焊缝非匹配海管表面缺陷的安全评定
Safe assessment of surface flaw under mismatched weld in offshore pipeline
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摘要: 采用欧洲共同体提出的工业结构完整性评定方法(SINTAP),对给定裂纹尺寸和载荷条件下的EH36管线钢焊接接头焊趾处的表面裂纹进行评定。由拉伸试验得到的焊缝和母材的屈服强度比值大于10%,确定此次评定适用于SINTAP第二级评定,并给出二级评定图。计算结果表明,在裂纹深度a=2.2 mm,在极限裂纹长度范围内变化的裂纹,其对应的评定点均落在评定曲线定义的范围内。这说明含有该范围内裂纹的缺陷是可以验收的。比较评定结果发现,裂纹深度方向上的变化较长度方向上的变化对评定结果产生的影响更明显。Abstract: According to the results of the CTOD(crack tip opening displacement) test and the SINTAP(structural integrity assessment procedure) suggested by Europe Community,the assessment of the surface flaw at the toe of a weld in pipeline was carried out with the given crack size and load.Based on the tensile test results of the base metal and weld metal,the assessment diagram of Level 2 was constructed.The assessment results indicate that the assessment points are within the region defined on the failure assessment diagrams using Level 2.Therefore,the structure containing definite crack can be accepted.The influence of the changes in the depth on the assessed results are greater than that in the length.