Buttweld and socketweld elbows, tees, reducers, caps, crosses to ASTM A815 / ASME B16.9 / B16.11
A piping system in seawater, sour gas, or brine service is only as corrosion-resistant as its weakest fitting. Where the straight-pipe runs are super duplex (per ASTM A790) the elbows, tees, reducers, and end-caps must match: a 22Cr standard duplex elbow on a super duplex line creates a galvanic boundary that fails first. ASTM A815 (Standard Specification for Wrought Ferritic, Ferritic / Austenitic, and Martensitic Stainless Steel Piping Fittings) covers Ferralium 255 (UNS S32550) wrought fittings to ASME B16.9 buttweld and ASME B16.11 socketweld dimensional. Per-heat EN 10204 type 3.2 MTC, ferrite content within 35 to 55%, hardness ≤ 32 HRC for NACE MR0175. RFQ: info@torqbolt.com / WhatsApp +91-22-66157017.
| Fitting | Standard | Size envelope | End preparation |
|---|---|---|---|
| Long-radius elbow 90° / 45° | ASME B16.9 | 1/2" to 24" NPS | Buttweld bevel per ASME B16.25 |
| Short-radius elbow 90° | ASME B16.9 | 1/2" to 24" NPS | Buttweld bevel |
| Equal tee, reducing tee | ASME B16.9 | 1/2" to 24" NPS | Buttweld bevel |
| Concentric / eccentric reducer | ASME B16.9 | 1/2" × 3/8" to 24" × 22" | Buttweld bevel |
| End cap | ASME B16.9 | 1/2" to 24" | Buttweld bevel |
| Socketweld 90° / 45° elbow, tee, coupling, half-coupling, cap | ASME B16.11 class 3000 / 6000 | 1/8" to 4" NPS | Socketweld pocket |
| Threaded NPT fittings | ASME B16.11 | 1/8" to 4" NPS | NPT thread per ASME B1.20.1 |
ASME B16.9 buttweld fittings are produced by hot-forming from seamless pipe, plate, or seamless tube, then solution-annealed at 1080 °C and water-quenched to restore the wrought ferrite-austenite microstructure. Hot-forming is performed in the 1050 to 1200 °C austenitisation range with finish-form temperature held above 950 °C to avoid sigma-phase precipitation in the inter-pass window. Socketweld and threaded fittings to ASME B16.11 are typically forged from forged bar or machined from solid bar with the socket recess and thread cut as final operations. All fittings ship with EN 10204 type 3.2 MTC documenting the heat-treat record, hardness traverse, ferrite-content point count, and NACE MR0175 conformance with ISO 15156-3 Table A.10 reference.
