Tesco Steel & Engineering manufactures ASTM A182 F9 alloy steel flanges — the 9% chromium, 1% molybdenum (9Cr-1Mo) chrome-moly forging grade. Its high chromium gives the best high-temperature oxidation and sulphidic-corrosion resistance of the standard chrome-moly grades, while molybdenum provides creep strength — making F9 the choice for the hottest refinery and power-plant service. As an air-hardening alloy steel it requires careful preheat and post-weld heat treatment. Available in weld neck, slip-on, blind, socket-weld, threaded, lap-joint, spectacle and orifice types to ASTM A182 / ASME B16.5. Class 150 to 2500, NPS 1/2″ to 24″, PN6 to PN400. ISO 9001:2015 certified. Made in India.
ASTM A182 F9 (9Cr-1Mo) Alloy Steel Flanges
A182 F9 Weld Neck & Blind Flanges
Tesco Steel & Engineering manufactures A182 F9 flanges in all types from weld neck to orifice, Class 150 to 2500 — supplied normalized-and-tempered with EN 10204 3.1 / 3.2 certification, hardness results and third-party inspection on request. Explore the wider alloy steel flange range, the lower-chrome A182 F5 flanges and A182 F22 flanges, the vanadium-modified A182 F91 flanges, and the flange dimension charts.
| ASTM A182 F9 flanges are available in the following specifications: | |
|---|---|
| Material Grade | ASTM A182 / A182M Grade F9 (9Cr-1Mo chromium-molybdenum alloy steel) |
| Alloy Type | Chromium-molybdenum (chrome-moly) air-hardening alloy steel |
| Heat Condition | Annealed or normalized and tempered |
| Size | 1/2″ NB to 24″ NB (DN 15 to DN 600); larger to ASME B16.47 |
| Class / Rating | 150#, 300#, 600#, 900#, 1500#, 2500# · 3000#, 6000#, 9000# (socket-weld / threaded) |
| Pressure Ratings | PN 6 – PN 400 (PN6, 10, 16, 25, 40, 64, 100, 160, 250, 320, 400) |
| Related Specs | Pipe ASTM A335 P9; casting ASTM A217 C12; fittings ASTM A234 WP9; plate A387 Gr9 |
| Dimensional Standards | ASME B16.5, ASME B16.47 (Series A & B), MSS SP-44, DIN EN 1092-1 |
| Flange Types | Weld Neck (WNRF), Slip-On (SORF), Blind, Socket Weld (SWRF), Lap Joint, Threaded / Screwed, Spectacle Blind, Long Weld Neck, Orifice, Plate |
| Flange Faces | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Weld Filler | E505 / ER505 (matching 9Cr-1Mo), with preheat & mandatory PWHT |
| Testing | Hardness, hydrostatic, UT, MT/PT per spec; EN 10204 3.1 / 3.2 |
F9 is the 9Cr-1Mo member of the A182 chrome-moly family. The ~9% chromium — the highest of the standard chrome-moly grades — drives its high-temperature oxidation and sulphidic-corrosion resistance, while ~1% molybdenum gives creep strength.
| Element | ASTM A182 F9 |
|---|---|
| Carbon (C) | 0.15% max |
| Manganese (Mn) | 0.30 – 0.60% |
| Silicon (Si) | 0.50 – 1.00% |
| Chromium (Cr) | 8.0 – 10.0% |
| Molybdenum (Mo) | 0.90 – 1.10% |
| Phosphorus (P) | 0.030% max |
| Sulphur (S) | 0.030% max |
| Mechanical Property | ASTM A182 F9 |
|---|---|
| Tensile Strength (min) | 85 ksi (585 MPa) |
| Yield Strength (min) | 55 ksi (380 MPa) |
| Elongation (min) | ~20% |
| Hardness | ≤ 217 HBW (typical) |
| Service Temperature | Sustained high temperature, ~650°C |
| Condition | Annealed or normalized & tempered |
| Product Form | 9Cr-1Mo Designation |
|---|---|
| Forgings / Flanges | ASTM A182 F9 |
| Seamless Pipe | ASTM A335 P9 |
| Castings | ASTM A217 C12 |
| Fittings | ASTM A234 WP9 |
| Plate | ASTM A387 Gr 9 |
| Common name | 9Cr-1Mo Chrome-Moly Alloy Steel |
F9 Weld Neck Flange (WNRF)
F9 Slip-On Flange (SORF)
F9 Blind Flange
| Flange Type | Description & F9-Specific Use |
|---|---|
| Weld Neck (WNRF) | Tapered hub butt-welded to pipe for high-integrity, hottest refinery piping; weld with E505 filler, preheat & mandatory PWHT. |
| Slip-On (SORF) | Fillet-welded over the pipe; used in chrome-moly piping at moderate pressure. |
| Blind | Seals pipe ends and vessel nozzles in high-temperature hydrocarbon and steam systems. |
| Socket Weld (SWRF) | Small-bore (1/2″–2″) instrument and branch connections in hot service. |
| Lap Joint (LJRF) | Used with an F9 stub end where frequent dismantling is required. |
| Threaded (TRFF) | Internal NPT/BSP threads for non-welded connections. |
| Spectacle Blind / Long Weld Neck | Isolation spades and nozzle/long-neck flanges in A182 F9 for high-temperature duty. |
| Property | F9 | F91 | F5 | F22 |
|---|---|---|---|---|
| Nominal type | 9Cr-1Mo | 9Cr-1Mo-V | 5Cr-0.5Mo | 2.25Cr-1Mo |
| Chromium | ~9% | ~9% | ~5% | ~2.25% |
| Creep strength | High | Highest (V+Nb+N) | High | High |
| Oxidation / sulphidic resistance | Highest of standard grades | Highest | High | Good |
| Typical role | Hottest standard chrome-moly service | Max creep, modern power/refinery | Hot refinery sulphur service | Hydrogen / high-temp |
9% chromium gives the best high-temperature sulphur-corrosion and oxidation resistance of the standard chrome-moly grades.
Molybdenum gives strong creep resistance for sustained hot service to ~650°C.
High-chrome chemistry resists high-temperature hydrogen attack per the Nelson curves.
Long-established refinery and power material with matching pipe (A335 P9), fittings and castings.
| Industry | Typical Application |
|---|---|
| Oil Refining | Fired heaters, crude/vacuum and hydroprocessing hot-section flanges |
| Power Generation | High-temperature boiler, superheater and steam-line flanges |
| Petrochemical | Hottest hydrocarbon process flanged connections |
| Hydrogen / Hydroprocessing | High-temperature hydrogen-service flanges per API 941 |
| Heaters & Furnaces | Fired-heater tube and transfer-line flanged connections |
| Catalytic Units | Hot reactor and regenerator piping flanges |
Made from certified 9Cr-1Mo with PMI verification of chromium and molybdenum — full chemistry and heat-treatment on the MTC.
Supplied normalized-and-tempered (or annealed), with hardness within spec for weldability and service.
WNRF, SORF, blind, socket-weld, threaded, lap-joint, spectacle, LWN, orifice and plate — in RF, FF, RTJ and T&G.
EN 10204 3.1 / 3.2 MTC with hardness results, heat/lot traceability, hydrostatic and third-party inspection on request.
A182 F9 flange prices reflect the 9% chromium alloy content plus forging and controlled heat treatment — it is a premium chrome-moly grade for the hottest refinery and power service. Tesco Steel & Engineering offers competitive ex-works pricing from Mumbai with full export documentation and material traceability. Click Ask for Quote or message us on WhatsApp at +91 92233 66922 with flange type, size (NB), pressure class, quantity and documentation requirements.
Q1. What is an ASTM A182 F9 flange?
An ASTM A182 F9 flange is a forged chromium-molybdenum (chrome-moly) alloy steel flange with about 9% chromium and 1% molybdenum (9Cr-1Mo). The high chromium gives the best high-temperature oxidation and sulphidic-corrosion resistance of the standard chrome-moly grades, while the molybdenum provides creep strength, making F9 suited to the hottest refinery and power-plant service. Flanges are made to ASTM A182 and machined to ASME B16.5 / B16.47 dimensions.
Q2. What is the chemical composition of ASTM A182 F9?
ASTM A182 F9 nominal composition: carbon 0.15% max, manganese 0.30–0.60%, silicon 0.50–1.00%, chromium 8.0–10.0%, molybdenum 0.90–1.10%, phosphorus 0.030% max, sulphur 0.030% max. The ~9% chromium with ~1% molybdenum is the defining 9Cr-1Mo chrome-moly composition.
Q3. What is the difference between A182 F9 and F91?
Both are 9% chromium chrome-moly steels. F9 is the classic 9Cr-1Mo grade. F91 (9Cr-1Mo-V) adds vanadium, niobium and controlled nitrogen, giving substantially higher creep-rupture strength at elevated temperature, so F91 is used for the most demanding high-temperature power and refinery service while F9 remains a workhorse for high-temperature corrosion resistance where F91's extra creep strength is not required.
Q4. What is the difference between A182 F5, F9, F11 and F22?
These are chrome-moly alloy steels with increasing chromium for higher temperature and sulphidic-corrosion resistance: F11 is 1.25Cr-0.5Mo, F22 is 2.25Cr-1Mo, F5 is 5Cr-0.5Mo, and F9 is 9Cr-1Mo. F9's 9% chromium gives the highest high-temperature oxidation and sulphur-corrosion resistance of this standard group, above F5, F22 and F11. Grade selection follows the service temperature and corrosivity.
Q5. Do A182 F9 flanges need post-weld heat treatment?
Yes. F9 is an air-hardening 9% chromium steel, so it requires careful preheat (typically around 250–300 degrees C) and mandatory post-weld heat treatment (PWHT, a temper around 730–760 degrees C) to temper the hard heat-affected zone and restore toughness. Matching low-hydrogen consumables (e.g. E505 / ER505) and tight control of interpass temperature are used.
Q6. What standards apply to A182 F9 flanges?
A182 F9 flanges are forged to ASTM A182/A182M (Grade F9) and machined to ASME B16.5 (1/2 inch to 24 inch) or ASME B16.47 / MSS SP-44 for larger sizes, with EN 1092-1 for PN-rated flanges. Material is supplied annealed or normalized-and-tempered with EN 10204 3.1 / 3.2 certification. The matching pipe is ASTM A335 P9, casting ASTM A217 C12, fittings ASTM A234 WP9.
Q7. What are the mechanical properties of A182 F9?
Typical ASTM A182 F9 properties: tensile strength 85 ksi (585 MPa) minimum, yield strength 55 ksi (380 MPa) minimum, elongation about 20% minimum, hardness generally below 217 HBW. It is supplied in the normalized-and-tempered (or annealed) condition with strong elevated-temperature and creep properties.
Q8. What temperature can A182 F9 flanges handle?
A182 F9 is used for sustained high-temperature service, commonly up to about 650 degrees C, with good creep strength and the best high-temperature oxidation and sulphidic-corrosion resistance of the standard chrome-moly grades. The exact allowable temperature and pressure follow the applicable code (e.g. ASME B16.5 / B31.3) ratings.
Q9. What industries use A182 F9 flanges?
ASTM A182 F9 flanges are used in oil refining (fired heaters, crude/vacuum and hydroprocessing hot sections), petrochemical processing, power generation (high-temperature boiler, superheater and steam piping), and high-temperature process plant where maximum chrome-moly oxidation and sulphidic-corrosion resistance with creep strength is required.
Q10. Are A182 F9 flanges supplied with material test certificates?
Yes. Every A182 F9 flange is supplied with EN 10204 3.1 (or 3.2) mill test certificates confirming chemistry, mechanical properties, heat-treatment condition and heat/lot traceability, with hardness, hydrostatic testing and third-party inspection on request. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer and exporter from Mumbai, India.