Weld Neck Flanges by Standard or Drawing
A weld neck flange carries a long tapered hub that is butt-welded to the pipe, so the wall thickness steps down gradually instead of stopping at a fillet. That transition is why it is the type specified for cyclic, high-temperature and high-pressure lines. We forge them from NPS 1/2 to NPS 60 to ASME B16.5 and B16.47, EN 1092-1 Type 11, GOST or your drawing, with an EN 10204 3.1 certificate per heat.
Also called: WN flange, high neck flange, W neck flange.
- NPS 1/2–60
- ASME B16.5 Class 150–2500 · B16.47 Class 75–900
- A105 · LF2 · LF6 · 304/316 · duplex
- MTC 3.1 per heat · PMI and NDT as specified
Weld Neck Flanges Technical Specification
| Standards and sizes | ASME B16.5: Class 150–1500 at NPS 1/2–24 and Class 2500 at NPS 1/2–12. ASME B16.47 Series A and B: NPS 26–60, Class 75–900. EN 1092-1 Type 11, GOST 33259 or your drawing. |
|---|---|
| Facing | RF, RTJ or FF, as the standard or your drawing specifies. |
| Grades |
|
| Documents | EN 10204 3.1 certificate per heat; 3.2 with a third-party inspector on request (example); PMI on alloy grades; UT, MT or PT and third-party witness where the specification requires them. |
| Volume and order size | About 3,000 t of forgings a month across all grades; orders from 1 piece. |
| Typical service | Cyclic, high-temperature and high-pressure lines in oil and gas, petrochemical, power and refinery piping. |
Your standard, drawing revision and project specification govern.
FAQ
Which dimensions must agree with the mating pipe?
Bore or pipe schedule, hub diameter at the weld end, hub length, weld bevel, facing and bolt pattern. We check them against your pipe data before the part is cut.
Do you make low-temperature weld neck flanges in A350 LF6?
Yes, as well as LF2 and LF3. In August 2026 we made a lot of 750 two-inch Class 600 RF weld neck flanges in A350 LF6 Class 2 to ASME B16.5-2025.
Do you forge ASME B16.47 large-diameter weld neck flanges?
Yes. We supply ASME B16.47 Series A and Series B flanges across NPS 26 to NPS 60, in the classes and sizes the standard tabulates for each series. Our D51 mill rolls rings up to 1,500 mm OD and 240 mm thick; larger rings are forged by partner forges near our plant in Dingxiang. Dimensions: ASME B16.47 Flange Dimensions
Commercial terms
Orders from 1 piece · Free samples, you pay the freight · 30% deposit, balance when the goods reach the Chinese port you name · FOB, CFR or CIF
All commercial terms
- Reply time
- We reply to every RFQ within 8 hours.
- Service hours
- 08:00–20:00 Eastern Time (ET; UTC−5, UTC−4 in summer), every day, including public holidays.
- Minimum order
- 1 piece
- Samples
- Free of charge; you pay the freight.
- Lead time
- 9 to 30 days after drawing approval.
- Payment
- 30% deposit with the order; the balance is paid in full when the goods arrive at the port in China that you designate. The same applies to FOB, CFR and CIF.
- Packing
- Surfaces are coated with anti-rust oil. Most orders go in wooden cases, and every wooden case is fumigated. Large parts are steel-strapped onto pallets and wrapped in waterproof tarpaulin.
- Quality claims
- After you report a problem, we give you a handling plan within 8 hours.
- Delivery terms
- Standard: FOB the Chinese port you designate, Incoterms® 2020; we usually ship from Tianjin. On request: CFR or CIF to your destination port, quoted per RFQ. Other Incoterms® 2020 terms, except EXW and DDP, are quoted on request.
Send your RFQ or drawing directly to BLD Forge Direct.
Send your MR, datasheet or drawing as it is. We reply within 8 hours.