铁合金铸造(铸铁铸造类英语培训材料)真的很好PPT资料.ppt
《铁合金铸造(铸铁铸造类英语培训材料)真的很好PPT资料.ppt》由会员分享,可在线阅读,更多相关《铁合金铸造(铸铁铸造类英语培训材料)真的很好PPT资料.ppt(54页珍藏版)》请在冰豆网上搜索。
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