Correct Answer - Option 3 : 2, 3, and 4
Concept:
Butt welding is the process in which two pieces of metal are placed end-to-end without overlap and then welded along the joint.
In a butt joint, the surface of the workpiece being joined is on the same plane and the weld metal remains within the plane of the surfaces.
Butt welding is accomplished by hitting of two pieces of metal or applying pressure, or doing both of these.
Types of butt welding:
→ Flash butt welding
→ Resistance butt welding
Flash butt welding is a type of resistance welding
All aluminum alloys are made from flash welding
Upset butt welding is a form of resistance welding which is used for welding non-ferrous materials of a smaller cross-section like rods.
→ Percussion welding creates a high-temperature arc that is formed from a short quickly electrical discharge. Immediately following the electrical discharge, pressure is applied which forges the materials together, this type of joining brings the material together. It is a self-timing spot welding method.
Hence option '3' is correct
