天然气管道螺旋缝附近内部凹坑缺陷分析与评价  

Analysis and Evaluation of Internal Pit defects Near Spiral Weld in Natural Gas Pipelines

作　　者：李强林 杨涛 刘妍 马晓宇 LI Qiang-lin;YANG Tao;LIU Yan;MA Xiao-yu(Shandong Province Gas Pipeline Co.,Ltd.Jinan 250000,China)

机构地区：[1]山东省天然气管道有限责任公司,山东济南250000

出　　处：《全面腐蚀控制》2021年第11期42-47,95,共7页Total Corrosion Control

摘　　要：某天然气管道内检测过程中发现螺旋焊缝附近存在较多内部凹坑缺陷,缺陷情况具有一定的相似性。为充分了解缺陷成因,通过取样分析,对缺陷位置母材采取形貌观察、腐蚀产物分析、金相组织检测、纳米压痕检测等多种手段,分析了缺陷点的理化性能、晶体结构和残余应力,阐明了管道内凹坑缺陷的成因。结果表明,管道缺陷位置发生形变是出现凹坑和残余应力的主要原因,管道在制造过程中因异物挤压造成塑性变形,从而导致管道内凹缺陷,与管道内运行介质及焊接无直接关系。基于缺陷检测结果和成因分析,分别从管道制管、管道运营管理及管道检测等多角度提出相应的控制措施和建议,具有指导意义。During the inspection of a natural gas pipeline,there are many internal pit defects near the spiral weld.By comparison.It is found that the defect has a certain degree of similar.In order to fully understand the cause of the phenomenon,the base metal of pit defect position is taken to observe morphology,analyze corrosion products,detect metallographic structure and nanoindentation in this paper.Meanwhile,the research analyzes the physical and chemical properties,crystal structure and residual stress of the pit defect,based on which the reason of the pit defects is indicated.It is concluded that the defect position deformation is the main reason for the appearance of pit defect and residual stress.The plastic deformation,caused by the extrusion of foreign matters in the manufacturing process,leads to pit defects inside the pipeline,which has no direct relationship with the transmission medium and welding.Based on the results and analysis,the corresponding control measures and suggestions are proposed in the view of manufacture,operation management and pipeline inspection,which have a good guiding significance.

关 键 词：凹坑缺陷 螺旋焊缝 腐蚀产物 金相组织 残余应力 

分 类 号：TQ323.8[化学工程—合成树脂塑料工业]