METAL FORMING PROCESSES

Introduction about metal forming process

1. METAL FORMING PROCESSES
Hotworkingandcoldworkingofmetals–Forgingprocesses–Open,
impressionandcloseddieforging–Characteristicsoftheprocess–Typesof
ForgingMachines–Typicalforgingoperations–Rollingofmetals–Types
ofRollingmills-Flatstriprolling–Shaperollingoperations–Defectsin
rolledparts-Principleofrodandwiredrawing-Tubedrawing––Principles
ofExtrusion–TypesofExtrusion–HotandColdextrusion–Equipments
used.

2. HOTWORKINGOFMETALS
Mechanicalworkingofametalabovetherecrystallizationtemperature
butbelowthemeltingpoint.
Plasticdeformationofmetalsandalloysundertheconditionof
temperatureandstrainrate.
Recrystallizationtemperatureis30to40%ofmeltingtemperature.
Inthisprocess,MetalisheatedabovetheRTwith0.7to0.9timesofthe
meltingtemperature.
TYPESOFHOTWORKINGPROCESS
-Hotforging
-HotRolling
-HotExtrusions
-Drawing
-Swaging
-HotSpinning

3. COLDWORKINGOFMETALS
Plasticdeformationofametaltotherequiredshapebeingperformed
belowtherecrystallizationtemperature.
Processwillworkunderroomtemperature.
RT–“Minimumtemperatureatwhichthecompleterecrystallizationof
ametaltakesplacewithinaspecifiedtime”
TYPESOFCOLDWORKINGPROCESS
-Drawing
-Squeezing
-Bending

4. 1.0Drawing
-BlankDrawing
Cuttingaflatshapefromthemetal.
-TubeDrawing
Tubepiercingisnothingbuttubedrawing
-Embossing
Processofmakingraisedorprojecteddesign
onthesurfaceofthemetal.
-WireDrawing
Diameterlessthan16mmhasdrawninthe
formofwirecoil.
-MetalSpinning

5. 2.0Squeezing
-Coining
-Sizing
Sizethemetaltorequiredshapes
-Swaging
Itisusedforproducingrounded
componentsthroughradialimpactforces
byreciprocatingdies.
-Knurling
Therollsarepressedradiallyagainstthe
rotatingworkpiece,tomakegriponthe
handles.

6. 3.0Bending
BendintoDesiredshapelikerods,wires,bars
-PlateBending
LargePlatesarebenttoshapes
-RollForming
-Itcarriesthreerolls,Twoarefixedandthethirdoneisadjustable.
Diameterofallrollsaresame.
-AngleBending
Angles,Circles,Ovals

7. FORGING PROCESSES
Thedesiredshapeisobtainedbytheapplicationofacompressiveforce.
Types
1.0SmithorOpendieForging
Theforgingisdoneinaheatedworkatthepropertemperatureby
placingonflatsurfaceanvilthroughhammeringthemetalpiece.
a)HandForging
b)PowerForging

8. 2.0 Closeddie Forging
a) Drop Forging

9. b) Press Forging
Applications

10. c) UpsetForging
3.0 Roll Forging

11. TYPES OF FORGING MACHINES
1.0AirandSteamHammer
a)AirHammer
Itusingairorsteam.
-Singleactinghammer–Airpressureisusedtolifttheramonly.
-Doubleactinghammer–Airpressureisusedtolifttheramand
Impacttheworkpiece.

12. 1.0AirandSteamHammer
b)SteamHammer
Itusingairorsteam.
-Singleactinghammer–Airpressureisusedforlightwork.
-Doubleactinghammer–Airpressureisusedforheavywork.

13. 2.0MechanicalHammer
a)HelveHammer
b) Trip Hammer
The reciprocating ram is the main part and it is toggle. The stroke length
various from 175 to 400blows/min.

14. 2.0MechanicalHammer
c)LevelSpringHammer
d) Pneumatic Hammer
An elastic rod is used to operate the ram. The stroke length various from 40
to 200blows/min.

15. TYPES OF FORGING OPERATIONS
1.0Upsetting
Themetalisheatedatoneendandtheforceisappliedontheother
endbyusinghammer.Thecrosssectionalareawillincreaseandlengthwill
decrease.

16. TYPES OF FORGING OPERATIONS
3.0Punching
Inthisprocess,makingofaholeina
givenjob.
4.0Bending
Inthisprocess,shapeslikeangles,
ovalsandcirclecanbemade.
2.0DrawingDown
Inthisprocess,thecross
sectionalareawilldecreaseandlengthwill
increase.

17. TYPES OF FORGING OPERATIONS
6.0ForgeWelding
Joiningtheworkpiecesbyforging
operation.
7.0Piercing
Makingablindorthroughholeswiththehelpofapunchinthemetal.
5.0Cutting
Removalofexcessmetalfromthework.

18. TYPES OF FORGING OPERATIONS
8.0Swaging
Reducingorchangingthecrosssectionalareaofthemetal.
9.0Flattering
Usedtoflatthestockandthatthestockisfittedproperlyinthecloseddie.
10.0Fullering
Reducingthestockandincreasingthelengthoftheworkpiecebyapplying
pressure.

19. ROLLING OF METALS
Deformingthemetalintosemifinishedorfinishedconditionbypassingthemetal
pieceinbetweenthetworollers.

20. FLAT STRIP ROLLING

21. FLAT STRIP ROLLING

22. Problem 1:
 A 300 mm wide strip 25 mm thick is fed
through a rolling mill with two powered rolls each
od radius = 250mm. The work thickness is to be
reduced to 22 mm in one pass at a roll speed of 50
rev / min. The work material has a flow curve
defined by K = 275MPa and n = 0.15 and the
coefficient of friction between rolls and work is
assumed to be 0.12. Determine if the friction is
sufficient to permit the rolling operation to be
accomplished. If so, calculate the roll force,
torque and horsepower.

26. Classification of Rolling Based on Number of Rolls
1.0Twohighrollingmill 2.0Threehighrollingmill

27. Classification of Rolling Based on Number of Rolls
3.0Fourhighrollingmill 4.0Multiplerollmills

28. Classification of Rolling Based on Number of Rolls
5.0Universalrollingmill

29. SHAPE ROLLING OPERATIONS
Straightandlongstructuralshapes,solidbars,I–Beams,Channels,Railroadrails.

30. SHAPE ROLLING OPERATIONS
1.0Ringrolling
Athickringisexpandedintoalargediameterringwithareducedcross
section.Theringisplacedinbetweentworollsandoneoftherollisdriven,ring
thicknessisreduced.
Advantages:
-Close tolerances
-Material Saving
-Short production times

31. SHAPE ROLLING OPERATIONS
2.0Threadrolling
Straightortaperedthreadsareformed.Threadsareformedontherod,
witheachstrokeofapairofflatreciprocatingdies
Advantages:
-Surface finish
good
-Long life
-Thread strength
is good

32. DEFECTS IN ROLLED PARTS
1.0SurfaceDefects
Itincludesscale,rust,cracksandpitsduetoimpuritiesandinclusion
2.0InternalStructuralDefects
Strainonthematerialshouldadjust.

33. DEFECTS IN ROLLED PARTS
3.0OtherDefects
a)Homogeneousdeformationofelementacrossthewidth
Duetodecreaseinthicknessfortheelementsnearthecentrewillbemainlyconverted
intoincreaseinlengthandneartheedgethedecreaseinthicknessisconvertedinto
lateralspread.
b)Homogeneousdeformationinthethicknesssection
Duetoreductioninheightisconvertedintoincreaseinlengthandthethicknessofthe
sheetdoesnotundergothesamelateraldeformation.
c)Folds
Itiscreatedduringplaterollingifthereductionperpassisverysmall.
d)Lamination
Duetoincompleteweldingofpipeandblowholesduringtherollingprocesstheinternal
defectssuchasfissuresarecreated.

34. CLASSIFICATION OF DRAWING
1.0 WIRE DRAWING
Diameterlessthan16mmhasdrawnintheformofwirecoil.

35. CLASSIFICATION OF DRAWING
2.0 ROD DRAWING
Placingthehotdrawnbarthroughadieofwhichtheboresizeconformstothe
finishedsizeofproduct.

36. CLASSIFICATION OF DRAWING
3.0 TUBE DRAWING
CylindersandTubesaremadebyextrusionprocess.
a)TubeSinking b)Tubemandrel

37. CLASSIFICATION OF DRAWING
3.0 TUBE DRAWING
c)TubePlug

38. CLASSIFICATION OF DRAWING
4.0 DEEP DRAWING
Todrawthecupshapedpartsfromthemetals.

39. Bull Block

40. Draw Bench

41. EXTRUSION
Heatedmetaliscompressed
andforcedthroughasuitable
shapeddie–HotExtrusion.
Coldextrusionisnonheated
metalbutforceisrequired
andusedforcommercial
metals.

42. TYPES OF EXTRUSION
1.0 HOT EXTRUSION
a) Forward or direct extrusion.

43. TYPES OF EXTRUSION
1.0 HOT EXTRUSION
b) Backward or Indirect extrusion.

44. TYPES OF EXTRUSION
2.0 COLD OR IMPACT EXTRUSION