HydrogenPipingandPipelinesASMECodeforPressurePiping,B31ANAMERICANNATIONALSTANDARDASMEB31.12-2019(RevisionofASMEB31.12-2014)ErratatoASMEB31.12-2019HydrogenPipingandPipelinesParagraphGR-3.9.2wasinadvertentlyomittedfromASMEB31.12-2019,page48.Thecorrectedpagefollowsthiscoversheet.THEAMERICANSOCIETYOFMECHANICALENGINEERSTwoParkAvenue,NewYork,NY10016-5990February2020GR-3.9FORMINGOFPIPECOMPONENTSPipemaybebentandcomponentsmaybeformedbyanyhotorcoldmethodthatissuitableforthematerial,theintendedservice,andtheseverityofthebendingorformingprocess.Whenselectingmaterialforhydrogenservice,considerationshallbegiventotheeffectsofcoldworking,whichmaypromotelowerresistancetoHE,whilehotworkingenhancesresistancetoHE.Thefinishedsurfaceshallbefreeofcracksandsubstantiallyfreefrombuckling.Thicknessafterbendingorformingshallbenotlessthanthatrequiredbytheengineeringdesign.GR-3.9.1BendingRequirements(a)Flattening.Flatteningofabend,thedifferencebetweenmaximumandminimumdiametersatanycrosssection,shallnotexceed8%ofnominaloutsidediameterforinternalpressureand3%forexternalpres-sure.Removalofmetalshallnotbeusedtoachievetheserequirements.(b)BendingTemperature(1)Coldbendingofferriticmaterialsshallbedoneatatemperaturebelowthetransformationrange.(2)Hotbendingshallbedoneatatemperatureabovethetransformationrangeandinanycasewithinatemperaturerangeconsistentwiththematerialandtheintendedservice.(c)CorrugatedandOtherBends.Dimensionsandconfigurationshallconformtoadesignqualifiedinaccor-dancewithpara.IP-3.8.2orpara.PL-3.7,asapplicable.(d)HotBendingandForming.Afterhotbendingandforming,heattreatmentisrequiredforP-Nos.1,3,4,5A,and5Bmaterialsinallthicknesses.DurationsandtemperaturesshallbeinaccordancewithTableGR-3.6.1-1.(e)ColdBendingandForming.Aftercoldbendingandforming,heattreatmentisrequired(forallthicknesses,andwithtemperatureanddurationasgiveninTableGR-3.6.1-1)whenanyofthefollowingconditionsexist:(1)forP-Nos.1through5Aand5Bmaterials,wherethemaximumcalculatedfiberelongationafterbendingorformingexceeds50%ofspec...
