”The influence of forging pressure on the weld nugget has been discussed in several articles in this blog:

“WHY IS THE CONTROL OF PRESSURE IMPORTANT IN RESITANCE WELDING?"

The same principals apply. The welds occur faster and frequently overlap. Cooling is frequently external (flood cooling).
Too little forging pressure leads to expulsion. Too much forging pressure reduces all of the resistances and results in a higher current demand.

“HOW ARE FORCE AND PRESSURE RELATED?”

“HOW DO FORCE AND PRESSURE CONTAIN EXPULSION?”

A simple summary of these might be:
• Forging pressure can increase or decrease the weld current
• Forging pressure can change the resistance at the weld interface (actually all interfaces)
• Forging pressure can be used to control weld expulsion
• Forging pressure may increase weld strength through forging the weld nugget

 

Remove the electrodes and insert two “SEAM WELDING WHEELS” The same principals apply. The welds occur faster and frequently overlap. Cooling is frequently external (flood cooling).
Too little forging pressure leads to expulsion. Too much forging pressure reduces all of the resistances and results in a higher current demand.

Reference: RWMA – Resistance Welding Manual Section 4