White copper alloys containing elements such as manganese, iron, zinc and aluminum are called composite white copper (that is, white copper containing more than three elements), including iron white copper, manganese white copper, zinc white copper and aluminum white copper. In complex white copper, the symbol of the second principal element and the number group of components other than copper content indicate the content of various elements. For example, BMn3- 12 indicates that the nickel content is about 3% and the manganese content is about 12%.
There are four types of complex white copper:
① white iron and copper: the models are Bfe- 1.5(Fe)-0.5(Mn), bfe10-1(Fe)-1(Mn), bfe30-1(Fe The addition of iron in white iron copper is less than 2%, which prevents corrosion and cracking. It is characterized by high strength and can obviously improve the corrosion resistance, especially the corrosion resistance of flowing seawater.
② Manganese white copper: the models are BMn3- 12, BMn4.0- 1.5 and BMn43-0.5. Manganese white copper has a low temperature coefficient of resistance, can be used in a wide temperature range, and has good corrosion resistance and good processability.
③ Zinc white copper: models are BZn 18- 18, BZn 18-26, bzn 15-12 (Zn)-1.8 (Pb), etc. Zinc-white copper has excellent comprehensive mechanical properties, excellent corrosion resistance, good cold and hot formability and machinability. It can be made into wires, rods and plates, and used to manufacture precision parts in the fields of instruments, meters, medical instruments, daily necessities, communications and so on.
④ Aluminium white copper: models are Bal 13-3 and Bal 16- 1.5. It is an alloy formed by adding aluminum on the basis of copper-nickel alloy, and its density is 8.54-0.3. The properties of the alloy are related to the ratio of nickel content to aluminum content in the alloy. When Ni: Al = 10: 1, the properties of the alloy are the best. Commonly used aluminum white copper is Cu6Ni 1.5Al, Cu 13Ni3Al, etc. It is mainly used for various high-strength and corrosion-resistant parts in shipbuilding, electric power, chemical industry and other industrial sectors.
Ordinary white copper
Copper-nickel binary alloy (namely binary white copper) is called ordinary white copper. In ordinary white copper, the letter B indicates the nickel content. For example, B5 indicates that the nickel content is about 5% and the rest is about copper content. The models are B0.6, B 19, B25 and B30.