How to choose the electrode material of the medium frequency spot welding machine?

How to choose the electrode material of the medium frequency spot welding machine? Spot welding electrode head through the current of thousands to tens of thousands of amperes, withstand the voltage of 9.81~49.1MPa, instantaneous temperature of 600℃~900℃. Therefore, the electrode is required to have good electrical conductivity, thermal conductivity, thermal hardness and high corrosion resistance.

Spot welding electrodes are made of copper alloys. In order to improve the performance of copper alloy electrodes, it is generally necessary to undergo strengthening treatment, such as: cold processing strengthening, solid solution strengthening, aging precipitation strengthening and dispersion strengthening. The performance of the electrode also changes after different strengthening treatments. When cold-rolled steel plates, galvanized steel plates, stainless steel or aluminum plates need to be spot-welded, appropriate electrode materials should be selected according to the properties of the plate materials.

The selection of electrode materials for spot welding galvanized steel plate should reduce the stain and deformation of the electrode during spot welding, which requires high hardness, good electrical and thermal conductivity of the electrode at high temperature, and small alloying tendency with zinc.

The electrode life of galvanized steel plate welding with several electrode materials is longer than that of cadmium copper electrode. Because although the electrical and thermal conductivity of cadmium copper is better, it is generally believed that the adhesion of zinc is less, but in fact, due to its low softening temperature, the impact of high temperature hardness is greater. The high temperature hardness of zirconium copper is higher, so its life is also longer. Although the high temperature hardness of beryllium diamond copper is higher, because its conductivity is much worse than that of chromium-zirconium copper, the conductivity and thermal conductivity play a major role in the influence of its life, and its electrode life is relatively low.

In addition, the use of tungsten (or molybdenum) embedded composite electrode welding galvanized steel plate, its life is also higher, although the conductivity of tungsten, molybdenum is low, only about 1/3 of chromium copper, but its softening temperature is high (1273K), high temperature hardness (especially tungsten), the electrode is not easy to deformation.