CW604N

CW604N is a low-leaded brass alloy (also designated as C33500 or CuZn37Pb0.5) optimised for good machinability, moderate strength, and effective corrosion resistance. It is commonly used for hardware items, watch backs, screw machine products, and other precision components requiring both formability and machinability.

Chemical Composition

• Copper (Cu): 62.0 – 65.0%

• Zinc (Zn): 33.8 – 37.8%

• Lead (Pb): 0.25 – 0.70%

• Iron (Fe): Up to 0.10%

• Other impurities (residuals): Up to 0.4%

Mechanical Properties

• Tensile Strength: 340 – 650 MPa

• Yield Strength: 120 – 420 MPa

• Elongation: 3 – 28% (depends on product and temper)

• Hardness: Rockwell B 53–91

Physical Properties

• Density: 8.1 g/cm³

• Melting Point: Solidus 900°C (1650°F), Liquidus 930°C (1700°F)

• Electrical Conductivity: 26% IACS

• Thermal Conductivity: 120 W/m-K (67 BTU/h-ft-°F)

• Coefficient of Thermal Expansion: 20 µm/m-K

• Specific Heat Capacity: 390 J/kg-K (0.092 BTU/lb-°F)

• Modulus of Elasticity: 100 GPa (15 x 10⁶ psi)

• Shear Modulus: 40 GPa (5.8 x 10⁶ psi)

Fabrication and Applications

• Excellent soldering and good brazing capabilities

• Good cold workability, poor hot workability

• Excellent machinability (machinability rating 60, relative to free-cutting brass)

• Used in machining, stamping, blanking, headings, watch backs, hardware, and screw machine products