X80级海洋隔水管埋弧焊接头CTOD试验研究

依据英国BS 7448断裂韧性试验标准,对X80级海洋隔水管埋弧焊接头进行了低温CTOD（裂纹尖端张开位移）试验研究,测试了X80级533 mm×25.4 mm海洋隔水管对焊接头在0℃下焊缝中心和热影响区的CTOD断裂韧性。试验结果表明：0℃下焊接热影响区的CTOD值大于焊缝中心,即焊接热影响区的低温断裂韧性好于焊缝中心;0℃下对焊接头焊缝中心和热影响区的试样中超过半数在启裂时就发生失稳断裂,焊缝中心试样失稳断裂的比例更大,失稳现象与裂纹扩展方向上存在的脆性区域有关,脆性区域越大失稳现象越显著。

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.