Brass vs Bronze

Copper + zinc.
Copper + tin.
Different properties.

Brass is copper-zinc alloy. Bronze is primarily copper-tin alloy. Despite both being copper-based and gold-appearing, they have distinctly different mechanical, corrosion, and application characteristics.

Get a Quote DFM guide

01 · At a glance

Side-by-side summary.

Option A

Brass (Copper-Zinc)

Copper + 5-40% zinc. Yellow-gold color. Excellent machinability (C360 is the standard free-cutting brass). Widely used for fittings, valves, decorative. Cheaper than bronze.

Option B

Bronze (Copper-Tin)

Copper + 5-20% tin, sometimes with aluminum, nickel, silicon. Reddish-gold color. Better saltwater corrosion resistance. Standard for bearings, marine, ship propellers.

02 · Detailed comparison

Feature-by-feature breakdown.

Attribute	Brass (C360 free-cut)	Bronze (C932 bearing)
Composition	Cu-35Zn-3Pb	Cu-7Sn-3Zn-7Pb
Density (g/cc)	8.49	8.93
Tensile strength (MPa)	338	241
Yield strength (MPa)	207	124
Machinability rating	100 (best of brass)	90
Saltwater corrosion	Poor (dezincification)	Excellent
Ambient appearance	Yellow-gold	Reddish-gold
Friction/wear	Average	Excellent (self-lubricating)
Cost per kg	$6-10	$12-25
Electrical conductivity	28% IACS	12% IACS
Typical applications	Fittings, valves, decorative	Bearings, marine, propellers

03 · Decision guide

When to choose each.

Choose Brass (Copper-Zinc) when:

Indoor plumbing fittings, hose bibs
Decorative hardware (door handles, hinges)
Electrical connectors (good conductivity)
Precision machined components (free-cutting)
Musical instruments (brass section)
Cost-sensitive applications

Choose Bronze (Copper-Tin) when:

Bearings and bushings (self-lubricating)
Marine hardware (saltwater corrosion)
Ship propellers (cavitation resistance)
Sculpture and architectural (durability)
Chemical processing valves
High-wear sliding applications

FAQ

Common questions.

Brass contains zinc which selectively dissolves in saltwater — called dezincification. Zinc leaches out leaving weakened spongy copper structure. Over time, brass parts weaken and fail. Bronze (no zinc, or small amount with tin protection) doesn't suffer dezincification. For any saltwater or chloride environment, specify bronze. For naval brass (C464 with tin added), some dezincification resistance but still inferior to bronze.

Naval brass (C464) is technically brass (zinc > tin in composition) but with 0.5-1.5% tin added for improved saltwater resistance. Middle ground: better than regular brass in saltwater, inferior to true bronze. Used in: above-waterline marine fittings, where cost matters but some saltwater exposure expected. Below-waterline or immersed: specify true bronze.

Bronze has excellent properties for plain bearings: (1) Lower friction against steel than brass. (2) Better wear resistance under load. (3) Tin content provides solid-lubricant effect. (4) Retains strength at elevated temperature. Leaded bearing bronze (C932, C954): lead content (5-15%) acts as additional solid lubricant. For bushings, gears, worm gear wheels running against steel, bearing bronze is standard.

Brass: bright yellow-gold, polishes to mirror finish, tarnishes over time. Bronze: reddish-gold with warmer tone, develops patina over time (often desirable for sculpture). For jewelry and bright decorative: brass. For sculpture and architectural: bronze. For aged/weathered appearance: bronze. Both can be lacquered to prevent tarnishing.

C360 brass contains 3% lead which acts as chip breaker during machining. Lead particles act as cutting fluid, produce clean short chips, enable fast cutting speeds. Machinability rating 100 (best reference) means: cuts 2-3× faster than steel, finer finish, longer tool life. Issue: lead is regulated (RoHS, environmental concerns). Alternatives: C370 (similar with less lead), bismuth brass (lead-free), silicon brass.

Brass generally cheaper due to zinc (cheap) vs tin (expensive). Free-cut brass C360: $6-10/kg. Bearing bronze C932: $12-25/kg. Aluminum bronze C954: $15-30/kg. Phosphor bronze: $15-25/kg. For cost-driven non-corrosion applications: brass. For marine or bearing applications: bronze worth premium. For decorative: either, specify based on appearance.