Hardening of 30KhGS Steel Gearwheels during Laser Cutting

The microstructure and microhardness of the surface layer of the gearwheels produced by laser cutting of 6-mm-thick 30KhGS sheet steel disks at a laser power of 1200 W and a cutting speed of 20 mm/s are studied. The structure of the heat-affected zone is found to have the following structure: a 6-μm-thick white layer forms on the cutting surface; under it, a structure consisting of martensite and a small amount of retained austenite forms at the side facing a gas jet; at the side facing laser radiation, the structure consists of a sorbite–troostite mixture with spheroidized carbide inclusions. Below, the structure is represented by a sorbite–troostite mixture and martensite grains. The modified layer thickness is 100–250 μm, and the hardness of the layer can reach 500–716 HV.