Types Of Welding – Classification of welding processes

Before explaining the types of welding, Let’s understand the basic concept of welding i.e. What is welding?, Then we will understand the different types of welding.

What is Welding ?

Welding is a process of permanently joining two or more parts. It’s a kind of metallic bonding between two parts, which is permanent in nature. Heat and (or) pressure is required to achieve welding, very often additional filler metal is also used during welding.

There are more than 75 types of welding processes available today. Each welding process has its own advantages and disadvantages which makes it either more or less suitable for a particular application.

For example, Arc welding processes offer advantages such as portability and comparatively low cost, but are relatively slow. Laser Welding processes produce low heat inputs and fast welding speeds, but the equipment is very expensive and the joint fit‐up needs to be very accurate.

With Solid‐state welding processes, we can avoid many of the common weld defects, which generally occurs during solidification of molten weld pool, but these welding processes are very expensive and are often applicable for limited joint designs only.

Resistance welding processes are very fast and require no additional filler materials, but are generally applicable for thin sheet applications or very high production jobs such as seams in welded pipe.

Now, we shall learn about the different types of welding which are commonly used in industries;

Types of Welding:

Welding processes are broadly classified as fusion welding and solid state welding (Figure-1)

(Figure-1)

FUSION WELDING: In Fusion welding coalescence is done by melting the base metals by the application of heat. Required heat is generated by an electric arc formed between the electrode and the workpiece. Very often filler metal is also used. Commonly used fusion welding processes are:

1. Arc Welding

• SMAW (Shielded Metal Arc Welding or stick Welding)
• GMAW (Gas Metal Arc Welding or MIG welding)
• GTAW (Gas Tungsten Arc Welding or TIG Welding)
• SAW (Submerged Arc Welding)
• FCAW (Flux Cored ARC Welding)
• PAW (Plasma Arc Welding)
• Carbon Arc Welding 
• Stud Welding

2. Resistance Welding

• Resistance Spot Welding
• Resistance Seam Welding
• Resistance Projection Welding
• Flash Welding

3. Oxyfuel welding

4. Others

• Electron beam welding
• Laser beam Welding

SOLID STATE WELDING: In solid state welding, joining is done by the application of pressure alone or a combination of pressure and heat. Normally the base metal is not reached to the melting point, if heat is applied to obtain the coalescence and filler metal is not used. Some of the solid state welding processes are:

1. Diffusion welding (DFW)
2. Friction welding (FRW)
3. Ultrasonic welding (USW)
4. Cold Welding
5. Forge welding
6. Explosion welding (EXW)

In the following video, I have simplified the different welding processes and categorized for your easy understanding. Please watch this video and share your views as well as queries. I will be glad to answer your queries.