Weld Neck Flanges
A high-hub flange butt-welded to the pipe and bored to match the pipe inside diameter. It transfers stress smoothly into the pipe wall — the strongest, most reliable joint for high-pressure, high-temperature and cyclic service.
Technical Data
| Weld Neck Flanges — specification | |
|---|---|
| Size range | ½–60″ NPS |
| Rating | 150–2500 ASME class |
| EN rating | PN 2.5–400 EN 1092-1 |
| Schedule | bore-matched hub |
| Pressure | Class 2500 ≤12" · 1500 to 24" |
| Standards | ASME B16.5 · EN 1092-1 (Type 11) |
| Material | Carbon steel A105, P250GH; stainless |
| Facing | RF / RTJ |
| Bore | Bored to pipe ID / schedule |
| ASTM A105 | Forged carbon steel |
| ASTM A182 | F304/F304L · F316/F316L (stainless) |
| ASTM A350 LF2 | Low-temperature carbon steel |
| EN 1092-1 | P245GH · P265GH · 1.4301 · 1.4404 |
Key points
- High-pressure & high-temperature process
- Cyclic, fatigue & thermal-shock service
- Oil, gas, refinery & petrochemical
- Power generation & steam lines
- Critical & hazardous-fluid piping
Drawing & Dimensions
Dimensioned drawing from the YTM Pipe flange catalogue (Class 150 shown). Dimensions and drilling to ASME B16.5 / B16.47 — complete class tables in the datasheet download.
Click the drawing to enlargeDatasheet & Documents
The official Weld Neck Flanges datasheet — specification, materials, standards and the complete dimension tables.
ISO 9001:2015 certified quality
How to Order
Worked example
WELD NECK · 8″ · Class 600
ASME B16.5 · RF (6.4 mm)
Bore SCH 40 · ASTM A105
MTC EN 10204 3.1Also in This Range
Questions & Answers
What is a weld neck flange?
A weld neck flange has a long tapered hub that is butt-welded to the pipe, transferring stress from the flange into the pipe wall. It is the preferred flange for high-pressure, high-temperature and cyclic service. Dimensions follow ASME B16.5, B16.47 or EN 1092-1 Type 11.
What is the difference between a weld neck and slip-on flange?
A weld neck flange is butt-welded to the pipe through a tapered hub and has a single full-penetration weld, making it the stronger choice for high pressure and fatigue. A slip-on flange slides over the pipe end and is fillet-welded inside and out — cheaper and easier to align, but rated for lower pressures.
What bore should I specify?
The bore is matched to your pipe schedule, so state the pipe schedule or wall thickness with the size and class — for example 8" Class 600 bored for SCH 40.
What size range do you supply for weld neck flanges?
½–60″ NPS. Other sizes can usually be supplied on request — send your requirement for confirmation.
Which standards and grades are available?
ASTM A105: Forged carbon steel · ASTM A182: F304/F304L · F316/F316L (stainless) · ASTM A350 LF2: Low-temperature carbon steel. See the datasheet for the complete list.
What materials are offered?
Carbon steel A105, P250GH; stainless.
Is a technical datasheet available?
Yes — the official YTM Pipe datasheet with dimensions, materials and standards can be downloaded on this page.
How do I get a price?
Send size, specification and quantity through the Request-a-Quote form, WhatsApp or [email protected] — our team responds within one business day.
Weld Neck Flanges. Specified. Checked. Delivered.
Manufactured and supplied to the governing standard, inspected and documented before dispatch.