BS 2971-1991 输送流体用碳钢管道二级电弧焊规范

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||BRITISHSTANDARDBS2971:1991IncludingAmendmentNo.1,notissuedseparatelyICS25.160.10NOCOPYINGWITHOUTBSIPERMISSIONEXCEPTASPERMITTEDBYCOPYRIGHTLAWSpecificationforClassIIarcweldingofcarbonsteelpipeworkforcarryingfluidsBS2971:1991Issue2,February1998ThisBritishStandard,havingbeenpreparedunderthedirectionoftheWeldingStandardsPolicyCommittee,waspublishedundertheauthorityoftheStandardsBoardandcomesintoeffecton28June1991©BSI1998FirstpublishedApril1961SecondeditionOctober1977ThirdeditionJune1991ThefollowingBSIreferencesrelatetotheworkonthisstandard:CommitteereferenceWEE/21Draftforcomment90/71692DCISBN0580193845AmendmentsissuedsincepublicationAmd.No.DateTextaffected9773February1998IndicatedbyasidelineinthemarginCommitteesresponsibleforthisBritishStandardThepreparationofthisBritishStandardwasentrustedbytheWeldingStandardsPolicyCommittee(WEE/-)toTechnicalCommitteeWEE/21,uponwhichthefollowingbodieswererepresented:AssociatedOfficesTechnicalCommitteeBritishGasplcBritishNon-ferrousMetalsFederationBritishNuclearFuelsLtd.ElectricityAssociationEngineeringEquipmentandMaterialsUsers'AssociationHealthandSafetyExecutiveHeatingandVentilatingContractors'AssociationInstituteofRefrigerationInstitutionofGasEngineersInstitutionofMechanicalEngineersJointIndustryBoardforPlumbingMechanicalEngineeringServicesinEnglandandWalesNationalAssociationofPlumbing,HeatingandMechanicalServicesContractorsPowerGenerationContractors'Association(BEAMALtd.)StainlessSteelFabricators'AssociationofGreatBritainUnitedKingdomAtomicEnergyAuthorityWeldingInstituteWeldingManufacturers'Association(BEAMALtd.)Issue1,February1998BS2971:1991©BSI1998aSummaryofpagesThefollowingtableidentifiesthecurrentissueofeachpage.Issue1indicatesthatapagehasbeenintroducedforthefirsttimebyamendment.Subsequentissuenumbersindicateanupdatedpage.Verticalsideliningonreplacementpagesindicatesthemostrecentchanges(amendment,addition,deletion).PageIssuePageIssueFrontcoverInsidefrontcoverab12345678to181920221blankoriginal22original2original2original22212223242526272829303132InsidebackcoverBackcoveroriginal2originaloriginaloriginaloriginaloriginaloriginaloriginaloriginaloriginal222bblankBS2971:19911ContentsPageCommitteesresponsibleInsidefrontcoverForeword3Section1.General1Scope42Informationandrequirementstobeagreedandtobedocumented43Parentmetal44Weldmetal55Gasesforshieldingandpurging56Equipment57Weldingprocesses68Backingrings69Jointpreparations610Proximityofwelds611Fusionfaces612Assemblyforwelding713Purging714Damagetoparentmetalbyarcstrikes715Inter-runcleaning716Coldpull717Preheatingforcuttingandwelding718Heattreatmentafterwelding8Section2.Buttjoints19General920Alltypesofbuttjoint921Gussetedbends9Section3.Branchesandsmallboreconnections22General1223Branches12Section4.Sleevejointsandsocket-weldingfittings24General1325Sleevejointdetails1326Socketjointdetails13Section5.Structuralattachments27General1428Weldingprocedure14Section6.Flanges29General1530Weldingneckflanges1531Welded-onflanges15Section7.Inspection32Requirementsforvisualexaminationofcompletedwelds1633Testingofcompletedwelds1634Non-destructivetesting1635Flawlimitations17BS2971:1991Issue2,February19982©BSI1998|PageSection8.Rectificationofunacceptablewelds36Removalofflaws1837Preparationforrewelding1838Rewelding18Section9.Weldingprocedures39General1940Attachmentstothinpipesandbranchwelds19Section10.Welderapproval41General2042Attachmentstothinpipes20AppendicesAClassesofoperatingconditions21BGradesofsteelinBritishStandardsandsimilargradesforpipeinASTMandDINstandards22CTypicaljointpreparations23Tables1Methodsofmakinginitialrootrunsinbuttjoints62Typicallimitsforboredifferenceandalignmentformanualwelding93Classesofoperatingconditions214GradesofsteelinBritishStandards225GradesinASTMandDINstandardsofsimilarweldabilitytoBritishStandardgradesofpipe22Figures1Segmentalbends102Cut-and-shutbend113Sleevejoints134Filletweldsforsleevejoints135Socketjointdetails136Weldingneckflange157Typicalbuttjointpreparationsforusewithbackingrings238Typicalbuttjointpreparationsforusewithoutbackingrings249Typicalset-onbranchwithoutweldpreparation2510Typicalpreparationandassemblyofset-onbrancheswithoutbacking2611Typicalpreparationandassemblyofset-onright-anglebrancheswithtemporarybacking2712Typicalset-inbranchwithoutweldpreparation2813Typicalcurvedor`easysweep'branchjoint2914Typicalset-on(shaped)smallboreconnections3015Typicalset-insmallboreconnection3016Typicalsmallboreconnectionsforpressuresover10barorforrefrigerantsorcorrosivefluids3117Typical`slip-on'welded-onflange3118Typical`slip-on'hubbedwelded-onflange31Issue2,February1998BS2971:1991©BSI19983|||ForewordThisrevisionofthisBritishStandardhasbeenpreparedunderthedirectionoftheWeldingStandardsPolicyCommittee.Itembodiesthetechnicaldevelopmentsthathavetakenplacesincethe1977edition,whichissupersededandwithdrawn.OncommonaspectsthestandardhasgenerallybeenalignedwithBS2633.Therelevantapplicationstandard,where