During the resistance welding process the electrode face is subjected to extreme temperatures for short periods of time. To prevent premature wear, water cooling is necessary for the resistance welding electrodes. The technical term for this wear and resultant deformation is annealing. In the case of spot welding the face will begin to take on the shape of a mushroom. As this face grows the weld quality suffers and eventually weld quality failure occurs. Prevention or retarding this mushrooming is very important. One of the most important items to control is the time at temperature that the electrode weld face sees. One method of control is by cooling the electrode. The second benefit of this is that it will also cool and solidify the weld nugget during the hold period of the weld cycle.
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