Features of the structure of the surface layer of 07Kh16N6 steel in grinding

Under action on the surface of the material a significant change in the structure of its surface layer is possible (deformation transformation of unstable austenite into martensite). Such a phase (γ → α) transformation may also occur in the absence of external force action as the result of redistribution of surface stresses in electropolishing of specimens. In this work a study was made of the influence of surface mechanical action on the surface layer structure of 07Kh16N6 steel specimens after different stages of preparation of metallographic specimens. In this case in heavy grinding local high-temperature heating occurs. The austenite formed acquires stability and is retained as the result of rapid cooling of the steel by heat flow into the body of the specimen. As a result an austenitic structure is formed in the surface layer with a preferentially martensitic structure in the body. With a change in grinding to paper with a finer grain size the quantity of austenite in the layer decreases and it is equalized to the original volumetric condition.