Copper Brazing

Copper and its alloys are used in a wide variety of applications due to their properties. The family of copper and their alloys have excellent corrosion resistance and formability. Brazing is the most suitable metal joining process for all types of copper alloys but with a little bit of precaution. The different copper brazing processes like brazing brass copper, brazing steel copper or brazing aluminum copper etc. should be performed with enough precautions because if proper precautions aren't taken during brazing then it may lead to cracking, distortion, and unacceptable softening. They have higher thermal expansion than steels, and it plays an important role when brazing dissimilar metals.

Brazing Filler Metals
The most commonly used filler metals for brazing copper and its alloys:

Silver Brazing Filler Metals
Silver brazing alloys are the most used filler metals for brazing copper and its alloys. The percentage of silver, copper, zinc, and cadmium vary in different products). Their brazing temperatures should lie in the range from 1145° F to 1600° F (620° to 870°C).

Copper Brazing Filler Metals
Copper brazing alloys are also widely used for brazing copper and their alloys. The primary constituents are zinc, phosphorous, silver, etc.

Atmospheres
Combustion fuel gases are useful and economical atmospheres for brazing most copper base alloys. Dissociated ammonia and hydrogen are also useful, except for oxygen-bearing coppers. Inert-gas atmospheres, such as argon and helium, and also nitrogen may be used for all copper base alloys without harmful effects. Vacuum atmosphere is suitable for copper and copper alloys when the alloys are essentially free of elements having high vapor pressure at the brazing temperature.

Safety
Some brazing filler alloys contain cadmium and zinc, some base metals contain lead, zinc or beryllium, while some fluxes contain fluorides. When such material are used, proper ventilation must be provided to protect the personnel.