简介:ItisfundamentallyimportanttounderstandtheinfluenceofstrainonthedensityofdeformationtwinsinTWIPsteelbecausetwinningisitsdominantdeformationmechanism.ThedeformationbehaviorofaFe-30Mn-4Si-3Al-0.097CsteelhasbeeninvestigatedbyX-raydiffraction(XRD),electronbackscatterdiffraction(EBSD)andtransmissionelectronmicroscopy(TEM)techniques.Samplewithanaveragegrainsizeof10μmwasdeformedincold-rollingwithareductionof10%,20%,30%,40%,50%,60%and70%,respectively.Themechanicalpropertiesofthecold-rolledsampleswerefurtherinvestigatedbytensiletests.Theyieldstrength(σy)andultimate-tensile-strength(σUTS)oftheas-preparedsampleis480MPaand850MPa,respectively.However,undercoldrollingdeformation,thetensilestrengthobviouslyincreaseswithanincreaseinrollingreduction.Thesamplewitharollingreductionof10%exhibitsσyof610MPaandσUTSof-1000MPa.Theyieldstrengthandtensilestrengtharefurtherenhancedupto1320MPaand1378MPaforthespecimenwitharollingreductionof70%,regardlessofthepoorductilityof6.7%.ThedeformationmicrostructureswerestudiedbyEBSDandTEMobservations.Itisfoundthat,withincreasingrollingreduction,theaveragedistancebetweendeformationtwinsdecreasesgraduallywhilethedensityofdeformationtwins(thelengthoftwinboundaryinunitarea)exhibitamaximumvalueat40%cold-rolling+tension.Carefullystatisticsanalysisrevealsgrainorientationiscloselyrelatedtothedeformationtwinsandtheunderlyingmechanismgoverningthetwinningisdiscussed.
简介:Opticalmicroscope(OM),scanningelectronmicroscope(SEM),energydispersivespectrometer(EDS)andX-rayDiffraction(XRD)wereusedtostudytheeffectsofrareearthonthemicrostructuralcharacteristicsof55%Al-Zn-1.6%Sihot-dipcoatingsonsteel.TheresultsofOM,SEMandEDSshowedthatbyaddingREintothe55%Al-Zn-1.6%Sibath,thesaw-toothedshapeofintermetallicreactionlayerofcoatingbecamesmooth,andthethicknessoftheoverlayandintermetallicreactionlayerdecreased.TheXRDresultsrevealedthattheintermetallicreactionlayerwascomprisedoftwodifferentregions,abrightphaseclosesttothesteelsubstratewithphasesofFe2Al3andadarkphaseclosesttothemetalliccoatingwithphasesofFeAl3/α-Fe-Al-Si.
简介:研究不同碳源下Al2O3-SiC-C铁钩料的性能。分别以球沥青、焦炭和炭黑为碳源,比较了常温下三者的显气孔率、抗折和抗压强度。结果表明,不同种类碳源将对试样的气孔率和抗折强度产生不同程度的影响。
简介:High-strengthsteelshavebeenwidelyappliedtoautomotivechassisparts.Inordertoformcomplexshapes,highholeexpansionratesandhighformabilityarerequired.Dualphase(DP)steelhasagoodformability,butapoorholeexpansionrate.Inthiscircumstance,anotherkindofsteelwhichhasamicrostructureofferrite-bainite,ratherthanferrite-martensite,hasbeenfoundtobeanalternativesolution.ItiscalledFBsteel.ThissteelwithSi,CandMnadditionsareappliedinthisstudy.Atwo-stepcooling...
简介:Thisstudyaimstoinvestigatetheeffectofthe1-stepquenchingandpartitioning(Q&P)processonthemicrostructureandtheresultingVicker’shardnessof0.3C-1.5Si-1.5Mnsteelbyusingin-situdilatometry,opticalmicroscopy(OM),scanningelectronmicroscopy(SEM),X-raydiffractometry(XRD),andVicker’shardnessmeasurement.Systematicanalysesindicatethatthemicrostructureofthespecimensquenchedandpartitionedat150℃,200℃,250℃,and300℃mainlycompriseslathmartensiteandretainedaustenite.Thedilatometrycurveofthespecimenpartitionedat150℃ispresumablyascribedtotheformationofisothermalmartensite.Intheearlystagesofpartitioningat200℃,thenearlyunchangeddilatationcurveiscloselyrelatedtothesynergisticeffectofisothermalmartensiteformationandtransitionalepsiloncarbideprecipitation.Inthelaterstagesofpartitioningat200℃,theslightincreaseinthedilatationcurveisduetothecontinuousisothermalmartensiteformation.Withfurtherincreaseinpartitioningtemperatureto250℃,thedilatationincreasesgraduallyupto3600s,whichisrelatedtocarbonpartitioningandlowerbainiteformation.Partitioningatahighertemperatureof300℃causesarapidincreaseinthedilatationcurveduringtheinitialstages,whichsubsequentlylevelsoffuponprolongingthepartitioningtime.Thisismainlyattributedtotherapiddiffusionofcarbonfromathermalmartensitetoretainedausteniteandcontinuousformationoflowerbainite.
简介:Inthepresentstudy,sampleswereextensivelycollectedthroughoutthestainlesssteelmanufacturingprocess.Thethree-dimensionalmorphologyofinclusionswasrevealedbynon-aqueoussolutionelectrolysis.Thehighconcentrationofaluminuminferrosiliconcausedtheincrementof[Al]sinsteelandAl2O3ininclusions,whichledtothehighermeltingtemperatureofinclusions.ItwasconcludedthattheapplicationoflowAlferrosiliconandcalciumtreatmentcouldpreventtheformationofAl2O3-richinclusions.
简介:为提高涟钢薄板产品质量,2007年,公司决定对烧结原料进行分开配矿,杂质含量低,烧结性能好的原料进280m2烧结机,所有利废物全部进130m2烧结机和180m2烧结机(以下简称130+180m2),导致利废物由8%提高到18%;同时为了提高烧结矿品位,精粉比例从35%提高到45%。在此情况下,130+180m2烧结机烧结料透气性变差,利用系数下降,能耗升高,保矿压力增大。生产实践证明,提高烧结混合料温度,可以显著减少过湿层的发生,改善料层的透气性能,为实行厚料层烧结提供了有力保障,有效的降低了烧结固体燃料的消耗,提高了烧结生产率。涟钢130+180m2烧结机原在混合料仓安装了蒸汽预热,但预热效果达不到最佳状态。因此,为进一步运用余热回收蒸汽来预热混合料新技术,根据本车间现有的工艺状况,分别在130+180m2分料仓安装蒸汽喷头,通过对分料仓的改造,合理利用余热蒸汽,有效的提高了混合料的温度,取得了良好的经济效益。