Fracture toughness for large welded joints in offshore platform

The measuring and testing technique of crack tip opening displacement (CTOD)tests for large welded joints in the offshore platformunder low environmental temperatures of -15℃ were performed in accordance with the BS 7448 standard(part2, 1997).The CTOD tests on the weld metal and heat affected zone were conducted for the welded jointswith a thickness of 54 mm welded by single electrode and twin electrode of submerged-arc welding technology respectively .The testing results provide judgements on whether the joints need postweld heat treatment.