Axis Symmetric Body Laser Transformation Hardening Process Temperature Field And Stress Field Of Numerical Simulation,

Base on the comprehensive analysis of thermal conduction and thermal elastoplastic behavior, reasonable mathematical models have been set up for laser transformation hardening of cylindrical bodies. The temperature field and the stress field during laser transformation hardening of cylindrical bodies were calculated using F.E.M. In aspect of the temperature field, a two-dimension numerical model for laser transformation hardening of metals is given in this paper. The model takes into account the finite dimensions of the workpiece, the temperature dependence of thermal-physical properties of the material, the laser processing parameters, and the surface heat losses due to convection and radiation, and transformation latent heat. Meanwhile, laser transformation hardening is a complex thermal elastoplastic problem. Base on the calculation results of the temperature field and the phase distribution, a numerical model for calculating stress field during laser transformation hardening of cylindrical bodies is developed. This model takes into account the temperature dependence of mechanical properties, the extra strain and stress due to it, and the influence of the microstructural change to stress field, and unloading etc. According to the above models, two calculating programs of the temperature field and the stress field using the finite element method have been compiled using Fortran Language respectively. The transient temperature fields, width and depth of transformation hardening zone of 42CrMo steel cylindrical workpiece during laser transformation hardening have been obtained using calculating program of the temperature field. The calculated results of width and depth of transformation hardening zone are in agreement with the experimental results. The transient stress field and residual stress filed of MoCu nodular cast iron cylindrical workpiece during laser transformation hardening have been obtained. The results are up to the principles of thermal elastoplastic process and some results of previous experiments. The calculated results of thermal elasticity process are consistent with those calculated analytically. In addition, a GUI program is developed using VB language. It is convenient to the data- input. Furthermore, the calculated results are illustrated in graphics mode. By making use of it, spatial and time dependence of temperature field and stress field can be displayed in visual diagrams such as isothermal plot, isoline plot of stress fields, line plot and graphs,etc.