The dissipated heat in grinding is utilized to induce martensitic phase transformation and strengthen the unhardened steel in grinding, which can be integrated into existing production lines. The orthogonal experiments were performed to analyze the main impacting factors and the rule between the parameters and hardness layer results. The surface hardness depth is varied with different surface zone. Cutting depth is the main factor of impacting the surface hardness and hardness layer depth. Hardness layer depth is higher with the cutting depth deeper and smaller with Table speed faster, but the surface hardness is higher with the Table speed faster.