Hot working and cold working of metals – Forging processes – Open, impression and closed die forging – Types of Forging Machines – Typical forging operations. Rolling of metals– Types of Rolling – Flat strip rolling – shape rolling operations – Defects in rolled parts. Principle of rod and wire drawing – Tube drawing – Principles and types of Extrusion – Hot and Cold extrusion.

1. METAL FORMING PROCESSES
Hot working and cold working of metals – Forging processes – Open,
impression and closed die forging – Types of Forging Machines – Typical
forging operations. Rolling of metals– Types of Rolling – Flat strip
rolling – shape rolling operations – Defects in rolled parts. Principle of rod
and wire drawing – Tube drawing – Principles and types of Extrusion – Hot
and Cold extrusion.

2. HOT WORKING OF METALS
Mechanical working of a metal above the recrystallization temperature
but below the melting point.
Plastic deformation of metals and alloys under the condition of
temperature and strain rate.
Recrystallization temperature is 30 to 40% of melting temperature.
In this process, Metal is heated above the RT with 0.7 to 0.9 times of the
melting temperature.
TYPES OF HOT WORKING PROCESS
-Hot forging
-Hot Rolling
-Hot Extrusions
-Drawing
-Swaging
-Hot Spinning

3. COLD WORKING OF METALS
Plastic deformation of a metal to the required shape being performed
below the recrystallization temperature.
Process will work under room temperature.
RT – “Minimum temperature at which the complete recrystallization of
a metal takes place with in a specified time”
TYPES OF COLD WORKING PROCESS
- Drawing
- Squeezing
- Bending

4. 1.0 Drawing
- Blank Drawing
Cutting a flat shape from the metal.
-Tube Drawing
Tube piercing is nothing but tube drawing
-Embossing
Process of making raised or projected design
on the surface of the metal.
-Wire Drawing
Diameter less than 16mm has drawn in the
form of wire coil.
-Metal Spinning

5. 2.0 Squeezing
- Coining
-Sizing
Size the metal to required shapes
-Swaging
It is used for producing rounded
components through radial impact forces
by reciprocating dies.
-Knurling
The rolls are pressed radially against the
rotating work piece, to make grip on the
handles.

6. 3.0 Bending
Bend into Desired shape like rods, wires, bars
- Plate Bending
Large Plates are bent to shapes
- Roll Forming
-It carries three rolls, Two are fixed and the third one is adjustable.
Diameter of all rolls are same.
- Angle Bending
Angles, Circles, Ovals

7. FORGING PROCESSES
The desired shape is obtained by the application of a compressive force.
Types
1.0 Smith or Open die Forging
The forging is done in a heated work at the proper temperature by
placing on flat surface anvil through hammering the metal piece.
a) Hand Forging
b) Power Forging

8. 2.0 Closed die Forging
a) Drop Forging

9. b) Press Forging
Applications

10. c) Upset Forging
3.0 Roll Forging

11. TYPES OF FORGING MACHINES
1.0 Air and Steam Hammer
a) Air Hammer
It using air or steam.
- Single acting hammer – Air pressure is used to lift the ram only.
- Double acting hammer – Air pressure is used to lift the ram and
Impact the work piece.

12. 1.0 Air and Steam Hammer
b) Steam Hammer
It using air or steam.
- Single acting hammer – Air pressure is used for light work.
- Double acting hammer – Air pressure is used for heavy work.

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

14. 2.0 Mechanical Hammer
c) Level Spring Hammer
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
1.0 Upsetting
The metal is heated at one end and the force is applied on the other
end by using hammer. The cross sectional area will increase and length will
decrease.

16. TYPES OF FORGING OPERATIONS
3.0 Punching
In this process, making of a hole in a
given job.
4.0 Bending
In this process, shapes like angles,
ovals and circle can be made.
2.0 Drawing Down
In this process, the cross
sectional area will decrease and length will
increase.

17. TYPES OF FORGING OPERATIONS
6.0 Forge Welding
Joining the work pieces by forging
operation.
7.0 Piercing
Making a blind or through holes
with the help of a punch in the metal.
5.0 Cutting
Removal of excess metal from the work.

18. TYPES OF FORGING OPERATIONS
8.0 Swaging
Reducing or changing the cross sectional area of the metal.
9.0 Flattering
Used to flat the stock and that the stock is fitted properly in the closed die.
10.0 Fullering
Reducing the stock and increasing the length of the work piece by applying
pressure.

19. ROLLING OF METALS
Deforming the metal into semi finished or finished condition by passing the metal
piece in between the two rollers.

20. FLAT STRIP ROLLING

21. FLAT STRIP ROLLING

22. Classification of Rolling Based on Number of Rolls
1.0 Two high rolling mill 2.0 Three high rolling mill

23. Classification of Rolling Based on Number of Rolls
3.0 Four high rolling mill 4.0 Multiple roll mills

24. Classification of Rolling Based on Number of Rolls
5.0 Universal rolling mill

25. SHAPE ROLLING OPERATIONS
Straight and long structural shapes, solid bars, I –Beams, Channels, Railroad rails.

26. SHAPE ROLLING OPERATIONS
1.0 Ring rolling
A thick ring is expanded into a large diameter ring with a reduced cross
section.
Advantages:
-Close tolerances
-Material Saving
- Short production times

27. SHAPE ROLLING OPERATIONS
2.0 Thread rolling
Straight or tapered threads are formed.
Advantages:
-Surface finish
good
-Long life
- Thread strength
is good

28. DEFECTS IN ROLLED PARTS
1.0 Surface Defects
It includes scale, rust, cracks and pits due to impurities and inclusion
2.0 Internal Structural Defects
Strain on the material should adjust.

29. DEFECTS IN ROLLED PARTS
3.0 Other Defects
a) Homogeneous deformation of element across the width
Due to decrease in thickness for the elements near the centre will be mainly converted
into increase in length and near the edge the decrease in thickness is converted into
lateral spread.
b) Homogeneous deformation in the thickness section
Due to reduction in height is converted into increase in length and the thickness of the
sheet does not undergo the same lateral deformation.
c) Folds
It is created during plate rolling if the reduction per pass is very small.
d) Lamination
Due to incomplete welding of pipe and blowholes during the rolling process the internal
defects such as fissures are created.

30. CLASSIFICATION OF DRAWING
1.0 WIRE DRAWING
Diameter less than 16mm has drawn in the form of wire coil.

31. CLASSIFICATION OF DRAWING
2.0 ROD DRAWING
Placing the hot drawn bar through a die of which the bore size conforms to the
finished size of product.

32. CLASSIFICATION OF DRAWING
3.0 TUBEDRAWING
Cylinders and Tubes are made by extrusion process.
a) Tube Sinking b) Tube mandrel

33. CLASSIFICATION OF DRAWING
3.0 TUBE DRAWING
c) Tube Plug

34. CLASSIFICATION OF DRAWING
4.0 DEEP DRAWING
To draw the cup shaped parts from the metals.

35. EXTRUSION
Heated metal is compressed
and forced through a suitable
shaped die – Hot Extrusion.
Cold extrusion is non heated
metal but force is required
and used for commercial
metals.

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

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

38. TYPES OF EXTRUSION
2.0 COLD OR IMPACT EXTRUSION