DefinePK

Abstract

This article discusses the issues of increasing the reliability of loaded machine parts by modifying the surface using laser heating. In order to increase the durability of vehicle differential axle a method of surface modification has been considered, which combines advantages of discrete alloying of steel surface upon laser heating, diffusion metallization, and nitriding. Combined technology of surface strengthening of engineering steels is proposed, which is comprised of laser alloying with chromium, subsequent diffusion metallization and nitriding in environment of dissociated ammonia. It is demonstrated that preliminary local alloying makes it possible to decrease processing temperature and to obtain diffusion layer thickness in two times higher in comparison with conventional procedures. Nitriding of surface alloyed steel 40Kh (0, 4%C, 1%Cr) increases microhardness of strengthened layer up to 17.5 GPa, promotes formation of transient layer which positively influences on wear resistance of parts, increases their durability.