Thermal Fatigue Influence of Laser Treated Tool Steel Surface

This research project presents the investigation results of laser remelting and alloying especially the laser parameters and its influence on the structure and properties of the surface of the 32CrMoV12-28 and X38CrMoV5-3 hot work steels, using the high power diode laser (HPDL). As a result of the performed research structure changes were determined concerning the grain size and reinforcement ceramic particle distribution in the steel surface layer. The reason of this work was to determine the optimal laser treatment parameters, particularly the laser power applied to achieve good layer mechanical properties for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in hard working conditions. For alloying the tantalum carbide TaC, niobium carbide NbC as well as titanium carbide TiC powders were used. For investigations of the alloyed samples hardness and microhardness measurements of the different remelting areas were performed. The remelted layers which were formed in the surface of investigated hot work steel were examined metallographically and analyzed using light and scanning electron microscope as well as the investigations concerning ear resistance of the produced surface layer were carried out