Ti6Al4V零件铣削加工表面等效残余应力与作用深度的测量

Measurement of Equivalent Surface Residual Stresses and the Depth of Affected Layer on Milled Ti6Al4V Workpiece Surface

为了预测Ti6Al4V零件因铣削加工所致表面残余应力而引起的变形,介绍了一种测量表面等效残余应力及其作用深度的方法。通过对被加工面的背面进行两次腐蚀剥层的操作,使得零件的厚度和中性层的位置发生变化,测量此过程中零件挠度和表面应变的变化,进而计算得到铣削加工引起的零件表面等效残余应力及其作用深度值。通过有限元分析验证,发现有限元计算得到的零件挠度和应变的变化与实际测量值非常吻合,因此可以断定该方法得到的结果是正确的。其可以正确评估铣削加工引起的表面残余应力性质和大小并能准确预测零件铣削加工后因表面残余应力而引起的工件的变形量,从而可以预测零件是否满足精度要求。

In order to predict the deformations caused by surface residual stresses generated by milling of Ti6Al4 V parts, a method for measuring the equivalent surface residual stresses and the effective depth was presented. The material in the surface opposite to the machined surface was removed twice; therefore, the thickness and the neutral layer of the workpiece were changed. Afterwards, the change of the bending deflections and the strains on the machined surface was measured, and then the equivalent surface residual stresses and the effective depth were calculated. FEA（finite element analysis） was used to validate the correctness of this method. The results calculated by FEA correspond well with those measured in the experiments. So it can be concluded that the results got from the method proposed in this paper are correct. It can be used to evaluate the surface residual stresses generated by milling and to predict the deformations caused by surface residual stresses, thereby forecasting whether the parts accuracy can meet the requirement.