简介:Inthispaper,therecentstateandproblemsofthesinkrollinCGLaredescribed.Severalmethodsofincreasingitsoperationallifespanareintroduced,suchassurfacecoatingtechnologyandsleevematerialtechnology.Fundamentallytheycannotsolvetheproblemsofsurfacequalitycausedbythecontactbetweenstripandroll.Onthisbasis,thenewlydevelopedprincipleandsolutionsforhotdipgalvanizingtechnologywithoutsinkrollarehighlyemphasized,theyareFloatTechnology,Electromagneticpumptechnology,Electromagneticenclosedslotbyhigh-frequencyAC,Electromagneticenclosedslotbyhigh-frequencyDC.Acomparisonamongtheirfunctionsandcharacteristicsismadeandthepossibilityofitsapplicationisalsodiscussed.Finallyitcomestoaconclusionthatelectromagneticenclosedslotrepresentsthedirectionofacontinuoushot-dipgalvanizingsteelstripinthethe21stcentury.Ithasaverybroadapplicationprospects.BaosteelTechnologyCenterisfocusedontheresearchanddevelopmentofthistechnology.Astechnologyadvances,industrialapplicationsispossible.
简介:IncombinationwiththeprocesstechnologyandequipmentatTangsteelColdRollingMill’s3~#galvanizedline,themechanismofdefect-formationofthestripsurfaceinthehotdipgalvanizedcoatinghasbeenanalyzed.Throughaseriesofreformabouttechnologyandequipmentgoodsolvedthedefectshasbeenfocusedoninthispaper.Thestripsurfacequalityinthehotdipgalvanizedcoatinghasbeenimprovedalot.
简介:Improvingthegalvanizabilityofhighsiliconadvancedhighstrengthsteels(AHSS)isapracticaltechnicalchallenge.Inthisstudy,spotdefectsonanindustrialhotdipgalvanized(GI)sheetofanAHSSwith1.5%Sihasbeenstudiedin-depth.ThesurfacemorphologiesofspotdefectsbeforeandafterpartialandcompleteremovaloftheZnlayer,aswellastheinterfacebetweentheoutermostcoatinglayerandthesheetsubstratewerecharacterizedusingopticalmicroscopy(OM),scanningelectronmicroscopy(SEM),a3-Dopticalprofiler,energydispersivespectroscopy(EDS)andfocusedionbeam(FIB)analysis.Themostoutstandingspotdefectonthenormallycoatedareaofthesteelsheethasadiameterofapproximately500μm,withthefollowingcharacteristics.Inthecentralregionofthespotdefect,ZnisbarelycoatedandthesheetsubstrateiscoveredbyathinsiliconoxidefilmwithdispersedZn-Feintermetallics.Attheperipheryofthespotdefect,aburststructureofZn-Feintermetallicsformsonthesheetsubstrate.OutsidethespotdefectwheretheZnlayerisnormallycoated,thereisacontinuousFe2Al5inhibitionlayerbetweentheZncoatingandthesheetsubstrate.Theseresultsindicatethatasiliconoxidefilmformsonthesubstrateduringannealingpriortohotdipping,thuspreventingtheformationoftheFe2Al5inhibitionlayerduringhotdipping.ThiscausesspotdefectsonhighSiAHSSsheets.
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.