Structure and Microhardness of Steel R6M5 Coating after Spraying and Subsequent Friction Treatment

The process of frictional processing of a plasma coating made of R6M5 steel on a cylindrical substrate has been developed and studied. Friction processing was carried out for 10–70 s by cyclic application of pressure of 30 MPa of two tools made of R18M5 steel on a coating rotating at a speed of 900 rpm, including additional movement of tools along the generatrix of the cylindrical substrate. With an increase in the friction treatment time, the coating surface temperature rises to 1202°C, which is sufficient for plastic deformation of the coating material. The coating microhardness after plasma spraying is 3.13 GPa; after friction treatment, it increases to 7.64 GPa. The large degree of deformation of the upper layers of coating under the action of tools determines the increase in the microhardness of the coating from the substrate to the free surface from 5.85 to 7.64 GPa.