コンパクト試験による構造用鋼材の脆性き裂伝播停止靱性の評価

Abstract

Crack arrest tests such as compact, ESSO and DCB tests were made on SA533B Cl. 1, HT80 and KD32 steels to evaluate the crack arrest toughness. The main results obtained are as follows:(1) The crack arrest toughness could be evaluated by KIa which was obtained by the static analysis of compact test.(2) KID determined by the dynamic analysis of compact test was greater than KIa, though KID became close to KIa as KIa/KQ became a unity where KQ is the stress intensity factor at the crack initiation.(3) No significant difference was observed between KIa and Kca obtained by ESSO and DCB tests, though Kca obtained by DCB test tended to be smaller than KIa at lower temperatures.(4) KIa was smaller than KIc in the transition temperature range, while it was greater than KId. In the temperature range where KIc, which was determined from JIc, decreased with temperature increase, however, it was smaller than KIa.(5) The fracture appearance transition temperature and the absorbed energy obtained by 2mm V-notch Charpy test were appropriate parameters for representing the crack arrest toughness, while the NDT temperature was not.