Inconel 625 FlangesASTM B564 UNS N06625 · Manufacturer, stockist & exporter, India
Also sold as Alloy 625 · UNS N06625 · W.Nr 2.4856 · Nicrofer 6020
Inconel 625 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–chromium–molybdenum alloy with niobium, chosen for seawater, high strength and high temperature in one alloy. 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 request
- NACE MR0175 on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is Inconel 625 Flanges?
Inconel 625 flanges is a nickel–chromium–molybdenum alloy with niobium supplied as flanges to ASTM B564 (UNS N06625). Buyers specify it for seawater, high strength and high temperature in one alloy. It is also sold as Alloy 625, UNS N06625, W.Nr 2.4856.
- What it is
- Nickel–chromium–molybdenum alloy with niobium
- 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, high strength and high temperature in one alloy
Inconel 625 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 |
Inconel 625 Flange Pressure–Temperature Rating
The class is not a pressure: the allowable pressure for 625 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 3.8.
Take the actual pressures from the B16.5 rating table for group 3.8. A class is not a project pressure rating — your piping class sheet and design conditions govern.
Bolting & Gaskets for 625 Flanges
For Inconel 625 flanges the usual bolting is B7 (coated), B8M or nickel-alloy studs in Inconel 625 (bar to ASTM B446, where applicable), as the project specifies — see Inconel 625 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.
Where Inconel 625 Flanges Are Used
Inconel 625 Flanges Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel | As specified |
| Chromium | As specified |
| Molybdenum | As specified |
| Niobium + Tantalum | As specified |
| Iron | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Titanium | As specified |
| Aluminium | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM B443 for UNS N06625.
Inconel 625 Flanges 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 B443 for UNS N06625 — Grade 1 annealed plate.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8.44 g/cm³ |
| Melting range | 1290 – 1350 °C |
| Magnetic | Non-magnetic |
| PREN (approx.) | ≈ 51 |
Inconel 625 Equivalent Grades
Inconel 625 flange dimensions — ASME B16.5 Class 150 & 300
Outside dimensions depend only on size and class, not on the alloy, so 625 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 625 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 625 is most often mixed up with Hastelloy C276 — 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 | Inconel 625 | Hastelloy C276 |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | As specified | As specified |
| Titanium | As specified | — |
| Niobium | As specified | — |
| Tungsten | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
Inconel 625 Flanges Price — What Decides It
Two quotes for "625 flanges" can differ by 20% and both be fair. We quote 625 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 625 flanges by type
Inconel 625 Flanges Applications
Inconel 625 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 625 Flanges vs 825, 2507 and C276
| Grade | Flanges standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Inconel 825 | ASTM B564 | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| 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 |
| Hastelloy C276 | ASTM B462 / B564 | ≈ 68 | The most aggressive mixed acids, wet chlorine and hypochlorite |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
Inconel 625 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 625 fits.
About 9% molybdenum gives PREN above 50 — seawater pitting is rarely a concern.
Niobium strengthens the matrix without heat treatment.
High nickel makes it virtually immune to chloride stress-corrosion cracking.
Keeps useful strength and oxidation resistance at high temperature.
How your 625 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 against your order; PMI before processing is available on request.
- 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 625 Flanges
Inconel 625 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiCrMo-3 (AWS A5.14) |
|---|---|
| Over-alloyed filler | ENiCrMo-3 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 625 fittings and 625 flanges for the matching pipe-system parts.
How to Order Inconel 625 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 625 flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiInconel 625 flanges — questions buyers ask
Is Inconel 625 the same as Alloy 625?
Alloy 625, UNS N06625, W.Nr 2.4856 are names used for Inconel 625 (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 flanges is ordered to ASTM B564 whichever name is on the enquiry.
Which standard covers Inconel 625 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 Inconel 625 Class 300 flange take?
It depends on temperature. ASTM B564 is in ASME B16.5 material group 3.8; read the Class 300 column of that group's table at your design temperature.
Which bolts should I use with Inconel 625 flanges?
Usually B7 (coated), B8M or nickel-alloy studs in Inconel 625 (bar to ASTM B446, where applicable), as the project specifies. In corrosive or sour service the bolting material is set by the project specification.
Can a Inconel 625 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 Inconel 625 flanges be supplied to NACE MR0175?
Inconel 625 is covered by NACE MR0175 / ISO 15156-3 within the environmental limits, heat-treatment conditions and hardness limits that standard sets for it. State the requirement on the order so that condition and hardness are verified and reported on the certificate.
Inconel 625 or Hastelloy C276 — which should I choose?
Inconel 625 is chosen for seawater, high strength and high temperature in one alloy. Hastelloy C276 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