27SiMn钢表面激光熔覆的数值模拟与验证

Numerical Simulation and Verification of Laser Cladding on 27SiMn Steel Surface

在27SiMn钢表面激光熔覆铁基合金粉末,对激光熔覆成形过程中移动高斯热源作用下的温度场利用ANSYS有限元分析软件进行模拟,并建立了三维模型。进行单因素动态模拟,探讨了各工艺参数对温度场的影响。通过设计三水平三因素的正交试验来验证模拟结果的准确性。结果表明:熔池中心的温度最高。当扫描速度一定时,熔池内最高温度与激光功率成正比例关系;当激光功率不变时,激光扫描速度与熔池内最高温度成反比例关系;不同搭接率对熔池内的最高温度影响较为有限。不同时刻下的温度场激光移动热源中心前方的温度梯度大于激光移动热源中心后方的温度梯度。在激光熔覆过程中,当激光功率为2500 W,扫描速度在16 mm/s,搭接率为1/2时,可得到与基体具有良好冶金结合的熔覆层。

Fe based alloy powders were coated by laser cladding on 27SiMn steel surface. The temperature field under moving Gauss heat source was simulated by using ANSYS finite element analysis software in laser cladding forming process, and then the 3-D FEM model was set up. The single factor dynamic simulation was conducted and the effects of various process parameters on the temperature field were discussed. By the design of three levels and three factors orthogonal test, the accuracy of the simulation results was verified. The results show that： the temperature of center of melt pool is the highest. When the scanning speed is constant, the maximum temperature in the molten pool is proportional to laser power. When the laser power is constant, the laser scanning speed is inversely proportional to the maximum temperature in the molten pool. The influence of different lap ratios on the maximum temperature in the molten pool is limited. The temperature gradient in the front of laser moving heat source center of temperature field at different time is greater than the temperature gradient in the rear of laser moving heat source center. During laser cladding, when the laser power is 2500 W, under the scanning speed of 16 mm/s and lap ratio of 1/2, the cladding layer which has good metallurgical bonding with the substrate can be obtained.