Nickel-copper alloy, UNS N04405, W.Nr. 2.4361
Monel R-405 Forgings (UNS N04405): Forged Bar, Rolled Rings, Flanges and Valve Parts
In short
Monel R-405 (UNS N04405, W.Nr. 2.4361) is the free-machining grade of Monel 400. It is a nickel-copper alloy with a minimum of 63% nickel and 28 to 34% copper, plus a controlled sulfur addition of 0.025 to 0.060%. The sulfur forms sulfide inclusions that break chips during machining. Corrosion resistance in seawater, steam, caustics and hydrofluoric acid matches alloy 400, while machinability is roughly double.
Jiangyin Jiangnan Metal Co., Ltd. manufactures Monel R-405 open-die forgings, forged round bar, seamless rolled rings, flanges, discs, sleeves, shafts, tube sheets and valve components to ASTM B164 / ASME SB-164. Parts are supplied with EN 10204 3.1 or 3.2 material certificates from the factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China.
- UNS
- N04405
- Werkstoff
- 2.4361
- Nickel
- 63% min
- Copper
- 28–34%
- Sulfur
- 0.025–0.060%
- Density
- 8.80 g/cm³
- Specification
- ASTM B164
- Certificate
- EN 10204 3.1
Chemical composition of Monel R-405
ASTM B164 and ASME SB-164 fix the composition of UNS N04405. Sulfur is the one element that separates R-405 from Monel 400: alloy 400 is capped at 0.024%, while R-405 requires at least 0.025%.
| Element | Minimum | Maximum | Function |
|---|---|---|---|
| Nickel (Ni + Co) | 63.0 | – | Solid-solution matrix, chloride SCC resistance |
| Copper (Cu) | 28.0 | 34.0 | Seawater and reducing-acid resistance |
| Sulfur (S) | 0.025 | 0.060 | Forms sulfide chip breakers, the free-machining addition |
| Iron (Fe) | – | 2.50 | Residual |
| Manganese (Mn) | – | 2.00 | Deoxidiser, sulfur control |
| Carbon (C) | – | 0.30 | Residual |
| Silicon (Si) | – | 0.50 | Deoxidiser |
Composition per ASTM B164 / ASME SB-164, UNS N04405. Nickel is reported inclusive of cobalt. Every heat supplied by Jiangyin Jiangnan Metal Co., Ltd. carries ladle and product analysis on the mill test certificate.
Mechanical properties of Monel R-405
R-405 is a solid-solution alloy. Strength comes from retained cold work rather than from heat treatment, so the delivery condition has to be stated on the order.
| Property | Annealed | Cold-drawn / stress-relieved |
|---|---|---|
| Tensile strength | 483–586 MPa (70–85 ksi) | 586–758 MPa (85–110 ksi) |
| Yield strength, 0.2% offset | 172–276 MPa (25–40 ksi) | 379–586 MPa (55–85 ksi) |
| Elongation in 4D | 35–50% | 15–30% |
| Hardness | 110–149 HB | 150–210 HB |
| Hardening mechanism | Cold work only. Monel R-405 is not age-hardenable. | |
Typical values for guidance. Certified values are those of the applicable specification, section size and temper stated on your purchase order.
Physical properties of Monel R-405
Sulfur is present in small, controlled amounts, so the physical properties of R-405 track those of Monel 400 closely enough that alloy 400 data is normally used for design work.
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.80 g/cm³ | 0.318 lb/in³ |
| Melting range | 1300–1350 °C | 2370–2460 °F |
| Modulus of elasticity (tension) | 179 GPa | 26 × 106 psi |
| Coefficient of thermal expansion (20–100 °C) | 13.9 µm/m·°C | 7.7 × 10-6 in/in·°F |
| Thermal conductivity (20 °C) | 21.8 W/m·K | 151 Btu·in/h·ft²·°F |
| Specific heat (20 °C) | 427 J/kg·K | 0.102 Btu/lb·°F |
| Electrical resistivity (20 °C) | 547 nΩ·m | 329 Ω·circ mil/ft |
| Magnetic response | Slightly ferromagnetic at room temperature. Curie temperature varies with composition, typically 20 to 50 °C. | |
| Machinability rating (B1112 = 100%) | About 44%, roughly double that of Monel 400 at about 20% | |
| Useful service range | Cryogenic to about 480 °C (900 °F) in continuous service | |
Specifications, equivalents and trade names
| System | Designation |
|---|---|
| UNS | N04405 |
| Werkstoff / EN | 2.4361 (Monel 400 = 2.4360) |
| ASTM / ASME | ASTM B164, ASME SB-164, covering rod, bar and wire |
| SAE AMS | AMS 4674, AMS 7234 |
| Federal / Military | QQ-N-281, MIL-N-894 |
| Sour service | NACE MR0175 / ISO 15156 |
| Common names | Monel® R-405, Monel R405, Alloy R-405, Nickel-Copper Alloy 405, NiCu30Fe free-machining variant |
Monel® is a registered trademark of Special Metals Corporation. Jiangyin Jiangnan Metal Co., Ltd. is an independent forging manufacturer with no affiliation to Special Metals Corporation. The designation is used here to identify the alloy grade.
Monel R-405 forgings we manufacture
Jiangyin Jiangnan Metal Co., Ltd. produces Monel R-405 forgings to customer drawing, supplied as forged, rough machined or finish machined. Standard forms include:
- Forged round bar and hexagon bar
- Seamless rolled rings and ring blanks
- Forged flanges: weld neck, blind, slip-on, ring joint
- Forged discs, blanks and tube sheets
- Forged sleeves, bushings and hollow bar
- Forged shafts, stems and spindles
- Forged blocks, rectangles and plates
- Valve bodies, bonnets, seat rings, gates and plugs
- Pump shafts, impeller hubs and wear rings
- Nozzles, couplings and custom near-net shapes
| Form | Range |
|---|---|
| Forged round bar | Ø 40–800 mm, length up to 6,000 mm |
| Seamless rolled rings | OD 200–3,000 mm, wall 20–400 mm, height 20–800 mm |
| Forged discs and blanks | Ø 100–2,500 mm, thickness 20–600 mm |
| Forged sleeves and hollow bar | OD 100–1,500 mm, ID from 60 mm |
| Forged shafts and stems | Ø 30–600 mm, length up to 6,000 mm |
| Single-piece weight | 5 kg to 20,000 kg |
| Order quantity | Single prototype piece up to series production |
How Monel R-405 forgings are manufactured
1. Melting
Monel R-405 is melted by EAF plus AOD or VOD. ESR remelting is available where tighter sulfide distribution and better soundness are needed. Sulfur is trimmed into the 0.025 to 0.060% window rather than removed, and manganese is balanced against it so the sulfides stay fine and evenly dispersed instead of forming grain-boundary films.
2. Forging
Ingots or billets are homogenised, then open-die forged or ring rolled. Start temperature is 1150 to 1180 °C. Passes are kept light, the piece is reheated often, and finishing below about 870 °C is avoided. Total reduction is planned to close porosity and refine grain without the heavy upsetting that a low-sulfur grade would take.
3. Heat treatment
R-405 is annealed at 870 to 925 °C and cooled quickly. Cold-drawn product is stress relieved at 275 to 300 °C. There is no solution and age cycle for this grade, as explained under forgeability below.
4. Testing and inspection
- Chemical analysis by OES or ICP, ladle and product, per ASTM E1473
- Tensile testing per ASTM E8/E8M, hardness per ASTM E10 or E18
- Ultrasonic testing per ASTM E2375 for wrought products, or ASTM A388, SEP 1921 and EN 10228-3 where nominated by the customer
- Liquid penetrant testing per ASTM E165 or ASME Section V
- Grain size per ASTM E112, with macro-etch and microstructure on request
- Positive material identification by XRF or portable OES
- Dimensional inspection report against the approved forging drawing
5. Certification
Every heat is supplied with an EN 10204 3.1 mill test certificate showing heat number, chemical analysis, mechanical results, heat-treatment record and NDT results. EN 10204 3.2 certificates witnessed by TUV, BV, DNV, Lloyd's Register or SGS are issued on request. Parts are hard-stamped or vibro-marked with grade and heat number for traceability.
Can Monel R-405 be forged? When to use Monel 400 instead
Sulfur makes R-405 free-machining, and it also lowers hot ductility. ASTM B164 standardises the grade as rod, bar and wire, and that is how it is normally supplied. Two consequences follow.
- If the part will be welded, meaning pressure-retaining shells, nozzles, cladding or weld-neck assemblies, specify Monel 400 (UNS N04400). R-405 can be welded but is hot-crack sensitive, and most fabrication codes prefer alloy 400.
- If the part needs heavy upsetting or a high forging reduction, such as large rolled rings, deep shapes or thick flanges, specify Monel 400. Corrosion resistance is the same and there is no forging restriction.
Specify Monel R-405 when machining cost is the driver: high-volume screw-machine parts, valve stems, seat rings, meter internals and fasteners cut from forged or drawn bar. Both grades are produced here, and we will tell you which one the drawing needs.
Monel R-405 compared with Monel 400 and Monel K-500
| Criterion | Monel R-405 | Monel 400 | Monel K-500 |
|---|---|---|---|
| UNS | N04405 | N04400 | N05500 |
| Sulfur | 0.025–0.060% | 0.024% max | 0.010% max |
| Key addition | Sulfur, for chip breaking | None | Al and Ti, for age hardening |
| Strengthening | Cold work only | Cold work only | Solution plus age hardening |
| Tensile, annealed | 483–586 MPa | 483–586 MPa | 620–758 MPa, aged 965–1170 MPa |
| Machinability | Best, about 44% | Moderate, about 20% | Difficult |
| Weldability | Restricted, hot-crack sensitive | Good | Good, requires re-age |
| Forgeability | Limited, narrow hot window | Good | Good |
| Typical use | Screw-machine parts, valve stems, fasteners | Vessels, pumps, piping, heat exchangers | Pump shafts, doctor blades, subsea bolting |
Related grades from the same factory: Monel 400 forgings and Monel K-500 forgings.
Applications for Monel R-405 forgings
Marine and offshore
- Seawater valve stems, seat rings and internals
- Pump and propeller shafts, wear rings
- Marine fasteners and deck hardware
- Subsea and wellhead components, Christmas tree parts
Chemical and petrochemical
- Hydrofluoric acid alkylation plant components
- De-aerated hydrochloric and sulfuric acid service
- Chemical process pump and plunger pump parts
- Pickling bath coils and transfer piping fittings
Power, desalination and heat transfer
- Feedwater and steam-generator components
- Heat exchanger tube sheets and baffles
- Brine heaters and evaporator bodies
- Seawater scrubbers in tanker inert-gas systems
Precision machined components
- Automatic screw-machine stock, the primary use of the grade
- Meter, instrument and gauge parts
- Electrical connectors and contacts
- Uranium refining and isotope-separation equipment
Corrosion behaviour
Monel R-405 resists flowing seawater, brackish water and steam at elevated temperature, along with neutral and alkaline salts and caustic solutions. It is one of the few commercial alloys with useful resistance to hydrofluoric acid, and it performs well in de-aerated hydrochloric and sulfuric acids. Resistance to chloride-induced stress-corrosion cracking is high, which is where it beats austenitic stainless steels such as 316L.
The alloy is not suitable for oxidising acids such as nitric acid, for oxidising salts such as ferric or cupric chloride, for aerated ammonia solutions, or for environments containing mercury or molten sulfur. Aeration speeds up attack in reducing acids, so oxygen ingress has to be controlled in acid service.
How to order
Send a drawing or dimensions to sales@steelforgepieces.com. To return a firm quotation, Jiangyin Jiangnan Metal Co., Ltd. needs:
- Drawing or finished dimensions, as 2D PDF, DWG, 3D model or a dimensioned sketch
- Grade and specification, for example Monel R-405 / UNS N04405 to ASTM B164 or to your own spec
- Delivery condition and machining allowance: as forged, annealed, rough machined or finish machined
- Quantity and required delivery date
- NDT and certification requirements, including UT acceptance level, PT, and EN 10204 3.1 or 3.2
- Destination port and preferred Incoterm
Quotations are normally returned within 24 hours. Samples, first-article inspection and third-party witnessed testing can all be arranged.
Frequently asked questions about Monel R-405
What is Monel R-405?
Monel R-405 (UNS N04405, W.Nr. 2.4361) is the free-machining grade of Monel 400. It is a nickel-copper alloy with a minimum of 63% nickel and 28 to 34% copper, plus a controlled sulfur addition of 0.025 to 0.060%. The sulfur forms nickel-copper sulfide inclusions that break chips during machining, which roughly doubles machinability against Monel 400 while corrosion resistance and physical properties stay the same.
What is the difference between Monel 400 and Monel R-405?
Sulfur is the only deliberate difference. Monel 400 (UNS N04400) is capped at 0.024% sulfur, while Monel R-405 (UNS N04405) requires 0.025 to 0.060%. That addition makes R-405 far easier to machine on automatic screw machines, but it lowers hot ductility, gives a rougher machined surface and raises hot-cracking sensitivity during welding. Use R-405 for high-volume machined parts and Monel 400 for welded fabrications, heavily hot-worked forgings and pressure-retaining components.
Can Monel R-405 be forged?
It can, with care. The sulfur that gives R-405 its machinability also causes hot shortness, so the safe hot-working window is narrower than for Monel 400 and the grade is normally supplied as rod and bar rather than as heavy forgings.
Jiangyin Jiangnan Metal Co., Ltd. forges R-405 from a controlled 1150 to 1180 °C start temperature, with light reductions, reheating between passes and no finishing below about 870 °C. Where a part is welded, pressure-retaining, or needs heavy upsetting, we recommend Monel 400 (UNS N04400), which has almost the same corrosion resistance and forges without restriction.
Can Monel R-405 be hardened by heat treatment?
No. Monel R-405 is a solid-solution alloy and cannot be age-hardened or quench-hardened. Strength is raised only by cold work. Heat treatment is limited to annealing at about 870 to 925 °C followed by rapid cooling, and stress relief at 275 to 300 °C after cold drawing. Age hardening applies to Monel K-500 (UNS N05500), which contains aluminium and titanium. It does not apply to R-405 or Monel 400.
Which standards and specifications cover Monel R-405?
ASTM B164 and ASME SB-164 for rod, bar and wire, SAE AMS 4674 and AMS 7234, Federal specification QQ-N-281, Military specification MIL-N-894, and NACE MR0175 / ISO 15156 for sour service. The UNS number is N04405 and the Werkstoff number is 2.4361.
Is Monel R-405 weldable?
Monel R-405 can be joined by GTAW, SMAW, brazing and soldering, but the raised sulfur level makes the weld and heat-affected zone sensitive to hot cracking. Many purchasers restrict R-405 to machined components and call for Monel 400 on anything that will be welded. If R-405 must be welded, use a matching or ERNiCu-7 filler, low heat input and minimal restraint, then clean the surface thoroughly to protect corrosion resistance.
How machinable is Monel R-405?
Monel R-405 rates at roughly 44% against free-cutting steel AISI B1112 at 100%, against roughly 20% for Monel 400. The sulfide inclusions break chips cleanly, which is why R-405 is the usual choice for automatic screw-machine stock, valve stems, meter parts and fasteners. The cost is a rougher machined surface finish than Monel 400 gives.
Is Monel R-405 resistant to seawater and hydrofluoric acid?
Yes. Corrosion resistance matches Monel 400. Monel R-405 resists flowing seawater, brackish water, steam, neutral and alkaline salts and caustic solutions, and it is one of the few alloys that performs well in hydrofluoric acid and in de-aerated hydrochloric and sulfuric acids. It also resists chloride stress-corrosion cracking. It is not suitable for oxidising acids such as nitric acid, or for aerated ammonia and mercury-bearing environments.
Who manufactures Monel R-405 forgings in China?
Jiangyin Jiangnan Metal Co., Ltd. manufactures Monel R-405 (UNS N04405) forgings in China. The factory is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, and produces open-die forgings, seamless rolled rings, forged flanges, discs, shafts, sleeves and valve components in Monel R-405, Monel 400, Monel K-500 and other nickel alloys. Enquiries go to sales@steelforgepieces.com or +86-189-2135-9659.
What certification is supplied with Monel R-405 forgings?
An EN 10204 3.1 mill test certificate as standard, covering heat number, full chemical analysis, mechanical test results, heat-treatment record and non-destructive test results. EN 10204 3.2 certification witnessed by a third party such as TUV, BV, DNV, Lloyd's Register or SGS is available on request.
What information is needed to quote a Monel R-405 forging?
The drawing or finished dimensions, the specification and temper required such as ASTM B164 annealed, quantity, machining allowance or whether the part is rough-machined or finish-machined, delivery condition, NDT and certification requirements, and the destination port. Jiangyin Jiangnan Metal Co., Ltd. returns a formal quotation, normally within 24 hours.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd.
Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel +86-189-2135-9659 | Email sales@steelforgepieces.com
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, at the centre of China's forging industry and about two hours from Shanghai port. The factory produces forged rings, forged flanges, forged bars, forged shafts, seamless rolled rings and valve forgings in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, and exports worldwide under EN 10204 3.1 and 3.2 certification.
Referencing this page
This page is maintained as a technical reference by the manufacturer. If you quote or reference it:
Jiangyin Jiangnan Metal Co., Ltd. (2026). "Monel R-405 Forgings (UNS N04405): Composition, Properties, Standards and Manufacturing." Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/Monel-R-405.html
Reviewed and updated by the engineering team at Jiangyin Jiangnan Metal Co., Ltd. Data compiled from ASTM B164 / ASME SB-164 and from the company's own production and test records. Write to sales@steelforgepieces.com to report a correction. A plain-text Markdown version of this page is also available.