What Is ASME B16.9?
ASME B16.9 is the American National Standard for factory-made wrought buttwelding fittings from NPS 1/2 through NPS 48. It covers 90-degree and 45-degree elbows, 180-degree returns, tees, reducers, caps, stub ends and crosses, with dimensional requirements, tolerances, marking, and material specifications (ASTM A234, A403, A420).
Fitting Types Covered
- 90° / 45° Elbows — long radius and short radius, NPS 1/2–48
- 180° Returns — long and short radius
- Tees — equal and reducing, NPS 1/2–48
- Reducers — concentric and eccentric
- Caps — all schedules
- Stub Ends — lap joint type A/B/C (per MSS SP-43)
- Crosses — equal and reducing
Wall Thickness (Schedule)
Fittings are available in standard schedules: 5S, 10S, 40S, 80S (stainless), STD, XS, XXS, and Schedule 10 through Schedule 160, matching the pipe wall they are welded to.
Common Materials (ASTM / ASME)
| Material Standard | Grade | Typical Service |
|---|---|---|
| A234 | WPB / WPC | Carbon steel, -29°C to 425°C |
| A403 | WP304 / WP304L / WP316 / WP316L | Stainless steel, up to 538°C |
| A420 | WPL6 | Low-temperature carbon steel |
Related Standards
- ASME B16.5 — Pipe Flanges (NPS 1/2–24)
- ASME B16.11 — Socket-Welding & Threaded Fittings
- Our Fittings Range
FAQ
What sizes does ASME B16.9 cover?
Factory-made buttwelding fittings from NPS 1/2 through NPS 48, with some types available to NPS 60 by agreement.
What schedules are available?
5S, 10S, 40S, 80S, STD, XS, XXS, and Schedule 10 to 160, matching ASME B36.10 / B36.19 pipe wall thicknesses.
Can ASME B16.9 fittings be used with B16.5 flanges?
Yes — B16.9 fittings are designed to match the pipe schedule and bore of flanges covered by ASME B16.5 for a complete welded system.
Need This Standard for Your Project?
We manufacture and export flanges, fittings and gaskets to ASME standards. Send your standard, size, material, and quantity — we reply within 24 hours.