简介:铁矿石经浓盐酸和少量的SnCl2溶液加热到45℃溶解后,用SnCl2-TiCl3还原滴定Fe(Ⅲ),使Fe(Ⅲ)还原为Fe(Ⅱ),再以K2Cr2O7滴定全铁含量。本方法对实验操作温度,试样溶解酸的选择有一定的要求,宜选用非氧化性强酸在30-60℃溶解矿样。
简介:Cr2O3-formingferriticstainlesssteelshavebeenwidelyexploredasintermediatetemperaturesolidoxidefuelcells(SOFCs)interconnects.However,theevaporationofchromiascalemightmigratetoandpoisonthecathode,leadingtodegradationofthecellperformance.Inthisstudy,Ni-Co-Fe-Pcoatingsweredepositedontheferriticstainlesssteelbymeansofacost-effectivetechniqueofelectrolessmethod.Theyareexpectedtobeconvertedinto(Ni,Co,Fe)3O4spinelwithahighelectricalconductivityandCTEmatchwithstainlesssteel,whichcanblocktheevaporationofchromiaformedonsteelsubstrateexposedtothecathodeenvironmentoftheSOFC.TheeffectsofpH,massratioofFeSO4/(FeSO4+NiSO4+CoSO4)andtemperatureofsolutiononthedepositionrate,compositions,surfacemorphologiesandstructuresoftheNi-Co-Fe-Pcoatingswereinvestigated.TheresultsindicatedthatthedepositionrateincreasedwithincreasingpHwhenpHwaslowerthan9andthenreducedwhenpHwashigherthan9.Thedepositionrateincreasedwithincreasingtemperaturewhentemperaturewaslowerthan80℃andthendecreasedwhentemperaturewashigherthan80℃.ThedepositionratedecreasedwiththeincreaseinmassratioofFeSO4/(NiSO4+CoSO4+FeSO4).ThecoatingsconsistedofNi,Co,FeandP.Thephasestructureofthecoatingwasamorphous.
简介:ThehotductilityofFe-36NiinvaralloywithdifferentadditionsoftheelementceriumwasinvestigatedusingaGleeble-3800thermal-mechanicalsimulatoroverthetemperaturerange850-1050℃,andtheimprovementmechanismofthehotductilitywasanalyzedusingacombinationofSEM,EDS,andOM.TheresultsindicatedthatFe-36Niinvaralloyexhibitedpoorhotductilitybelow1050℃,whichwasmainlyattributedtoweakgrainboundariesandtheactionofgrainboundarysliding.However,thealloyswithceriumcontentsof0.016%and0.024%bothdemonstratedsubstantialimprovementinthehotductilityovertheentiretestingtemperaturerange.Theobservedimprovementofthehotductilityofthealloywith0.016%ceriumat950℃andthealloywith0.024%ceriumat900℃wasassociatedmainlywiththegrainboundarystrengtheningandtherestrictionofthegrainboundaryslidingbecausetheadditionofceriumreducedthesegregationofsulfuratgrainboundariesandrefinedthegrainstructure.Theoccurrenceandaccelerationofdynamicrecrystallizationwerefoundtoberesponsibleforthehighhotductilityofthealloywith0.016%ceriumat1000℃andthealloywith0.024%ceriumat950-1000℃asaresultoftherefinementofthegrainstructurebyadditionofcerium.
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:碳钢薄板厂转炉一次除尘采用湿式法除尘,存在以下问题:1、转炉烟气中的灰尘、水汽和混合气体在风机作用下,形成高速气流,严重冲刷、侵蚀风机转子前后端板、叶片。2、转炉烟气中的灰尘附着在转子前盘、后盘和叶片表面,破坏转子动平衡,转子使用周期较短。"3、影响风机轴瓦、偶合器使用寿命,对风机基础也产生较大影响。4、转子在线使用周期短,检修时间长,人力物力消耗巨大,不利于设备管理和降低费用消耗。炼钢保障作业区相关技术人员针对转炉一次除尘风机转子工作特点和工作环境,进行了多方面分析、论证,在转子表面喷涂金属保护层、对转子反冲洗系统进行改进,降低了转子振动,延长了转子使用周期,缩短了检修时间和人力物力财力消耗,避免了转炉烟气中烟尘、水分及腐蚀性气体对转子及叶片表面的冲刷和侵蚀,延长转子使用寿命,提升了设备综合效益。
简介:Thehot-deformationbehaviorofFe-Mn-Ctwinninginducedplasticity(TWIP)steelwasinvestigatedbyconductinghotcompressiontestswithinarecommendedhotrollingtemperaturerangeatvariousstrainrates.Flowresistancecurvesduringhot-deformationwereobtained,andstrainratesensitivitiesandactivationenergiesforplasticdeformationwerecalculatedusingthepowerlaw.ItisfoundthattheadditionofAlandSiclearlyincreasesthepeakstressesforthepresentalloys,especiallyat950℃.ButMnhasaminoreffectonthestress-straincurvesandactivationenergywhenitscontentvariesfrom15mass%to22mass%forthepresentalloys.
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:Resultspresentedinthisstudycontributetoinvestigationofthemicrostructureandmechanicalpropertiesofthehot-rolledFe16Mn0.6Csteelplates.Thesteelplateshavebeenproducedbybeinghot-rolledattemperaturesrangingfrom1100℃to850℃insevenpassesto97.5%reductioninthicknessandthencooledinafurnaceof650℃.Someplateshavebeenannealedattemperaturesrangingfrom300℃to1100℃for5minto60min,andthenfollowedbywaterquenching.Thereareannealingtwinsinthehot-rolledFe16M...
简介:TheFe-Ti-Nmateralloywaspreparedthroughthein-situreactionofnitrogengaswiththeFe-Timelt.ScanningelectronmicroscoperesultsshowthattheparticlesuniformlydistributedintheironmatrixwereTiN.ThedeliberatelypreparedFe-Ti-Nmasteralloywasemployedforthe409Lferriticstainlesssteelinanattempttorefinetheas-castsolidificationstructure.ItwasfoundthattheeffectivenessofFe-Ti-Nmasteralloyonrefiningoftheas-cast409Lferriticstainlesssteelwasaffectedbyadditionlevel,holdingtimeandmeltstemperature.Itwasfoundthattheaverageequiaxedgrainsizedecreasedfrom1503μmto303μm,theproportionofequiaxedgrainzoneincreasedfrom14%to100%withincreasingtheFe-Ti-Nmasteralloyadditionlevelto2.5%.Theproportionofequiaxedgraindecreasedfrom85%to4%asthesolidificationtemperatureincreasedfrom1803Kto1883K.Whentheholdingtimereachedto8min,thesolidificationstructuresof409Lferriticstainlesssteelshowextremepointsintheproportionofequiaxedgrain.Itisclearthatthegrainrefiningefficiencygraduallyfadeawaywiththeincreasingoftheholdingtimeattheverybeginning.However,whentheholdingtimecontinuestoincreaseandexceedstheextremepoint,thegrainrefiningefficiencyoftheFe-Ti-Nmasteralloyrecoveredtoacertaindegree.Theexperimentalresultsmentionedabovehavebeenanalyzedintermsofthermodynamics.Underappropriateconditions,theFe-Ti-Nmasteralloyusedforgrainrefinementofthesolidificationstructureof409Lferriticstainlesssteelmayhavegoodprospectsforindustrialapplications.
简介:ThemicrostructuralchangesofFe83Si4B13amorphousmotheralloyduringtheheatingprocesswereinvestigatedbyLaserScanningConfocalMicroscopy(LSCM),andthephasetransformationwasdeterminedbytheThermo-Calccalculations.ThedifferencesinthemeltingpointsmeasuredbyDifferentialScanningCalorimetry(DSC)andLSCM,andthoseobtainedbyThermo-Calccalculationswerealsodiscussed.ItisfoundthatthemeltingpointsmeasuredbyDSCandLSCMarerelativelysimilar,whereastheonsetandendofthemeltingtemperaturescalculatedbyThermo-CalcsoftwarearehigherthanthosemeasuredbyDSCandobservedbyLSCM.
简介:Thestudyintroducesthechemicalcomposition,mechanicalproperties,physicalpropertiesandproductionprocessesoftheFe-23Mn-2Al-Vausteniticsteel.Investigationsweremadeintotheformationofcracksinthehot-rolledFe-23Mn-2Al-Vsteelplates,withopticalmicroscopy(OM),scanningelectronmicroscopy(SEM)andenergydispersivespectrum(EDS).Theresultshaveshownthatintergranularoxidationinthereheatingfurnaceisthemaincauseofthecracksonthesurfaceofthehot-rolledsteelplates.Thesurfacecrackingcanbelargelyavoidedbycontrollingtheremainingoxygencontentinthereheatingfurnaceandimprovingcontinuouscasting(CC)processestoincreasethethicknessoffineequiaxedgrainlayerofthesteelslabs.