Research on the possibility of controlling the properties of the structural steel surface hardening methods

Purpose. For cleaning small castings are widely used blast units machines periodic action. Working capacity these machines is mainly determined by the durability of working bodies that are experiencing Shock intensity abrasive wear. Needs some regime of surface hardening, as a result of which you can increase the wear resistance of the blades shot blasting machines and thereby reduce the expense for their manufacturing and replacement. Methodology. Proposed regime of surface hardening is carburizing and holding followed hardening from different temperatures. This surface treatment allows to obtain in the structure along with martensite and carbides large amount of residual austenite (Ares), that undergoes deformation martensite transformation in wear (DMPW) in the contact zone. Findings. It is shown that by changing the temperature of the hardening can be controlled phase composition, the number of metastable residual austenite and mechanical properties of carburized steel. Residual austenite in this case, is not reduced, as is commonly believed, but rather increases the abrasive wear resistance of carburized steel. It was found that to improve the wear resistance of steels surface treatment should be aimed at obtaining a surface layer of metastable austenitemartensite- carbide structure in which metastable residual austenite capable of DMPW. DMPW causes additional self-strengthening of surface layers of the working means and the formation of a particulate solid a martensite deformation compared with martensite hardening. Determined the optimal hardening regimes that improve wear resistance of parts 3-4 times. Originality. Developed new regimes of surface hardening low alloy steel. Practical value. Conducted production tests of the blades of steel shot blasting systems 20Mn, heat-treated using new regimes of hardening, showed that these details have a lifespan of up to 90-96 hours, which is 3-4 times the service life of the blades that are used in manufacturing without treatment