带内螺纹精密零件的热处理畸变有限元仿真

Finite element simulation of heat treatment distortion of precision parts with internal thread

带内螺纹的精密零件在经历淬火-低温回火的热处理后发生了轻微的畸变,但是对于精密工程而言(如火箭发动机等),这些轻微畸变将会导致后续在装配过程出现无法装配的严重后果。使用有限元软件及其子程序,考虑了应力影响相变和相变塑性,计算得到了热处理过程中的温度场、应力应变场,以及热处理后的残余应力分布和零件畸变,该畸变与生产过程中的装配结果所显示的畸变基本一致。针对装配困难问题,结合数值模拟分析结果,提出了一些改进生产工艺控制零件畸变的建议。

Even though precision parts with internal threads produce slight distortion after heat treatment of quenching and low temperature tempering, it is not accepted for precision engineering, such as rocket engines and so on. Due to that in the subsequent process, these slight distortion might lead to serious consequences of assembly failure. The finite element software and its subroutines were used to calculate the temperature field, stress-strain field, residual stress distribution and distortion of parts during heat treatment process, considering the effect of stress on phase transformation and phase transformation plasticity. The distortion is basically consistent with that shown by the assembly results in the manufacturing process. Aiming at the problem of assembly difficulty, some suggestions to improve production process and finally to control the distortion are proposed combining with the finite element simulation results.