Measurement of Residual Stress by Cutting Method in Cold Ring Rolling

The residual stress in cold ring rolling could cause great error to parts quality. Due to the complicated formation of residual stress, it's difficult to calculate theoretically. In present study, measurement method is generally used. According to the shape of ring, cutting method is the best method for measuring residual stress. There were 6 stages in cold rolling deep groove ball bearing race. Electric wire discharge machine was used to cut the rings after rolling in each stage. The radius of rings would change after cutting. According to the derived analytic calculation theory of residual stress, the residual stress could be calculated in different rolling stage. The residual stresses were in the range of 110-200MPa. Compared the measurement results from finite element simulation results, the greatest difference was 20%, which was in accepted rang. Through calculation results of six stages in cold ring rolling, it could found that the residual stress increased with the increase of deformation, the straightening stage was benefit to decrease residual stress.