What Is Brass
Brass is an alloy of copper and zinc. By varying the copper-zinc ratio and adding small amounts of tin, lead, aluminum, silicon, or arsenic, manufacturers produce materials with a wide range of strength, color, corrosion resistance, and machinability. Brass is used in hardware, plumbing fixtures, electrical connectors, musical instruments, and industrial machinery, making it one of the most versatile alloy families in engineering.
Composition and the Role of Each Element
| Element | Role |
|---|---|
| Copper | Base metal; provides conductivity, corrosion resistance, and color |
| Zinc | Adds strength and lowers melting point |
| Lead | Improves machinability; restricted in potable-water grades |
| Tin | Improves corrosion resistance, especially in seawater |
| Aluminum | Strengthens and improves oxidation resistance |
| Arsenic | Suppresses dezincification in water service |
Brass Alloy Families
Alpha brass, below 37 percent zinc: soft, malleable, suited to cold forming, musical instruments, and decorative work.
Alpha-beta brass, 37 to 45 percent zinc: stronger, suited to hot working, valve stems, and marine fittings.
Beta brass, above 45 percent zinc: high strength, lower ductility, used for locks and fittings.
Cartridge brass C26000, 70/30: deep drawing, ammunition, plumbing.
Naval brass C46400: tin-bearing, for seawater hardware.
Free-cutting brass C36000: lead-bearing, for high-speed machining.
Red brass C23000 and yellow brass C26800: plumbing and decorative service.
DZR brass: arsenic-bearing grades that resist dezincification in aggressive water.
Mechanical Properties
| Alloy | Tensile Strength (MPa) | Yield Strength (MPa) | Hardness (HB) |
|---|---|---|---|
| Admiralty C44300 | 240-310 | 110-180 | 65-100 |
| Cartridge C26000 | 380-550 | 170-310 | 60-100 |
| Muntz C28000 | 290-460 | 130-310 | 55-95 |
| Naval C46400 | 290-440 | 120-280 | 60-100 |
| Red C23000 | 240-380 | 90-200 | 30-80 |
Brass versus Copper and Bronze
Copper is a pure metal with the highest electrical and thermal conductivity of the three. Brass is a copper-zinc alloy with superior machinability and corrosion resistance at lower cost. Bronze is a copper-tin alloy with high strength and wear resistance, ideal for bearings and bushings. The choice depends on conductivity, strength, and fabrication requirements.
Applications
Bearings, bushings, valves, fittings, and pumps.
Springs, fasteners, and heat exchanger tubes and fins.
Electrical connectors, terminals, and switchgear.
Fire sprinkler components and instrumentation.
Decorative hardware, trim, and musical instruments.
Frequently Asked Questions
Q: What is brass made of?
A: Brass is primarily copper and zinc, with optional additions such as tin, lead, aluminum, or arsenic.
Q: What is the difference between brass and bronze?
A: Brass is a copper-zinc alloy; bronze is a copper-tin alloy, generally stronger and more wear resistant.
Q: Which brass is best for plumbing?
A: Red brass C23000 and dezincification-resistant grades are common for water service.
Q: Is brass corrosion resistant?
A: Yes, brass resists atmospheric and fresh water corrosion, though dezincification can occur in aggressive water.
Q: Why is lead added to brass?
A: Lead improves machinability by breaking chips, at the cost of restricting potable-water use.
Q: Is brass recyclable?
A: Yes, brass is fully recyclable without loss of performance.
