输送管环焊缝附近管体缺陷分析

对某管道对接环焊缝进行X射线检测时,发现环焊缝附近管体部位存在多个密集性圆孔缺陷。为了确定这些圆孔缺陷形成的原因,对缺陷钢管进行了宏观分析、X射线检测、金相分析、扫描电镜(SEM)及能谱分析,并对这些试验结果进行了综合分析。分析结果表明,钢管环焊缝附近管体密集型圆孔是焊接过程中焊接金属熔池附近管体材料在高温下熔化后重新结晶过程中产生的气孔缺陷。建议选择强度稍低的焊接材料,并严格控制现场作业,做好焊口预热准备工作,控制好工艺参数,防止焊接熔池体积增大、熔池过热度增加而对焊缝附近母材的性能造成不良影响。

Defect Analysis of Pipe Body Near Girth Weld of Pipeline

It is found that there are several circular defects in the base metal near the girth weld when the pipeline girth weld was inspected by X-ray during the construction of pipeline.In order to find out the cause of these defects,macro analysis,X-ray detection,metallographic analysis,scanning electron microscopy(SEM)and energy spectrum analysis were carried out on the defect steel pipe,and the test results were comprehensively analyzed.The results show that the porosity defect in base metal near the girth weld of steel pipe produced in the process of recrystallization of the base metal near the molten pool during the welding process.It is suggested to select welding materials with lower strength and strictly control on-site operation.he welding joint preheating preparation should be done well,and the process parameters should be well controlled to prevent the bad influence on the properties of base metal near the weld due to the increase of welding pool volume and superheat.