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

抄録

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 was evaluated by K_Ia which was obtained by the static analysis of compact test.
2) K_ID determined by the dynamic analysis of compact test was greater than K_Ia, though K_ID became close to K_Ia as K_Ia/K_Q became a unity. K_Q is the stress intensity factor at the crack initiation.
3) No significant difference was observed between K_Ia and K_ca obtained by ESSO and DCB tests, though K_ca, obtained by DCB test tended to be smaller than K_Ia at lower temperatures.
4) K_Ia was smaller than K_Ic in the transition temperature range, while it was greater than K_Id. In the temperature range where K_Ic which was determined from JIC decreased with temperature increase, however, it was smaller than K_Ia.
5) The fracture appearance transition temperature and the absorbed energy obtained by 2 mm V notch Charpy test were appropriate parameters for representing the crack arrest toughness, while the NDT temperature was not.