Mathematical modeling of heat transfer in laser surface hardening of AISI 1050 steel

Laser surface hardening is a method used for surface modification without affecting the bulk properties of materials. Due to rapid cooling and little thermal penetration in the surface layer, a homogenous structure and little distortion are usually obtained. When a high power laser irradiates a material surface, a part of the laser energy is absorbed and conducted into the interior of the material. If the absorbed energy is high enough, the material surface will melt and even vaporizes. Consequently the temperature of the process is of promote importance to incorporate an appropriate structural layer. In this regard, a study has been carried out to implement a mathematical modeling method to control the temperature gradient, which affects on the depth of the hardened layer. The model is based on solving the heat transfer equation and such a condition by assuming that the thermo-physical properties of the material are independent of the temperature. To evaluate the application of the proposed model, laser surface hardening was carried out to AISI 1050 steel, using a 1 kW CO₂ laser. It was shown that the experimental results obtained are in good agreement with the proposed model.