Research on Crack Tip Opening Displacement(CTOD) Experiment of X80 Marine Riser Submerged Arc Welding Joint

According to British fracture toughness test standard BS 7448,the research on CTOD experiment of X80 marine riser submerged arc welding joint under low temperature was performed,and the CTOD fracture toughness of X80 533 mm×25.4 mm marine riser butt joint was tested on the weld center and HAZ under 0 ℃.The results indicated that the CTOD value in HAZ is higher than that of in weld center at 0 ℃,namely fracture toughness is better in HAZ than that of in weld center at low temperature;over half specimen of weld center and HAZ appear unstable fracture on crack-initiation at 0 ℃,the unstable fracture proportion in weld center is larger.The unstable fracture has some connection with brittle zone existed in crack extending direction,the bigger the brittle zone is,the more obvious the unstable phenomena is.