Increase of Durability of Austenitic Steel by Overlap of Carburization and Diffusion Saturation from Liquid Metal Medium Solutions Technologies

This paper investigated the overlap of carburization and diffusion saturation from liquid metal medium solutions technologies. The carburization of austhenic steel able to increase of its wear resistance and microhardness to 700HV. But this kind of treatment provided to reduction of corrosion resistance. This effect conditioned by formation of chromium carbides, herewith austenite of steel impoverished of chromium. This paper proposes the new technology lets increase the durability of asthenic steels, using carburization and diffusion saturation in eutectic Pb-Bi-Li medium with adding of nickel and chromium. The most effective technology consisted of previous carburization, diffusion saturation and final carburization. First carburization provided to increase of surface layers microhardness to 2800 MPa, diffusion saturation to 7500 MPa, the final carburization to 19500 MPa. The properties of coating depended of combination of technological impact and technological modes of every stage of technological process: temperature and duration. The temperature influenced to microhardness of coating: when the temperature increased microhardness decreased. The duration of diffusion saturation influenced to thickness of diffusion layer: when the duration increased the thickness increased too.