High Power Laser Power Density Distribution In The Heat Treatment Of The Simulation Study

Since the laser was invented in1960, the technique of laser heat treatment broke out of the laboratory and was put into practice widely, along with the development of high-power laser. In the process of surface hardening treatment with laser, the temperature of the heating zone on the workpiece irradiated by laser goes through rapid rise and fall, and the austenite is transformed into the martensite. Hence, the hardness and strength of materials are improved. Kinds of physical phenomena and processing conditions are related to surface hardening treatment with laser. The main factors influencing the treatment are laser output power, scanning speed and the size of laser spot. Meanwhile, the power density distribution of the laser is determined by laser output power and the size of laser spot. The power density distribution varies from the different lasers, and even the same laser does not share the same power density at the different heights. Therefore, it is much important to know the power density distribution of the laser before use, which is theoretical basis for the experimental and study.In2009, a high-power CO2laser was bought by the Kunming University of Science and Technology. In order to obtain the analytic expression of power density distribution of the CO2laser, the laser spot distributions are measured under different power outputs and heights by using thermal paper. And then, experimental images of the laser spot are analyzed through the software MATLAB and a numerical model of laser power distribution is developed to be compared with the experimental spot. The laser surface hardening treatment experiments and calculations of temperature fields are done to verify the obtained analytic expression. The experimental results are in good agreement with the theoretical calculation. This demonstrates that it is feasible to measure the laser power distribution using thermal paper, and the analytic expressions of power distribution can be used as the condition of the theoretical calculation, and is of practical significant.