CW724R

CW724R is a silicon brass alloy with 75-77% copper and 2.7-3.5% silicon, classified under silicon red brasses. This alloy is known for excellent corrosion resistance, moderate strength, and good retention of spring properties, particularly specified for underground service lines and potable water applications.

Chemical Composition

• Copper (Cu): 75.0% - 77.0%

• Silicon (Si): 2.7% - 3.5%

• Phosphorus (P): 0.02% - 0.10%

• Lead (Pb): Max 0.10%

• Iron (Fe): Max 0.30%

• Tin (Sn): Max 0.30%

• Nickel (Ni): Max 0.20%

• Manganese (Mn): Max 0.05%

• Aluminium (Al): Max 0.05%

• Total impurities: Max 0.20%

• Zinc (Zn): Balance

Mechanical Properties (Temper R500)

• Tensile Strength (UTS): Around 500 MPa (depends on size and form)

• Proof Stress (PS): Around 450 MPa

• Minimum Elongation: 15%

• Hardness varies; the typical hardness range depends on temper and size

Physical Properties

• Melting Point (Solidus): 1510°F

• Melting Point (Liquidus): 1685°F

• Density: 8.19 lb/cu in (approx 8.3 g/cm³)

• Electrical Conductivity (% IACS at 68°F): 6.2%

• Thermal Conductivity: 15 BTU/sq ft/ft/hr/°F

• Thermal Expansion Coefficient (68-572°F): 11.2 x 10⁻⁶ /°F

• Modulus of Elasticity: 16,000 ksi

Fabrication and Uses

• Excellent soldering and brazing capabilities

• Good oxyacetylene welding, spot welding, seam welding, and butt welding suitability

• Good capacity for cold working and excellent for hot forming

• Forgeability rating: 80

• Machinability rating: 30%

• Primarily used for plumbing fittings, automotive parts, electrical and electronic components, and water supply applications