简介:Sprayingtestwereconductedtwicebeforesteelslabswereputintothefurnaceandtheeffectsoftheoxidationresistancecoatingwereinvestigatedandverified.Bycomparingthechangeofslabweight,rollingforceoftheroughingmill&finishingmill,thicknessofoxidefilmonthesurfaceslabsbyanXL-30SEMandacidpicklingspeedofslabswithandwithoutcoating,itwasfoundthattheoxidizationwasteinthefurnacedecreasedby40percentwiththeuseofthecoatingandthecorrespondingyieldcapacitycouldincreaseby0.2percentatleast.Besides,thethicknessofoxidescalefilmonhotrolledproductswasreducedby1.44micrometersandtheacidpicklingtimewasshortenedby6swiththecoatingtechnology,whilethetotalrollingforceofRM&FMdidnotchanged.Furthermore,theapplicationprospectofthistechnologywasalsodiscussedinthispaper.
简介:Inthisstudy,theformabilityoftransformation-inducedplasticity(TRIP)steelisstudiedduringdeep-drawingprocesseswithpreforming.Theeffectsofpreformingontheminimumthicknessofcanareinvestigatedwithaconstitutivemodelaccompanyingstrain-inducedmartensitetransformationinprestraincondition.TheconstitutivemodelhasbeenimplementedintoABAQUS/UMATforanalysisofTRIPsteel-formingprocesses.TheresultsshowthatpreformingslightlyinfluencesthethicknessuniformityofTRIPsteel...
简介:Themicro-characteristicsofthestreakymarksandthecorrespondingsubstratesurfaceofgalvannealed(GA)steelsheetshavebeeninvestigatedusingSEMandFIB.Thestreakymarkareaseemstohavemanycavities,similartocraters,whichscatterlightandmakethesurfaceappeardarkerwhencomparedwiththesurroundingnormalarea.Moreover,itisfoundthattheirregularityordifferenceinsteelgrainsizetendstoaffectthesurfacequalityoftheGAsteelsheets.Duringalloying,thediffusionspeedofZn-Feonthegrainboundaryisfasterthanthatatthecenterofthegrain,whichresultsintheselectiveformationofcrater-likemorphologyinthecoatingareawithlargersteelgrains.DuetothecleargrainboundaryofIFsteel,apparentstreakymarkswillbeformedonthecoatin,iftheIFsteelsurfaceconsistsofrainsofirreularsize.
简介:Withthecontinuousimprovementofproductqualityandfunction,thequalitycontrolofmoldsteelisbecomingincreasinglystricter.Argonprotectionisessentialforensuringcastingqualityduringingotcasting.Thedevelopmentofargonprotectioniningotcastingandtheproductionprocessofenclosedargonprotectionin40tlineisdiscussed,withparticularfocusgiventhefactorsaffectingtheflowofoxygenintheargonprotectioncoverarediscussed.Theinfluenceofsomerelatedfactorsontheoxygencontentisanalyzed.Onthebasisoftheonlinemeasurementsoftheoxygencontent,theoptimizedoperationalapproachesforimprovingtheeffectofargonprotectionaredeveloped.Thiscandecreasetheliquidsteelviasecondaryoxidation,andimprovethequalityoftheingots.
简介:TheeffectofaustenitedeformationonthepearlitemicrostructureofeutectoidsteelwasinvestigatedbyhotuniaxialcompressiontestsusingaGleeble1500thermo-mechanicalsimulator.Theresultsshowedthatthedeformationoftheaustenitephaseacceleratedthetransformationofpearlite,leadingtoasmallercolonysizeandasmallerinterlamellarspaceofpearlite;meanwhile,theorientationofpearlitelamellaebecamemoreheterogeneous,andthelamellarthicknessdecreased.Largerstrainofaustenitewasobservedtoacceleratethespheroidizationprocessofcarbideswithinpearlitecolonies.
简介:High-strengthsteelshavebeenwidelyappliedtoautomotivechassisparts.Inordertoformcomplexshapes,highholeexpansionratesandhighformabilityarerequired.Dualphase(DP)steelhasagoodformability,butapoorholeexpansionrate.Inthiscircumstance,anotherkindofsteelwhichhasamicrostructureofferrite-bainite,ratherthanferrite-martensite,hasbeenfoundtobeanalternativesolution.ItiscalledFBsteel.ThissteelwithSi,CandMnadditionsareappliedinthisstudy.Atwo-stepcooling...
简介:Aplate'sinternalqualityisverycritical,especiallyforboilersandhigh-pressurevessels.Theultrasonictest(UT)isthemaintypeofnon-destructiveflawdetectionforheavyplates,whichisimportantbecauseoneofthemainreasonsforplatedefectsisultrasonicflaws.Thisstudy,basedonBaosteel'spracticalexperienceinthemanufactureofheavyplates,elucidatesthecauseofdefectformationbyanalyzingultrasonicflawtestingmapsandusingspecialequipment,suchasthescanningelectronmicroscope,electronprobeandtheopticalmicroscope.Theauthorputsforwardthefollowingimprovementmeasures:①Ultrasonicflawsarecausedbycentralporosityandsegregation,[H]bubblesandinclusioninslabs.②Ultrasonicflawsaremorelikelytooccurinthebottomandtopofslabsratherthantheotherpositionsinthecastingsequence.Itisclearthatone-quarteroftheinnercamber'sthicknessisaccumulatedinclusion.③Itisclearthatoverheatinginthetundishandtheflowofthecastingmouldhaveaneffectonultrasonicflawscausedbyinclusions.④Softreductionimprovescentralporosityandsegregation,whichdecreasesthenumberofultrasonicflawsintheplate.
简介:Ore-cokemixedchargingisapotentialtechniqueforoptimizingthechargingpattern.Recently,thechargingofsmall-sizedcoke(nutcoke)withtheferrousburdenlayerhasbeenappliedtoreducerawmaterialusageanddecreasecosts.Variousstudiesindicatethatmixingnutcokewithferrousburdencanenhancethereductionkinetics,improvethesofteningandmeltingproperties,andhaveapositiveeffectonthepermeability.Althoughmixedcharging,especiallytheadditionofnutcoketotheburdenlayer,hasbeenusedintheindustryforvariousreasons,themechanismsandsideeffectsforusingnutcokearenotwellunderstood,andthemixingratioremainslimitedinactualblastfurnaceoperation.High-temperatureexperimentalstudieswereconductedtoincreasetheunderstandingofthecomplexprocessofreduction,softeningandmeltingproperties,andpermeabilityinablastfurnacewhenmixingnutcokewithanorelayer.Theeffectofthenutcokemixingratioandnutcokesizewasinvestigatedundervariousreducingconditions.Todescribethereductionprocessesofburdenmaterials,numerousexperimentswereinterruptedatdifferentstagesofthereduction,andthecollectedmaterialswereexaminedbyusingimageanalysis.Thereductiondegreeofmixedcharging(ironoremixingwithnutcoke)wasimprovedwhenusingnutcokeatthetemperaturesof800℃andabove.Thereactionrateofore-nutcokemixedchargingwashigherthanthatofstandardchargingwithouttheuseofnutcoke.
简介:Thisstudyexaminesmechanismsforprovidingnucleitoequiaxedgrainsintheweldsofpureferriticstainlesssteel(FSS).TheadditionofthealloyelementTitopureFSS439causestheprecipitationofTiN,whichcanbenefitthecolumnar-to-equiaxedtransition(CET)ofgastungstenarcwelding(GTAW).Meanwhile,theinitialmorphologyoftheprecipitates,theconcentrationmultiplicationsofTi,N,etc.ofFSS439shouldbecontrolledtoinducetheformationofCETduringtheshortweldingprocess.
简介:ThehotrollingexperimentinvestigatesintotherelationshipbetweenthemicrostructuresandthemechanicalpropertiesofNb-TimicroalloyedsteelswithvariousTicontents.TheresultsindicatethattheeffectofthebainitefractionofNb-TimicroalloyedsteelsontheyieldstrengthofthesteelsisnotrelatedtoTicontent,whiletheslopeoftheHall-PetchrelationshipdecreaseswiththeincreaseofTicontent.Accordingly,theMisramodelfortheyieldstrengthofNb-Timicroalloyedsteelsismodified,andthefactorswhichcausethechangeintheslopeofHall-Petchrelationshiparediscussed.
简介:Theeffectofannealingtreatmentonthemicrostructuresandmechanicalpropertiesofcold-sprayedNicoatingwasinvestigatedbyconductingmicro-hardnessandtensiletestsandusinganormalopticalmicroscope(OM),ascanningelectronmicroscope(SEM),atransmissionelectronmicroscope(TEM)andanelectronprobeX-raymicroanalyzer(EPMA).Theresultsshowthatfollowingtheincreaseoftheannealingtemperature,themicro-hardnessofcold-sprayedNicoatingdecreasesandtheelongationafterfractureincreases,whilethetensilestrengthincreasesbeforedecreasing.Thetensiledeformationandfracturebehaviorchangefromatypicalbrittlefracturetoahybridbrittleandductilefracture,thentoatypicalductilefailure.Itisfoundthatwhenannealedatanelevatedtemperature(e.g.900℃),thegrainstendtogrowabnormallywiththeoxidesspheroidizingandthedefectsagglomeratingattheinterfaces,causingthetensilestrengthreductionofthecold-sprayednickelcoating.Itisalsopointedoutthatthetensilestrengthofthecold-sprayedNicoatingcanbesignificantlyimprovedbytheappropriateannealingprocedures,buttheelongationafterfracturecannotbeclearlyincreasedbecauseitisdifficulttoeliminatethemaindefectsinthecoatingbythefollowingheattreatments.
简介:Textureevolutionofhigh-manganesetwining-inducedplasticity(TWIP)steels(Fe-16Mn-0.6C)duringcold-rollingisstudiedbymeansofquantitativeorientationdistributionfunction(ODF)analysis.Thicknessreductionsofthespecimensduringcold-rollingare10%,20%,30%,50%and65%,respectively.EvolutionoftextureisoftheBrasstype,whichistypicalforlow-stackingfaultenergy(SFE)materials.Thecontributionofdeformationtwinningtothedevelopmentoftextureisclearlyillustratedbythemonotonici...
简介:Cold-rolledmartensiticsteelsheetsproducedoncontinuousannealinglineswithwaterquenchingfacility,haveadvantagesofhighstrengthandlowalloyingelementcontents.Theseareingoodaccordancewiththetrendoflight-weightingandfuelsavingforautomotivesteel.Inthisarticle,acold-rolledmartensiticsteelisstudiedtoinvestigatetheeffectofannealingparametersonitsmechanicalproperties.Itisfoundthatthequenchingtemperatureandtheslowcoolingspeedaswellastheoverageingtempe...
简介:Thechargingpatternmayaffectblastfurnacepermeability,cokeratio,andthefreedomtoselectlow-graderawmaterials.Ore-cokemixedchargingisapotentialtechniqueforoptimizingthechargingpattern.Inrecentyears,chargingsmall-sizedcoke(nutcoke)intotheburdenlayerhasbeenappliedtosaverawmaterialsanddecreasecost.Althoughmixedcharging,especiallyaddingnutcokeintotheburdenlayer,mayhavemanyadvantages,themechanismsandsideeffectsofnutcokeusearenotwellunderstood,andthemixingratioisstilllimitedinindustrialblastfurnaceoperation.Inthisstudy,thestatusofmixedcharging,especiallynutcokeusedinblastfurnaces,wasinvestigated.Acoldflowmodelwasestablishedtostudythepermeabilityofthepackedbedintheblastfurnace"dryzone"underdifferentconditionswiththeaimofbetterunderstandingthemechanismsofmixingcokeandnutcokeintotheburdenlayer.Theeffectofcokesize,mixingcokeratio,layernumbers,andgasflowrateonthepressuredropofthepackedbedwasinvestigated.Theexperimentalresultsshowthatmixingthenutcokeintheorelayersdecreasesthepressuredroptodifferentextentsdependingonmixingratio.
简介:TheeffectofCe,LaandmischmetalonthesolidificationstructureofFe-36Niinvaralloywasinvestigated.Theresultsshowthatgreatamountsofhigh-meltingpointcompounds(Ce2O3,La2O2Sand(Ce,La)2O2S)respectivelyformedinthealloywiththeadditionofCe,Laormischmetal.Basedonthetheoryoflatticemisfit,thelatticemisfitbetweenthe(0001)surfacesofCe2O3,Ce2O2SandLa2O2Sand(100)surfaceofFe-36Niinvaralloywere6.21%,5.77%and5.42%,respectively,whicharerelativelylow.Therefore,Ce2O3,La2O2Sand(Ce,La)2O2Scouldserveasthecoreofheterogeneousnucleation,improvetheequiaxedgrainratio,reducetheequiaxedgrainsizeandrefinethesolidificationstructureofalloy.
简介:Aphysicalmodelwithmercuryasanalogwasdevelopedtoinvestigatetheinfluencesofelectromagneticstirring(EMS)onflowfieldinslabcontinuouscastingwhenthesubmergedentrynozzle(SEN)wascloggedwithdifferentcloggingrates(0,10%,25%,and50%).TheflowfieldinmoldunderdifferentEMScurrents(0,40A,and60A)wasmeasuredbyanultrasonicDopplervelocimeter.Theresultsprovedthattheflowfieldinthemoldwasatypicaldoublerollstructureundernon-cloggingSEN.AstheSENcloggingrateincreased,theflowfieldstructurewastransformedfromadoublerolltoasymmetryflow.Whenthecloggingratereached50%,theupcirculationdisappearedonthecloggedside.Thezoneunderthemeniscusnearthenarrowfacewasanon-flowingarea.EMScouldcorrectbiasflowcausedbySENcloggingandimprovethesymmetryoftheflowfieldduringSENclogging.
简介:Abstract:Inordertounderstandtheeffectofthesolidificationstructureontheformabilityofultralowcarbonferriticstainlesssteel(FSS),thisworkstudiestheridgingphenomenonandthedeep-drawingpropertyindetailandtheresearchmethodwasX-raydiffraction(XRD)andscanningelectronmicroscope(SEM)technique.Theresultshowsthatthecolumnargrainspecimenhadahigherridgingheightthantheequiaxedgrainspecimen,whichwasmainlyattributedtotheformationofgraincoloniesinthecolumnargrainspecimen.Afterfinalrecrystallizationannealing,theequiaxedgrainspecimenobtainedahigh-intensityγ-fibertextureandanexcellentdeep-drawingproperty.
简介:Recrystallizationtextureofsteelplateisaffectedbysubstitutionsolidsolutionandinterstitialsolidsolution.Thisarticlefinishedtexturetestandstampingtestaboutlowcarbonaluminiumkilledsteel,IFsteel,phosphorusstrengthensteel,Si-Mn-Pstrengthensteel.Itcanbefoundthatallkindsofsteelhassimilarintensity{111}textureinpermanentφ=45°aboutlevel10.Interstitialsolidsolutionsteelhad{101}textureandsubstitutionsolidsolutionsteelhad{112}texture.Basedonrecysstallizationprincipleandstampingtest,theeffectofsolutiononrecrystallizationtextureisdiscussed.Itpointoutthatinterstitialsolidsolutionimpediment{111}textureformingandcausedto{101}textureremainedinsteel.Thephenomenonstrengthenanisotropicpropertyandreductionstampingproperty.Similartosubstitutionsolidsolution,itwouldimpediment{111}texturetoo,but{101}texturechangedto{112}texture.