Lap-joint stub ends designed for use with lap-joint flanges to provide a detachable flange connection while the stub end is welded to the pipe. Suitable for applications requiring frequent dismantling, inspection or replacement of piping components.
A lap-joint stub end is a pipe fitting used with a lap-joint flange to create a flanged connection. The stub end is welded to the pipe, while the loose lap-joint flange is free to rotate around the stub end.
This arrangement allows the flange to be rotated for easier bolt-hole alignment and can simplify assembly, inspection and dismantling of piping joints.
Lap-joint stub ends are particularly useful where piping systems require frequent disassembly, where alignment is important, or where the use of higher-alloy pipe material can be minimized by using a suitable stub-end arrangement.
Used with a matching lap-joint flange to create a detachable flanged piping connection.
A lap-joint connection consists of a welded stub end and a loose lap-joint flange. The two components work together as a complete flanged joint.
The stub end is welded to the pipe and provides the sealing face against the gasket. Its extended end interfaces with the loose lap-joint flange.
The lap-joint flange is a loose flange that fits over the stub end. It can rotate around the stub end, making bolt alignment and assembly easier.
The stub end and matching lap-joint flange are used together with the appropriate gasket and bolting to create the complete flanged connection.
Stub-end material selection depends on the piping material, process media, temperature, corrosion requirements and applicable project specification.
| Material | Typical Specification | Typical Application |
|---|---|---|
| Carbon Steel | ASTM A234 WPB | General Process · Oil & Gas |
| Low-Temperature Carbon Steel | ASTM A420 WPL6 | Low-Temperature Service |
| Alloy Steel | ASTM A234 WP11 / WP22 | High-Temperature Service |
| Stainless Steel | ASTM A403 WP304 / WP316 | Corrosive / Process Service |
Long-pattern stub end dimensions for use with a compatible lap joint backing flange.
Swipe horizontally to view every column.
| NPS | D(mm) | Fstub(mm) | Glap(mm) | r(mm) | tSch 40(mm) |
|---|---|---|---|---|---|
| ½ | 21.34 | 76.20 | 35.00 | 3.00 | 2.77 |
| ¾ | 26.67 | 76.20 | 42.90 | 3.00 | 2.87 |
| 1 | 33.40 | 101.60 | 50.80 | 3.00 | 3.38 |
| 1 ¼ | 42.16 | 101.60 | 63.50 | 4.80 | 3.56 |
| 1 ½ | 48.26 | 101.60 | 73.20 | 6.40 | 3.68 |
| 2 | 60.33 | 152.40 | 91.90 | 7.90 | 3.91 |
| 2 ½ | 73.03 | 152.40 | 104.60 | 7.90 | 5.16 |
| 3 | 88.90 | 152.40 | 127.00 | 9.70 | 5.49 |
| 3 ½ | 101.60 | 152.40 | 139.70 | 9.70 | 5.74 |
| 4 | 114.30 | 152.40 | 157.20 | 11.20 | 6.02 |
| 5 | 141.30 | 203.20 | 185.70 | 11.20 | 6.55 |
| 6 | 168.28 | 203.20 | 215.90 | 12.70 | 7.11 |
| 8 | 219.08 | 203.20 | 269.70 | 12.70 | 8.18 |
The tabulated t is the Schedule 40 reference pattern.
State the required pattern, wall, lap thickness and facing finish; verify compatibility with the lap joint flange bore and radius.
Product requirements can be reviewed against the applicable material specification, dimensional standard and purchase order requirements before supply.
Common questions about stub ends, lap-joint flanges, materials, sizing and applications.
A lap-joint stub end is welded to the pipe and used with a loose lap-joint flange to create a flanged connection. The arrangement allows the flange to rotate for easier bolt-hole alignment and can simplify dismantling.
Yes. A lap-joint stub end is normally used together with a matching lap-joint flange. The flange is loose and rotates around the stub end, while the stub end provides the pipe-side connection and gasket seating interface.
Lap-joint stub ends are generally dimensioned according to applicable ASME B16.9 requirements, while the corresponding lap-joint flange is typically selected according to the applicable flange standard such as ASME B16.5.
Provide the nominal pipe size, schedule or wall thickness, material grade, required stub-end pattern, quantity and applicable standard. If the matching lap-joint flange is also required, include its size, pressure class and material.
Yes. A requirement can include the stub end, matching lap-joint flange, gasket and compatible fasteners. These components can also be included within a mixed piping Bill of Materials.
Share the size, schedule, material, stub-end pattern, flange class, quantity and applicable specification. Mixed piping component requirements are also welcome.
