Effect of Laser Surface Melting on Structure and Properties of a High Speed Tool Steel

Abstract

The purpose of this research paper is focused on the high speed steel surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with carbides using high power diode laser HPDL. Investigation indicate the influence of the alloying carbides on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides and power implemented laser (HPDL). In the effect of laser alloying with powder of carbides occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved carbides and consolidation through enrichment of surface layer in alloying additions coming from dissolving carbides. Introduced particles of carbides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. The structural mechanism was determined of surface layers development, effect was studied 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, and especially on its hardness, abrasive wear resistance, and roughness. It 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.