Inconel 718 FlangesASTM B637 UNS N07718 · Manufacturer, stockist & exporter, India
Also sold as Alloy 718 · UNS N07718 · W.Nr 2.4668 · Precipitation-hardening nickel alloy
Inconel 718 flanges are forged to ASTM B637 and machined to ASME B16.5 (½"–24", Class 150–2500) or ASME B16.47 for larger sizes. It is a age-hardenable nickel–chromium alloy with niobium and molybdenum, chosen for very high strength at temperatures up to about 650 °C. 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 Inconel 718 Flanges?
Inconel 718 flanges is an age-hardenable nickel–chromium alloy with niobium and molybdenum supplied as flanges to ASTM B637 (UNS N07718). Buyers specify it for very high strength at temperatures up to about 650 °C. It is also sold as Alloy 718, UNS N07718, W.Nr 2.4668.
- What it is
- Age-hardenable nickel–chromium alloy with niobium and molybdenum
- Material
- ASTM B637
- Dimensions
- ASME B16.5 · B16.47 · EN 1092-1
- Classes
- 150 · 300 · 600 · 900 · 1500 · 2500
- Facing
- RF · FF · RTJ
- Best at
- Very high strength at temperatures up to about 650 °C
Inconel 718 Flanges Specification & Sizes
| Material standard | ASTM B637 |
|---|---|
| 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
Inconel 718 Flange Pressure–Temperature Rating
The class is not a pressure: the allowable pressure for 718 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 B637 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 718 Flanges
For Inconel 718 flanges the usual bolting is B7 (coated), B8M or nickel-alloy studs such as Inconel 718 from ASTM B637, as the project specifies — see Inconel 718 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.
Inconel 718 Flanges Chemical Composition
| Element | Weight % |
|---|---|
| Nickel (+Co) | 50.0 – 55.0 |
| Chromium | 17.0 – 21.0 |
| Niobium + Tantalum | 4.75 – 5.50 |
| Molybdenum | 2.80 – 3.30 |
| Titanium | 0.65 – 1.15 |
| Aluminium | 0.20 – 0.80 |
| Carbon | 0.08 max |
| Iron | Balance |
Inconel 718 Flanges Mechanical Properties
| Solution-treated and aged | Value |
|---|---|
| Tensile strength | 1275 MPa · 185 ksi |
| Yield strength 0.2% | 1034 MPa · 150 ksi |
| Elongation | 12% |
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8.19 g/cm³ |
| Melting range | 1260 – 1336 °C |
| Magnetic | Non-magnetic |
Inconel 718 Equivalent Grades
Values follow ASTM B637 / B670 for UNS N07718. Always check against the edition named on your purchase order.
Inconel 718 flange dimensions — ASME B16.5 Class 150 & 300
Outside dimensions depend only on size and class, not on the alloy, so 718 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 Inconel 718 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. Inconel 718 is most often mixed up with Inconel 625 — 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 | Inconel 718 | Inconel 625 |
|---|---|---|
| Nickel | 50.0 – 55.0 | 58.0 min |
| Chromium | 17.0 – 21.0 | 20.0 – 23.0 |
| Molybdenum | 2.80 – 3.30 | 8.0 – 10.0 |
| Titanium | 0.65 – 1.15 | 0.40 max |
| Niobium | 4.75 – 5.50 | 3.15 – 4.15 |
| Iron | Balance | 5.0 max |
| Manganese | residual | 0.50 max |
Inconel 718 Flanges Price — What Decides It
Two quotes for "718 flanges" can differ by 20% and both be fair. We quote 718 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.
Inconel 718 flanges by type
Inconel 718 Flanges Applications
Inconel 718 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.
Inconel 718 Flanges vs 625, 600 and 825
| Grade | Flanges standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Inconel 600 | ASTM B564 | — | High-temperature oxidation, caustic and nuclear service |
| Inconel 718 | ASTM B637 | — | Very high strength at temperatures up to about 650 °C |
| Inconel 825 | ASTM B564 | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| 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.
Inconel 718 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 718 fits.
Niobium forms the gamma-double-prime phase that doubles strength after ageing.
Keeps very high strength and creep resistance up to about 650 °C.
Ages slowly, so it can be welded without cracking during post-weld heat treatment.
718 is chosen for strength; for corrosion alone, 625 or 825 are usually better value.
How your 718 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 Inconel 718 Flanges
Inconel 718 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiFeCr-2 (AWS A5.14) |
|---|---|
| Over-alloyed filler | Post-weld solution treatment and ageing restore strength |
| 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 718 fittings and 718 flanges for the matching pipe-system parts.
How to Order Inconel 718 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
Inconel 718 flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiInconel 718 flanges — questions buyers ask
Is Inconel 718 the same as Alloy 718?
Yes. Alloy 718, UNS N07718, W.Nr 2.4668 all refer to the same material, and flanges is ordered to ASTM B637 whichever name is on the enquiry.
Which standard covers Inconel 718 flanges?
ASTM B637 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 Inconel 718 Class 300 flange take?
It depends on temperature and the material group of ASTM B637 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 Inconel 718 flanges?
Usually B7 (coated), B8M or nickel-alloy studs such as Inconel 718 from ASTM B637, as the project specifies. In corrosive or sour service the bolting material is set by the project specification.
Can a Inconel 718 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 Inconel 718 flanges to NACE MR0175?
Yes. Inconel 718 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.
Inconel 718 or Inconel 825 — which should I choose?
Inconel 718 is chosen for very high strength at temperatures up to about 650 °C. Inconel 825 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