A533B-1鋼の弾塑性破壊じん性および破壊抵抗の評価

抄録

The elastic-plastic fracture toughness J_Ic value and fracture resistance of A533B-1 steel were evaluated using compact type (1/2CT, 1CT and 2CT) specimens. The results obtained are summarized as follows:
(1) According to the standard method of the Japan Society of Mechanical Engineers (JSME), the J_Ic value can be evaluated accurately by using the smaller size of specimens compared with the ASTM method.
(2) The valid J_Ic value becomes constant regardless of stress states or yielding conditions, when J integral is evaluated from a load-load line displacement curve.
(3) As long as the flat fracture preceeds in the midthickness of the specimen, the tearing modulus, T_J(Δa_max), evaluated from the J-Δa_max resistance curve, becomes a material constant for a wide range of Δa_max.
(4) Before the initiation of shear fracture, the following equation can stand;
Δa_ave=0.38Δa_max
Within this region, T_J(Δa_ave) evaluated from the J-Δa_ave resiatance curve becomes constant in appearance. However, as the area of shear lips increases, T_J(Δaave) decreases rapidly.