Comparative Study On Different Measuring Methods Of The Surface Residual Stress Introduced By Shot-peening

The residual stress usually occurs in metal parts and components during theirpreparations and applications, which will affects the safe reliability of the metal partsand components, so it need to be effectively measured and controlled. There are manymeasurement technologies of residual stress, however, the consistency of severalmeasurement results by different measuring methods need people to further research.In this paper, a new section curvature method on average residual stressmeasurement was proposed, and the theoretical model was educed based on the elasticmechanics theory. For shot-peened specimens of the quenched and tempered45carbonsteel, the residual stress distribution and average value in shot-peening plastic straininglayer were investigated, respectively using the peeling X-ray, the crack compliancemethod and the new section curvature method, and these three different measurementresults were compared.The residual stress distributing characteristies were obtained by the peeling X-raymethod and the crack compliance method. The results show that the residual stressdistribution in shot-peening plastic straining layer was similar. The plastic strainingdepths obtained by the two methods are820μm and900μm respectively. For thepeeling X-ray method, the maximum residual compressive stress was446.4MPa andoccurred at the depth of120μm, and average compressive stress was280.8MPa in theplastic straining layer. For the crack compliance method, at the depth of300μm thecompressive stress was471.4MPa. The plastic straining depths and the stressesobtained by these two methods have a certain difference. From an engineeringapplication standpoint, the measuring results by the two methods above can beconsidered to be basically accordant. The average residual compressive stress of shot-peening plastic straining layerobtained by the newly developed section curvature method is351.0MPa, which isabout25percent greater than the result by peeling X-ray. The testing stress of peelingX-ray is the rest of the residual stress after peeling and a little lower than the actualvalue. Their difference will decrease under considering the amending for the testingstress of peeling X-ray.