CW302G

CW302G is a copper-aluminium alloy with the chemical designation CuAl7Si2. It is recognised for its combination of strength, corrosion resistance, and moderate ductility, with a density of about 7.7 g/cm³.

Chemical Composition

• Aluminium (Al): 6.3 – 7.6%

• Silicon (Si): 1.5 – 2.2%

• Iron (Fe): Up to 0.3%

• Manganese (Mn): Up to 0.2%

• Nickel (Ni): Up to 0.2%

• Copper (Cu): Balance (remainder)

• Other elements: Pb, Zn, Sn, total maximum of around 0.2%

Mechanical Properties

• Tensile Strength: 500 – 600 MPa (depending on temper R500 and R600)

• Proof Strength (0.2% offset): 250 – 350 MPa

• Elongation: Minimum 12 – 20%

• Brinell Hardness: 120 (R500) to 140 (R600+ temper)

Physical Properties

• Density: 7.7 g/cm³

• Thermal Conductivity: About 45 W/m·K

• Electrical Resistivity: About 0.13 µΩ·m

• Coefficient of Linear Expansion: About 17 x 10⁻⁶ /°C

Applications

• Marine hardware and propeller components

• Pump and valve components

• Wear parts and structural components requiring corrosion resistance

• Chemical and heat exchanger equipment

Fabrication and Welding

• Fair machinability (rating around 40%)

• Hot working: Suitable range 705 – 925°C

• Welding: Suitable with proper controls (gas shielded arc, resistance welding)