Formation and control of grinding-hardened layer

On the basis of the surface grinding-hardening test, the microstructures and property of the grinding-hardened layer depth of 40Cr steel were studied. The results show that under the coupling actions of the thermal and mechanics during the grinding hardening process, there are no remarkable effects of the grinding conditions upon the microstructure and microhardness value in high-hardness area of the hardened layer, and the completely hardening zone whose microhardness is between 630HV_0.5 and 680HV_0.5 is of lathe martensites and a few twinborn martensites. As the depth of cut increasing, or table speed decreasing, and the grinding wheel with fine grain size and high hardness is adopted at the some time, the depth of hardened layer and the maximal compressive residual stress and its influencing depth of hardened layer would increased, thus longer service life of grinding-hardening parts can be obtained.