Cold And Hot Forging: Fundamentals And Applications

334 Pages·2004·9.46 MB·English

by  Taylan Altan

© 2005 ASM International. All Rights Reserved. www.asminternational.org
Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Cold and Hot Forging
Fundamentals and Applications
Edited by
Taylan Altan, ERC/NSM, Ohio State University
Gracious Ngaile, North Carolina State University
Gangshu Shen, Ladish Company, Inc.
MaterialsPark,Ohio44073-0002
www.asminternational.org
© 2005 ASM International. All Rights Reserved. www.asminternational.org
Cold and Hot Forgings: Fundamentals and Applications (#05104G)
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Coldandhotforging:fundamentalsandapplications/editedbyTaylanAltan,Gracious
Ngaile,GangshuShen.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN:0-87170-805-1
1.Forging.I.Altan,Taylan.II.Ngaile,Gracious.III.Shen,Gangshu.
TS225.C632004
671.3(cid:3)32—dc22 2004055439
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ASMInternational(cid:2)
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Contents
Preface ..............................................................................................viii
Chapter1 MetalFormingProcessesinManufacturing...........................1
1.1 ClassificationofManufacturingProcesses .......................................1
1.2 CharacteristicsofManufacturingProcesses ......................................2
1.3 MetalFormingProcessesinManufacturing......................................4
Chapter2 ForgingProcesses:VariablesandDescriptions .......................7
2.1 Introduction ...............................................................................7
2.2 ForgingOperationasaSystem ......................................................7
2.3 TypesofForgingProcesses ...........................................................9
Chapter3 PlasticDeformation:StrainandStrainRate ........................17
3.1 Introduction .............................................................................17
3.2 StressTensor ............................................................................17
3.3 PropertiesoftheStressTensor .....................................................18
3.4 PlaneStressorBiaxialStressCondition ........................................19
3.5 LocalDeformationsandtheVelocityField ....................................20
3.6 Strains .....................................................................................20
3.7 VelocitiesandStrainRates ..........................................................21
3.8 HomogeneousDeformation .........................................................21
3.9 Plastic(True)StrainandEngineeringStrain ...................................23
Chapter4 FlowStressandForgeability ..............................................25
4.1 Introduction .............................................................................25
4.2 TensileTest ..............................................................................27
4.3 CompressionTest ......................................................................29
4.4 RingTest .................................................................................35
4.5 TorsionTest .............................................................................36
4.6 RepresentationofFlowStressData ..............................................36
Appendices(CD-ROMonly)
4.1 DeterminationofFlowStressbyCompressionTestatRoom
Temperature
4.2 DeterminationofFlowStressatHighTemperature
4.3 ForgeabilityandDamageFactorinColdForging
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
iv/ColdandHotForging:FundamentalsandApplications
Chapter5 PlasticDeformation:ComplexStateofStressand
FlowRules .......................................................................51
5.1 StateofStress...........................................................................51
5.2 YieldCriteria............................................................................52
5.3 FlowRules ..............................................................................55
5.4 PowerandEnergyofDeformation ...............................................56
5.5 EffectiveStrainandEffectiveStrainRate ......................................57
Chapter6 TemperaturesandHeatTransfer ........................................59
6.1 Introduction .............................................................................59
6.2 HeatGenerationandHeatTransferinMetalFormingProcesses ........59
6.3 TemperaturesinForgingOperations .............................................60
6.4 MeasurementofTemperaturesattheDie/MaterialInterface ..............60
6.5 MeasurementofInterfaceHeatTransferCoefficient ........................62
6.6 InfluenceofPressSpeedandContactTimeonHeatTransfer ............64
Appendices(CD-ROMonly)
6.1 UpsetForgingofCylinders
Chapter7 FrictionandLubrication ...................................................67
7.1 Introduction .............................................................................67
7.2 LubricationMechanismsinMetalForming ....................................68
7.3 FrictionLawsandTheirValidityinForging ...................................69
7.4 ParametersInfluencingFrictionandLubrication .............................69
7.5 CharacteristicsofLubricantsUsed ...............................................70
7.6 LubricationSystemsforColdForging ..........................................70
7.7 LubricationSystemsforWarmandHotForging .............................73
7.8 MethodsforEvaluationofLubricants ...........................................74
Appendices(CD-ROMonly)
7.1 RingCompressionTest
7.2 DoubleCupExtrusionTest
Chapter8 InverseAnalysisforSimultaneousDeterminationof
FlowStressandFriction ....................................................83
8.1 Introduction .............................................................................83
8.2 InverseAnalysisinMetalForming ...............................................83
8.3 FlowStressDeterminationinForgingbyInverseAnalysis ...............85
8.4 InverseAnalysisforSimultaneousDeterminationofFlowStress
andFriction..............................................................................86
8.5 ExampleofInverseAnalysis .......................................................86
Chapter9 MethodsofAnalysisforForgingOperations ........................91
9.1 Introduction .............................................................................91
9.2 SlabMethodofAnalysis ............................................................93
9.3 UpperBoundMethodandItsApplicationtoAxisymmetric
Upsetting .................................................................................97
9.4 FiniteElementMethodinMetalForming ......................................98
Chapter10 PrinciplesofForgingMachines .......................................107
10.1 Introduction ...........................................................................107
10.2 InteractionbetweenProcessRequirementsandForming
Machines ..............................................................................107
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Contents/v
10.3 LoadandEnergyRequirementsinForming.................................108
10.4 ClassificationandCharacteristicsofFormingMachines .................110
10.5 CharacteristicDataforLoadandEnergy.....................................111
10.6 Time-DependentCharacteristicData ..........................................112
10.7 CharacteristicDataforAccuracy ...............................................112
Chapter11 PressesandHammersforColdandHotForging ...............115
11.1 Introduction ...........................................................................115
11.2 HydraulicPresses ...................................................................115
11.3 ScrewPresses ........................................................................131
11.4 Hammers ..............................................................................135
Chapter12 SpecialMachinesforForging ..........................................141
12.1 Introduction ...........................................................................141
12.2 TransverseorCross-RollingMachines .......................................142
12.3 ElectricUpsetters ...................................................................142
12.4 Ring-RollingMills ..................................................................143
12.5 HorizontalForgingMachinesorUpsetters ..................................144
12.6 RotaryorOrbitalForgingMachines ...........................................145
12.7 RadialForgingMachines .........................................................145
Chapter13 BilletSeparationandShearing ........................................151
13.1 Introduction ...........................................................................151
13.2 BilletandShearedSurfaceQuality ............................................151
13.3 ShearingForce,Work,andPower ..............................................154
13.4 ShearingEquipment ................................................................154
Chapter14 ProcessDesigninImpressionDieForging.........................159
14.1 Introduction ...........................................................................159
14.2 ForgingProcessVariables ........................................................160
14.3 ShapeComplexityinForging ...................................................164
14.4 DesignofFinisherDies ...........................................................165
14.5 PredictionofForgingStressesandLoads ....................................169
14.6 DesignofBlocker(Preform)Dies .............................................171
AppendixA ExampleofLoadforForgingofaConnectingRod ...............177
A.1 Introduction ............................................................................177
A.2 EstimationoftheFlowStress ....................................................178
A.3 EstimationoftheFrictionFactor ................................................181
A.4 EstimationoftheForgingLoad ..................................................181
A.5 ComparisonofPredictionswithDatafromActualForgingTrials .....181
Appendices(CD-ROMonly)
14.1 PreformDesigninClosedDieForging
14.2 FlashDesigninClosedDieForging
Chapter15 ASimplifiedMethodtoEstimateForgingLoadin
Impression-DieForging ..................................................185
15.1 Introduction ...........................................................................185
15.2 EffectofProcessParametersonForgingLoad .............................185
15.3 MethodsforLoadEstimation ...................................................186
15.4 SimplifiedMethodforLoadEstimation ......................................190
15.5 ExampleofLoadEstimation ....................................................191
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
vi/ColdandHotForging:FundamentalsandApplications
Appendices(CD-ROMonly)
15.1 ForgePAL: A Computer Program for Estimating Forces in
HotForgingwithFlash
Chapter16 ProcessModelinginImpression-DieForgingUsing
Finite-ElementAnalysis ..................................................193
16.1 Introduction ...........................................................................193
16.2 InformationFlowinProcessModeling .......................................194
16.3 ProcessModelingInput ...........................................................194
16.4 CharacteristicsoftheSimulationCode .......................................196
16.5 ProcessModelingOutput .........................................................197
16.6 ExamplesofModelingApplications ..........................................200
Chapter17 ColdandWarmForging .................................................211
17.1 Introduction ...........................................................................211
17.2 ColdForgingasaSystem ........................................................213
17.3 MaterialsforColdForging .......................................................213
17.4 BilletPreparationandLubricationinColdForgingofSteel
andAluminum .......................................................................214
17.5 Upsetting ..............................................................................215
17.6 LoadEstimationforFlashlessClosed-DieUpsetting .....................216
17.7 Extrusion ..............................................................................218
17.8 EstimationofFrictionandFlowStress .......................................221
17.9 PredictionofExtrusionLoadsfromSelectedFormulas..................222
17.10 PredictionofExtrusionLoadsfromModelTest .........................224
17.11 ToolingforColdForging .......................................................225
17.12 PunchDesignforColdForging ...............................................227
17.13 DieDesignandShrinkFit ......................................................228
17.14 ProcessSequenceDesign .......................................................229
17.15 ParametersAffectingToolLife ................................................230
17.16 WarmForging ......................................................................233
Appendices(CD-ROMonly)
17.1 ExamplesofForgingSequences
17.2 ForwardRodExtrusion
17.3 BackwardRodExtrusion
Chapter18 ProcessModelinginColdForgingUsingFinite-Element
Analysis ........................................................................237
18.1 Introduction ...........................................................................237
18.2 ProcessModelingInput ...........................................................237
18.3 ProcessModelingOutput .........................................................239
18.4 ProcessModelingExamples .....................................................239
Chapter19 MicrostructureModelinginSuperalloyForging ................247
19.1 Introduction ...........................................................................247
19.2 ExperimentsforMicrostructureModelDevelopment ....................247
19.3 MicrostructureModelFormulation ............................................248
19.4 PredictionofMicrostructureinSuperalloyForging .......................254
19.5 NomenclatureofMicrostructureModel ......................................254
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Contents/vii
Chapter20 IsothermalandHotDieForging ......................................257
20.1 Introduction ...........................................................................257
20.2 IsothermalForging..................................................................257
20.3 Hot-DieForging .....................................................................258
20.4 BenefitsofIsothermalandHot-DieForging ................................258
20.5 High-TemperatureMaterialsforIsothermalandHot-DieForging ....259
20.6 EquipmentandTooling ...........................................................263
20.7 PostforgingHeatTreatment ......................................................269
20.8 ProductionofIsothermal/Hot-DieForging ..................................271
20.9 EconomicBenefitsofIsothermalandHot-DieForging ..................272
20.10 Summary ..............................................................................273
Chapter21 DieMaterialsandDieManufacturing ..............................277
21.1 Introduction ...........................................................................277
21.2 DieandToolMaterialsForHotForging .....................................277
21.3 HeatTreatment ......................................................................285
21.4 DieandToolMaterialsforColdForging ....................................285
21.5 DieManufacture ....................................................................289
21.6 SurfaceTreatments .................................................................292
Chapter22 DieFailuresinColdandHotForging ..............................295
22.1 Introduction ...........................................................................295
22.2 ClassificationofDieFailures ....................................................295
22.3 FractureMechanisms ..............................................................296
22.4 WearMechanisms...................................................................296
22.5 AnalyticalWearModels...........................................................297
22.6 ParametersInfluencingDieFailure ............................................297
22.7 PredictionofDieFatigueFractureandEnhancementofDieLife
inColdForgingUsingFinite-ElementModeling(FEM) ................307
22.8 PredictionofDieWearandEnhancementofDieLifeUsingFEM ..311
Chapter23 Near-NetShapeForgingandNewDevelopments ...............319
23.1 Introduction ...........................................................................319
23.2 TolerancesinPrecisionForging ................................................319
23.3 AdvancesinToolDesign .........................................................323
23.4 AdvancesinForgingMachines .................................................326
23.5 InnovativeForgingProcesses ....................................................328
23.6 FutureofForgingTechnologyintheGlobalMarketplace ..............331
Index ................................................................................................337
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Preface
Amongallmanufacturingprocesses,forgingtechnologyhasaspecialplacebecause
it helps to produce parts of superior mechanical properties with minimum waste of
material.Inforging,thestartingmaterialhasarelativelysimplegeometry;thismaterial
isplasticallydeformedinoneormoreoperationsintoaproductofrelativelycomplex
configuration. Forging to net or to net shape dimensions drastically reduces metalre-
movalrequirements,resultinginsignificantmaterialandenergysavings.Forgingusu-
ally requires relatively expensivetooling. Thus, theprocessiseconomicallyattractive
whenalargenumberofpartsmustbeproducedand/orwhenthemechanicalproperties
requiredinthefinishedproductcanbeobtainedonlybyaforgingprocess.
Theever-increasingcostsofmaterial,energy,and,especially,manpowerrequirethat
forging processes and tooling be designed and developed with minimum amount of
trial and error with shortest possible lead times. Therefore,toremaincompetitive,the
cost-effective application of computer-aided techniques, i.e., CAD, CAM, CAE, and,
especially,finiteelementanalysis(FEA)-basedcomputersimulationisanabsolutene-
cessity. The practical use of these techniques requires a thorough knowledge of the
principalvariablesoftheforgingprocessandtheirinteractions.Thesevariablesinclude:
a)theflowbehavioroftheforgedmaterialunderprocessingconditions,b)diegeometry
andmaterials,c)frictionandlubrication,d)themechanicsofdeformation,i.e.,strains
andstresses,e)thecharacteristicsoftheforgingequipment,f)thegeometry,tolerances,
surfacefinishandmechanicalpropertiesoftheforging,andg)theeffectsoftheprocess
ontheenvironment.
There are many excellent handbooks and technical papers on the technology ofthe
forging. These principles are reviewed briefly in this book, but major emphasis is on
the latest developments in the design of forging operations and dies. Thus, process
modeling using FEA has been discussed in all appropriate chapters. The subject is
introduced in Chapter 1 with a discussion of the position of metal forming processes
inmanufacturing.Chapter2considersforgingprocessasasystemconsistingofseveral
variablesthatinteractwithoneanother.Thischapteralsoincludesanoverallreviewof
the forging operations. Thefundamentalsof plasticdeformation,i.e.,metalflow,flow
stress of materials, testing methods to determine materials properties, and flow rules
arediscussed in Chapters3, 4, and 5. Chapters6 and 8 coverthesignificantvariables
of the forging process such as friction, lubrication, and temperatures. Chapter 9 is
devotedtoapproximatemethodsforanalyzingsimpleforgingoperations.Chapters10
through13discussforgingmachines,includingmachinesforshearingandpre-forming
ormaterialsdistribution.Processanddiedesign,methodsforestimatingforgingloads,
and the application of FEA-based process modeling in hot forging are discussed in
Chapters14,15,and16.
Chapters17and18covercoldandwarmforging,includingtheapplicationofFEA
simulationintheseprocesses.Microstructuremodeling,usingforgingofhightempera-
ture alloys as example, is covered in Chapter 19, while Chapter 20 is devoted to iso-
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Cold and Hot Forgings: Fundamentals and Applications (#05104G)
Preface/ix
thermalandhotdieforgingofaerospacealloys.Diematerials,diemanufacturing,and
diewearinhotandcoldforgingarediscussedinChapters21and22.
Finally,Chapter23reviewsthenear-netshapeforgingtechnology,includingenclosed
die forging, multiple-action tooling, and the most recent developments in forging
presses.Thischapteralsodiscussesbrieflythefutureofforgingtechnologyintheglobal
economy,theimportanceofinformationtechnologyintheforgeshop,and,finally,the
need to continuously acquire knowledge on new methods and techniques to remain
competitive.
Several chapters of the book (Chapters 4, 6, 7, 14, 15 and 17) contain appendixes
that consist of presentation slides and computer animations.Theanimationsrepresent
theresultsofFEAsimulationsforvariousforgingoperations.TheyaregiveninaCD
that is included with this book. The reader is encouraged to use the CD and these
appendixes in order to understand better and easier some of the fundamental issues
discussedincorrespondingchapters.
The preparation of this book has been supported partially by the Jacob Wallenberg
Foundation Prize, awarded to Dr. Taylan Altan by the Royal Swedish Academy of
Engineering Sciences. The staff and the students of the Engineering Research Center
for Net Shape Manufacturing (ERC/NSM) of The Ohio State University contributed
significantly to the preparation of the book. Specifically, Mr. Pinak Barve, Graduate
ResearchAssociate,providedvaluableassistanceinpreparingthetextandthefigures.
Considerableinformationhasbeensuppliedbyalargenumberofcompaniesthatsup-
porttheforgingresearchanddevelopmentattheERC/NSM.Onbehalfoftheauthors
and the editors, I would like to thank all who made our work so much easier.Finally,
Iwouldliketothankmywife,SusanAltan,whohasofferedmeenormoussupportand
encouragementthroughoutthepreparationofthisbook.
TaylanAltan
December2004
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