Microscopic Images and Microstructure of High-Speed Steel Surface after Gas-Laser Cutting

The results of experimental studies of the surface roughness and the microstructure of high-speed steel R6M5 after gas-laser cutting are presented. It is shown that the parameters the surface roughness obtained in the case of the studied samples correspond to typical values of the surface-roughness parameters after such types of machining as turning or grinding operations. In the course of gas-laser cutting, a quenching zone up to 110 μm in depth with an increased microhardness amounting to 10 600 ± 160 MPa is formed in the surface layer. Short-term tempering in the temperature range of Ac1–620°С does not lead to decomposition of the martensite; neither a transition zone nor tempering zone are revealed.