Effects of Sheet Surface Conditions on Electrode Life in Resistance Welding Aluminum The surface of aluminum sheet was cleaned with three different methods, then each surface was tested as to its effect on electrode life

The relatively short elec- trode life in welding aluminum sheets has been a bottleneck for large-scale produc- tion of aluminum vehicles. The rapid de- terioration of electrodes during resistance welding aluminum is the collective conse- quence of high pressure, high tempera- ture, and a rapid metallurgical (alloying) process. This study systematically investi- gated the effects of sheet surface condi- tions on electrode life. Using 2-mm 5A02 aluminum sheets, a schedule conducive to electrode life was used for testing the ef- fects of sheet surface conditions. A three- phase, direct-current pedestal-type resis- tance spot welding machine was used, and the electrodes lasted for about 200 welds for sheets with untreated or original sur- faces, up to 1700 welds when they were electric-arc cleaned, and more than 2000 welds if the sheets were degreased or chemically cleaned. This investigation also shows that the appearance of an electrode after a small number of welds provides useful information on the electrode life using the same welding schedule.