Melt
EAF followed by VOD for sulphur and gas control. ESR remelt is applied where cleanliness and directional solidification are required, typically for subsea and sour-service components.
Nickel-copper alloy · Open-die forging datasheet
NiCu30Al Forgings Monel K-500 · UNS N05500 · W.-Nr. 2.4375. Rolled rings, shafts, flanges, discs and bars forged to customer drawing in Jiangyin, China.
Grade identity
Nickel-copper alloy
- EN / DIN
- NiCu30Al
- Werkstoff
- 2.4375
- UNS
- N05500
- Trade name
- Monel K-500
- ASTM
- B865
NiCu30Al is a precipitation-hardenable nickel-copper alloy containing a minimum of 63% nickel and 27–34% copper, hardened by additions of aluminium and titanium. Its Werkstoff number is 2.4375 and its UNS number is N05500. The alloy is widely known by the trade name Monel K-500. It provides the seawater and reducing-acid resistance of Monel 400 at approximately three times the yield strength, and remains non-magnetic at ambient temperature.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. We forge NiCu30Al to customer drawing as seamless rolled rings, shafts, flanges, discs, bars, sleeves, bushings and tube sheets. Material is melted by EAF+VOD or by ESR remelt, solution treated and age hardened in our own furnaces, ultrasonically examined to EN 10228-3, SEP 1921 or ASTM A388, and certified to EN 10204 3.1 or 3.2. Hardness is controlled below the 35 HRC limit set by NACE MR0175 / ISO 15156 for sour service.
01 · Metallurgy
Composition and strengthening mechanism
NiCu30Al has the same nickel-copper matrix as Monel 400. The difference is the deliberate addition of aluminium and titanium, which makes the alloy responsive to precipitation hardening.
The matrix is a nickel-copper solid solution of approximately 63–66% nickel with the balance mainly copper. To this are added 2.2–3.5% aluminium and 0.3–1.0% titanium. During solution treatment these elements dissolve into the matrix. During ageing they precipitate as a fine coherent gamma-prime phase, Ni3(Al,Ti), distributed through the structure. The precipitate obstructs dislocation movement and raises the 0.2% proof stress from approximately 275 N/mm² in the solution-treated condition to the 655 N/mm² minimum required in the aged condition.
Corrosion resistance is essentially unchanged from Monel 400, since the matrix chemistry is unchanged. Precipitation hardening raises strength and does not improve corrosion performance. The alloy is non-magnetic at ambient temperature, its Curie point lying below room temperature, which is the reason it is specified for non-magnetic drill collars and directional survey housings. Because strength depends entirely on heat treatment, the ageing cycle is a controlled process step. Jiangyin Jiangnan Metal carries out solution treatment and ageing of NiCu30Al forgings in its own furnaces rather than subcontracting the operation.
NiCu30Al is not a high-temperature alloy. In the age-hardened condition it over-ages and loses strength above approximately 480 °C (900 °F). Service is therefore limited to ambient and moderately warm conditions such as seawater, brines, hydrofluoric acid and sour hydrocarbons. For hot service, Inconel 625 or Inconel 617 should be considered instead.
02 · Cross-reference
Equivalent grades and governing specifications
The alloy is specified under several designations depending on the standard applied. The materials are interchangeable in substance, but composition limits differ slightly between documents, so the purchase order should name one governing specification.
| System | Designation | Notes |
|---|---|---|
| EN / DIN | NiCu30Al | DIN 17743, wrought nickel-copper alloys |
| Werkstoff | 2.4375 | German material number |
| UNS | N05500 | Unified Numbering System, North America |
| Trade name | Monel K-500 | Also written Alloy K-500, K Monel |
| ASTM | B865 | Rod, bar, wire and forgings, UNS N05500 |
| AMS | AMS 4676 | Bars, forgings and rings, aerospace grade |
| US military | QQ-N-286 | Legacy US government specification |
| British | BS 3072–3076 NA18 | Sheet, strip, bar and forgings |
| Sour service | NACE MR0175 / ISO 15156 | Accepted, age hardened, 35 HRC maximum |
NiCu30Al to DIN 17743 and UNS N05500 to ASTM B865 are the same alloy family with slightly different limits on aluminium, titanium and carbon. State the governing specification on the enquiry and Jiangyin Jiangnan Metal will certify to that document.
03 · Chemistry
Chemical composition
Both columns are shown because a European drawing and an American specification are often issued for the same part. Where the two conflict, the ordered document governs.
| Element | NiCu30Al · 2.4375 | UNS N05500 · ASTM B865 |
|---|---|---|
| Ni (+ Co) | 63.0 min | 63.0 min |
| Cu | 27.0 – 34.0 | 27.0 – 33.0 |
| Al | 2.2 – 3.5 | 2.30 – 3.15 |
| Ti | 0.30 – 1.00 | 0.35 – 0.85 |
| Fe | 0.50 – 2.00 | 2.00 max |
| Mn | 1.50 max | 1.50 max |
| C | 0.20 max | 0.25 max |
| Si | 0.50 max | 0.50 max |
| S | 0.015 max | 0.010 max |
Each heat is analysed on the ladle and re-checked on the product. Product analysis is reported on the certificate in addition to the ladle analysis.
04 · Properties
Mechanical and physical properties
The values below are acceptance minima for the solution-treated and age-hardened condition. Achievable properties depend on section size. Heavy sections are agreed on the drawing before forging begins.
Mechanical properties, solution treated and aged
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | 931 N/mm² min | 135 ksi min |
| 0.2% proof stress | 655 N/mm² min | 95 ksi min |
| Elongation (A5) | 20% min | 20% min |
| Reduction of area | 35% min | 35% min |
| Hardness, sour service | 35 HRC max, limit set by NACE MR0175 / ISO 15156 | |
Physical properties
| Property | Value |
|---|---|
| Density | 8.44 g/cm³ (0.305 lb/in³) |
| Melting range | 1315 – 1350 °C (2400 – 2460 °F) |
| Modulus of elasticity | approx. 179 GPa (26 × 10&sup6; psi) |
| Thermal conductivity | approx. 17.4 W/m·K |
| Coefficient of expansion, 20–100 °C | approx. 13.7 µm/m·K |
| Electrical resistivity | approx. 61.5 µΩ·cm |
| Magnetic behaviour | Essentially non-magnetic; Curie temperature below ambient |
| Practical service ceiling | approx. 480 °C (900 °F) in the aged condition |
05 · Process route
Melting, forging and heat treatment
Open-die forge
Upsetting and drawing on hydraulic presses, or ring rolling for seamless rolled rings. Forging is completed above the recrystallisation range to close porosity and orient grain flow to the part axis.
Solution treat
Approximately 1010–1065 °C, held according to section thickness, then quenched. Aluminium and titanium return to solution and the structure is reset before ageing.
Age harden
Controlled multi-step hold between 480 °C and 595 °C with slow furnace cooling between steps. Final strength and hardness are established at this stage, including compliance with the 35 HRC sour-service limit.
Rough machine
Proof machining removes scale and the affected surface layer so that ultrasonic examination is carried out on clean metal and the part is ready for finish machining.
Test and certify
Chemical analysis, tensile testing, hardness testing and ultrasonic examination, followed by documentation to EN 10204 3.1 or 3.2. Test coupons are heat treated together with the forgings they represent.
Forging reduction ratio affects the result. An under-worked heavy section will not develop uniform properties regardless of the ageing cycle applied, so section size and reduction ratio are reviewed at quotation stage. Ageing is not equivalent to tempering. The full cycle with controlled furnace cooling occupies the greater part of a day and cannot be shortened without reducing the strength achieved.
06 · Supply range
NiCu30Al forged products and sizes
All items below are forged to customer drawing. No standard stock catalogue is held. Supply the drawing or the finished dimensions and the shape is produced from ingot or billet.
| Forged product | Typical size range |
|---|---|
| Seamless rolled rings | OD 200 – 2,500 mm · wall 30 – 500 mm · height 40 – 1,000 mm |
| Forged rings | OD 150 – 2,500 mm |
| Forged shafts and spindles | Ø 60 – 800 mm · length to 6,000 mm |
| Forged discs and disks | Ø 100 – 2,500 mm · thickness 30 – 600 mm |
| Forged round bars | Ø 50 – 800 mm |
| Forged flanges | DN 15 – DN 2000, weld neck / blind / long weld neck |
| Sleeves and bushings | OD 100 – 1,500 mm |
| Tube sheets | Ø to 2,500 mm |
| Blocks, bodies and valve parts | To drawing: stems, seat rings, gates, bonnets, bodies |
| Single piece weight | approx. 5 kg – 3,000 kg |
On NiCu30Al the practical size ceiling is normally set by nickel alloy ingot availability rather than by press capacity. Confirm heavy or large-diameter sections before committing them to a design.
07 · Where it goes
Applications for NiCu30Al forgings
NiCu30Al is selected where the corrosion resistance of Monel 400 is required but its strength is insufficient.
Marine and seawater
Propeller and pump shafts, shaft sleeves, fasteners, chains and springs in seawater and tidal waters. The alloy resists chloride-induced stress corrosion cracking that attacks austenitic stainless steels.
Oil and gas, downhole
Non-magnetic drill collars, MWD and LWD instrument sleeves, safety lift valves and associated drill collar components. Non-magnetic behaviour preserves directional survey accuracy and sour-gas resistance protects the component.
Subsea and offshore
Forged bushings, sleeves, discs and bodies for subsea and deepwater production systems, wellheads and Christmas trees, where retrieval for replacement carries high cost.
Valves
Valve stems, seat rings, gates, blocks and bodies for ball, gate, globe, check and plug valves handling brines, hydrofluoric acid and sour hydrocarbons.
Pumps and rotating equipment
Chemical pump shafts, plunger pump components, impeller hubs and eccentric shafts required to carry torque and bending loads in corrosive media.
Pressure equipment
Forged flanges, tube sheets, nozzles and shell rings for pressure vessels, air receivers and shell-and-tube heat exchangers, plus columns, towers, tanks and preheaters.
Chemical processing
Components in hydrofluoric acid service, crystalliser equipment and process modules where reducing conditions exclude stainless steels and oxidising-grade nickel alloys.
Pulp, paper and general industry
Doctor blades, scrapers, forged rolls, wheels and manifolds; also heavy machinery, industrial air compressors and generator components.
08 · Quality
Testing, inspection and certification
The scope listed as standard is included with every order. Items listed as available on request must be stated on the order, since they affect production routing and price.
Included as standard
- Chemical analysisLadle and product analysis, reported on the certificate.
- Tensile testingRoom temperature, after ageing, on coupons heat treated with the parts.
- Hardness testingReported in HRC or HBW, with sour-service limits verified where applicable.
- Ultrasonic examinationTo EN 10228-3, SEP 1921 or ASTM A388 as specified on the order.
- Dimensional inspectionAgainst the customer drawing, with a report on request.
- Material certificateEN 10204 3.1 issued by the works.
Available on request
- EN 10204 3.2Third-party witness by Lloyd's Register, BV, DNV, TUV, SGS or the customer's own inspector.
- Liquid penetrant / magnetic particlePT to ASTM E165 on machined surfaces.
- Positive material identificationPMI by XRF or OES on the finished part.
- Impact testingCharpy V-notch at ambient or low temperature.
- Grain size and microstructureMetallographic examination with photomicrographs.
- NACE MR0175 / ISO 15156Sour-service compliance statement with the hardness survey.
09 · Ordering
Information required with a NiCu30Al enquiry
The six items below allow a firm quotation to be issued without further correspondence.
- 1. Drawing or dimensionsA PDF or STEP drawing, or the finished OD, ID, height and tolerance. State whether the price is required for as-forged or rough-machined condition.
- 2. SpecificationNiCu30Al to DIN 17743, UNS N05500 to ASTM B865, AMS 4676, or the customer's own material standard.
- 3. ConditionSolution treated and aged is the normal supply condition. State if solution treated only is required.
- 4. Quantity and schedulePiece count, whether the order is a single delivery or a call-off, and the date required on site.
- 5. Test and certification scopeUT standard and acceptance class, EN 10204 3.1 or 3.2, and any PT, PMI, impact or NACE requirement.
- 6. Service conditionsMedium, temperature, pressure and whether the service is sour. These determine the ageing cycle and the hardness limits applied.
Quotations for NiCu30Al enquiries are normally issued within one working day. Where the section is unusually heavy or the specification is outside normal practice, Jiangyin Jiangnan Metal states this at enquiry stage rather than after the order is placed.
10 · Questions
NiCu30Al frequently asked questions
What is NiCu30Al?
NiCu30Al is a precipitation-hardenable nickel-copper alloy containing a minimum of 63% nickel and 27–34% copper, strengthened by additions of aluminium and titanium. It carries Werkstoff number 2.4375 and UNS number N05500, and is sold commercially under the trade name Monel K-500. Compared with the solid-solution alloy Monel 400, the aluminium and titanium form a gamma-prime precipitate during ageing which raises the yield strength by approximately three times while the corrosion behaviour in seawater and reducing conditions remains the same.
Is NiCu30Al the same as Monel K-500?
Yes. NiCu30Al is the European designation used in DIN 17743 and related EN documents for the alloy sold in the United States as Monel K-500 and specified as UNS N05500 in ASTM B865. The two names describe the same nickel-copper-aluminium-titanium alloy. Composition limits differ slightly between the European and ASTM documents, so the ordered specification should always be stated on the purchase order, and Jiangyin Jiangnan Metal certifies each forging against the specification named by the customer.
What is the difference between NiCu30Al and Monel 400?
Monel 400 (NiCu30Fe, UNS N04400) is a solid-solution nickel-copper alloy with no deliberate aluminium or titanium and cannot be age hardened. NiCu30Al adds 2.2–3.5% aluminium and 0.3–1.0% titanium, which allows precipitation hardening to a minimum tensile strength of 931 N/mm² against approximately 480–550 N/mm² for annealed Monel 400.
Corrosion resistance is broadly equivalent. NiCu30Al is therefore selected where the same corrosion performance is required at much higher strength, for example pump and propeller shafts, valve stems, fasteners and drill collar components.
Is NiCu30Al magnetic?
No. The Curie temperature of NiCu30Al lies well below room temperature, so the alloy is essentially non-magnetic in normal service. This is the reason it is specified for non-magnetic drill collars and for instrumentation housings in measurement-while-drilling assemblies, where a ferromagnetic component would corrupt directional survey readings.
Can NiCu30Al forgings be used in sour service?
Yes, within limits. NACE MR0175 / ISO 15156 accepts age-hardened UNS N05500 for sour service but caps the supply hardness at 35 HRC. Jiangyin Jiangnan Metal controls the ageing cycle to keep hardness within that limit and reports the measured hardness on the EN 10204 3.1 or 3.2 certificate.
State sour service on the enquiry so that the ageing schedule, hardness survey positions and test frequency are agreed before production starts.
What heat treatment is applied to NiCu30Al forgings?
Forgings are solution treated in the region of 1010–1065 °C, quenched, then age hardened with a controlled multi-step cycle between 480 °C and 595 °C followed by slow furnace cooling. The ageing step develops the gamma-prime precipitate and raises the proof stress from approximately 275 N/mm² in the solution-treated condition to the 655 N/mm² minimum required in the aged condition.
What is the maximum service temperature for NiCu30Al?
Approximately 480 °C (900 °F) in the age-hardened condition. Above this temperature the gamma-prime precipitate coarsens and the alloy over-ages, losing the strength produced by the ageing treatment. For continuous service above 500 °C, a solid-solution or higher-temperature nickel alloy such as Inconel 625 or Incoloy 800H is the correct choice.
What sizes of NiCu30Al forgings can be produced?
Jiangyin Jiangnan Metal produces NiCu30Al seamless rolled rings up to approximately 2,500 mm outside diameter, forged shafts up to approximately 6,000 mm long, forged discs up to approximately 2,500 mm diameter, and single pieces from approximately 5 kg to 3,000 kg. Nickel alloy ingot supply governs the practical size ceiling, so confirm large or heavy sections at enquiry stage before designing around them.
What testing and certification is supplied with NiCu30Al forgings?
Standard scope covers chemical analysis, tensile and hardness testing after ageing, and ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388 as specified. Liquid penetrant examination, positive material identification, impact testing and grain size assessment are available on request. Material is certified to EN 10204 3.1, or to EN 10204 3.2 with third-party witness by an agency such as Lloyd's Register, BV, DNV, TUV or SGS.
How do I request a quotation for NiCu30Al forgings?
Send a drawing or the finished dimensions, the quantity, the governing specification, the required condition and the test and certification scope to sales@steelforgepieces.com, or call +86 189 2135 9659. Jiangyin Jiangnan Metal Co., Ltd. is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, and quotes NiCu30Al enquiries within one working day.