Copper-aluminum flux-cored wire is actually a zinc-aluminum alloy for brazing of copper and aluminum;
Direct brazing/welding between copper and aluminum alloys (such as using aluminum wire flame brazing or resistance welding), a large amount of CuAl2 brittle eutectic metal compounds are generated at the copper-aluminum interface, which will lead to poor interface mechanical strength and corrosion resistance, which may affect the interface The service life does not even meet the requirements for use.
Therefore, flux-cored wire of ZnAl2 or ZnAl22 alloy is usually used for brazing. Zn can be well wetted with Cu and Al without forming brittle compounds.
The melting point of Zn alloy is very low (the melting point of Zn is about 420 ° C), so the flux for aluminum alloy cannot be used for Zn alloy. CsAlF Complex is suitable for brazing of ZnAl but the flux is expensive.
Compared with ZnAl2, ZnAl22 can provide better post-weld mechanical properties and a higher melting point.
Copper-aluminum flux-cored wire is widely used for welding of transformers, reactor joints and pipelines of household appliances.
There are also customers who use copper-aluminum flux-cored wire for brazing of pipe joints for air-conditioning heat exchangers.
