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On the Statistical Properties of the Parameters B and q in Creep Crack Growth Law, da/dt=B(C*)q, in the Case of Mod. 9Cr-1Mo Steel

Mod. 9Cr-1Mo강의 크리프 균열 성장 법칙의 파라메터 B와 q의 통계적 성질에 관한 연구

  • Kim, Seon-Jin (Dept. of Mechanical & Automotive Engineering, Pukyong Nat'l Univ.) ;
  • Park, Jae-Young (Dept. of Mechanical & Automotive Engineering, Pukyong Nat'l Univ.) ;
  • Kim, Woo-Gon (Korea Atomic Energy Research Institute)
  • 김선진 (부경대학교 기계자동차공학과) ;
  • 박재영 (부경대학교 기계자동차공학과) ;
  • 김우곤 (한국원자력연구원)
  • Received : 2010.09.13
  • Accepted : 2011.01.05
  • Published : 2011.03.01

Abstract

This paper deals with the statistical properties of parameters B and q in the creep crack growth rate (CCGR) law, da/dt=B$(C^*)^q$, in Mod. 9Cr-1Mo (ASME Gr.91) steel which is considered a candidate materials for fabricating next generation nuclear reactors. The CCGR data were obtained by creep crack growth (CCG) tests performed on 1/2-inch compact tension (CT) specimens under an applied load of 5000N at a temperature of $600^{\circ}C$. The CCG behavior was analyzed statistically using the empirical equation between CCGR, da/dt and the creep fracture mechanics parameter, $C^*$. The B and q values were determined for each specimen by the least-squares fitting method. The probability distribution functions for B and q were investigated using normal, log-normal, and Weibull distributions. As far as this study is considered, it can be appeared that B and q followed the log-normal and Weibull distributions. Moreover, a strong positive linear correlation was found between B and q.

Keywords

Creep Crack Growth;Creep Crack Growth Rate Law;Probability Distribution Function;Mod. 9Cr-1Mo Steel

Acknowledgement

Supported by : 부경대학교

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