Functional properties of laser modified surface of tool steel

Purpose: Investigations include alloying the surface of X40CrMoV5-1 hot-work tool steel with tungsten carbide using a high power diode laser (HPDL). Design/methodology/approach: The structural mechanism of surface layer development was determined and the effect of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer was studied. Findings: The fine grained martensite structure is responsible for hardness increase of the alloyed layer. The dependence is presented of micro-hardness change on the laser beam effect on the treated surface, and especially the hardness increase in the alloyed layer. The tribological wear relationships were determined for laser treated surface layers, determining friction coefficient, mass loss, and wear trace shape developed due to the abrasive wear of the investigated surfaces. The X40CrMoV5-1 conventionally heat treated steel was used as reference material. Practical implications: Laser surface modification has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones. Originality/value: The outcome of the research is an investigation showing the structural mechanisms accompanying laser alloying.