Effect of specimen thickness on creep crack growth properties of 1Cr Mo V steel
Tabuchi Masaaki; Kubo Kiyoshi; Yagi Koichi
Abstract:Creep crack growth tests on very large 5T-CT specimens of 1Cr-Mo-V steel have been conducted in older to clarify the specimen size effect on creep crack growth properties and to contribute to the standardization of test method in VAMAS project. The creep crack growth rate could be correlated with C* parameter except for the initial stage of crack growth. In this stage, crack was considered to propagate under small-scale creep conditions. In the accelerating stage, the crack growth rate was independent of specimen width but was dependent on specimen thickness. As the specimen thickness increased, the creep crack growth rate increased due to the deformation constraint. The estimation method of displacement rate for CT specimens from the creep strain curve of round bar specimens was also discussed. Key Words:creep crack growth, 1Cr-Mo-V steel, large %t-CT specimen, C* integral, small-scale creep, specimen thickness effect, VAMAS project