Innovative Technology Investigation into Integrate the Surface Hardening Process with the Grinding Precision Finishing for CBN Grinding Crankshaft

The grinding hardening is a new surface heat treatment technology using grinding heat in which induce martensitic phase transformation in the surface layers of annealed or tempered steels to achieve surface strengthening processes and integrate the surface hardening process with the grinding precision machining. In the paper, A thermal model to describe this process has been presented from the thermal partition modeling and has been used to predict subsurface time- temperature profiles in the dry cylindrical grinding crankshaft using cubic boron nitride (CBN) wheels. The grinding hardening experiment was carried out in precision cylindrical grinder M1420E, using work-piece material 42CrMo4 and CBN grinding wheel under dry grinding condition. The experimental results showed the theoretical model is agreement with experimental results and the model can well forecast the grinding hardening depths.