Observations on Spot Welding Aluminum for Automotive Applications

These observations were made during tip-life tests in spot welding mill finish aluminum alloys. Nugget-formation quality can be monitored effectively and non-destructively by use of a motion transducer. Interface dynamic-resistance can be monitored by electrode to electrode voltage drop. Cumulative deterioration of the electrodes can be measured semi-quantitatively by micrometric profile recording. These techniques permit short-run schedules for screening the effectiveness of surface treatments.

It is also shown that nugget shear load can be estimated when gauge, nugget diameter, and ultimate tensile strength are known.