What is Gunmetal (Red Brass)
Gunmetal, occasionally called ‘red brass’ in the US, is an alloy made from copper, zinc, and tin [1, 2]. Aside from its basic constituents, modified forms may have nickel and lead, which are classified as ‘nickel gunmetal’ and ‘leaded gunmetal’ . Because of good strength, corrosion resistance, and ease of casting, gunmetal has been widely used for thousands of years .
The chemical composition of gunmetal can be varied [1, 2]. Here we have shared the components of Admiralty Gunmetal:
Modified gunmetal may contain up to 7 percent lead and up to 6 percent nickel  while the copper alloy C90300 or G Bronze comprises 8 percent tin and 4 percent zinc .
Properties and Characteristics of Gunmetal
|Color/appearance||Gray with bluish or purplish tinge |
|Density||8.72 X 103 kg/m3 |
|State of matter at room temperature||Solid |
|Electric resistivity||15.6 X 10-8 Ohm-m |
|Modulus of elasticity||103 GPa |
|Thermal expansion (at 20 °C)||19.8 X 10-6 °C-1 |
|Thermal conductivity||74.8 W/mK |
|Specific heat capacity||377 J/kgK |
|Yield strength||152 MPa |
|Tensile strength||310 MPa |
|Fatigue strength||90 MPa |
|Liquidus temperature||999 °C |
|Solidus temperature||854 °C |
|Hardness||75 HB(500) |
- Intricate, pressure-tight castings like pipe fittings, valves, and pumps are made from gunmetal .
- It is now commonly used for making statues .
- Bearings, where speeds and loads are moderate, are manufactured from gunmetal and used in machinery [7, 8].
The scrap price is about $1.8 per pound of gunmetal 
- Gunmetal – Diracdelta.co.uk
- Gunmetals – Copperalliance.org.uk
- Red Brass/Gunmetals – Copper.org
- C90300 (SAE 620) Tin Bronze – Anchorbronze.com
- Gunmetal – Dictionary.com
- Cast copper alloy C90500 (Gun Metal) – Substech.com
- Gunmetal (CuSnZnPb) – Oecam.eu
- Gunmetals – Copperalliance.eu
- Red Brass Scrap Price – Scrapmonster.com