C3712

C3712 is a leaded free-machining 60/40 alpha-beta brass alloy widely used for engraved plates, plaques, builder’s hardware, and gears. It has good machinability due to the lead content and maintains moderate strength and corrosion resistance. It is not recommended for acid-etched work, which requires single-phase alpha brasses.

Chemical Composition

• Copper (Cu): 58.00 – 62.00%

• Lead (Pb): 0.25 – 1.20%

• Tin + Iron (Sn + Fe): Up to 0.80%

• Zinc (Zn): Balance

Mechanical Properties (Typical, temper R410)

• Tensile Strength: Minimum 315 MPa (varies by size and shape)

• Elongation: Minimum 15%

• Hardness: Varies with size and temper

Physical Properties

• Melting Point: Liquidus ~1650°F (899°C), Solidus ~1630°F (887°C)

• Density: 8.41 g/cm³

• Electrical Conductivity: 27% IACS at 68°F

• Thermal Conductivity: 69 BTU/(ft²·hr·°F)

• Coefficient of Thermal Expansion: 11.6 x 10⁻⁶ per °F

Fabrication Properties

• Excellent soldering

• Good brazing

• Welding is generally not recommended except for butt welding

• Fair cold workability, excellent hot workability

• Machinability rating around 70%