What Is Gun Metal?
Gun metal is a bronze alloy primarily composed of approximately 90% copper and 10% tin. It is classified as bronze due to its copper-tin composition.
Historically, gun metal was utilized for making cannon barrels, earning its name from this application. It is known for its high toughness and has other notable properties such as wear resistance, castability, corrosion resistance, and strong resistance to seawater, making it suitable for bearing applications.
There are various types of gun metal bronze, including alloys like CA401 and CA402, each offering distinct characteristics and applications.
Uses of Gun Metal
Gun metal’s excellent mechanical properties, corrosion resistance, and wear resistance make it suitable for various applications. These include valves, cocks, water pourers, bearings, gears, impellers, bushings, liquid oxygen manufacturing parts, pump casings, piston rings, water heater components, meter parts, rolling mill worm wheels, marine propellers, paper manufacturing rolls, art castings, landscape castings, plain bearings, electrical equipment parts, general machinery parts, highly elastic spring materials, ship round windows, ship parts, printing parts, chemical industry supplies, toothed washers, signs, bolts, and spring washers.
Characteristics of Gun Metal Alloys
Among the bronze alloys similar to gun metal, five notable compositions include CA401 and CA402:
- “CA401” is a copper alloy in the bronze family known as “valve metal,” used for its excellent flowability and machinability, primarily in valves.
- “CA402” offers superior pressure resistance, wear resistance, and corrosion resistance among bronze castings. It is particularly resistant to seawater, making it ideal for seawater-exposed pump parts.
- “CA403” excels in pressure resistance, wear resistance, and mechanical properties. It is highly resistant to seawater and suitable for abrasive and corrosive environments.
- “CA406,” or “ounce metal”/”leaded-red brass,” is known for its pressure resistance, wear resistance, machinability, and castability. It is one of the most commonly used copper castings.
- “CA407,” superior to “CA406,” is also known as “valve bronze for steam” and is considered for applications requiring even higher properties.