激光熔覆镍基合金温度场和应力场数值模拟

文中采用SYSWELD软件分别对激光单道和搭接熔覆过程进行模拟分析. 结果表明,激光熔覆处理时经历了快速加热、快速冷却的过程,具有较高的过热度,单道处理时熔覆层表面中心点峰值温度最高,可达2 589 ℃;随着远离熔池中心,各点峰值温度逐渐降低. 激光单道处理后,熔覆层内受拉应力,最大值出现熔覆层与基体交界处,热影响区受压应力. 搭接处理后第一道熔覆层仍受拉应力,但拉应力值明显降低,最大值在热影响区. 由于第一道熔覆的预热作用,第二道各点峰值温度均高于单道处理,应力最大值出现在靠近熔覆层底部位置,而热影响区受压应力.

Numerical simulation on temperature and stress fields of laser cladded Ni-based coating

In this paper, the software SYSWELD was used to simulate the single track and overlapped laser cladding process. The results show that the molten pool undergoes a rapid heating and cooling process with high superheat degree during the laser cladding. During the single track laser cladding, the peak temperature of the center point on the molten pool surface is highest, reaching 2 589 ℃. In addition, the peak temperature decreases as the distance is far away from the molten pool center. After the single track laser cladding, the cladding coating is in the tensile stress status and the maximum value locates at the interface between the cladding coating and the matrix, while the heat affected zone is in compressive stress. During the laser overlapped cladding process, the first cladding layer experiences tensile stress, but the tensile stress value decreases obviously and the maximum stress locates at the heat affected zone. Furthermore, because of the preheating from the first track to the second one, the peak temperatures of the points on the second cladding coating are higher than those of the single track The maximum tensile stress appears at the bottom of the cladding coating while the heat affected zone is in compressive stress.