Effect of Surface Plastic Deformation on the Structure and Mechanical Properties of the Working Layer of Bimetallic Tools.

A bimetallic joint obtained by surface plastic deformation (SPD) by surfacing a layer of tool steel R2M8 onto a billet from structural steel 30KhGSA by two different methods is studied. The structure and the microhardness of specimens of the bimetallic tool are determined. It is shown that SPD of the bimetal surfaced with cooling in the range of 350 – 200°C provides effective transformations in the steel components of the bimetal, of retained austenite into strain martensite, and produces a finer structure without cracks. As compared to the standard production technique (without SPD) the hardness of the surface tool steel R2M8 increases by 170 HV0.2 and that of the structural steel 30KhGSA increases by 200 HV0.2 in the heat-affected zone at a distance of 3.0 – 3.5 mm from the fusion boundary of the bimetal, which should raise the wear resistance of the tool. [ABSTRACT FROM AUTHOR]