TY - CONF A1 - Sproesser, G. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Increasing performance and energy efficiency of Gas Metal Arc Welding by a high power tandem process N2 - Standard Gas Metal Arc Welding (Standard GMAW) and a high power Tandem GMAW (TGMAW) process are evaluated with respect to energy efficiency. Current, voltage and overall equipment power are measured and energy consumption is determined. The new key performance indicator Electrical Deposition Efficiency is introduced to reflect the energy efficiency of GMAW processes. Additionally, wallplug efficiency of the equipment is determined in order to identify the overall energy consumption. Results show that energy efficiency as well as economic process performance can be significantly increased by application of the TGMAW process. Furthermore findings indicate that wall-plug efficiency of the equipment is independent of power level and material transfer mode. A metal plate of 30 mm thick structural steel is joined by Standard GMAW and TGMAW to demonstrate the total energy savings for a real weld. Electricity consumption is reduced by more than 20 % using the high power TGMAW process. T2 - 13th Global Conference on Sustainable Manufacturing - Decoupling Growth from Resource Use CY - Bình Dương New City, Vietnam DA - 16.09.2015 KW - Thick metal plate welding KW - Energy efficiency KW - Tandem Gas Metal Arc Welding KW - High power welding PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-353762 DO - https://doi.org/10.1016/j.procir.2016.01.148 SN - 2212-8271 VL - 40 SP - 643 EP - 648 PB - Elsevier B.V. AN - OPUS4-35376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sproesser, G. A1 - Schenker, S. A1 - Pittner, Andreas A1 - Borndörfer, R. A1 - Rethmeier, Michael A1 - Chang, Y.-J. A1 - Finkbeiner, M. T1 - Sustainable welding process selection based on weight space partitions N2 - Selecting a welding process for a given application is crucial with respect to the sustainability of part manufacturing. Unfortunately, since welding processes are evaluated by a number of criteria, preferences for one or the other process can be contradictory. However, the prevalent procedure of weight assignment for each criterion is subjective and does not provide information about the entire solution space. From the perspective of a decision maker it is important to be able to assess the entire set of possible weightings and answer the question which welding process is optimal for which set of weights. This issue is investigated by means of a weight space partitioning approach. Two welding processes are considered with respect to three criteria that reflect their economic and environmental performance. In order to find the most sustainable welding process the underlying weight space partition is evaluated. T2 - 13th Global Conference on Sustainable Manufacturing – Decoupling Growth from Resource Use CY - Bình Dương New City, Vietnam DA - 16.09.2015 KW - Welding costs KW - Multi-criteria decision support KW - LCA KW - Welding process selection KW - GMAW KW - Multi-attribute decision method PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-353740 DO - https://doi.org/10.1016/j.procir.2016.01.077 SN - 2212-8271 VL - 40 SP - 127 EP - 132 PB - Elsevier B.V. AN - OPUS4-35374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gebhardt, M.O. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Numerical analysis of hot cracking in laser-hybrid welded tubes N2 - In welding experiments conducted on heavy wall pipes, the penetration mode (full or partial penetration) occurred to be a significant factor influencing appearance of solidification cracks. To explain the observed phenomena and support further optimization of manufacturing processes, a computational model was developed, which used a sophisticated strategy to model the material. High stresses emerged in the models in regions which showed cracking during experiments. In partial penetration welding, they were caused by the prevention of weld shrinkage due to the cold and strong material below the joint. Another identified factor having an influence on high stress localization is bulging of the weld. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302961 DO - https://doi.org/10.1155/2013/520786 SN - 1687-8442 SN - 1687-8434 IS - Article ID 520786 SP - 1 EP - 8 PB - Hindawi Publishing Corporation CY - New York, NY, USA AN - OPUS4-30296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Experimental and numerical investigation of an electromagnetic weld pool control for laser beam welding N2 - The objective of this study was to investigate the influence of externally applied magnetic fields on the weld quality in laser beam welding. The optimization of the process parameters was performed using the results of computer simulations. Welding tests were performed with up to 20 kW laser beam power. It was shown that the AC magnet with 3 kW power supply allows for a prevention of the gravity drop-out for full penetration welding of 20 mm thick stainless steel plates. For partial penetration welding it was shown that an0.5 T DC magnetic field is enough for a suppression of convective flows in the weld pool. Partial penetration welding tests with 4 kW beam power showed that the application of AC magnetic fields can reduce weld porosity by a factor of 10 compared to the reference joints. The weld surface roughness was improved by 50%. KW - Laser beam welding KW - Electromagnetic weld pool support KW - Hartmann effect KW - Electromagnetic rectification PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314405 DO - https://doi.org/10.1016/j.phpro.2014.08.006 SN - 1875-3892 VL - 56 SP - 515 EP - 524 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-31440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jonietz, Florian A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Suwala, H. A1 - Rethmeier, Michael T1 - Untersuchung von Punktschweißverbindungen mit aktiver Thermografie N2 - Widerstandspunktschweißen ist insbesondere im Automobilbau eine der wichtigsten Fügetechniken. Bislang erfolgt die Qualitätssicherung überwiegend durch stichprobenartige zerstörende Prüfung. Eine zerstörungsfreie Prüftechnik würde neben der Reduzierung der Prüfkosten auch eine Optimierung des Punktschweißverfahrens bedeuten, da prinzipiell jeder Schweißpunkt geprüft werden könnte und somit auch eine Reduzierung der Anzahl der Schweißpunkte möglich ist. Es wird ein Verfahren vorgestellt, bei dem die Punktschweißverbindung zwischen zwei Stahlblechen optisch auf einer Blechseite mittels Laser oder Blitzlicht erwärmt wird. Die aufgeschmolzene Zone, die sogenannte Schweißlinse, stellt dabei neben der mechanischen Verbindung auch eine Wärmebrücke zwischen den beiden verschweißten Blechen dar, die bei diesem Verfahren ausgenutzt wird. Durch den verbesserten thermischen Kontakt zwischen den verschweißten Blechen an der Schweißlinse kontrastiert diese deutlich mit dem umgebenden Blechmaterial, bei dem der Wärmeübertrag zwischen den Blechen vergleichsweise gering ist. Dieser Kontrast im thermischen Verhalten kann mittels zeitabhängiger Thermografie gemessen werden. Durch das hier vorgestellte Verfahren kann mittels aktiver Thermografie sowohl in Transmissions- als auch in Reflexionsanordnung die Größe des thermischen Kontaktes zwischen den beiden Blechen ermittelt werden, welche ein Maß für die Größe der Schweißlinse und damit für die qualitative Güte der Schweißung darstellt. Ein Vorteil des entwickelten Verfahrens ist seine Anwendbarkeit auf Bleche ohne Oberflächenbehandlung. T2 - DACH-Jahrestagung 2015 CY - Salzburg, Austria DA - 11.05.2015 PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343476 UR - http://www.ndt.net/?id=19068 SN - 1435-4934 VL - 21 IS - 4 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-34347 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Sproesser, G. A1 - Change, Y.-J. A1 - Pittner, Andreas A1 - Finkbeiner, M. A1 - Rethmeier, Michael ED - Stark, R. ED - Bonvoisin, J. ED - Seliger, G. T1 - Sustainable technologies for thick metal plate welding N2 - Welding is the most important joining technology. In the steel construction industry, e.g. production of windmill sections, welding accounts for a main part of the manufacturing costs and resource consumption. Moreover, social issues attached to welding involve working in dangerous environments. This aspect has unfortunately been neglected so far, in light of a predominant focus on economics combined with a lack of suitable assessment methods. In this chapter, exemplary welding processes are presented that reduce the environmental and social impacts of thick metal plate welding. Social and environmental Life Cycle Assessments for a thick metal plate joint are conducted for the purpose of expressing and analysing the social and environmental impacts of welding. Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase social and environmental performance in contrast to common technologies, and therefore offer great potential for sustainable manufacturing. KW - Human health G. KW - Life cycle assessment (LCA) KW - Arc welding KW - Laser arc-hybrid welding KW - Resource efficiency KW - Social life cycle assessment (SLCA) PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390025 SN - 978-3-319-48513-3 SN - 978-3-319-48514-0 DO - https://doi.org/10.1007/978-3-319-48514-0 SN - 2194-0541 SN - 2194-055X SP - 71 EP - 84 PB - Springer CY - Cham, Switzerland AN - OPUS4-39002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quiroz Penaranda, Vanessa A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Laser beam weldability of high-manganese austenitic and duplex stainless steel sheets N2 - Manganese alloyed stainless steels represent a cost-effective alternative to conventional CrNi- stainless steels due to strong fluctuations of the market prices for nickel seen during the last years. In CrMnNi steels, nickel is partially replaced by lower-cost manganese and small amounts of nitrogen for stabilization of the austenitic phase. This also brings benefits regarding the mechanical properties, as it results in an increased material strength. Laser beam welding of such materials was investigated for direct comparison with standard CrNi steels. Main emphasis was laid on finding adequate process parameters to achieve a stable welding process and obtain a good weld quality. Two different laser sources, a 4.4 kW Nd:YAG and a 5 kW CO2 laser, were used to weld 1.5 mm stainless steel sheets in continuous wave mode. A high-Mn austenitic (1.4376) and a lean duplex (1.4162) steel, as well as the standard austenitic (1.4301) and duplex (1.4362) grades were selected as test materials. Both butt and lap joint configurations were studied. Experiments were carried out systematically, varying the welding speed, laser power and focal point position in order to determine adequate process windows. The influence of the shielding gas type and flow rate on the process stability and the weld quality were investigated. The effects of weld edge preparation on the weld appearance and quality levels attained were also examined. The obtained welded joints were subjected to radiographic tests for detection of internal imperfections. Also a metallurgical characterization of the samples regarding the resulting phase composition or balance and hardness depending on the welding process parameters was conducted. Furthermore, tensile and potentiodynamic tests were performed to evaluate the mechanical and corrosion properties, respectively. The results provide an insight into the advantages and limitations of the laser beam welding process for joining high-manganese alloyed stainless steels. Conditions for the production of defect-free and corrosion-resistant welds having good mechanical properties could be determined. KW - Austenitic stainless steels KW - Corrosion KW - CO2 lasers KW - Duplex stainless steels KW - Laser welding KW - Manganese KW - Mechanical properties KW - Shielding gases KW - YAG lasers KW - Weldability PY - 2012 SN - 0043-2288 SN - 1878-6669 VL - 56 IS - 1/2 SP - 9 EP - 20 PB - Springer CY - Oxford AN - OPUS4-25404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yang, Chunliang A1 - Yang, Fan A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Phase-field simulation of the dendrite fragmentation by electromagnetic stirring in AA5754 aluminum alloy laser beam welding N2 - A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding. Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force, without fragmentation, at the characteristic time instants. Both in the early and late stages, the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth, especially in the direction perpendicular to the solidification. The later stage fragmentation has the possibility of breaking one grain into several, which verifies the possibility of grain refinement caused by dendrite fragmentation. The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth. In addition, the cases with different initial nuclear positions were compared. The grain growth in the low-temperature zone can be inhibited by the equiaxed grains' fragmentation at the high-temperature area (179.8 μm² and 14.7 % start at the center, 115.4 μm² and 9.4 % start at the high-temperature corner, 134.3 μm² and 10.9 % start at the low-temperature corner), which is another kind of grain refinement by the dendrite fragmentation. This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’ appearance (179.8 μm² and 14.7 % when virtual grains appear at t = 4.3803 s and t = 4.3803 s, 134.3 μm² and 10.9 % at t = 4.0977 s and t = 3.9564 s, and 115.4 μm² and 9.4 % at t = 3.8151 s and t = 3.5325 s). KW - Laser beam welding KW - Electromagnetic KW - Aluminum alloys KW - Phase field method KW - Equiaxed grain KW - Dendrite fragmentation PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656610 DO - https://doi.org/10.1016/j.cwe.2025.100014 SN - 3117-4159 VL - 35 IS - 1 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-65661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Kising, Pascal A1 - Yang, Fan A1 - Rethmeier, Michael T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A conditional variational autoencoder model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-variational autoencoder model with the evidence lower bound loss function and include Kullback–Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes. KW - Laser beam welding KW - Generative artificial intelligence KW - Machine learning KW - Numerical simulation KW - Weld pool KW - Keyhole dynamics PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656621 DO - https://doi.org/10.2351/7.0001862 SN - 1042-346X VL - 38 IS - 1 SP - 1 EP - 8 PB - Laser Institute of America AN - OPUS4-65662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - Kaplan, Alexander A1 - Rethmeier, Michael T1 - Digitalisation and Carbon Footprint Evaluation of Gas Metal Arc Welding and Wire-Arc Directed Energy Deposition N2 - This paper showcases how a holistic approach to digitalisation enables data-driven welding applications, exemplarily for a gas metal arc welding (GMAW) laboratory. The workflow integrates advanced process monitoring, synchronised multi-sensor data acquisition and tools for data analytics. A welding domain-specific data exchange format weldx is presented that unifies and aggregates the data sets acquired during process monitoring with final component quality metrics, supporting reuse, traceability, and reproducibility. Two case studies illustrate the approach. First, GMAW parameters are adaptively adjusted according to local seam geometry to compensate joint-preparation deviations from nominal values typical for large-scale steel fabrication. Second, the seamless data aggregation along the welding production chain enables an automatic life-cycle assessment (LCA), quantifying the environmental impacts of additive manufacturing with DED Arc/M and attributing the dominant contributors to the carbon footprint. Collectively, the results indicate that a fully integrated experimental set-up together with standardised data structures and scalable analytics can couple monitoring, control, and sustainability, thereby realising the potential of digitalisation for high-quality and environmentally informed welding production. KW - Digitalisation KW - Arc welding KW - DED-arc KW - Life Cycle Assessment PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656812 DO - https://doi.org/10.1088/1757-899X/1342/1/012067 SN - 1757-8981 VL - 1342 IS - 1 SP - 1 EP - 15 PB - IOP Publishing AN - OPUS4-65681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinze, Christoph A1 - Schwenk, Christopher A1 - Rethmeier, Michael T1 - Numerical calculation of residual stress development of multi-pass gas metal arc welding N2 - In various applications, welding-induced residual stresses have a substantial impact on the integrity of welded constructions. Tensile residual stress can promote stress-corrosion cracking, brittle fracture, and reduces the fatigue life in service, as well as influences component design due to critical stress concentrations within the component. In the present paper, a six bead multi-pass gas metal arc weld of 20 mm thick structural steel S355J2+N is experimentally and numerically investigated. The studies include transient 2D and 3D numerical calculations which consider temperature-dependent material properties, phase transformations, 'thermal' tempering, transformation plasticity, volume change due to phase transformation, an elastic–plastic material model, and isotropic strain hardening. The experimentally determined and calculated residual stresses are in a good agreement. Furthermore, the influence of the preheat and interpass temperature on welding-induced residual stresses is shown in the present investigation. KW - Welding simulation KW - Gas metal arc welding KW - Welding-induced residual stress KW - Multi-pass welding KW - Sensitivity analysis PY - 2012 DO - https://doi.org/10.1016/j.jcsr.2011.08.011 SN - 0143-974x VL - 72 SP - 12 EP - 19 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-25629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinze, Christoph A1 - Schwenk, Christopher A1 - Rethmeier, Michael T1 - The effect of tack welding on numerically calculated welding-induced distortion N2 - A single-layer pulsed gas metal arc weld of structural steel S355J2+N with a thickness of 5 mm is experimentally and numerically investigated. Two tack welds are considered in the numerical simulation into two different ways. First, the tack welds are represented by elements belonging to the initial material. This implies that the 'tack weld material' was not exposed to any thermal load or phase transformation before actual welding was performed. The weld seam is shortened and there is an influence on the stiffness of the whole structure affecting the calculation result. Secondly, the tack welds were simulated as conducted in the experimental welding procedure. The cases considering tack welding are compared to a simulation neglecting tack welding and to the experimental results. The influence of tack welds on the calculated welding-induced distortion is clarified and a contribution to an improved simulation-based prediction of welding-induced distortion is possible by modeling tack welding according to the realistic fabrication procedure. KW - Welding simulation KW - Welding-induced distortion KW - Gas metal arc welding KW - Tack welding PY - 2012 DO - https://doi.org/10.1016/j.jmatprotec.2011.09.016 SN - 0924-0136 SN - 1873-4774 VL - 212 IS - 1 SP - 308 EP - 314 PB - Elsevier CY - Amsterdam AN - OPUS4-24820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Graf, Benjamin A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Laser metal deposition as repair technology for stainless steel and titanium alloys N2 - In a repair process chain, damaged areas or cracks can be removed by milling and subsequently be reconditioned with new material deposition. The use of laser metal deposition has been investigated for this purpose. The material has been deposited into different groove shapes, using both stainless steel and Ti-6Al-4 V. The influence of welding parameters on the microstructure and the heat affected zone has been studied. The parameters have been modified in order to achieve low heat input and consequently low distortion as well as low metallurgical impact. Finally, an evaluation of the opportunities for an automatized repair process is made. T2 - LANE 2012 - Laser Assisted net shape engineering 7 CY - Fürth, Germany DA - 12.11.2012 KW - Laser metal deposition KW - Laser powder cladding KW - Repair welding KW - Ti-6Al-4 V KW - Stainless steel PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-273066 DO - https://doi.org/10.1016/j.phpro.2012.10.051 N1 - Serientitel: Physics Procedia – Series title: Physics Procedia VL - 39 SP - 376 EP - 381 PB - Elsevier B.V. AN - OPUS4-27306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Gert A1 - Rethmeier, Michael ED - Kožuh, Z. T1 - Spot welding and weldbonding of high strength steels for lightweight auto body manufacturing N2 - The resistance spot welding procedure is one of the most important joining technique in lightweight car body shell mass production. Especially for newly developed ultra high strength steels (UHSS) and advanced high strength steels (AHSS), this joining technique has more advantages than other thermal and mechanical joining procedures for thin Steel sheets. Additionally, the technique of adhesive bonding and its combination with the technique of resistance spot welding called weldbonding becomes more and more important. The weldbonding affords many advantages, e.g. improved crash performance, fatigue behaviour and corrosion resistance. The main target of the contribution is to show the influence of different joined ultra and advanced high strength steels on the process reliability for both the resistance spot welding process and the weldbonding process. In this connection the influence of surface conditions of the steel sheets, the applied adhesive and the choice of the welding parameters on the process reliability will be studied. The results for the weldbonding procedure are based on different adhesives. Based on the representation of welding current ranges by weldability lobes, Statements concerning the weldbonding process reliability for some special AHSS and UHSS will be given. The mechanical behaviour of spot welded and weldbonded joints for different AHSS and UHSS will be studied. T2 - EUROJOIN 8 - 8th European Conference CY - Pula, Croatia DA - 24.05.2012 KW - Spot welding KW - Weldbonding KW - High strength steels KW - Process reliability KW - Mechanical properties of joints PY - 2012 SN - 978-953-7518-02-8 SP - 633 EP - 643 PB - Croatian Welding Society (CWS) CY - Zagreb AN - OPUS4-26383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gebhardt, Moritz Oliver A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael ED - Turichin, G. T1 - Laser-MSG-hybrid welding of thick walled precision pipes N2 - Thick-walled pipes made of steel are the basis of a large number of components in mechanical and installation engineering, e.g. for hydraulic components, in power station technology or in the petroleum industry. Particularly when strict positional and shape tolerances are demanded, the classical manufacturing process is chip-producing machining from the solid material. However, this is time-intensive and material-intensive. The laser/GMA hybrid processes with modern high-power lasers are a suitable alternative. With these processes, it is currently possible to weld components with a wall thickness up to approx. 15 mm with little distortion in one pass. However, in initial experiments, solidification cracks with longitudinal and vertical orientations in relation to the welding direction, so-called central line cracks, were established in welds on pipes. Within the framework of a research project, it was possible to determine the cause of the cracking and to find measures in order to avoid it. The technical boundary conditions could be complied with in this respect. The article gives an overview of the research project and the essential results. T2 - VII. International scientific and technical conference 'Beam technologies & laser application' CY - Saint-Petersburg, Russia DA - 18.09.2012 PY - 2013 SP - 235 EP - 247 PB - Publishing house SPbSPU AN - OPUS4-28041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Yang, Fan A1 - Rethmeier, Michael T1 - Porosity prediction in laser beam welding with a multimodal physics-informed machine learning framework N2 - Laser beam welding (LBW) of metallic components is a knowledge‑intensive manufacturing process whose quality depends on the complex multi‑physics. However, its engineering application is often hindered by the occurrence of porosity defects. Achieving a thorough understanding and reliable prediction of porosity defects remains difficult because it demands robust representation and reasoning over nonlinear and hard‑to‑observe physical information. In this study, we propose an integrated multimodal physics-informed machine learning (PIML) framework with the help of multi-physical modelling and experimental data to predict the porosity defects in laser beam welding of aluminum alloys. The whole framework contains a multimodal PIML model for predicting the porosity ratio and an ML-based estimator for relevant physical information. By utilizing the scalar welding parameters and high-dimensional physical information (probability of keyhole collapses, cumulative existing time of collapses, and molten pool geometry) as inputs, the multimodal PIML model shows great superiority in predicting the porosity ratio, with a reduction of the mean square error by 45%, compared with the ML model trained only with welding parameters. The ML-based estimator constructed with an encoder‐decoder architecture can accurately reproduce the critical physical information within a timeframe of seconds. By integrating these two ML models, the proposed framework advances engineering informatics by offering a scalable, physics-knowledge‑centric solution for fast and accurate porosity prediction in LBW manufacturing. KW - Laser beam welding KW - Porosity defect KW - Physics-informed machine learning KW - Multimodal model KW - Simulation PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657589 DO - https://doi.org/10.1016/j.aei.2026.104611 SN - 1474-0346 VL - 74 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-65758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -