Numerical analysis of temperature field during laser heating and cooling

Abstract

In this paper, according to the theories of phase transformation, thermal elastoplastic and characteristics of laser quenching, after analyzing the process of isothermal phase transformation and variable temperature phase transformation, heating austenite transformation and cooling martensite phase transformation, and considering the properties of CCT curve, a mathematical model of martensite phase transformation has been obtained and nonlinear heat conduction equation considering the effect of the thermal physical property coefficients and phase transformation have been given, which reflects the hybrid method of F.E.M. (Finite Element Method) and F.D.M. (Finite Differential Method), the transient temperature field during laser quenching on plates and distribution of phase transformation organization have been calculated and analyzed. When calculating the temperature, distribution of austenite and martensite organization and laser hardening region can be calculated too. Comparing the results of calculation with that of experiment, we can make conclusion that our theoretic analysis is valuable for practice and physical coefficients during calculation is significant to the study of laser quenching technology and theory about predicting the material properties.