Ultrasonic Welding Process Of Copper And Aluminum

Mainly in order to reduce the cost and weight, because the density of aluminum is about 1/3 of copper, the price is about 1/5 of copper, so many occasions to use aluminum instead of copper, especially in the power industry, copper and aluminum welding also appeared. But the surface of copper and aluminum are very easy to oxidize, especially the oxide film of aluminum is very strong, high temperature resistance (melting point up to 2050℃), and the resistance is very large, if the machine city connection, in the power operation contact is not stable, often smoke, explosion phenomenon, easy to cause fire and other serious consequences. Generally speaking, the welding of copper and aluminum can adopt fusion welding, pressure welding and brazing welding, ultrasonic welding.

Difficulties in ultrasonic welding of copper and aluminum

1. The welding of copper and aluminum belongs to dissimilar metal (non-ferrous) welding, which is much more difficult than copper-copper and aluminum-aluminum welding.

2, copper, aluminum are easy to be oxidized, generated in the welding process of high melting point oxides, so that the weld metal is difficult to completely fuse, bring difficulties to welding.

3, the welding joint of copper and aluminum is brittle, easy to crack, in the fusion welding of copper and aluminum, near the copper side of the weld is easy to form CuAl2 eutectic, distributed near the grain boundary, easy to produce intergranular cracks.

4, copper and aluminum melting point difference is large, in fusion welding, aluminum melting when copper remains solid state, when copper melting, aluminum has been melted a lot, increase the difficulty of welding.

5, weld prone to porosity, because copper and aluminum are very good thermal conductivity, welding molten pool metal crystallization fast, high temperature gold reaction gas too late to escape, so the generation of porosity.

Through the purchase of imported advanced ultrasonic welding equipment, equipment with the ultrasonic welding machine can simultaneously weld aluminum copper, silver, nickel and other conductive metal thin materials for the implementation of spot, strip welding, can be widely used in automotive electrical appliances, electronic motors, electrical lead terminals, copper and aluminum composite bar, wire harness, end piece, pole piece lug welding connection. Ultrasonic metal welding is the use of tens of thousands of times per second of high-frequency vibration wave transfer to the surface of two metal workpiece to be welded, and then impose a certain pressure, so that the metal surface friction and formation of molecular layer between the dissolution, so as to achieve the purpose of welding.