C4641

C4641 is a naval brass alloy, a 60:40 copper-zinc alloy enriched with about 1% tin to improve corrosion resistance, particularly against dezincification. It is a two-phase alpha-beta brass with higher strength and lower ductility compared to single-phase alpha brasses, often used for structural and forged applications in marine environments.

Chemical Composition

• Copper (Cu): 59.00 – 62.00%

• Tin (Sn): 0.50 – 1.00%

• Lead (Pb): Up to 0.50%

• Iron (Fe): Up to 0.20%

• Zinc (Zn): Balance (Remainder)

Mechanical Properties (Typical, JIS C4641, Temper BD)

• Tensile Strength (UTS): Minimum 375 MPa

• Elongation (min): 10%

• Hardness: Varies by temper and shape; commonly between 30 – 60 HRB

Physical Properties

• Melting Point: Solidus 1630°F (888°C), Liquidus 1650°F (899°C)

• Density: 8.41 g/cm³

• Electrical Conductivity: ~26% IACS at 68°F

• Thermal Conductivity: 67 BTU/(ft²·hr·°F)

• Coefficient of Thermal Expansion: 11.8 x 10⁻⁶/°F

Fabrication and Applications

• Excellent soldering and brazing capability

• Good oxyacetylene welding and spot welding; limited suitability for arc welding

• Fair cold workability and excellent hot forgeability (forge rating 90)

• Typical uses include marine hardware, pump shafts, valves, and structural components in seawater environments