Ferralium 255 seamless pipe (UNS S32550 / EN 1.4507) is supplied per ASTM A790 (Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe). Solution-annealed at 1100 °C with water quench. Per-heat MTC (EN 10204 type 3.2) documents chemistry, mechanical properties, ferrite content per ASTM E562, hydrostatic test result, and PREN calculation. Same ASTM A790 spec also covers Duplex 2205 pipe (UNS S31803/S32205), Super Duplex 2507 (S32750), and Zeron 100 (S32760), Ferralium 255 sits in the super-duplex tier (PREN ≥ 40) above standard duplex 2205 (PREN ~35).
| NPS | OD | Common schedules | Wall thickness range |
|---|---|---|---|
| 1/2" | 21.3 mm | SCH 10S / 40S / 80S / 160 / XXS | 2.11–7.47 mm |
| 1" | 33.4 mm | SCH 10S / 40S / 80S / 160 / XXS | 2.77–9.09 mm |
| 2" | 60.3 mm | SCH 10S / 40S / 80S / 160 / XXS | 2.77–11.07 mm |
| 4" | 114.3 mm | SCH 10S / 40S / 80S / 120 / 160 / XXS | 3.05–17.12 mm |
| 6" | 168.3 mm | SCH 10S / 40S / 80S / 120 / 160 / XXS | 3.40–21.95 mm |
| 8" | 219.1 mm | SCH 10S / 40S / 80S / 120 / 160 / XXS | 3.76–22.23 mm |
| 12" | 323.9 mm | SCH 10S / 40S / 80S / 120 / 160 | 4.57–33.32 mm |
| 24" | 609.6 mm | SCH 10S / 40S / 80S | 6.35–24.61 mm |
ASTM A790 covers both seamless (manufactured by extrusion / pilger / cold-pilger) and welded (manufactured by autogenous TIG, plasma, or with filler addition). Welded pipe must meet additional weld-zone ferrite balance requirements (35–65% per NORSOK M-630) and heat-input control (typically 0.5–2.5 kJ/mm). For NORSOK M-650 qualified seamless pipe, the QTR documents pilger pass-schedule and final solution-anneal cycle. For sour-service applications (NACE MR0175), seamless is generally preferred to eliminate weld-zone variability.
For seawater service above 30 °C, sour-gas service exceeding standard-duplex NACE MR0175 limits, or service involving reducing acids, upgrade from Duplex 2205 pipe (UNS S31803, PREN ~35) to Ferralium 255 pipe (UNS S32550, PREN ≥ 40) is justified. See Ferralium 255 vs Duplex 2205 upgrade guide for full selection criteria. Both grades supplied to identical ASTM A790 spec; super-duplex pipe simply has higher chemistry / PREN / CPT margin.
Per-heat EN 10204 type 3.2 MTC with chemistry, mechanical properties, ferrite content, PREN calculation, hydrostatic test certificate. NORSOK M-650 QTR available on request per material data sheet MDS D55. NACE MR0175 / ISO 15156-3 sour-service compliance certified per heat. Contact info@torqbolt.com or +91-22-66157017 for quotation, lead time, and project-specific spec compliance.
