パンチ加工が及ぼす疲労強度特性への影響

抄録

In order to clarify the effect of punching process on fatigue strength properties of thin steel sheets, tension-compression fatigue tests were conducted. For the fatigue tests, processed and unprocessed specimens were prepared. The unprocessed specimen had the same shape as the processed specimen but had no punching process effect on the steel. Before the fatigue tests, hardness and residual stresses were measured. From the measurements, hardening near the punching processed surface, and positive residual stress were obtained. From the fatigue tests, fatigue lives and the fatigue crack behavior were obtained. By using these results, the effects of punching process were discussed.