Patent ID: 8455784

Claim:
A method of welding two or more workpieces employing a motion-controlled electrode that reduces temperature and residual stresses at an associated workpiece-to-electrode interface, the method comprising: applying, during a first period of time, a first electrode force to the workpieces to be welded, and applying a weld current that causes heating of an associated workpiece-to-workpiece faying surface, the first electrode force being applied at a first electrode stroke; determining a temperature of the faying surface indicative of a weld nugget formation thereat, and in response thereto reducing the electrode force to a second level during a second period of time while maintaining a constant electrode stroke; during a third period of time, further reducing the electrode force to a third level while simultaneously reducing the electrode stroke to a second level; and stopping the welding after the third period of time, resulting in a weld joint having reduced residual stresses and reduced likelihood of stress crack formation.