TY - JOUR A1 - Lange, Fritz A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael A1 - Hilgenberg, Kai T1 - Numerical simulation of the weld pool dynamics during pulsed laser welding using adapted heat source models N2 - A transient simulation including the impact of the laser energy, the melting of the metal and the development of the weld pool was conducted to observe the evolution of the vapor capillary and the solidification of the melt in pulsed laser beam welding of AISI 304 steel. The phase field method was implemented to investigate the evolution and behavior of the liquid-gas interface during welding and to describe the condensed and vapor phases. The effects of phase transition, recoil pressure, thermo-capillary and natural convection, vaporization and temperature dependent material properties were taken into account. A Gaussian-like heat source under consideration of the Fresnel absorption model was used to model the energy input of the laser beam. The heat source model was extended by a newly developed empirical approach of describing multiple beam reflections in the keyhole. To validate this new model, the numerical results were compared to experimental data and good agreement regarding the size and shape of the weld pool was observed. T2 - LANE Conference 2018 CY - Fürth, Germany DA - 03.09.2018 KW - Pulsed laser beam welding KW - Weld pool dynamics KW - Multiple reflections KW - Vaporization PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458749 DO - https://doi.org/10.1016/j.procir.2018.08.044 SN - 2212-8271 VL - 74 SP - 679 EP - 682 PB - Elsevier Ltd. CY - Amsterdam [u.a.] AN - OPUS4-45874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Bakir, Nasim A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Weld pool shape observation in high power laser beam welding N2 - The geometry of the melt pool in laser beam welding plays a major role to understand the dynamics of the melt and its solidification behavior. In this study, a butt configuration of 15 mm thick structural steel and transparent quartz glass was used to observe the weld pool geometry by means of high-speed camera and an infrared camera recording. The observations show that the dimensions of the weld pool vary depending on the depth. The areas close to the weld pool surface take a teardrop-shape. A bulge-region and its temporal evolution were observed approximately in the middle of the depth of the weld pool. Additionally, a 3D transient thermal-fluid numerical simulation was performed to obtain the weld pool shape and to understand the formation mechanism of the observed bulging effect. The model takes into account the local temperature field, the effects of phase transition, thermo-capillary convection, natural convection and temperature-dependent material properties up to evaporation temperature. The numerical results showed good accordance and were furthermore used to improve the understanding of the experimentally observed bulging effect. T2 - LANE Conference 2018 CY - Fürth, Germany DA - 03.09.2018 KW - High power laser beam welding KW - Weld pool shape KW - Bulging KW - Numerical process simulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458759 DO - https://doi.org/10.1016/j.procir.2018.08.043 SN - 2212-8271 VL - 74 SP - 683 EP - 686 PB - Elsevier Ltd. CY - Amsterdam [u.a.] AN - OPUS4-45875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Xiangmeng A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Numerical study of additional element transport in wire feed laser beam welding N2 - The transport phenomena in the wire feed laser beam welding are investigated numerically. A three-dimensional transient heat transfer and fluid flow model coupled with free surface tracing and element transport is developed. A ray-tracing method with local grid refinement algorithm is used to calculate the multiple reflections and Fresnel absorption on the keyhole wall. The filler material flows backward along the lateral side of the weld pool, and subsequently flows forward along the longitudinal plane. The occurrence of the bulging phenomenon may further prevent the downward transfer of the additional elements to the root of the weld pool. KW - Laser beam welding KW - Element transport KW - Filler wire KW - Numerical modelling PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513271 DO - https://doi.org/10.1016/j.procir.2020.09.129 VL - 94 SP - 722 EP - 725 PB - Elsevier B.V. AN - OPUS4-51327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Numerical analysis of the partial penetration high power laser beam welding of thick sheets at high process speeds N2 - The present work is devoted to the numerical analysis of the high-power laser beam welding of thick sheets at different welding speeds. A three-dimensional transient multi-physics numerical model is developed, allowing for the prediction of the keyhole geometry and the final penetration depth. Two ray tracing algorithms are implemented and compared, namely a standard ray tracing approach and an approach using a virtual mesh refinement for a more accurate calculation of the reflection points. Both algorithms are found to provide sufficient accuracy for the prediction of the keyhole depth during laser beam welding with process speeds of up to 1.5 m/min. However, with the standard algorithm, the penetration depth is underestimated by the model for a process speed of 2.5 m/min due to a trapping effect of the laser energy in the top region. In contrast, the virtually refined ray tracing approach results in high accuracy results for process speeds of both 1.5 m/min and 2.5 m/min. A detailed study on the trapping effect is provided, accompanied by a benchmark including a predefined keyhole geometry with typical characteristics for the high-power laser beam welding of thick plates at high process speed, such as deep keyhole, inclined front keyhole wall, and a hump. KW - High-power laser beam welding KW - High process speeds KW - Deep penetration KW - Numerical modeling KW - Ray tracing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532170 DO - https://doi.org/10.3390/met11081319 SN - 2075-4701 VL - 11 IS - 8 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-53217 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Meng, Xiangmeng A1 - Bakir, Nasim A1 - Üstündag, Ömer A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - The bulging effect and its relevance in high power laser beam welding N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and an infrared camera is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs more frequently during partial penetration above 6 mm and complete penetration above 8 mm penetration depth, respectively. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root. T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP) KW - High-power laser beam welding KW - Bulge effect KW - Solidification cracking KW - Multi-physical modelling KW - Metal mixing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539149 DO - https://doi.org/10.1088/1757-899X/1135/1/012003 VL - 1135 IS - 012003 SP - 1 EP - 11 PB - IOP Publishing AN - OPUS4-53914 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Karkhin, V. A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - A General Analytical Solution for Two-Dimensional Columnar Crystal Growth during Laser Beam Welding of Thin Steel Sheets N2 - A technique for calculating the main solidification parameters for a two-dimensional columnar crystal growth during complete penetration laser beam welding of thin steel sheets was developed. Given that the weld pool interface is described by Lamé curves (superellipses) within the horizontal plane of growth, general analytical solutions were derived for the geometry of the crystal axis and the corresponding growth rate and cross-sectional area of the crystal. A dimensionless analysis was performed to provide insights on the dependence of the solidification parameters on the shape and dimensions of the rear part of the weld pool boundary. The derived solutions were applied for the case of complete penetration laser beam keyhole welding of 2 mm thick 316L austenitic chromium-nickel steel sheets. It was shown that the reconstruction of the weld pool boundary with Lamé curves provides higher accuracy and flexibility compared to results obtained with elliptical functions. The validity of the proposed technique and the derived analytical solutions was backed up by a comparison of the obtained solutions to known analytical solutions and experimentally determined shapes and sizes of the crystals on the top surface of the sheet. The dimensions of the calculated crystal axis correlated well with the experimentally obtained results. KW - General analytical solutions KW - Two-dimensional solidification KW - Columnar crystal growth KW - Lamé curves KW - Laser beam welding PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576788 DO - https://doi.org/10.3390/app13106249 IS - 10 SP - 1 EP - 10 ET - 13 AN - OPUS4-57678 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 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562429 DO - https://doi.org/10.2351/7.0000739 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 - Yang, Fan A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Experimental and numerical investigations of suppression mechanisms by an oscillating magnetic field on process porosity during laser beam welding N2 - The magnetohydrodynamic (MHD) technology is recognized as a promising approach for improving the quality of deep penetration laser beam welding. This study employs experimental and numerical methods to investigate the effects of an auxiliary oscillating magnetic field on reducing porosity in the laser beam welding of 5754 aluminum alloy. The experimental results clearly demonstrate a significant reduction of 97% in the porosity ratio of the welded joints applied with an oscillating magnetic field compared to those without magnetic field, thereby validating the efficiency of applying MHD technology in mitigating porosity during the laser beam welding process. In addition, a transient 3D multi-physical model has been developed, integrating the MHD model and metal vapor plume, to gain a more comprehensive understanding of the porosity suppression mechanism. The weld pool shape is significantly widened and enlarged because of the Lorentz force, which facilitates the escape of gas bubbles. Meanwhile, the introduction of an oscillating magnetic field generates a time-averaged downward Lorentz force. This averaged downward Lorentz force, in turn, enhances and stables the downward fluid flow, which hinders the bubble backward movement. Meanwhile, this averaged downward Lorentz force induces an upward electromagnetic expulsive force on the bubble, which effectively increases the upward escape velocity of bubbles in the weld pool. The simulation results agree well with the experimental results. T2 - 44. Assistentenseminar Füge- und Schweißtechnik CY - Päwesin, Germany DA - 20.09.2023 KW - Laser beam welding KW - Numerical simulation KW - Magnetohydrodynamic technology KW - Porosity defect KW - Keyhole PY - 2024 UR - https://www.dvs-media.eu/de/neuerscheinungen/4671/44.-assistentenseminar-fuegetechnik SN - 978-3-96144-267-6 VL - 394 SP - 77 EP - 86 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-60784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Rethmeier, Michael T1 - Challenges in dynamic heat source modeling in high-power laser beam welding N2 - The amount of absorbed energy in the keyhole as well as its spatial and temporal distribution is essential to model the laser beam welding process. The recoil pressure, which develops because of the evaporation process induced by the absorbed laser energy at the keyhole wall, is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the effect of laser radiation on the weld metal is crucial to obtain reliable and accurate simulation results. In this paper, we discuss manyfold different improvements on the laser-material interaction, namely, the ray tracing method, in the numerical simulation of the laser beam welding process. The first improvement relates to locating the exact reflection points in the ray tracing method using a so-called cosine condition in the determination algorithm for the intersection of reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2, thus ignoring around 14% of the total laser beam energy. In the third step, the changes in the laser radiation distribution in the vertical direction were adapted by using different approximations for the converging and the diverging regions of the laser beam, thus mimicking the beam caustic. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements. KW - Laser beam welding KW - Laser energy distribution KW - Ray tracing KW - Numerical modeling PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584748 DO - https://doi.org/10.2351/7.0001079 VL - 35 IS - 4 SP - 1 EP - 9 PB - Laser Institute of America AN - OPUS4-58474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yang, Fan A1 - Meng, Xiangmeng A1 - Putra, Stephen Nugraha A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Numerical analysis of the effect of an oscillating metal vapor plume on the keyhole and molten pool behavior during deep penetration laser beam welding N2 - The effect of the oscillating metal vapor plume on the keyhole and molten pool behavior during the laser beam welding of AlMg3 aluminum alloys is investigated by experimental and numerical methods. The real-time height of the metal vapor plume is measured by high-speed camera observation. The obtained experimental results are used to evaluate the additional heating source and laser beam attenuation caused by the scattering and absorption based on the Beer–Lambert theory. Furthermore, the dynamic behavior of the metal vapor plume is incorporated into a 3D transient heat transfer and fluid flow model, coupled with the ray tracing method, for the laser beam welding of the AlMg3 alloy. It is found that additional heating resulting from the scattered and absorbed laser beam energy by the metal vapor plume significantly expands the shape of the molten pool on the top region. Moreover, the oscillating metal vapor plume caused the fluctuation of the high-temperature region in the molten pool. The probability of keyhole collapse at the bottom increases 17% due to the oscillating laser power induced by the laser beam attenuation. The internal interplay between the metal vapor plume, molten pool shape, and keyhole collapse is obtained. The developed model has been validated by experiments, which shows a good agreement. T2 - International Congress of Applications of Lasers & Electro-Optics 2023 CY - Chicago, IL, USA DA - 16.10.2023 KW - Deep penetration laser beam welding KW - Numerical simulation KW - Oscillating vapor plume KW - Keyhole collapse PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587978 DO - https://doi.org/10.2351/7.0001094 SN - 1938-1387 SN - 1042-346X VL - 35 IS - 4 SP - 1 EP - 10 PB - AIP Publishing CY - Melville, NY AN - OPUS4-58797 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 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 Al alloy N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase in the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are analyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain size after welding verify the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains, that have been solidified and formed previously, from further growth and generates some small cellular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement. KW - Laser beam welding KW - Magnetic field KW - Crystal branch development KW - Grain refinement KW - Periodic solidification pattern PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584905 DO - https://doi.org/10.2351/7.0001085 SN - 1042-346X VL - 35 IS - 4 SP - 1 EP - 10 PB - AIP Publishing AN - OPUS4-58490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Bachmann, Marcel T1 - Numerische Modellierung einer elektromagnetischen Schmelzbadkontrolle beim Laserstrahlschweißen von nicht-ferromagnetischen Werkstoffen N2 - Die Verfügbarkeit von Laserstrahlquellen mit immer höheren Leistungsparametern ermöglicht ein effektives und schnelles Schweißen von stetig größer werdenden Blechdicken. Dabei treten Herausforderungen bezüglich der Prozessstabilität, z.B. ein Austropfen von Schmelze bei Durchschweißungen sowie die Beherrschung der Dynamik, insbesondere an den freien Oberflächen, die stark von Oberflächenspannungseffekten beeinflusst wird, in den Vordergrund. Die vorliegende Arbeit liefert einen primär numerischen Beitrag zur Anwendung oszillierender sowie zeitlich invarianter magnetischer Felder beim Hochleistungs-Laserstrahlschweißen von nicht-magnetischen Bauteilen hoher Blechdicke. Für die simulativen Untersuchungen wurden die Materialien Aluminium sowie austenitischer Stahl AISI 304 herangezogen und mit Querschliffen von exemplarisch durchgeführten Schweißungen an der Legierung AlMg3 bzw. AISI 304 verglichen. Die Simulationen wurden mit dem kommerziellen Finite- Elemente-Paket COMSOL Multiphysics durchgeführt. In diesem Rahmen wurden Strömungs- und Temperaturfelder sowie die Verteilungen der elektromagnetischen Feldgrößen berechnet. Die Bewertung der elektromagnetischen Beeinflussung des Schmelzbades erfolgte für die Anwendung oszillierender Magnetfelder zur Vermeidung des Schmelzaustropfens anhand der Druckverteilungen an unterer und oberer Schmelzbadoberflächen. Der Grad der Strömungsdämpfung durch elektromagnetische Kräfte wurde durch dimensionslose Kennzahlen unter Berücksichtigung des turbulenten Strömungszustandes bewertet. Es konnte im Rahmen der Arbeit gezeigt werden, dass durch den im Schmelzbad wirkenden vertikalen Anteil der Lorentzkraft, basierend auf einem oszillierenden magnetischen Feld unterhalb der Schweißzone und den im Werkstück induzierten elektrischen Wirbelströmen, ein Austropfen von verflüssigtem Material verhindert und somit ein sicherer Schweißprozess ermöglicht werden kann. Die hierfür benötigten elektromagnetischen Leistungen liegen für 20 mm dickes Aluminium und seinen Legierungen im Bereich mehrerer hundert Watt. Numerische Untersuchungen zur Strömungsdämpfung mittels permanentmagnetischer Felder zeigen die Möglichkeit auf, die Strömungsgeschwindigkeit und die lokale Turbulenzverteilung effektiv zu reduzieren. Dabei spielt die Polarität des quer zur Strömungsrichtung angelegten magnetischen Feldes keine Rolle für die resultierenden Kräfte. Die rechnerisch ermittelte Veränderung der Nahtform hin zu einem V-förmigen Profil konnte experimentell bestätigt werden. Die dazu notwendigen magnetischen Flussdichten für den Laborversuch liegen im Bereich kommerziell erhältlicher Neodym- Eisen-Bor Magnete bei etwa 500 mT. N2 - The availability of high power laser beam sources enables an effective and fast welding process of ever thicker metal parts. At the same time, challenges concerning the process stability appear, e.g. a drop-out of molten material in full-penetration welding as well as the control of the dynamics, especially in the vicinity of the free surfaces of the weld bead where surface tension effects dominate. The present work provides a primary numerical contribution to the application of oscillating as well as time-invariant magnetic fields to the high power laser beam welding of non-ferromagnetic metal parts of high thickness. For the simulations, the materials under investigation were aluminum and austenitic stainless steel AISI 304. The numerical results were compared to macrographs of exemplary test welds of the alloys AlMg3 and AISI 304. The simulations were conducted with the commercial finite element package COMSOL Multiphysics. In the framework of the investigations, calculations were done for the fluid flow and temperature as well as for the electromagnetic field quantities. The evaluation of the electromagnetic weld pool control for the application of oscillating magnetic fields to avoid liquid metal drop-out was carried out on the basis of pressure distribution analysis between the lower and upper weld pool surfaces. The degree of magnetic damping by Lorentz forces was calculated by dimensionless numbers also accounting for the turbulent state of the fluid flow. In this work, it could be shown, that the vertical part of the Lorentz forces, that are based on an oscillating magnetic field below the process zone and its induced eddy currents in the workpiece, prevents the liquid metal from drop-out. Thereby, a reliable welding process was made possible. The electromagnetic power used for the welding of a 20 mm thick aluminum alloy with electromagnetic support lies in the range of several hundreds Watt. Numerical investigations concerning the flow damping by permanent magnetic fields show the possibility to reduce the local flow velocity as well as the turbulence distribution effectively. The polarity of the applied magnetic field, which is aligned in horizontal direction and vertical to the welding direction, is indecisive for the direction of the developing Lorentz forces. The numerically predicted transition of the cross-sectional weld bead geometry to a V-shaped profile could also be proved experimentally. The required magnetic flux density for that was in the range of commercially available neodymium iron boron magnets of around 500 mT. T3 - BAM Dissertationsreihe - 113 KW - Schmelzbadstütze KW - Laserstrahlschweißen KW - Marangoni-Effekt KW - Hartmann-Effekt KW - numerische Simulation PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459 SN - 978-3-9815944-9-2 SN - 1613-4249 VL - 113 SP - 1 EP - 189 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-45 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -