Prediction of hypo eutectoid steel softening due to tempering phenomena in laser surface hardening.

The paper presents a mathematical model for the predicting of the material mechanical properties variation, in laser hardening of hypo eutectoid steel, when the softening effects due to the overlapping trajectories are considered. That generally occurs during laser hardening of industrial parts, especially when wide areas have to be treated, due to the tempering phenomena. In this paper an original tempering model for the prediction of the hardness reduction is presented. The proposed model is integrated in a Laser Hardening simulation package, previously developed by the Authors. Experimental activities are also presented to validate the model.