# 스프링강의 피로크랙 진전거동에 미치는 압축잔류응력의 영향

• 박경동 (부경대학교 기계공학부) ;
• 정찬기 (부경대학교 기계공학부)
• Published : 2003.01.01
• 44 4

#### Abstract

In this paper, the effect of the compressive residual stresses which were obtained under the various shot velocities of shot balls on the fatigue behaviors of a spring steel, were investigated. The examination of CT specimen test were executed with the materials(JISG SUP9) which are being commonly used for the springs of automotive vehicles. As a result, the optimal shot velocity of shot balls were acquired considering the peak values of the compressive residual stresses on the surface of specimen and effect on the speed of the fatigue crack propagation da/dN in stage II and the threshold stress intensity factor range Δ$K_{th}$ in stage I. Also the material constant C and the crack propagation index m in the formula of paris law da/dN= C $({\Delta}K^m)$ were suggested in this work to estimate the dependency on the shot velocity.

#### Keywords

Spring Steel;Shot-peening;Over Peening;Compressive Residual Stress;Fatigue Crack Propagation;Striation

#### References

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