材料加工工艺14章

MetalFormingProcessesMetalFormingProcesses(5)(5)„„5.15.1(())„„5.25.2„„5.35.3„„5.45.4„„5.55.5DeepdrawingDeepdrawing5.15.1(())¾¾ƒ¾ƒƒ¾¾ƒ¾ƒ5.25.2σ1σ2σ3ε1ε2ε3σ1σ2σ3ε1ε2ε3σ2σ1ε2ε1σ1σ3σ2ε1ε2ε3σ1σ3ε1ε2ε35.35.311ddDD00mmm=d/Dm=d/D002233K=1/mK=1/m5.35.344mmnn=d=dnn/d/dnn--115566smσQtpdPpπ=dptRdrR’µbσp12)6.11)(2ln1.1('++++=tRtdQrRpdbpsmσµπµσ12)6.11)(2ln1.1('++++=tRtdQrRpdbpsmσµπµσ11KtdPbσπ=22KtdPbσπ=5.45.41.2.3.11:1)2)3)4)22123„„„„11t/Dt/D00„„,,,,„„22m=d/Dm=d/D00„„3)3)..„12312313“”“”455.55.5(())(A)adouble-actingpresswithtworams(B)ainsingle-actingpresswithacushionsysteminthepresstable.(C)Hydrauliccylinderssometimesareinstalledinthefourcornerpointsofthepresstable.1—2—3—4—5—6—1—2—3—4—5—6—1—2—3—4—5—6—7—8—1.1.2.2.3.3.)(1rhdA−=πArdrr224228=−+ππ[()]Adr3242=−π())(48)2(2)2(22rhdrrdrrdD−++−+−=π1.2.„„„„„„„„BulgingdrawingBulgingdrawing5.65.75.75.65.6„„BulgingBulging„„„„„„„„„„„„„„„„„„„„5.75.7PVC——————1—2—3—4—5—1—2—3—4—1—2—3—4—HydroformingHydroformingPi:InternalpressureFa:AxialforceFq:CounterforceRc:CornerradiusRe:Entryradius(1)Dies(2)Countercylinder(3)Axialcylinders(4)Initialtube(5)FinaltubeActiveforcesinahydroformingprocessatypicalpartthatisbeingformedbyhydroformingtechnique.Thetubeispressurizedwhileaxiallyfedtowardstheexpansionzone1.Pre-benttube2.Crushedtube3.HydroformedpartSeveralfactorsplayanimportantroleinmaterialselectionfortubehydroforming.Thesefactorsincludefinalpropertiesofthepartfinalpropertiesofthepart,formingprocessanddeformationcapabilities,availabilityandcost.Inmanycasesthematerialselectionmayincludeatradeoffbetweenvariouscompetingparameters.————Resultscomparedtoconventionalsteelbodystructure:-50%lessweight-45%lessparts(lesstools,lessassembly)-45%lessweldingseams-tightertolerancesVolvoHydroformedStructureconceptinaluminum,(SchulerHydroforming1998)cagecageCarframe,(AUDI,1998)TowerLightTruckChassiswithHydroformedComponents,(SchulerHydroforming,1998)Aluminumrearaxlepart500series,(BMW,1997)lightweight-reducednumbersofparts-reducedinternalpressureloss(duringengineoperationVOLVOhydroformedexhaustcomponents(SchulerHydrofoming,1998)VW2.01-1.6lV-4-cylinders(SchulerHydrofoming,1998)BMWV-4-cylinders(SchulerHydrofoming,1998)12„„„„??„„„„