Abstract:The grind-hardening process uses the heat generated within the grinding zone in order to produce surface hardening of the workpiece combined with mechanical compound function. A three dimensional (3D) analytical model to predict grinding temperature is given, the thermo -metallurgical effects are analysed and the hardness of workpiece after grinding hardening is predicted. Based on the transient temperature distribution and the differential equation of nonsteady -state three -dimensional (3D) heat conduction, where the interdependence among the grinding wheel, the workpiece and the coolant were described, also the thermal diffusivity in material was considered. A 3D analytical model to predict grinding temperature was given. Combining the calculation for the proportion of the austenite phase and the analysis for thermo -metallurgical effects in transition of perlite in engineering process, residue austenite and martensite, the hardening depth of workpiece machined was predicted. The predication was realized for distribution of hardening depth along with changing of machining parameters. All these of the model are well coincided with the finite element model (FEM) and the experimental measurement results.