GSW0324 The measurement and estimation of creep crack growth of a round bar specimen with a circular notch for 12Cr ferritic heat resistant steel

Abstract

A circular notched round bar specimen produces multi-axial stress field when uni-axial stress is applied in the axial direction. This stress field is produced at practical component structure. Therefore the characterization of creep crack growth rate under this condition is important for practical use. For a circular notched specimen of creep ductile material, a creep crack grows in brittle manner. In this paper, a creep brittle material such as 12Cr ferritic heat resistant steel was noticed. High temperature creep crack growth tests were conducted for a circular notched specimen for 12Cr ferritic heat resistant steel. Q^* parameter which predicts creep crack growth rate is derived for this specimen. On the basis of this Q^* parameter, the algorithm of predicting the life of creep crack growth is proposed.