TY - CONF A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael ED - Sommitsch, C. ED - Enzinger, N. T1 - Multi-physical finite element simulation of an electromagnetic weld pool support in full-penetration high power laser beam welding of metal plates T2 - 10th International seminar numerical analysis of weldability CY - Leibnitz, Austria DA - 2012-09-24 KW - Laser beam welding KW - Electromagnetic weld pool support KW - Marangoni convection PY - 2013 SN - 978-3-85125-293-4 VL - 10 SP - 5 EP - 20 PB - Verlag der Technischen Universität Graz AN - OPUS4-29982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Numerical simulation of electromagnetic melt control systems in high power laser beam welding N2 - The availability of laser sources with a power of 20 kW upwards prepared the ground for laser beam welding of up to 20 mm thick metal parts. Challenges are the prevention of gravity-driven melt drop-out and the control of the dynamics mainly due to the Marangoni flow. Coupled numerical turbulent fluid flow, thermal and electromagnetic simulations and experimental validation with aluminum AlMg3 and stainless steel AISI 304 were done for alternating and steady magnetic fields perpendicular to the process direction. The first can prevent melt sagging in full-penetration welding by Lorentz forces in the melt induced by an AC magnet located below the weld specimen counteracting gravitational forces. The latter controls the Marangoni flow by Lorentz braking forces in the melt by the so-called Hartmann effect. The simulations show that the drop-out of aluminum and stainless steel can be avoided for 20 mm thick fullpenetration welds with moderate magnetic flux densities of 70 mT and 95 mT at oscillation frequencies of 450 Hz and 3 kHz, respectively. The experiments are in good agreement but show somewhat larger values for steel, whose weakly ferromagnetic properties are a possible reason. The investigations with steady magnetic fields reveal the possibility to mitigate the dynamics significantly beginning with around 500 mT at laser penetration depths of approximately 20 mm. T2 - ICALEO 2013 - 32nd International congress on applications of lasers & electro-optics CY - Miami, FL, USA DA - 2013-10-06 KW - Laser beam welding KW - Electromagnetic weld pool support KW - Hartmann effect PY - 2013 SN - 978-0-912035-98-7 IS - Paper 401 SP - 50 EP - 59 AN - OPUS4-29466 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 - Magnets improve quality of high-power laser beam welding KW - Laser beam welding KW - Hartmann effect KW - Marangoni flow PY - 2013 UR - http://weldingdesign.com/processes/magnets-improve-quality-high-power-laser-beam-welding SN - 0043-2253 SP - 1 EP - 3(?) PB - Penton/IPC CY - Cleveland, Ohio AN - OPUS4-29412 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 - CONF A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - CFD simulation of the liquid metal flow in high power laser welding of aluminium with electromagnetic weld pool support T2 - 2nd International conference on fluid mechanics and heat and mass transfer 2011 CY - Corfu, Greece DA - 2011-07-14 KW - Electromagnetic weld pool support KW - Laser beam welding KW - Lorentz force KW - Marangoni stresses KW - Natural convection PY - 2011 SN - 978-1-61804-020-6 SP - 179 EP - 184 PB - WSEAS Press AN - OPUS4-24171 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 - Magnets improve quality of high-power laser beam welding N2 - Welding is one of the most critical operations for the construction of reliable metal structures in everything from ships to reactor vessels. When welds fail, the entire structure often fails—so expectations on weld quality have never been higher. Any process that uses a localized heat source, such as welding, is likely to result in some distortion. The welding process of very thick metal components is not inherently stable and is barely controllable without external forces. KW - Laser beam welding KW - Hartmann effect KW - Electromagnetic weld control KW - Finite element simulation PY - 2015 UR - http://digital.industrial-lasers.com/industriallasers/20150304#pg1 SN - 1523-4266 SN - 0888-935X VL - 30/2 IS - March/April SP - 10 EP - 12 PB - Pennwell CY - Tulsa, Okla., USA AN - OPUS4-33037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Avilov, Vjaceslav A1 - Fritzsche, André A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Full penetration laser beam welding of thick duplex steel plates with electromagnetic weld pool support N2 - Full penetration high power bead-on-plate laser beam welding tests of up to 20 mm thick 2205 duplex steel plates were performed in PA position. A contactless inductive electromagnetic (EM) weld pool support system was used to prevent gravity drop-out of the melt. Welding experiments with 15 mm thick plates were carried out using IPG fiber laser YLR 20000 and Yb:YAG thin disk laser TruDisk 16002. The laser power needed to achieve a full penetration was found to be 10.9 and 8.56 kW for welding velocity of 1.0 and 0.5 m min−1, respectively. Reference welds without weld pool support demonstrate excessive root sag. The optimal value of the alternating current(AC) power needed to completely compensate the sagging on the root side was found to be ≈1.6 kW for both values of the welding velocity. The same EM weld pool support system was used in welding tests with 20 mm thick plates. The laser beam power (TRUMPF Yb:YAG thin disk laser TruDisk 16002) needed to reach a full penetration for 0.5 m min−1 was found to be 13.9 kW. Full penetration welding without EM weld pool support is not possible—the surface tension cannot stop the gravity drop-out of the melt. The AC power needed to completely compensate the gravity was found to be 2 kW. KW - Electromagnetic weld pool control KW - Duplex stainless steel KW - Laser beam welding KW - Full penetration welding PY - 2016 DO - https://doi.org/10.2351/1.4944103 SN - 1042-346X SN - 1938-1387 VL - 28 IS - 2 SP - 022420-1 EP - 022420-7 PB - American institute of physics CY - Woodbury, NY, USA AN - OPUS4-35668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avilov, Vjaceslav A1 - Fritzsche, André A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Full penetration laser beam welding of thick duplex steel plates with electromagnetic weld pool support N2 - Full penetration high power bead-on-plate laser beam welding tests of up to 20 mm thick 2205 duplex steel plates were performed in PA position. A contactless inductive electromagnetic (EM) weld pool support system was used to prevent gravity drop-out of the melt. Welding experiments with 15 mm thick plates were carried out using IPG fiber laser YLR 20000 and Yb:YAG thin disk laser TruDisk 16002. The laser power needed to achieve a full penetration was found to be 10.9 and 8.56kW for welding velocity of 1.0 and 0.5 m min(-1), respectively. Reference welds without weld pool support demonstrate excessive root sag. The optimal value of the alternating current (AC) power needed to completely compensate the sagging on the root side was found to be approximate to 1.6 kW for both values of the welding velocity. The same EM weld pool support system was used in welding tests with 20 mm thick plates. The laser beam power (TRUMPF Yb:YAG thin disk laser TruDisk 16002) needed to reach a full penetration for 0.5 m min(-1) was found to be 13.9 kW. Full penetration welding without EM weld pool support is not possible-the surface tension cannot stop the gravity drop-out of the melt. The AC power needed to completely compensate the gravity was found to be 2 kW. (C) 2016 Laser Institute of America T2 - ICALEO 2015 - 34th International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 2015-10-18 KW - Electromagnetic weld pool support KW - Laser beam welding KW - Duplex stainless steel PY - 2015 SN - 978-1-940168-05-0 SP - 571 EP - 579 PB - Amer inst physics CY - Melville, NY, USA AN - OPUS4-35035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -