People use "bronze" and "brass" interchangeably but they're different alloy families. Brass is copper + zinc (yellow, cheap, machinable). Bronze is copper + tin or copper + aluminum (gold to red, corrosion-resistant, stronger). Picking wrong affects cost, appearance, and service life.
The strict metallurgy:
Brass: copper + zinc. Yellow color. Easy to machine. Common grades:
Bronze: copper + tin (traditional) or copper + aluminum (aluminum bronze). Reddish-gold color. More corrosion-resistant than brass. Common grades:
Common misuse: people say "brass" when they mean "bronze" (and vice versa). In a spec, always use the exact UNS C-number.
| Property | Brass C36000 | Bearing Bronze C93200 | Aluminum Bronze C95400 |
|---|---|---|---|
| Tensile strength | 360 MPa | 240 MPa | 620 MPa |
| Yield strength | 310 MPa | 110 MPa | 275 MPa |
| Elongation | 20% | 15% | 12% |
| Hardness (Brinell) | 90 HB | 70 HB | 180 HB |
| Machinability rating | 100% (baseline) | 70% | 60% |
| Corrosion resistance | Fair (attacked by ammonia, sea water) | Good | Excellent (best in class) |
| Wear resistance | Fair | Excellent | Excellent |
| Cost (per kg) | $10-12 | $15-20 | $18-25 |
| Color | Bright yellow-gold | Red-bronze | Red-bronze with slight silver tint |
Plumbing fittings, valves, connectors. Best-in-class machinability (baseline of the rating scale). Fast cycle times, excellent surface finish.
Door hardware, lamps, jewelry. Bright yellow color. Polishable to mirror finish.
Good electrical conductivity, formability, cost. Standard for terminals and connectors.
Exactly what the name suggests. Spring-back and formability optimized for casing production.
Best saltwater corrosion resistance of any copper alloy. Used in ship propellers, marine pumps, valves, hardware. Combined with stainless, forms long-lasting marine assemblies.
Industrial standard for plain bearings. Lead content provides self-lubrication. Softer than aluminum bronze but wear-optimized.
Low-friction sliding against steel. Used in gearing where steel-on-steel would wear too fast.
Brass fittings in some water chemistry (high chloride, high oxygen) experience dezincification — zinc leaches out leaving a porous copper matrix. Bronze has no zinc (or very little) and doesn't dezincify.
Handles dilute acids, many chemicals better than brass. For process pumps and valves in chemical plants.
In certain water chemistry (high chloride content, stagnant flow, elevated temperature), brass can fail via dezincification:
Solutions:
For international plumbing codes (UK, Australia, many EU countries), dezincification-resistant (DR) brass is required. For US plumbing, DR brass is growing but not universal.
Email [email protected] with your application. For plumbing, specify the water environment. For marine, bronze only. For decorative, brass. We'll confirm the right grade.
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