Naval brass C46400 – UNS C46400
Alpha-beta brass with tin for marine use
Brass with ≈ 60% Cu, 39% Zn and 0.5 – 1% Sn, where tin improves seawater corrosion resistance and dezincification resistance compared with common brass. Good strength, excellent hot formability and good forgeability. Used in shafts, marine hardware, condenser tubesheets and forged parts.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | C46400 |
| W.Nr./EN | CW719R – CuZn39Sn1 (approx.) |
| DIN | 2.0530 – CuZn38Sn1 (approx.)* |
| JIS | C4640 |
| Trade names | Naval brass, Tobin bronze* |
| Others | AMS 4611, 4612; QQ-B-639; SAE J461/J463 |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM B21/B21M (bar, rod and shapes) |
| Forging | ASTM B124/B124M, B283/B283M |
| Plate | ASTM B171/B171M (condenser tubesheets) |
| Bar | ASTM F467 / F468 (nuts and bolts) |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7407.21.10 | 7407.21 | 7407.21.9000 | 7407 21 10 |
| Hot-rolled bar | 7407.21.10 | 7407.21 | 7407.21.9000 | 7407 21 10 |
| Plate (> 10 mm, width ≥ 600 mm) | 7409.29.00 | 7409.29 | 7409.29.0010 | 7409 29 00 |
| Flange and fitting | 7412.20.00 | 7412.20 | 7412.20.0090 | 7412 20 00 |
Tariff class: copper-zinc alloy (brass) (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM B21 (UNS C46400)
| Element | Range (%) |
|---|---|
| Cu | 59.0 – 62.0 |
| Sn | 0.50 – 1.0 |
| Pb | ≤ 0.20 |
| Fe | ≤ 0.10 |
| Zn | balance (Cu + named elements ≥ 99.6) |
Mechanical properties
typical, bar (CDA)
| Property | Value |
|---|---|
| Annealed (O60): tensile strength | ≈ 395 MPa |
| Annealed (O60): yield strength (0.5%) | ≈ 170 MPa |
| Annealed (O60): elongation | ≈ 47% |
| Quarter hard (H01, Ø 25 mm): tensile strength | ≈ 475 MPa |
| Quarter hard (H01, Ø 25 mm): yield strength (0.5%) | ≈ 315 MPa |
| Quarter hard (H01, Ø 25 mm): elongation | ≈ 27% |
| Hardness (H01) | ≈ 75 – 80 HRB |
Typical physical properties
| Property | Value |
|---|---|
| Density | 8.41 g/cm³ |
| Melting range | 888 – 899 °C |
| Modulus of elasticity | 103 GPa |
| Electrical conductivity | ≈ 26% IACS |
| Thermal conductivity (20 °C) | ≈ 116 W/m·K |
| Thermal expansion (20–300 °C) | 21.2 µm/m·K |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Usual use up to ≈ 200 °C*. In stagnant or hot seawater it may suffer dezincification; for those conditions, prefer copper-nickel or aluminum bronze. |
| Heat treatment | Annealing at ≈ 425 – 595 °C. Hot working between ≈ 650 and 815 °C. Stress relief recommended after cold forming to reduce the risk of stress corrosion cracking*. Not hardenable by heat treatment. |
| Welding | Excellent brazing and soft soldering; good oxyacetylene, spot and butt welding. TIG/MIG welding only fair because of zinc evaporation; covered electrode not recommended. |
| Machining | Medium machinability (≈ 30, C36000 = 100). Continuous chip; sharp tool and chip breaker help. |
Typical applications
- Propeller shafts and rods for vessels
- Marine hardware, nuts and bolts (ASTM F467/F468)
- Condenser and heat exchanger tubesheets
- Hot-forged parts for valves and fittings
- Rings, bushings and structural components in marine environments
Alternatives: Nickel-aluminum bronze C63000 for higher strength and seawater corrosion resistance; 90/10 copper-nickel C70600 for piping and exchangers; common brass only in dry environments.
Frequently asked questions
What is the chemical composition of Naval brass C46400?
Per ASTM B21 (UNS C46400): Cu 59.0 – 62.0; Sn 0.50 – 1.0; Pb ≤ 0.20; Fe ≤ 0.10; Zn balance (Cu + named elements ≥ 99.6).
Which standards cover Naval brass C46400?
Bar: ASTM B21/B21M (bar, rod and shapes). Forging: ASTM B124/B124M, B283/B283M. Plate: ASTM B171/B171M (condenser tubesheets). Bar: ASTM F467 / F468 (nuts and bolts).
Up to what temperature can Naval brass C46400 be used?
Usual use up to ≈ 200 °C*. In stagnant or hot seawater it may suffer dezincification; for those conditions, prefer copper-nickel or aluminum bronze.
Which materials can replace Naval brass C46400?
Nickel-aluminum bronze C63000 for higher strength and seawater corrosion resistance; 90/10 copper-nickel C70600 for piping and exchangers; common brass only in dry environments.
