简介：High-strengthpipelinesteelandlargediameterlinepipesareoftenusedtoincreasethecapacityoftransportationandreducethecostassociatedwiththeconstructionandoperationoflong-distancegaspipelineprojects.China’sinitiativestoconstructlong-distancenaturalgaspipelineshasbroughtinnewopportunitiesforthedevelopmentofX80linepipes.BaosteelhasdesignedtheoptimumchemicalcompositionofX80withhighniobiumandlowmolybdenumcontent.Inaddition,aweldingexperimentalplatformandafiniteelementmodel(FEM)havesupportedthedevelopmentofX80UOEpipesinanefficientandeconomicalway.TheapplicationandrecentdevelopmentofX80UOEpipeswereintroducedinthispaper.TocomplywiththerequirementsoftheSecondWest-EastGasPipelineProject(2ndWEPP),X80pipelinesteelwithlowcarbonbainitemicrostructurewasdevelopedbyutilizingtheoptimizedcompositionandTMCPprocess.Thematchingweldingmaterial,weldingprocedureandUOEformingprocessesfor1219mmoutsidediameterX80UOEpipeswerealsodeveloped.Morethan340000tofX80UOEpipeswereproducedandappliedinthe2ndWEPP.Furthermore,tomeettheprospectivedemandforlong-distancegaspipelineswithanannualtransportationcapacityofover40billionm3,largersizeX80UOEpipeswith1422mmOD×30.8mmWTweretrialproducedrecently.DWTTperformance,themaintechnicalchallengeforheavierwallpipes,wasimprovedbyusingoptimizedmicrostructuraldesign.ThenewlydevelopedX80pipescanbepotentiallyusedforlargertransportationcapacitypipelinesinChina.