简介:Thephasetransformationcharacteristicsofahigh-strengthTRIP-aidedmultiphasecold-rolledsteelduringcontinuousheatingatdifferentcoolingrateswerestudiedbymeansofdilatometry,andthecriticaltemperatureswerealsodetermined.Thesampleswerefullyaustenitizedat1050℃andthencooledatdifferentcoolingratesrangingfrom0.5℃/sto100℃/s.Thecontinuouscoolingtransformation(CCT)curveswereobtainedfortheexperimentalsteel.Theexperimentalresultsshowedthatahighcoolingratedepressedtheformationofferriteandpearliteandpromotedtheformationofbainiteandmartensite,leadingtoahigherhardness.Alargeamountofmartensiteinhigh-strengthTRIP-aidedmultiphasecold-rolledsteelcanbeobtainedatcoolingratesinexcessof50℃/s.Theexperimentalresultsprovideguidelinesforcoolingcontrolandheattreatmentinrealsteelproduction.
简介:A0.06%Clowcarbonsteelwasdeformedintorsionoverthetemperaturerange877-917℃ina2%H2-Argasatmosphere.Strainsof0.25-5.0wereappliedatstrainratesofε=0.04s-1andε=0.4s-1tostudytheformationofferritebydynamictransformation(DT)attemperaturesabovetheAe3.ThecriticalstrainforferriteformationbyDTwasaboutε=0.2anditsvolumefractionincreasedwithstrainanddecreasedwithtemperatureabovetheAe3.Averageferritegrainsizesof1.5μmto5μmwereproduced,whichdecreasedwithstrainrate.Atthelowerstrainrate(ε=0.04s-1)reversetransformation(RT)tookplaceduringdeformationonceanincubationtimeofabout40s,wasexceeded.Anincreaseinstrainratefromε=0.04s-1toε=0.4s-1arrestedRTduringtestingatalltemperaturesasthetotaltesttimesdidnotexceed13s.ThepresentworkshowsthatDTisfavoredathigherstrainratesbyincreasingthedrivingforce(i.e.storedenergy)andbysuppressingRT.
简介:Alloyingelements,suchassiliconandmanganese,haveamajorimpactonthephasetransformationpointofsteel.Specifically,manganeseisanelementfortheexpansionandstabilityoftheausteniteregion,whilesiliconcanexpandandstabilizetheferriteregion.Phasetransformationoccursduringthehotrollingprocessforthesteelwithcertainsiliconcontent,whichleadstogreatchangesofthedeformationresistance,therebyaffectingtherollingstability.Consequently,abetterunderstandingofphasetransformationintherollingprocesswillcontributetotheenhancementofproductquality.Inthispaper,theon-linerollingdatawereprocessedbymeansoftheinversecalculationmethod.Inthismethod,thesteeldeformationresistancewithvarioussiliconandmanganesecontentswasobtainedandanalyzedtodeterminethedeformationbehaviorofthesteel,whichcanhelpimprovetheon-linecontrolmodelandenhancethesteelquality.
简介:Theinfluenceofgalvannealingonthetransformationofthesink-rollgroove-markdefectwasstudiedbycomparingthedefectsongalvannealed(GA)coatingwiththoseongalvanized(GI)coating,ItwasfoundthatdefectsonGIcoatingcontainedhighamountsofaluminum,zincdross,andazinc-ironintermetallicoutburststructure,aswellasslightscratchesonthesubstrate.Afterbeinggalvannealed,thealuminumcontentwashigherandtherewasamuchgreateroutburststructure,whichmadethecoatingofthedefectthickerthanthenormalcoating,whilethezincdrossandscratchesonthesubstratehaddisappearedduetozincandirondiffusionduringthegalvannealingprocess.
简介:Thecriticaltransformationtemperatures,Ac1andAc3,ofahot-rolledlow-carbontitaniummicroalloyedsteelweredeterminedasapartofanexaminationofitsphase-transformationbehavior.Austenitedecompositionduringthecontinuouscoolingofthetitaniummicroalloyedsteelwasstudiedbyheatingitto1250℃,coolingitto880℃,holdingfor2s,andthencoolingittoroomtemperatureatdifferentcoolingrates.Thetransformationkinetics(CCTcurve)wascharacterizedaswell.
简介:Aseriesoftestsofdeformation-inducedferritetransformation(DIFT)inalowcarbonsteelwerecarriedoutbytheGleeble-3500hotsimulationmachineatatemperaturerangeofAe3-Ar3.Theoverallstress-straincurvesduringDIFTcanbedividedintothreetypicaltypes:'double-humped','single-humped'and'transitional'.Thepeaksexhibitedinthecurveareinvolvedwithdeformation-inducedtransformationwhichhappenedingrainsoratthegrainboundaries.Accordingtothestress-timecurveandstrain-timecurve,straincapacitydramaticallypostponedthestrain-inducedtransformation,whichleadstothestartofthetransformationrightaheadofthefinishofdeformationandthemajorityoftheferritetransformationprocessmainlyhappenedafterthedeformation.Deformation-inducedtransformationisametadynamictransformationprocesswithdynamicnucleation.
简介:DyPt2filmswerepreparedbyalternatedepositionthinDyandPtlayersonglasssubstratesbyDCmagnetocontrolledsputteringmethod.TheXRDdataindicatedthatforas-depositedDy/Ptfilms,andtheperiodiclayeredstructuresalongthicknessdirectionwereevidencedwithlowangleX-rayscattering.Withincreasingannealingtemperature,thecompoundsofDyPt,DyPt2andDyPt3wereformedsuccessivelyattemperaturerangingfrom300to400℃.ItwasfoundthatthecompositionreactionDyPt+DyPt3→2DyPt2tookplaceat500℃.Afterannealingat500℃for1h,thecompoundsDyPtandDyPt3transformedcompletelyintotheDyPt2compound.