Currently, most of the researches studying grind-hardening have used Design of Experiments approach to obtain empirical correlations Without any in-depth theoretical analyzes. In this paper, a comprehensive numerical model is developed to simulate the temporal and spatial temperature distributions of the workpiece under the dry grind-hardening condition using finite element method. The simulated hardness penetration depth is deduced from the local temperature distribution and time history of workpiece and its martensitic phase transformation conditions. The results from simulations are validated with experiments. The effect of two major grinding parameters, workpiece speed and depth of cut, on the hardness penetration depth are discussed. (C) 2008 Published by Elsevier Ltd.