Wrought nickel aluminium bronze · Open-die forgings

2.0966 Forgings (CuAl10Ni5Fe4, CW307G, UNS C63000, CA104, AMS 4640)

• 2.0966
• CuAl10Ni5Fe4
• EN CW307G
• UNS C63000
• CA104
• AMS 4640
• ASTM B150 / B124 / B171
• NES 833 / DEF STAN 02-833
• SAE J463 CA630
• ISO CuAl10Ni5Fe4

Published 18 May 2016 · Last updated 8 September 2026 · Reviewed by the Jiangyin Jiangnan Metal metallurgical engineering team

Werkstoff

2.0966EN CW307G

UNS

C63000CA104 · AMS 4640

Base metal

Copper~78–85% Cu, balance

Density

7.6g/cm³ · 0.275 lb/in³

Tensile, typical

700–740MPa · 102–107 ksi

Proof Rp0.2

≥330MPa · 48 ksi

Elongation A5

10–15% minimum

Hardness

180–195HB typical

Forge from

900°C, finish above 830 °C

Temper anneal

675°C ±15, 2–6 h, air cool

What 2.0966 forged products can you buy?

Jiangyin Jiangnan Metal produces CuAl10Ni5Fe4 by three routes, chosen by geometry and order size. Open-die forging covers shafts, blocks, discs and heavy sections. Seamless ring rolling produces rings, wear rings and bearing races, and is the cheapest route for anything with a hole through the middle. Upset forging handles short, large-section hubs, flanges and valve bodies. Nickel aluminium bronze costs several times as much per kilogram as carbon steel and machines at roughly a third of the rate, so near-net shape pays for itself quickly on this grade.

Size ranges are the plant envelope across all grades. Copper alloy orders normally sit inside it; confirm your specific part before designing to the limits.

Every form above can be supplied temper annealed at 675 °C for seawater service, rough or finish machined to your drawing, and certified to EN 10204 3.1 or 3.2. Send the finished drawing rather than a billet size: on this alloy, choosing the right forging route usually saves more than any other decision on the order. The worked example below gives the numbers.

What is 2.0966, and why does it exist?

Nickel aluminium bronze was developed to solve a problem that neither brass nor plain bronze could handle: high strength combined with survival in fast-moving seawater. Aluminium bronzes get their corrosion resistance from a tenacious aluminium oxide film rather than from a copper oxide layer, and that film re-forms almost instantly when it is stripped away by flow, sand or cavitation bubbles. Adding nickel and iron to a binary copper-aluminium alloy turns a corrosion-resistant material into a structural one.

Three properties explain nearly every specification of this grade:

• Strength without loss of toughness. Nickel at 4–6% raises tensile strength past 700 MPa while keeping ductility and impact toughness that a heat-treated steel of similar strength would not match. That combination is why the alloy is used for aircraft landing-gear bushings and trunnion bearings, where a brittle failure is not survivable.
• Erosion, cavitation and seawater resistance. The oxide film tolerates flow velocities that erode copper-nickel alloys, and the alloy resists cavitation damage on propellers and pump impellers. It carries no zinc, so it cannot dezincify, and it is effectively immune to the ammonia stress corrosion cracking that limits high-strength brasses.
• Wear and galling resistance under load. The hard iron-and-nickel-rich kappa phases dispersed through the alpha matrix act as load-bearing particles. Against a steel counterface, 2.0966 resists galling and seizure far better than a steel-on-steel pair, which is why it dominates heavy hydraulic bushings, wear plates and gear applications.

What the alloy is not is a high-temperature material or a cheap one. Above about 300 °C its strength falls away, and continuous service is normally limited to roughly 200–250 °C. It is also poor in cold working, so any forming has to be done hot. If the duty is simply "corrosion resistance" without high load, velocity or wear, a copper-nickel alloy or a duplex stainless steel is usually cheaper and easier to fabricate.

What are the equivalents of 2.0966?

Buyers meet this one alloy under at least a dozen names, because it was standardised separately in Germany, Britain, France, the United States and by several navies. All of the designations in Table 1 describe the same nominal Cu–10Al–5Ni–4Fe chemistry, and we accept purchase orders under any of them. They are not interchangeable in their acceptance requirements: the product-form specification decides the test regime, not the chemistry.

Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published alloy specifications. Standards are cited by number only; always reference the revision in force at the contract date, and state the product-form specification rather than the chemistry alone.

What is the chemical composition of 2.0966?

There are two bands in common use and they are not identical. The European band (CW307G) is wider on iron and nickel and tighter on manganese; the North American band (C63000) is tighter on iron and nickel and puts an explicit floor under copper. A single heat can be made to satisfy both, but it has to be bought against both from the start. You cannot re-certify an EN heat into ASTM afterwards if the iron result sits at 4.6%.

Source: Jiangyin Jiangnan Metal Co., Ltd., 2.0966 forging specification, compiled from EN 12163 / 12165 / 12420 for CW307G. Older DIN editions and some mill datasheets give iron as 2.0–5.0% and manganese as 1.5% max; if a legacy DIN revision governs your order, state which one.

Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from ASTM B150/B150M and ASTM B124/B124M for Copper Alloy UNS C63000. Every heat we supply carries a ladle analysis on the mill certificate; product analysis can be added on request.

What are the mechanical properties of 2.0966?

Unlike a precipitation-hardening steel, 2.0966 has no strength/toughness ladder to choose from. What you actually specify is the product form, the ruling section and the heat-treatment condition. The figures below are published typical values for wrought material; the acceptance minima that appear on the certificate are set by the specification on your order.

Sources: EN datasheet values for CW307G; extruded-rod nominal values published by wrought aluminium bronze producers; ASTM B150 minima for C63000. ASTM minima vary with temper and diameter, so the figures shown are the commonly quoted baseline rather than a universal requirement.

Behaviour at temperature

2.0966 keeps useful strength to about 300 °C, which is high for a copper alloy but unremarkable against steel. Sustained service above roughly 250 °C is unusual, partly because strength falls and partly because the protective oxide behaves differently in hot dry air than it does in seawater. Below zero the alloy behaves well: copper alloys have a face-centred-cubic structure with no ductile-to-brittle transition, so 2.0966 keeps its toughness at cryogenic temperatures where a ferritic steel would fail. That makes it a legitimate choice for LNG valve trim and cryogenic pump wear parts.

What are the physical properties of 2.0966?

Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from published wrought nickel aluminium bronze data. Screening figures, not design allowables.

How does 2.0966 behave in seawater and other media?

The protective mechanism is an aluminium oxide film, not a copper oxide one, and that single fact explains most of the alloy’s behaviour. The film is thin, hard, adherent and re-forms in milliseconds when it is damaged, provided oxygen is available. Where oxygen is present and water is moving, 2.0966 performs extremely well. Where water is stagnant, deaerated or polluted with sulphides, the film cannot repair and the advantage disappears.

Two mechanisms that limit other copper alloys do not apply here. There is no meaningful zinc content, so dezincification is impossible. And unlike high-strength brasses, nickel aluminium bronze is not susceptible to ammonia stress corrosion cracking. The failure mode that does apply is selective phase corrosion of retained beta phase, and that is a processing question rather than a design one. The next section deals with it.

On galvanic compatibility, 2.0966 sits between carbon steel and the passive alloys. Coupled to carbon steel or cast iron it is the cathode and will accelerate attack on the steel. Coupled to stainless steel, titanium or graphite composites it becomes the anode; in a seawater system with a large stainless surface and a small bronze fitting, the bronze will suffer. Keep the area ratio favourable, insulate where practical, and include the bronze surfaces in the cathodic protection scheme.

Retained beta phase: the one heat treatment that decides corrosion life

This is the most important section on the page, and the thing most often missing from a 2.0966 purchase order.

At forging temperature, nickel aluminium bronze is largely beta phase. On cooling, beta is supposed to decompose into a stable structure of soft alpha matrix with hard kappa precipitates dispersed through it. That decomposition takes time. If a forging is cooled quickly from above roughly 900 °C, some beta survives to room temperature as retained beta. A water quench, an air blast or simply a thin section on a cold day is enough to cause it.

Retained beta is aluminium-rich, and it is anodic to the alpha matrix around it. In seawater it corrodes preferentially. The mechanism is called selective phase corrosion or dealuminification, and it is insidious: the component keeps its shape and its outward appearance while the beta network dissolves from the inside, leaving porous, weak copper behind. Parts have failed in service looking externally sound. It is the nickel-aluminium-bronze equivalent of dezincification in brass, and it is the reason naval standards for this alloy family exist at all.

What this means on your purchase order

• State the treatment explicitly. “Temper anneal 675 °C ±15 °C, 2–6 h at temperature, air cool, per DEF STAN 02-833”. A specification that says only “annealed” or “stress relieved” does not get you this.
• Require it recorded on the certificate, with the actual temperature and soak time, not just a tick box.
• Re-apply it after welding. The heat-affected zone reaches beta temperature and cools fast against a cold parent section, so a welded 2.0966 seawater part that is not re-annealed has a ring of retained beta around every weld, exactly where the stress is.
• Ask for a metallographic check on critical parts. A section examined at 100× to 500× will show whether the beta has gone. On naval and offshore work this is normally a specified acceptance test, not an option.
• It is not needed for dry duty. A landing-gear bushing, a gear or a non-sparking tool sees no electrolyte. Specifying the anneal there simply costs strength for nothing.

2.0966 against the alloys it competes with

Most enquiries come down to one of four comparisons: a stronger or a more weldable nickel aluminium bronze, a cast equivalent, a nickel alloy, or a duplex stainless steel.

Comparative figures compiled by Jiangyin Jiangnan Metal Co., Ltd. from published typical properties. Use for screening only; the design authority owns the selection.

Three questions that usually settle it

1. Is there sliding contact or galling risk? If yes, the bronze is worth paying for and neither duplex nor a nickel alloy will do the job. Bushings, wear rings and gears go to 2.0966 almost by default.
2. Will the part be welded into a large fabrication? If yes, look hard at C63200, which has a wider margin against retained beta and is easier to weld without post-weld treatment. This is why naval seawater systems often specify it in preference.
3. Is a casting acceptable? For a complex pump casing or propeller, C95800 cast nickel aluminium bronze gives most of the corrosion performance at lower cost. Forge only where you need the wrought structure’s soundness and directional strength: shafts, bushings, highly stressed rings.

How is 2.0966 forged and heat treated?

Nickel aluminium bronze forges well but not freely. Hot forgeability is rated 75 against forging brass at 100, and the working window is narrower than the published range suggests. Cold working is rated poor and should not be planned into the route at all.

1. Raw materialCertified CW307G / C63000 forging stock to EN 12165 or ASTM B124. Heat number traced, ladle analysis verified against the governing band before the billet is cut.
2. Soak at 900 °CHeld long enough to bring the entire section to temperature, not just the surface. The published range for C63000 is 788–927 °C (1450–1700 °F); we work the upper part of it and control the finish rather than the start.
3. Forge, finishing above 830 °CReduction of 4:1 or better to break down the cast structure. Reheat rather than continue to deform a cooling billet. Below about 800 °C the alloy loses hot ductility quickly and edge cracking follows.
4. Ring roll or upset as requiredRadial-axial ring mills for anything annular; upsetting for short heavy hubs and flanges. Route chosen at quotation stage from the finished drawing.
5. Controlled coolAir cool from the forging heat. A fast quench from above 900 °C is what creates the retained beta problem, so heavy sections are cooled deliberately rather than blown.
6. Temper anneal 675 °C ±15 °C2 to 6 hours at temperature scaled to ruling section, then air cool. Mandatory for seawater duty per DEF STAN 02-833 / NES 833; omitted on dry-service parts where the strength matters more.
7. MachineRough or finish to drawing. Carbide tooling, moderate speeds, positive depth of cut, flood coolant.
8. Test and examineTensile, hardness, chemistry, metallography for retained beta where specified. Ultrasonic examination to ASTM B594 or EN 10228-3; penetrant to ASTM E165.
9. CertifyEN 10204 3.1 as standard, 3.2 with third-party witness. Marked with heat number, specification, condition and drawing number, then preserved and packed.

Welding, machining and forming 2.0966

Welding

Weldability is good by gas shielded arc processes and poor or impossible by everything else, and the reason is the same oxide film that protects the alloy in service. It melts far above the base metal and prevents wetting and fusion unless it is displaced by an inert-gas arc.

Source: published joining ratings for Copper Alloy UNS C63000, compiled by Jiangyin Jiangnan Metal Co., Ltd.

Practical points: clean back to bright metal immediately before welding, because the film re-forms in minutes. Preheat is normally unnecessary and can be harmful on heavy sections. Keep interpass temperature moderate. And on any seawater part, re-apply the 675 °C temper anneal after welding. The heat-affected zone reaches beta temperature and cools quickly against cold parent metal, which is precisely the condition that produces retained beta at the joint.

Machining

The machinability rating is 30 where C36000 free-cutting brass is 100; some sources quote 20. That puts 2.0966 well below brass and bronze bearing alloys and well above the nickel superalloys. The hard kappa particles that carry the wear resistance also abrade the cutting edge.

• Carbide or coated carbide tooling; HSS only for light work
• Rigid setup, moderate surface speed, positive depth of cut, never letting the tool rub
• Flood coolant, directed at the cutting edge
• Chips are tough and stringy rather than free-breaking; plan chip control into the setup
• On a machined component the metal removal often costs more than the forging, so ask for a near-net shape

Cold forming

Rated poor. Bending, spinning and cold heading are not realistic routes on this alloy in any meaningful section. Design for hot forming and machining instead, and treat any drawing that assumes cold work as an error to be queried before the order is placed.

How do 2.0966 parts fail, and how do you prevent it?

What can Jiangyin Jiangnan Metal forge in 2.0966?

2.0966 is a made-to-order grade for us. We buy the heat against your specification rather than pulling from stock, which is why the drawing, the governing specification and the required certificate all matter at enquiry stage rather than after the order.

Rolled ring OD

200–2,500mm plant envelope

Disc / tube sheet

≤ 1,800mm diameter

Shaft length

≤ 8,000mm

Bar diameter

25–500mm

Single piece

≤ 8,000kg plant envelope

Ring wall, min

30mm

Lead time

8–14weeks typical

Quotation

24hours from drawing

The company employs approximately 460 people, including 9 senior engineers and 32 intermediate engineers. Alongside 2.0966 we forge carbon, alloy and tool steels, the precipitation-hardening and duplex stainless families, and the nickel and cobalt high-temperature alloys.

Which standards and certificates apply to 2.0966 forgings?

Quality management is certified to ISO 9001:2015. Third-party witness certificates are issued through the inspection body you nominate: Lloyd’s Register, DNV, Bureau Veritas, ABS, TÜV or SGS. Customers keep an unrestricted right to witness any production stage, including chemistry, forging, heat treatment and mechanical testing.

How do you specify a 2.0966 forging order?

1. Name the material genericallyWrite 2.0966 / CuAl10Ni5Fe4 / CW307G, and add UNS C63000 if the project uses both systems. Do not rely on a supplier trade name.
2. Cite the product-form specificationEN 12420 for forgings, ASTM B124 for forgings and forging stock, AMS 4640 for aerospace. ASTM B150 is rod, bar and shapes and does not cover a forging. The chemistry alone is not a specification.
3. Require the temper anneal for wet duty“Temper anneal 675 °C ±15 °C, 2–6 h at temperature, air cool, per DEF STAN 02-833”, recorded on the certificate. Omit it deliberately for dry service, do not leave it silent.
4. State the ruling section and test positionGive the greatest thickness heat must travel through, and say whether tensile tests are longitudinal or transverse and whether they come from the part, a prolongation or a separately forged test bar.
5. Define NDE and acceptance class“UT per EN 10228-3, quality class 3” or “UT per ASTM B594 with acceptance to the purchase order”. An unqualified “ultrasonic test” is not a specification.
6. State any magnetic permeability limitThe alloy is weakly magnetic. If there is a ceiling, give the number and require it measured.
7. Name the certificate typeEN 10204 3.1 as standard, or 3.2 with a named third-party inspection body.
8. Give quantity, date, Incoterm and destinationQuantity drives the melt. Small orders are consolidated onto a larger heat, which affects both price and schedule.

Drawing callout you can copy

MATERIAL:      2.0966 / CuAl10Ni5Fe4 / EN CW307G
               (dual certify to UNS C63000 if required)
SPECIFICATION: EN 12420 forgings  (or ASTM B124 / AMS 4640)
               revision per contract date
CHEMISTRY:     Al 9.0-11.0, Ni 4.0-5.5 incl. Co, Fe 3.0-4.0,
               Mn 1.0 max, Si 0.20 max, Zn 0.30 max, Pb 0.02 max,
               Cu balance.  Report full ladle analysis.
CONDITION:     Hot forged 900 to 830 deg C, air cooled, then
               TEMPER ANNEAL 675 deg C +/-15 deg C, 2-6 h at
               temperature, air cool, per DEF STAN 02-833.
               Actual temperature and soak time to be recorded.
MECHANICAL:    Rm ___ MPa min, Rp0.2 ___ MPa min, A5 ___ % min,
               stated AGAINST RULING SECTION ___ mm.
               Test pieces: longitudinal / transverse, from
               part / prolongation / separate test bar.
STRUCTURE:     Metallographic examination for retained beta
               phase, 100x to 500x, on ___ pieces per heat.
PERMEABILITY:  Relative permeability ___ max, measured
               (state only if the application requires it)
NDE:           UT per EN 10228-3 quality class 3 (or ASTM B594)
               PT per ASTM E165, Type I Method C
CERTIFICATE:   EN 10204 3.1  (3.2 with third-party witness if
               stated on the PO)
MARKING:       Heat number, specification, condition and drawing
               number, low-stress stamped or vibro-etched

Seven mistakes buyers make with 2.0966

1. Leaving the temper anneal unstated on a seawater part. The single most expensive omission on this grade. “Annealed” or “stress relieved” does not get you the 675 °C cycle, and selective phase corrosion does not show up until the part is in service.
2. Copying a composition table with nickel shown as “Including Co”. That is a truncated ASTM footnote, not a value. The figure is 4.0–5.5% for C63000 and 4.0–6.0% for CW307G.
3. Citing ASTM B150 for a forging. B150 covers rod, bar and shapes. Forgings and forging stock are B124.
4. Assuming EN and ASTM are interchangeable. The iron band differs by a full percentage point. A heat that meets CW307G at Fe 4.6% fails C63000. Decide dual certification before the melt.
5. Specifying bar properties for a heavy forging. 700 MPa is a small-section figure. State minima against the ruling section or the order will be queried.
6. Assuming the alloy is non-magnetic. It is weakly ferromagnetic. If permeability matters, test it.
7. Buying a solid block and machining a ring out of it. On a priced-per-kilogram alloy that machines at a third of steel’s rate, ring rolling routinely halves the purchased weight. See the worked example.

Ask for a 2.0966 / CuAl10Ni5Fe4 quotation

Where is 2.0966 used?

Two worked examples

Example 1: why a rolled ring is cheaper than a machined disc

Given. A finished wear ring, 620 mm OD × 480 mm ID × 210 mm high, in 2.0966.

Method. Net volume = π/4 × (0.620² − 0.480²) × 0.210 = 0.0254 m³. At 7,600 kg/m³ that is about 193 kg finished. Rolled as a seamless ring with 25% stock, the forging is roughly 241 kg. Machined from a solid forged disc of the same outside diameter and height, the input billet is about 479 kg, so you would buy, forge and then cut away some 286 kg of nickel aluminium bronze.

Result. Ring rolling roughly halves the purchased weight on this geometry. On an alloy priced per kilogram that also machines at about a third of the rate of steel, the saving compounds: less metal bought and fewer hours removing it. This is why we ask for the finished drawing rather than a billet size.

Example 2: choosing between 2.0966 and C63200 for a welded seawater manifold

Given. A fabricated seawater manifold, 40 mm wall, several hundred millimetres of circumferential weld per joint, 20-year design life, moderate mechanical stress, class-approved.

Assessment. On strength alone 2.0966 wins comfortably, roughly 700 MPa against 620–690 MPa. But strength is not the controlling factor here: the controlling factor is what happens in the heat-affected zone of every weld. 2.0966’s higher aluminium content puts it closer to the composition where retained beta forms readily, and each weld would need a full post-weld temper anneal of the whole fabrication to be defensible, which is awkward and expensive on a large assembly. C63200 sits at a lower aluminium level with a wider margin against retained beta, which is why naval seawater specifications frequently prefer it for welded work.

Decision. Specify C63200 for the welded manifold and keep 2.0966 for the shafts, bushings and wear rings inside it, where the parts are machined from solid, see no welding, and need the strength and wear resistance. Mixing the two grades in one seawater system is normal practice and raises no galvanic concern, because they are metallurgically almost the same alloy.

Glossary

2.0966 frequently asked questions

References

1. CEN, EN 12420: Copper and copper alloy forgings; EN 12163: Rod for general purposes; EN 12165: Wrought and unwrought forging stock; EN 12167: Profiles and rectangular bar; EN 1653: Plate, sheet and circles for boilers and pressure vessels. All list CuAl10Ni5Fe4 as CW307G.
2. ASTM International, B124/B124M: Copper and copper alloy forging rod, bar and shapes; B150/B150M: Aluminum bronze rod, bar and shapes; B171/B171M: Copper alloy plate and sheet for pressure vessels, condensers and heat exchangers. Copper Alloy UNS No. C63000.
3. SAE International, AMS 4640: Aluminium bronze bar, rod, shapes, tube and forgings, 10Al–5Ni–3Fe; SAE J463: Wrought copper and copper alloys, CA630.
4. UK Ministry of Defence, DEF STAN 02-833 / NES 833: Nickel aluminium bronze, requirements including the temper-anneal condition for seawater service.
5. BSI, BS 2874: Copper and copper alloy rods and sections, designation CA104.
6. DIN, DIN 17665, DIN 17672 and DIN 17678 (1983), Werkstoff 2.0966. Superseded by the EN series but still cited on legacy drawings.
7. Copper Development Association, Aluminium bronze alloys technical data and the CDA alloy database entry for C63000. Machinability, forgeability, joining ratings and hot-working temperature range.
8. Wrought aluminium bronze producers’ technical datasheets for CuAl10Ni5Fe4 / 2.0966 extruded rod. Nominal mechanical and physical property values quoted in Tables 4 and 5.
9. ASM Handbook, Volume 2, Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM International. Aluminium bronze metallurgy, kappa phase constitution and the beta phase decomposition sequence.
10. ASM Handbook, Volume 13B, Corrosion: Materials, ASM International. Selective phase corrosion of nickel aluminium bronze in seawater.
11. ASTM B594 and EN 10228-3, ultrasonic examination; ASTM E165 penetrant examination; ASTM E8/E8M and EN ISO 6892-1 tensile testing; ASTM E10 Brinell hardness.
12. CEN, EN 10204: Metallic products, types of inspection documents.

Standards are cited by number; always work to the revision in force at your contract date. Property values on this page are published typical figures for screening and are not design allowables. Test results on our certificates are independent and traceable to calibrated equipment.

About the manufacturer, and how to cite this page

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, with approximately 460 employees including 9 senior and 32 intermediate engineers. The plant runs 1 t to 9 t open-die hammers, 4,500 t and 5,000 t hydraulic presses and radial-axial ring mills up to 2,500 mm outside diameter, with in-house heat treatment, machining, mechanical testing and non-destructive examination. Alongside 2.0966 / CuAl10Ni5Fe4 we forge carbon, alloy and tool steels, the precipitation-hardening and duplex stainless families, and the nickel and cobalt high-temperature alloys. Quality management is certified to ISO 9001:2015; material is supplied with EN 10204 3.1 certification as standard and 3.2 with third-party witness on request.

Related grades and forged products

Corrosion and marine grades we forge

Product forms we forge in 2.0966