3-D Finite element temperature field modelling for direct diode laser hardening of carbon steel

Surface treatments, surface modification and surface engineering are required to improve their wear resistance, erosion resistance, friction resistance and corrosion protection. The laser heat treatment process has been successfully applied to improve hardness, wear and fatigure properties of carbon steels and cast iron. Today several processes are in use to achieve the controlled heating and rapid cooling required for transformation process. Transformation hardening is one of the most attractive processes for direct diode lasers. In this study, the effect of laser beam characteristics such as beam profile, power density, irradiation speed was examined on the micro hardening of carbon steel. In addition, temperature fields for laser hardening of carbon steel are computed by the 3-D finite element method. A finite difference compute model was used to simulate the changes with time of the heat flow. The simulated results were shown in the pseudo-color images on display. Furthermore experimental laser hardening was carried out using a Gaussian laser beam, and the results were in good agreement with the theoretical results obtained by the computer model.