Abstract
The long-term creep crack growth tests of more than 10000 hours were conducted using CT specimens of 316 stainless steel at 650°C and 750°C. The crack growth rates in the long-term tests were faster than those in the short-term tests at 650°C. This difference was caused by the difference in creep fracture mode. The creep crack which gave wedge-type or cavity-type intergranular fracture showed higher growth rate than that under transgranular fracture. The difference in crack growth rate between the wedge-type intergranular and transgranular fracture modes was attributed to the effect of creep ductility. The crack growth under cavity-type fracture, which was observed at higher temperatures and longer creep tests, should be investigated by taking into account the accumulated creep damage ahead of the crack tip.
