铁合金铸造(铸铁铸造类英语培训材料)真的很好.ppt

铁合金铸造(铸铁铸造类英语培训材料)真的很好.ppt

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FerrousCastingAlloysFerrousCastingAlloysIntroductionIron-CarbonPhaseDiagramBasicCastIronMetallurgyCastIronsMicrostructuralFormationSolidificationSpecifications,propertiesandapplicationsCastSteelsFerrousCastingAlloysLiterallyiron-basedcastingalloysCastIronironalloywithsignificantCandSiGrayDuctileCompactedGraphiteAustemperedDuctileMalleableSpecialtyCastSteelironalloywithlowCandSiFerrousCastingAlloysAnderson,p.269IronCarbonPhaseDiagramASMVol.3,p.2.110IronCarbonPhaseDiagramPointsofnotePhasechangesofpureiron（）Eutectic,eutectoid&peritecticreactionsGraphiteisstable,butmetastableFe3C（akacementiteorironcarbide）occursfrequentlyDesiredforcastirons:

graphiteeutecticproduct,cementiteeutectoidproductIronCarbonPhaseDiagramWhatmicroconstituentsarepossibleoncoolingfromaustenite?

DependsoncoolingratePearliteBainiteupperandlowerMartensiteIronCarbonPhaseDiagramASMVol.3,p.2.110PearliteLowestrelativecoolingratesAteutectoidcomposition（0.78%C）Theeutectoidproductferrite+cementitegrowinlamellarformNucleatesatprioraustenitegrainboundariesPearliteSamuels,p.317PearliteSlowestrelativecoolingratesAteutectoidcomposition（0.78%C）Theeutectoidproductferrite+cementitegrowinlamellarformNucleatesatprioraustenitegrainboundariesCoolingratedeterminesinterlamellarspacingLowerratescoarsespacingsMoremassivecementiteplateletsmeanlowerstrength&bettermachinabilitys2023HRCHigherratesfinespacingsHigherstrength&poorermachinabilitys3035HRCPearliteRC&W,p.361PearliteOffeutectoidcompositionHypoeutectoidFerritenucleatesatgrainboundariesPearlitegrowsateutectoidtemperatureHypereutectoidCementitenucleatesatgrainboundariesPearlitegrowsateutectoidtemperatureCastironsare（extremely）hypereutectoidWelldiscussthisfurtherwithsteelsBainite&MartensiteBainiteIntermediatecoolingratesFerrite“lath”withFe3CTwotypesUpperbainite-“lowerintermediate”coolingrateLowerbainite-“higherintermediate”coolingrateMartensiteHighestcoolingrates（quenchingrequired）Carbon-austenitesolidsolutionUniquecrystalstructureBCTTheseareunimportantincastironmetallurgyIronCastingsBriefHistory3000BCFirstcastobjects（copper）600BC-Firstcastironobject（a600lb.tripod）castinChina1500ADSandfirstusedamoldingmedia1646FirstAmericanironfoundrynearBoston1722Malleableironisdeveloped1750ParliamentprohibitsironcastinginAmericancolonies1794Cupolameltingdeveloped1863Metallographydeveloped,metallographsbecomeavailablein19111899Firstelectricarcfurnacebeginsproduction1900BrinellhardnesstestintroducedIronCastingsBriefHistory1906Firstinductionfurnaceinstalled1918Firstautomatedfoundrygrenadehulks1930Firstcorelessinductionfurnaceinstalled1943Ductileirondiscovered;patented&commercializedin1949（Fordswitches100%ofcrankshaftproductiontoductileironin1951）1957Vertically-partedmoldingisinvented（DISA）1962Firstautomatedgreensandmoldingmachine1976Compactedgraphiteironisdeveloped1990KeyCoreprocessemployedforprecisiongrayironcastingsSource:

ModernCasting,November2002CastIronsCharacterizedbyfreegraphiteinmatrixofferriteandcementite（eutectoidpearlite）TypesaredifferentiatedbytheformofthefreegraphiteICH,p.145CastIronsCharacterizedbyfreegraphiteinmatrixofferriteandcementite（ferriteorpearlite）TypesaredifferentiatedbytheformofthefreegraphiteEssentiallyFe-C-Sialloy（ternary）BasicCastIronMetallurgyFe-Fe3C-Si2%SiICH,p.135BasicCastIronMetallurgyEutecticcompositionvarieswithsilicon（andphosphorus）contentCarbonEquivalentCE=%C+（%Si+%P）/3CEateutectic=4.3Grayironishypoeutectic（CE=3.94.1）Ductileironishypereutectic（CE=4.34.6）BasicCastIronMetallurgyCbecomeslesssolubleinausteniteastemperaturedropsbeloweutectictemperatureCdiffusestographiteparticlesGrayIronFullypearliticmatrixaround（normal）coarseflakesFerritematrixaroundfinegraphiteflakesDuctileIronFerrite“bullseye”aroundnodulesRapidcoolingresultsinfullypearliticmatrixAteutectoidtemperature,remainingcarboninaustenitebecomespearliteBasicCastIronMetallurgyChillcastironcooledtoorapidlyformsaustenite-carbideeutectic（whiteiron）insteadofaustenite-graphiteeutecticCheckforchillbypouringachillwedgeMeasureofsectionthicknessthatcanbecastfreeofcarbideCompositioneffectsdepthofchillHigherCE=thinnersectionsBasicCastIronMetallurgyShrinkagethreecomponentsLiquidcontractiononcoolingSolidificationvolumetricchangeonchangingfromliquidtosolidSolidcontractiononcoolingControlliquidandsolidificationshrinkagebymaintainingsupplyofhotmetal-risersControlsolidshrinkagebybuildingpatternsslightlyoversizedGrayIronGrayIronGraphiteinflakeform（ASTMA247TypeVII）inamatrixofpearliteFerritenearfinegraphiteflakesGraphiteandaustenitegrowsimultaneouslybyeutect