基于BS7910标准的X70钢环焊缝超声相控阵检出埋藏缺陷的安全评定

Safety Assessment for Girth Weld of X70 Pipeline with Embedded Crack Based on BS7910 Standard

为降低建设成本,长输管线通常采用高等级管线钢。对于服役约9年的X70钢管道的一道环焊缝,采用超声相控阵检测,检出5处埋藏裂纹缺陷。基于"合于使用"的原则,采用BS7910:2005标准中的2 B级评定方法进行安全评价。评定结果表明,5处埋藏裂纹缺陷均在标准允许范围内,管道可以安全运行。另外,为探索埋藏缺陷承载安全的表征方法,在缺陷对应的管道外表面贴应变花,以测量缺陷管体外表面的应变。应变测试结果表明,该方法能够表征缺陷尺度与承载能力的关系。

For the sake of construction cost-saving,high grade steels are generally used in long-distance transportation pipeline. For the girth weld with embedded defects in a pipe segment cut in in-situ after the operation of 9 years,5 defects are inspected by ultrasonic phased array testing. Based on the principle of conformity for use,the defects are assessed by BS7910： 2005 standard of 2B level. Evaluation results show that 5 crack defects are within the allowable range,pipeline can run safely. At the same time,to investigate the surface features of load capability of embedded defects,strain rosettes are placed on the outside surface of defects. The strain test results show that,the method can reveal the relation between defect sizes and its load capability.