KW - Low-Cycle-Fatigue KW - Microstructure PY - 2022 AN - OPUS4-55123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schroeder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Precipitation influence and thermodynamic prediction of HAZ properties of a GMAW S690QL with varying Ti and Nb contents N2 - For a significant increase in the strength of quenched and tempered, high-strength structural steels with a yield strength > 690 MPa, the addition of micro-alloying elements such as Nb and Ti is essential. The standard specifications for the chemical composition of these steels (e.g. in DIN EN 10025-6) often only specify limit contents for the manufacturer to achieve the specified properties. The effect of the alloying elements or their carbides and/or nitrides is sometimes completely contrary, especially in the case of dissolution and re-precipitation in the HAZ with identical filler metal. This makes it difficult to adequately predict the batch dependency regarding the weldability and the load-bearing behaviour of the welded joint. In addition, modern welding processes, such as GMAW with modified spray arc, can negatively influence the phase transformation in the heat-affected zone due to their high heat input. An undesirable property is the softening of the HAZ, as well as the opposite effect of hardening. Against this background, microalloying routes with varying Ti and Nb contents of the high-strength and quenched and tempered structural steel S690QL are systematically investigated within the framework of a DFG project. For this purpose, GMAW welding with modified spray arc is used, which is characterised by high deposition rate and allows narrower joint opening angles (α = 30°). The effect of metallurgical composition in combination with high heat exposure on the formation of a critical HAZ microstructure zone with softening and/or excessive hardening is investigated on these welds. Special attention is paid to the phase transformations and precipitation behaviour in the microstructure of the heat-affected zone and weld metal. In addition to extensive metallographic investigations of individual HAZ areas, thermodynamic phase calculations were carried out using ThermoCalc while varying the chemical composition. This provides an understanding of phase transformation and precipitation growth and dissolution during welding as a function of temperature and cooling conditions. The aim is to show the influence of the heat effect on the microstructure formation in the HAZ by means of initial investigations. Particular attention is paid here to the effect of the different microalloying concepts (Ti or Nb). T2 - The 75th IIW Annual Assembly and International Conference CY - Tokyo, Japan DA - 17.07.2022 KW - High-strength structural steel KW - GMAW KW - HAZ-softening KW - Microalloying influences KW - Thermo-Calc PY - 2022 AN - OPUS4-55342 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duarte, Larissa A1 - Madia, Mauro A1 - Zerbst, Uwe T1 - Fracture mechanics fatigue life assessmente based on effective crack propagation data obtained at closure-free conditions N2 - The use of effective crack propagation data, i.e. not affected by the crack closure mechanisms, is proposed as a reliable and robust alternative for the fatigue life assessment of cyclically loaded components. T2 - 43rd Materials Mechanics Seminar CY - Sani, Greece DA - 05.06.2022 KW - Effective crack propagation data KW - Crack-closure KW - Component assessment PY - 2022 AN - OPUS4-55044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Xiangmeng A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - The detrimental molten pool narrowing phenomenon in wire feed laser beam welding and its suppression by magnetohydrodynamic technique N2 - Element transport in the wire feed laser beam welding (WFLBW) is directly determined by the molten pool shape and thermo-fluid flow therein. In this paper, an untypical molten pool profile, i.e., elongated at its top and bottom but narrowed at the middle, is found experimentally by real-time metal/glass observa- tion and numerically by multi-physical modeling. Ex-situ X-ray fluorescence element mapping is used to characterize the element dilution status in the fusion zone. For the first time, the detrimental influence of the molten pool narrowing on the element transport is identified and discussed, combining the exper- imental and numerical results. A magnetohydrodynamic technique is utilized to suppress the narrowing, aiming at a more homogenous element distribution. It is found that due to the interaction of the two dominant circulations from the top and bottom regions of the molten pool, a low-temperature region is formed. It leads to an untypical growth of the mushy zone, narrowing the molten pool in the middle re- gion. Its detrimental effect on material mixing is non-negligible considering the direct blocking effect on the downward flow and the premature solidification at the middle region. The Lorentz force from a trans- verse oscillating magnetic field can change the flow pattern into a single-circulation type. The downward transfer channel is widened, and its premature solidification is prevented because the low-temperature- gradient region is mitigated. This paper provides a supplementary reason regarding the common issue of insufficient material mixing during LBW, and a promising technique to optimize the process. KW - Thermo-fluid flow KW - Element transport KW - Laser beam welding KW - Magnetohydrodynamics KW - Multi-physical modeling PY - 2022 U6 - https://doi.org/10.1016/j.ijheatmasstransfer.2022.122913 VL - 193 SP - 122913 PB - Elsevier B.V. AN - OPUS4-55006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quackatz, Lukas A1 - Griesche, Axel A1 - Kannengießer, Thomas T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical concentration by Laser-Induced Breakdown Spectroscopy (LIBS) N2 - Nichtrostende Duplexstähle (DSS) werden häufig verwendet, insbesondere bei Anwendungen, die eine hohe Festigkeit in Verbindung mit einer hohen Korrosionsbeständigkeit in aggressiven Medien erfordern. Beispiele hierfür sind Kraftwerkskomponenten und maritime Anwendungen. Beim Schweißen dieser Stähle kann es zu lokalen Schwankungen in der chemischen Zusammensetzung kommen. Dies führt zu einer Ferritisierung des Werkstoffs und beeinträchtigt die mechanischen Eigenschaften der Bauteile. In dieser Arbeit wurden Versuche zum Wolfram-Inertgas-Schweißen (WIG) mit DSS durchgeführt. Die Analyse der chemischen Zusammensetzung wurde in situ mit Hilfe der laserinduzierten Plasmaspektroskopie (LIBS) durchgeführt. Ziel der Arbeit ist es, die chemische Zusammensetzung in der Schweißnaht verschiedener DSS quantitativ zu messen und mögliche Einflüsse der Schweißparameter auf die Mikrostruktur des Werkstoffs zu ermitteln. Gemessen wurden die chemischen Konzentrationen der Hauptlegierungselemente Cr, Ni, Mn auf der Oberfläche der Probe während des Schweißprozesses und des Abkühlungsprozesses. Mn und Ni sind Austenitstabilisatoren, deren Gehalt beim Schweißen durch die Verwendung bestimmter hochlegierter Schweißzusatzwerkstoffe zunimmt. Die Spektren wurden alle 1,3 s in einem Abstand von etwa 2 mm aufgezeichnet. Während des Abkühlungsprozesses wurde der Ort der Messung nicht verändert. Die LIBS-Methode eignet sich nachweislich zur quantitativen Darstellung der chemischen Zusammensetzungen während des Schweißvorgangs. T2 - BMDK der Universität Magdeburg CY - Magdeburg, Germany DA - 19.05.2022 KW - LIBS KW - In situ measurement KW - Duplex stainless steel KW - TIG welding KW - Evaporation PY - 2022 AN - OPUS4-54865 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zhu, Jiangchao A1 - Madia, Mauro T1 - Burst behaviours of aero-engine turbine disk at overspeed conditions N2 - This presentation focuses on the basic ideas and current status of the development of an arithmetical method to predict the failure rotational speed of turbine disks. The certification specification requires that a gas turbine aero-engine must hold 5 minutes at overspeed conditions without critical failure. Therefore, instead of experimental proof from spin-tests using test-disks similar to engine components, it is considered to use simple specimen with similar test conditions compared to real overspeed scenarios. These test conditions, or stress fields are determined using arithmetical method, e.g. finite element method, with consideration of fracture mechanics under quasi-static conditions with a given rotational speed. Failure modes like hoop burst and rim peeling are considered during determination of stress fields. Various crack-tip parameters are used to explore the similarity of stress field between simple specimen and real overspeed scenarios. Additionally, probabilistic aspects and the implementation of a global stability criterion for overspeed analysis are also considered. T2 - 43rd Materials Mechanics Seminar CY - Sani, Chalkidiki, Greece DA - 06.06.2022 KW - Structural integrity KW - Fracture mechanics KW - Turbine disk KW - Overspeed PY - 2022 AN - OPUS4-55081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zhu, Jiangchao A1 - Madia, Mauro T1 - Fracture mechanics-based structural integrity assessment of aero-engine turbine disks under overspeed conditions N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on production-similar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. In particular, the rim-peeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk, with the crack plane perpendicular to the radial direction. The crack is therefore subjected to a biaxial stress state and grows under increasing rotational speed until it triggers the rim-peeling failure. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of J-integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest J-integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. Probabilistic aspects are also considered in the calculations. T2 - Turbo Expo 2022 CY - Rotterdam, Netherlands DA - 13.06.2022 KW - Structural integrity KW - Fracture mechanics KW - Turbine disk KW - Overspeed PY - 2022 AN - OPUS4-55082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Untersuchungsmethoden beim Fräsen additiv gefertigter schwer spanbarer Co Cr Legierungen N2 - Für den Anlagenbau werden hochbelastete Komponenten aus Co-Cr-Legierungen hergestellt. Dabei ist die Zerspanung so herausfordernd, dass additive Fertigungsschritte oft wirtschaftlicher sind. Diese bedingen aber vorwiegende heterogene, anisotrope Gefüge und Eigenschaften und bei nachfolgender Fräsbearbeitung unstetige Zerspankräfte und instabile Spanvorgänge. Hierbei können hybride Zerspanprozesse helfen, hohe Belastungen für Werkzeug und Werkstückoberfläche zu minimieren. Diesbezügliche Charakterisierungen erfordern speziell adaptierte Zerspanungsanalysen. Anhand eines Anwendungsbeispiels, bei dem eine Modifikation der Ausgangslegierung mit 1 % Hf erfolgte, wird die Wechselwirkung zwischen Gefügemorphologie und Fräsprozess dargestellt, der konventionelle mit einem hybriden ultraschallunterstützten Fräsprozess verglichen und die Charakterisierung des Werkzeugverschleißes anhand zweier verschiedener Fräser betrachtet. Analysen auftretender Prozesskräfte mittels Piezo-Mehrkomponenten-Dynamometer, der Werkzeugoszillation mittels Laser-Vibrometer und zusätzliche In-situ-Temperaturmessungen der Werkzeugschneiden mittels Highspeed-Pyrometer bilden den Kern der neuen Zerspanungsprüftechik. Die vorgestellten Untersuchungsmethoden bilden die Vorgänge bei der Zerspanung additiv gefertigter Werkstoffe detailliert und reproduzierbar ab. Sowohl Legierungsmodifikation als auch hybride Prozessbedingungen lassen gezielte Einflüsse zur deutlichen Verbesserung der Zerspanungssituation zu. T2 - Tagung Werkstoffprüfung 2021 CY - Online meeting DA - 02.12.2021 KW - Legierungsmodifikation KW - Ultraschallunterstütztes Fräsen KW - Plasma-Pulver-Auftragschweißen KW - Additive Fertigung KW - Co-Cr-Legierung PY - 2021 AN - OPUS4-54903 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Optimisation of surface residual stresses using hybrid milling processes for additive manufactured Ni alloy components N2 - Ni alloys are cost intensive materials and generally classified as difficult-to-cut materials. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. Recent studies exhibited that hybrid machining processes, such as ultrasonic-assisted milling (USAM), are suitable for achieving favourable residual stress states at the surface of difficult-to-cut Ni-Cr alloys. In this investigation, wire arc additive manufactured (WAAM) specimens of alloy 36 were finish milled under different milling conditions. In addition to the machined surfaces condition and topology, the surface-near residual stresses were analysed using X-ray diffraction (XRD). Especially for low cutting speeds, significantly improved surface properties, roughness parameters and lower mechanical and microstructural degradations were found for the specimen machined with USAM compared to conventional milling. The improved surface integrity could furthermore be observed by a significant reduction of the tensile residual stresses in the surface boundary area. T2 - ICRS11, 11th International Conference on Residual Stresses CY - Nancy, France DA - 27.03.2022 KW - Surface integrity KW - Ultrasonic-assisted milling KW - Additive manufacturing KW - Ni alloy KW - Alloy 36 PY - 2022 AN - OPUS4-54904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Untersuchungsmethoden beim Fräsen additiv gefertigter schwer spanbarer Kobalt-Chrom-Legierungen N2 - Für den Anlagenbau werden hochbelastete Komponenten aus Co-Cr-Legierungen hergestellt. Dabei ist die Zerspanung so herausfordernd, dass additive Fertigungsschritte oft wirtschaftlicher sind. Diese bedingen aber vorwiegende heterogene, anisotrope Gefüge und Eigenschaften und bei nachfolgender Fräsbearbeitung unstetige Zerspankräfte und instabile Spanvorgänge. Hierbei können hybride Zerspanprozesse helfen, hohe Belastungen für Werkzeug und Werkstückoberfläche zu minimieren. Diesbezügliche Charakterisierungen erfordern speziell adaptierte Zerspanungsanalysen. Anhand eines Anwendungsbeispiels, bei dem eine Modifikation der Ausgangslegierung mit 1 % Hf erfolgte, wird die Wechselwirkung zwischen Gefügemorphologie und Fräsprozess dargestellt, der konventionelle mit einem hybriden ultraschallunterstützten Fräsprozess verglichen und die Charakterisierung des Werkzeugverschleißes anhand zweier verschiedener Fräser betrachtet. Analysen auftretender Prozesskräfte mittels Piezo-Mehrkomponenten-Dynamometer, der Werkzeugoszillation mittels Laser-Vibrometer und zusätzliche In-situ-Temperaturmessungen der Werkzeugschneiden mittels Highspeed-Pyrometer bilden den Kern der neuen Zerspanungsprüftechnik. Die vorgestellten Untersuchungsmethoden bilden die Vorgänge bei der Zerspanung additiv gefertigter Werkstoffe detailliert und reproduzierbar ab. Sowohl Legierungsmodifikation als auch hybride Prozessbedingungen lassen gezielte Einflüsse zur deutlichen Verbesserung der Zerspanungssituation zu. T2 - Bachelor-, Master-, Doktoranden-Kolloquium CY - Online meeting DA - 26.01.2022 KW - Ultraschallunterstütztes Fräsen KW - Legierungsmodifikation KW - Additive Fertigung KW - Werkzeugverschleiß PY - 2022 AN - OPUS4-54907 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Optimisation of surface residual stresses using hybrid milling processes for additive manufactured Nickel alloy components N2 - Ni alloys are cost intensive materials and generally classified as difficult-to-cut materials. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. Recent studies exhibited that hybrid machining processes, such as ultrasonic-assisted milling (USAM), are suitable for achieving favourable residual stress states at the surface of difficult-to-cut Ni-Cr alloys. In this investigation, wire arc additive manufactured (WAAM) specimens of alloy 36 were finish milled under different milling conditions. In addition to the machined surfaces condition and topology, the surface-near residual stresses were analysed using X-ray diffraction (XRD). Especially for low cutting speeds, significantly improved surface properties, roughness parameters and lower mechanical and microstructural degradations were found for the specimen machined with USAM compared to conventional milling. The improved surface integrity could furthermore be observed by a significant reduction of the tensile residual stresses in the surface boundary area. T2 - Bachelor-, Master-, Doktoranden-Kolloquium, Otto-von-Guericke-Universität Magdeburg CY - Magdeburg, Germany DA - 18.05.2022 KW - Surface integrity KW - Ultrasonic-assisted milling KW - Additive manufacturing KW - Ni alloy KW - Alloy 36 PY - 2022 AN - OPUS4-54908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vecchiato, Luca A1 - Meneghetti, Giovanni A1 - Moda, Giovanni A1 - Madia, Mauro T1 - Fatigue limit estimation of welded joints under constant amplitude uniaxial loading adopting the cyclic R-curve analysis N2 - Most of the in-service failures of welded structures are due to fatigue damage occurring in the joints. Damage tolerant approaches based on the principles of Fracture Mechanics have been shown to play a key role in this framework, as the fatigue limit is defined by the non-propagating condition of multiple defects at the weld toe. The fatigue limit assessment can be performed using the cyclic R-curve analysis which consists in comparing the driving force of a crack propagating into a component, which depends on the geometry, material and external loads, with its resistance curve, i.e. the cyclic R-curve. The crack propagation occurs whenever the crack driving force is higher than the resistance to fatigue crack propagation, while the crack is arrested in the opposite case. Consequently, this suggests that the fatigue limit of a component is defined as that stress level at which the crack driving force curve is tangent to the crack resistance curve. In the present work, the cyclic R-curve analysis has been adopted for determining the fatigue limit of stress-relieved transverse non-load-carrying joints made of S355 structural steel and subjected to fatigue axial loadings. Experimental tests have been performed to evaluate the fatigue limit of the joints. The driving force, identified by the applied Stress Intensity Factor (SIF), has been evaluated by means of linear elastic finite element analysis taking advantage of the Peak Stress Method for its rapid estimation. Based on the experimental observations that the crack initiation and early crack growth phases in welded joints occur within the Heat Affected Zone (HAZ) the cyclic R-curve has been experimentally derived for both the base metal and HAZ material. T2 - European Conference on Fracture 2022 (ECF23) CY - Funchal, Portugal DA - 27.06.2022 KW - Welded Joints KW - Fatigue Limit KW - Cyclic R-curve PY - 2022 AN - OPUS4-55254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Bruno, Giovanni A1 - Mishurova, Tatiana A1 - Serrano Munoz, Itziar A1 - Roveda, Ilaria A1 - Fritsch, Tobias A1 - Ulbricht, Alexander A1 - Sprengel, Maximilian A1 - Schröder, Jakob T1 - Residual stresses and micromechanical properties of additively manufactured metals: why do we need a paradigm shift? N2 - An overview of the challenges and successes in the methodology to characherise residual stresses and micromechnical properties in additively manufactured metals T2 - CAM2 Annual Seminar 2022 - 5-year journey CY - Gothenburg, Sweden DA - 24.10.2022 KW - Additive Manufacturing KW - Residual stress KW - AGIL KW - MANUFACT KW - Micromechnical properties PY - 2022 AN - OPUS4-56466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raute, J. A1 - Marquardt, R. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Untersuchung zum Elektronenstrahlschweißen additiv gefertigter Ni-Basis-Bauteile N2 - Die vorliegende Untersuchung befasst sich mit dem Einfluss des Additive Manufacturing auf die Schweißeignung von Bauteilen aus Inconel 718. Hierfür wurden Proben mittels DED und L-PBF hergestellt und ihr Verhalten in Blindschweißversuchen anhand eines Vergleichs mit konventionellen Gussblechen untersucht. Im zweiten Schritt wurden die verschiedenen additiv hergestellten Proben mit dem Gussmaterial im I-Stoß sowie untereinander verschweißt. Als Schweißverfahren wurde für alle Proben das Elektronenstrahlschweißen angewandt. Zur Auswertung wurde anhand von Schliffen das Nahtprofil vermessen und die Proben auf Poren und Risse untersucht. Zusätzlich wurde die Dichte vermessen und eine Prüfung auf Oberflächenrisse durchgeführt. Das AM-Material zeigte dabei Unterschiede in Nahtform und Defektneigung im Vergleich zum Gusswerkstoff. Insbesondere die DED-proben neigten unter bestimmten Parameterkonstellationen verstärkt zu Porenbildung. Risse konnten nicht beobachtet werden. Trotz auftretender Nahtunregelmäßigkeiten wurde in den kombinierten AM-Schweißproben die Bewertungsgruppe C erreicht. Eine Prüfung der bestehenden Regelwerke zur Schweißnahtbewertung anhand der gewonnenen Erkenntnisse zu additiv gefertigten Proben im Elektronenstrahlschweißprozess zeigte keinen Ergänzungsbedarf. T2 - #additivefertigung: Metall in bestForm CY - Essen, Germany DA - 26.10.2022 KW - Elektronenstrahlschweißen KW - Additive Fertigung KW - Schweißnahtbewertung PY - 2022 SN - 978-3-96144-202-7 VL - 383 SP - 81 EP - 92 PB - DVS-Media GmbH AN - OPUS4-56173 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eissel, A. A1 - Engelking, Lorenz A1 - Treutler, K. A1 - Schroepfer, Dirk A1 - Wesling, V. A1 - Kannengießer, Thomas T1 - Investigations on influencing the microstructure of additively manufactured Co‑Cr alloys to improve subsequent machining conditions N2 - Co-Cr alloys are frequently used for highly stressed components, especially in turbine and plant construction, due to their high resistance to thermal and mechanical stress, as well as to corrosive and abrasive loads. Furthermore, they are classified as difficult-to-cut materials because of their high strength and toughness as well as their low thermal conductivity. However, for Co, an increased cost and supply risk can be observed in recent years. Therefore, additive manufacturing (AM) offers significant economic advantages due to higher material efficiency regarding repair, modification, and manufacturing of such components. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. In addition, subsequent machining, particularly contour milling, is essential to generate the required complex contours and surfaces. Hence, additive and machining manufacturing processes need to be coordinated in a complementary way, especially due to additional challenges arising in milling of heterogeneous hard-to-cut microstructures. Recently, it has been shown that modern, hybrid cutting processes, such as ultrasonic-assisted milling (US), can improve the cutting situation. In this investigation, the Co-Cr initial alloy is additionally modified with Ti and Zr up to 1 wt% with the aim to enhance the homogeneity of the microstructure and, thus, the machinability. Hence the investigation includes finish milling tests of the AM components and the comparison of US and conventional machining. Both the modifications and the ultrasonic assistance exhibit a significant effect on the machining situation; for example US causes a higher surface integrity of the finish milled surfaces compared to conventional milling. T2 - International Congress on Welding, Additive Manufacturing and associated non-destructive testing CY - Online meeting DA - 08.06.2022 KW - Cobalt-chromium alloy KW - Additive manufacturing KW - Ultrasonic-assisted milling KW - Surface integrity PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-560917 SP - 1 EP - 9 PB - Springer CY - Heidelberg AN - OPUS4-56091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - Influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a raytracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized level-set method. The PLIC-based method is discrete, resulting in noncontinuous free surface reconstruction. In the localized level-set method, a continuous free surface is reconstructed, and, thus, the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics. KW - Laser beam welding KW - Laser energy distribution KW - Weld pool dynamics KW - Ray teacing PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-562429 SN - 1042-346X VL - 34 IS - 4 SP - 042023-1 EP - 042023-8 PB - Laser Institute of America CY - Orlando, Fla. AN - OPUS4-56242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Nietzke, Jonathan A1 - Sobol, Oded T1 - Additive manufacturing for components in hydrogen technologies N2 - With the introduction of a hydrogen-based energy and national economy, safety-relevant components for hydrogen technologies are becoming increasingly important. Characteristic of hydrogen technologies are, for example, harsh environmental conditions such as cryogenic or high-pressure storage, corrosion issues in fuel cells and electrolyzers, turbines, and many more. Additive manufacturing of components is becoming increasingly important and irreplaceable for the production of complex technical systems. Using the case studies of burners for gas turbines and electrodes and membranes for polymer (PEMFC) and solid oxide (SOFC) fuel cells, this article shows the potential of additive manufacturing of components. At the same time, however, the challenge of considering divergent mechanical properties depending on the direction of assembly in a "hydrogen-compatible" manner is also highlighted. Finally, the challenges posed by additive manufacturing and hydrogen for materials testing are highlighted under scenarios that are as realistic as possible. T2 - MPA-Workshop Hydrogen CY - Online meeting DA - 10.11.2022 KW - Additive manufacturing KW - Hydrogen KW - Technologies KW - Overview KW - Component PY - 2022 AN - OPUS4-56233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marko, A. A1 - Bähring, S. A1 - Raute, J. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Transferability of ANN-generated parameter sets from welding tracks to 3D-geometries in Directed Energy Deposition N2 - Directed energy deposition (DED) has been in industrial use as a coating process for many years. Modern applications include the repair of existing components and additive manufacturing. The main advantages of DED are high deposition rates and low energy input. However, the process is influenced by a variety of parameters affecting the component quality. Artificial neural networks (ANNs) offer the possibility of mapping complex processes such as DED. They can serve as a tool for predicting optimal process parameters and quality characteristics. Previous research only refers to weld beads: a transferability to additively manufactured three-dimensional components has not been investigated. In the context of this work, an ANN is generated based on 86 weld beads. Quality categories (poor, medium, and good) are chosen as target variables to combine several quality features. The applicability of this categorization compared to conventional characteristics is discussed in detail. The ANN predicts the quality category of weld beads with an average accuracy of 81.5%. Two randomly generated parameter sets predicted as “good” by the network are then used to build tracks, coatings,walls, and cubes. It is shown that ANN trained with weld beads are suitable for complex parameter predictions in a limited way. KW - Welding parameter KW - Quality assurance KW - DED KW - Artificial neural network KW - Additive manufacturing PY - 2022 U6 - https://doi.org/10.1515/mt-2022-0054 SN - 0025-5300 VL - 64 IS - 11 SP - 1586 EP - 1596 PB - De Gruyter AN - OPUS4-56278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marko, A. A1 - Bähring, S. A1 - Raute, J. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Prognose von Qualitätsmerkmalen durch Anwendung von KI-Methoden beim Directed 10 Energy Deposition N2 - Dieser Beitrag enthält die Ergebnisse eines im Rahmen der DVS Forschung entwickelten Ansatzes zur Qualitätssicherung im Directed Energy Deposition. Es basiert auf der Verarbeitung verschiedener während des Prozesses gesammelter Sensordaten unter Anwendung Künstlicher Neuronale Netze (KNN). So ließen sich die Qualitätsmerkmale Härte und Dichte auf der Datenbasis von 50 additiv gefertigten Probenwürfel mit einer Abweichung < 2 % vorhersagen. Des Weiteren wurde die Übertragbarkeit des KNN auf eine Schaufelgeometrie untersucht. Auch hier ließen sich Härte und Dichte hervorragend prognostizieren (Abweichung < 1,5 %), sodass der Ansatz als validiert betrachtet werden kann. KW - Kl KW - Directed Energy Depositio KW - Qualitätssicherung PY - 2022 SN - 0036-7184 VL - 74 IS - 10 SP - 672 EP - 679 PB - DVS Media CY - Düsseldorf AN - OPUS4-56284 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - LTT-Zusatzwerkstoffe zur Optimierung von Schweißeigenspannungen N2 - Der Vortrag gibt eine Einführung zum Thema LTT-Zusatzwerkstoffe. Anhand experimenteller Befunde werden die Mechanismen erläutert und die Auswirkungen auf die Schweißeigenspannungen verdeutlicht. T2 - 1. LTT-Workshop des ISF RWTH Aachen CY - Aachen, Germany DA - 11.05.2022 KW - LTT-Zusatzwerkstoff KW - Hochfester Stahl KW - Eigenspannungen KW - Martensit KW - Phasenumwandlung PY - 2022 AN - OPUS4-56267 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simón Muzás, Juan A1 - Brunner-Schwer, C. A1 - Rethmeier, Michael A1 - Hilgenberg, Kai T1 - Mitigation of liquation cracking in laser welding of pairs of L-PBF processed and wrought plates of Inconel 718 N2 - Laser welding is an appropriate technique for joining Laser Powder Bed Fusion (L-PBF) parts together and to conventional wrought ones. The potential consists of profiting from synergies between additive and conventional manufacturing methods and overcoming the existing limitations of both. On the one hand, L-PBF is a widely spread metal-based additive manufacturing technique suitable for generating complex parts which can present intrinsic designed cavities, conformal cooling channels, and filigree structures contributing to sustainable manufacturing and efficiency-oriented designs. On the other hand, chamber sizes for producing L-PBF parts are limited, and the process is time-consuming. Thus, its employment is not for every geometry justified. Additionally, they are in most cases individual elements of a larger assembly and need to be joined together to conventionally fabricated parts. The present research suggests laser welding parameters to adequately bond pairs of wrought and L-PBF processed plates and two L-PBF plates of Inconel 718 in butt position. L-PBF samples are printed in three different build-up orientations. Additionally, the influence of as-built L-PBF roughness qualities and usual pre-weld preparations such as edge milling are examined. The effect of normed pre-weld heat treatments is also contemplated. Identified cracks are analyzed by means of EDS in order to confirm the present phases on the areas of interest. EBSD is also employed to obtain a clear depiction of the crystallographic texture and distribution of the hot cracks. The quality of the weldment was examined according to existing standards. Substantial differences in seam geometry and microstructure across different edge’s surface qualities and build directions of stress relieved L-PBF parts have not been detected. Nevertheless, even if no other irregularities are present in the seam, variability in liquation cracking susceptibility has been confirmed. This defect is prone to happen when parts made of this nickel-based superalloy are welded together when not enough precautions are taken. It has been determined that grain size and ductility of the material before welding play a crucial role and mitigating or intensifying these imperfections. Moreover, recommendations are presented to avoid this potential welding defect. T2 - IIW 2022 International Conference on Welding and Joining CY - Tokyo, Japan DA - 17.07.2022 KW - Hybrid Part KW - Liquation Cracking KW - Build-up Orientation KW - Pre-weld Preparation KW - Heat treatment KW - Inconel 718 KW - Laser Welding KW - Laser Powder Bed Fusion KW - Selective Laser Melting KW - SLM KW - L-PBF KW - PBF-LB/M KW - LW PY - 2022 UR - www.iiw2022.com SP - 372 EP - 375 PB - The International Institute of Welding (IIW) CY - Tokyo, Japan AN - OPUS4-56066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan A1 - Rhode, Michael A1 - Mente, Tobias A1 - Kannengießer, Thomas T1 - Experimental and numerical characterization of hydrogen diffusion in thick-walled submerged arc welded joint of S420G2+M offshore steel grade N2 - Offshore wind turbines are an important goal in national energy strategies worldwide. Foundation structures are manufactured from submerged arc welded (SAW) plates with thicknesses up to 200 mm. In that connection, high-strength steels like the S420G2+M are more and more applied offering the possibility for increased stability and load-bearing capacity of the foundations. These offshore steel grades can show a susceptibility for delayed hydrogen assisted cold cracking of the weld joints. For that purpose, a minimum waiting time (MWT) of up to 48 h (dependent on applied standards) is recommended before non-destructive testing is allowed and conducted. But this concept is based on older steel grades that have been used for three or more decades. Nowadays, the metallurgical improvements (clean steels, proper rolling, and heat treatment) of base materials and well as welding consumables must be anticipated. Hence, the MWT concept should be critically discussed as it is assumed to be very conservative. For that reason, the focus of this study was to investigate the diffusion behavior in S420G2+M steel and its multi-layer SAW joint. Electrochemical permeation experiments were carried at room temperature. Boundary conditions were anticipated in terms of using different sample thicknesses. From the experimental data, hydrogen diffusion coefficients and absorbed diffusible hydrogen concentrations had been calculated. It was shown that hydrogen diffusion in the base material is increased compared to the weld metal. In addition, the sample thickness had a significant on the calculated diffusion coefficients. The minimum and maximum diffusion coefficients had been used for numerical modelling of the hydrogen diffusion in the welding joint. It became clear that a MWT must be always regarded together with a critical initial diffusible hydrogen concentration for the evaluation of a possible delayed cracking as diffusion times were mostly > 48 h due to the thick plates. T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022 CY - Ghent, Belgium DA - 11.10.2022 KW - Hydrogen KW - Submerged arc welding KW - Diffusion KW - Minimum waiting time KW - Electrochemical permeation PY - 2022 SP - 1 EP - 11 CY - Ghent, Belgium AN - OPUS4-56075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin T1 - Eine digital gestützte Qualitätssicherung für die additive Fertigung N2 - Die Digitalisierung der Qualitätsinfrastruktur (QI) am Beispiel der Additiven Fertigung. Der Vortrag erörtert, wie die Elemente einer digitalen QI zur Qualitätssicherung und Zertifizierung in der Additiven Fertigung beitragen können. T2 - Treffen der Arbeitsgemeinschaft Additive Fertigung des VDMA CY - Coburg, Germany DA - 27.10.2022 KW - Qualitätsinfrastruktur KW - Additive Fertigung KW - Digitalisierung PY - 2022 AN - OPUS4-56165 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Ausscheidungsverhalten und Eigenschaften der schweißbedingten Wärmeeinflusszonen hochfester Stähle in Abhängigkeit der Mikrolegierungsroute N2 - Für eine signifikante Festigkeitssteigerung von vergüteten, hochfesten Feinkornbaustählen mit einer Nominalstreckgrenze ≥ 690 MPa, ist die Zugabe von Mikrolegierungselementen, wie Nb und Ti, unerlässlich. Die Normvorgaben zur chemischen Zusammensetzung dieser Stähle (bspw. in DIN EN 10025-6) geben zur Erzielung der vorgeschriebenen Eigenschaften dabei oft nur Grenzgehalte für die Hersteller vor. Die Wirkung der Legierungselemente in der WEZ ist teilweise komplett konträr. Somit wird eine adäquate Vorhersage der Chargenabhängigkeit hinsichtlich der Schweißeignung und des Tragverhaltens der Schweißverbindung erschwert. Neben metallographischen Untersuchungen einzelner WEZ-Bereiche wurden unter Variation der chemischen Zusammensetzung, thermodynamische Phasenberechnungen mittels ThermoCalc durchgeführt. Hierdurch wird ein Verständnis zur Phasentransformation, Ausscheidungswachstum und -auflösung während des Schweißens in Abhängigkeit von Temperatur und Abkühlbedingungen geschaffen. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - WEZ-Erweichung KW - Mikrolegierungseinflüsse KW - Thermodynamische Modellierung PY - 2022 SP - 1 EP - 6 AN - OPUS4-56168 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Ausscheidungsverhalten und Eigenschaften der schweißbedingten Wärmeeinflusszonen hochfester Stähle in Abhängigkeit der Mikrolegierungsroute N2 - Für eine signifikante Festigkeitssteigerung von vergüteten, hochfesten Feinkornbaustählen mit einer Nominalstreckgrenze ≥ 690 MPa, ist die Zugabe von Mikrolegierungselementen, wie Nb und Ti, unerlässlich. Die Normvorgaben zur chemischen Zusammensetzung dieser Stähle (bspw. in DIN EN 10025-6) geben zur Erzielung der vorgeschriebenen Eigenschaften dabei oft nur Grenzgehalte für die Hersteller vor. Die Wirkung der Legierungselemente in der WEZ ist teilweise komplett konträr. Somit wird eine adäquate Vorhersage der Chargenabhängigkeit hinsichtlich der Schweißeignung und des Tragverhaltens der Schweißverbindung erschwert. Neben metallographischen Untersuchungen einzelner WEZ-Bereiche wurden unter Variation der chemischen Zusammensetzung, thermodynamische Phasenberechnungen mittels ThermoCalc durchgeführt. Hierdurch wird ein Verständnis zur Phasentransformation, Ausscheidungswachstum und -auflösung während des Schweißens in Abhängigkeit von Temperatur und Abkühlbedingungen geschaffen. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - WEZ-Erweichung KW - Hochfester Feinkornbaustahl KW - ThermoCalc PY - 2022 AN - OPUS4-56169 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, T. A1 - Jäger, M. A1 - Rauch, H. A1 - Brach, K. A1 - Singh, R. A1 - Kondas, J. A1 - Uhlmann, E. A1 - Häcker, Ralf T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray. T2 - ITSC 2022 CY - Vienna, Austria DA - 04.05.2022 KW - Cold Spray KW - Copper powder particles KW - Electrical conductivity KW - Large electrical high-voltage machine PY - 2022 AN - OPUS4-56127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Sobol, Oded A1 - Schütz, S. A1 - Böllinghaus, Thomas T1 - Application of an in-situ H2Test Method N2 - The degradation effect of hydrogen on the mechanical properties of steels is well known, but still not sufficiently understood. The fast and safe market ramp up of hydrogen technologies makes it evident to evaluate a wider understanding of this topic. In general it is often described as hydrogen embrittlement. Therefore it is desirable to achieve a test method which is able to provide material properties under hydrogen atmosphere in an easy way. Currently mechanical tests under hydrogen atmosphere are executed in autoclaves. For this technique complex hardware is needed, therefore tests are expensive and test capacities are only available in a small scale. The shown test method promises a trendsetting approach for reducing costs and machine time by using hollow specimen. T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022 CY - Ghent, Belgium DA - 11.10.2022 KW - Hydrogen KW - Hollow specimen KW - In-situ KW - Test procedure PY - 2022 AN - OPUS4-56032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Breidung, Marc A1 - Wossidlo, Peter A1 - Wahl, Ken A1 - Gerwien, Peter A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Küppers, M. ED - Zimmermann, Martina T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt werden, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - Kerbschlagarbeit KW - Achsschenkel KW - Fail-safe KW - Bruchmechanische Auslegung KW - Korrelation PY - 2022 SP - 1 EP - 6 PB - DGM - Deutsche Gesellschaft für Materialkunde e.V. CY - Sankt Augustin AN - OPUS4-56152 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Breidung, Marc A1 - Wossidlo, Peter A1 - Wahl, Ken A1 - Gerwien, Peter A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Küppers, M. T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt wer-den, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - Korrelation KW - Achsschenkel KW - Fail-safe KW - Bruchmechanische Auslegung KW - Kerbschlagarbeit PY - 2022 AN - OPUS4-56153 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Wossidlo, Peter ED - Zimmermann, M. T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs - Eine ernüchternde Bilanz N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022: Werkstoffe und Bauteile auf dem Prüfstand, Prüftechnik – Kennwertermittlung – Schadensvermeidung CY - Dresden, Germany DA - 27.10.2022 KW - Kerbschlagbiegeversuch, Untermaßproben, Normalproben, Skalierung von Ergebnissen PY - 2022 SP - 1 EP - 6 PB - Deutsche Gesellschaft für Materialkunde (DGM) CY - Sankt Augustin AN - OPUS4-56155 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Wossidlo, Peter T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs – eine ernüchternde Bilanz N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - Skalierung von Ergebnissen KW - Kerbschlagbiegeversuch KW - Untermaßproben KW - Normalproben PY - 2022 AN - OPUS4-56156 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raute, J. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Untersuchung zur Herstellung von Cu-Strukturen mittels Wire Electron Beam Additive Manufacturing N2 - Das Additive Manufacturing gewinnt zunehmend an Bedeutung für die Fertigung metallischer Bauteile im industriellen Umfeld. Hierbei wird zunehmend auch auf drahtförmige Ausgangswerkstoffe gesetzt, da diese Vorteile im Handling bieten, bereits in der Industrie etabliert sind und sich in der Regel durch geringere Beschaffungskosten auszeichnen. In den letzten Jahren entwickelte sich neben den bereits im großen Umfeld untersuchten Wire-DED-Verfahren auch eine Prozessvariante unter Nutzung des Elektronenstrahls zur industriellen Marktreife. Dabei zeigt die als Wire Electron Beam Additive Manufacturing bezeichnete Technologie besondere Vorteile gegenüber anderen, zumeist Laser- oder Lichtbogen-basierten DED-Prozessen. Das Verfahren bietet vor allem Potenzial für die Verarbeitung von hochleitfähigen, reflektierenden oder oxidationsgefährdeten Werkstoffen. Insbesondere für die Herstellung von Bauteilen aus Kupferlegierungen zeigt sich der Elektronenstrahl als besonders geeignet. Um das Verfahren einem breiten Anwenderkreis in der Industrie zugänglich zu machen, fehlen jedoch übergreifende Daten zu Leistungsfähigkeit, Prozessgrenzen und Anwendungsmöglichkeiten. Die vorliegende Untersuchung beschäftigt sich mit dieser Problemstellung am Beispiel zweier Cu-Werkstoffe. Dabei werden ein korrosionsbeständiger Werkstoff aus dem maritimen Bereich sowie eine Bronze mit guten Verschleißeigenschaften aus dem Anlagenbau getestet. Über mehrstufige Testschweißungen wurden die physikalisch möglichen Prozessgrenzen ermittelt und Rückschlüsse über die Eignung der Parameter zum additiven Aufbau gezogen. Hierfür wurden zunächst optimale Bereiche für den Energieeintrag anhand von Volumenenergie sowie mögliche Schweißgeschwindigkeiten untersucht. Anschließend wurde die Skalierbarkeit des Prozesses anhand von Strahlstrom und Drahtvorschub getestet. Als wesentliche Zielgrößen wurden dabei Spurgeometrie, Aufmischung und Härte herangezogen. Die Eignung der ermittelten Parameter wurde im letzten Schritt exemplarisch anhand einer additiven Testgeometrie in Form eines Zylinders nachgewiesen. T2 - DVS Congress 2022 Große Schweißtechnische Tagung DVS CAMPUS CY - Koblenz, Germany DA - 19.09.2022 KW - WEBAM KW - Electron beam KW - EBAM KW - Wire electron beam additive manufacturing PY - 2022 SN - 978-3-96144-189-1 VL - 382 SP - 446 EP - 454 PB - DVS Media AN - OPUS4-56058 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, T. A1 - Uhlmann, E. A1 - Häcker, Ralf A1 - Jäger, M. A1 - Rauch, H. A1 - Kondas, J. A1 - Brach, K. A1 - Singh, R. T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray. T2 - ITSC 2022 CY - Wien, Austria DA - 04.05.2022 KW - Cold Spray KW - Electrical conductivity KW - Copper powder particles KW - Large electrical high-voltage machine PY - 2022 SP - 1 EP - 7 AN - OPUS4-56108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zhu, Jiangchao A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Schurig, M. A1 - Schlums, H. A1 - Conrad, F. A1 - Kontermann, C. A1 - Oechsner, M. T1 - Kennwertermittlung für die Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl N2 - Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Dazu werden zwei Typen von bruchmechanischen Proben anwendungsnah ausgelegt und aus einer Turbinenscheibe ausgeschnitten: Der erste Typ ist eine biaxiale Probe, die die Beanspruchung und den Dehnungsbehinderungszustand am Diaphragm der Turbinenscheibe abbildet, die zweite eine bruchmechanische Probe, die die einachsige Beanspruchung und den Dehnungsbehinderungszustand am Bore der Turbinenscheibe wiedergibt. Im Rahmen eines Schadentoleranzansatzkonzepts ist anschließend jeweils ein halbelliptischer Riss an den genannten Stellen der Turbinenscheibe zu betrachten. Mittels numerischer Berechnungen wird ein kritischer Punkt auf der Rissfront des Risses am Diaphragm bestimmt, dort wo die höchste Rissspitzenbelastung (J-Integral) auftritt. Auf der Basis der Rissspitzenbelastung, des Dehnungsbehinderungszustands und des entsprechenden Spannungsverhältnisses an diesem kritischen Punkt wird eine Kreuzprobe mit einem Durchriss konzipiert, die diese Verhältnisse im Bauteil widerspiegelt. Die Versuche werden unter der Temperatur am Diaphragm der Turbinenscheibe durchgeführt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt. Auch die einachsigen Versuche werden unter der Temperatur am Bore der Turbinenscheibe durchgeführt. Die Zugprobe enthält halbelliptische Oberflächenrisse. Ähnlich wie bei der Auslegung der Kreuzproben werden die Rissspitzenbelastung, der Dehnungsbehinderungszustand und das Spannungsverhältnis vergleichbar mit der Turbinenscheibe eingestellt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt. Mit den Versuchsergebnissen werden die kritischen Lasten für verschiedene Versagensmechanismen (instabiles Risswachstum, plastischer Kollaps) der bruchmechanischen Proben ermittelt, die der kritischen Überdrehzahl der Turbinenscheibe entsprechen. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - Turbine disk KW - Fracture mechanics KW - Biaxial test KW - Burst PY - 2022 AN - OPUS4-56148 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai T1 - New approach for multi material design: combination of laser beam and electromagnetic melt pool displacement by induced lorentz forces N2 - Multi-material structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatial uncoupled from the influence of the keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction (EBSD) and EDX-Analysis. The detected intermetallic phases consist of a 5 µm - 6 µm compact phase seam of Al5.6Fe2 and a needle shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN. T2 - ICALEO Orlando 2022 CY - Orlando, Florida, USA DA - 17.10.2022 KW - Electromagnetic forces KW - Joining dissimilar materials KW - Laser beam welding KW - Steel and aluminium PY - 2022 AN - OPUS4-56149 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Mente, Tobias A1 - Kannengießer, Thomas A1 - Kardjilov, Nikolay T1 - The debye waller factor for temperature distribution determination in NBEI experiments: a case study for GTAW N2 - We could show in GTAW experiments with steel samples that the attenuation of neutron transmission underneath the welding torch due to the Debye-Waller-effect correlates well with sample temperatures obtained by FE numerical simulations. This would allow principally to determine sample temperatures by measuring the neutron beam attenuation. T2 - ITMNR-9 CY - Buenos Aires, Argentina DA - 17.10.2022 KW - Debye waller factor KW - GTAW KW - Temperature distribution determination PY - 2022 AN - OPUS4-56150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El-Batahgy, A. A1 - Elkousy, M. A1 - Al-Rahman, A. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael A1 - Gook, S. T1 - Retaining Mechanical Properties of GMA-Welded Joints of 9%Ni Steel Using Experimentally Produced Matching Ferritic Filler Metal N2 - Motivated by the loss of tensile strength in 9%Ni steel arc-welded joints performed using commercially available Ni-based austenitic filler metals, the viability of retaining tensile strength using an experimentally produced matching ferritic filler metal was confirmed. Compared to the austenitic Ni-based filler metal (685 MPa), higher tensile strength in gas metal arc (GMA) welded joints was achieved using a ferritic filler metal (749 MPa) due to its microstructure being similar to the base metal (645 MPa). The microstructure of hard martensite resulted in an impact energy of 71 J (-196 °C), which was two times higher than the specified minimum value of _>34 J. The tensile and impact strength of the welded joint is affected not only by its microstructure, but also by the degree of its mechanical mismatch depending on the type of filler metal. Welds with a harder microstructure and less mechanical mismatch are important for achieving an adequate combination of tensile strength and notched impact strength. This is achievable with the cost-effective ferritic filler metal. A more desirable combination of mechanical properties is guaranteed by applying low preheating temperature (200 °C), which is a more practicable and economical solution compared to the high post-weld heat treatment (PWHT) temperature (580 °C) suggested by other research. KW - 9%Ni steel KW - Ni-based austenitic filler metal KW - Mechanical mismatching KW - Microstructure KW - Post-weld heat treatment KW - Preheating KW - Matching ferritic filler metal PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-564610 SN - 1996-1944 VL - 15 IS - 23 SP - 1 EP - 14 PB - MDPI AN - OPUS4-56461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Nietzke, Jonathan A1 - Richter, Tim A1 - Mente, Tobias A1 - Mayr, P A1 - Nitsche, A T1 - Hydrogen effect on mechanical properties and cracking of creep‑resistant 9% Cr P92 steel and P91 weld metal N2 - Martensitic 9% Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen-assisted cracking. The focus of this study was the microstructure and heat treatment efect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition. Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out; the mechanical properties were assessed and supported by detailed fractographic analysis. Finally, a hydrogen and microstructure-dependent fracture criterion is established. All investigated microstructures showed a hydrogen-infuenced degradation of the mechanical properties compared to the hydrogen-free reference samples. The as-welded martensitic P91 weld metal had the highest degree of degradation in the presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a signifcantly increased risk for hydrogen-assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted. T2 - IIW Annual Assembly, Meeting of Commission IX-C CY - Tokyo, Japan DA - 16.07.2022 KW - Creep-resisting materials KW - Welding KW - Hydrogen assisted cracking KW - Hydrogen embrittlement KW - Mechanical properties PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-564070 SN - 0043-2288 SP - 1 EP - 12 PB - Springer Nature CY - Basel (CH) AN - OPUS4-56407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai T1 - New approach for multi-material design: Combination of laser beam and electromagnetic melt pool displacement by induced Lorentz forces N2 - Multimaterial structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam, and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatially uncoupled from the influence of keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction and EDX analysis. The detected intermetallic phases consist of a 5–6 μm compact phase seam of Al5.6Fe2 and a needle-shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN. KW - Electromagnetic forces KW - Joining dissimilar materials KW - Laser beam welding KW - Steel and aluminium KW - Lorentz forces PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-564840 SN - 1042-346X VL - 35 IS - 1 SP - 1 EP - 8 PB - Laser Institute of America CY - Orlando, Fla. AN - OPUS4-56484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Herausforderungen in der additiven Fertigung sicherheitsrelevanter Komponenten N2 - Der Vortrag stellt nach einer kurzen allgemeinen Einleitung zur additiven Fertigung und des Laser Powder Bed Fusion Verfahrens einige Herausforderungen vor, die derzeitig den Einsatz von AM-Komponenten in sicherheitsrelevanten Anwendungen erschweren. Abschließend werden zwei Beispiele von Arbeiten der BAM gezeigt, die zur Überwindung dieser Herausforderungen beitragen können. T2 - Anwendertreffen des Laserverbundes Berlin-Brandenburg CY - Berlin, Germany DA - 25.11.2022 KW - Additive Fertigung KW - Laser Powder Bed Fusion PY - 2022 AN - OPUS4-56435 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Ayerdi, Jon J. A1 - Slachciak, Nadine A1 - Gradt, Thomas A1 - Krüger, Jörg A1 - Zabala, A. A1 - Spaltmann, Dirk T1 - Ultrakurzpulslaser induzierte Oxidschichten zur Reduktion von Reibung und Verschleiß auf Metalloberflächen N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nano- und Mikrostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet. T2 - Workshop "Nachhaltigkeit durch Tribologische Schichten" - Europäische Forschungsgesellschaft Dünne Schichten e.V. CY - Karlsruhe, Germany DA - 17.05.2022 KW - Laser-induzierte periodische Oberflächenstrukturen KW - Reibungsreduktion KW - Verschleißreduktion KW - Oberflächenmodifikation KW - Oxidation KW - Additive PY - 2022 AN - OPUS4-54849 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübler, Daniela A1 - Gradt, Thomas T1 - Effect of different binders and secondary carbides on NbC cermets T1 - Einfluss unterschiedlicher Binder und Sekundärkarbide auf NbC-Hartmetalle N2 - Due to the rapidly increasing price of tungsten carbide and the significant health risks associated with the wear products of WC-Co (Co3O4 and Wo3), an alternative is required. Niobium carbide (NbC) is well suited as a cutting tool due to its high melting point and low solubility in iron. So far, NbC-Ni cermets best met the requirements of high hardness and toughness. Various secondary carbides such as VC, Mo2C, TiC, but also WC were added to further improve the hardness. N2 - Aufgrund des rasanten Preisanstiegs von Wolframcarbid und signifikanter Gesundheitsrisiken, die mit den Verschleißprodukten von WC-Co-Hartmetallen (Co3O4 and Wo3) einhergehen, wird eine Alternative benötigt. Niobcarbid (NbC) ist als Zerspanwerkzeug aufgrund seiner hohen Schmelztemperatur und seiner geringen Löslichkeit in Eisen gut geeignet. Im Vergleich zu reinem NbC, führte eine vollständige Substitution von WC zu NbC-Co zu einem Anstieg der Zähigkeit und Festigkeit. Als alternative Binder wurden anschließend Nickel- und Eisengebundene Binder untersucht. Obwohl eisengebundene Hartmetalle im Vergleich zu NbC-Ni Hartmetallen eine ökonomische und kostengünstigere Alternative darstellen würden, zeigten sie einen höheren Reibkoeffizienten und eine höhere Verschleißrate. Bisher erfüllen die NbC-Ni-Hartmetalle die Anforderungen hinsichtlich einer hohen Härte und Zähigkeit am besten. Verschiedene Sekundärkarbide, wie VC, Mo2C, TiC, aber auch WC wurden zusätzlich hinzugefügt, um die Härte weiter zu steigern. Elementanalysen der NbC-Ni-MeC Hartmetalle (Me = Metall) zeigten, dass der Binder eine kubisch-flächenzentrierter Mischkristall ist, während die NbC Phase ein Mischkristall des Typs (Nb, Me)C ist. KW - Niobium carbide (NbC) KW - Cutting tool KW - Binders PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-547202 SN - 0015-7899 VL - 86 IS - 2 SP - 197 EP - 211 PB - Springer CY - Berlin AN - OPUS4-54720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco A1 - Grundtner, R. A1 - Newrkla, K. A1 - Spaltmann, Dirk A1 - Pagano, F. A1 - Nyberg, E. A1 - Heino, V. T1 - On the challenges in achieving comparable and reproducible tribological model tests N2 - An infrastructure of more than 100 tribometers (for The European Tribology Centre i-TRIBOMAT) requires procedures which ensure that the respective results are characteristic as well as descriptive, trustworthy, comparable, and reproducible. T2 - Tribology International Conference 2022 (SETCOR) CY - Barcelona, Spain DA - 28.04.2022 KW - Tribology KW - i-TRIBOMAT KW - Characterisation KW - Digitalisation KW - Harmonisation KW - Round robin tests KW - Interlaboratory tests PY - 2022 AN - OPUS4-54754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quackatz, Lukas A1 - Griesche, Axel A1 - Kannengießer, Thomas T1 - Spatially resolved EDS, XRF and LIBS measurements of the chemical composition of duplex stainless steel welds: A comparison of methods N2 - Duplex stainless steels (DSS) are used in all industries where corrosion problems play a major role. Examples include the chemical industry, the food industry and shipping industries. DSS have a balanced phase ratio of ferrite (α) and austenite (γ). Unlike single-phase stainless steels, DSS combine the advantages of these and can therefore fit many industry requirements, such as weight saving or high mechanical strength. When these steels are welded, alloying elements can burn off and condense as thin layers on cold surface regions. This loss of chemical elements can lead to changes in the microstructure. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), chemical element distributions were visualized. The results were compared with those of conventional measurement methods, such as energy dispersive X-ray analysis (EDS) and X-ray fluorescence analysis (XRF), and the results from LIBS could be validated. LIBS is suitable as a fast, straightforward measurement method for producing line scans along the weld seam and provides spatially resolved information on accumulation phenomena of burned off alloying elements. LIBS is very well suited for the detection of sub-surface elements due to the exclusively superficial ablation of the material. In addition, the measurement method has been calibrated so that quantitative statements about element concentrations can also be made. T2 - EMSLIBS 2021 CY - Online Meeting DA - 25.11.2021 KW - LIBS KW - TIG welding KW - Duplex stainless steel KW - XRF KW - EDS PY - 2022 U6 - https://doi.org/10.1016/j.sab.2022.106439 SN - 0584-8547 VL - 193 SP - 1 EP - 8 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-54837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reichelt, Manuel A1 - Cappella, Brunero T1 - Atomic force microscope study of friction at the submicron-scale during tribotests with self-mated steel N2 - Friction at the microscale during reciprocal sliding tribotests was studied for the first time with self-mated steel (100Cr6/AISI 52100) taking advantage of an atomic force microscope (AFM). To this aim, microsized steel particles were glued to the AFM-cantilever and employed as colloidal tips to perform tribotests on a steel disc. The torsion of the cantilever, which correlates with the friction force, was measured during the tests. Few tests with the same load did not yield any wear and show that the load and adhesion contributions to friction stay constant when the shape of the test particle does not change. Most of the presented tribotests engendered wear. For those tests, the increase of friction during the tribotests was attributed to the emerging plowing contribution. Furthermore, analysis of both torsion and local slope gives information on the creation of wear particles and their influence on friction. KW - Friction KW - Microtribology KW - Sliding KW - Wear PY - 2022 U6 - https://doi.org/10.1115/1.4054251 VL - 144 IS - 10 SP - 1 EP - 9 PB - ASME AN - OPUS4-54839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Nietzke, Jonathan A1 - Richter, Tim T1 - Hydrogen diffusion and desorption characteristics of a CoCrFeMnNi high entropy and a CoCrNi medium entropy alloy N2 - High-entropy alloys (HEAs) are innovative high-performance materials that have attracted more and more research attention. HEAs are characterized by a solid solution of typically five equiatomic metallic elements. In addition, medium-entropy alloys (MEA, with three elements) are of interest and become more and more important. Depending on the alloy concept, HEAs and MEAs show exceptional mechanical properties, especially high-strength and ductility combinations at both cryogenic and elevated temperatures combined with excellent corrosion resistance. Future structural HEA/MEA components can be exposed to potential applications with hydrogen containing environments like high-temperature water in pressurized nuclear reactors or aerospace structures. Other potential applications could be in materials for vessel walls in the field of cryogenic and high-pressure hydrogen storage. So far, the susceptibility of HEAs/MEAs to hydrogen assisted cracking (if any) and the hydrogen diffusion is not investigated in detail yet and can limit or extend possible applications of HEA/MEA as structural materials. In our work, we focused on the hydrogen absorption, diffusion, and distribution in a HEA (CoCrFeMnNi the original Cantor-alloy) and a MEA (CoCrNi). Cathodic hydrogen charging was carried out for the hydrogen ingress, and thermal desorption analysis (TDA) revealed complex hydrogen trapping in both alloy types up to 300 °C. The absorbed total hydrogen concentrations were > 100 ppm for the HEA and > 40 ppm for MEA. In addition, the assessment of the peak deconvolution is not trivial and must consider both experimental and microstructure influences. T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022 CY - Ghent, Belgium DA - 11.10.2022 KW - Hydrogen KW - High-entropy alloy KW - Multiple principal element alloy KW - Thermal desorption analysis KW - Diffusion PY - 2022 SP - 1 EP - 11 CY - Ghent, Belgium AN - OPUS4-56076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - AlSi10Mg KW - Laser powder bed fusion KW - Round robin KW - Reproducibility PY - 2022 AN - OPUS4-56303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF-LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - Round robin KW - Reproducibility KW - Laser powder bed fusion KW - AlSi10Mg PY - 2022 SN - 978-1-899072-54-5 SP - 1 EP - 10 PB - European Powder Metallurgy Association (EPMA) AN - OPUS4-56304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - The influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a ray-tracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized Level-Set method. The PLIC-based method is discrete, resulting in non-continuous free surface reconstruction. In the localized Level-Set method, a continuous free surface is reconstructed, and thus the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics. T2 - The 41st annual International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 17.10.2022 KW - Laser beam welding KW - Laser energy distribution KW - Weld pool dynamics KW - Ray-tracing PY - 2022 AN - OPUS4-56312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yang, Chunliang T1 - Numerical analysis of ultrasonic vibration enhanced friction stir welding of dissimilar Al/Mg alloys N2 - The ultrasonic vibration enhanced friction stir welding (UVeFSW) process has unique advantages in joining dissimilar Al/Mg alloys. While there are complex coupling mechanisms of multi-fields in the process, it is of great significance to model this process, to reveal the influence mechanism of ultrasonic vibration on the formation of Al/Mg joints. In this study, the acoustic-plastic constitutive equation was established by considering the influence of both ultrasonic softening and residual hardening on the flow stress at different temperatures and strain rates. And the ultrasonic induced friction reduction (UiFR) effect on friction coefficient in different relative directions at the FSW tool-workpiece interface was quantitatively calculated and analyzed. The Al/Mg UVeFSW process model was developed through introducing the above acoustic effects into the model of Al/Mg friction stir welding (FSW). The ultrasonic energy is stronger on the aluminum alloy side. In the stirred zone, there is the pattern distribution of ultrasonic sound pressure and energy. The heat generation at the tool-workpiece contact interface and viscous dissipation were reduced after applying ultrasonic vi-bration. Due to the UiFR effect, the projection of friction coefficient and heat flux distributions at the tool-workpiece interface present a "deformed" butterfly shape. The calculated results show that ultrasonic vibration enhanced the material flow and promoted the mixing of dissimilar materials. T2 - The 13th International Seminar "Numerical Analysis of Weldability" CY - Graz, Austria DA - 04.09.2022 KW - Numerical simulation KW - Friction stir welding KW - Ultrasonic vibration KW - Al/Mg alloys PY - 2022 AN - OPUS4-56319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Martin A1 - Gleim, Tobias A1 - Gradt, Thomas T1 - Friction coefficients for wood-wood and wood-steel contacts N2 - The friction at the interfaces between pieces of wood and steel is of crucial importance for the impact and energy absorption in impact limiters of transport casks for radioactive material. Here, the friction coefficient for the combinations wood-wood and wood-steel was measured in the temperature range between -40°C and 90°C. Results show decreasing friction with increasing temperature, ranging from 0.43 at -40°C to 0.22 for 90°C for wood-steel combinations and from 0.3 at -40°C to 0.24 at 90°C for a wood-wood combination. T2 - Sandia-BAM Workshop CY - Berlin, Germany DA - 21.11.2022 KW - Wood KW - Friction KW - Transport cask PY - 2022 AN - OPUS4-56342 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey T1 - Welding of thick metal plates with laser - Where are the limits? N2 - -With modern high-power lasers (and vacuum) penetration around 100 mm is possible -Important for industrial applications: single-pass full penetration welds with tolerances -Contactless EM-backing helps to overcome many main restrictions: -Single-pass HLAW of up to 30 mm can be realized with 20 kW laser power -Increase of the gap bridgeability and misalignement of edges -Lower sensitivity to manufacturing tolerances and edge quality; samples can be prepared by a plasma-cut instead of time-consuming milling process -Gives the possibility to increase the welding parameter window and cooling rate so that the required mechanical properties can be reached -Improved filler wire mixing behaviour T2 - AKL22 - International Laser Technology Congress CY - Aachen, Germany DA - 04.05.2022 KW - Laser hybrid welding KW - Thick-walled steel KW - High-power laser KW - Electromagnetic backing PY - 2022 AN - OPUS4-56367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Pittner, Andreas A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Einlagiges MSG-Hochleistungsschweißen von dickwandigen Baustählen mit kontaktloser elektromagnetischer Schmelzbadsicherung N2 - Diese Arbeit zeigt erstmals die Anwendung einer elektromagnetischen Schmelzbadstütze beim einlagigen MSG-Schweißen von dickwandigen Stählen. Die innovativen Entwicklungen im Bereich des Lichtbogenschweißverfahrens ermöglichen eine Erhöhung der Abschmelzleistung, um die Einschweißtiefe zu steigern. Somit kann die Lagenanzahl reduziert und die Produktivität gesteigert werden. Allerdings besteht insbesondere beim einlagigen Schweißen von dickwandigen Bauteilen in PA-Position ein erhöhtes Risiko für das gravitationsbedingte Austropfen der Schmelze an der Wurzel. Zur Verhinderung werden Badstützen eingesetzt, die mechanisch angebracht und nach dem Schweißen entfernt werden müssen, was zeit- und kostenintensiv ist. Die im Rahmen dieser Studie eingesetzte elektromagnetische Schmelzbadstütze wirkt dem gravitationsbedingten Austropfen der Schmelze entgegen und kompensiert den hydrostatischen Druck. Sie wirkt kontaktlos, was im Gegensatz zu herkömmlichen Badstützen vorteilhaft ist, so dass auf eine zeit- und kostenintensive Nachbearbeitung der Schweißnahtwurzel verzichtet werden kann. Das auf extern angelegten oszillierenden Magnetfeldern beruhende Verfahren wird dabei unterhalb des zu schweißenden Bauteils positioniert. Die Magnetfeldlinien sind quer zur Schweißrichtung ausgerichtet, sodass längs zur Schweißrichtung Wirbelströme im Werkstück und eine stets nach oben gerichtete Lorentzkraft generiert werden. Mit Hilfe der elektromagnetischen Badstütze konnten beim einlagigen MSG-Schweißen von 8 mm bis 12 mm die Tropfenbildung vermieden werden. Die innovative Technologie ermöglicht es dickwandige Bauteile einlagig zu schweißen und reduziert die Nachbearbeitungszeit deutlich. T2 - DVS Congress 2022 - Große Schweißtechnische Tagung CY - Koblenz, Germany DA - 19.09.2022 KW - Hochleistungsschweißen KW - MSG-Schweißen KW - Elektromagnetische Schmelzbadsicherung PY - 2022 AN - OPUS4-56368 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Improvement of Charpy impact toughness by using an AC magnet backing system at laser hybrid welding of thick S690QL steels N2 - The study deals with the influence of the heat input and the resulting cooling times on the microstructure and Charpy impact toughness of single-pass laser hybrid welded 20-mm thick high-strength steel S690QL. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured in-situ using a pyrometer and an optical fibre in three different depths of the seam where Charpy impact test specimens were also later taken. Thereby, three different heat inputs from 1.3 kJ/mm to 2 kJ/mm were investigated. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required impact toughness of 38 J/cm2 could be reached in dependance on applied heat input, especially at the heat input of 1.6 kJ/mm. T2 - LANE 2022: 12th CIRP Conference on Photonic Technologies CY - Fürth, Germany DA - 04.09.2022 KW - Laser hybrid welding KW - Electromagnetic backing KW - Charpy impact toughness KW - Thick-plate welding KW - Thermal cycles PY - 2022 AN - OPUS4-56369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Pittner, Andreas A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Einlagiges MSG-Hochleistungsschweißen von dickwandigen Baustählen mit kontaktloser elektromagnetischer Schmelzbadsicherung N2 - Diese Arbeit zeigt erstmals die Anwendung einer elektromagnetischen Schmelzbadsicherung beim einlagigen MSG-Schweißen von dickwandigen Stählen. Die innovativen Entwicklungen im Bereich des Lichtbogenschweißverfahrens ermöglichen eine Erhöhung der Abschmelzleistung, um die Einschweißtiefe zu steigern. Somit kann die Lagenanzahl reduziert und die Produktivität gesteigert werden. Allerdings besteht insbesondere beim einlagigen Schweißen von dickwandigen Bauteilen in PA-Position ein erhöhtes Risiko für das gravitationsbedingte Austropfen der Schmelze an der Wurzel. Zur Verhinderung werden Badsicherungen eingesetzt, die mechanisch angebracht und nach dem Schweißen entfernt werden müssen, was zeit- und kostenintensiv ist. Die im Rahmen dieser Studie eingesetzte elektromagnetische Schmelzbadsicherung wirkt dem gravitationsbedingten Austropfen der Schmelze entgegen und kompensiert den hydrostatischen Druck. Sie wirkt kontaktlos, was im Gegensatz zu herkömmlichen Badsicherungen vorteilhaft ist, so dass auf eine zeit- und kostenintensive Nachbearbeitung der Schweißnahtwurzel verzichtet werden kann. Das auf extern angelegten oszillierenden Magnetfeldern beruhende Verfahren wird dabei unterhalb des zu schweißenden Bauteils positioniert. Die Magnetfeldlinien sind quer zur Schweißrichtung ausgerichtet, sodass längs zur Schweißrichtung Wirbelströme im Werkstück und eine stets nach oben gerichtete Lorentzkraft generiert werden. Mit Hilfe der elektromagnetischen Badsicherung konnten beim einlagigen MSG-Schweißen von bis zu 10 mm dicken Blechen die Tropfenbildung vermieden werden. Die innovative Technologie ermöglicht es, dickwandige Bauteile einlagig zu schweißen und reduziert die Nachbearbeitungszeiten und -kosten deutlich. T2 - DVS Congress 2022 - Große Schweißtechnische Tagung CY - Koblenz, Germany DA - 19.09.2022 KW - Elektromagnetische Schmelzbadsicherung KW - Hochleistungsschweißen KW - MSG-Schweißen PY - 2022 SN - 978-3-96144-189-1 VL - 382 SP - 640 EP - 645 PB - DVS Media GmbH AN - OPUS4-56371 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Brunner-Schwer, C. A1 - Knöfel, F. A1 - Gook, S. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Laserstrahlhybridschweissen von Türmen für Windkraftanlagen Ökonomische und ökologische Vorteile N2 - Das Laserstrahlhybridschweißen ist beim Schweißen von Türmen für Windkraftanlagen eine Alternative zum Unterpulverschweißen von Dickblechen in Mehrlagentechnik und bietet hier ökonomische und ökologische Vorteile. Der industrielle Einsatz des Verfahrens ist jedoch durch prozessspezifische Herausforderungen eingeschränkt. Die im Beitrag beschriebene kontaktlose elektromagnetische Badstütze dient zur Erweiterung des Verfahrenspotenzials im Dickblechbereich >15 mm. KW - Elektromagnetische Badstütze KW - Laserhybridschweißen KW - Windkraftanlagen KW - Ökonomische und ökologische Vorteile PY - 2022 VL - 7 SP - 340 EP - 347 PB - DVS Media GmbH AN - OPUS4-56372 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Improvement of Charpy impact toughness by using an AC magnet backing system for laser hybrid welding of thick S690QL steels N2 - The study deals with the influence of the heat input and the resulting cooling times on the microstructure and Charpy impact toughness of single-pass laser hybrid welded 20-mm thick high-strength steel S690QL. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured in-situ using a pyrometer and an optical fibre in three different depths of the seam where Charpy impact test specimens were also later taken. Thereby, three different heat inputs from 1.3 kJ/mm to 2 kJ/mm were investigated. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required impact toughness of 38 J/cm2 could be reached in dependance on applied heat input, especially at the heat input of 1.6 kJ/mm. T2 - 12th CIRP conference on photonic technologies [lane 2022] CY - Fürth, Germany DA - 04.09.2022 KW - Thick-plate welding KW - Laser hybrid welding KW - Electromagnetic backing KW - Charpy impact toughness KW - Thermal cycles PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-563731 VL - 111 SP - 462 EP - 465 PB - Elsevier B.V. AN - OPUS4-56373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jokisch, T. A1 - Gook, S. A1 - Marko, A. A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Laser beam welding of additive manufactured components: Applicability of existing valuation regulations N2 - With additive manufacturing in the powder bed, the component size is limited by the installation space. Joint welding of additively manufactured parts offers a possibility to remove this size limitation. However, due to the specific stress and microstructure state in the additively built material, it is unclear to what extent existing evaluation rules of joint welding are also suitable for welds on additive components. This is investigated using laser beam welding of additively manufactured pipe joints. The welds are evaluated by means of visual inspection, metallographic examinations as well as computed tomography. The types of defects found are comparable to conventional components. This is an indicator that existing evaluation regulations also map the possible defects occurring for weld seams on additive components. KW - Weld imperfections KW - Additive manufacturing KW - Weldability KW - Laser welding PY - 2022 VL - 2 SP - 109 EP - 113 PB - DVS Media GmbH AN - OPUS4-56374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Elektromagnetische Schmelzbadbeeinflussung beim Laserhybridschweißen von Dickblechen N2 - Die technischen Entwicklungen in der Lasertechnologie in den letzten Jahrzehnten haben eine neue Generation von Hochleistungslasersystemen im Leistungsbereich bis zu 100 kW auf den Markt gebracht. Dennoch ist die industrielle Anwendung des Hochleistungslaserstrahlschweißens auf bis zu 15 mm dicke Bleche beschränkt. Mögliche Ursachen der Einschränkungen des Verfahrens sind z.B. die Sensibilität des Verfahrens auf Fertigungstoleranzen wie Spalt und Kantenversatz, die erhöhte Tropfenbildung bei höheren Blechdicken und eine inhomogene Verteilung des Zusatzwerkstoffes beim Laserhybridschweißen. In dieser Studie wird ein auf extern angelegte Magnetfelder basierte elektromagnetische Schmelzbadstütze eingesetzt, um die Grenzen des Verfahrens zu erweitern und die Herausforderungen zu minimieren. Der wesentliche Vorteil der elektromagnetischen Schmelzbadstütze ist, dass sie berührungslos arbeitet. Mit Hilfe der elektromagnetischen Schmelzbadstütze konnten bei 20 mm dicken Proben aus S355J2 die Tropfenbildung an der Wurzel vermieden werden. Zudem wurde der Einfluss der Kantenqualität auf die Schweißnahtqualität untersucht, wobei verschiedene Schneidverfahren zur Kantenvorbereitung eingesetzt wurden, wie z.B. Plasma-, Brenn- oder Laserschneiden. Es konnte gezeigt werden, dass auch bei schlechteren Kantenvorbereitung im Gegensatz zu gefrästen Bauteilen die Werkstoffe einlagig mittels Laserhybridschweißen bei einer hohen Schweißnahtqualität gefügt werden konnten. Bei plasmageschnittenen Proben wurden zudem eine Spaltüberbrückbarkeit bzw. Kantenversatz von bis zu 2 mm sicher überbrückt. Des Weiteren war es mit Hilfe der externen Magnetfelder möglich, die Durchmischung des Zusatzwerkstoffes über die gesamte Schweißnahttiefe deutlich zu homogenisieren. T2 - 42. Assistentenseminar der Wissenschaftlichen Gesellschaft Fügetechnik e.V. CY - Blankenau, Germany DA - 06.10.2021 KW - Elektromagnetische Schmelzbadstütze KW - Laserhybridschweißen KW - Dickblech PY - 2022 VL - 385 SP - 1 EP - 7 PB - DVS Media GmbH AN - OPUS4-56375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin A1 - Poka, Konstantin A1 - Hilgenberg, Kai T1 - QI-Digital - Qualitätssicherung für die Additive Fertigung N2 - Für die konventionelle Fertigung hat sich das bestehende System der Qualitätsinfrastruktur (QI) bewährt. Die additive Fertigung vergrößert den gestalterischen Spielraum von möglichen Bauteilgeometrien und Prozessfehlern jedoch erheblich. Hier gerät die QI an ihre Grenzen, sodass die Fertigung und Zulassung sicherheits-relevanter Bauteile sehr zeit- und kostenintensive Versuche erfordern. Eine moderne digitale QI erlaubt eine effizientere Qualitätssicherung für additiv gefertigte Bauteile. Dies erfordert eine durchgängig digitale Abbildung des physischen Materialflusses. T2 - QI-Forum CY - Berlin, Germany DA - 11.10.2022 KW - Additive Fertigung KW - Qualitätssicherung KW - Digitalisierung PY - 2022 AN - OPUS4-56382 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin T1 - Digitalisierung der Qualitätsinfrastruktur am Beispiel der Additiven Fertigung N2 - Die Digitalisierung der Qualitätsinfrastruktur (QI) am Beispiel der Additiven Fertigung. Der Vortrag erörtert, wie man mit Elementen einer digitalen QI (DPP, DCoC, Smart Standard, DCC, etc.) aktuelle Herausforderungen in der Qualitätssicherung additiv gefertigter Bauteile adressieren kann. T2 - FORUM Qualitätssicherung in der additiven Fertigung – Quality Engineering CY - Online meeting DA - 13.09.2022 KW - Additive Fertigung KW - Qualitätssicherung KW - Digitalisierung KW - Qualitätsinfrastruktur PY - 2022 AN - OPUS4-56383 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bakir, Nasim A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Influence of the weld pool geometry on solidification cracking in partial penetration high power laser beam welding N2 - Solidification cracking is still a serious problem in laser beam welding, especially in the welding of thick-walled plates. The influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is investigated within scope of this study. Therefore, a specific experimental setup of steel and quartz glass in butt configuration and on the side with high-speed camera were used to record the weld pool shape. In addition, the influence of laser inclination angle on the weld pool geometry and on solidification crack formation was investigated. The results show a bulge in the weld pool root, which is separated from an upper region by a necking region. This leads to a case where there are three different longitudinal region lengths with different solidification zones. This temporal sequence of solidification strongly promotes the formation of solidification cracks in the weld root. T2 - 12th CIRP Conference on photonic technologies (LANE 2022) CY - Fürth, Germany DA - 04.09.2022 KW - Laser beam welding KW - Partial penetration KW - Weld pool shape PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-563940 VL - 111 SP - 397 EP - 400 PB - Elsevier B.V. AN - OPUS4-56394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bakir, Nasim A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Influence of the weld pool geometry on solidification cracking in partial penetration high power laser beam welding N2 - Solidification cracking is still a serious problem in laser beam welding, especially in the welding of thick-walled plates. The influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is investigated within scope of this study. Therefore, a specific experimental setup of steel and quartz glass in butt configuration and on the side with high-speed camera were used to record the weld pool shape. In addition, the influence of laser inclination angle on the weld pool geometry and on solidification crack formation was investigated. The results show a bulge in the weld pool root, which is separated from an upper region by a necking region. This leads to a case where there are three different longitudinal region lengths with different solidification zones. This temporal sequence of solidification strongly promotes the formation of solidification cracks in the weld root. T2 - LANE 2022: 12th CIRP Conference on Photonic Technologies CY - Fürth, Germany DA - 04.09.2022 KW - Laser beam welding KW - Weld pool shape KW - Solidification craking PY - 2022 AN - OPUS4-56395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yang, Fan A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Putra, Stephen Nugraha A1 - Rethmeier, Michael T1 - Numerical analysis of the influence of an auxiliary oscillating magnetic field on suppressing the porosity formation in deep penetration laser beam welding of aluminum alloys N2 - The contactless magnetohydrodynamic technology has been considered as a potential and promising method to improve the weld qualities of deep penetration laser beam welding. In this paper, numerical investigations are conducted to study the influence of the auxiliary oscillating magnetic field on the porosity suppression in laser beam welding of 5754 aluminum alloy. To obtain a deeper insight into the suppression mechanism, a three-dimensional transient multi-physical model is developed to calculate the heat transfer, fluid flow, keyhole dynamic, and magnetohydrodynamics. A ray tracing algorithm is employed to calculate the laser energy distribution on the keyhole wall. A time-averaged downward Lorentz force is produced by an oscillating magnetic field. This force acts in the molten pool, leading to a dominant downward flow motion in the longitudinal section, which blocks the bubble migration from the keyhole tip to the rear part of the molten pool. Therefore, the possibility for the bubbles to be captured by the solidification front is reduced. The electromagnetic expulsive force provides an additional upward escaping speed for the bubbles of 1 m/s ~ 5 m/s in the lower and middle region of the molten pool. The simulation results are in a good agreement with experimental measurements. Based on the results obtained in this study, a better understanding of the underlying physics in laser beam welding enhanced by an auxiliary oscillating magnetic field can be provided and thus the welding process can be further optimized reducing the porosity formation. T2 - The 13th International Seminar "Numerical Analysis of Weldability" CY - Graz, Austria DA - 04.09.2022 KW - Deep penetration laser beam welding KW - Oscillating magnetic field KW - Numerical simulation KW - Porosity KW - Molten pool behaviour PY - 2022 AN - OPUS4-56328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oster, Simon A1 - Becker, Tina A1 - Breese, Philipp Peter A1 - Scheuschner, Nils A1 - Maierhofer, Christiane A1 - Ulbricht, Alexander A1 - Frisch, Tobias A1 - Mohr, Gunther A1 - Altenburg, Simon T1 - Defect prediction in laser powder bed fusion based on thermographic features utilizing convolutional neural networks N2 - The appearance of irregularities such as keyhole porosity is a major challenge for the production of metal parts by laser powder bed fusion (PBF-LB/M). The utilization of thermographic in-situ monitoring is a promising approach to extract the thermal history which is closely related to the formation of irregularities. In this study, we investigate the utilization of convolutional neural networks to predict keyhole porosity based on thermographic features. Here, the porosity information calculated from an x-ray micro computed tomography scan is used as reference. Feature engineering is performed to enable the model to learn the complex physical characteristics of the porosity formation. The model is examined with regard to the choice of hyperparameters, the significance of thermal features and characteristics of the data acquisition. Based on the results, future demands on irregularity prediction in PBF-LB/M are derived. T2 - GIMC SIMAI YOUNG 2022 CY - Pavia, Italy DA - 29.09.2022 KW - Laser Powder Bed Fusion KW - Thermography KW - In-situ Monitoring KW - Convolutional Neural Networks PY - 2022 AN - OPUS4-56331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Meng, Xiangmeng A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. First, the local variation of the solidification sequence of the weld pool causes an increase in the hotcracking susceptibility due to a locally delayed solidification. Second, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g., during the welding with filler materials, is blocked. This leads to a nonhomogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results that were supported by selected experimental validation results. T2 - International Congress of Applications of Lasers & Electro-Optics 2022 CY - Orlando, FL, USA DA - 17.10.2022 KW - Weld pool shape KW - Laser beam welding KW - Solidification KW - Porosity KW - Element distribution KW - Numerical process simulation PY - 2022 AN - OPUS4-56335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael A1 - Bakir, Nasim A1 - Üstündag, Ömer T1 - Schweisstechnische Anwendungen von Hochleistungslasern für dickwandige Konstruktionen N2 - Der Beitrag befasst sich mit dem Potential der schweißtechnischen Anwendung von Hochleistungslasern für die moderne industrielle Fertigung. Die Ergebnisse eines abgeschlossenen IGF-Projektes werden präsentiert und im Hinblick auf die Vorteile des vorgeschlagenen EM-unterstützten Laser-MSG-Hybridschweißverfahrens ggü. konventionellen Schweißverfahren diskutiert. Vor allem die Eigenschaften des Verfahrens, wie eine bessere Spaltüberbrückbarkeit, eine bessere Durchmischung des Zusatzmaterials und gute mechanisch-technologische Eigenschaften der Schweißverbindungen werden hervorgehoben. T2 - Anwendertreffen des Laserverbundes Berlin-Brandenburg CY - Berlin, Germany DA - 25.11.2022 KW - Laserstrahlschweißen KW - Hybridschweißen KW - Elektromagnetische Schmelzbadkontrolle PY - 2022 AN - OPUS4-56571 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roveda, Ilaria A1 - Serrano Munoz, Itziar A1 - Mishurova, Tatiana A1 - Madia, Mauro A1 - Pirling, T. A1 - Evans, Alexander A1 - Klaus, M. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - Influence of a 265 °C heat treatment on the residual stress state of a PBF-LB/M AlSi10Mg alloy N2 - Laser Powder Bed Fusion (PBF-LB/M) additive manufacturing (AM) induces high magnitude residual stress (RS) in structures due to the extremely heterogeneous cooling and heating rates. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their generation and evolution after post-process heat treatments. In this study, one of the few of its kind, the RS relaxation induced in an as-built PBF-LB/M AlSi10Mg material by a low-temperature heat treatment (265 °C for 1 h) is studied by means of X-ray and neutron diffraction. Since the specimens are manufactured using a baseplate heated up to 200 °C, low RS are found in the as-built condition. After heat treatment a redistribution of the RS is observed, while their magnitude remains constant. It is proposed that the redistribution is induced by a repartition of stresses between the a-aluminium matrix and the silicon phase, as the morphology of the silicon phase is affected by the heat treatment. A considerable scatter is observed in the neutron diffraction RS profiles, which is principally correlated to the presence (or absence) of pockets of porosity developed at the borders of the chessboard pattern. KW - Neutron diffraction KW - Additive manufacturing PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-565115 SN - 1573-4803 VL - 57 SP - 22082 EP - 22098 PB - Springer Science + Business Media CY - Dordrecht AN - OPUS4-56511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baensch, Franziska A1 - Baer, Wolfram A1 - Wossidlo, Peter A1 - Habib, Abdel Karim T1 - Damage evolution detection in a pipeline segment under bending by means of acoustic emission N2 - A steel pipeline segment of 2.5 m length was subjected to quasi-static four-point bending load in three steps for studying the initial cracking and damage accumulation based on the Acoustic Emission (AE) technique and by the direct current potential drop (DCPD) technique. For the latter, a new post-test analysis method was established. AE is found more sensitive to crack initiation than DCPD. Formation of mesoscopic and macroscopic cracks as well as their closure and the resulting friction generate weighted peak frequencies below 400 kHz, whereas microscopic cracking produces AE with broad band spectra identifiable by weighted peak frequencies above 400 kHz. Critical states alike the maximum load level and the leak opening were accompanied by peak amplitudes above 85 dBAE. This rather fundamental study provides a data base for possibly developing advanced strategies of detection and alarm systems based on acoustic monitoring of pipelines, or at least, steel structures. KW - Crack KW - Accoustic emission KW - Frequency domain KW - Potential drop technique KW - Fracture PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-565171 SN - 0308-0161 VL - 201 IS - 104863 SP - 1 EP - 9 PB - Elsevier Science CY - Amsterdam AN - OPUS4-56517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-2 wurden die Legierungsmodifikationen des CoCr-Ausgangswerkstoffes sowie des FeNi36-Ausgangswerkstoffes abgeschlossen. In AP-4 wurden Zerspanversuche an den Modifikationen des FeNi36-Ausgangswerkstoffes sowie des CoCr-Ausgangswerkstoffes gefahren. Ferner wurden die zur Übertragung auf den MSG-Prozess ausgewählten Modifikationen beider Ausgangswerkstoffe vorgestellt. T2 - Sitzung des Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“ des DVS CY - Magdeburg, Germany DA - 09.11.2022 KW - Legierungsmodifikation KW - Ultraschallunterstütztes Fräsen KW - Additive Fertigung PY - 2022 AN - OPUS4-56609 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Regelwerke aus Forschungsvorhaben der Forschungsvereinigung des DVS: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungsle¬gierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Es werden die Ergebnisse der Mikrostruktur und der Zerspanbarkeit der Modifikationen der FeNi36-Referenzlegierung mit 0,33 Gew.-% Ti, Zr sowie Hf und der Modifikationen der CoCr-Referenzlegierung mit 1 Gew.-% Ti, Zr sowie Hf vorgestellt. Abschließend werden aus den Ergebnissen Handlungsempfehlungen abgeleitet. T2 - Sitzung der Arbeitsgruppe (AG) V 12 „Additive Fertigung“ CY - Online meeting DA - 23.11.2022 KW - Legierungsmodifikation KW - Ultraschallunterstütztes Fräsen KW - Additive Fertigung PY - 2022 AN - OPUS4-56610 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Meng, Xiangmeng A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. Firstly, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Secondly, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g. during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results which were supported by selected experimental validation results. T2 - International Congress of Applications of Lasers & Electro-Optics 2022 CY - Orlando, FL, USA DA - 17.10.2022 KW - Weld pool shape KW - Laser beam welding KW - Solidification KW - Porosity KW - Numerical process simulation PY - 2022 SP - 1 AN - OPUS4-56532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - The influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a ray-tracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized Level-Set method. The PLIC-based method is discrete, resulting in non-continuous free surface reconstruction. In the localized Level-Set method, a continuous free surface is reconstructed, and thus the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics. T2 - International Congress of Applications of Lasers & Electro-Optics 2022 CY - Orlando, FL, USA DA - 17.10.2022 KW - Laser beam welding KW - laser energy distribution KW - Weld pool dynamics KW - Ray-tracing PY - 2022 SP - 1 EP - 9 AN - OPUS4-56533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merz, Benjamin A1 - Mohr, Gunther A1 - Hilgenberg, Kai T1 - Position Detection for Hybrid Repair of gas turbine blades using PBF-LB/M N2 - This poster presents a workflow for camera-based position detection of components within PBF-LB/M machines. This enables a hybrid repair process of highly stressed components such as gas turbine blades using PBF-LB/M. T2 - Kuratoriumsführung CY - Berlin, Germany DA - 21.06.2022 KW - Additive Manufacturing KW - PBF-LB/M KW - Position detection KW - Camera KW - Image processing PY - 2022 AN - OPUS4-56587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz A1 - Schröpfer, Dirk A1 - Kannengießer, Thomas T1 - Untersuchungen zum Einfluss der Amplitude beim ultraschallunterstützten Schlichtfräsen schwer spanbarer FeNi Legierungen N2 - Es werden erzielte Ergebnisse des ultraschallunterstützen Schlichtfräsens einer schwer spanbaren FeNi-Legierung vorgestellt. Dabei wird der Einfluss der Amplitude der Ultraschallunterstützung auf die Zerspankraft sowie die Oberflächenintegrität untersucht, wobei ein besonderer Fokus auf die Passivkraft gelegt wird. Die Ultraschallunterstützung bedingt beim Schlichtfräsen der Alloy 36 im Vergleich zum konventionellen Fräsprozess eine signifikante Reduzierung der resultierenden Zerspankraft sowie der Rauheit. Außerdem werden oberflächennahen Druckeigenspannungen induziert. Eine Angehobene Osziallations-Amplitude beim ultraschallunterstützten Fräsen bewirkt eine Erhöhung des Anteils der Passivkraft an der resultierenden Zerspankraft sowie eine Erhöhung der oberflächennahen Druckeigenspannungen und eine Verringerung von Oberflächendefekten und Rauheitskennwerten. T2 - Bachelor-, Master-, Doktoranden-Kolloquium CY - Magdeburg, Germany DA - 30.11.2022 KW - Ultraschallunterstütztes Fräsen KW - Alloy 36 KW - Oberflächenintegrität PY - 2022 AN - OPUS4-56612 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eissel, A. A1 - Engelking, Lorenz A1 - Treutler, K. A1 - Schröpfer, Dirk A1 - Wesling, V. A1 - Kannengießer, Thomas T1 - Bericht zum Fortschritt des laufenden Projekts:„Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungsle¬gierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Im vorliegenden Beitrag werden für die beiden untersuchten FeNi und CoCr-Legierungen wesentliche Zusammenhänge zwischen ver¬schiedenen Legierungsmodifikationen, der entstehenden Gefüge¬morphologie und den Zerspanungseigenschaften von mittels PTA additiv gefertigter Proben dargestellt. Hierbei ließen sich Ti, Zr und Hf pulvermetallurgisch zu den jeweiligen Ausgangsschweißzusätzen hinzulegieren. T2 - #additivefertigung: Metall in bestForm CY - Essen, Germany DA - 26.10.2022 KW - Legierungsmodifikation KW - Ultraschallunterstütztes Fräsen KW - Additive Fertigung PY - 2022 AN - OPUS4-56613 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eissel, A. A1 - Engelking, Lorenz A1 - Treutler, K. A1 - Schröpfer, Dirk A1 - Wesling, V. A1 - Kannengießer, Thomas T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungslegierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Im vorliegenden Beitrag werden für die beiden untersuchten FeNi- und CoCr-Legierungen wesentliche Zusammenhänge zwischen verschiedenen Legierungsmodifikationen, der entstehenden Gefügemorphologie und den Zerspanungseigenschaften von mittels PTA additiv gefertigter Proben dargestellt. Hierbei ließen sich Ti, Zr und Hf pulvermetallurgisch zu den jeweiligen Ausgangsschweißzusätzen hinzulegieren. T2 - #additivefertigung: Metall in bestForm CY - Essen, Germany DA - 26.10.2022 KW - Legierungsmodifikation KW - Ultraschallunterstütztes Fräsen KW - Additive Fertigung PY - 2022 SN - 978-3-96144-202-7 VL - 383 SP - 93 EP - 99 PB - DVS-Media GmbH AN - OPUS4-56615 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Giese, Marcel A1 - Richter, Tim A1 - Rhode, Michael A1 - Schröpfer, Dirk T1 - Experimentelle Charakterisierung der WIG-Schweißeignung einer Hoch- und Mittelentropie-Legierung N2 - Hoch- und Mittelentropie-Legierungen (engl. High/Medium Entropy Alloys–HEA/MEA) sind relativ neue Werkstoffklassen. Im Gegensatz zu herkömmlichen Legierungen bestehen HEA aus fünf bzw. MEA aus drei oder vier Legierungselementen im äquiatomaren Gleichgewicht. Um diese als reale Bauteile in die Anwendung zu überführen, muss die Verarbeitbarkeit ausführlich erforscht werden. In dieser Präsentation werden dafür erste Ergebnisse der schweißtechnischen Verarbeitung mittels WIG-Schweißen dargestellt. Dazu wurden zunächst die Schweißparameter mit einer Referenzlegierung (Ni-Basislegierung: 2.4858) bestimmt und auf eine CoCrFeMnNi-HEA sowie eine CoCrNi-MEA übertragen. T2 - OVGU-Kolloquium CY - Online meeting DA - 23.06.2021 KW - Hochentropielegierung KW - Mediumentropielegierung KW - WIG-Schweißen PY - 2021 AN - OPUS4-56621 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eissel, A. A1 - Engelking, Lorenz A1 - Treutler, K. A1 - Schröpfer, Dirk A1 - Wesling, V. A1 - Kannengießer, Thomas T1 - Alloy modification for additive manufactured Ni alloy components Part I: Effect on microstructure and hardness N2 - Alloy 36 is an iron-based alloy with 36% nickel. It is used in applications in which dimensional stability is critical, such as molding tools for composite materials in aerospace and automotive applications. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components. Additively manufactured components have a heterogeneous microstructure and anisotropic mechanical properties. In addition, the manufactured components require subsequent machining surface finishing due to the high requirements. Nickel iron alloys are difficult to machine. Additionally, inhomogeneous microstructure may lead to unstable cutting forces and conditions. Alloy modifications are made to the alloy 36. For this purpose, titanium, zirconium and niobium are added up to 1 % by mass each. Plasma-Transferred-Arc is used for the welding tests. The hardness profile is determined on the transverse section. The initial structure as well as the modifications have an austenitic structure. The microstructure of the modifications of Alloy 36 with 1% Ti and 1% Zr is not refined, instead the grain size increases. T2 - IIW C-II Intermediate meeting CY - Online meeting DA - 17.03.2022 KW - Alloy modification KW - Alloy 36 KW - Additive manufacturing PY - 2022 AN - OPUS4-56622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharf-Wildenhain, R. A1 - Hälsig, A. A1 - Hensel, J. A1 - Wandtke, Karsten A1 - Schröpfer, Dirk A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - Einfluss von Wärmeführung und Bauteildesign auf die Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein. T2 - DVS Congress 2022 CY - Koblenz, Germany DA - 19.09.2022 KW - WAAM KW - Eigenspannungen KW - Additive Fertigung KW - Hochfester Stahl KW - Kaltrisssicherheit KW - Windenergie KW - Wärmeführung PY - 2022 AN - OPUS4-56718 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharf-Wildenhain, R. A1 - Hälsig, A. A1 - Hensel, J. A1 - Wandtke, Karsten A1 - Schröpfer, Dirk A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - Einfluss von Wärmeführung und Bauteildesign auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein. T2 - DVS Congress 2022 CY - Koblenz, Germany DA - 19.09.2022 KW - MAG-Schweißen KW - Additive Fertigung KW - Eigenspannungen KW - Hochfester Stahl KW - Kaltrisssicherheit KW - Wärmeführung KW - Windenergie PY - 2022 SN - 978-3-96144-189-1 VL - 382 SP - 737 EP - 745 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-56719 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -