Inconel 718 Lap Joint FlangeASTM B637 · ASME B16.5 · Manufacturer, stockist & exporter, India
Alloy 718 · UNS N07718 · LJ
An Inconel 718 lap joint flange is a loose flange that sits behind a stub end welded to the pipe, made from Inconel 718 to ASTM B637. A lap joint flange rotates freely, making bolt alignment easy on lines that are dismantled often. In corrosive service the flange never touches the fluid, so it can be carbon steel while the stub end is the alloy — a big saving.
- ASTM B637
- ASME B16.5
- 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 Lap Joint Flange?
- What it is
- A loose flange that sits behind a stub end welded to the pipe
- Material
- ASTM B637
- Dimensions
- ASME B16.5
- Grade
- Inconel 718 · UNS N07718
- Best at
- Very high strength at temperatures up to about 650 °C
Inconel 718 Lap Joint Flange Specification
| Product | Inconel 718 Lap Joint Flange |
|---|---|
| Material standard | ASTM B637 |
| Dimensional standard | ASME B16.5 |
| 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 Lap Joint Flange
A lap joint flange rotates freely, making bolt alignment easy on lines that are dismantled often. In corrosive service the flange never touches the fluid, so it can be carbon steel while the stub end is the alloy — a big saving.
- Used with a stub end (MSS SP-43 or ASME B16.9)
- Flange can be a cheaper material than the stub end
- Lower pressure rating than a weld neck
Inconel 718 Lap Joint 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 Lap Joint 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 Lap Joint Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiInconel 718 Lap Joint 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 Lap Joint Flange — questions buyers ask
Does a lap joint flange have to be the same alloy as the pipe?
No. Only the stub end touches the fluid, so the backing flange is often carbon steel, saving the cost of an alloy forging.
Which standard covers Inconel 718 lap joint flanges?
The material is ASTM B637; dimensions follow ASME B16.5. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a Inconel 718 lap joint 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 lap joint 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