# UNS C63000 Nickel Aluminium Bronze Forgings, Rings, Discs and Bars

ASTM B150 · ASTM B124 · ASTM B171 · AMS 4640 · CW307G / CuAl10Ni5Fe4 · W.Nr. 2.0966 · BS CA104 · GB QAl10-4-4

Technical data page maintained by Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China. Last reviewed 18 September 2026.

Canonical HTML version: https://www.steelforgepieces.com/Alloy-Steel/UNS-C63000.html

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UNS C63000 is a wrought nickel aluminium bronze of nominally 82% copper, 10% aluminium, 5% nickel and 3% iron. It is the strongest aluminium bronze in general commercial use. Specified minimum tensile strength runs from 690 to 760 MPa (100 to 110 ksi) according to section size, and the alloy holds that strength in seawater, brackish water and dilute non-oxidising acids. Nickel raises the strength of the base aluminium bronze without costing it ductility, toughness or corrosion resistance.

Material is bought against ASTM B150 for rod, bar and shapes, ASTM B124 for forging rod, bar and shapes, ASTM B171 for condenser and heat exchanger plate, and AMS 4640, the aerospace specification behind most landing gear bushings. Nearest international equivalents are EN CW307G / CuAl10Ni5Fe4, W.Nr. 2.0966, BS 2874 CA104 and Chinese GB QAl10-4-4.

Jiangyin Jiangnan Metal Co., Ltd. forges C63000 to ASTM B124 and AMS 4640 as open-die rings, discs, hollow bars, sleeves, shafts and tube sheets, supplied with EN 10204 3.1 or 3.2 certification. Enquiries to sales@steelforgepieces.com or +86 189 2135 9659.

## Key facts at a glance

- Alloy family: wrought copper-aluminium alloy (aluminium bronze), nickel-bearing grade. It is not a steel.
- Density: 7.58 g/cm3 (0.274 lb/in3), roughly 4% lighter than carbon steel
- Tensile strength (AMS 4640): 690 MPa (100 ksi) min. at 76 to 127 mm section, rising to 760 MPa (110 ksi) min. below 25 mm
- Hardness: 187 to 248 HB according to size and temper
- Hot working range: 788 to 927 °C (1450 to 1700 °F). Forgeability rating 75.
- Annealing range: 593 to 704 °C (1100 to 1300 °F)
- Melting range: solidus 1035 °C, liquidus 1054 °C (1895 to 1930 °F)
- Magnetic response: essentially non-magnetic, and non-sparking on impact
- Common tempers: 020 hot forged and annealed, HR50 drawn and stress relieved, TQ50 quench hardened and temper annealed

## What is UNS C63000?

UNS C63000, also written C630, CDA 630 or "AMS 4640 bronze", is a wrought nickel aluminium bronze. It sits in the copper-aluminium family, where 9 to 11% aluminium forms a tough, self-repairing oxide film on the surface. What separates it from a plain aluminium bronze such as C61400 is the deliberate addition of 4.0 to 5.5% nickel with 2.0 to 4.0% iron. Nickel stabilises the microstructure and suppresses the brittle gamma-2 phase that embrittles aluminium bronzes at high aluminium content. Iron refines the grain and raises hardness.

The alloy therefore reaches steel-like strength, commonly 110 ksi or 760 MPa tensile, while staying resistant to seawater corrosion, non-magnetic, non-sparking and very resistant to galling against steel. Aircraft landing gear bushings, ship propeller hardware, valve stems and heavy hydraulic bushings for earth-moving equipment are usually cut from this one grade for that reason.

C63000 is a wrought alloy. It is extruded, hot forged or hot rolled, never cast. The cast counterpart of similar chemistry is C95500 or C95800 to ASTM B148, a separate specification with different properties. The two should not be substituted for each other without a technical review.

## Chemical composition of UNS C63000

Limits are the requirements of ASTM B150/B150M, ASTM B124/B124M and AMS 4640. Single values are maximums. Copper plus silver plus the sum of the named elements must total 99.5% minimum.

| Element | Minimum | Maximum | Role in the alloy |
| --- | --- | --- | --- |
| Copper (Cu + Ag) | Remainder | Remainder | Base metal, nominally about 82% |
| Aluminium (Al) | 9.00 | 11.00 | Forms the protective oxide film, primary strengthener |
| Nickel (Ni + Co) | 4.00 | 5.50 | Suppresses the brittle gamma-2 phase, raises corrosion resistance |
| Iron (Fe) | 2.00 | 4.00 | Grain refinement, hardness, wear resistance |
| Manganese (Mn) | – | 1.50 | Deoxidiser, minor strengthener |
| Silicon (Si) | – | 0.25 | Residual |
| Zinc (Zn) | – | 0.30 | Residual |
| Tin (Sn) | – | 0.20 | Residual |

Source: ASTM B150/B150M, ASTM B124/B124M and AMS 4640 chemical requirements for UNS C63000.

**Two requirements that get missed on purchase orders.** ASTM B150 and B124 both state that the iron content shall not exceed the nickel content. A mill certificate showing Fe 4.0% against Ni 4.0% complies. Fe 4.0% against Ni 3.9% does not. Separately, where the product is intended for later welding and the purchaser specifies this, chromium, cadmium and zirconium are each held to 0.05% max and zinc is tightened to 0.05% max. If that applies to your part, state the welding intent on the order.

## Mechanical properties of UNS C63000

Required minimum properties drop as section size increases. Larger cross-sections cool more slowly and cannot be cold worked through. AMS 4640 carries the table most often quoted, reproduced below for HR50 drawn and stress relieved material and for TQ50 temper annealed material.

| Size range (rounds, hexagons, octagons) | Tensile strength, min. | Yield strength, min. (0.5% extension under load) | Elongation in 4D, min. | Hardness |
| --- | --- | --- | --- | --- |
| Up to 1 in (25 mm) incl. | 110 ksi / 760 MPa | 68 ksi / 470 MPa | 10% | 201-248 HB |
| Over 1 to 2 in (25-51 mm) incl. | 110 ksi / 760 MPa | 60 ksi / 415 MPa | 10% | 201-248 HB |
| Over 2 to 3 in (51-76 mm) incl. | 105 ksi / 725 MPa | 55 ksi / 380 MPa | 10% | 187-241 HB |
| Over 3 to 5 in (76-127 mm) incl. | 100 ksi / 690 MPa | 50 ksi / 345 MPa | 10% | 187-241 HB |

Source: AMS 4640 mechanical property requirements for C63000. Hardness measured at 3000 kg load. Elongation gauge length is four times the diameter.

Typical measured properties, which are not specification minimums:

| Property | Metric | Imperial |
| --- | --- | --- |
| Tensile strength, typical | 760 MPa | 110,000 psi |
| Yield strength, typical | 470 MPa | 68,200 psi |
| Modulus of elasticity in tension | 121 GPa | 17,500 ksi |
| Modulus of rigidity (shear modulus) | 44 GPa | 6,400 ksi |
| Poisson's ratio | 0.34 | 0.34 |
| Fatigue strength (10^8 cycles, reverse bending) | 255 MPa | 37,000 psi |
| Hardness | about 94 HRB | about 94 HRB |

Source: Copper Development Association typical property data for C63000. Design calculations should use the specification minimums above, not these typical values.

## Temper designations on a C63000 certificate

| Temper | Process | Typical product |
| --- | --- | --- |
| 020 | Hot forged and annealed | Open-die forgings, rings, discs, shaped forgings |
| HR50 | Drawn (cold worked) and stress relieved | Bar and rod up to about 76 mm (3 in) diameter |
| TQ50 | Quench hardened and temper annealed | Bar over 76 mm (3 in), forgings and shapes needing uniform properties through a heavy section |

The distinction has commercial consequences. AMS 4640 adds a mandatory thermal stress-relief cycle after cold drawing; ASTM B150 does not. Bar bought to ASTM B150 alone can retain drawing stresses and move during precision machining. Bar bought to AMS 4640 is dimensionally stable. For close-tolerance bushings, put AMS 4640 on the purchase order.

## Physical and thermal properties

| Property | Metric | Imperial |
| --- | --- | --- |
| Density / specific gravity | 7.58 g/cm3 at 20 °C | 0.274 lb/in3 at 68 °F |
| Melting point, solidus | 1035 °C | 1895 °F |
| Melting point, liquidus | 1054 °C | 1930 °F |
| Electrical conductivity | 0.041 MS/cm at 20 °C | 7% IACS at 68 °F |
| Thermal conductivity | 39.1 W/(m·K) at 20 °C | 22.6 Btu·ft/(hr·ft2·°F) at 68 °F |
| Coefficient of thermal expansion | 16.2 x 10^-6 /°C (20-300 °C) | 9.0 x 10^-6 /°F (68-572 °F) |
| Specific heat capacity | 377 J/(kg·K) at 20 °C | 0.09 Btu/(lb·°F) at 68 °F |

Source: Copper Development Association physical property data for C63000. The expansion figures are the matched pair 9.0 x 10^-6 /°F = 16.2 x 10^-6 /°C. Some supplier sheets print 15.5 x 10^-6 /°C, which does not convert back to the published imperial value.

## Forging, welding and machining C63000

### Hot forging

C63000 carries a forgeability rating of 75 against free-cutting brass at 100, with a recommended hot working range of 788 to 927 °C (1450 to 1700 °F). Below roughly 750 °C the alloy work-hardens sharply and surface cracking becomes likely. Above about 950 °C the grain coarsens and low-melting constituents begin to melt. Holding the furnace window and the finishing temperature is what decides whether the forging comes out sound, and the margin is narrower than it is for carbon or low-alloy steel.

Annealing is carried out at 593 to 704 °C (1100 to 1300 °F). Cold working capacity is poor, so do not plan on cold sizing or straightening finished C63000 parts.

### Welding and joining

| Process | Suitability |
| --- | --- |
| Gas shielded arc welding (GTAW / GMAW) | Good, the preferred route |
| Coated metal arc welding (SMAW) | Good |
| Spot, seam and butt welding | Good |
| Brazing | Fair |
| Soldering | Not recommended |
| Oxyacetylene welding | Not recommended, the aluminium oxide film cannot be managed |

Where the part will be welded after delivery, tell the mill at enquiry stage so the tightened residual limits in ASTM B150 and B124 are applied to the heat.

### Machining

Machinability is rated 30 on the scale where free-cutting brass C36000 equals 100. In practice it cuts more like a tough stainless than like brass. Use a rigid setup, sharp positive-rake carbide, moderate surface speed, a generous feed that stays under the work-hardened layer, and flood coolant. Chips come off stringy. Allow a finishing pass after heavy roughing to clear the work-hardened skin.

## Corrosion and wear behaviour

C63000 performs well in several environments that defeat other high-strength alloys.

- Seawater and brackish water. Excellent general corrosion, erosion and cavitation resistance. This is why it is standard for propeller hardware, pump wear rings and offshore firewater fittings.
- Dilute sulphuric and hydrochloric acid, and non-oxidising acids. Good resistance. Avoid oxidising acids such as nitric, and avoid ammonia.
- Stress corrosion cracking. Aluminium bronzes are not subject to the ammoniacal SCC that affects brasses, which is a decisive advantage over high-strength brass in marine service.
- Galling and adhesive wear. Outstanding anti-galling behaviour against hardened steel shafts. This property is the reason for its dominance in landing gear and hydraulic bushings.
- Elevated temperature. Retains a high proportion of room-temperature strength well above the point at which aluminium alloys have softened.
- Non-sparking. Accepted for tools and fittings used in flammable atmospheres.

The main caution is selective phase corrosion, or de-aluminification, in stagnant, low-flow or hot chlorinated seawater. Correct nickel content and proper heat treatment are the defence against it, which is a further reason to buy against a certified chemistry rather than a nominal one.

## International equivalent grades for C63000

Near equivalents rather than drop-in substitutes, since composition bands, tempers and test requirements differ between standards. Confirm against the governing specification on the drawing before substituting.

| Region | Standard | Designation |
| --- | --- | --- |
| USA | ASTM B150 / B150M, ASME SB-150 | C63000, rod, bar and shapes |
| USA | ASTM B124 / B124M, ASME SB-124 | C63000, forging rod, bar and shapes |
| USA | ASTM B171 / B171M, ASME SB-171 | C63000, plate for condensers and heat exchangers |
| USA | AMS 4640 (current revision AMS 4640H) | C63000, aerospace bar, rod, shapes, tube and forgings |
| USA | SAE J461 / J463 | CA630 |
| USA | Military and Federal | MIL-B-16166, MIL-B-24059, QQ-C-465B (superseded) |
| Europe | EN 12163 / 12165 / 12167 / 12420 / 1653 | CW307G |
| Europe | EN chemical designation | CuAl10Ni5Fe4 |
| Europe | DIN 17665 / 17672 / 17678, Werkstoff-Nr. | CuAl10Ni5Fe4, 2.0966 |
| Europe | NF A51-116 / NF L14-705 (France) | CuAl10Ni5Fe4, UA10N |
| UK | BS 2872 / BS 2874 | CA104 |
| UK | Defence Standard | DEF STAN 02-833 / NES 833, DTD 197A |
| China | GB/T 4423, GB 4429, GB/T 13808 | QAl10-4-4 (CuAl10Fe4Ni4) |

Cross-references compiled from ASTM, SAE/AMS, EN, DIN, BS and GB designation tables. Chemistry bands vary slightly between standards, so equivalence here is for identification only.

## C63000 vs C63200 vs C95800, which nickel aluminium bronze?

These three grades are regularly confused at enquiry stage. C63000 is the high-strength wrought grade. C63200 gives up some strength for better weldability and higher ductility. C95800 is the cast grade, produced by a different route altogether.

| Property | C63000 | C63200 | C95800 |
| --- | --- | --- | --- |
| Form | Wrought (forged or extruded) | Wrought (forged or extruded) | Cast |
| Main specification | ASTM B150 / B124 / B171, AMS 4640 | ASTM B150 / B124 / B171 | ASTM B148, MIL-B-24480 |
| Aluminium | 9.0-11.0% | 8.7-9.5% | 8.5-9.5% |
| Nickel | 4.0-5.5% | 4.0-4.8% | 4.0-5.0% |
| Iron | 2.0-4.0% | 3.5-4.3% | 3.5-4.5% |
| Manganese | 1.5% max | 1.2-2.0% | 0.8-1.5% |
| Tensile strength, spec. minimum | 690-760 MPa (AMS 4640, by size) | 621 MPa (ASTM B150) | 586 MPa (ASTM B148) |
| Elongation, spec. minimum | 10% | 15-18% | 15% |
| Weldability | Good | Better, preferred for welded fabrications | Good |
| Best suited to | Landing gear bushings, valve stems, high-load bearings, shafts | Welded marine fabrications, fasteners, thick sections | Propellers, pump casings, valve bodies, complex shapes |

Composition bands per ASTM B150 (C63000, C63200) and ASTM B148 / B505 (C95800). Strength and elongation figures are specification minimums, which is what a design calculation should use. Note the trade-off in the table: C63000 is the strongest of the three, but C63200 has to reach 15 to 18% elongation against C63000's 10%, which is why it is preferred for welded fabrications and thick sections.

## Where UNS C63000 is used

**Aerospace.** Landing gear bushings and bearings, strut bearings, main pistons, trunnion bearings, control bushes and other high-load wear components. This is the classic AMS 4640 application, and anti-galling behaviour against hardened steel pins is usually the deciding property.

**Marine and offshore.** Ship propeller hardware and propeller nuts, propeller and pump shafts, bolts and nuts, hull fittings, seawater pump wear rings and wear plates, valve stems and seats, and firefighting equipment on offshore platforms.

**Power generation and desalination.** Condenser tube sheets, tube plates, baffles and support plates, heat exchanger flanges and headers, shafting and welded piping systems. This is the field covered by ASTM B171 plate.

**Oil, gas and heavy industry.** Valve balls, guides and seats, pump parts and pump shafts, hydraulic bushings for earth-moving equipment, gears, cams, plunger tips, forming and drawing dies, structural members, tanks, and non-sparking safety tooling and welding clamps.

Product forms supplied: forged rings, seamless rolled rings, discs and blanks, round bar, hollow bar, sleeves and bushings, tube sheets, baffles, flanges, shafts, blocks, shaped forgings.

## C63000 open-die forging capability

Jiangyin Jiangnan Metal Co., Ltd. has forged since 1997 at Zhouzhuang Town, Jiangyin, Jiangsu Province, inside the Yangtze River Delta forging cluster and about two hours by road from the ports of Shanghai and Ningbo. C63000 is forged to ASTM B124, ASTM B150 and AMS 4640 in the 020 and TQ50 tempers.

| Item | Scope |
| --- | --- |
| Product forms | Open-die forged rings, seamless rolled rings, discs, blocks, round bar, hollow bar, sleeves, bushings, shafts, flanges, tube sheets and shaped forgings |
| Specifications | ASTM B124, ASTM B150, ASTM B171, AMS 4640, and the EN, DIN, BS and GB equivalents listed above |
| Tempers | 020 hot forged and annealed, TQ50 quench hardened and temper annealed |
| Minimum order | 10 kg, with no minimum piece count. Single prototype pieces are accepted. |
| Lead time | 20 to 60 days from order confirmation, according to size, temper and testing scope |
| Heat treatment | Annealing and quench-and-temper carried out in-house on calibrated, chart-recorded furnaces |
| Machining | Rough machining, proof machining and finish machining to customer drawing |
| Approvals | Class society approvals from CCS, BV, DNV, LR and NK |

Plant capability across all materials:

| Item | Capacity |
| --- | --- |
| Forging presses | 6,300 t, 4,000 t and 2,000 t |
| Ring mills | 6 m, 3 m and 1 m |
| Maximum piece weight | 30,000 kg (30 t) |
| Maximum ring outside diameter | 6,000 mm |
| Maximum heat size | 60 tonnes |
| Workforce | 460 staff, including 9 senior engineers, 32 intermediate engineers and 140 technicians |

The figures above are the capacity of the plant across all materials it forges. C63000 parts are normally forged well below these limits, and copper alloys behave differently from steel on a press of this size. Send the drawing with the enquiry and the achievable size for your part will be confirmed with the quotation.

## Quality control and documentation

Every C63000 forging leaves the plant with the documentation an inspection department expects. A small deviation in nickel changes the corrosion behaviour of this alloy, so the mill certificate matters here as much as the dimensions do.

- Chemical analysis by optical emission spectrometry on every heat, reported against the ASTM B150, B124 and AMS 4640 limits, including the clause that iron shall not exceed nickel
- Positive material identification on finished parts on request
- Tensile and yield testing with elongation in 4D, taken from prolongations representative of the forging
- Brinell hardness at 3000 kg load, reported against the size-appropriate AMS 4640 band
- Ultrasonic testing to ASTM B594 or a customer-nominated acceptance class
- Dye penetrant inspection where surface integrity is critical
- Dimensional report against the customer drawing
- EN 10204 3.1 certification as standard, with 3.2 certification and third-party witness inspection on request. The works holds class society approvals from CCS, BV, DNV, LR and NK.
- Full traceability from heat number through forging, heat treatment and machining

## Frequently asked questions about UNS C63000

**Is UNS C63000 a steel or a bronze?**
C63000 is a bronze, not a steel. It is a wrought copper-aluminium alloy, a nickel aluminium bronze, of roughly 82% copper with 10% aluminium, 5% nickel and 3% iron. It has no iron matrix and behaves nothing like steel in corrosion, machining or welding. Supplier websites often file it under a general alloy heading, which is where the confusion starts.

**What is the difference between C63000 and AMS 4640?**
They are not alternatives. AMS 4640 is the aerospace specification that governs C63000 material. Bar can be bought to ASTM B150 alone, or to AMS 4640, which imposes the same chemistry but adds a mandatory stress-relief cycle after cold drawing and tighter property control by size. Specify AMS 4640 where dimensional stability during precision machining matters.

**What is the tensile strength of C63000?**
Minimum tensile strength under AMS 4640 is 110 ksi (760 MPa) for sizes up to 2 inches (51 mm), 105 ksi (725 MPa) over 2 to 3 inches, and 100 ksi (690 MPa) over 3 to 5 inches. Minimum yield strength at 0.5% extension under load runs from 68 ksi (470 MPa) down to 50 ksi (345 MPa) across the same size bands, with 10% minimum elongation in 4D throughout.

**What is the European equivalent of C63000?**
The closest European equivalent is CW307G, chemically designated CuAl10Ni5Fe4, covered by EN 12163, EN 12165, EN 12167, EN 12420 and EN 1653. The German material number is W.Nr. 2.0966 under DIN 17665 and DIN 17672. The British equivalent is BS 2874 CA104 and the Chinese equivalent is GB QAl10-4-4. These are near equivalents for identification rather than certified drop-in substitutes.

**Can C63000 be welded?**
Yes. Gas shielded arc welding (GTAW and GMAW) and coated metal arc welding both give good results, as do spot, seam and butt welding. Brazing is fair. Soldering and oxyacetylene welding are not recommended, because the tenacious aluminium oxide film cannot be controlled with those processes. Where the part will be welded, tell the mill at enquiry so the tightened residual element limits in ASTM B150 and B124 are applied.

**At what temperature is C63000 forged?**
The recommended hot working range is 788 to 927 °C (1450 to 1700 °F), with a forgeability rating of 75. Annealing is carried out at 593 to 704 °C (1100 to 1300 °F). Cold working capacity is poor, so forming should be completed hot. The window is narrower than it is for steel, and holding it determines whether the forging is sound.

**Is C63000 magnetic?**
C63000 is essentially non-magnetic. Its iron and nickel content give it a slight magnetic permeability, typically just above 1.0, which is negligible for most applications but worth confirming if the part will sit near sensitive instrumentation such as a compass or magnetometer. It is also non-sparking on impact, so it is accepted for tools used in flammable atmospheres.

**Does C63000 resist seawater?**
Yes, and seawater service is its primary application. C63000 offers excellent general corrosion, erosion and cavitation resistance in seawater and brackish water, and it is not subject to the ammoniacal stress corrosion cracking that affects high-strength brasses. The one caution is selective phase corrosion in stagnant, low-flow or hot chlorinated seawater, which correct nickel content and proper heat treatment guard against.

**Can you supply a single prototype C63000 forging?**
Yes. The minimum order is 10 kg with no minimum piece count, so a single prototype ring, disc or sleeve is accepted. Lead time runs 20 to 60 days from order confirmation according to size, temper and testing scope. Prototype pieces carry the same EN 10204 3.1 certification and the same testing as a production order.

## How to order C63000 forgings

Send a drawing, or the six items below, and you will have a firm quotation.

1. Grade and specification. For example "UNS C63000 to ASTM B124" or "C63000 to AMS 4640H"
2. Temper required. 020, HR50 or TQ50
3. Form and dimensions. Ring, disc, bar, sleeve or shaped forging, with OD, ID, length or thickness, and whether rough or finish machined
4. Quantity and delivery date
5. Testing and certification. EN 10204 3.1 or 3.2, UT class, PMI, third-party witness
6. Service conditions. In particular whether the part will be welded, or will see stagnant seawater, so that the right chemistry controls are applied

## Contact

Jiangyin Jiangnan Metal Co., Ltd.
Open-Die Forging Factory

- Factory address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone, WhatsApp, WeChat: +86 189 2135 9659
- Email: sales@steelforgepieces.com
- Website: https://www.steelforgepieces.com/

## References

- ASTM B150/B150M, Standard Specification for Aluminum Bronze Rod, Bar, and Shapes
- ASTM B124/B124M, Standard Specification for Copper and Copper Alloy Forging Rod, Bar, and Shapes
- ASTM B171/B171M, Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers
- SAE AMS 4640, Nickel-Aluminum Bronze Bars, Rods, Shapes, Tubes and Forgings, current revision AMS 4640H
- Copper Development Association, C63000 alloy data

This page is maintained as reference material for engineers and buyers specifying C63000. Data is reproduced from the standards cited above and is believed correct at the date of last review. It is offered for guidance and does not replace the governing specification on your drawing. Corrections are welcome at sales@steelforgepieces.com.