X65+Inconel 625复合管道焊接接头断裂韧性评定

Evaluation on fracture toughness of welded joint of X65+Inconel 625 composite pipeline

针对复合管道焊接接头的断裂失效现象,采用单边缺口三点弯曲断裂韧性试验,对X65+Inconel625复合管道焊接接头不同区域(焊缝区、熔合区及热影响区)在0℃下的断裂韧性进行测试。通过在焊接接头不同区域预制表面型裂纹和贯穿厚度型裂纹,对比焊接接头不同区域CTOD值的变化趋势,结果显示组织不均匀性对CTOD值分散性的影响较大。研究表明:复合管焊接接头不同区域的断裂韧性不同,其中热影响区的应变时效区CTOD值较高,焊缝区CTOD值较低但分散性不大,而焊缝熔合区和复合层熔合区不但CTOD值较低,且分散性很大,因此熔合区和复合熔合区是X65+Inconel 625复合管道焊接接头的薄弱环节。(图4,表3,参20)

The fracture failure phenomenon of welded joint of composite pipeline was analyzed in this paper.The fracture toughness of welded joint of X65+Inconel 625 composite pipeline in different zones(weld metal zone,fusion zone and heat affected zone)at 0℃was tested by single edge notched three-point bending fracture toughness test.Surface cracks and through-thickness cracks were prepared in different zones of welded joints and compared with the variation trend of CTOD values in different areas of welded joints.The results demonstrate that the structure inhomogeneity has great influence on the dispersity of CTOD value.The research shows that the fracture toughness of welded joints of the composite pipeline varies with zones.Among them,the CTOD value is high in strain aging zone of heat affected zone,and is low with not large dispersity in weld zone,while the CTOD value in weld fusion zone and composite fusion zone are low with large dispersity.So the fusion zone and composite fusion zone are the weak links of the X65+Inconel625 composite pipeline welded joint.(4 Figures,3 Tables,20 References)