Metal-casting-铸造说课材料.ppt

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1、1.Metalcasting1.1Conceptofcasting1.2Castingprocess1.3Fluidflow1.4Castingdefects1.5Sandcasting1.6Investmentcasting1.7FoundryandautomationPleaserefertochapters10and11Metalcasting--keywordsCastingMoldGrainFluiditySandcasting/diecastingInvestmentcastingFoundryPat

2、tern/core/porosity/shrinkage1.1ConceptofcastingAdvantages:ComplexshapeswithinternalcavitiesorhollowsectionsVerylargepartsAlmostallmetals,suitableforworkpiecematerialsdifficulttoprocessbyothermeansCompetitivewithotherprocesses1.1ConceptofcastingApplications:Ma

3、nypartsandcomponents,forexamples…1.1ConceptofcastingTrends:MechanizationandautomationofthecastingprocessIncreasingdemandforhigh-qualitycastingswithclosedimensionaltolerancesandnodefects1.2CastingprocessCastingprocess:Pouringmoltenmetalintoamoldpatternedaftert

4、heparttobemanufactured;Allowingittocool;Removingthemetalfromthemold.1.2CastingprocessSolidificationsofmetals:PuremetalsAlloys1.2CastingprocessInfluenceofgrainsizeoncastingproperties:Strengthductilitymicro-porositytendencyforthecastingtocrack.1.3FluidflowCasti

5、ngsystem1.3FluidflowFluidity:thecapabilityofthemoltenmetaltofillmoldcavities.Influencefactorsoffluidity（1）Characteristicsofthemoltenmetal（2）Castingparameters－page249fordetailCastability:theeasewithametalcanbecasttoobtainapartwithgoodquality.Testmethodforcasta

6、bility：1.4CastingdefectsMaininfluencefactors:Materials,partdesign,processingtechniquesSevencategories:（1）metallicprojections（2）cavities--porosity（3）discontinuities(4)defectivesurface(5)Incompletecasting(6)Incorrectdimensionorshape(7)Inclusions1.4Castingdefect

7、sSeeFig.10.111.4CastingdefectsPorosity:maybecausedbyshrinkageorgasesorboth.Methodstoreduceoreliminateporosity—avoidcavitiesbyshrinkage(1)Adequateliquidmetal(2)Internalorexternalchills1.4Castingdefects－－－－－－－－－－－－－－－－Readingprogram:P.256,example.1.5Sandcasting

8、Advantagesandlimitations:--SeeTable11.1,(P.8);Table11.2,(P.9)Processofsandcasting:(1)Placeapatternhavingtheshapeofthedesiredcastinginsandtomakeanimprint;(2)Incorporatingagatingsystem(3)Fi