During upset welding, what is the typical sequence of actions?

During upset welding, what is the typical sequence of actions?

• A. The parts are brought into solid contact, current is passed through the contact area to reach forging temperature, then the pieces are pressed together
• B. The parts are heated separately then welded
• C. The ends are heated by flashing while separated
• D. The joint is formed without applying pressure

Answer: (A)

Upset welding relies on resistance heating at the interface while the parts are held under pressure to forge a bond. The typical sequence starts by clamping the pieces and bringing their ends into solid contact. An electric current is then passed through the contact area, heating it by resistance until it reaches forging temperature. Once the interface is hot enough, pressure is applied to push the surfaces together, allowing plastic deformation and diffusion to form the weld and to expel any excess material as a small flash. After the joint has formed, the current is stopped and the assembly remains under pressure as it cools and solidifies. This approach is distinct from heating pieces separately, heating ends while they’re separated, or forming the joint without applying pressure, which are not how upset welding is carried out.

Upset welding relies on resistance heating at the interface while the parts are held under pressure to forge a bond. The typical sequence starts by clamping the pieces and bringing their ends into solid contact. An electric current is then passed through the contact area, heating it by resistance until it reaches forging temperature. Once the interface is hot enough, pressure is applied to push the surfaces together, allowing plastic deformation and diffusion to form the weld and to expel any excess material as a small flash. After the joint has formed, the current is stopped and the assembly remains under pressure as it cools and solidifies.

This approach is distinct from heating pieces separately, heating ends while they’re separated, or forming the joint without applying pressure, which are not how upset welding is carried out.