简介:Steelhasbeenusedasatraditionalwheelmaterialsforalongtime.Before1980’s,over90%wheelsweremadeofsteels.Then,theyieldstrengthofwheelsteelsincreasedgraduallyfrom240-350MPato600MPaorhigher.Theadvancedhighstrengthsteelsbecomethemainwheelmaterials.Since1990’s,DP600hasbeenbroadlyappliedinsteelwheelsoversea.However,therewaslittleresearchofapplicationofhighstrengthsteelwheels(especiallywheeldisc)indomesticwheelindustrial.Inpresence,DP600steelwheelisonlydevelopedinFAWSHbyusingimportedCKD.OtherdomesticsteelwheelmanufacturersdidlittleworkonhighstrengthDP600wheeldiscs.BaosteelwheelsCo.Ltd.isthefirstdomesticcompanyproducingDP600steeldiscsandhasbecometheleadingcompanyinproductionofhighstrengthwheel.BecauseofthehighstrengthofDP600,itsformability,springback,andwrinklehavebecomethekeysofthesuccessfulapplicationofDP600steel.Inthispaper,themetallurgicalandmechanicalpropertiesarefirstlyintroducedandformationproblemsofDP600aredescribedcomparedtotraditionalsteels.Secondly,FLDanalysishasbeendone.Wrinkleandmorespringbackarerecognized.Tosolvetheseproblems,anoptimizedsolutionisdesignedandthegoodresultisobtained.ThetesthasshownthatthefatiguepropertyofsteelwheeldiscsmadebyDP600havebeengreatlyimproved.
简介:Inthisstudy,aroll-bondedUNSN088225alloycladpipelinesteelwasinvestigatedanddevelopedinBaosteel.Basedontherequirementsofanumberofpotentialprojects,weperformedaseriesofstrictevaluationsincludingmechanicalandcorrosiontests.Theresultsshowthemechanicalpropertiesandcorrosionresistanceofthiscladsteeltobeexcellentandtomeettherequirementsofallthedesignparameters.
简介:ThecausestotheoutersurfacefoldingdefectsinN80-Qoilcountrytubulargoods(OCTG)wereinvestigatedthroughtheobservationofthedefects’morphology,microstructureandtheanalysisofthechemicalcompositions.Itisbelievedthatthedefectwasresultedfromtheintrinsicflawsthatoriginallyexistedonthebillet;theywereextendedandoxidizedduringthefollowingreheatingandrollingprocesses.Withmorestrictqualitycontrolandinspectionofthebillet,thedefectcanbepreventedeffectivelyfromoccurring.
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.