Connection of copper-tungsten alloy to copper alloy
In the field of electrical contact, because copper-tungsten alloy has good electrical conductivity, high voltage value, strong breaking current ability, arc ablation resistance, strong material transfer resistance, excellent fusion welding resistance, and low contact resistance excellent performance. Therefore, tungsten-copper alloy has long been used as the contact material of high voltage switching appliances. Copper-tungsten alloy should be connected with copper alloy to make a whole contact, so as to take into account the interface bonding strength and conductivity of the electrical contact parts.
Common high pressure contact connection has the following methods:
1. The soldering
Because of the characteristics of small deformation during welding, the dimensional accuracy is easy to control, and the connection of dissimilar materials becomes very convenient. Due to the restriction of brazing welding technology, the shape of the joint surface is limited to a certain extent.
2. Hot isostatic pressure diffusion welding
Diffusion welding should make the surface to be welded in contact with each other, and increase the physical contact by making the interface produce liquid phase or trace plastic deformation. The connected contact joint has good quality, high connection strength and small deformation. The requirements of the joint surface are very high, so its application is limited and the cost is high.
3. Electron beam welding
Electron beam welding without solder, no weld structure, fast connection speed, small heat affected zone, high welding strength, good joint quality. However, since electron beam welding is still hot fusion welding, the copper near the weld will also undergo annealing and soften, thus affecting its performance. In addition, the binding surface of electron beam welding must be flat, which also limits its application.
With the increase of power grid capacity, higher requirements are put forward for contact conductivity and interface bonding strength.
