Gunmetal bronze, also known as leaded gunmetal or red bronze, is an alloy that exhibits excellent machinability, corrosion resistance (especially to seawater), and thermal properties. It is commonly used for bushings, bearings, and other components exposed to harsh environments.

Here’s a summary of the key properties and specifications you provided:

Chemical Composition (wt%)

• Copper (Cu): Remainder
• Tin (Sn): 1.5 – 3.5%
• Lead (Pb): 4.0 – 9.0%
• Zinc (Zn): 7.0 – 11.0%
• Phosphorus (P): ≤ 0.1%
• Iron (Fe): ≤ 1.2%
• Nickel (Ni): ≤ 2.0%
• Antimony (Sb): ≤ 0.3%
• Sulfur (S): ≤ 0.1%

Mechanical Properties

• Tensile Strength (Rm): 200 MPa
• Yield Point (Rp0.2): 80 MPa
• Elongation (A5): 12%
• Hardness (HBW 10-1000): 65

Physical Properties

• Density: 8.7 kg/dm³
• Specific Heat: 0.370 J/(g·K)
• Thermal Expansion: 18.0 × 10⁻⁶ K⁻¹
• Thermal Conductivity: 71 W/(m·K)
• Electrical Conductivity: 8.5 MS/m

Standards

• EN 1982: CC490K
• ASTM B505: C84400

Applications

This alloy is typically used for:

• Bearings and bushings in marine and industrial applications
• Components exposed to seawater due to its corrosion resistance
• Machinery parts requiring good machinability and moderate strength

Given its ability to resist seawater corrosion, it is particularly beneficial for use in marine environments, including ship repair and engine spare parts, where reliability and longevity are crucial.