Which of the following falls under the category of the fusion or non-pressure welding?

Fusion and Non-Pressure Welding:

• Welding is a process of joining two materials, typically metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint.
• There are two main categories of welding: fusion welding and non-fusion welding (also called solid-state welding).

Fusion Welding:

• In fusion welding, the materials being joined are melted together. This can be done using various energy sources, such as an electric arc, gas flame, or laser.
• Examples of fusion welding include Metal Arc Welding, TIG (Tungsten Inert Gas) Welding, and MIG (Metal Inert Gas) Welding.

Non-Fusion (Solid-State) Welding:

• Non-fusion welding, or solid-state welding, does not involve melting the base materials. Instead, the materials are joined through the application of pressure, sometimes in combination with heat.
• Examples of non-fusion welding include Explosive Welding, Ultrasonic Welding, Friction Welding, and Resistance Welding.

Detailed Explanation:

• Explosive Welding: This process uses controlled explosions to force two metals together at high pressure. This is a solid-state welding process because it does not involve melting the materials.
• Ultrasonic Welding: This process uses high-frequency ultrasonic vibrations to create a solid-state weld. The vibrations generate heat through friction, which bonds the materials without melting them.
• Metal Arc Welding: This is a fusion welding process where an electric arc is used to melt the workpieces and a filler material to form the weld pool. This process involves melting, so it falls under the category of fusion welding.
• Resistance Welding: This process generates heat through electrical resistance to join materials. It is considered a solid-state welding process as it does not melt the base materials.

Correct Answer:

Based on the explanation above, the correct answer is:

• Option 3: Metal Arc Welding falls under the category of fusion welding.