Hot And Cold Working Process. Its Advantages & Disadvantages

The hot and cold working process is a metal forming process. In this article, we have described both the hot and cold working processes.

Table of Contents

Hot Working Process:

Hot-working is a metal forming process in which the metal is permanently (plastically) distorted so that it can be shaped into different kinds of geometry for various industrial and household purposes.

This process is not only used for changing the geometry but also used for changing the properties like yield strength, hardness, ductility, etc. of the metal.

The hot-working process is always done above the recrystallization temperature but below the melting point of the metal. The recrystallization temperature differs according to the metal or alloy we are using.

Recrystallization Temperature-

The recrystallization temperature is defined as the temperature at which a metal distorted grains at the molecular level are replaced by new distorted-free grains and gives a new defeats free crystal structure to the metal.

The recrystallization temperature is generally taken as 60% of the melting point of that particular metal.

For example – If a metal is having 100°C as its melting point then 60°C will be considered as its recrystallization temperature.

Cold Working:

Cold working is also a metal forming process that is used for changing the geometry of the metal for various commercial and non-commercial purposes.

Like the hot working process, this process is also used for changing the properties of the metal along with its geometry.

But the cold working process is done below the recrystallization temperature. This is one of the biggest differences between hot working and cold working processes.

Since the cold working process is done below recrystallization temperature then changes taking place in the crystal structure of the metal are out of the question. There will be no change in the crystal structure of the metal.

Advantages of the Hot working process:

Since metal is heated above its recrystallization temperature developing residual stress in metal is out of the question.
The geometry of the metal can be changed easily since it is heated at a very high temperature. It’s required less force to do it.
The chances of occurring of strain hardening in metal are very low.
The defective grains are replaced by new grains which result in giving a new crystal structure to the metal.
It increases certain mechanical properties like ductility, strength, toughness, etc. while on other hand it doesn’t affect properties like corrosion resistance and fatigue resistance.
There are very low chances of getting cracks in the metal.

Disadvantages Of The Hot Working Process:

Required high temperature which is not always suitable for the workplace.
It’s only suitable when high deformations are required.
The surface finish we obtain in this process is not ideal.
The dimension control in this process is very difficult.
It is a very expensive process.

Advantages Of The Cold Working Process:

It increases the mechanical property like hardness, yield strength, tensile strength, etc.
Required less temperature which is suitable for the workplace.
It’s suitable when minimum deformations are required.
The surface finish we obtain in this process is ideal.
The dimension control in this process is very easy.
It is not an expensive process.

Disadvantages Of Cold Working Process:

The range of geometrical deformation we can obtain is limited.
Decrease corrosion resistance property of the metal.
Very high chances of occurring strain hardening in the metal.
Required high force to change the geometry of the metal.
There are very high chances of getting cracks in the metal.
The defective grains are not replaced by new grains. So, the formation of a new defect-free crystal structure in the metal is out of the question.

I am going to end my blog post on the hot and cold working process.

Thanks for reading!

Ta! Da!

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