低匹配管道焊接接头的安全评定

在给定裂纹尺寸和栽荷条件及材料的力学性能条件下，以欧盟提出的结构完整性评定方法（SINTAP）为依据，对低匹配X56管线钢含缺陷的环向内表面焊接接头进行安全评定，建立了低匹配X56管线钢焊接接头的二级评定曲线。评定结果表明，评定点在曲线范围内，说明该结构是安全的，取代了将焊接接头近似看作均匀低强材料进行评定的方法，提高了评定精度，降低了评定方法的保守度。

Safe assessment for undermatched welded joint of pipeline

Given crack size,load and mechanical property of the material,Structure Integrity Assessment Procedure(SINTAP) sponsored by the European Commission was applied to assessment for undermatched welded joint of the X56 pipeline steel with internal surface flaw at the weld toe. The failure line of level 2 of the welded joint was derived from the tensile test results. The result of the assessment showed that the point(Lr,Kr)was located within this line,so undermatched welded joint (which contained flaw)of the pipeline was safe. The method of assessment using undermatched material was substitued for the method of welded joint considered as the whole joint,thus reducing the conservativeness of assessment and enhancing the safety margins in engineering structures.