Advantages of spot welding projection welding compared with spot welding

Update:30 Jun 2020

1 spot welding machine can weld multiple welding points […]

1 spot welding machine can weld multiple welding points at the same time in one welding cycle, which not only has high productivity, but also has no diversion effect. Therefore, solder joints can be arranged on narrow parts without being limited by the pitch.

2 Because the current is concentrated on the bumps and the current density is large, it can be welded with a small current and can reliably form a small nugget. In spot welding, it is difficult to form a nugget smaller than a certain size corresponding to a certain plate thickness.

3 The position of the bumps is accurate, the size is consistent, and the strength of each point is relatively uniform, so for a given strength, the size of the bump welding spot can be smaller than the spot welding.

4 Because the large flat electrode is used, and the bumps are designed on one workpiece, it can minimize the indentation on the exposed surface of another workpiece. At the same time, the current density of the large plane electrode is small, the heat dissipation is good, and the wear of the electrode is much smaller than that of spot welding, thus greatly reducing the maintenance and repair costs of the electrode.

High-strength alloy steels that can be hardened by spot welders are rarely convexly welded, but sometimes cross-welding of wires is performed. Because of the quenched structure, tempering between electrodes must be performed, and the electrode pressure should be higher than that of low-carbon steel.

Stainless steel projection welding is not difficult, but the phenomenon of nugget shift occurs in the transaction, you should pay attention to the selection of reasonable welding process parameters, and avoid using too small dot pitch.

Aluminum alloy has low strength. As soon as it is energized, the bumps squeeze and collapse, which does not play the role of concentrated current. Therefore, projection welding is rarely used, but it is sometimes used for projection welding of bolts and nuts.

Spot welding machine aluminum alloy projection welding has the same difficulties as spot welding. When projecting copper and copper alloys with high conductivity, electrodes embedded with W, MO or W-CU sintered alloy tips must also be used.

When the multi-strand copper wire is welded to the chromium-zirconium-copper base plate with lower conductivity, the type 2 electrode material can be used on the chromium-copper side. The surface of the tungsten-embedded electrode connected to the multi-strand copper wire has a groove, and the depth of the groove should not be greater than the radius of the multi-strand copper wire. The groove can gather multiple strands of copper wire together, which is conducive to forming a compact and mysterious joint.