# Grade 91 강의 크리프 균열성장 거동에 대한 천이영역과 정상상태영역의 상관 관계

Park, Jae-Young;Kim, Woo-Gon;Ekaputra, I.M.W.;Kim, Seon-Jin;Kim, Eung-Seon
박재영;김우곤;;김선진;김응선

• Received : 2015.07.20
• Accepted : 2015.09.04
• Published : 2015.12.01
• 16 68

#### Abstract

A correlation between the transient regime and steady state regime on the creep crack growth (CCG) for Grade 91 steel, which is used as the structural material for the Gen-IV reactor systems, was investigated. A series of CCG tests were performed using 1/2" CT specimens under a constant applied load and at a constant temperature of $600^{\circ}C$. The CCG rates for the transient and steady state regimes were obtained in terms of $C^*$ parameter. The transient CCG rate had a close correlation with the steady-state CCG rate, as the slope of the transient CCG data was very similar to that of the steady state data. The transient rate was slower by 5.6 times as compared to the steady state rate. It can be inferred that the steady state CCG rate, which is required for long-time tests, can be predicted from the transient CCG rate obtained from short-time tests.

#### Keywords

Grade 91 Steel;Creep Crack Growth Rate;Transient Time;$C^*$-Parameter

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#### Acknowledgement

Supported by : 한국연구재단