Alloy steel F91 flange manufacturer, Mumbai. UNS K91560 9Cr-1Mo-V creep-resistant steel for ultra-supercritical power steam lines to 650°C. Quote in 30 min.
ASTM A182 F91 is a 9% Chromium, 1% Molybdenum alloy steel micro-alloyed with Vanadium and Niobium, providing exceptional creep rupture strength and thermal fatigue resistance at operating temperatures up to 650°C.
Governing specification limits per ASTM / ASME standards. Actual values provided on EN 10204 3.1 MTC.
| Element | Specification Limit / Composition |
|---|---|
| Chromium (Cr) | 8.0 - 9.5% |
| Molybdenum (Mo) | 0.85 - 1.05% |
| Vanadium (V) | 0.18 - 0.25% |
| Niobium (Nb) | 0.06 - 0.10% |
| Nitrogen (N) | 0.030 - 0.070% |
| Property | Specification Limit |
|---|---|
| Yield Strength | 415 MPa (60 ksi) min |
| Tensile Strength | 585 - 760 MPa |
| Service Temp Range | Up to 650°C (1,200°F) |
| Service Temp | Class 150 | Class 300 | Class 600 | Class 900 |
|---|---|---|---|---|
| Ambient (-29 to 38°C) | 290 psi | 750 psi | 1500 psi | 2250 psi |
Flanges in Alloy Steel F91 Flanges are manufactured via precision closed-die or open-die forging to establish continuous metallurgical grain flow along the flange hub and neck contour. Raw billets are heated in calibrated gas-fired furnaces under strictly controlled soak temperatures to eliminate microstructural defects.
Depending on the alloy grade, components undergo certified thermal conditioning: normalizing for carbon steels (A105N, A350 LF2), rapid water quench solution annealing at 1040°C–1120°C for stainless and duplex grades, or controlled aging for nickel superalloys. This ensures exceptional notch toughness, yield strength, and resistance to stress corrosion cracking.
Final machining is executed on heavy-duty CNC turning centers to guarantee precise raised face, flat face, or ring type joint (RTJ) dimensions compliant with ASME B16.5, ASME B16.47, DIN, or EN 1092-1 standards. Gasket contact surfaces receive spiral or concentric serrations strictly controlled between 125 and 250 µin Ra.
Every production heat is issued with an EN 10204 Type 3.1 inspection certificate containing full heat chemistry, mechanical tensile test data, and Charpy impact values. Independent Third-Party Inspection (TPI) by Lloyd's, BV, DNV-GL, TÜV, and SGS is readily accommodated for global EPC and refinery contracts.
A: F91 forms a fully martensitic structure upon cooling. Strict PWHT (typically 730°C to 760°C) is mandatory to temper the martensite and restore impact toughness.
Written commercial offer with Mill Test Certificate guarantee.