Monel 400 FlangesASTM B564 UNS N04400 · Manufacturer, stockist & exporter, India
Also sold as Alloy 400 · UNS N04400 · W.Nr 2.4360 · Nicorros
Monel 400 flanges are forged to ASTM B564 and machined to ASME B16.5 (½"–24", Class 150–2500) or ASME B16.47 for larger sizes. It is a nickel–copper alloy, chosen for seawater, hydrofluoric acid and marine service. Kanak Steel & Engineering Co. supplies it with EN 10204 3.1 mill certificates from Mumbai to buyers across India, the Gulf, South-East Asia, South America, Europe, the UK and the USA.
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on every heat
- NACE MR0175 on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is Monel 400 Flanges?
Monel 400 flanges is a nickel–copper alloy supplied as flanges to ASTM B564 (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
- Material
- ASTM B564
- Dimensions
- ASME B16.5 · B16.47 · EN 1092-1
- Classes
- 150 · 300 · 600 · 900 · 1500 · 2500
- Facing
- RF · FF · RTJ
- Best at
- Seawater, hydrofluoric acid and marine service
Monel 400 Flanges Specification & Sizes
| Material standard | ASTM B564 |
|---|---|
| Dimensional standards | ASME B16.5 (½"–24") · B16.47 Series A / B (26"–60") · B16.36 orifice · B16.48 line blanks · EN 1092-1 |
| Pressure classes | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | Raised face (RF) · flat face (FF) · ring type joint (RTJ) · tongue & groove |
| Bore | To match the pipe schedule — specify it on the order |
| Types | Weld neck flange · Slip-on flange · Blind flange · Socket weld flange · Threaded flange · Lap joint flange · Long weld neck flange · Orifice flange · Spectacle blind · Reducing flange · Ring type joint flange · Expander flange · Anchor flange · Swivel ring flange |
| Testing | PMI · dimensional · UT of forgings · IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
Standards on this page
Monel 400 Flange Pressure–Temperature Rating
The class is not a pressure: the allowable pressure for 400 flanges comes from the ASME B16.5 table for its material group, and falls as temperature rises (how ratings work). ASTM B564 is in material group 3.4.
Take the actual pressures from the B16.5 rating table for group 3.4. A class is not a project pressure rating — your piping class sheet and design conditions govern.
Bolting & Gaskets for 400 Flanges
For Monel 400 flanges the usual bolting is B7 (coated), B8M or nickel-alloy studs such as Monel 400 from ASTM B164, as the project specifies — see Monel 400 fasteners. Spiral-wound gaskets for this service usually use a winding in the same or a higher alloy, so the gasket does not corrode first. Facing and gasket options are compared in the flange guide.
Monel 400 Flanges Chemical Composition
| Element | Weight % |
|---|---|
| Nickel (+Co) | 63.0 min |
| Copper | 28.0 – 34.0 |
| Iron | 2.5 max |
| Manganese | 2.0 max |
| Carbon | 0.3 max |
| Silicon | 0.5 max |
| Sulphur | 0.024 max |
Monel 400 Flanges Mechanical Properties
| Annealed plate | Value |
|---|---|
| Tensile strength | 480 MPa · 70 ksi |
| Yield strength 0.2% | 195 MPa · 28 ksi |
| Elongation | 35% |
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
Values follow ASTM B127 for UNS N04400. Always check against the edition named on your purchase order.
Monel 400 flange dimensions — ASME B16.5 Class 150 & 300
Outside dimensions depend only on size and class, not on the alloy, so 400 flanges bolt to any B16.5 flange of the same size and class. Values in mm; thickness excludes the 1.6 mm raised face.
| NPS | Cl 150 OD | Cl 150 thickness | Cl 150 bolt circle | Cl 150 bolts | Cl 300 OD | Cl 300 thickness | Cl 300 bolt circle | Cl 300 bolts |
|---|---|---|---|---|---|---|---|---|
| ½" | 90 | 9.6 | 60.3 | 4 × ½" | 95 | 12.7 | 66.7 | 4 × ½" |
| 1" | 110 | 12.7 | 79.4 | 4 × ½" | 125 | 15.9 | 88.9 | 4 × ⅝" |
| 1½" | 125 | 15.9 | 98.4 | 4 × ½" | 155 | 19.1 | 114.3 | 4 × ¾" |
| 2" | 150 | 17.5 | 120.7 | 4 × ⅝" | 165 | 20.7 | 127.0 | 8 × ⅝" |
| 3" | 190 | 22.3 | 152.4 | 4 × ⅝" | 210 | 27.0 | 168.3 | 8 × ¾" |
| 4" | 230 | 22.3 | 190.5 | 8 × ⅝" | 255 | 30.2 | 200.0 | 8 × ¾" |
| 6" | 280 | 23.9 | 241.3 | 8 × ¾" | 320 | 35.0 | 269.9 | 12 × ¾" |
| 8" | 345 | 27.0 | 298.5 | 8 × ¾" | 380 | 39.7 | 330.2 | 12 × ⅞" |
| 10" | 405 | 28.6 | 362.0 | 12 × ⅞" | 445 | 46.1 | 387.4 | 16 × 1" |
| 12" | 485 | 30.2 | 431.8 | 12 × ⅞" | 520 | 49.3 | 450.8 | 16 × 1⅛" |
Full chart: ASME B16.5 flange dimensions.
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 Flanges 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. We PMI-test nickel alloys as standard and any grade on request.
| Element | Monel 400 | Monel K500 |
|---|---|---|
| Nickel | 63.0 min | 63.0 min |
| Copper | 28.0 – 34.0 | 27.0 – 33.0 |
| Titanium | residual | 0.35 – 0.85 |
| Iron | 2.5 max | 2.0 max |
| Manganese | 2.0 max | 1.5 max |
Monel 400 Flanges Price — What Decides It
Two quotes for "400 flanges" can differ by 20% and both be fair. We quote 400 flanges 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 flanges by type
Monel 400 Flanges Applications
Monel 400 is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
Monel 400 Flanges vs 625, 2507 and 316L
| Grade | Flanges standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Monel 400 | ASTM B564 | — | Seawater, hydrofluoric acid and marine service |
| SS 316 / 316L | ASTM A182 F316L | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| Super Duplex 2507 | ASTM A182 F53 | ≈ 42 | Seawater and high-chloride service where strength also matters |
| Inconel 625 | ASTM B564 | ≈ 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 flanges order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked and material is PMI-tested before processing.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked.
- 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
Welding & Fabricating Monel 400 Flanges
Monel 400 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiCu-7 (AWS A5.14) |
|---|---|
| Over-alloyed filler | ENiCu-7 electrode |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 400 fittings and 400 flanges for the matching pipe-system parts.
How to Order Monel 400 Flanges: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Flange type and dimensional standard (B16.5 / B16.47 / EN 1092-1)
- Size, pressure class and facing
- Bore / schedule for weld neck and socket weld flanges
- Material standard and grade marking
- Certificate type and extra tests
- Delivery port, Incoterm and required date
Monel 400 flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiMonel 400 flanges — questions buyers ask
Is Monel 400 the same as Alloy 400?
Yes. Alloy 400, UNS N04400, W.Nr 2.4360 all refer to the same material, and flanges is ordered to ASTM B564 whichever name is on the enquiry.
Which standard covers Monel 400 flanges?
ASTM B564 is the material specification for the forging; dimensions follow ASME B16.5 for ½"–24" and ASME B16.47 for 26" and above. European projects use EN 1092-1.
What pressure can a Monel 400 Class 300 flange take?
It depends on temperature. ASTM B564 is in ASME B16.5 material group 3.4; read the Class 300 column of that group's table at your design temperature.
Which bolts should I use with Monel 400 flanges?
Usually B7 (coated), B8M or nickel-alloy studs such as Monel 400 from ASTM B164, as the project specifies. In corrosive or sour service the bolting material is set by the project specification.
Can a Monel 400 flange be welded to a different pipe material?
Yes — a nickel-base filler such as ERNiCr-3 (or ERNiCrMo-3) is used when joining it to carbon steel. Weld neck bores must match the mating pipe schedule.
Can you supply Monel 400 flanges to NACE MR0175?
Yes. Monel 400 is listed in NACE MR0175 / ISO 15156-3 for sour service within that standard's environmental limits. State NACE compliance on the order and it is confirmed on the certificate.
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