Simulation Of Temperature Field And Stress Field Of Laser Surface Treatment

Laser heat treatment technology is a kind of surface modification technology which uses high energy density laser to improve the comprehensive mechanical properties of metal.Most of the numerical simulation of laser heat treatment adopts circular spot with Gaussian distribution of spot energy,and the center of the spot has the maximum temperature.Compared with conventional quenching hardness,the hardness of laser heat treatment is higher and its wear resistance is greatly improved.In the process of laser heat treatment,the deformation of the workpiece is very small,so it can replace the surface strengthening of some workpieces or local parts which can not or are difficult to complete by other quenching processes.In this paper,the temperature field and residual stress field of nonlinear structural steel are simulated by ANSYS Workbench.The effects of laser parameters,workpiece thickness and scanning path on temperature field and residual stress field are systematically discussed:The temperature field and residual stress field produced by point heat source loading are analyzed.The influence of laser parameters on the results is investigated in the calculation process.The results show that the temperature and temperature gradient in the loading area can be significantly changed by increasing the power density,and the residual compressive stress on the surface can be effectively increased;the size of the spot mainly affects the distribution of temperature gradient and surface residual compressive stress;the smaller the spot radius is,the more uniform the surface residual compressive stress distribution is;the increase of loading time has no obvious effect on the surface residual compressive stress and the depth of residual compressive stress layer Improvement.The results show that increasing the power density can increase the width of the heat treatment area.The higher the power density is,the greater the depth of the residual compressive stress layer is,and the thickness of the residual compressive stress layer is.With the increase of the scanning speed,the temperature change rate is faster,the temperature peak value decreases,and the residual stress has no obvious change The thickness of the residual stress layer decreases and the depth increases.It is found that the influence of the thickness of workpiece on the surface residual stress and residual compressive stress layer can be ignored.Finally,the effects of different scanning methods on the temperature field and residual stress field of the material are discussed.It is found that the temperature field generated by the reciprocating and the same direction loading modes is symmetrical with respect to the transverse section at the center of the material surface,and the loading path has no effect on the residual stress field of the workpiece.