Stub End - Butt-Weld Pipe Fitting
A butt-weld stub end is designed to be used with a loose lap joint flange. The short welded stub carries the seal while the free-spinning flange allows the joint to be dismantled quickly for inspection and cleaning without cutting the line. Manufactured to BS EN 10253-2 and ASME B16.9, the stub end lap face is machined to provide a reliable sealing surface against the backing flange.
Each stub end is bevelled to ASME B16.25 for full-penetration butt welding. Fittings are supplied with heat numbers and material test certificates for complete traceability throughout the supply chain.
Standards & Materials
Manufactured in accordance with BS EN 10253-2 and ASME B16.9 in carbon and stainless steel grades suitable for UK process and hygienic pipework.
| Attribute | Specification |
|---|---|
| Manufacturing Standard | BS EN 10253-2 / ASME B16.9 |
| Carbon Steel | ASTM A234 WPB |
| Stainless Steel | ASTM A403 WP304/304L/316/316L |
| Special Grades | Duplex & Super Duplex (UNS S31803 / S32205 / S32750), Alloy 20, Inconel 625 / 825, Monel 400, Hastelloy C-276 - available on request |
| Fabrication | Seamless or welded |
| Test Pressure | Up to 1500 psi |
| Lap Face | Machined to ASME B16.5 raised-face dimensions |
Dimensions & Sizes
Available from 1/2" (DN15) to 24" (DN600) in schedules 10, 40 and 80. The table below gives the lap face outer diameter (G), face length (F) and Schedule 40 wall thickness for representative sizes, to ASME B16.9.
| Nominal Size | DN | Lap Face OD G (mm) | Face Length F (mm) | SCH 40 Wall (mm) |
|---|---|---|---|---|
| 1" | 25 | 35 | 51 | 3.38 |
| 2" | 50 | 64 | 64 | 3.91 |
| 3" | 80 | 89 | 64 | 5.49 |
| 4" | 100 | 114 | 64 | 6.02 |
| 6" | 150 | 168 | 76 | 7.11 |
| 8" | 200 | 219 | 76 | 8.18 |
Performance & Benefits
Stub ends with lap joint flanges allow rapid dismantling of pipework without the need to rotate or twist the pipe. The free-spinning backing flange simplifies bolt-hole alignment and speeds up joint assembly. This combination is particularly cost-effective where exotic alloy pipe is used, as only the stub end need be made from the higher-grade material while the backing flange can be carbon steel.
Typical Applications
Widely used in hygienic and process lines throughout the UK where frequent dismantling is needed, such as food, beverage, pharmaceutical and chemical plants. Also specified in heat exchanger nozzle connections, sampling points, inspection openings and any application requiring repeated joint break-out.
Quality Assurance & Traceability
Every fitting is manufactured to BS EN 10253-2 and ASME B16.9 and supplied with full material traceability and EN 10204 Type 3.1 test certificates. Heat numbers are recorded throughout production to support inspection, QA and UK project-compliance requirements.
Supply & Delivery
Stocked at our Sheffield, UK facility and delivered nationwide across England, Scotland and Wales. We offer fast dispatch from stock with tracked UK delivery to site, and next-day options for common sizes.
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Which sizes and schedules are available?
Available from ½" (DN15) to 24" (DN600) in schedule 10, 40 and 80, in both metric and imperial sizes to suit UK installations.
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Can you provide material certificates?
Yes. Material test certificates and full traceability documentation are available with every order, to project and quality-management requirements.
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Do you supply the backing flange with the stub end?
Stub ends are supplied as fittings on their own. Lap joint backing flanges are available separately and can be quoted alongside the stub end to give you a complete joint package. Contact us with your size and pressure class for a combined quotation.
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Do you deliver across the UK?
We deliver nationwide throughout England, Scotland and Wales, with fast dispatch from stock and tracked deliveries to site.