Characteristics of structural phase transformations in high-alloy steels subjected to laser heat treatment

An experimental investigation was made of pulsed laser heat treatment of annealed tungsten and tungsten–molybdenum–cobalt high-speed cutting steels. The results indicated that saturated austenite did not form during thermal cycles of duration typical of free-running solid-state lasers. The observed increase in microhardness of the surface layer was due to the high density of dislocations formed by laser heating. A model of an α→γ transition in this class of steels subjected to pulsed laser heating was proposed and analyzed theoretically. The model allowed for the kinetics of the austenitic transformation and microplastic deformation.