Fracture toughness of some materials used in fabricating fixed offshore structures

The results of an investigation of the fracture toughness of weld metals and heat affected zones (HAZ) in steels typical of those used in the fabrication of nodal joints in fixed offshore steel jacket platforms operating in the North Sea are summarized. Data are presented from fracture roughness tests, based upon the crack tip opening displacement concept, on welded joints from 25 mm to 100 mm thick. Weld metal toughness measurements were made on joints manufactured following realistic weld procedures and deposited using 10 different consumables which included shielded metal arc and semi-automatic processes. The results demonstrate that for joints in the as-welded conditions, the HAZ has a significantly higher resistance to brittle fracture than the weld metal. However, after post weld heat treatment the brittle fracture resistance of the weld metal was improved. 20 references.