The study of properties of laser modified hot-work tool steel surface layer

Purpose: The following paper is a synopsis of the fundamentals of laser remelting and alloying, outlining some of its benefits compared with conventional heat treatment techniques of hot-work tool steel X40CrMoV5-1. Design/methodology/approach: A selective review of the experimental research carried out in this area is presented. The aim of such treatment was to harden and alloy the steel surface which had been previously coated with the paste consisting of the tungsten carbide and the inorganic binder. Findings: Development of the surface layer was observed in which one can distinguish the remelted zone, heat-affected zone and the transient zone. Occurrences of the un-melted tungsten carbide grains were observed in the structure and the increased tungsten content compared to the native material, whose variable concentration is connected with the molten metal fluctuation in the pool during alloying. The fine grained, dendritic structure occurs in the remelted and alloyed zone with the crystallization direction connected with the dynamical heat abstraction from the laser beam influence zone. Practical implications: 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. Originality/value: The outcome of the research is an investigation showing the structural mechanisms accompanying laser alloying.