TY - CONF A1 - Böllinghaus, Thomas A1 - Holler, K. A1 - Kannengießer, Thomas A1 - Schobbert, H. T1 - Nd: YAG laser plasma powder hybrid welding of austenitic stainless steels N2 - As an approach towards more rough industrial laser welding applications, the Nd:YAG laser welding process has been coupled to the plasma powder welding process for the first time. Process stabilities have been achieved by such hybrid welding which are even better than those known from previous coupling of the laser process with gas metal arc welding (GMAW), for instance. The present contribution focuses on the technology and potentials of the novel laser hybrid welding technique and addresses the realisation and the perspectives for practical applications. The experimental results demonstrate that the new process coupling enables welding of austenitic stainless steels in the thickness range between 3 mm and 8 mm at various weld geometries and joint configurations and at welding speeds exceeding 2 m/min. In addition it has been proven that the laser plasma powder arc welding (LPPAW) technique can also be applied to out-of-position conditions. Continuous advancement of the welding equipment ensures a high gap bridging ability and levelling of misalignment due to higher powder feeding rates. The recent development of a new plasma powder torch even provides a higher efficiency of powder feeding and guarantees smoth weld surfaces. Up to the present, the investigations demonstrated that the novel laser plasma powder hybrid welding technique offers all perspectives for application in pipe fabrication, ship building and offshore as well as transportation industry. T2 - Seminar in Mechanical and Metallurgical Approaches to New Joining Process CY - Awaji Island, Japan DA - 20.07.2004 KW - Nd:YAG KW - Laser plasma KW - Powder KW - Hybrid KW - Welding KW - Austenitic stainless steels PY - 2004 SP - 140 EP - 145 CY - Japan AN - OPUS4-39261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dixneit, Jonny A1 - Kromm, Arne A1 - Hannemann, Andreas A1 - Friedersdorf, Peter A1 - Kannengießer, Thomas A1 - Gibmeier, J. T1 - In-situ load analysis in multi-run welding using LTT filler materials N2 - Modifying the level of mostly detrimental welding residual stresses already during the welding process would be highly attractive as time- and cost-consuming post processing may be prevented. The nature of stress buildup during welding-associated cooling is highly affected by phase transformations. Up to now, it is not clear in which way this is applicable to real component welding exhibiting high shrinkage restraint and complex heat input. In this study, two different low transformation temperature (LTT) alloys have been investigated concerning the stress development in restrained multi-run butt welding in order to evaluate the potential of stress reduction. Pulsed gas metal arc welding (P-GMAW) welding was executed on a testing facility designed to simulate real lifelike restraint conditions of component weldments. The effect of reducedMS-temperatures and the heat control on the globally acting stresses was monitored by in-situ measurement of the reaction forces during welding fabrication. Additional local residual stress measurements allowed analyzing global as well as local loading of the welded construction. Although phase transformation has a significant influence on unloading the joint during each weld pass, the reaction stress upon cooling to room temperature seems to be determined mainly by the heat input. On the surface, low longitudinal residual stresses were observed in case of LTT whereas transverse residual stresses are less affected. T2 - 69th IIW Annual Assembly and International Conference CY - Melbourne, Australia DA - 10.07.2016 KW - Phase transformation temperature KW - Residual stress KW - Welding KW - Dilution KW - Restraint PY - 2016 U6 - https://doi.org/10.1007/s40194-016-0373-1 SN - 0043-2288 VL - 60 IS - 6 SP - 1159 EP - 1168 PB - Springer CY - Heidelberg AN - OPUS4-37892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kannengießer, Thomas A1 - Kromm, Arne A1 - Schröpfer, Dirk A1 - Lausch, T. T1 - Issues and challenges in component welding of high strength fine-grained structural steels N2 - When assessing the performance of welded components residual stresses are vital. The possibilities of transferring the real boundary conditions of welding, which influence the residual stress, into the laboratory are highlighted in this contribution. The potentials of a test system specially developed for this purpose are demonstrated. The component design induces global process-, geometry- and material-dependent stresses, which can be simulated and quantified in the system. In addition, the resulting local residual stress distribution can be exactly determined with high spatial resolution with the aid of X-ray diffraction. Examples are presented of how the conditions to be found during production are simulated in the laboratory. T2 - AJP 2019 CY - Ponta Delgada, Azores (Portugal) DA - 24.10.2019 KW - Residual stress KW - Welding KW - X-ray diffraction KW - Creep-resistant steel KW - Large-scale test PY - 2019 AN - OPUS4-50036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kannengießer, Thomas A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schroepfer, Dirk T1 - In-situ Observation of Stress Evolution during High Strength Steel Welding N2 - Residual stresses are crucial when assessing the performance of welded components. The present work deals with the possibilities of transferring the real-life boundary conditions of welding, which influence the residual stress, into the laboratory. The possibilities of a test system with a load capacity of 2 MN specifically developed for online monitoring of stress formation and cracking are shown. Due to the structural design, global process, geometry and material-dependent stresses are induced, which can be quantified in-situ during welding and post weld heat treatment. Examples are presented how the conditions to be found during production are simulated in the laboratory. It is shown how welding residual stresses in high-strength steels are affected by the heat control. Elevated working temperatures significantly increase the tensile residual stresses in the heat affected zone (HAZ). The effect of mechanical stresses resulting from welding on stress relief cracking is demonstrated by the example of a creep resistant steel. Reheat cracks were monitored online during post weld heat treatment. T2 - Visual-JW 2019 & WSE 2019 The 5th International Symposium on Visualization in Joining & Welding Science through Advanced Measurements and Simulation & The 8th International Conference of Welding Science and Engineering CY - Osaka, Japan DA - 21.11.2019 KW - Residual stress KW - Restraint KW - Welding KW - Large-scale test KW - Reheat cracking PY - 2019 AN - OPUS4-49763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kannengießer, Thomas A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schroepfer, Dirk A1 - Hannemann, Andreas T1 - In-situ Observation of Stress Evolution and Cracking during High Strength Steel Welding N2 - Residual stresses are crucial when assessing the performance of welded components. The present work deals with the possibilities of transferring the real-life boundary conditions of welding, which influence the residual stress, into the laboratory. The possibilities of a test system with a load capacity of 2 MN specifically developed for online monitoring of stress formation and cracking are shown. Due to the structural design, global process, geometry and material-dependent stresses are induced, which can be quantified in-situ during welding and post weld heat treatment. Examples are presented how the conditions to be found during production are simulated in the laboratory. It is shown how welding residual stresses in high-strength steels are affected by the heat control. Elevated working temperatures significantly increase the tensile residual stresses in the heat affected zone (HAZ). The effect of mechanical stresses resulting from welding on stress relief cracking is demonstrated by the example of a creep resistant steel. Reheat cracks were monitored online during post weld heat treatment. T2 - Visual-JW 2019 & WSE 2019 The 5th International Symposium on Visualization in Joining & Welding Science through Advanced Measurements and Simulation & The 8th International Conference of Welding Science and Engineering CY - Osaka, Japan DA - 21.11.2019 KW - Residual stress KW - Restraint KW - Welding KW - Large-scale test KW - Reheat cracking PY - 2019 SP - 83 EP - 84 PB - SEIEI Printing Co., Ltd CY - Osaka, Japan AN - OPUS4-49773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schröpfer, Dirk A1 - Dixneit, Jonny A1 - Hannemann, Andreas A1 - Kannengießer, Thomas ED - Neu, Richard W. ED - Totten, George E. T1 - From the field to the lab: Real scale assessment of stresses in welded components N2 - Residual stresses are crucial when assessing the performance of welded components. The present work deals with the possibilities of transferring the real-life boundary conditions of welding, which influence the residual stress, into the laboratory. The possibilities of a test system specifically developed for this purpose with a maximum capacity of 2 MN are shown. Due to the structural design, global process, geometry and material-dependent stresses are induced, which can be simulated and quantified within the system. Additionally, X-ray diffraction can be applied to determine the resulting local residual stress distribution precisely with high spatial resolution. Two examples are presented how the conditions to be found during production are simulated in the laboratory. It is shown how welding residual stresses in high-strength steels are affected by the heat control. It was possible to clarify why elevated working temperatures significantly increase the bending stresses in the welded joint and therefore the tensile residual stresses in the heat affected zone (HAZ). The effect of a heat treatment applied under mechanical stress resulting from welding is demonstrated by the example of a creep resistant steel. Reheat cracking is significantly increased in this case compared to small scale laboratory based tests. KW - Residual stress KW - Welding KW - Large-scale test KW - Creep resistant steel KW - High strength steel PY - 2018 U6 - https://doi.org/10.1520/MPC20170111 SN - 2379-1365 VL - 7 IS - 4 SP - 574 EP - 593 PB - ASTM International CY - West Conchohocken AN - OPUS4-46662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part I - Effect of heat control on welding stresses and stress relief cracking N2 - The avoidance of failures during the fabrication or operation of petrochemical reactors made of creep-resistant, low-alloy steels as 13CrMoV9-10 requires still research despite over 60 years of international investigations in the field of stress relief cracking. The quality of modern base materials and filler metals leads to the fact that previously known crack causes, such as impurities of S or P, recede into the background. Rather, the causes are increasingly to be found in the fabrication process. Investigations on the influence of heat control on the stresses in welded components and thus on the stress relief cracking sensitivity under realistic manufacturing conditions are not yet available. This work is subdivided in two parts. Part 1 of this study focused on the effect of heat control during submerged arc welding on the stresses. For this purpose, a testing facility was applied, which allows to observe the forces and moments accumulating during welding or heat treatment in a component-like specimen under shrinkage restraint. The stress acting in the specimen increases with higher preheat/interpass temperatures and higher heat input. During the heat treatment, the stresses are relieved. Nevertheless, cracks are formed already during heating. The total crack length correlates with the heat input. KW - Welding KW - Creep-resistant steel KW - Post weld heat treatment KW - Stress relief cracking PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-506271 SN - 1878-6669 VL - 64 IS - 5 SP - 807 EP - 817 PB - Springer CY - Berlin AN - OPUS4-50627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part II - Mechanisms of stress relief cracking during post weld heat treatment N2 - Welding of 13CrMoV9-10 vanadium steel requires care due to an increased susceptibility to stress relief cracking during post weld heat treatment. Previous research into the crack formation in creep-resistant steels has focused on thermal and metallurgical factors; however, little knowledge has been gathered regarding the crack formation during post weld heat treatment considering real-life restraint conditions. This work is subdivided in two parts. Part I showed that an increasing heat input during submerged arc welding under restraint led to an increasing stress level in the joint prior to the post weld heat treatment. The magnitude of stress relief cracking observed in the heat-affected zone after the post weld heat treatment is affected by the heat input. In Part II of this work, the cracks and the associated microstructure which occurred under restraint were studied. The application of a Special acoustic emission analysis indicated that the cracks formed in a temperature range between 300 and 500 °C during the post weld heat treatment. The toughness in the heat-affected zone of the restrained welds was affected by the welding heat input. Microstructural analyses of all specimens revealed accelerated aging due to precipitation of carbides during post weld heat treatment under restraint. KW - Welding KW - Creep-resistant steel KW - Post weld heat treatment KW - Stress relief cracking PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-506283 SN - 1878-6669 VL - 64 SP - 819 EP - 829 PB - Springer CY - Berlin AN - OPUS4-50628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne A1 - Rhode, Michael A1 - Launert, B. A1 - Dixneit, Jonny A1 - Kannengießer, Thomas A1 - Pasternak, H. ED - Olden, T.-M. ED - Muransky, O. ED - Edwards, L. T1 - Combining sectioning method and X-ray diffraction for evaluation of residual stresses in welded high strength steel components N2 - Residual stresses and distortions in welded I-girders for steel construction are relevant when evaluating the stability of steel beams and column members. The application of high strength steels allows smaller wall thicknesses compared to conventional steels. Therefore, the risk of buckling has to be considered carefully. Due to the lack of knowledge concerning the residual stresses present after welding in high strength steel components conservative assumptions of their level and distribution is typically applied. In this study I-girders made of steels showing strengths of 355 MPa and 690 MPa were welded with varying heat input. Due to the dimension of the I-girders and the complex geometry the accessibility for residual stress measurement using X-ray diffraction was limited. Therefore, saw cutting accompanied by strain gauge measurement has been used to produce smaller sections appropriate to apply X-ray diffraction. The stress relaxation measured by strain gauges has been added to residual stresses determined by X-ray diffraction to obtain the original stress level and distribution before sectioning. The combination of both techniques can produce robust residual stress values. From practical point of view afford for strain gauge application can be limited to a number of measuring positions solely to record the global amount of stress relaxation. X-ray diffraction can be applied after sectioning to determine the residual stresses with sufficient spatial resolution. T2 - ICRS 2016 - 10th International Conference on Residual Stresses CY - Sydney, Australia DA - 03.07.2016 KW - Welding KW - Residual Stress KW - Sectioning Method KW - X-Ray Diffraction KW - Component Testing PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-389206 SN - 978-1-94529117-3 SN - 978-1-94529117-6 SN - 2474-395X VL - 2 SP - 163 EP - 168 PB - Materials Research Forum LLC CY - Millersville (PA), USA AN - OPUS4-38920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Schaupp, Thomas A1 - Müller, Bernd R. A1 - Griesche, Axel A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - 3D imaging of hydrogen assisted cracking using analyser-based imaging N2 - To better understand the mechanism of hydrogen assisted cracking (HAC), it is important to investigate the 3D structure of the cracks non-destructively. Since, cracks introduced by HAC are usually very small, conventional x-ray imaging methods often lack the required spatial resolution. However, the detection of those cracks can be enhanced by taking advantage of refraction at interfaces within the sample. To image this refractive deflection we employ analyser based imaging (ABI). In this work we aim at proving the enhanced crack detection of ABI by investigating an alluminum alloy weld. T2 - BESSY User Meeting 2015 CY - Berlin, Germany DA - 09.12.2015 KW - X-ray refraction KW - Synchrotron KW - Analyser-based imaging KW - Hydrogen assisted cracking KW - Welding PY - 2015 AN - OPUS4-38278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -