177-paper-analysis of nature and source of micro-inclusions

1、1AnalysisofNatureSourceofMicroinclusionsinTubeBloomSteelPipesProducedbyHengyangPipeFactyPENGQichun1，CHENBenqiang1，LIGuangqiang1WUHanjun1(1.KeyLabatyfFerrousMetallurgyResourcesUtilizationofMinistryofEducationWuhanUniversi

2、tyofScienceTechnologyWuhan430081China)SHIShaoqing2LIYanghua2XUJingfeng2PENGZisheng2SUNQunbao2NINGJiancheng2(2.HengyangPipeFactyHengyang421001China)Abstract:Thisarticlediscussesthoughlythequantitativechangeparticlesizedis

3、tributionofmicroinclusionsinsteelsamplesbefeLFprocessLFprocessVDprocesstundishtubebloomsteelpipeinHengyangPipeFacty.Theradialdistributionquantitychangeofmicroinclusionsintubebloomtheradiallongitudinalsizedistributionquan

4、titychangealongsteelpipeareanalyzed.Thesourceofmicroinclusionsisdiscussed.Theresultindicatedthatmeasuresshouldbetakensuchasaddingmedeoxidizationaluminumdosageimprovingtundishpowder.Keywds:compactprocessmicroinclusions；ro

5、undbillet1IntroductionTheEAFLFVDHCCprocesssysteminHengyangPipeFactyisapipeproductionlinethathasthespecialacteristics.Itplacesstrictrequirementonthemoltensteelquality.Thisprocessaffectsthefmationofthemicroinclusionsinthem

6、oltenthesizemechanicalbehavithedispersionoftheinclusionscloselyaffecttheproductquality[12].Therefeasystematicstudyisconductedontheprocessmicroinclusionsbehaviindertoguidetheproductiontooptimizethecontroloftheinclusionsto

7、obtainhighqualitytubebloom.2Experimental2.1SteelmakingprocessHengyangPipeFactyhasahizontalcontinuouscastingproductionlineinsuccessionadoptingwiththeEAFLFVDHCCcompactprocesstoproduceroundbillet.LadlerefiningfurnaceVDvacuu

8、mdegassingplantwirefeedersoonrefinefacilityareappliedinsecondaryrefining.Argonblowingintheentireprocessprotectivecastingareappliedintheladle.3good.FromLFtoVDthenumberofthemicroinclusionsincreasedslightly.Thisincreaseisre

9、latedeithertotheoperationalprocesstotheeffectofinsufficientvacuumingtotheinsufficienttimeofvacuuming.ConsequentlytheproductionfacilitymanagementshouldbeenhancedtoinsuretheproperVDtreatmentconditionsufficienttimeofvacuumi

10、ngprocesswhichinturnwouldimprovetheremovalofmicroinclusionsinVDprocess.010203040506070809020μmThepercentagefinclusionswithdifferentparticlesize%LF10AfterLFAfterVDTundishTubebloomSteelpipeFig.2Theparticlesizedistributiono

11、fmicroinclusionsfeachprocessFromLF(afterVD)totundishstagethenumberofmicroinclusionsincreasedsubstantiallywhichindicatestheoxidesintheliningslagdecomposedemittedoxygenintomoltensteeltherefecontaminatedthemolten.Thenumbero

12、fmicroinclusionsinsteelslightlyincreasedfromtundishstagetotubebloomstageindicatingthateitherthemoltenwasnotinsulatedwellfromairwasreoxidizedtherewastundishpowderentrapment[34].Becauseoftherelativelylowdepthofmoltensteeli

13、nthetundishlargeamountoftundishpowdercarryoverlowabilityofabsbingmicroinclusionstheprotectiveslaginthetundishpowderentrapmentreoxidationwererelativelyseveretheamountofmicroinclusionsinsteelincreased.Fromtubebloomstagetos

14、teelpiperollingstagesomeinclusions(suchasMnSAl2O3)aredefmedcrashedbyrollingstresssothenumberofinclusionsslightlyincreased.Theamountsizeofthemicroinclusionschangedinrespectthattheinclusionsaregoingfloatingupinsecondaryref