Forging

 “The process of giving a desired shape to a metal piece
by heating and hammering is known as forging”.

Hamza Abdullah Khan... IIUI

 It increase the strength and toughness of the metals by
producing directional grains.

 It refines the structure of the metal and thus renders it
more dense.

 The internal defects like segregation, cracks and
porosity are eliminated.

 A forged component has the ability to withstand
higher load during service.

 A forged components can be produced to close
tolerance.

 It reduces the machining time, material and labor
considerably.

 Brittle material like cast iron cannot be forged.

 Complex shapes can easily be produced by casting and
not by forging.

 Cost of forging dies is high.


 Upsetting:
upsetting is the process in which the cross
sectional diameter of a hot metal work piece is
increased with a corresponding reduction in its length.
During this process the hot metal piece is held in a tong
and placed on the anvil in vertical position and then is
stroke with a hammer.


 It is also known as drawing down.

 Exactly the reverse of upsetting

 Contrary to upsetting this process is used to reduce the
thickness/width/diameters or increasing the length of
red hot workpiece.


 Cutting operation is required for removing extra metal
from the job.

 For cutting operation three major things required,
hammer, cutting tool set and the stock.


 The process of giving the desired angle or curves to a
hot metal work piece is known as bending.
 The process is done on the edge of anvil.
 Circular shaped, eye bolts, hooks or any other types of
bent shape can be prepared with this operation.


 Punching is the operation in which a rough hole is
made into the hot workpiece by forcing a punch
through it.

 A red hot job is placed on the anvil and by using a
sledge hammer, the punch is forced to the pierce the
metal upto half of its thickness.


 Then by inverting the workpiece same process is
repeated at the same point to get a rough hole.


 Is an operation of finishing and enlarging the hole by
hammering a tapered drift into the hole until the
required bore size is reached.

 Is similar to punching and followed by it.


 Swaging is the operation of reducing and finishing a
work piece to different desired shapes usually circular,
hexagonal and square.
 Swaging operation is performed with the help of
swages and swag blocks.
 Swages are used for small jobs.
 Swag blocks are used for large jobs.


 It is the operation of reducing the thickness of a work
piece.
 In this process the bottom fuller is held in the hole of
the anvil.
 Hot work piece is placed in the grooves of the lower
fuller and then the top fuller is placed over it.
 The hammering operation is carried out until the
piece gets squared thickness.


 This operation is performed to level the job surface.

 The red hot metal work piece is placed on the anvil
and is stroked hardly using hammer set to flatten the
metal work piece.


 The process of joining two metals by heating and
hammering is known as forge welding.
 The metal pieces to be joined are cleaned and heated
in a furnace up to the welding temperature.
 With the help of tongs these are kept overlapping each
other at the one of their ends on the anvil and are
subjected to hammering.


 Forge/Furnace/Hearth : Heating furnace
 Anvil :Supporting Tool
 Hammers & set Hammers : Striking Tool
 Tongs: Holding Tool
 Chisels: Cutting Or Shaping Tool
 Fullers: Grooving Tool
 Swages & Swage Block: Shaping Tools


Hammers

Tong chisel
Swage Block

 Pitting: occurs on the surface of forging due to scales.

 Cold shuts or laps : Short cracks that occurs on the
corners of the surface that are at right angles to each
other

 Die shift : Caused due to misalignment between to
halves of forging dies.

 Dents :Caused due to careless working.

 Oxidation & Decarburization : Occur due to
overheating of stock.

 Fins and rags : Small projection or loose metal driven
into the forging surface


 Some other common defect are
(a) Incomplete filing of dies
(b) Burnt and overheated metals
(c) Flakes: Internal breaks and rupture
(d) Incorrect size of forging
(e) Tears
(f) Blowholes
(g) Internal cracks


Forging

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