Evaluation of Residual Stress in Metal Surface-Strengthened Layers Based on Specimen Deformation After Stripping Partial Substrate

The present work aims to develop a deformation-based method for measuring the residual stress of the strengthened layer. The proposed method determines both the average residual stress in the strengthened layer and the layer's thickness from the change in surface curvature after partial substrate removal. In order to examine the feasibility of the proposed method, the residual stress in the surface-strengthened layers and the layers' thickness of 45 and 16Mn steel specimens subjected to shot-peening are measured using the proposed method and the widely recognized X-ray-electrochemical corrosion stripping method (X-/ECSM). The maximum differences in the residual stress and the thickness between the two methods for the two specimens are 19.7% and 17.6%, respectively. The results of two methods still show acceptable agreement, supporting the feasibility of the proposed method. The newly proposed method offers simpler specimen preparation, better machining accuracy control, and a more streamlined procedure compared to classical methods. However, it is inherently destructive, cannot determine residual stress distribution, and is unsuitable for specimens with complex geometries.