COMPARISON OF HEAT AFFECTED ZONE FRACTURE TOUGHNESS GENERATED FROM CTOD AND WIDE PLATE TESTS

Wide plate and conventional crack tip opening displacement (CTOD) test data obtained from weld heat affected zones (HAZ) of submerged arc welds in a 50mm thick carbon-manganese steel to BS4360 Grade 50E are compared on the basis of crack tip opening displacement (CTOD).Differences in the fracture behaviour between the two tests were apparent and the reasons for this are discussed. However, in the as-welded condition the lower bound toughness distributions were similar. This is attributed to local brittle zones in the HAZ controlling fracture and overriding differences in specimen geometry. The implications of this on a defect assessment procedure based on the strip yield model are discussed.