简介：Oneofthepathwaysforachievingthegoalofincreasingtheefficiencyofcoal-firedpowerplantsandreducingtheemissionofpollutantsandCO2isbyimprovingthesteamtemperatureandpressure.Buttheincreaseofsteamparametersdependonthedevelopmentofnewhigh-temperaturemetalmaterials.ThispaperpresentedtheconstructivesuggestionsoncriticalmaterialsselectionforChina’snewgenerationof700℃cleanandhigh-efficiencycoal-firedboilerbysummarizingtheresearchanddevelopmentsituationofcriticalmaterialsforcoal-firedboilersoperatingat700℃/35MPaoftheEurope,JapanandUSA.

简介：Thisstudyanalyzestheevolutionofcarbidesinthetemperingprocessofanewlydevelopedsemi-highspeedsteelcoldforgedrollwithnitrogenadditionusingatransmissionelectronmicroscope(TEM)equippedwithanenergydispersiveX-ray(EDX).TheprecipitationsequenceofthecarbideswasidentifiedintheentiretemperingprocessanditcanbeexpressedasM3C→M3C+M(C,N)Ⅱ→M(C,N)Ⅱ+M7C3Ⅱ+M23C6.ThesecondaryhardeninginthetemperingprocesswasmainlyduetothedispersedprecipitationoffineM(C,N)Ⅱparticles.ThedissolutionofM3CtemperedathightemperaturesinducedtheprecipitationandcoarseningofM7C3ⅡandM23C6.

简介：EffectsofMo,Nb,Tionmechanicalpropertiesandcorrosionresistanceof22.5%Crferriticstainlesssteelwereinvestigated.TheresultsshowthatMoexistsinferriticstainlesssteelmainlyinthesolutiontreatmentcondition,anditcanenhancesteel’sstrengththroughsolidsolutionstrengthening.InTi+Nbdual-stabilizedferriticstainlesssteel,thesteel’stoughnessdecreasesobviouslybecausecoarseTiNparticlesformandsomemetalliccompoundsprecipitatealongthegrainboundaries.InNbsingle-stablizedferriticstainlesssteel,NbexistseitherinthesolutiontreatmentconditionorintheformofdispersedprecipitatesNb(C,N),whichwillactasthenucleiofprecipitationofthefineσphase.Asaresult,theprecipitationofthecoarseσphasealongthegrainboundarycanbeinhibited,leadingtosignificantimprovementinsteel’stoughnessatalowtemperature.Basedonthese,highcorrosion-resistantferriticstainlesssteelB445Rwasdevelopedforthebuildingcladdingsystem.TestresultsshowthatB445Rhasasuperiorcorrosionresistancetoaustenitic316Linchloridesolution.Besides,ithasagoodformingpropertyandweldability.Allthesemakeitanidealdecoratingmaterialforthebuildingcladdingsysteminseverecoastalregions.

简介：TheeffectofdeformationconditionsondynamicrecrystallizationbehaviorofNb,V,Timicroalloyedhigh-strengthstructuralsteelwasinvestigatedviahigh-temperaturesinglepassreductiontestsonaMMS-300thermomechanicalsimulator,withmathematicalmodelsestablishedforflowstressduringhotdeformation.Theresultsshowthatthedeformationresistancedecreaseswiththeincreaseoftemperatureandisinpowerfunctionrelationshipwiththetemperature.Meanwhile,itincreaseswiththeincreaseofstrainrateandisinlog-logrelationshipwiththestrainrate.Thedynamicrecrystallizationactivationenergyoftestedsteelwasdeterminedtobeabout329.55kJ/mol,295.31kJ/molatpeakandsteadystates.Thepredictionmodelsdevelopedforflowstressindicatedthattheyareingoodagreementwithexperimentalresults.

简介：Thispaperpresentsaconstitutiveframeworkforfiniteelementanalysisofthetruckbeamendcuttingprocess.Forthispurpose,afinitestrainanisotropicelasto-plasticmodel,whichtakesnonlinearkinematicandisotropichardeningintoaccount,ispresented.Threefactorsareinvestigatedtodeterminetheeffectoncuttingquality:radiusofcuttingtools,strengthofmaterialsandrelativeclearanceincutting.Therecommendationsmadehereinarebasedonthesimulationresults.

简介：Coarsening,embrittlementandcorrosionsensitizationinahightemperatureheat-affectedzone(HTHAZ)arethemajorproblemswhen12%chromiumlowcarbonstainlesssteelisbeingwelded,whichinducethedeteriorationoftheimpacttoughnessatalowtemperatureandintergranularcorrosionresistanceproperty.ThisstudyinvestigatesthecorrespondingmicrostructuresinHTHAZwithdifferentchemicalcompositionsandheatinputsthroughthermalsimulationtests.Theresultsshowthatthemartensitecontentincreaseswiththedescendingofferritefactor(FF)whenFFisbelow9.0andheatinputinfluencesthemicrostructureofhighFFsteelinHTHAZ.Martensiteof12%CrstainlesssteelinHTHAZwithonlyNbstabilizationreticularlydistributesatferritegrainboundaries.

简介：Separationisacommonlyobservedphenomenonduringdropweightteartestinginhigh-toughnesslinepipesteels.Severeseparationisharmfulbecauseitmaycausefracturingorburstingofpipes.Inthisstudy,aquantitativemeasurementofseparationwasproposed,andusingthisnewmethod,arelationshipbetweentheseparationandmicrostructurewasdeterminedanddiscussed.Themicrostructuresobservedusingopticalandscanningelectronmicroscopyrevealedthattheseparationwasrelatedtothemixedferriticandbainiticmicrostructures,orrather,itwasrelatedtothecarbonenrichmentinbainite.

简介：InordertosuppressthesurfacecrackinginducedbyCuduringreheatingandhotrollingprocess,Cuenrichmentanditsmigrationatthesteel-scaleinterfacewasinvestigatedduringheatingofsteelcastattemperaturesbetween1000℃and1200℃inN2-O2andN7-H2Oatmospheres.ForoxidationofCucontainingsteel,CuenrichedphasewasformedbythepreferentialoxidationofFeandtheenrichmentandmigrationbehaviorofCudependsontheoxidationtemperature,steelchemistryandatmospherecondition.NiinsteelinducedtheformationofsolidCuandNienrichedphaseatsteel/scaleinterfaceandinscalelayerandtheformationofunevensteel/scaleinterface,whichsuppressestheCuenrichmentbecauseofextrusionofCuenrichedregionbeforetheformationofliquidphase.Ontheotherhand,SnadditionpromotestheliquidCuformationatsteel/scaleinterfaceandpenetrationintograinboundaryofCuenrichedphasebydecreasingsolidustemperatureandsolubilitylimit.Inaddition,foroxidationat1200℃,thebehaviorofCuatandaroundthesteel-scaleinterfacewasfounddependenttoalargeextentonmorphologyoftheoxidescaleformedduringoxidation.Attheearlystageofoxidation,Cu-richphaseformedandaccumulatedatthesteelscaleinterfaceunderbothO2-N2andH2O-N2atmospheres.Astheoxidationproceeded,however,Cuenrichmentatanditsmigrationfromthesteel-scaleinterfacewerevastlydifferentfordifferentoxidizingatmospheres.InthecaseofO2-N2oxidation,anoxidelayerformedinitiallyatthesteelsurface,butsoonafteragapwasdevelopedatthesteel-scaleinterfaceandgrewinitssize,whichpracticallyseparatedthescalefromthesteelsubstrate.Thescalelayerformedunderthisconditionwasporous.TheCu-richphaseinitiallyformedattheinterfacewasfoundmigratingtothescalelayer,leavingnoCu-richphaseattheinterface.InthecaseofH2O-N2oxidation,however,thescalelayerformedwasdenseandtightlyattachedtothesteelsurface,andtheCurich-phasecontinuedto

简介：Withpricesformetalresourcessuchasnickelandmolybdenumsoaring,thereisaheightenedsenseofcrisisconcerningresourcescarcity.WhileType304,themostcommonstainlesssteel,offersexcellentcorrosionresistance,itspriceisaffectedsignificantlybythecostofnickelbecauseofits8%nickelcontent.ThestainlesssteelthathasthesamecorrosionresistanceasthatofType304anddoesnotcontainnickelandmolybdenumhasbeenrequired.JFESteelCorporationhasdevelopedanew21%Cr-0.4%Custainlesssteel,theworld’sfirstferriticstainlesssteel,whichoffersequivalentcorrosionresistancetoType304whilecontainingabsolutelynonickelormolybdenum,tworaremetals.Thenewlydevelopedsteelcontains21%chromiumwiththeadditionof0.4%copper.Thedevelopmentofthesteelisbasedonanewdiscoverythatthepassivefilmsofstainlesssteelscouldbestrengthenedbythesynergyeffectofhighchromiumcontentandcopperaddition.Copperadditionenrichesthechromiumcontentinpassivefilmsafterfieldexposure.Newlydeveloped21%Cr-0.4%CustainlesssteelisadoptedformanyapplicationsasasubstitutionforType304,includingcommercialkitchenware,buildingmaterialsandindustrialmachinery.ThesteelisexpectedtobeanewstandardofaferriticstainlesssteelasasubstitutionforType304.

简介：Cold-rolledhighstrengthsteelsheetsforautomobilescontainmoreMnandSibasedalloyelements,which,underthereducingatmosphereintheannealingfurnace,willgetenrichedonthestripsurface.Sincethefurnacerollersandthestripscontactfrequently,alloyelementsontherollersurfacewillformhardprotuberance.Wecallthisprotuberance"pick-up".Inaddition,withtheincreaseoftheamountofdustinthefurnaceatmosphere,theoccurrenceoffurnacerollerpick-upwillalsoincrease.Throughchemicalreactionandphysicalaccumulationanalysiscombinedwithpracticalexperience,thecausesofpick-upindifferentfurnacesectionswereanalyzed.Methodsofpreventingfurnacerollerpick-upinthehighstrengthsteelsheetprocessinglinewerediscussedandsolutionstoimprovingthestripsurfacequalityinthecontinousannealingfurnacewereprovided.

简介：Thecompositionandproductiontechnologyofthetypeofhot-rolledsteelplateusedintwo-sidedenamelingwerebrieflydescribed.Themicrostructureandmechanicalpropertiesbeforeandafterenamelingwerecontrastivelyinvestigated,andtheprecipitatesinthesampleswereanalyzedusingtransmissionelectronmicroscopeandenergydispersivespectrometer.Theresultsshowtheferritegrainsizeofthesteelplateafterhigh-temperatureenamelfiringtobefine,withalargenumberofTiCandTi4C2S2precipitatesdispersedthroughouttheferritematrix.Aftertworoundsofenamelfiringatatemperaturerangeof800-890℃,itsyieldstrengthcanstillreach342MPa.Theresultsofahydrogenpermeationtestshowthatthehydrogenstoragepropertiesofthesteelplatearemuchbetterthanthoseofordinarystructuralcarbonsteel.Abetterbubblestructureintheenamellayercanbeobtainedbythissteelplate,withnofish-scaledefectsontheenameledsteel-platesurface.

简介：ToresearchtheeffectofZradditiononinhibitingaustenitegraingrowthofTi-bearinglowcarbonsteels,twosteelswithdifferentZrcontentswerepreparedusingalaboratoryvacuuminductionfurnace.TheperformanceofHAZunderweldthermalsimulationswasinvestigated.Theimpacttoughness,microstructureandthesecond-phaseparticleperformanceofHAZunderweldthermalsimulationswereinvestigated.TheHAZtoughnesswasimprovedfrom13Jto87Jbyadditionof0.010%Zrintothesteel,withthefracturemechanismchangingfromcleavagefracturetotoughnessfracture,whichwasmainlyattributedtothesecond-phaseparticlesthatwerepotenttonucleateacicularferriteinHAZduringwelding.Itwasconcludedthatthesecond-phaseparticlesTiOx+MnS,ZrO2+MnSorTiOx+ZrO2+MnSwerenucleatedonZrO2orTiOx(x=1.5,2).Thismethodcanbeappliedtograinrefinementbypromotingtheacicularferriteformationandgrowthduringlarge-scalewelding,asinthecasesofthicksteelplatesrequiringhigherheatinputsduringwelding.

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