International Journal of Safety

The Korean Society of Safety (한국안전학회)
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The Effect of Compressive Residual Stresses of Two-stage Shot Peening for Fatigue Strength of Spring Steel

  • Park, Keyoung Dong (School of Mechanical Engineering, Pukyong National University) ;
  • Jung, Chang Gi (Graduate School of Mechanical Engineering, Pukyong National University) ;
  • Kwon, Oh Heon (Department of Safety Engineering, Pukyong National University)
  • Published : 2002.12.01
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Abstract

Recently the steel parts used in automobiles are required to be used under high stress more than ever before due to the need of keeping the weight down. To achieve this requirement of the high strength steel, it must be necessary to decrease inclusion contents and surface defects as like decarburization, surface roughness etc. In this study, the surface conditions are measured to know the influence on fatigue properties by two cases of two-stage shot peening and single-stage shot peening. And for this study, three kinds of spring steel (JISG408l-SUP7, SAE 9254 and DIN 50CrV4) are shaped. This study shows the outstanding improvement of fatigue properties at the case of two-stage shot peening in the rotating bending fatigue test and it results from (1) decreasing the surface roughness (2) unchanging the surface hardness (3) increasing the compressive residual stress. Moreover, results also show fatigue failures originated at the inclusion near the surface, and this inclusion type is turned out to be an alumina of high hardness.

Keywords

References

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