304不锈钢激光微抛光的数值模拟与分析

Numerical simulation and analysis of laser micro polishing of 304 stainless steel

为了将激光抛光金属表面的过程可视化,本文建立了脉冲激光抛光304不锈钢的二维瞬态数值模型,模拟了脉冲激光作用下304不锈钢表面形貌的演变过程,揭示了抛光过程中传热、熔化和凝固等物理过程的演化机制。模拟结果表明,与连续激光抛光相比,脉冲激光会使抛光表面产生细小的波纹,但是整体上空间曲率会减小,能够起到一定的抛光效果。在表面形貌的演化过程中,表面起伏较大的区域,由毛细力主导熔池内熔体的流动,其主要作用是消除具有大区率的表面形貌;表面曲率较小的区域,则由热毛细力占据主导地位,其主要作用是促使熔融金属在熔池中重新分布,进一步降低表面的粗糙度。为了验证仿真模型的正确性,通过与实验结果的比较,发现模型熔池深度与实验结果相符合,具有较高的模拟精度。

In order to visualize the process of laser polishing metal surface,a two-dimensional transient numerical model for pulsed laser polishing of 304stainless steel is established in this paper.The evolution process of surface morphology of 304stainless steel under the process of pulsed laser is simulated,and the evolution mechanism of heat transfer,melting,solidification and other physical processes in the polishing process is revealed.The simulation results show that compared with continuous laser polishing,pulsed laser will produce fine ripples on the polished surface,but the overall spatial curvature will be reduced,which can play a certain polishing effect.In the process of surface morphology evolution,the capillary force dominates the melt flow in the molten pool in the area with large surface undulation,and its main role is to eliminate the surface morphology with large area ratio;On the contrary,the thermal capillary force dominates,and its main role is to promote the redistribution of molten metal in the molten pool and further reduce the surface roughness.In order to verify the correctness of the simulation model,by comparing with the experimental results,it is found that the remelting zone depth of the model is consistent with the experimental results,and has a high simulation accuracy.