Brass Properties
Brass is a copper-zinc alloy valued for its machinability, corrosion resistance, and antimicrobial properties. Learn where it excels and where it fails.
Overview
Brass is an alloy of copper and zinc (typically 60–70% copper). It is widely used for fittings, valves, plumbing components, and decorative hardware. Its excellent machinability, corrosion resistance in water, and attractive gold-like appearance make it a popular choice for fluid handling components.
Key Properties
| Property | Value |
|---|---|
| Density | 8500 kg/m³ |
| Tensile strength | 300–500 MPa |
| Melting point | 900–940°C |
| Thermal conductivity | 120 W/m·K |
| Max service temperature | 200°C |
Advantages
- Excellent machinability: Free-machining brass (C36000) is one of the easiest metals to machine — ideal for high-volume fitting and component production.
- Good corrosion resistance in water: Resists fresh water and mild atmospheres well — used extensively in plumbing.
- Antimicrobial properties: Copper alloys kill bacteria on contact — used in hospitals and food handling.
- Attractive appearance: Gold-like colour that polishes well — used in decorative and architectural hardware.
- Good casting properties: Easily cast into complex shapes for valves and fittings.
Limitations
- Dezincification: In certain waters (especially warm, soft, or acidic), zinc leaches out of the brass, leaving a porous copper structure. Use dezincification-resistant (DZR) brass for plumbing in these conditions.
- Not for high temperatures: Softens and loses strength above 200°C — not suitable for steam service.
- Ammonia stress corrosion: Brass is susceptible to stress corrosion cracking in ammonia environments.
- Not for seawater: Brass corrodes in seawater — use bronze or cupro-nickel instead.
Typical Applications
- Plumbing fittings and valves
- Water meter bodies
- Instrument fittings and connectors
- Decorative hardware
- Musical instruments
- Electrical terminals and connectors
Chemical Compatibility
| Chemical | Rating |
|---|---|
| Fresh water (neutral) | Good |
| Hot water | Fair (DZR recommended) |
| Seawater | Poor |
| Steam | Poor |
| Dilute acids | Fair |
| Alkalis | Good |
| Ammonia | Poor — stress corrosion |
How CHI can help
Ask CHI about brass properties and to determine whether it is suitable for your water service application. The CHI assistant can recommend the right material for your specific application, explain chemical compatibility, and flag when a material is unsuitable for your operating temperature or environment.