59351
2024
eng
1
11
1
14
article
MDPI
Basel
1
--
--
--
Residual Stress Evolution during Slot Milling for Repair Welding and Wire Arc Additive Manufacturing of High-Strength Steel Components
High-strength steels offer potential for weight optimization due to reduced wall thicknesses in modern constructions. Additive manufacturing processes such as Wire Arc Additive Manufacturing (WAAM) enable the resource-efficient production of structures. In the case of defects occurring in weld seams orWAAM components due to unstable process conditions, the economical solution is local gouging or machining and repair welding. It is important to understand the effects of machining steps on the multiaxial stress state in conjunction with the design-related shrinkage restraints. Research into how welding and slot milling of welds andWAAM structures affects residual stresses is still lacking. For this reason, component-related investigations with high-strength steels with yield strengths ≥790 MPa are carried out in our research. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyze the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and microstructure of the specimens with the initial residual stresses induced by welding. Subsequent repair welds can result in significantly higher residual stresses.
Welding of Modern High-Strength Steels — Correlations between Process, Structure and Joint Properties
10.3390/met14010082
urn:nbn:de:kobv:b43-593515
publish
12.02.2024
Creative Commons - CC BY - Namensnennung 4.0 International
Karsten Wandtke
eng
uncontrolled
High strength steels
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Residual stress
eng
uncontrolled
Repair welding
eng
uncontrolled
Ditigtal image correlation
Ingenieurwissenschaften und zugeordnete Tätigkeiten
Angewandte Physik
9 Komponentensicherheit
9.2 Versuchsanlagen und Prüftechnik
9.4 Integrität von Schweißverbindungen
Infrastruktur
Material
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
Wissenschaftliche Artikel der BAM
Additive Fertigung
Leichtbau
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/59351/metals-14-00082-v2.pdf
58828
2023
eng
lecture
0
--
--
--
BAM activities in material characterization by advanced X-ray imaging
The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique). Also, two successful research project in collaboration with CAM2, Sweden are presented.
CAM2 Annual Meeting
Gothenburg, Sweden
25.10.2023
publish
false
true
0
Tatiana Mishurova
Giovanni Bruno
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Residual stress
eng
uncontrolled
X-ray computed tomography
Analytische Chemie
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
Material
Chemie und Prozesstechnik
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
58866
2023
eng
lecture
0
--
--
--
Prediction of the fatigue limit of additively manufactured metallic materials
Structural alloys are largely employed in key industrial sectors and their demand is predicted to rise rapidly for the next decades. Most of these materials require a large amount of energy for extraction and manufacturing, which causes the emission of greenhouse gases and other pollutants. Therefore, strategies for improving the sustainability of structural metallic alloys are urgently needed.
Additive Manufacturing (AM), in particular Laser Powder Bed Fusion (PBF-LB/M), aims to be a sustainable manufacturing process, as it allows the build-up of complex geometry in near net-shape from 3D models, while minimizing material waste and the energy required for the process and post-process treatments.
Nevertheless, the application of additively manufactured parts in structural safety-relevant applications is still hindered by the poor fatigue performance. The cause of this has been mainly attributed to the presence of manufacturing defects and surface roughness. Therefore, a huge effort has been made to optimize the process parameters and to introduce post-process treatments to minimize the defect content. However, material flaws cannot be fully eliminated, but these can be considered in a damage tolerance framework for the prediction of the fatigue performance of additively manufactured metallic materials, which is essential for part design and qualification.
This work aims at presenting different modelling strategies for the prediction of the fatigue limit of AM metals. Simple empirical models and more complex models based on fatigue short crack propagation are proposed. The investigated material is an AlSi10Mg alloy fabricated by PBF-LB/M and subjected to two different low-temperature heat-treatments (265°C for 1 h and 300°C for 2h). The results show that the models can provide good approximation of the fatigue limits and help in the interpretation of the scatter of fatigue data.
ASTM International Conference on Advanced Manufacturing
Washington DC, USA
30.10.2023
03.11.2023
publish
false
true
0
Mauro Madia
eng
uncontrolled
Additive Manufacturing
eng
uncontrolled
AlSi10Mg
eng
uncontrolled
Fatigue
eng
uncontrolled
Residual stress
eng
uncontrolled
Microstructure
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
9 Komponentensicherheit
9.4 Integrität von Schweißverbindungen
Material
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
56982
2023
eng
poster
0
--
--
--
Effect of heat treatment on residual stress in additively manufactured AlSi10Mg
Al-Si alloys produced by Laser Powder Bed Fusion (PBFLB) allow the fabrication of lightweight free-shape components. Due to the extremely heterogeneous cooling and heating, PBF-LB induces high magnitude residual stress (RS) and a fine Si microstructure. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their evolution in as-built state (AB) and after post-process heat treatments (HT). RS in single edge notch bending (SENB) subjected to different HT are investigated (HT1: 1h at 265°C and HT2: 2h at 300°C).
ESRF User Meeting 2023
Grenoble, France
07.02.2023
publish
false
true
Tatiana Mishurova
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Laser powder bed fusion
eng
uncontrolled
Residual stress
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
Material
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
57047
2023
eng
lecture
0
--
--
--
3D imaging and residual stress analysis for AM Materials
The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique).
Seminar at Integrated Additive Manufacturing center, Politecnico Torino
Turin, Italy
14.02.2023
publish
false
true
0
Tatiana Mishurova
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Laser powder bed fusion
eng
uncontrolled
Residual stress
eng
uncontrolled
Computed tomography
eng
uncontrolled
Synchrotron X-ray diffraction
Analytische Chemie
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
Material
Chemie und Prozesstechnik
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
57833
2023
eng
1076
1090
Pt 4
56
article
1
--
--
--
Texture-based residual stress analysis of laser powder bed fused Inconel 718 parts
Although layer-based additive manufacturing methods such as laser powder bed fusion (PBF-LB) offer an immense geometrical freedom in design, they are typically subject to a build-up of internal stress (i.e. thermal stress) during manufacturing. As a consequence, significant residual stress (RS) is retained in the final part as a footprint of these internal stresses. Furthermore, localized melting and solidification inherently induce columnar-type grain growth accompanied by crystallographic texture. Although diffraction-based methods are commonly used to determine the RS distribution in PBF-LB parts, such features pose metrological challenges in their application. In theory, preferred grain orientation invalidates the hypothesis of isotropic material behavior underlying the common methods to determine RS. In this work, more refined methods are employed to determine RS in PBF-LB/M/IN718 prisms, based on crystallographic texture data. In fact, the employment of direction-dependent elastic constants (i.e. stress factors) for the calculation of RS results in insignificant differences from conventional approaches based on the hypothesis of isotropic mechanical properties. It can be concluded that this result is directly linked to the fact that the {311} lattice planes typically used for RS analysis in nickel-based alloys have high multiplicity and less strong texture intensities compared with other lattice planes. It is also found that the length of the laser scan vectors determines the surface RS distribution in prisms prior to their removal from the baseplate. On removal from the baseplate the surface RS considerably relaxes and/or redistributes; a combination of the geometry and the scanning strategy dictates the sub-surface RS distribution.
Journal of Applied Crystallography
10.1107/S1600576723004855
1600-5767
urn:nbn:de:kobv:b43-578331
publish
14.08.2023
Creative Commons - CC BY - Namensnennung 4.0 International
Jakob Schröder
Alexander Evans
V. Luzin
G. Abreu Faria
Sebastian Degener
E. Polatidis
J. Čapek
Arne Kromm
G. Dovzhenko
Giovanni Bruno
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Electron backscattered diffraction
eng
uncontrolled
Principal stress
eng
uncontrolled
Residual stress
Analytische Chemie
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.1 Materialographie, Fraktographie und Alterung technischer Werkstoffe
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
9 Komponentensicherheit
9.4 Integrität von Schweißverbindungen
Material
Chemie und Prozesstechnik
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
9.6 Additive Fertigung metallischer Komponenten
Additive Fertigung
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/57833/xx5022.pdf
57807
2023
eng
lecture
0
--
--
--
Influence of microstructure and residual stress state on the fatigue behaviour of a PBF-LB/M AlSi10Mg alloy
The high cooling rates (~106 K/s) occurring during Laser Powder Bed Fusion (PBF-LB/M) of AlSi10Mg induce to the formation of a fine nanometric silicon network in the as-built condition. Such unprecedented microstructure enhances the mechanical strength when compared to equivalent as-cast materials. Nevertheless, PBF-LB/M also leads to high magnitude residual stress (RS) due to the extreme localized temperature gradients. The presence of RS can be detrimental to the fatigue life of engineering components, and great efforts are focused on understanding their generation and evolution after post-process heat treatments. Typically, T6 heat treatments are used to mitigate RS and improve mechanical performances by Mg2Si precipitation during ageing at 160-180°C. Nevertheless, the solutionizing at 500-540°C vanishes the fine silicon network, leading to the formation of micrometric (average of ~2-5 µm) polygonal Si particles, similar to those observed in T6 heat-treated Al-Si cast materials. Therefore, the aim of this work is to evaluate the ability of two so-called low temperature heat treatments (i.e., at 265°C and 300°C) to mitigate RS while retaining the fine as-built microstructure inherent to PBF-LB/M AlSi10Mg. The fatigue behavior of the as-built material is subsequently compared to the two low temperature conditions.
LightMat 2023
Trondheim, Norway
21.06.2023
23.06.2023
publish
0
Itziar Serrano Munoz
eng
uncontrolled
AlSi10Mg
eng
uncontrolled
Fatigue crack propagation
eng
uncontrolled
Residual stress
eng
uncontrolled
Post processing heat treatment
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
9 Komponentensicherheit
9.4 Integrität von Schweißverbindungen
Material
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
9.0 Abteilungsleitung und andere
Additive Fertigung
57808
2023
eng
lecture
0
--
--
--
3D imaging and residual stress analysis for AM Materials
Metal Additive Manufacturing (AM) technologies such as Laser Powder Bed Fusion (LPBF) are characterized by layer wise construction, which enable advancements of component design, leading to potential efficiency and performance improvements. However, the rapid cooling rates associated with the process consequently leads to the generation of high magnitude residual stresses (RS). Therefore, a deep understanding of the formation of RS, the influence of process parameters on their magnitude and the impact on mechanical performance is crucial for widespread application. The experimental characterization of these RS is essential for safety related engineering application and supporting the development of reliable numerical models. Diffraction-based methods for RS analysis using high energy synchrotron X-rays and neutrons enable non-destructive spatially resolved characterization of both surface and bulk residual stresses in complex components. This presentation will provide an overview of recent research conducted by the BAM at large scale facilities for the characterization of residual stresses in LPBF metallic alloys. Special focus will be given to the challenges posed by textured LPBF materials for the reliable choice of the diffraction elastic constants (DECs), which is crucial to the accurate calculation of the level of RS.
Seminar at LTDS, Ecole Centrale de Lyon
Lyon, France
15.06.2023
15.06.2023
publish
false
true
0
Itziar Serrano Munoz
eng
uncontrolled
Residual stress
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Diffraction methods
Ingenieurwissenschaften und zugeordnete Tätigkeiten
8 Zerstörungsfreie Prüfung
8.5 Röntgenbildgebung
Material
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
57691
2023
eng
lecture
0
--
--
--
Consideration of manufacturing-related stresses and cold crack avoidance in high-strength steels WAAM components
High-strength steels offer great potential in weight-optimised modern steel structures. Additive manufacturing processes, such as Wire Arc Additive Manufacturing (WAAM), enable near-net-shape manufacturing of complex structures and more efficient manufacturing, offering significant savings in costs, time, and resources. Suitable filler materials for WAAM are already commercially available. However, the lack of knowledge or technical guidelines regarding welding residual stresses during manufacturing and operation in connection with cold cracking risk limit their industrial application significantly. In a project of BAM and TU Chemnitz, the influences and complex interactions of material, manufacturing process, design and processing steps on residual stress evolution are investigated. By developing process recommendations and a special cold cracking test, economic manufacturing, and stress-appropriate design of high-strength steel WAAM components are main objectives.
The present study focuses on determining the influence of heat control (interpass temperature, heat input, cooling time) and the design aspects of the components on the hardness and residual stresses, which are analysed by X-ray diffraction. Defined reference specimens, i.e., hollow cuboids, are automatically welded with a special WAAM solid wire. The influences of wall length, wall thickness and wall height on the residual stresses are analysed. Geometric properties can be selectively adjusted by wire feed and welding speed but cannot be varied arbitrarily. This was addressed by adapted build-up strategies. The results indicate a significant influence of the heat control and the wall height on the residual stresses. The interpass temperature, wall thickness and wall length are not significant. These analyses allow recommendations for standards and manufacturing guidelines, enabling a safe and economic manufacturing of high-strength steel components.
European Steel Technology and Application Days
Düsseldorf, Germany
14.06.2023
publish
false
true
0
Karsten Wandtke
eng
uncontrolled
DED-arc
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
Heat control
eng
uncontrolled
High-strength filler metals
eng
uncontrolled
Residual stress
Ingenieurwissenschaften und zugeordnete Tätigkeiten
Angewandte Physik
9 Komponentensicherheit
9.2 Versuchsanlagen und Prüftechnik
9.4 Integrität von Schweißverbindungen
Energie
Material
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
Additive Fertigung
57269
2023
eng
987
996
4
67
article
Springer
Berlin
1
--
--
--
Influence of the WAAM process and design aspects on residual stresses in high-strength structural steels
Wire arc additive manufacturing (WAAM) enables the efficient production of weight-optimized modern engineering structures. Further increases in efficiency can be achieved by using high-strength structural steels. Commercial welding consumables for WAAM are already available on the market. Lack of knowledge and guidelines regarding welding residual stress and component safety during production and operation leads to severely limited use for industry applications. The sensitive microstructure of high-strength steels carries a high risk of cold cracking; therefore, residual stresses play a crucial role. For this reason, the influences of the material, the WAAM process, and the design on the formation of residual stresses and the risk of cold cracking are being investigated. The material used has a yield strength of over 800 MPa. This strength is adjusted via solid solution strengthening and a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on the residual stresses. The focus of the present investigation is on the additive welding parameters and component design on their influence on hardness and residual stresses, which are analyzed by means of X-ray diffraction (XRD). Reference specimens (hollow cuboids) are welded fully automated with a systematic variation of heat control and design. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. Increased heat input leads to lower tensile residual stresses which causes unfavorable microstructure and mechanical properties. The component design affects heat dissipation conditions and the intensity of restraint during welding and has a significant influence on the residual stress.
Welding in the World
1878-6669
10.1007/s40194-023-01503-9
urn:nbn:de:kobv:b43-572698
publish
05.04.2023
1
Creative Commons - CC BY - Namensnennung 4.0 International
Karsten Wandtke
Dirk Schröpfer
R. Scharf-Wildenhain
A. Hälsig
Thomas Kannengießer
Arne Kromm
J. Hensel
eng
uncontrolled
DED-arc
eng
uncontrolled
Additive manufacturing
eng
uncontrolled
High-strength steel filler metal
eng
uncontrolled
Residual stress
Ingenieurwissenschaften und zugeordnete Tätigkeiten
Angewandte Physik
9 Komponentensicherheit
9.2 Versuchsanlagen und Prüftechnik
9.4 Integrität von Schweißverbindungen
Energie
Material
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
Wissenschaftliche Artikel der BAM
Additive Fertigung
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/57269/Wandtke2023_Article_WAAM process and design aspects.pdf