Material Insight
Brass vs. Bronze: Composition, Properties, and Machining Comparison for Engineers
By YKWiki Engineering Team · Published 2026-06-03
Not the Same Metal
Brass is primarily copper + zinc (5-45% Zn). Bronze is primarily copper + tin (1-12% Sn), though commercial bronze designations can include aluminum bronzes (Cu-Al), silicon bronzes (Cu-Si), and manganese bronzes (Cu-Zn-Mn, which are technically brasses). The confusion is understandable — the term 'bronze' is used loosely in commercial naming.
Properties Comparison
| Property | Brass (C26000) | Phosphor Bronze (C51000) | Aluminum Bronze (C95400) |
|---|---|---|---|
| Tensile (MPa) | 300-650 | 340-690 | 585-655 |
| Yield (MPa) | 75-420 | 130-550 | 240-275 |
| Machinability | Excellent (30-50%) | Fair (20%) | Good (50-60%) |
| Corrosion | Good (dezincification risk) | Excellent (marine) | Excellent (marine, wear) |
Selection Guide
Choose brass when: Machinability is primary (free-cutting brass C36000 is the standard for high-speed screw machine parts), electrical conductivity matters (brass ~28% IACS vs bronze ~15%), cost is the main constraint (brass ~30-50% cheaper than bronze). Choose bronze when: The part operates in seawater (aluminum bronze or phosphor bronze), wear resistance is critical (bearing bronze), fatigue strength matters (phosphor bronze for springs), or the part requires the aesthetic of traditional bronze (statues, architectural).
References & Standards
- ASTM International. Steel & Alloy Standards. astm.org
- International Organization for Standardization (ISO). iso.org
- National Institute of Standards and Technology (NIST). Materials Data. nist.gov
- ASM International. Materials Information Society. asminternational.org
- World Steel Association. Steel Statistical Yearbook. worldsteel.org