热轧碳钢氧化皮结构、耐蚀性与酸洗行为研究

上海交通大学硕士学位论文热轧碳钢氧化皮结构、耐蚀性与酸洗行为研究姓名：宋璐璐申请学位级别：硕士专业：材料学指导教师：齐慧滨20090101ABSTRACTIE-tABSTRACTIIStudyontheStructure,CorrosionPropertiesandAcid-picklingBehavioroftheOxideScalesonHot-rolledCarbonSteelPlatesABSTRACTHot-rolledCarbonSteelplatesaccountedforlargeproportionofhot-rolledsteelproducts,whichwereusuallyusedforrawmaterialofcoldrollingprocessorsolddirectlytoconsumers.Thecorrosionresistingandpropertyandpicklingperformanceofhot-rolledcarbonsteelplatesbecamethefocusofconcern.Theconditionoftheoxidescaleonthesurfaceofsteel,includingcomposition,structureanddefects,playedvitalimportantroleinitsanti-corrosionandpicklingbehavior.Basedontheproductionprocessofhot-rolledcarbonsteel,theeffectofheattreatmentonthecompositionandstructureofoxidescalewascarriedout.Thelawsofthetransformationofthestructurewereobtained.Byrecoveryinhightemperaturewithcontrolledcoldrateinlabcondition,theclassiccompositionandstructureofhot-rolledcarbonsteelcouldberestructured.Thecorrosionandpicklingbehaviorofdifferentscalewasstudiedsystematicallywithexperimentresultsdemonstratingthattheprotectivityandpicklingpropertyofthescalecouldbealteredbyheattreatment.Byimitationthepicklingconditionoffactoryinlabenvironment,thepicklingbehaviorofplaincarbonsteelandhigh-tensilesteelwereresearched.Furthermoretheeffectofmajorfactorconcerningtemperature,acidconcentrationaswellaspercentageofelongtationonpicklingwasalsoanalyzed.Basedontheresearchabove,anewmethodofjudgingtheterminaltimeofpicklingwasproposed,thatisthelowestpointofE-tcurve.Inconclusion,theexperimentresultsprovidescientificfoundationforadjustmentandoptimizingoftheoxidescalesoastoimprovingtheanti-corrosionandpicklingproperty,forthejudgmentofendingpointofABSTRACTIIIpickling,forthefurtherknowledgeofhigh-tensilesteel’spicklingbehavior,aswellasforsettingthetechnologicalparameterofmanufacturingproduction.Keywords:Hot-rolledCarbonSteel,StructureoftheOxideScales,CorrosionProperties,Acid-picklingBehavior20092252009225200922511.11.1.11-1FeO570Fe2O3Fe3O4Fe1yO[1-3]70012501:4:95[4-6]570Fe1yOFe2O3Fe3O41-1FeO1000Fig.1-1FeObinaryphasediagramandthepostionofoxideinterfaceat1000[7]Fe1yOp1000Fe1yOFe0.95OFe0.85OFe1yOFe1yOFe1yOIIIIIIIIIIVIIIIII2Fe3O4pFe3yO4Fe3O4Fe2Fe3Fe2Fe3Fe3Fe2O3nFe2O3yyFe2O3γFe2O3400αFe2O31-2570IIV[8]IFe/Fe1yOFeFe1yOeFeFe22+→+OFeOFeFeyx−−→+11xy1-11-2570Fig.1-2Thethree-layeredstructureofoxidescalesonpureironat570anddiffusionmechanismIIFe1yO/Fe3O4Fe3O4Fe1yOFeOOFeeFe42432→+++OFeOFexxyOFexyyx−−=−−+−−1431414141xy1-2IIIFe3O4/Fe2O3Fe2O3322332OFeOFe→+−[phone]OFeOFeneFen→+++1-4IVFe2O3/O2Fe2O3O232232162OFeOeFe→+++1-5−→+22221OeO1-6FeFe3O4O2Fe2O3Fe2+eFe2+Fe3+IIO2Fe3+eeIIIIIVFe1yOMetalMulti-layeredOxidescaleGas3Fe1yOFe3O4Fe1yOFe3O4Fe2O3Fe2O3Fe2O3IIIFe2O3IVFe1yOFe1yOIII[8]CSiMnAlPS570Fe2O3Fe3O4Fe1yO[6]Fe2O3/Fe3O41:4Fe1yOFe3O41:4:410:45:451-2Fe1yO[19]600800/1-3[9]1-3Fig.1-3Theschematicofbubbling,openingsandgraphitelayerformedoncarbonsteel41-4900MnSiO[6]Figure.1-4regularitiesofdistributionofMnSiandOinoxidescaleofcarbonsteelin900airatmosphereSiSiFe1yO/Fe1yO/MnFe1yOMnFe1yOMn2Fe2MnFe1yOFe1yO/COCO2570650[10]1.1.21200125034h23mm5Primaryscale1250100057100µmSecondaryscaleTertiaryorternaryscale[11]10005003[10]Fe2O3Fe3O4FeO570FeO[11]1-51-53Figure.1-5Typicalstructureofthreetypesofoxidescaleinthecenterofhot-rolledIFe1yOFe3O4Fe3O4IIFe1yOFe1yOFe1yO/Fe3O4Fe3O4IIIIFe3O4Fe3O4Fe3O4Fe3O4FeFe1yO3Fe1yO6IFe1yOIIIFe1yO[12]1-6CT[10]3III1-63CT[13-14]Figure.1-6Therelationofvarioustypesofoxidescaleandcoolingrateincenterofstripedsteel[13-14]1-7”[10]1-7[10]Figure.1-7Schematicillustrationofthescalestructuresacrossthewidthofahot-rolledsteelstrip[10]1-753SteelFe3O4+Fe3O4/Fe+FeOFe3O4Fe2O37Fe2O3/Fe3O4/Fe1yOFe3O4/Fe1yOFe3O4Fe3O4Fe[10]Fe1-8CTCT1-8CTabCTcCTFigure.1-8SchematicillustrationoftheeffectofCTonscalestructuresa“structureoftertiaryorternaryscale”;b“structureofquarticscaleinlowCT”;c“structureofquarticscaleinhighCT”.1Fe2+Fe2O3CT610CTFe2O30.5µmFe2O3Fe3O41:20CT660Fe2O31.5µmFe2O3/Fe3O41:51:4CT720Fe2O335µmFe2O3/Fe3O41:41:3720Fe2O3720660Fe2O3660610610Fe2O32acb8FeOCTFe3O4Fe2O3FeOCTFe2O3Fe3O4CTFe2O3Fe3O4Fe3O41-8bFeO1-71-84311414141OFeyyxOFeyxOFeyx−−+−−=−−xy1-7FeOFeFeO+→4341-8Fe3O4570570220570FeO/Fe3O4Fe1-xOFe3O4Fe3O4/FeOFeOFeFe3O4SeamFeOFe3O4FeFeOFeOFeOCTFe2O3Fe3O4Fe3O4/FeOFe3O4Fe3O4FeFeOFe[10]Fe3O4CTCTFeOFe3O4Fe3O4Fe3O4SeamFe3O41.1.39Fe3O4Fe2O3Fe1yOFe3O4[15]“”FTCTFe3O41.1.4WeverEngellFeOFe3O4Fe/HCl/FeO[15]FrischFe2O3/Fe3O4/FeOWeverEngellFe2O3Fe3O4FeOHClFeOFe3O4Fe2O311-9/FeFe++Fe→Fe+++2e1-92I1JL1I2JL23I1FeOFe3O4Fe2O31-10FeOFeO101-9FeO/FeOFe++++e→Fe++1-104I2H+H++e→H1-112H→H21-1251-91-101-111-126/AcAAcAc/1-9Frisch[25]Figure.1-9ModifiedelectrochemicalpicklingmodelbyFrisch[25]5701.1.2IIIIIIIIIIIIII30[17]II/Fe3O4FeO85III5011FeOFeOFeOFeO85FeO1-10[16]Figure.1-10Picklingkineticsofthreetypesofoxidescale[16][17]Undercutting/U/CIFe1yOU/CWIIIU/CWIIIU/CI1-11III1-11[17]abU/CWcU/CIFigure.1-11ProposepicklingmechanismsforTypesI-IIIscales[17](a),(b)undercuttingordissolvingthewustitephase;(c)undercuttingalongscale/steelinterfaceFe12IIIFe3O4Fe3O4Fe3O4Fe3O4III3505007405/