Monel K500 FlangesASTM B865 UNS N05500 · Manufacturer, stockist & exporter, India
Also sold as Alloy K-500 · UNS N05500 · W.Nr 2.4375 · Age-hardened Monel
Monel K500 flanges are forged to ASTM B865 and machined to ASME B16.5 (½"–24", Class 150–2500) or ASME B16.47 for larger sizes. It is a age-hardenable nickel–copper alloy with aluminium and titanium, chosen for high-strength pump shafts, bolting and springs in seawater. 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 K500 Flanges?
Monel K500 flanges is an age-hardenable nickel–copper alloy with aluminium and titanium supplied as flanges to ASTM B865 (UNS N05500). Buyers specify it for high-strength pump shafts, bolting and springs in seawater. It is also sold as Alloy K-500, UNS N05500, W.Nr 2.4375.
- What it is
- Age-hardenable nickel–copper alloy with aluminium and titanium
- Material
- ASTM B865
- Dimensions
- ASME B16.5 · B16.47 · EN 1092-1
- Classes
- 150 · 300 · 600 · 900 · 1500 · 2500
- Facing
- RF · FF · RTJ
- Best at
- High-strength pump shafts, bolting and springs in seawater
Monel K500 Flanges Specification & Sizes
| Material standard | ASTM B865 |
|---|---|
| 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 K500 Flange Pressure–Temperature Rating
The class is not a pressure: the allowable pressure for K500 flanges comes from the ASME B16.5 table for its material group, and falls as temperature rises (how ratings work). Check the material group for ASTM B865 in B16.5 Table 1A before choosing the class.
Take the actual pressures from the B16.5 rating table for group listed for your material; your piping class sheet governs.
Bolting & Gaskets for K500 Flanges
For Monel K500 flanges the usual bolting is B7 (coated), B8M or nickel-alloy studs such as Monel K500 from ASTM B865, as the project specifies — see Monel K500 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 K500 Flanges Chemical Composition
| Element | Weight % |
|---|---|
| Nickel (+Co) | 63.0 min |
| Copper | 27.0 – 33.0 |
| Aluminium | 2.30 – 3.15 |
| Titanium | 0.35 – 0.85 |
| Iron | 2.0 max |
| Manganese | 1.5 max |
| Carbon | 0.25 max |
| Silicon | 0.5 max |
Monel K500 Flanges Mechanical Properties
| Age-hardened bar | Value |
|---|---|
| Tensile strength | 965 MPa · 140 ksi |
| Yield strength 0.2% | 690 MPa · 100 ksi |
| Elongation | 20% |
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8.44 g/cm³ |
| Melting range | 1315 – 1350 °C |
| Magnetic | Non-magnetic to about −100 °C |
Monel K500 Equivalent Grades
Values follow ASTM B865 for UNS N05500. Always check against the edition named on your purchase order.
Monel K500 flange dimensions — ASME B16.5 Class 150 & 300
Outside dimensions depend only on size and class, not on the alloy, so K500 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 K500 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 K500 is most often mixed up with Monel 400 — 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 K500 | Monel 400 |
|---|---|---|
| Nickel | 63.0 min | 63.0 min |
| Copper | 27.0 – 33.0 | 28.0 – 34.0 |
| Titanium | 0.35 – 0.85 | residual |
| Iron | 2.0 max | 2.5 max |
| Manganese | 1.5 max | 2.0 max |
Monel K500 Flanges Price — What Decides It
Two quotes for "K500 flanges" can differ by 20% and both be fair. We quote K500 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 K500 flanges by type
Monel K500 Flanges Applications
Monel K500 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 K500 Flanges vs 400, 718 and 2507
| Grade | Flanges standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Monel 400 | ASTM B564 | — | Seawater, hydrofluoric acid and marine service |
| Inconel 718 | ASTM B637 | — | Very high strength at temperatures up to about 650 °C |
| Monel K500 | ASTM B865 | — | High-strength pump shafts, bolting and springs in seawater |
| Super Duplex 2507 | ASTM A182 F53 | ≈ 42 | Seawater and high-chloride service where strength also matters |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
Monel K500 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 K500 fits.
Aluminium and titanium let K500 be age-hardened to about three times the strength of Monel 400.
Keeps the seawater corrosion resistance of Monel 400.
Chosen where a part needs strength and seawater resistance together.
In sour service, check hardness limits in NACE MR0175 before specifying.
How your K500 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 K500 Flanges
Monel K500 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiCu-7 (non-ageing) |
|---|---|
| Over-alloyed filler | Weld in the annealed condition, then age |
| 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.
How to Order Monel K500 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 K500 flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiMonel K500 flanges — questions buyers ask
Is Monel K500 the same as Alloy K-500?
Yes. Alloy K-500, UNS N05500, W.Nr 2.4375 all refer to the same material, and flanges is ordered to ASTM B865 whichever name is on the enquiry.
Which standard covers Monel K500 flanges?
ASTM B865 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 K500 Class 300 flange take?
It depends on temperature and the material group of ASTM B865 in ASME B16.5; read the Class 300 column of that group's rating table at your design temperature.
Which bolts should I use with Monel K500 flanges?
Usually B7 (coated), B8M or nickel-alloy studs such as Monel K500 from ASTM B865, as the project specifies. In corrosive or sour service the bolting material is set by the project specification.
Can a Monel K500 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 K500 flanges to NACE MR0175?
Yes. Monel K500 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 K500 or Super Duplex 2507 — which should I choose?
Monel K500 is chosen for high-strength pump shafts, bolting and springs in seawater. Super Duplex 2507 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