Monel 400 PlateASTM B127 UNS N04400 · Manufacturer, trader & exporter, India
Also sold as Alloy 400 · UNS N04400 · W.Nr 2.4360 · Nicorros
Monel 400 plate is Alloy 400 (UNS N04400) rolled to 3/16" (4.76 mm) thickness and above for pressure parts, heavy sections and cut blanks under ASTM B127. It is a nickel–copper alloy, chosen for seawater, hydrofluoric acid and marine service. Kanak Steel & Engineering Co. manufactures, trades and exports it from Mumbai; EN 10204 3.1 or 3.2 certificates are available on request / as specified in the PO. Markets we have supplied to include Oman, UAE, Saudi Arabia, Brazil, Argentina, Spain and Chile (India is the home market).
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- NACE MR0175 on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is Monel 400 Plate?
Monel 400 plate is a nickel–copper alloy supplied as plate to ASTM B127 (UNS N04400). Buyers specify it for seawater, hydrofluoric acid and marine service. It is also sold as Alloy 400, UNS N04400, W.Nr 2.4360.
- What it is
- Nickel–copper alloy
- Standard
- ASTM B127
- Thickness
- 3/16" (4.76 mm) and above
- Density
- 8.8 g/cm³
- Supplied as
- Annealed · HRAP · cut to size
- Best at
- Seawater, hydrofluoric acid and marine service
Monel 400 Plate Specification & Sizes
| Material standard | ASTM B127 · ASME SB-127 |
|---|---|
| General requirements | ASTM B906 — dimensions, tolerances and finishes |
| Grade | Monel 400 · UNS N04400 · W.Nr 2.4360 |
| Thickness | 3/16" (4.76 mm) and above — thinner is sheet |
| Width × length | 1000 / 1250 / 1500 / 2000 / 2500 mm × up to 6000 mm, or cut to drawing |
| Condition & finish | Annealed · hot rolled, annealed & pickled (No.1) |
| Cutting | Cut to size — rectangles, strips, circles & rings |
| Testing | PMI · UT (plate) · intergranular corrosion · hardness, on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection · packing list · certificate of origin |
Sheet or plate?
Both are ordered under ASTM B127, so buyers often mix them up. The line is thickness: below 3/16" is sheet, 3/16" and over is plate. If your drawing calls for under 3/16" (4.76 mm), you need Monel 400 sheet; for 4.76 mm and up, you are in the right place.
Monel 400 Plate Cut to Size
Most 400 plate leaves us as pieces, not full mill plates. Cutting from a full plate means you pay only for what you use, and each piece keeps the heat number of the plate it came from.
| Full & part plates | Full mill plates, halves and quarters |
|---|---|
| Rectangles & strips | To your list of finished sizes, or to a drawing |
| Circles & rings | Blanks for blind flanges, covers, tube sheets and nozzles |
| Machining allowance | State finished size and allowance; thermally cut edges are normally machined back |
| Traceability | Heat number transferred to every piece before cutting |
Send a cutting list or DXF; we nest pieces to reduce off-cut and quote per piece.
Monel 400 Plate Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel (+Co) | As specified |
| Copper | As specified |
| Iron | As specified |
| Manganese | As specified |
| Carbon | As specified |
| Silicon | As specified |
| Sulphur | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM B127 for UNS N04400.
Monel 400 Plate Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM B127 for UNS N04400 — Annealed plate.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8.8 g/cm³ |
| Melting range | 1300 – 1350 °C |
| Magnetic | Slightly magnetic at room temperature |
Monel 400 Equivalent Grades
Monel 400 Plate Weight Chart & Calculator
Use this to budget freight and price per piece. Weight (kg) = length (m) × width (m) × thickness (mm) × 8.8.
Example: 2000 × 1000 × 10 mm
2.0 × 1.0 × 10 × 8.8 = 176.0 kg
Total weight —
| Thickness | 2000 × 1000 plate | Per m² |
|---|---|---|
| 5 mm | 88.0 kg | 44.0 kg |
| 6 mm | 105.6 kg | 52.8 kg |
| 8 mm | 140.8 kg | 70.4 kg |
| 10 mm | 176.0 kg | 88.0 kg |
| 12 mm | 211.2 kg | 105.6 kg |
| 16 mm | 281.6 kg | 140.8 kg |
| 20 mm | 352.0 kg | 176.0 kg |
| 25 mm | 440.0 kg | 220.0 kg |
Six-digit Harmonized System heading (nickel alloy, chapter 75). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify Monel 400 Plate with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. Monel 400 is most often mixed up with Monel K500 — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen; those come from the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | Monel 400 | Monel K500 |
|---|---|---|
| Nickel | As specified | As specified |
| Copper | As specified | As specified |
| Titanium | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
Monel 400 Plate Price — What Decides It
Two quotes for "400 plate" can differ by 20% and both be fair. We quote 400 plate per kg for full sizes and per piece for cut sizes. These six things move the price per kg, so you can compare offers like for like.
Monel 400 Plate Testing & Inspection
Plate goes into pressure parts and heavy sections, so it is inspected for internal soundness and flatness as well as chemistry. These tests are added to the order and reported on the certificate or as separate reports.
| Ultrasonic testing | Straight-beam UT to ASTM A578 (levels A, B or C; plate 10 mm and over, applied to nickel alloys by agreement) or EN 10160 (S0–S3 body, E0–E4 edge classes) |
|---|---|
| Flatness & dimensions | Per ASTM B906 tables for thickness, width and length |
| Corrosion testing | As your specification requires — commonly ASTM G28, Method A (e.g. 625) or Method B (e.g. C276, C22) |
| PMI | Alloy verification on each plate, or each cut piece if required |
| Third-party inspection | Witness by your inspector or agency, with an EN 10204 3.2 certificate |
UT checks the plate body along a scan grid and a band along each edge, where laminations matter most for welding.
Monel 400 Plate Applications
Plate is chosen for pressure-bearing walls, heavy sections and parts machined from solid. For linings, bellows and pressed parts, see Monel 400 sheet.
Monel 400 Plate vs 625, 2507 and 316L
| Grade | Plate standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Monel 400 | ASTM B127 | — | Seawater, hydrofluoric acid and marine service |
| SS 316 / 316L | ASTM A240 | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| Super Duplex 2507 | ASTM A240 | ≈ 42 | Seawater and high-chloride service where strength also matters |
| Inconel 625 | ASTM B443 | ≈ 51 | Seawater, high strength and high temperature in one alloy |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
Monel 400 Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 400 fits.
Very low corrosion rates in flowing seawater and brackish water.
One of the few alloys that handles hydrofluoric acid in all concentrations (air-free).
Resists caustic alkalis and chloride stress-corrosion cracking.
Avoid nitric acid, aerated ammonia and oxidising salts.
How your 400 plate order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI can be arranged depending on product and requirements, as specified in the PO.
- 03Processing — cutting to your sizes, with heat numbers transferred where the PO requires it.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Standards on this page
Fabricating Heavy Monel 400 Plate
Shells, heads and tube sheets mean thick sections and multi-pass welds. These are the points that decide whether 400 plate keeps its corrosion resistance after fabrication; matching filler is ERNiCu-7 (AWS A5.14).
General guidance only; follow your approved WPS, PQR and design code.
| Joint preparation | Bevel above about 2.4 mm, with a wider included angle (around 80°) and thinner land than for steel — nickel weld pools do not flow far. |
|---|---|
| Interpass temperature | Keep it low — typically 93 °C (200 °F) maximum for Ni-Cr-Mo alloys such as C276, C22 and 625; follow your WPS for other nickel alloys. No preheat on clean, dry plate. |
| Cleanliness | Remove grease, paint, marking crayon and sulphur-bearing compounds before welding or heat treatment. |
| Machining | Nickel alloys work-harden: carbide tools, positive rake, low speed and a feed heavy enough to cut under the hardened layer. |
How to Order Monel 400 Plate: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Standard and edition — e.g. ASTM B127-latest
- Thickness × width × length, and number of pieces
- Full plates or cut pieces (attach drawing)
- Certificate type — 3.1 or 3.2, and the inspection agency
- Extra tests — NACE, UT, intergranular corrosion
- Delivery port, Incoterm and required date
Monel 400 plate — questions buyers ask
Is Monel 400 the same as Alloy 400?
Alloy 400, UNS N04400, W.Nr 2.4360 are names used for Monel 400 (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order), and plate is ordered to ASTM B127 whichever name is on the enquiry.
What thickness counts as Monel 400 plate?
Under ASTM B127 and its general-requirements standard, flat material below 3/16" (4.76 mm) is sheet (or strip if narrower than 24") and 3/16" (4.76 mm) and over is plate. Order the form that matches your drawing thickness.
What is the price of Monel 400 plate per kg?
It moves with nickel on the LME, so a fixed list price is out of date within days. Thickness, cut size, quantity and documents also change it. Send your size and quantity and we quote the same working day.
Do you supply ultrasonically tested Monel 400 plate?
Yes, UT can be added to the order — to ASTM A578 or the level your specification states. The UT report is supplied with the mill certificate.
Can Monel 400 plate be cut into circles and rings?
Yes. Blanks for blind flanges, covers and tube sheets are cut from plate to your drawing, with the heat number marked on every piece.
What machining allowance should I leave on cut plate?
It depends on the cutting method and finished tolerance. Give us the finished size and your allowance; thermally cut edges are normally machined back to sound metal.
How heavy is a Monel 400 plate?
Weight (kg) = length (m) × width (m) × thickness (mm) × 8.8. A 2000 × 1000 × 10 mm plate weighs about 176 kg; use the calculator on this page for your size.
What documents come with an export shipment?
An EN 10204 3.1 mill certificate (or 3.2 with a third-party inspector), commercial invoice, packing list with heat numbers, and certificate of origin. Test reports are added for any extra tests ordered.
Can Monel 400 plate be supplied to NACE MR0175?
Monel 400 (UNS N04400) can be supplied for sour service when the PO specifies NACE MR0175 / ISO 15156; acceptability depends on the material condition, hardness and the environmental limits in that standard, which the purchaser must confirm for the application.
Monel 400 or SS 316 / 316L — which should I choose?
Monel 400 is chosen for seawater, hydrofluoric acid and marine service. SS 316 / 316L is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026