Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Improvement of Fatigue Limit in Spheroidal Graphite Cast Iron with High Strength and Toughness

고강도·고인성 구상흑연주철의 피로한도의 개선

  • Kim, M.G. (Dept. of Mechanical Engineering, Kangwon National University) ;
  • Kim, J.H. (Dept. of Mechanical Engineering, Kangwon National University)
  • 김민건 (강원대학교 기계공학과) ;
  • 김진학 (강원대학교 기계공학과)
  • Published : 1999.03.31
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Abstract

Rotary bending fatigue tests were carried out to investigate the improvement of fatigue limit in annealed and austempered spheroidal graphite cast iron. Main results obtained are as follows. (1) The tensile strength(hardness) of Series C is higher than that of Series B, and fatigue limits are 245MPa in Series C, 230MPa in Series B and 195MPa in Series A, respectively. (2) The fatigue limits of Series B and Series A are mainly governed by the resistance to fatigue crack initiation. Whereas, the fatigue limit of Series C is governed by the resistance to fatigue crack initiation and growth. The defect size and the resistance to crack initiation and growth should be considered to clarify the fatigue properties in spheroidal graphite cast iron. (3) Improvement of fatigue limit by half-austempering is more reasonable than that of full-austempering treatment in multi defective materials as spheroidal graphite cast iron.

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