各种锻造成型设备英文解释文档格式.docx
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各种锻造成型设备英文解释文档格式.docx
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oPressForging
oDieForging
∙Forgingequipment
oSmithForgingHammer
oBoardDropHammer
oForgingPress
oMechanicalForgingPress
oHydraulicForgingPress
∙HeatTreatments
oPreheating
oAnnealing
oNormalizing
oHardening
∙LISTSOFFORGINGMANUFACTURERS
oForgingandFormingResources
oForgingIndustryAssociation
oForgingEquipment–JohnsonForgingEquipmentCompany
oForgingEquipment–SIFCOIndurtries,Inc.-ForgeGroup
oForgingEquipment–DeltaforgingServices,Inc
Process:
Forgingisametalformingprocessusedtoproducelargequantitiesofidenticalparts,asinthemanufactureofautomobiles,andtoimprovethemechanicalpropertiesofthemetalbeingforged,asinaerospacepartsormilitaryequipment.Thedesignofforgedpartsislimitedwhenundercutsorcoredsectionsarerequired.Allcavitiesmustbecomparativelystraightandlargestatthemouth,sothattheforgingdiemaybewithdrawn.Theproductsofforgingmaybetinyormassiveandcanbemadeofsteel(automobileaxles),brass(watervalves),tungsten(rocketnozzles),aluminum(aircraftstructuralmembers),oranyothermetal.MorethantwothirdsofforgingintheUnitedStatesisconcentratedinfourgeneralareas:
30percentintheaerospaceindustry,20percentinautomotiveandtruckmanufacture,10percentinoff-highwayvehicles,and10percentinmilitaryequipment.Thisprocessisalsousedforcoining,butwithslowcontinuouspushes.
TheforgingmetalformingprocesshasbeenpracticedsincetheBronzeAge.Hammeringmetalbyhandcanbedatedbackover4000yearsago.Thepurpose,asitstillistoday,wastochangetheshapeand/orpropertiesofmetalintousefultools.Steelwashammeredintoshapeandusedmostlyforcarpentryandfarmingtools.Anaxmadeeasyworkofcuttingdowntreesandmetalknivesweremuchmoreefficientthanstonecuttingtools.Huntersusedmetal-pointedspearsandarrowstocatchprey.Blacksmithsusedaforgeandanviltocreatemanyusefulinstrumentssuchashorseshoes,nails,wagontires,andchains.
Militariesusedforgedweaponstoequiptheirarmies,resultinginmanyterritoriesbeingwonandlostwiththeuseandstrengthoftheseweapons.
Today,forgingisusedtocreatevariousandsundrythings.Theoperationrequiresnocuttingorshearing,andismerelyareshapingoperationthatdoesnotchangethevolumeofthematerial.
Forging:
Forgingchangesthesizeandshape,butnotthevolume,ofapart.Thechangeismadebyforceappliedtothematerialsothatitstretchesbeyondtheyieldpoint.Theforcemustbestrongenoughtomakethematerialdeform.Itmustnotbesostrong,however,thatitdestroysthematerial.Theyieldpointisreachedwhenthematerialwillreformintoanewshape.Thepointatwhichthematerialwouldbedestroyediscalledthefracturepoint.
Inforging,ablockofmetalisdeformedunderimpactorpressuretoformthedesiredshape.Coldforging,inwhichthemetalisnotheated,isgenerallylimitedtorelativelysoftmetals.Mostmetalsarehotforged;
forexample,steelisforgedattemperaturesbetween2,100oFand2,300oF(1,150oCto1,260oC).Thesetemperaturescausedeformation,inwhichthegrainsofthemetalelongateandassumeafibrousstructureofincreasedstrengthalongthedirectionofflow.(SeeFigure)
Figure-Flowlinesinaforgedpart
Normallythisresultsinmetallurgicalsoundnessandimprovedmechanicalproperties.Strength,toughness,andgeneraldurabilitydependuponthewaythegrainisplaced.Forgingsaresomewhatstrongerandmoreductilealongthegrainstructurethanacrossit.Thefeatureofgreatestimportanceisthatalongthegrainstructurethereisagreaterabilitytoresistshock,wear,andimpactthanacrossthegrain.Materialpropertiesalsodependontheheat-treatingprocessafterforging.Slowcoolinginairmaynormalizeworkpieces,ortheycanbequenchedinoilandthentemperedorreheatedtoachievethedesiredmechanicalpropertiesandtorelieveanyinternalstresses.Goodforgingpracticemakesitpossibletocontroltheflowpatternresultinginmaximumstrengthofthematerialandtheleastchancesoffatiguefailure.Thesecharacteristicsofforging,aswellasfewerflawsandhiddendefects,makeitmoredesirablethansomeotheroperations(i.e.casting)forproductsthatwillundergohighstresses.
Inforging,thedimensionaltolerancesthatcanbeheldvarybasedonthesizeoftheworkpiece.Theprocessiscapableofproducingshapesof0.5to>
50.0cminthicknessand10to<
100cmindiameter.Thetolerancesvaryfrom1/32in.forsmallpartsto¼
in.forlargeforgings.Tolerancesof0.010in.havebeenheldinsomeprecisionforgings,butthecostassociatedwithsuchprecisionisonlyjustifiedinexceptionalcases,suchassomeaircraftwork.
Typesofforging:
Forgingisdividedintothreemainmethods:
hammer,press,androlledtypes.
(1)
HammerForging(FlatDie):
Preferredmethodforindividualforgings.Theshapingofametal,orothermaterial,byaninstantaneousapplicationofpressuretoarelativelysmallarea.Ahammerorram,deliveringintermittentblowstothesectiontobeforged,appliesthispressure.Thehammerisdroppedfromitsmaximumheight,usuallyraisedbysteamorairpressure.Hammerforgingcanproduceawidevarietyofshapesandsizesand,ifsufficientlyreduced,cancreateahighdegreeofgrainrefinementatthesametime.Thedisadvantagetothisprocessisthatfinishmachiningisoftenrequired,asclosedimensionaltolerancescannotbeobtained.
(2)
PressForging:
Thisprocessissimilartokneading,whereaslowcontinuouspressureisappliedtotheareatobeforged.Thepressurewillextenddeepintothematerialandcanbecompletedeithercoldorhot.Acoldpressforgingisusedonathin,annealedmaterial,andahotpressforgingisdoneonlargeworksuchasarmorplating,locomotivesandheavymachinery.
PressForgingismoreeconomicalthanhammerforging(exceptwhendealingwithlowproductionnumbers),andclosertolerancescanbeobtained.Agreaterproportionoftheworkdoneistransmittedtotheworkpiece,differingfromthatofthehammerforgingoperation,wheremuchoftheworkisabsorbedbythemachineandfoundation.Thismethodcanalsobeusedtoproducelargerforgings,asthereisnolimitationinthesizeofthemachine.
(3)
DieForging:
Openandcloseddieoperationscanbeusedinforging.Inopen-dieforgingthediesareeitherflatorrounded.Largeforgingscanbeformedbysuccessiveapplicationsofforceondifferentpartsofthematerial.Hydraulicpressesandforgingmachinesarebothemployedincloseddieforging.Inclosed-dieforgingthemetalistrappedinrecessedimpressions,whicharemachinedintothetopandbottomdies.Asthediespresstogether,thematerialisforcedtofilltheimpressions.Flash,orexcessmetal,issqueezedoutbetweenthedies.Closed-dieforgingcanproducepartswithmorecomplexshapesthanopen-dieforging.
Dieforgingisthebestmethod,asfarastolerancesthatcanbemet,andalsoresultsinafinishedpartthatiscompletelyfilledoutandisproducedwiththeleastamountofflashing.Thefinalshapeandtheimprovementinmetallurgicalpropertiesaredependentontheskilloftheoperator.Closerdimensionaltolerancescanbeheldwithcloseddieforgingsthanwithopendieforgingsandtheoperatorrequireslessskill.
ForgingEquipment:
Thetypeofmachinerytobeuseddependsontheshape,size,material,andnumberofpiecestobemade.Forginghammersapplyforcebytheimpactofalargeram.Thismaybeadrophammer,orweightfallingundertheforceofgravity,oritmaybeapowerhammer,drivenbysteamorcompressedair.Twotypesofpowerhammersare:
thesmithforginghammerandthedrophammer.Thelargesthammerscanprovideatotalforceashighas80,000pounds.
SmithForgingHammerandBoardDropHammer
∙∙
SmithForgingHammerHeavyworkpiecescouldbeprocessedusingasmith-forginghammer,andsmallerforgingsaredieformedindrophammers.
Smithforginghammersaretypicallysteamorair-operated,consistingofapoweractuatedramsupportedbyaheavycastironframe.Thefinalproductisaresultoftherambeingpoweredintothediescontainingtheworkpiece.
BoardDropHammerAdrophammerdiffersinthattheanvilisanintegratedpartofthehammerbase.Itisnecessaryforthealignmentbetweentheforgingdieelementsused.Thismethodisadvantageousinthatthephysicalpropertiesofthemetalareimprovedbytheseveremechanicalworking,theoperationisrapid,manycomplicatedpartscanbeforgedtoshape,aminimumamountofmachiningisnecessary,andinternaldefectsareeliminated.
Thedisadvantagesarethecostofmachineryanddies,whichdemandsahighquantityofpartstobemanufacturedinorderfortheprocesstobecosteffective.
ForgingPressAforgingpressconsistsofahydraulicpress,whichexertsaforcecapableofpressingsteelorametalalloyintotheshapeoftheforgingdie.Thesemachinescanbepositionedhorizontallyorvertically.Thismethodcanbeusedtoformcarwheels,gears,bushings,andothersuchparts.
MechanicalForgingPress
Mechanicalpresseshaveamotor-drivenflywheelthatstoresenergytodrivearam--muchlighterthanahammer--throughacrankorothermechanicaldevice.Theraminapressmovesmoreslowlythanahammerandsqueezestheworkpiece.Thelargestmechanicalpresseshaveatotalforceof12,000tonsandcannotforgeaslargeorcomplicatedpartsasthelargerhammers.
Hydrauli
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