Effect of Laser Beam Alloying Strategies on the Metallurgical and Mechanical Properties of Hot Forming Tool Steels

Publication date: 2016 Source:Physics Procedia, Volume 83 Author(s): Konstantin Hofmann, Franziska Neubauer, Matthias Holzer, Vincent Mann, Florian Hugger, Stephan Roth, Michael Schmidt In terms of increasing lightweight designs of car body parts, the machining of high strength steels in hot stamping processes becomes of particular interest. Due to high process forces at hot stamping, the surface of such tools in the area of maximal stress is subject wear, which necessitate some local increase of microhardness to enhance the mechanical performance. Especially laser beam alloying using filler wire and beam oscillation is some suitable method to modify the mechanical properties of tool surfaces to emcompass some continuous martensitic structure, featuring a certain microhardness. Nevertheless the thermal energy input during laser beam alloying induces tempering in the heat affected zone and reduces the hardness. This paper discusses the influence of alloying strategies on the thermal energy input and the resulting metallurgical structure of modified tool surfaces. Also the cooling behavior of alloyed lines for different energy inputs per unit length is of interest. Therefore, the metallurgical microstructure is analyzed regarding microhardness as well as formation of carbides. Furthermore, a numerical thermal simulation is developed to investigate the temperature profile in the heat affected zone of the specimen. These investigations permit the control of the spatiotem...

Source: Physics Procedia - September 17, 2016 Category: Physics Source Type: research