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Vol.45, No.11, 593 ~ 602, 2007
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| Title |
| The Effects of Microstructure and Temperature on Fatigue Crack Growth Behavior of Type 347 Stainless Steels |
| 이종만 Jong Man Lee , 김만원 Maan Won Kim , 권숙인 Sook In Kwun , 이봉상 Bong Sang Lee , 윤지현 Ji Hyun Yoon |
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| Abstract |
| The effect of the microstructure and temperature on the fatigue crack growth behavior of AISI type 347 stainless steels(SS) has been studied. The isothermal FCGR (fatigue crack growth rate) of the type 347 SS increased as the temperature increased. The FCGRs of the type 347 SS at various temperatures were slightly lower than those presented in the ASME code. Even though the effect of the microstructure on the crack growth rate was not significant in the steady-state FCGR region, it was observed that the ΔK(th) of a specimen with a high precipitate density was higher than that of a specimen with a low precipitate density. It was deduced that the difference in ΔK(th) resulted from a difference in the mean free path length of a dislocation movement. The FCGRs were higher than the isothermal FCGR when a thermal stress and a mechanical stress were imposed on the type 347 SS coincidently. |
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| Key Words |
| Fatigue crack growth rate, Threshold stress intensity factor, Type 347, Austenitic stainless steel, Niobium carbonitride, Thermo-mechanical Fatigue, TMF |
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