VALIDATION OF THE (4δ_t, σ_(22C)) FAILURE CRITERION TO EXPLAIN THE TEST SPECIMEN THICKNESS EFFECT OF A533 GRADE B STEEL IN THE DUCTILE-TO-BRITTLE TRANSITION TEMPERATURE REGION

摘要

In the ductile-to-brittle transition (DBT) temperature region, the specimen thickness B and fracture toughness J_c are correlated (J_c∝B~(-1/2)); this is true even for standardized specimens. This has been described as the test specimen thickness (TST) effect based on the weakest link model; however, it has been pointed out that J_c does not decrease indefinitely as B→∞, which contradicts this effect. This paper is an extension of our recent work on the point that the TST effect on J_c. observed for the Shoreham reactor vessel steel (A533 Grade B) was explained via the difference in crack tip constraint and demonstrating that the (4δ_t, σ_(22c)) criterion can be applied to explain the effect.