TY - JOUR A1 - Schempp, Philipp A1 - Cross, C.E. A1 - Pittner, Andreas A1 - Oder, Gabriele A1 - Neumann, R. S. A1 - Rooch, Heidemarie A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Rethmeier, Michael T1 - Solidification of GTA aluminium weld metal: Part I - Grain morphology dependent upon alloy composition and grain refiner content N2 - The solidification conditions during welding strongly influence the weid metal microstructure and mechanical properties of a weid. In the first part of this study, the grain morphology of gas tungsten arc (GTA) bead-on-plate welds was investigated for the aluminum Alloys 1050A (Al 99.5), 6082 (Al SifMgMn), and 5083 (AI Mg4.5Mn0.7). The experiments revealed that increasing welding speed and alloy content allow the growth of small, equiaxed grains, particularly in the weid center. Furthermore, increasing grain refiner additions led to a Strong reduction of the weid metal mean grain size and hence facilitated the columnar to equiaxed transition (CET). In addition, wavelength dispersive X-ray spectroscopy (WDS) and transmission electron microscopy (TEM) analysis revealed in the weid metal TiB2 particles that were surrounded by Al3Ti. This suggests the duplex nucleation theory for nucleation of aluminum grains in GTA weid metal. KW - Aluminium KW - Gas tungsten arc welding (GTAW) KW - Grain refinement KW - Columnar to equiaxed transition (CET) KW - Epitaxial nucleation KW - Duplex nucleation theory PY - 2014 SN - 0043-2296 SN - 0096-7629 VL - 93 SP - 53-s EP - 59-s PB - American Welding Society CY - New York, NY AN - OPUS4-30413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Adaptive manufacturing strategies for DED-Arc: Case studies on high-strength aluminium alloys and gas-turbine blade repair N2 - In this presentation, we showcase BAM’s current research activities on DED-Arc/M processes, covering both the manufacture of novel high-strength aluminium alloys and the development of automated repair strategies for gas turbine blades, with a focus on robust process control and repeatable component quality. T2 - 12. Wissenschaftliches Kolloquium im Rahmen des SFB/TRR 375 "Multifunktionale Hochleistungskomponenten aus hybriden porösen Materialien" CY - Online meeting DA - 05.02.2026 KW - DED-Arc KW - Automation KW - Quality assessment PY - 2026 AN - OPUS4-65472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Javaheri, E. A1 - Pittner, Andreas A1 - Graf, B. A1 - Rethmeier, Michael T1 - Mechanical properties characterization of reisstance spot welded DP1000 steel under uniaxial tensile tests N2 - Resistance spot welding (RSW) is widely used in the automotive industry as the main joining method. Generally, an automotive body contains around 2000 to 5000 spot welds. Therefore, it is of decisive importance to characterize the mechanical properties of these areas for the further optimization and improvement of an automotive body structure. The present paper aims to introduce a novel method to investigate the mechanical properties and microstructure of the resistance spot weldment of DP1000 sheet steel. In this method, the microstructure of RSW of two sheets was reproduced on one sheet and on a bigger area by changing of the welding parameters, e. g. welding current, welding time, electrode force and type. Then, tensile tests in combination with digital Image correlation (DIC) measurement were performed on the notched tensile specimens to determine the mechanical properties of the weld metal. The notch must be made on the welded tensile specimen to force the fracture and elongation on the weld metal, enabling the characterization of its properties. Additionally, the parameters of a nonlinear isotropic material model can be obtained and verified by the simulation of the tensile specimens. The parameters obtained show that the strength of DP1000 steel and the velocity of dislocations for reaching the Maximum value of strain hardening, are significantly increased after RSW. The effect of sample geometry and microstructural inhomogeneity of the welded joint on the constitutive property of the weld metal are presented and discussed. KW - Mechanical properties KW - resistance spot welding KW - dual phase steel KW - digital image correlation PY - 2019 VL - 61 IS - 6 SP - 527 EP - 532 PB - Carl Hanser Verlag CY - München AN - OPUS4-48296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Datei- und zugehörige Qualitätsstandard für Forschungsdaten im Bereich Schweißtechnik N2 - Ziel des WelDX Forschungsvorhabens ist es, den Austausch wissenschaftlicher Forschungsdaten aus dem Bereich der Schweißtechnik auf Basis eines einheitlichen Open Source Dateiformates zu ermöglichen und damit die Einhaltung und Dokumentation geeigneter Qualitätsstandards zu fördern. Im Zuge der Projektarbeit wird die Zusammenarbeit und der Wissenstransfer schweißtechnischer Institute zunächst auf nationaler Ebene gefördert und die Bildung eines von der Fachcommunity getragenen Kuratoriums zur Betreuung und Weiterentwicklung des Dateiformates und der Ausarbeitung zugehöriger Qualitätsstandards angestrebt. Zunächst erfolgt die Erstellung und Veröffentlichung eines geeigneten Dateiformates zum Austausch großvolumiger, detaillierter Forschungsdaten im Bereich mechanisierter und automatisierter Schweißverfahren. Durch die Nutzung des Dateiformates zur Dokumentation der Forschungsarbeiten soll auch für komplexe Schweißaufgaben und Versuchsaufbauten eine deutlich gesteigerte objektive Vergleichbarkeit der Messdaten und Ergebnisse im Sinne der guten wissenschaftlichen Praxis zwischen den Instituten erzielt werden. T2 - Vernetzungsveranstaltung zu „Kurationskriterien und Qualitätsstandards von Forschungsdaten“ CY - Berlin, Germany DA - 26.09.2019 KW - Schweißen KW - Forschungsdatenmanagement KW - Open science KW - Open data KW - Digitalisierung PY - 2019 AN - OPUS4-49385 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Automatically Welded Tubular X-Joints - Welding Procedure and Prediction of the Technical Fatigue Crack Location N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper ad-dresses the welding process of automated manufactured tubular X-joints. Additionally, fatigue tests of the automatically welded tubular joints are presented focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch con-sidering the structural stress approach as well as the notch stress ap-proach. T2 - 29th International Ocean and Polar Engineering Conference CY - Honolulu, Hawaii, USA DA - 16.06.2019 KW - Notch stress approach KW - Tubular X-joints KW - Automated manufacturing KW - Fatigue tests KW - Structural stress approach PY - 2019 SN - 978-1-880653-85-2 SP - 4098 EP - 4105 AN - OPUS4-51848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Prediction of the Initial Fatigue Crack Location of Automatically Welded Tubular Joints for Jacket Support Structures N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints com-bined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatical-ly welded tubular X-joints focusing on the location of the technical fatigue crack. For this X-joint, the detect-ed location of the technical crack is then compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Additionally, the fatigue prone hot spot according to both approaches is compared for a typical offshore jacket double-K-joint to emphasize the significance of the presented outcomes for the existing offshore structures. Besides, the welding process of the automated manufactured tubular X-joints is presented. T2 - 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC) CY - Cape Town, SOUTH AFRICA DA - 02.09.2019 KW - Lightweight Design KW - Jacket Support Structures KW - Arc Welding Automation KW - Fatigue KW - Offshore Wind PY - 2019 SN - 978-1-138-38696-9 DO - https://doi.org/10.1201/9780429426506-100 VL - 2019 SP - 575 EP - 580 AN - OPUS4-51847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Automatically Welded Tubular X Joints for Jacket Substructures – Prediction of the Technical Fatigue Crack Location N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented. T2 - Nordic Steel 2019 CY - Copenhagen, Denmark DA - 18.09.2019 KW - Automated arc welding KW - Fatigue tests KW - Tubular X-joints KW - Technical crack detection KW - Local fatigue approaches PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518490 DO - https://doi.org/10.1002/cepa.1140 VL - 3 IS - 3-4 SP - 823 EP - 828 PB - Wiley-VCH Verlag GmbH on behalf of Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-51849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Häberle, Nicolas A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Abschlusspräsentation SimCoLas Verbundprojekt -- Arbeitspakete BAM N2 - Die Präsentation gibt einen Überblick bezüglich der von der BAM im Rahmen des SimCoLas Verbundprojekts durchgeführten Arbeiten zum Thema "Photonische Prozessketten". Die numerisch abgebildete Prozesskette Tiefziehen/Laserstrahlschweißen wird darsgestellt und diskutiert. Fokus der Diskussion ist die entwickelte Methodik zur konsistenten Abbildung numerischer Prozessketten mit der Applikation Heissrisskritikalität beim Laserstrahlschweißen. T2 - Verbundprojekt SimCoLas Abschlusstreffen CY - Robert Bosch GmbH Corporate Research Centre, Renningen bei Stuttgart, Germany DA - 13.06.2019 KW - Laserstrahlschweißen KW - Heissrisse KW - Prozesskette PY - 2019 AN - OPUS4-50033 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Häberle, Nicolas A1 - Pittner, Andreas T1 - Numerische Heissrissprognose in photonischen Prozessketten - Ein Zwischenbericht N2 - Der Vortrag gibt einen Überblick über Arbeiten im Rahmen der Themenstellung "photonische Prozessketten" des SimCoLas Projekts. Es werden Ergebnisse zur Datendurchgängigkeit der Prozesskette Umformen/Laserstrahlschweißen sowie erste Ergebnisse zu numerischen Schweißstruktursimulationen zur Bewertung der Heissrisskritikalität eines tiefgezogenen Napfes beim Laserstrahlschweißen gegeben. T2 - Projekttreffen des SimCoLas Verbundprojekts im Februar 2019 CY - Wolfsburg, Germany DA - 14.02.2019 KW - Laserstrahlschweißen KW - Numerische Simulation KW - Prozesskette KW - SimCoLas PY - 2019 AN - OPUS4-50031 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Pelkner, Matthias A1 - Lyamkin, Viktor A1 - Pittner, Andreas A1 - Werner, Daniel A1 - Wimpory, R. A1 - Boin, M. A1 - Kreutzbruck, Marc A1 - Bruno, Giovanni T1 - Influence of the microstructure on magnetic stray fields of low-carbon steel welds N2 - This study examines the relationship between the magnetic mesostructure with the microstructure of low carbon steel tungsten inert gas welds. Optical microscopy revealed variation in the microstructure of the parent material, in the heat affected and fusion zones, correlating with distinctive changes in the local magnetic stray fields measured with high spatial resolution giant magneto resistance sensors. In the vicinity of the heat affected zone high residual stresses were found using neutron diffraction. Notably, the gradients of von Mises stress and triaxial magnetic stray field modulus follow the same tendency transverse to the weld. In contrast, micro-X-ray fluorescence characterization indicated that local changes in element composition had no independent effect on magnetic stray fields. KW - TIG-welding KW - GMR sensors KW - Magnetic stray field KW - Neutron diffraction KW - Residual stress KW - Microstructure KW - Low carbon steel PY - 2018 DO - https://doi.org/10.1007/s10921-018-0522-0 SN - 0195-9298 SN - 1573-4862 VL - 37 IS - 3 SP - 66,1 EP - 18 PB - Springer US CY - New York AN - OPUS4-45855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Javaheri, E. A1 - Pittner, Andreas A1 - Graf, B. A1 - Rethmeier, Michael T1 - Instrumented indentation technique and its application for the determination of local material properties of welded steel structures N2 - The determination of mechanical properties of welded Steel structures such as strength or ductility is a subject of high interest for the majority of Companies in the area of metal Processing. The material Parameters can be obtained by performing the tensile test on the samples made from a part of a component. In some cases, it is highly expensive to produce the tensile specimens especially from the weld metal, which contains different type of microstructure such as weld seam or heat affected zone in an extremely small area. Therefore, a method is described in this paper to determine the material Parameters of high strength Steel structures and welded joints locally and without any additional effort to perform the tensile test. In this method, instrumented indentation technique (IIT), an indenter is pushed on the flat surface of a specimen in a certain period of time and simultaneously the applied force and the corresponding indentation path are measured. The data related to the force-indentation diagram is given as input to an artificial neural network (ANN) to obtain the material Parameters. The ANN can be trained by generating the large qualitative data sets with numerical Simulation of the IIT procedure. The Simulation must be run several times with the different material model parameter sets to generate the numerous force-indentation diagrams as the inputs of ANN. Then, the trained ANN is validated by performing the IIT on the welded joints and comparing the obtained material Parameters from ANN with the tensile test. Consequently, the mechanical properties of welded joints can be determined by performing the IIT and evaluating the resulting data by the ANN. T2 - 39. Assistentenseminar CY - Eupen, Germany DA - 12.09.2018 KW - Steel PY - 2019 SN - 978-396144-070-2 SP - 146 EP - 152 PB - DVS Media GmbH AN - OPUS4-51317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Lyamkin, V. A1 - Bruno, Giovanni A1 - Pittner, Andreas A1 - Wimpory, Robert A1 - Boin, M. A1 - Kreutzbruck, Marc T1 - Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings N2 - The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction(ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth. KW - GMR KW - Magnetic stray field KW - Neutron diffraction KW - Residual stress KW - TIG-welding PY - 2017 DO - https://doi.org/10.1016/j.jmmm.2016.11.102 SN - 0304-8853 SN - 1873-4766 VL - 426 SP - 580 EP - 587 PB - Elsevier CY - Amsterdam AN - OPUS4-38678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Automatically Welded Tubular X-Joints for Jacket Substructures N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented. KW - Tubular X-joints KW - Fatigue tests KW - Technical crack detection KW - Local fatigue spproaches PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513228 DO - https://doi.org/10.1002/cepa.1140 VL - 3 IS - 3-4 SP - 823 EP - 828 PB - Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-51322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Wire arc additive manufacturing of high strength AL-MG-SI alloys N2 - Gas metal arc-based direct energy deposition (DED) additive manufacturing technologies hold significant promise for producing large-scale metal components. However, determining optimal process parameters to achieve the desired near-net shape design and mechanical performance is a complex challenge due to the intricate interplay between process parameters and material properties. This presentation highlights the use of a newly developed solid welding wire doped with TiB to improve grain refinement in metals deposited via DED-Arc for high-strength precipitation-hardening AlMgSi aluminum alloys. This wire stems from our initial metallurgical investigations into grain refinement in aluminum weld metals. The research emphasizes the relationship between process parameters and component quality, aiming to uncover the mechanisms that influence performance. This is essential for establishing a reliable range of parameters that meet quality standards, many of which are derived from traditional welding practices. Component quality was assessed by studying pore size, pore distribution, and grain morphology. To further enhance the mechanical properties of the deposited material, post-weld heat treatments—including solution treatment, quenching, and artificial aging—were applied. The study also explores how different heat treatment strategies affect the final mechanical properties. To validate the feasibility of 3D printing high-strength aluminum alloys, a more complex demonstrator component was fabricated. The results demonstrate that DED-Arc technology can produce large aluminum parts with a quality comparable to subtractive manufacturing techniques. Furthermore, the entire additive manufacturing workflow has been digitally integrated, enabling full traceability of all key process steps. This digital integration is critical for ensuring reliable quality assessments of the finished components. T2 - 77th IIW Annual Assembly and International Conference Joint Meeting of C-I, C-IV, and C-XII CY - Rhodos, Greece DA - 07.07.2024 KW - DED-Arc KW - High-strength aluminium alloys KW - Porosity assessment KW - Component testing KW - CT-analyses PY - 2024 AN - OPUS4-62014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -