奥氏体等温淬火Austemper-Gray Iron.ppt

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1、Austemper-GrayIronDecember7,2004SarahBennettJaredCummingsJoshFarrisChrisMcNalleyJohnSchmittObjectiveModifyandanalyzegraphiticflakespacingExploreaus-temperingpossibilitiesofG3000greyironDesiredflakespacingof30mm–80mmTypeAflakeorientationdesiredG3000GreyIronElementWt%C3.4

2、-3.57Si1.80-2.15Mn0.5-0.70P0.020-0.060S0.050-0.150Ni≤0.15Mo≤0.10Cr0.10-0.30Cu0.10-0.40Al≤0.020Ti≤0.022Sn≤0.040V≤0.10TypeAorientationFeSiinoculationAus-TemperingIncreasestrengthandtoughnessModifiesmicrostructureProcedureChemistrywaschosenforpouringofstepbarInoculatedwithF

3、eSiStepbarmoldwaspreparedStepbarwaspoured,sectioned,polished,andanalyzedDifferentcoolingrateswereobservedforchangesinmicrostructureCoolingRatesProcedure(DeterminationofFlakeSpacing)MeasuredcircumferenceCountedintersectedflakesCircumference@5xobjective=1,130mmTentestswer

4、econductedforeverysampleResults(Microstructure)2inchstepbartypeDAlignedorientationResults(Microstructure)1inchstepbar½inchstepbartypeCorientationResults(Microstructure)¼inchstepbarCompletecarbideformationResults(FlakeSize)Thickness(in)211/2AverageFlakeSpacing(mm)66.974.3

5、66.1*The¼inthicknessdidnotcontainanygraphiteflakesProcedure(Austempering)VariantofearlierchartAustenitizingTemperature:oC=730oC+28.0x%Si–25.0x%Mn=771oCResults(Austempering)WhatwewantWhatwegotw/onodulesPearliteResults(Austempering)RecommendationsMoreinoculatecouldhavebeen

6、addedFurtherstudiesonaustemperingVaryingaustenitizingtemperaturesandtimesVarychemistryBettercontrolofquenchingConclusionsDesiredflakespacingof30mm–80mmwasachievedDesiredtypeAorientationwasn’tachievedImproperinoculationCoolingratesAustemperingdidn’tworkQuenchedtoofar?Wron

7、gtemperatures?