Crack Extension Limit for Fracture Instability Data.

摘要

Fracture instability data, with and without significant stable crack extension, and J/sub IC/ tearing-onset data were studied to find a crack extension limit for the fracture instability data from low alloy steels. New A508-Class 2 data were used to identify both tearing onset (valid J/sub IC/ and fracture instability response curves (fracture toughness was well below J/sub IC/. A fracture instability value of J was considered qualified as a fracture toughness parameter provided that the crack extension at instability was less than or equal to 0.15 mm. Data with greater crack extension were shown to be tearing onset data even if the specimen failed by fracture instability. Thinner-than-standard specimens were found more likely to provide tearing onset data than were standard thickness specimens. 6 refs., 6 figs. (ERA citation 13:056959)