Ensuring the quality indicators of the surface layer of parts made of 30KhGSA steel by laser microstructuring

The purpose of the work was to study the influence of laser microstructuring modes on the formation of qualitative indicators (the length of the laser exposure zone, microhardness) of the surface layer of parts made of hot-rolled sheet steel grade 30KhGSA. Methods . The structural medium-alloy steel of the 30KhGSA grade in the hot-rolled state (sheet 6 mm thick) was chosen as the object of research. Special samples were produced by laser cutting to study changes in the structure, structure and microhardness of the laser exposure zone. After laser cutting, one of the sides of the sample was subjected to mechanical milling in order to remove a layer with a modified structure of the material obtained during laser cutting. Next, laser microstructuring of the sample surfaces was performed using a continuous fiber laser. Metallographic and durometric studies were carried out to study the effect of laser microstructuring on changes in the structure and quality of the surface layer. Results . The peculiarities of changing the microstructure of the laser exposure zone depending on the type of laser treatment are considered. It is shown that, regardless of the type of laser treatment, a "white layer" is formed on the heat-strengthened surface, the thickness of which depends on the parameters of laser radiation: power, speed, spot diameter, focal length. It has been revealed that when milling operations are used as a preliminary mechanical treatment of the cutting edge surface, in the vast majority of cases a white layer is not formed. Conclusion . The results obtained can be used to create resource-saving material processing processes using highly concentrated energy flows.