Inconel 718 Long Weld Neck FlangeASTM B637 · ASME B16.5 (flange end) · Manufacturer, stockist & exporter, India
Alloy 718 · UNS N07718 · LWN
An Inconel 718 long weld neck flange is a weld neck flange with an extended straight neck, used as a vessel nozzle, made from Inconel 718 to ASTM B637. Long weld neck flanges are used as nozzles on vessels and columns, with the neck welded into the shell. Standard neck lengths are 9" and 12", or made to drawing.
- ASTM B637
- ASME B16.5 (flange end)
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an Inconel 718 Long Weld Neck Flange?
- What it is
- A weld neck flange with an extended straight neck, used as a vessel nozzle
- Material
- ASTM B637
- Dimensions
- ASME B16.5 (flange end)
- Grade
- Inconel 718 · UNS N07718
- Best at
- Very high strength at temperatures up to about 650 °C
Inconel 718 Long Weld Neck Flange Specification
| Product | Inconel 718 Long Weld Neck Flange |
|---|---|
| Material standard | ASTM B637 |
| Dimensional standard | ASME B16.5 (flange end) |
| Sizes | ½" – 24" (ASME B16.5) · 26" – 60" (ASME B16.47) |
| Pressure class | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | RF · FF · RTJ · tongue & groove |
| Bore | To match pipe schedule (state on order) |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Long Weld Neck Flange
Long weld neck flanges are used as nozzles on vessels and columns, with the neck welded into the shell. Standard neck lengths are 9" and 12", or made to drawing.
- Heavy-barrel and equal-barrel designs
- Neck length 9" / 12" or to drawing
- Often machined from solid bar in alloys
More on choosing: Long weld neck flange guide.
Inconel 718 Long Weld Neck Flange: Why 718 for long weld neck flanges
Long weld neck flanges are used as nozzles on vessels and columns, with the neck welded into the shell. Standard neck lengths are 9" and 12", or made to drawing. In Inconel 718, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Nickel-alloy flanges are used where acids, chlorides or heat defeat stainless. Inconel 718 is picked for very high strength at temperatures up to about 650 °C. |
|---|---|
| Typical service | Oil & gas — Wellhead parts, hangers and high-strength bolting. |
| Bolting | B7 (coated), B8M or nickel-alloy studs such as Inconel 718 from ASTM B637, as the project specifies |
| Welding to carbon steel | A nickel-base filler such as ERNiCr-3 (or ERNiCrMo-3) is used when joining it to carbon steel |
| Matching filler | ERNiFeCr-2 (AWS A5.14) |
| Sour service | Listed in NACE MR0175 / ISO 15156-3 within its limits — state it on the order |
Inconel 718 Long Weld Neck Flange 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 Long Weld Neck Flange Mechanical Properties
| Solution-treated and aged | Value |
|---|---|
| Tensile strength | 1275 MPa · 185 ksi |
| Yield strength 0.2% | 1034 MPa · 150 ksi |
| Elongation | 12% |
Full chemistry, properties and equivalents are on the Inconel 718 grade page.
Other Inconel 718 flanges
Inconel 718 Long Weld Neck Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiInconel 718 Long Weld Neck Flange dimensions — ASME B16.5 Class 150 & 300
Outside diameter, thickness and bolting are set by 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.
Inconel 718 Long Weld Neck Flange — questions buyers ask
What is the difference between equal-barrel and heavy-barrel LWN?
Equal-barrel has a uniform neck; heavy-barrel has a thicker neck for extra reinforcement at the vessel wall.
Can Inconel 718 long weld neck flanges be welded to carbon steel?
Yes — a nickel-base filler such as ERNiCr-3 (or ERNiCrMo-3) is used when joining it to carbon steel.
Which standard covers Inconel 718 long weld neck flanges?
The material is ASTM B637; dimensions follow ASME B16.5 (flange end). Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a Inconel 718 long weld neck flange?
The alloy price, the size and pressure class, quantity, and the testing and documents required. Send your list and we quote the same working day.
Can you supply Inconel 718 long weld neck flanges to NACE MR0175?
Yes. Inconel 718 is listed in NACE MR0175 / ISO 15156-3 within its limits; state NACE compliance on the order and it is confirmed on the certificate.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026