IMPORTANT FEATURES OF FORGING
• Forging is a deformation processing of materials through compressive stress. It is carried out
either hot or cold.
• Forging is the process by which metal is heated and is shaped by plastic deformation by suitably
applying compressive force
• Usually the compressive force is in the form of hammer blows using a power hammer or a press.
Presses or hammers powered by compressed air,electricity,hydraulics or steam.
1. Drawn out: length increases, cross-section decreases
2. Upset: length decreases, cross-section increases
3. Squeezed in closed compression dies: produces multidirectional flow
• Produce a piece that is stronger than an equivalent cast or machined part
• Its refines the internal grain structure and improves physical properties of the metal (such as
strength, ductility and toughness)
• These are consistent from piece to piece, without any of the porosity, voids, inclusions and other
• Have high strength to weight ratio (design of aircraft frame members.)
• Production forging involves significant capital expenditure for machinery, tooling, facilities and
• A high-temperature furnace is required to heat ingots or billets
• Applications of forging include
4. Turbine disk,
5. Crank shaft,
6. Connecting rod,
7. Valve bodies,
8. Small components for hydraulic circuits etc.
CLASSIFICATION OF FORGING
• Based on type of loading(forging equipment's), it is classified in to following
1. Hammer forging
2. Press forging
• Based on the operating temperature of the workpiece, it is classified in to following
1. Hot forging
2. Warm forging
3. Cold forging
• Based on arrangement of dies,it is classified in to following
1. Open die forging
2. Closed die forging
STEPS INVOLVED IN FORGING PROCESS
• Sawing the extruded or continuously cast feedstock,
• Heating the blank,
• Upsetting or bending,
• Forging (rough and final forging),
• Heat treatment
• Final inspection.
This is the operation in which metal gets elongated with a reduction in the cross sedation area. For
this, a force is to be applied in a direction perpendiaulant to the length axis.
• Up setting:
• This is applied to increase the cross sectional area of the stock at the expanse of the length. To
achieve the length of upsetting force is applied in a direction parallel to the length axis, for example
forming of a bolt head.
• It a similar to material cross-section is decreased and length increased. To do this; the bottom fuller is
kept in angle hole with the heated stock over the fuller .The top fuller is then kept above the stock
and then with the sledge hammer, and the force is applied on the top fuller.
It is a process in which the metal piece is displaced to the desired shape by striking between two dies
edging is frequently as primary drop forging operation.
Bending is very common forging operation. It is an operation to give a turn to metal rod or plate. This is
required for those which have bends shapes.
It is a process of producing holes in motel plate is placed over the hollow cylindrical die. By pressing the
punch over the plate the hole is made.
Swaging is done to reduce and finish work for desire size and shape, usually either round or hexagonal. For
small jobs top and bottom swage pair is employed, where as for large work swage block can be used.
Swaging is a special type of forging in which metal is formed by a succession of rapid hammer blows
Swaging provides a reduced round cross section suitable for tapping, threading, upsetting or other
subsequent forming and machining operations.
• Flating and setting down:
• Fullering leaves a corrugated surface on the job. Even after a job is forged into shape with a hammer, the
marks of the hammer remains on the upper surface of the job. To remove hammer marks and corrugation
and in order to obtain a smooth surface on the job, a flatter or set hammer is used.
• This is the traditional forging operation done openly or in-openly dies by the village black smith
or modern shop floor by manual hammering or by the power hammer. The process involves
heating the stock in the black smith hearth and then beating it over the anvil. To get the desire
shape the operator has to manipulate the component in between the blows.
• Roll forging is a process where round or flat bar stock is reduced in thickness and increased in
• Roll forging is performed using two cylindrical or semi-cylindrical rolls, a heated bar is inserted
into the rolls and when it hits a spot the rolls rotate and the bar is progressively shaped as it is
rolled through the machine.
• The piece is then transferred to the next set of grooves or turned around and reinserted into the
• This continues until the desired shape and size is achieved. The advantage of this process is
there is no flash and it imparts a favorable grain structure into the workpiece.
• Rotary forging:
In this process the punch is given orbital rocking motion while pressing the workpiece. As a result
of this the area of contact between work and punch is reduced. Therefore lower forging loads are
sufficient. The final part is formed in several smaller steps. Example of parts produced by this
process include bevel gears, wheels, bearing rings