DUCTILE TEARING TESTS OF 316-STAINLESS-STEEL WIDE PLATES CONTAINING WELDMENTS

Twelve wide plate tests have been performed in recent years, as part o f the European Fast Reactor development programme, to examine the infl uence of residual stresses on the fracture behaviour of Type 316 stain less steel plates and weldments. The first ten tests consisted of a st udy of through-thickness cracks and the last two tests addressed the b ehaviour of surface cracks. Results obtained from this series of tests are summarised and the ability of the R6 fracture assessment procedur e to predict the results is reviewed. Significant amounts of ductile t earing under increasing applied load was shown to have occurred in bot h the plain plate and weldment through-thickness crack tests, prior to instability conditions being attained. R6 calculations were shown to conservatively underpredict instability applied loads for all through- thickness cracks tested. The through-thickness crack weldment tests in dicated that residual stresses should be included in predicting initia tion and the earliest stages of crack growth, but that they may be exc luded in predicting the later stages of crack growth leading to instab ility. There was some evidence to suggest however that having to inclu de residual stresses or not may depend on whether the section containi ng the crack is in contained yield or not. A wide plate test of a semi -elliptical crack in parent material, loaded in tension, indicated tha t the global limit load, although being slightly overpredictive in ter ms of applied load, was significantly more accurate than the local lim it load approach.