Determination of residual stresses in metallic materials based on spherical indentation strain

Abstract

A spherical indentation strain method was proposed to determine surface residual stress in this study. Through numerical simulation, the effect of the material properties and residual stress on the plastic zone around the indentation was investigated, and the ideal strain measurement region appropriate for diverse materials was identified. Meanwhile, the presence of residual stress in material will cause the strain increment in the strain measurement area near the indentation to change. Based on the relationship among strain increment, residual stress and material mechanical properties, the calibration equation of residual stress for different materials were established. A portable residual stress loading device was developed and combined with the indentation test to calibrate the 316 L and 304 stainless steel of nuclear welding joint material. The reliability of this method was verified, and it provides convenience for the calibration of the residual stress of stainless steel materials.