Brass (Cu+Zn)
Brass is a copper-zinc alloy with zinc content typically ranging from 5–45%. Known for its golden color, excellent machinability, acoustic properties, and corrosion resistance, brass is widely used in plumbing fittings, musical instruments, ammunition casings, and decorative hardware.
Properties
- Density
- 8,400–8,730 kg/m³
- Melting Point
- 900–940 °C
- Boiling Point
- 1,100 °C (Zn evaporation)
- Thermal Conductivity
- 109–159 W/(m·K)
- Electrical Resistivity
- 3.9–7.0 × 10⁻⁸ Ω·m
- Tensile Strength
- 300–700 MPa
- Yield Strength
- 100–450 MPa
- Hardness
- 55–200 HB
- Elongation
- 5–65%
- Crystal Structure
- FCC (α) / BCC (β)
Common Grades
- CuZn37 (C27200): Common yellow brass, 63% Cu. Good formability, electrical components, architectural trim.
- CuZn39Pb3 (C38500): Free-cutting brass, the most machinable copper alloy. Fittings, valves, screw-machine parts.
- CuZn30 (C26000): Cartridge brass, 70% Cu. Excellent deep-drawing capability. Ammunition, radiator cores.
- CuZn36Pb2As: Dezincification-resistant brass. Potable water fittings, marine hardware.
Applications
- Plumbing: Valves, fittings, taps, connectors, compression fittings
- Electrical: Terminals, connectors, switch components, lamp fittings
- Music: Trumpets, trombones, saxophones, bells, cymbals
- Decorative: Door handles, locks, hinges, nameplates, architectural hardware
FAQ
What is the difference between brass and bronze?
Brass is primarily a copper-zinc alloy, while bronze is a copper-tin alloy. Brass is typically golden-yellow with excellent machinability, while bronze is reddish-brown with superior wear resistance and marine corrosion resistance. Bronze is generally harder and more expensive.
Is brass safe for drinking water fittings?
Yes, but only dezincification-resistant (DR) grades that comply with drinking water regulations. Modern standards require low-lead brass (below 0.25% Pb in many regions) to prevent lead leaching. Look for EN 12164/12168 compliant grades.
What is dezincification and how is it prevented?
Dezincification is selective corrosion where zinc dissolves from brass, leaving a weak porous copper structure. It occurs in brasses with >15% Zn exposed to stagnant or aggressive water. Prevention: use arsenic-inhibited grades (CuZn36Pb2As), reduce zinc content, or select bronze/copper-nickel alternatives.