What happens to the electrode pressure after the weld current has ceased?

What happens to the electrode pressure after the weld current has ceased?

• A. Pressure is immediately released
• B. Pressure is maintained until the weld solidifies
• C. Pressure is increased to cool the weld faster
• D. Pressure switches to forge pressure

Answer: (B)

In resistance welding, the electrodes keep a clamping force on the joint while current is applied to form heat and a weld nugget. After the weld current stops, the metal at the joint is still hot and molten. Maintaining that electrode pressure during this cooling and solidification phase confines the molten metal, supports the nugget as it forms, and helps prevent expulsion or misalignment. Only after the nugget has solidified is the pressure released or reduced in a controlled manner. Releasing pressure immediately could let the molten metal flow or the nugget deform, leading to a weak or defective weld. Increasing pressure to speed cooling isn’t how cooling is controlled in this process and could cause damage or expulsion. Switching to forge pressure isn’t relevant to this welding method, which relies on electrical heating and clamping rather than forging pressure.

In resistance welding, the electrodes keep a clamping force on the joint while current is applied to form heat and a weld nugget. After the weld current stops, the metal at the joint is still hot and molten. Maintaining that electrode pressure during this cooling and solidification phase confines the molten metal, supports the nugget as it forms, and helps prevent expulsion or misalignment. Only after the nugget has solidified is the pressure released or reduced in a controlled manner.

Releasing pressure immediately could let the molten metal flow or the nugget deform, leading to a weak or defective weld. Increasing pressure to speed cooling isn’t how cooling is controlled in this process and could cause damage or expulsion. Switching to forge pressure isn’t relevant to this welding method, which relies on electrical heating and clamping rather than forging pressure.