TY - CONF A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Transient Process Simulation of Heat Transfer in Laser Beam Welding with an Equivalent Heat Source T2 - COMSOL Conference 2017 (Proceedings) N2 - This paper presents a multiphysics modelling framework developed for the prediction of the three-dimensional transient temperature field of the laser welding process. The numerical model consists of two studies. In the first study, a steady-state CFD process simulation of full-penetration keyhole laser beam welding was performed. Considering the effects of, thermo-capillary and natural convection, latent heat of fusion and temperature-dependent material properties up to evaporation temperature the local weld pool geometry and temperature field were obtained. These results were used in the second subsequent study as an equivalent volumetric heat source by the prediction of the transient thermal cycle during and after fusion welding. Here the energy input and the movement of the heat source were realized by a novel technique, making use of pointwise constraints and a moving mesh provided with helper lines and additional remeshing condition. The numerically calculated results were compared to experimentally observed weld pool shapes and time-temperature curves showing a very good agreement. T2 - COMSOL Conference 2017 CY - Rotterdam, Netherlands DA - 18.10.2017 KW - High power laser beam welding KW - Transient heat transfer KW - Equivalent volumetric heat source KW - Moving mesh KW - Pointwise constraints PY - 2017 SP - 1 EP - 7 CY - Rotterdam AN - OPUS4-42701 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Spranger, Felix A1 - Bachmann, Marcel T1 - Localized laser dispersing of titanium-di-boride with pulsed fiber laser T2 - ICALEO 2017 - International congress on applications of lasers & electro-optics (Proceedings) N2 - In this paper, titanium-di-boride is dispersed on a cold-working tool steel by use of a pulsed fiber laser with high beam quality to produce separated and elevated surface features. The potential to adjust the geometry as well as the mechanical properties of the produced structures in dependence on the process parameters (pulse power, pulse duration) is described by means of metallographic and topographical investigations. It can be ascertained that very hard (hardness > 1000 HV1) surface features of different shape (spots and short lines) can be produced. They are characterized by a fine-grained microstructure resulting from a rapid solidification and finely dispersed TiB2 particles. Finally, the paper proposes different applications for this structuring technique. T2 - ICALEO 2017 - International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 22.10.2017 KW - Laser dispersing KW - Titanium-di-boride KW - Surface structuring KW - Laser implantation PY - 2017 SN - 978-1-940168-1-42 SP - Paper 118, 1 EP - 9 AN - OPUS4-42868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -