Journal of Mechanical Science and Technology

  • 제14권5호
  • /
  • Pages.530-536
  • /
  • 2000
  • /
  • 1738-494X(pISSN)
  • /
  • 1976-3824(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
권호 표지

Effects of Structure and Defect on Fatigue Limit in High Strength Ductile Irons

  • Kim, Jin-Hak (Department of Mechanical Engineering, Kangwon National University) ;
  • Kim, Min-Gun (Division of Mechanical and mechatronices Engineering Kangwon National University)
  • 발행 : 2000.05.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

In this paper, the influence of several factors such as hardness, internal defect and non-propagating crack on fatigue limits was investigated with three kinds of ductile iron specimens. From the experimental results the fatigue limits were examined in relation with hardness and tensile strength in case of high strength specimens under austempering treatment; in consequence the marked improvement of fatigue limits were not showed. The maximum defect size was an important factor to predict and to evaluate the fatigue limits of ductile irons. And, the quantitative relationship between the fatigue limits$({\sigma}_w)$ and the maximum defect sizes $(\sqrt{area}_{max})$ was expressed as ${\sigma}_w^n{\cdot}{\sqrt{area}}_{max}=C_2$. Also, it was possible to explain the difference for the fatigue limits in three ductile irons by introduction of the non-propagating crack rates.

키워드

참고문헌

  1. Fukuyama, K., Hasegawa, N., and Nishikawa, Y., 1993, 'The Effects of Matrix Structure on Fatigue Life Distribution of Spheroidal Graphite Cast Irons,' Proc. of JSME 70th Conference, Vol. 1, pp. 762-764
  2. James, M. N. and Wenfong, L., 1999, 'Fatigue crack growth in austempered and grey cast irons-stress ratio effects in air and mine water,' Materials Science and Engineering, A265, pp. 129-139 https://doi.org/10.1016/S0921-5093(98)01140-X
  3. Kato, Y. and Takafuji, S., 1997, 'Fatigue Strength of Austempered Ductile Cast Iron in a Long Life Regime,' Transactions of the JSME, Vol. 63, No. 610, pp. 1153-1158
  4. Kim, M. G., 1988, 'Threshold Condition for the Propagation of Short Fatigue Crack,' Transactions of the KSME, Vol. 12, No. 3, pp. 505-512
  5. Lampman, S. R., 1996, Fatigue and Fracture, ASM Handbook (American Society for Materials), Vol. 19, pp. 665-679
  6. Murakami, Y., 1993, Effects of Small Defects and Nonmetallic Inclusions, Yokendo LTD., pp. 233-258
  7. Masahiro, E., 1988, 'Effects of Graphite Shape Size and Distribution on the Fatigue Strength of Spheroidal Graphite Cast Irons,' Zairyo, Vol. 38, No. 433, pp. 19-24
  8. Park, H. S. and Jin, D. K., 1993, 'A Study on Corrosive Wear Characteristics and the Mechanism of Austempered Low-Alloy Ductile Iron,' Transactions of the KSME, Vol. 17, No. 6, pp. 1404-1411
  9. Sugiyama, Y., Asami, K. and Matsuka, S., 1992, 'Quantitative Evaluation Method of Fatigue Limit of Materials with Defects and its Investigation using Ductile Cast Iron,' Transactions of the JSME, Vol. 58, No. 556, pp. 2287-2292