0引言国家管网天津LNG二期项目接收站场内外输管道长为700m，规格为1016mm×49mm，材质为API5L-X70，由二期SCV设备出口连接到站内的首站天然气外输管道。该管道焊口共计156道，熔敷金摘要在天然气管道的建设过程中，最需要严格控制质量的工序就是管道组对和焊接。若管道的焊接质量比较差，天然气管道一次合格率低，将会在很大程度上影响管道工程的验收，如果焊口出现多次返修，即使返修合格，但是也影响了焊缝周边HAZ的组织及性能，为今后管道的安全运营留下了非常大的隐患，同时焊口的返修也会增加管道焊接的施工成本。以国家管网集团天津LNG二期项目接收站内外输高压天然气管道安装为背景，先对外输API5L-X70材质管道焊接施工工艺进行概述，再对焊接施工中存在的焊接缺陷进行分析，从质量管理五大要素人、机、料、法、环入手，逐项分析原因，确认防治措施，从而提高天然气管道焊接的整体质量。关键词X70管道焊接合格率中图分类号TE42DOI：10.16759/j.cnki.issn.1007-7251.2023.04.017AnalysisonWeldingDefectsofX70PipelineZHENGQingluDONGWenfengZHAODongkuiZHANGLiangHUKewuYUJiadongAbstract:Intheconstructionprocessofnaturalgaspipelines,theprocessesthatrequirestrictqualitycontrolwerepipelineassemblyandwelding.Iftheweldingqualityofthepipelinewasrelativelypoor,andtheone-timequalificationrateofthenaturalgaspipelinewaslow,itwouldgreatlyaffecttheacceptanceofthepipelineproject.Ifmultiplerepairedoccurtotheweldedjunction,eveniftherepairwasqualified,itwouldalsoaffecttheorganizationandperformanceoftheHAZaroundtheweldjoint,leavingasignificanthiddendangerforthesafeoperationofthepipelineinthefuture.Atthesametime,therepairoftheweldedjunctionwouldalsoincreasetheconstructioncostofpipelinewelding.Takingtheinstallationofhigh-pressurenaturalgaspipelinesinsideandoutsidethereceivingterminalofTianjinLNGPhaseIIProjectoftheNationalPipelineNetworkGroupasthebackground,theweldingconstructionprocessforpipelinesmadeofAPI5L-X70materialforexternaltransmissionwassummarizedfirst,andthentheweldingdefectsexistingintheweldingconstructionwereanalyzed.Startingfromthefivekeyelementsofqualitymanagement,namely,personnel,machinery,materials,methods,andenvironment,thecauseswereanalyze...
