1994 年 60 巻 578 号 p. 2207-2212
In order to investigate crack growth characteristics by thermal striping in sodium used for FBR, thermal striping tests in sodium have been conducted using Type 304 stainless steel and its plasma carburized materials. The results showed that the threshold stress intensity factor range, derived from a thermal stress analysis on the condition of plane stress, could predict the final lengths of the nonpropagating cracks. The stress intensity factor range of carburized material increased with the change of properties, especially the modulus of elasticity. Therefore, as the carbon concentration increased, the cracks were produced earlier and the final crack lengths were longer.