Forging

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

Introduction:

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.

Advantages of Forging:


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.

Advantages of Forging:


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.

Disadvantage of forging:


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.

Forging Operations:


Upsetting:


Upsetting:


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.

Drawing out:


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.

Cutting:


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.

Bending:


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.

Punching:


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

Punching:


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.

Drifting:


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.

Swaging:


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.

Fullering:


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.

Flattening:


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 welding:


Forging Temperature:


Forge/Furnace/Hearth : Heating furnaceAnvil :Supporting ToolHammers & set Hammers : Striking ToolTongs: Holding ToolChisels: Cutting Or Shaping ToolFullers: Grooving ToolSwages & Swage Block: Shaping Tools

Forging Tools:


Forging Tools

AnvilHammers

Tong chiselSwage 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.

Defects in forging:


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

Defects In Forging


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

Defects in forging:

Forging

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caused due

swag blocks

rough hole

cutting operation

forging dies

hole

workpiece