Overview
Brass is an alloy primarily composed of copper and zinc, known for its bright yellow
color and excellent machinability. It is a versatile material that exhibits good
corrosion resistance, electrical conductivity, and aesthetic appeal. Brass is widely
used in various applications, including plumbing, electrical connectors, and decorative
items.
Grades and Specifications
Brass is available in various grades, each tailored for specific applications. The most
common grades include:
- C26000 (Cartridge Brass): Contains approximately 70% copper and 30%
zinc. Known for excellent cold workability and corrosion resistance.
- C28000 (Commercial Bronze): Contains around 90% copper, offering
superior corrosion resistance and strength.
- C36000 (Free-Cutting Brass): Contains approximately 63% copper and
37% zinc, known for its excellent machinability.
- C46200 (Naval Brass): Contains copper, zinc, and small amounts of
tin, providing excellent corrosion resistance in marine environments.
Specifications:
- ASTM: B36, B283, B455, B543
- ASME: SB36, SB283, SB455
Chemical Composition
The chemical composition of brass can vary based on the specific grade. Here is a general
breakdown for C36000 (Free-Cutting Brass):
| Element |
Composition (%) |
| Copper (Cu) |
61.5 – 63.5 |
| Zinc (Zn) |
35.0 – 37.0 |
| Lead (Pb) |
2.5 – 3.5 |
| Iron (Fe) |
0.05 max |
| Other Elements |
Balance |
Mechanical Properties
Brass exhibits a good balance of strength, ductility, and hardness. Typical mechanical
properties for C36000 brass are:
- Tensile Strength: 550 MPa (approx.)
- Yield Strength: 310 MPa (approx.)
- Elongation: 20% (approx.)
- Hardness: 90 HRB (Rockwell B hardness)
Applications
Brass is used in a wide range of industries due to its desirable properties:
- Plumbing: Fittings, valves, faucets, and connectors due to its
corrosion resistance and ease of machining.
- Electrical: Connectors, terminals, and switches because of its
excellent electrical conductivity.
- Musical Instruments: Horns and other instruments for their acoustic
properties and aesthetic appeal.
- Automotive: Components such as radiator cores, carburetors, and
electrical connectors.
- Decorative Items: Jewelry, fixtures, and ornamental designs due to
its attractive appearance.
Corrosion Resistance
Brass is generally resistant to corrosion in many environments, particularly in
non-oxidizing atmospheres. However, it can be susceptible to dezincification in certain
conditions, leading to a loss of zinc and potentially weakening the material. To
mitigate this, certain grades, such as Naval Brass (C46200), are
designed for better corrosion resistance in marine environments.
Workability and Fabrication
Brass is known for its excellent machinability, making it easy to cut, shape, and form
into complex parts. Common fabrication methods include:
- Casting: Ideal for producing intricate shapes.
- Machining: Easily machined into various components, thanks to its
free-cutting properties.
- Welding: Can be welded, but specific precautions should be taken to
avoid hot cracking.