The classification of copper alloys is customarily classified by color, which is generally divided into four categories:
1. Red copper: refers to pure copper, the main varieties are oxygen-free copper, red copper, phosphorus deoxidized copper, silver copper;
2. Brass: refers to an alloy based on copper and zinc, which can be subdivided into simple brass and complex brass. In complex brass, the third component is named nickel-brass, silicon brass, etc.;
3. Bronze: refers to copper-based alloys other than copper-nickel and copper-zinc alloys. The main varieties are tin bronze, aluminum bronze, and special bronze (also known as a high copper alloy);
4. Cupronickel: refers to copper-nickel alloys;
