ASTM A182 F91 Forged Fittings are made to ASTM A182 / ASME SA182 F91 Type 1 for supercritical steam service. Socket weld and threaded fittings are dimensioned to ASME B16.11 for small-bore ASTM A182 F91 piping.
Raaj Fittings manufactures ASTM A182 F91 forged fittings in-house at our two plants in India, from ⅛" to 4" in Class 2000 to 9000, and exports them to EPC contractors, fabricators and stockists across the Middle East, Europe and the Americas, with full traceability and EN 10204 certificates.
| Material specification | ASTM A182 / ASME SA182 F91 Type 1 |
|---|---|
| Dimensional standard | ASME B16.11; MSS SP-79, SP-83, SP-95 and SP-97 |
| Size range | ⅛" to 4" NPS |
| Pressure class | Socket weld: Class 3000, 6000, 9000. Threaded: Class 2000, 3000, 6000 |
| Threads | NPT to ASME B1.20.1; BSPT / BSPP to BS 21 / ISO 7-1 |
| Certification | EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request |
ASTM A182 F91 is a modified 9% chromium, 1% molybdenum steel micro-alloyed with vanadium, niobium and nitrogen. Its tempered martensitic structure gives far higher creep strength than conventional chrome-moly steels, allowing thinner walls in supercritical and ultra-supercritical power plant steam piping.
| Element, % | ASTM A182 F91 |
|---|---|
| Carbon (C) | 0.08 – 0.12 |
| Manganese (Mn) | 0.30 – 0.60 |
| Phosphorus (P) | 0.020 max |
| Sulphur (S) | 0.010 max |
| Silicon (Si) | 0.20 – 0.50 |
| Chromium (Cr) | 8.0 – 9.5 |
| Nickel (Ni) | 0.40 max |
| Molybdenum (Mo) | 0.85 – 1.05 |
| Vanadium (V) | 0.18 – 0.25 |
| Niobium (Nb) | 0.06 – 0.10 |
| Nitrogen (N) | 0.03 – 0.07 |
| Property | ASTM A182 F91 |
|---|---|
| Yield strength, min. | 415 MPa (60 ksi) |
| Hardness, max. | 248 HBW |
| UNS | Werkstoff Nr. | EN / DIN | Other |
|---|---|---|---|
| K90901 | 1.4903 | X10CrMoVNb9-1 | P91 / T91 (pipe / tube) |
ASTM A182 F91 socket weld and threaded fittings are forged and heat treated, then machined. Socket welds in chrome-moly need preheat and post-weld heat treatment like any other weld in the system.
| Pipe | Socket weld class | Threaded class |
|---|---|---|
| SCH 80 / XS | 3000 | 2000 |
| SCH 160 | 6000 | 3000 |
| XXS | 9000 | 6000 |
Every heat is PMI-verified and its chemistry and mechanical properties are confirmed against the material specification before the forged fittings are released. Each piece is marked with grade, size, rating and heat number for traceability to its EN 10204 3.1 mill test certificate. EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request, as are PED 2014/68/EU compliance for European projects and IBR certification for Indian boiler applications.
Heat treatment records and hardness results are reported for each heat.
Its creep strength at 550–600 °C is far higher than F22, so steam piping can be thinner and lighter, which reduces cost and thermal fatigue in modern high-efficiency plants.
Class 3000 socket weld fittings match SCH 80 pipe, Class 6000 matches SCH 160 and Class 9000 matches XXS. For threaded fittings, the matching classes are 2000, 3000 and 6000.
Every order is supplied with EN 10204 3.1 mill test certificates showing heat chemistry and mechanical properties to ASTM A182 F91 Type 1. EN 10204 3.2 certification and inspection by your nominated third-party agency are available on request.