Pipe Fittings · ASME B16.9 · MSS SP-43
Stub End — ASME B16.9
Stub end — a short pipe length with a flared lap that works with a lap joint flange. Stub ends are welded to the pipe and backed by a loose lap joint flange. Type A (long pattern, ASME B16.9) and short-pattern MSS SP-43 stub ends are the common choices.
- ASME B16.9
- 22 grades
- EN 10204 3.1 / 3.2
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
Stub End: What to Know Before Ordering
- Long pattern (ASME B16.9) and short pattern (MSS SP-43)
- Type A, B and C lap designs
- Used with a carbon-steel backing flange to save alloy
Stub End Materials & Grades
| Grade | Material standard | Best for |
|---|---|---|
| Inconel 825 stub end | ASTM B366 WPNICMC | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| SS 904L stub end | ASTM A403 WP904L | Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water |
| SS 304 stub end | ASTM A403 WP304 | General corrosion resistance, food, water and architectural work |
| SS 304L stub end | ASTM A403 WP304L | Welded tanks, piping and vessels in general corrosive service |
| SS 310 / 310S stub end | ASTM A403 WP310S | Furnaces, burners and heat treatment at high temperature |
| SS 316 / 316L stub end | ASTM A403 WP316L | Chloride-bearing process fluids, marine air and pharmaceutical service |
| SS 321 stub end | ASTM A403 WP321 | High-temperature service between 425 and 815 °C |
| SS 347 stub end | ASTM A403 WP347 | Welded high-temperature piping in refineries and power plants |
| Duplex 2205 stub end | ASTM A815 WPS31803 / WPS32205 | Strength with chloride resistance at a stainless-steel budget |
| Super Duplex 2507 stub end | ASTM A815 WPS32750 | Seawater and high-chloride service where strength also matters |
| Inconel 600 stub end | ASTM B366 WPNCI | High-temperature oxidation, caustic and nuclear service |
| Inconel 625 stub end | ASTM B366 WPNCMC | Seawater, high strength and high temperature in one alloy |
| Inconel 718 stub end | Machined from B637 on request | Very high strength at temperatures up to about 650 °C |
| Incoloy 800 / 800H / 800HT stub end | ASTM B366 WPNIC | Furnaces, petrochemical heaters and high-temperature piping |
| Hastelloy C276 stub end | ASTM B366 WPHC276 | The most aggressive mixed acids, wet chlorine and hypochlorite |
| Hastelloy C22 stub end | ASTM B366 WPHC22 | Mixed oxidising and reducing acids, and weld overlays |
| Monel 400 stub end | ASTM B366 WPNC | Seawater, hydrofluoric acid and marine service |
| Super Duplex S32760 stub end | ASTM A815 WPS32760 | Seawater firewater, injection and offshore piping |
| ASTM A106 Gr B stub end | ASTM A234 WPB | High-temperature process and steam piping in refineries and power plants |
| ASTM A333 Gr 6 stub end | ASTM A420 WPL6 | Cold-climate and refrigerated piping down to −45 °C |
| ASTM A335 P11 stub end | ASTM A234 WP11 | Steam and hot-oil piping up to about 550 °C |
| ASTM A335 P22 stub end | ASTM A234 WP22 | High-pressure steam and hydrogen service up to about 580 °C |
Other pipe fittings
ElbowA fitting that changes the direction of a pipe run.TeeA fitting with a 90° branch that splits or combines flow.ReducerA fitting that joins two pipes of different sizes.CapA fitting that closes the end of a pipe.CrossA four-way fitting with branches at 90°.BendA pipe bend with a larger radius than a standard elbow.LateralA fitting with a 45° branch.CouplingA short forged fitting that joins two pipes.UnionA three-piece forged fitting that joins pipes and can be taken apart.NippleA short length of pipe, threaded or plain, used to connect fittings.PlugA threaded fitting that closes a female connection.
Stub end — questions buyers ask
Long or short stub end?
Long-pattern stub ends to ASME B16.9 suit most piping; short-pattern MSS SP-43 stub ends save alloy and space in low-pressure lines.
Which grades are stub ends available in?
Inconel 825, SS 904L, SS 304, SS 304L, SS 310 / 310S, SS 316 / 316L, SS 321, SS 347, Duplex 2205, Super Duplex 2507, Inconel 600, Inconel 625, Inconel 718, Incoloy 800 / 800H / 800HT, Hastelloy C276, Hastelloy C22, Monel 400, Super Duplex S32760, ASTM A106 Gr B, ASTM A333 Gr 6, ASTM A335 P11, ASTM A335 P22.
Which standard covers stub end dimensions?
ASME B16.9 · MSS SP-43. The material standard depends on the grade.
India · Gulf · South-East Asia · South America · Europe · USA · UKSend your stub end requirement today.
Start RFQ