UNS N04400 (Monel 400) Forgings: Rolled Rings, Flanges, Bars, Discs and Shafts
Overview
UNS N04400 is a nickel-copper alloy containing a minimum of 63 % nickel and 28 to 34 % copper. It is widely known by the trade name Monel 400 and by the European designation W.Nr. 2.4360 (NiCu30Fe). The alloy is a solid solution and cannot be hardened by heat treatment, so forgings are supplied annealed, with a minimum tensile strength of 480 MPa (70 ksi), a minimum 0.2 % proof stress of 170 MPa (25 ksi) and 35 % minimum elongation.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges UNS N04400 to ASTM B564 as seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings and tube sheets, in diameters from 80 mm to 6,000 mm, single-piece weights from 10 kg to 15,000 kg and lengths up to 12,000 mm, certified to EN 10204 3.1 or 3.2.
- UNS number
- N04400
- Trade name
- Monel 400
- Werkstoff Nr.
- 2.4360
- Alloy type
- Ni-Cu, solid solution
- Forging spec
- ASTM B564
- Density
- 8.80 g/cm³
- Tensile min.
- 480 MPa / 70 ksi
- Max hardness
- 35 HRC (MR0175)
What is UNS N04400?
UNS N04400 is a nickel-copper alloy containing at least 63 % nickel and 28 to 34 % copper, with iron limited to 2.5 % and manganese to 2.0 %. Nickel and copper are mutually soluble in all proportions, so the alloy forms a single face-centred-cubic solid solution with no strengthening precipitates. It keeps high toughness from cryogenic temperatures up to about 480 °C, welds readily, and does not respond to hardening heat treatment.
The alloy is usually encountered under the trade name Monel 400, a registered trademark of Special Metals Corporation. Trade names cannot be applied to material from other producers, so purchase specifications and mill certificates normally use the UNS designation N04400 or the European Werkstoff number 2.4360. Jiangyin Jiangnan Metal supplies and certifies the alloy as UNS N04400 to ASTM B564.
N04400 contains no chromium, so it does not rely on a passive oxide film. It performs best in reducing environments such as hydrofluoric acid, dilute sulphuric acid, hydrochloric acid at moderate concentration, alkalis and salt solutions, where chromium-passivated alloys lose their film. It is not the right choice for strongly oxidising media such as nitric acid, wet chlorine, or oxidising ferric and cupric salts.
Standards and equivalent designations for UNS N04400
| System / country | Designation | Notes |
|---|---|---|
| UNS (USA) | N04400 | Primary purchasing designation |
| Trade name | Monel 400, Alloy 400, Nickel 400 | Monel is a Special Metals trademark |
| Germany (DIN / EN) | 2.4360, NiCu30Fe | DIN 17750 to 17754 |
| UK (BS) | NA13 | BS 3076 / BS 3072 |
| France (AFNOR) | NU-30 | |
| Japan (JIS) | NW4400 / NCuP | JIS H 4551 |
| China (GB/T) | NCu30 | GB/T 15007 equivalent |
| Forgings | ASTM B564 / ASME SB-564 | Specification used for all Jiangnan N04400 forgings |
| Rod and bar | ASTM B164 / ASME SB-164 | Also AMS 4675 |
| Plate and sheet | ASTM B127 | |
| Seamless pipe and tube | ASTM B165 / B163 | |
| Fittings | ASTM B366 | WPNC grade |
| Sour service | NACE MR0175 / ISO 15156-3 | Hardness 35 HRC maximum |
| US federal | QQ-N-281 Class A / B | Legacy naval specification |
Chemical composition of UNS N04400
The composition limits below apply to UNS N04400 forgings supplied to ASTM B564. Every heat is analysed by optical emission spectrometry and reported on the EN 10204 3.1 certificate against the heat number stamped on the forging.
| Limit | Ni | Cu | Fe | Mn | C | Si | S |
|---|---|---|---|---|---|---|---|
| Minimum | 63.0 | 28.0 | |||||
| Maximum | balance | 34.0 | 2.5 | 2.0 | 0.30 | 0.50 | 0.024 |
Nickel plus cobalt counts together toward the 63 % minimum. The 0.024 % sulphur ceiling matters in production: sulphur causes hot shortness during forging, so both the melt chemistry and the furnace atmosphere are controlled for sulphur, and billets are degreased before heating.
Mechanical properties of UNS N04400 forgings
| Property | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength | 480 MPa min. | 70 ksi min. |
| 0.2 % proof stress (yield) | 170 MPa min. | 25 ksi min. |
| Elongation in 4D | 35 % min. | 35 % min. |
| Hardness, annealed | 110 to 150 HB typical | 60 to 80 HRB typical |
| Hardness limit, sour service | 35 HRC maximum per NACE MR0175 / ISO 15156-3 | |
| Modulus of elasticity | 179 GPa | 26 × 10⁶ psi |
| Impact toughness | Ductile to −200 °C, with no ductile-to-brittle transition | |
Strength above these minima comes from cold work, not from heat treatment. Where a forging must combine alloy 400 corrosion resistance with yield strength above about 400 MPa, the correct material is the age-hardenable grade UNS N05500 (Monel K-500).
Physical properties of UNS N04400
| Property | Value (metric) | Value (imperial) |
|---|---|---|
| Density | 8.80 g/cm³ | 0.318 lb/in³ |
| Melting range | 1,300 to 1,350 °C | 2,370 to 2,460 °F |
| Thermal conductivity | 21.8 W/m·K | 151 Btu·in/h·ft²·°F |
| Specific heat | 427 J/kg·K | 0.102 Btu/lb·°F |
| Mean thermal expansion, 20 to 100 °C | 13.9 µm/m·K | 7.7 µin/in·°F |
| Electrical resistivity | 0.547 µΩ·m | 329 Ω·circ mil/ft |
| Curie temperature | About 20 to 50 °C depending on composition, so the alloy is weakly magnetic at ambient | |
| Maximum continuous service temperature | About 480 °C | About 900 °F |
Corrosion resistance of UNS N04400
UNS N04400 is specified where reducing acids and salt-bearing water attack stainless steel. The behaviour below is established in the technical literature and matches service experience with forgings supplied by Jiangyin Jiangnan Metal.
- Hydrofluoric acid. N04400 resists HF at all concentrations and up to high temperatures, and remains the standard material for HF alkylation units, acid regeneration and HF transfer equipment.
- Flowing seawater. Good resistance to erosion-corrosion and cavitation at high velocity, which is why the alloy is used for pump shafts, propeller shafts, valve trim and seawater piping components.
- Stagnant seawater. Pitting and crevice corrosion can occur under deposits, under biofouling or in crevices at low flow. Where sustained low-flow seawater is expected, Incoloy 825 or a super duplex stainless steel is the better choice.
- Alkalis. High resistance to caustic soda and caustic potash at all concentrations and temperatures, including resistance to caustic stress-corrosion cracking.
- Sulphuric and hydrochloric acid. Good resistance in dilute, air-free conditions. Resistance falls sharply when oxidising contaminants such as ferric or cupric ions are present.
- Chloride stress-corrosion cracking. N04400 is effectively immune, unlike austenitic stainless steels.
- Not suitable for nitric acid, wet chlorine, moist ammonia in the presence of oxygen, and strongly oxidising salts.
Forging and heat treatment of UNS N04400
Melting route
The alloy is melted by EAF plus VOD followed by electroslag remelting (ESR). VIM plus ESR plus VAR is used where the customer specification calls for the lowest gas and inclusion content. ESR refines sulphur and oxide inclusions, which governs how safely the ingot can be hot worked.
Forging practice
- Charge temperature 1,150 to 1,200 °C. The 1,200 °C ceiling is not exceeded, since incipient melting begins at about 1,300 °C.
- Heavy reduction between 1,200 °C and 1,040 °C, with finishing passes down to about 870 to 930 °C to refine grain size.
- Minimum forging ratio 3:1 from the ESR ingot, and 4:1 or higher for ring blanks and pressure-boundary parts.
- Furnace atmosphere kept low in sulphur and the billet degreased before heating, because sulphur pick-up causes intergranular hot cracking in nickel-copper alloys.
- Equipment: 1 t, 3 t, 6 t and 9 t forging hammers, a 4,500 t hydraulic press, and 3-metre and 6-metre seamless ring-rolling mills.
Heat treatment
| Treatment | Temperature | Purpose |
|---|---|---|
| Annealing (standard supply condition) | 870 to 980 °C, then rapid cool | Recrystallises the structure and restores full ductility and corrosion resistance |
| Stress relief | 540 to 590 °C | Relieves machining and welding stresses without softening cold-worked material |
| Solution and ageing | Not applicable. N04400 contains no age-hardening phases. Specify UNS N05500 where age hardening is required. | |
UNS N04400 forged product forms and size range
Jiangyin Jiangnan Metal produces the following UNS N04400 forged forms to customer drawing or to free-form dimensions. All are open-die forged or ring-rolled. No castings are supplied.
| Product form | Size range | Typical use |
|---|---|---|
| Seamless rolled rings | OD 80 to 6,000 mm, weight 10 to 15,000 kg | Pump casings, valve bodies, flange blanks, bearing rings |
| Forged flanges | DN 15 to DN 2000, WN / SO / BL to ASME B16.5 and B16.47 | HF service piping, heat exchangers, columns |
| Forged round bars | Dia. 20 to 1,200 mm, length to 12,000 mm | Shafts, stems, fastener stock, machining blanks |
| Forged discs and disks | Dia. 100 to 3,000 mm | Blind flanges, closures, tube-sheet blanks |
| Forged tube sheets | Dia. to 3,000 mm, thickness to 500 mm | Shell-and-tube heat exchangers |
| Forged shafts and spindles | Dia. 50 to 1,000 mm, length to 12,000 mm | Chemical pumps, plunger pumps, propeller shafts |
| Forged sleeves and bushings | OD 100 to 2,000 mm | Subsea equipment, compressors, wear parts |
| Forged hollow bars and thick-wall pipe | OD 150 to 1,500 mm | Cylinders, liners, nozzle bodies |
| Forged valve components | Per drawing | Bodies, bonnets, stems, seat rings, plugs, blocks |
| Forged blocks and nozzles | Per drawing, to 15,000 kg | Pressure-vessel nozzles, manifolds, die blocks |
Machining scope is selectable: as-forged with allowance, rough machined, or finish machined to drawing tolerance. Rough machining before final heat treatment is recommended on rings above 2,000 mm OD to control distortion.
Applications for UNS N04400 forgings by industry
Oil, gas and refining
HF alkylation unit valves, flanges, tube sheets and piping components; wellhead and Christmas-tree parts; subsea and deepwater production components; sour-service parts certified to NACE MR0175 / ISO 15156-3 with hardness at or below 35 HRC.
Chemical processing
Forged shafts and rolled rings for chemical and plunger pumps; columns, towers, reactors, crystallisers, preheaters and evaporator components; caustic evaporation equipment where resistance to caustic stress-corrosion cracking is required.
Marine and desalination
Propeller and pump shafts, valve trim, seawater strainer bodies, fasteners and shafting exposed to high-velocity seawater; brine heater and desalination plant components.
Heat exchangers and pressure equipment
Forged tube sheets, shell flanges, channel covers, nozzles and air-receiver components for shell-and-tube heat exchangers, pressure vessels and boilers.
Power, rotating and heavy equipment
Forged gears, rings, spindles and bars for turbines, gas compressors and gearboxes; forged rolls, wheels, manifolds and crankshafts for cement mills, sugar mills, mixers, shipbuilding, pulp and paper, and pharmaceutical and biochemical plant.
UNS N04400 compared with K-500, Incoloy 825 and Inconel 625
| Alloy | Key chemistry | Yield strength (min.) | Strengthening | Suited to |
|---|---|---|---|---|
| UNS N04400 (Monel 400) | Ni 63 min, Cu 28 to 34 | 170 MPa | Solid solution only | HF acid, caustic, flowing seawater, reducing acids |
| UNS N05500 (Monel K-500) | Ni-Cu plus Al 2.3 to 3.15, Ti 0.35 to 0.85 | About 690 MPa aged | Age hardening | Same corrosion service with high strength: shafts, bolting, pump impellers |
| UNS N08825 (Incoloy 825) | Ni 38 to 46, Cr 19.5 to 23.5, Mo 2.5 to 3.5 | 240 MPa | Solid solution | Mixed oxidising and reducing service, sulphuric and phosphoric acid, stagnant seawater |
| UNS N06625 (Inconel 625) | Ni 58 min, Cr 20 to 23, Mo 8 to 10, Nb | 414 MPa | Solid solution | High-temperature strength, pitting and crevice resistance in chlorides, seawater |
Selection guide: for reducing environments, specify N04400. For oxidising environments or stagnant chlorides, specify a chromium-bearing alloy such as Incoloy 825 or Inconel 625. Where alloy 400 corrosion resistance is needed together with high strength, specify UNS N05500.
Testing, non-destructive examination and certification
- Chemical analysis per heat by optical emission spectrometry, with positive material identification on the finished forging on request.
- Mechanical testing: tensile, elongation, reduction of area, Brinell and Rockwell hardness. Charpy impact testing including sub-zero temperatures on request.
- Ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388, with the acceptance class stated on the order.
- Liquid penetrant examination to ASTM E165 for surface flaws. Magnetic particle inspection is not used on N04400 because its Curie temperature sits near ambient.
- Dimensional inspection report against the customer drawing.
- Certification: EN 10204 3.1 as standard, EN 10204 3.2 witnessed by TUV, SGS, BV, Lloyd's Register or DNV on request. NACE MR0175 / ISO 15156-3 compliance statements issued for sour service.
How to order UNS N04400 forgings
- Send the enquiry. Email the drawing, dimensions or rough sizes, quantity, standard such as ASTM B564, and certificate level to sales@steelforgepieces.com. A formal drawing is not required for a budget price; OD × ID × height, or diameter × length, is enough.
- Receive the quotation within 24 working hours, covering forging weight, unit price, machining allowance, testing scope and lead time.
- Approve the inspection and test plan covering melting route, forging ratio, heat treatment, mechanical testing and NDT.
- Manufacture and test: melting, forging, annealing at 870 to 980 °C, machining and full testing.
- Certification and shipment under EN 10204 3.1 or 3.2, packed in fumigated cases, on EXW, FOB Shanghai or CIF terms. Lead time is 25 to 45 days.
Request a quotation for UNS N04400 forgings
Send your drawing or size list and we will quote within one working day.
- Company
- Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Phone / WhatsApp
- 0086-189-2135-9659
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
Frequently asked questions about UNS N04400
Is UNS N04400 the same as Monel 400?
Yes. UNS N04400 is the UNS number for the alloy sold under the trade name Monel 400, a registered trademark of Special Metals Corporation. The same alloy is 2.4360 or NiCu30Fe in Germany, NA13 in BS 3076, NW4400 in JIS and NCu30 in Chinese GB standards. Jiangyin Jiangnan Metal supplies and certifies it under the UNS designation.
Can UNS N04400 be hardened by heat treatment?
No. UNS N04400 is a solid-solution alloy with no age-hardening precipitates, so solution treatment plus ageing gives no strength increase. Higher strength comes only from cold work, or from switching to the age-hardenable grade UNS N05500 (Monel K-500), which contains aluminium and titanium. N04400 forgings are annealed at 870 to 980 °C and cooled rapidly.
What is the difference between UNS N04400 and UNS N05500?
Both are nickel-copper alloys with comparable corrosion resistance, but UNS N05500 adds about 2.3 to 3.15 % aluminium and 0.35 to 0.85 % titanium, which allows age hardening to roughly 690 MPa yield strength and 27 to 35 HRC. UNS N04400 has 170 MPa minimum yield strength and cannot be aged. N04400 suits corrosion service, N05500 suits high-strength shafts, bolting and pump parts.
Which standard covers UNS N04400 forgings?
ASTM B564, and its ASME equivalent SB-564, is the specification for nickel alloy forgings including UNS N04400. Related specifications are ASTM B127 for plate and sheet, B164 for rod, bar and wire, B165 for seamless pipe and tube, and B366 for fittings. Sour-service forgings are also supplied to NACE MR0175 / ISO 15156-3 with hardness limited to 35 HRC.
Why is UNS N04400 used for hydrofluoric acid service?
N04400 resists hydrofluoric acid across the full concentration range and at elevated temperature better than stainless steels or most nickel-chromium alloys, because the nickel-copper matrix does not depend on a passive chromium oxide film in reducing acids. It is the standard material for HF alkylation units, HF storage and transfer equipment, and the associated valves, flanges and tube sheets.
Does UNS N04400 resist seawater?
In flowing seawater, yes. N04400 resists the erosion-corrosion and cavitation that attack copper alloys, which is why it is used for pump shafts, propeller shafts, valve trim and seawater piping. In stagnant or low-velocity seawater, deposits and biofouling can cause pitting and crevice attack, and Incoloy 825 or super duplex is normally preferred.
Is UNS N04400 magnetic?
It is weakly ferromagnetic, with a Curie temperature of roughly 20 to 50 °C depending on exact composition, so a sample may or may not attract a magnet at room temperature. Because magnetic behaviour is unreliable near ambient, surface flaw detection on N04400 forgings uses liquid penetrant examination rather than magnetic particle inspection.
Can UNS N04400 be welded?
Yes, by GTAW, GMAW and SMAW using matching ERNiCu-7 filler wire or ENiCu-7 electrodes. No preheat or post-weld heat treatment is normally required. Surfaces must be free of sulphur-bearing contaminants such as grease, marking paint and cutting fluid before heating, because sulphur causes intergranular embrittlement and hot cracking in nickel-copper alloys.
What size UNS N04400 forgings can you produce?
Jiangyin Jiangnan Metal Co., Ltd. produces UNS N04400 open-die forgings with diameters from 80 mm to 6,000 mm, single-piece weights from 10 kg to 15,000 kg and lengths up to 12,000 mm. The plant operates 1, 3, 6 and 9 tonne forging hammers, a 4,500 tonne hydraulic press and 3-metre and 6-metre seamless ring-rolling mills at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China.
What certificates are supplied?
Every forging is released with an EN 10204 3.1 mill certificate showing heat number, chemical analysis, mechanical results, heat treatment record and NDT report. EN 10204 3.2 certificates witnessed by TUV, SGS, BV, Lloyd's Register or DNV are available on request, together with PMI reports and third-party ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388.
What is the lead time for custom UNS N04400 forgings?
25 to 45 days from order confirmation, depending on the ESR ingot size required, the machining scope and the certificate level. Quotations are issued within 24 working hours of receiving a drawing or size list at sales@steelforgepieces.com.
What is the density and melting range of UNS N04400?
Density is 8.80 g/cm³ (0.318 lb/in³) and the melting range is 1,300 to 1,350 °C (2,370 to 2,460 °F). Modulus of elasticity is 179 GPa, mean thermal expansion between 20 and 100 °C is 13.9 µm/m·K, and maximum continuous service temperature is about 480 °C.
About the supplier
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The company employs 460 people, including 9 senior engineers and 32 intermediate engineers, and manufactures open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including UNS N04400 (Monel 400), with diameters from 80 mm to 6,000 mm and single-piece weights from 10 kg to 15,000 kg.
Production is integrated in-house: raw material melting by EAF plus VOD plus ESR or VIM plus ESR plus VAR, open-die forging on 1 to 9 tonne hammers and a 4,500 tonne hydraulic press, ring rolling on 3-metre and 6-metre mills, heat treatment, machining, and mechanical and non-destructive testing. Forgings are certified to EN 10204 3.1 or 3.2 and shipped worldwide. Enquiries: sales@steelforgepieces.com or 0086-189-2135-9659.
Standards referenced on this page
- ASTM B564 / ASME SB-564, Standard Specification for Nickel Alloy Forgings
- ASTM B127 / B164 / B165 / B366, alloy 400 plate, rod, tube and fittings
- NACE MR0175 / ISO 15156-3, materials for use in H₂S-containing environments
- EN 10204, types of inspection documents for metallic products
- EN 10228-3, SEP 1921 and ASTM A388, ultrasonic examination of forgings
- ASTM E165, liquid penetrant examination
- DIN 17750 to 17754 (2.4360 / NiCu30Fe), BS 3076 (NA13), JIS H 4551 (NW4400), GB/T (NCu30)