Introduction to Copper Alloys

Brass is a copper alloy with zinc as the main additive element. It has a beautiful yellow color and is collectively referred to as brass. Copper-zinc binary alloy is called ordinary brass or simple brass. Brass with more than three yuan is called special brass or complex brass. Brass alloys with a zinc content of less than 36% are composed of solid solution and have good cold working properties. For example, brass with a zinc content of 30% is commonly used to make bullet cases, commonly known as bullet case brass or seven-three brass. Brass alloys with a zinc content between 36% and 42% are composed of solid solutions and the most commonly used is the six-four brass with 40% zinc. In order to improve the performance of ordinary brass, other elements such as aluminum, nickel, manganese, tin, silicon, lead, etc. are often added. Aluminum can increase the strength, hardness and corrosion resistance of brass, but reduce its plasticity. It is suitable for marine condensers and other corrosion-resistant parts. Tin can improve the strength of brass and its corrosion resistance to seawater, so it is called naval brass and is used for ship thermal equipment and propellers. Lead can improve the cutting performance of brass; this kind of free-cutting brass is often used as parts of clocks and watches. Brass castings are often used to make valves and pipe fittings. The explosion-proof crescent wrench for fire hydrants commonly used in ships is made of brass and aluminum.