Brass vs Bronze
Brass is copper alloyed mainly with zinc; bronze is copper alloyed with tin, and by extension aluminum, silicon or manganese. Brass is yellower, cheaper, softer and, in free-machining grades like C360, the easiest metal there is to machine. Bronze is browner, harder, more wear resistant, and holds up better against seawater and sustained loads, which is why bearings, bushings, gears and marine hardware are bronze.
For machined fittings, valve bodies, decorative parts and anything that needs threads cut fast, buy brass. For a bushing, thrust washer, worm gear, propeller or a pump part in salt water, buy bronze. The representative alloys here are C360 free-machining brass and C932 bearing bronze; the families spread wider on both sides.
| Property | Brass | Bronze |
|---|---|---|
| Base alloying element | Zinc (5-40%) | Tin (typ. 5-12%); also Al, Si, Mn bronzes |
| Representative alloy | C360 (61.5 Cu, 35.5 Zn, 3 Pb) | C932 (83 Cu, 7 Sn, 7 Pb, 3 Zn) |
| Color | Bright yellow | Reddish brown |
| Density | 8.4-8.7 g/cm³ | 8.7-8.9 g/cm³ |
| Tensile (representative) | ~400 MPa (58 ksi), C360 half-hard | ~240 MPa (35 ksi), C932 cast |
| Yield (representative) | ~310 MPa (45 ksi), C360 half-hard | ~125 MPa (18 ksi), C932 cast |
| Hardness (representative) | ~75 HRB | ~65 HB |
| Machinability | Excellent; C360 is the 100% reference | Good; leaded bronzes ~70% |
| Wear / bearing use | Fair | Excellent |
| Saltwater corrosion | Fair; high-zinc grades dezincify | Good to excellent |
| Typical uses | Fittings, valves, fasteners, decorative, ammunition | Bushings, bearings, gears, marine hardware, sculpture |
Typical values for the stated conditions. Confirm against the mill certificate and your spec.
Need a Brass or Bronze part made?
- Machine shops that work with brass · 149
- Metal Casting companies that work with brass · 51
- Metal Stamping companies that work with brass · 49
- All U.S. manufacturers working with brass · 475
- Find specialty alloy suppliers
- Machine shops that work with bronze · 64
- Metal Casting companies that work with bronze · 54
- All U.S. manufacturers working with bronze · 203
Attach a drawing (PDF or STEP) or describe the part; a U.S. shop that fits quotes it.
Decision matrix
A check marks the side with the edge on that dimension.
| Dimension | Brass | Bronze |
|---|---|---|
| Machining | ✓ Excellent; C360 is the reference for machinability | Good; leaded bearing bronzes cut well, aluminum bronze is tough |
| Welding | Poor; zinc fumes and porosity, brazing and soldering preferred | ✓ Fair; aluminum and silicon bronzes weld well, tin bronzes less so |
| Forming | ✓ Excellent in low-zinc grades (C260 cartridge brass) | Fair; phosphor bronze strip forms, cast bronzes do not |
| Strength | Moderate; cold-worked bar is strongest | ✓ Ranges widely; aluminum bronze exceeds any brass |
| Corrosion resistance | Fair; dezincification in seawater and chlorinated water | ✓ Good to excellent; the marine copper alloy |
| Finishing | ✓ Polishes, plates and lacquers beautifully | Polishes and patinates; plating less common |
| Material cost | ✓ Cheaper; zinc is inexpensive | Higher; tin is costly |
| Availability | ✓ Rod, bar, sheet, tube everywhere | Cast bar and bushing stock; sheet limited to phosphor bronze |
Choose Brass when
- Screw-machine and CNC parts where cycle time is the cost
- Plumbing fittings, valve bodies, fasteners and electrical hardware
- Decorative or architectural parts that will be polished or plated
- Sheet and strip work: cartridge brass draws and stamps well
Choose Bronze when
- Bushings, thrust washers, wear plates and slow-speed bearings
- Worm gears, wheels and any part sliding under load against steel
- Marine and seawater hardware: propellers, shafts, pump parts
- High-strength copper alloy parts, where aluminum bronze rivals steel
Frequently asked questions
- What is the difference between brass and bronze?
- The main alloying element. Brass is copper plus zinc; bronze is copper plus tin, or in the wider sense aluminum, silicon or manganese. Zinc makes brass yellow, cheap and easy to machine. Tin makes bronze harder, more wear resistant and better in seawater.
- Is bronze stronger than brass?
- It depends on the grades. Cold-worked free-machining brass bar (about 310 MPa yield) is stronger than cast bearing bronze (about 125 MPa yield). Aluminum bronze, at 250-400 MPa yield and up, beats any brass. Bronze wins on hardness and wear far more consistently than on tensile strength.
- Which is better for bushings and bearings?
- Bronze, almost always. Tin and leaded tin bronzes such as C932 and C954 aluminum bronze carry load, embed debris and run against hardened steel shafts with low wear. Brass bushings work only in light-duty, low-speed service.
- Which is easier to machine?
- Brass. C360 free-machining brass is the 100% reference on the machinability scale; chips break short and tool life is very long. Leaded bearing bronzes machine well too, around 70%, while aluminum and silicon bronzes are tougher on tools.
