RESISTANCE SPOT WELDING THIN GAUGE STEELS

摘要

Resistance spot welding of a thin-gauge steel workpiece to another steel workpiece is achieved by through the combined use of specific spot welding electrodes and a pulsating welding current. Each of the spot welding electrodes has a weld face that is smaller in diameter than a typical steel spot welding electrode. And the pulsating welding current that is used in conjunction with the smaller-sized spot welding electrodes includes at least two stages of electrical current pulses.

主权项

1. A method of resistance spot welding a thin-gauge steel workpiece to another steel workpiece, the method comprising:
providing a steel workpiece stack-up that includes a first steel workpiece and a second steel workpiece that overlap to form a faying interface between the two steel workpieces at a predetermined weld site, the first steel workpiece having a thickness that ranges from about 0.3 mm to about 1.0 mm at least at the weld site and the second steel workpiece having a thickness that is equal to or greater than the thickness of the first steel workpiece at least at the weld site; clamping the steel workpiece stack-up between a first spot welding electrode, which is brought into contact with the first steel workpiece, and a second spot welding electrode, which is brought into contact with the second steel workpiece, the first spot welding electrode having a first weld face that has a diameter that ranges from about 3.0 mm to about 4.5 mm, the second spot welding electrode having a second weld face that has a diameter that ranges from about 3.0 mm to about 4.5 mm, each of the first and second weld faces being flat or having a radius of curvature down to about 15 mm, the first and second weld faces being diametrically opposed from each other when clamped onto the steel workpiece stack-up; passing a first stage of one or more pulses of electrical current through the steel workpiece stack-up and between the first and second weld faces at the weld site, each of the pulses of electrical current in the first stage achieving a peak amperage; and passing a second stage of one or more pulses of electrical current through the steel workpiece stack-up and between the first and second weld faces at the weld site after passing the first stage of one or more pulses of electrical current, the pulses of electrical current in the second stage achieving a greater peak amperage than the pulses of electrical current in the first stage, and wherein the second stage of one or more pulses of electrical current grows a molten weld pool at the faying interface of the first and second steel workpieces that was initiated during the first stage.