• Title/Summary/Keyword: Small Crack Growth Behavio

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A Study on Growth Behavior of Small Fatigue Crack in 304 Stainless Steel at Elevated Temperatures (고온하 304 스테인레스강의 작은 표면구열의 성장거동에 관한 연구)

  • 서창민;김영호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.1
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    • pp.87-95
    • /
    • 1990
  • Rotating bending fatigue tests of an authentic steel 304 were performed at various temperatures such as room temperature, $538^{\circ}$ and $593^{\circ}C$. The plastic replica method was also applied in order to estimate the fatigue life on the basis of serial observation of small fatigue crack initiation and growth on the pit specimen surface. The fatigue crack growth behavior of 304 stainless steel was investigated within the frame work of elastic-plastic fracture mechanics within a narrow scatterband in spite of different stress levels at elevated temperature as at room temperature. The growth law of small surface crack is determined uniquely by the term. $\DELTA\sigma^{n}a$ where $\DELTA\sigma$ is the stress amplitude, a is the crack length, and n is a constant. It is found that the small crack growth behavior is basically equivalent to the S-$N_{f}$ relationship, where S and $N_{f}$ are stress and number of cycles to failure, and the fatigue life prediction is in good agreement with the experimental results.