Types Of Welding – Classification of welding processes

Welding is a process of permanently joining two parts by the application of heat and (or) pressure. Filler metal may be added to the joint depending on the welding process and the type of joint.

The American Welding Society (AWS) has recognized more than 50 different types of welding processes, some of them are very popular among the industries such as Shielded metal arc welding (SMAW) or stick welding, Gas metal arc welding (GMAW) also known as MIG/MAG welding process, Gas tungsten arc welding (GTAW) or TIG Welding, Submerged arc welding (SAW) and Flux-cored arc welding (FCAW), etc. Whereas, some are very specific and limited to a few industries such as Ultrasonic welding (USW) and Diffusion welding (DFW), etc.

Welding processes are broadly divided into two types;

1. Pressure Welding Process

2. Fusion Welding Process

In the pressure welding process, joining is done by the application of external pressure or force at the area of contact, which causes more or less plastic deformation of both contact surfaces. The facing surfaces are heated to some extent in order to permit or facilitate permanent bonding.

Usually, the heat used during the pressure welding process is much less than the melting point of the base metal. Generally, the additional filler metal is not required during these types of welding techniques. Resistance welding and Diffusion welding are examples of the pressure welding process.

Whereas, In the Fusion welding process, joining is done by melting the base metals in the area of contact. No external pressure or force is required during fusion welding processes and very often filler metal is also used.  The arc welding process is one of the most popular welding processes, which belongs to the family of the fusion welding process. 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. Oxyfuel Gas Welding

3. Electron beam welding

4. Laser beam welding

5. Thermit Welding

6. Electroslag Welding

Some of the pressure welding processes are:

1. Resistance Welding

• Spot Welding
• Seam Welding
• Projection Welding
• Flash Welding
• Upset Welding
• Percussion Welding

2. Diffusion welding (DFW)

3. Friction welding (FRW)

4. Ultrasonic welding (USW)

5. Cold Pressure Welding

6. Forge welding

7. Explosion welding (EXW)

This is how the welding processes are classified. To read more about these welding processes please click on the below links;

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)

Oxyfuel Gas Welding

For theoretical and practical lectures on welding please click the link below;