Application of FEM correction to measuring the surface residual stresses generated by turning Ti6Al4V tube parts

Abstract:

When measuring the surface residual stresses generated by turning Ti6Al4V tube parts, considering the accuracy, convenience of the measurements and material saving, an appropriate length of the tube was chosen based on the FEM result. When the ratio of the length to the external diameter reaches λ≥50/45 =1.11, the edge effect to the accuracy of the measurements can be neglected. In order to compensate the changes of the residual stresses caused by layer removal, the FEM correction method was used to correct the stress values got by XRD method, and the results revealed that the surface residual stresses generated by turning in both cutting and normal directions were compressive, the magnitude of the residual stress in the cutting direction was larger than that in the normal direction, at the depth of 60 μm, the residual stresses in both directions reduced nearly to 0. The measuring process has revealed that the computation is simple, as proven by FEM, the accuracy of the FEM correction method is much higher than that of the traditional correction method, so it can be applied in practice.