裂纹尖端张开位移(CTOD)试验是深海管线管的一个重要试验项目, 试验通常使用矩形横截面试样, 由于该试样是截取焊接接头的一部分, 并不能很好地反映整个焊接接头的断裂韧度。根据BS 7448: Part2: 1997的要求制备全壁厚试样并在-10 ℃下做低温 CTOD试验, 结果与矩形横截面试样的结果作比较, 发现全壁厚试样的断裂韧度明显优于矩形横截面试样的断裂韧度, 分析发现结果与焊缝的应力状态、化学成分和显微组织的影响有关。全壁厚试样能更真实地反映焊接接头的真实断裂韧度, 更好地指导工程设计。

The crack tip opening displacement test(CTOD)is one of important test projects of the submarinepipeline.Test samples are usually rectangular cross-sectional sample, as the sample is only part of the weldingjoint, and it can not fully reflect the fracture toughness of the welding joint.The full-thickness sample was preparedaccording to BS 7448: Part2: 1997requirements, and the CTOD test was done at a low temperature of-10℃, theCTOD value was compared with the result of rectangular cross-sectional sample, and a better fracture toughness wasgotten by the full-thickness sample, it was found that the CTOD was related to the stress state, chemicalcomposition and microstructure, the fracture toughness of full-thickness sample was obviously better than thesub-size sample, the full-thickness sample could better reflect the true fracture toughness of welding joint and guidefor engineering design.