Monel 400 round bar is a robust nickel-copper alloy (UNS N04400) that combines exceptional resistance to seawater, many acids and alkalis, and reliable mechanical strength from cryogenic temperatures up to about 538 °C (1000 °F). if your project needs a corrosion-resistant, weldable bar for shafts, valves, fasteners or chemical equipment that will survive aggressive chloride environments and heavy mechanical loading, Monel 400 round bar is one of the best balanced choices. MWalloys supplies Monel 400 round bars from our China works at 100% factory pricing with rapid stock delivery for standard sizes and mill certification on request.
1) What is Monel 400?
Monel 400 is a single-phase nickel-copper alloy whose principal elements are nickel (majority) and copper (about one third). It is a solid solution alloy that gains strength mainly through cold work rather than heat treatment. The alloy is prized for long-term service in salt water, steam, and many chemical environments because it resists general corrosion, pitting and crevice attack under many conditions. Monel 400 is widely used where corrosion resistance and toughness are required together.
2) Chemical composition (typical limits)
Below is a compact table showing the standard composition ranges commonly used for Monel 400 (UNS N04400). Values are percent by weight and represent the conventional commercial specification limits.
| Element | Typical / Spec range (wt%) |
|---|---|
| Nickel (Ni) | Balance (≈ 63–70 %) |
| Copper (Cu) | 28–34 |
| Iron (Fe) | ≤ 2.5 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 0.50 |
| Carbon (C) | ≤ 0.30 |
| Sulfur (S) | ≤ 0.024 |
| Cobalt (Co) | ≤ 1.0 (trace in some specs) |
(These composition limits follow the published datasheets for Monel 400 and standard supplier chemistry tables.)
3) Physical and mechanical properties
The following table collects the most useful design numbers engineers request for bar sizing, strength and thermal design. Values are representative; always use mill test certificate values for final design.
| Property | Typical value (annealed) |
|---|---|
| Density | ≈ 8.8 g/cm³ (0.318 lb/in³). |
| Melting range | ≈ 1290–1350 °C (range depends on exact chemistry). |
| Tensile strength (ultimate) | ~ 550 MPa (approx. 80–85 ksi) — supplier/size dependent. |
| Yield strength (0.2% offset) | ~ 240 MPa (approx. 35 ksi) typical annealed. |
| Elongation (in 50 mm) | ~ 30–60% (good ductility) |
| Hardness (HB) | Annealed: ~ 120–200 HB depending on product and mill finish |
| Modulus of elasticity | ~ 179 GPa |
| Thermal conductivity | Moderate — lower than copper, higher than stainless steels |
| Useful temperature range | Sub-zero up to ~ 538 °C / 1000 °F for many applications. |
| Magnetic behavior | Slightly magnetic in the annealed state |
Notes: property values vary with product form, manufacturing process and cold work level. For precise design limits use the mill test data supplied with the shipped material.
4) Standards, specifications and typical document references
Common industry standards for Monel 400 round bar include:
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ASTM B164 / ASME SB164: Standard specification for nickel-copper alloy rod, bar and wire (used by many mills and stockists).
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UNS N04400: Unified Numbering System designation for Monel 400.
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Werkstoff Nr. 2.4360 / 2.4361: European material numbers used in EN / DIN cross references.
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NACE ISO recommendations: Monel 400 is well referenced for oil and gas splash-zone and sour service when correctly selected and tested.
When specifying bars, buyers typically note the standard (ASTM B164 or equivalent), required heat treatment/tempering, mill test report (MTR / EN 10204 3.1 or 3.2), requested tolerances, and any additional testing such as hardness, PMI or ultrasonic exam.
5) Monel 400 round bar specification sizes, tolerances and finishes
Manufacturers and stockists offer Monel 400 round bars in a broad diameter range. Common industrial sizes and finishes include:
| Feature | Typical options |
|---|---|
| Diameters | 3 mm up to 495 mm or larger (varies by mill). Typical stocked: 6, 8, 10, 12, 16, 20, 25, 30, 40, 50, 60, 80, 100 mm. |
| Lengths | Standard cut lengths 1 m to 6 m; mill lengths up to 12 m; cut-to-length service available. |
| Tolerances | H8, H9 etc. or per ASTM B164 / customer drawing. |
| Finishes | Bright turned, cold drawn, centerless ground, polished, black (as forged) |
| Forms available | Solid round, hollow bar, hex, square, flat bar, threaded bar, precision ground bars. |
Specification table (example for ordering):
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Material: Monel 400, UNS N04400, ASTM B164
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Size: Ø XX mm × length mm
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Quantity: X pcs or weight (kg)
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Delivery condition: annealed / stress relieved per ASTM B164 clause [if required]
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Mill test report: EN 10204 3.1 / 3.2 required: Yes/No
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Surface finish: centerless ground / turned
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Packaging: wooden crate, oil coated, desiccant if required
6) Manufacturing, bar forming and finishing processes
Monel 400 round bars are produced through standard nonferrous steel mill processes adapted to nickel-copper metallurgy:
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Melting and refining: typically induction or vacuum induction melting to produce homogenous alloy.
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Casting: continuous cast billets or ingots sized for further rolling or forging.
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Hot working: hot extrusion, hot rolling or forging to produce bar blanks. Controlled hot deformation ensures good grain structure and workability.
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Cold drawing / turning: optional cold drawing or turning to achieve precise diameters and improve surface finish and mechanical properties via strain hardening.
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Heat treatment / stress relief: Monel 400 is not precipitation-hardening; anneal or stress relieve as required by specification, commonly a stress relief at around 1100 °F (600 °C) for certain bar products.
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Grinding / centerless finish: precision ground bars for tight tolerance applications.
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Inspection and certification: dimensional controls, chemical analysis, mechanical testing, MTR issuance and NDT if required.
Practical note: because Monel 400 gains strength only by cold work, many shaft and fastener applications are supplied in a slightly cold worked or drawn condition to deliver higher yield and hardness.
7) Monel 400 equivalents and cross references
Common cross references and trade names you will see in procurement:
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UNS N04400: universal designation.
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W. Nr. (Werkstoff) 2.4360 / 2.4361: German/European number.
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Trade names: Monel® 400 (Special Metals), Alloy 400, Nickel-Copper 65-35 (approximate ratio naming)
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Nearby alloys: Monel R-405 (a free-machining variant), Monel K-500 (precipitation-hardening version for higher strength but different corrosion behavior). Always check cross-reference tables before substituting because K-500 is strengthened differently.
8) Common uses and industry examples
Monel 400 round bar finds regular use where corrosion and mechanical performance must coexist:
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Marine engineering: pump and propeller shafts, nuts, bolts and fittings exposed to seawater. Monel 400 resists erosion and cavitation in flowing sea water.
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Chemical processing: valves, valve stems, pump components, heat exchanger rods, equipment that sees chloride or acidic environments.
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Oil & gas: riser and splash-zone cladding, components in sour service when specifically qualified.
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Power generation and desalination: elements exposed to brackish or hot seawater.
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Aerospace and instrumentation: where corrosion resistance and thermal properties are necessary in compact parts.
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Architectural and decorative: historical use for aesthetic patinas and long life in outdoor exposures.
Case example: Monel 400 cladding or sheathing has a long service history on offshore structures for splash zone protection — selected because of low corrosion rates under marine conditions and mechanical robustness in impact situations.
9) Sizes and weight chart (quick reference)
Use the density 8.8 g/cm³ for calculation. The following is a practical weight chart in kg per metre for common diameters of solid Monel 400 round bar. (Formula used: mass(kg/m) = density (g/cm³) × area(cm²) × 0.1)
| Diameter (mm) | Mass (kg / m) |
|---|---|
| 6 | 0.2488 |
| 8 | 0.4423 |
| 10 | 0.6912 |
| 12 | 0.9953 |
| 16 | 1.7693 |
| 20 | 2.7646 |
| 25 | 4.3197 |
| 30 | 6.2204 |
| 40 | 11.0584 |
| 50 | 17.2788 |
| 60 | 24.8814 |
| 80 | 44.2336 |
| 100 | 69.1150 |
| 150 | 155.5088 |
| 200 | 276.4602 |
(These figures are rounded to 4 decimal places for convenience. Use exact MTR density and precise diameter tolerance for final order quantity calculation.) — computed from standard density figures.
10) Monel 400 bar price 2025
Short summary: Monel 400 remains a premium nonferrous alloy because of its nickel content and specialized production route. Prices fluctuate with nickel and copper metal markets, certification needs, lot size and form (bar vs. plate vs. wire). Below is a market snapshot for 2025 expressed as USD per kilogram typical factory / mill or stockist ranges observed in Q2–Q3 2025.
| Region | Typical price range (USD / kg) — 2025 snapshot | Notes |
|---|---|---|
| China (export/mill prices) | $28 – $45 / kg | Competitive factory/ex-works quotes for standard bar stock. Lower end applies to large volume, non-certified packs. |
| United States | $45 – $65 / kg | Higher due to domestic production costs, inventory overhead and certification. |
| Europe | $48 – $67 / kg | Higher still when REACH compliance, CE/EN marking or special testing is required. |
What influences these ranges
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Nickel and copper commodity pricing and LME moves.
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Form factor: bars typically cost more per kg than plate in small orders.
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Certification: EN 10204 Type 3.1/3.2 tests and piping/pressure certifications add cost.
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Finish and special machining: precision ground, cold-drawn or small diameters push price upward.
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Order quantity and logistics: small MOQ and air freight increase per-kg prices.
Market note: because Monel 400 is nickel-rich, any rapid movement in nickel contracts shifts the alloy price quickly. For project budgeting we recommend asking suppliers for a 7–14 day firm quote and confirming MTR inclusion.
11) Fabrication notes: machining, welding, cold work and heat treatment
Practical pointers for workshop use:
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Machining: Monel 400 machines reasonably well compared to many high-nickel alloys. Use sharp carbide tooling, positive rake angles, and moderate cutting speeds. Chip control can be improved by small depth of cut and good coolant. Consider using free-machining Monel R-405 for high-volume turned parts.
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Welding: Monel 400 welds readily by most fusion processes. Use matching electrodes/filler metals and control heat input. For critical pressure or sour service, follow accepted welding procedure specifications and post-weld inspection routines.
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Heat treatment: Monel 400 cannot be strengthened by conventional heat treatments; strength increases are achieved by cold working. Solution annealing is not a common strengthening path. Stress relief can be applied if specified by the buyer.
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Cold work: Cold drawing or cold rolling raises yield and tensile strength; factor this into forming and assembly operations.
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Corrosion testing: For service in chloride environments, run project-specific corrosion tests, crevice cell tests or follow NACE recommendations for sour or oilfield environments.
12) Storage, ordering, marking and packaging
When placing a purchase order include the following to minimize misunderstandings:
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Material name and UNS: Monel 400, UNS N04400
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Standard: ASTM B164 / ASME SB164 or equivalent.
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Size and tolerance: e.g., Ø 25 mm ±0.1 mm, length 3000 mm ± 2 mm
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Condition: annealed / stress relieved / cold worked
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Required documentation: MTR (EN 10204 3.1), chemical and mechanical test report, PMI if required
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Special tests: hardness, PMI, dye penetrant, ultrasonic or other non-destructive tests
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Surface finish and packaging instructions: oil coating, wrapped, wooden crates, desiccant for long sea transit
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Delivery terms: EXW / FOB / CIF and expected lead time — indicate urgent stock request if required
MWAlloys can supply directly from stock or mill with full MTRs and can mark and package to buyer specifications.
Monel 400 is used in many regulated industries. Typical compliance and certification items to check:
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NACE / ISO references for sour service and oil and gas. Monel 400 is included in many NACE guidance documents where proper selection criteria are fulfilled.
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ASTM standards — specify ASTM B164 for bar product acceptance.
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REACH / RoHS — European end users sometimes require REACH declarations for heavy metals; costs for conformity impact European prices.
14) Frequently Asked Questions (FAQ)
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Q: Is Monel 400 better than 316 stainless steel for seawater service?
A: In many seawater and splash-zone applications, Monel 400 outperforms 316 in resistance to pitting and erosion under rapid flow. However, choose materials by detailed environmental data and cost tradeoffs. -
Q: Can Monel 400 be hardened by heat treatment?
A: No. Monel 400 is strengthened by cold work only. For higher strength with similar corrosion resistance consider Monel K-500 (which is precipitation hardenable) but note K-500 has different corrosion behavior. -
Q: What drawings/specification should I put in my PO for shafts?
A: Specify UNS N04400, ASTM B164, diameter tolerance (H9/H8), required length, MTR type (3.1/3.2), finish and any special inspection. -
Q: Are Monel 400 bars magnetic?
A: Slightly magnetic in the annealed condition; some cold work increases magnetic response. -
Q: What are typical delivery times?
A: If bars are in stock, MWalloys can dispatch within days. For mill runs, 2–6 weeks depending on order size and certification. (Confirm on quotation.) -
Q: Can I weld Monel 400 to carbon steel?
A: Yes, with appropriate filler metal and joint design. Use qualified weld procedures and consider galvanic and corrosion compatibility. -
Q: How should I calculate weight for ordering?
A: Use density 8.8 g/cm³ and the cross sectional area. (See the weight table earlier for common diameters.) ASM -
Q: Are there cheaper alternatives?
A: In many cases 90–10 Cu-Ni, duplex stainless steels or chrome-nickel alloys may be used, but each has distinct corrosion limits. Evaluate environment, strength and cost before substituting. -
Q: Does Monel 400 resist hydrochloric acid?
A: It performs well in de-aerated hydrochloric environments under certain conditions, but oxidizing or aerated HCl is more aggressive. Run specific corrosion testing for design. -
Q: Where can I get certified stock and fast delivery?
A: MWalloys maintains stock and offers 100% factory price direct supply with fast dispatch for typical bar sizes. See our product page or request a formal quote.
15) Why buy Monel 400 round bar from MWalloys
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Factory direct pricing: MWalloys supplies Monel 400 round bars at 100% factory prices from our Chinese mills and stock, giving global buyers competitive per-kg rates.
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Fast stock delivery: We hold common sizes in inventory for rapid shipment.
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Full documentation: Mill test reports, chemical and mechanical certificates, and traceability for each batch.
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Custom services: Cut-to-length, end machining, surface finishing and packaging per customer requirements.
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Technical support: Our metallurgical engineers advise on alloy selection, fabrication techniques and inspection plans.
If you have a bill of materials or part drawing, send it to MWalloys and we will provide a factory quote with lead time, MTR options and CIF/FOB logistics.
16) Authoritative references
- Special Metals Corporation — MONEL® Alloy 400 Technical Bulletin (datasheet, composition and properties)
- ASM International — Alloy Digest: MONEL alloy 400 (material digest and metallurgy)
- Nickel Institute — Properties of Some Metals and Alloys (reference data and marine guidance)
- ASTM International — B164 Standard Specification for Nickel-Copper Alloy Rod, Bar, and Wire (purchase / abstract page)
