ASTM A182 F91 Flanges are made to ASTM A182 / ASME SA182 F91 Type 1 for supercritical steam service. They are supplied in every common flange type and facing to ASME B16.5, B16.47 and the main EN, DIN, BS and JIS standards.
Raaj Fittings manufactures ASTM A182 F91 flanges in-house at our two plants in India, from ½" to 60" and in Class 150 to Class 2500, 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 standards | ASME B16.5 (½" to 24"), ASME B16.47 Series A and B (26" to 60"), EN 1092-1, DIN, BS 4504, JIS B2220 |
| Pressure class | ASME Class 150, 300, 600, 900, 1500 and 2500; PN 6 to PN 400 |
| Facing | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Male & Female, Tongue & Groove |
| 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 flanges are supplied normalised and tempered (or annealed, as the specification allows) with hardness checked. Welding to chrome-moly pipe requires preheat, controlled interpass temperature and post-weld heat treatment.
Every heat is PMI-verified and its chemistry and mechanical properties are confirmed against the material specification before the flanges 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.
We make ASTM A182 F91 Flanges from ½" to 24" to ASME B16.5 and from 26" to 60" to ASME B16.47 Series A and B, in Class 150 to 2500, and to EN 1092-1, DIN, BS and JIS standards in PN ratings.
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.