Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
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Fatigue Crack Growth Behavior in Ultrafine Grained Low Carbon Steel

  • Kim, Ho-Kyung (Department of Automotive engineering, Seoul National University of Technology) ;
  • Park, Myung-Il (Department of Automotive engineering, Seoul National University of Technology) ;
  • Chung, Chin-Sung (Science & technology Research Institute of Hong-Ik University) ;
  • Shin, Dong-Hyuk (Department. Of Metallurgy and Materials Science, Hanyang University)
  • Published : 2002.10.01
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Abstract

Ultrafine grained (UFG) low carbon (0.15 wt.% C) steel produced by equal channel angula. pressing (ECAP) was tested for investigating the effect of load ratio on the fatigue crack growth rate. Fatigue crack growth resistance and threshold of UFG steel were lower than that of asreceived coarse grained steel. It was attributed to the less tortuous crack path. The UFG steel exhibited slightly higher crack growth rates and a lower △Kth with an increase of R ratio. The R ratio effect on crack growth rates and △Kth was basically indistinguishable at lower load ratio (R >0.3), compared to other alloys, which indicates that contribution of the crack closure vanishes. The crack growth rate curve for UFG steel exhibited a longer linear extension to the lower growth rate regime than that for the coarse grained as-received steel.

Keywords

References

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