ASTM A182
Grade F9
Forged Flanges & Fittings
Why Grade F9 Sits at the Top of This Ladder
Grade F9 continues the same chromium-molybdenum progression found in Grade F12, F11, and F22 — but at a considerably higher chromium level, 9% rather than the 1–2.25% range covered by those grades. That’s a genuine step change, not an incremental one, and it earns Grade F9 meaningfully superior oxidation resistance and creep strength for the most demanding sustained high-temperature service within the standard low-alloy forging family.
The same two mechanisms driving the whole Cr-Mo family apply here at a stronger level — chromium content well above F22’s forms a more protective, stable oxide layer at elevated temperature, while the 1% molybdenum content continues to resist creep deformation under sustained load. Together, this combination is specifically suited to the highest sustained-temperature ranges these low-alloy grades are designed to reach, before the metallurgy typically transitions to modified 9Cr-1Mo-V grades or full stainless steel for anything further.
Grade F9’s higher chromium content also brings genuine trade-offs worth being direct about — it typically requires more careful control during welding and post-weld heat treatment than the lower-chromium grades in this family, given its more fully martensitic-capable microstructure. Projects specifying F9 should plan for these additional fabrication and welding procedure considerations alongside the material benefit.
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and our Grade F9 flanges and forged fittings are manufactured and verified by chemical composition and mechanical testing under our ISO 9001:2015 quality system.
A Note on Product Scope
ASTM A182 covers forged flanges, fittings, valves, and similar forged pressure-part components — it does not govern nuts or stud bolts, which fall under ASTM A194 and ASTM A193 respectively. If your requirement is for matching stud bolts to pair with F9 flanges, please let us know — we’re glad to discuss suitable matching alloy or stainless fastener grades alongside your F9 forgings.
Where This Grade Genuinely Applies
Superior Oxidation Resistance
9% chromium content forms a considerably more protective oxide layer than F22’s 2.25%.
Superior Creep Strength
Genuinely improved resistance to gradual deformation for the most demanding sustained temperatures.
Highest Standard Cr-Mo Step
The top of the standard low-alloy forging ladder, before modified 9Cr-1Mo-V or full stainless is needed.
Verified Mechanical Properties
Batch testing confirms genuine chromium and molybdenum content and mechanical properties.
Choosing Between Related Forged Alloy Grades
Grade F22
2.25% chromium — genuinely capable, but lower ceiling than F9’s superior high-temperature performance.
View Grade F22 →Grade F9 (This Page)
The highest chromium content in the standard low-alloy Cr-Mo family, for the most demanding service.
You Are HereGrade F11
1.25% chromium — the widely available, moderate-temperature default lower on this same ladder.
View Grade F11 →Grade F22 vs Grade F9 — Quick Reference
Confirming whether service temperature genuinely exceeds F22’s practical ceiling before specifying F9 and accepting its additional welding considerations. This table is the quick reference we use with buyers before quoting.
| Aspect | Grade F22 | Grade F9 |
|---|---|---|
| Chromium Content | ~2.25% | ~9.00% |
| Molybdenum Content | ~1.00% | ~1.00%, identical |
| Welding Complexity | Moderate | Higher, more careful PWHT control |
| Best Suited For | Sustained high temperature | The most demanding sustained high-temperature service |
Grade F9 Specification Details
Nominal Composition
- Chromium 8.00 – 10.00%
- Molybdenum 0.90 – 1.10%
- Carbon ≤0.15%
- UNS Designation K90941
Typical Mechanical Range
- Condition Normalized & Tempered / Annealed
- Service Temperature Highest in Standard Cr-Mo Family
- Creep Strength Genuinely Superior
- Oxidation Resistance Genuinely Superior
Forged Components We Manufacture
- Flanges Weld Neck, Slip-On, Blind, Socket
- Forged Fittings Elbows, Tees, Reducers
- Valve Bodies Forged Components
- Custom Forgings On Request
Application Areas
Wherever the most demanding sustained high-temperature service genuinely exceeds what Grade F22 comfortably handles.
High-Temperature Boiler Piping
boiler system piping
Refinery High-Severity Units
temperature refinery service
Petrochemical Extreme-Temp Units
process flanges and fittings
Power Generation Superheater Piping
piping at highest sustained temp
Standard Export Documentation
Prepared as standard practice for every Grade F9 flange or forged fitting shipment.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Chemical Composition Report
Confirms actual chromium and molybdenum content fall within the specified Grade F9 range.
Certificate of Conformance
Confirms the shipment matches the purchase order grade/size specification in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
NABL Accredited Test Reports
Independent mechanical, dimensional, and NDT testing available on request.
Commercial Invoice & Packing List
Itemized value, Incoterm, and detailed carton/weight breakdown for customs clearance.
Internationally Recognised Standards Coverage
Related Grades & Materials
ASTM A182 Grade F22
Our lower-chromium alternative, a genuinely capable but lower-ceiling option below F9.
View Grade F22 →ASTM A182 Grade F11
Our widely-available, moderate-temperature grade, lower on this same ladder.
View Grade F11 →ASTM A194 Grade 16 Nuts
Our chromium-molybdenum-vanadium high-temperature nut grade, for high-temperature fastening needs.
View Grade 16 Nuts →Stainless Steel Fasteners Manufacturer India
Our broader fastener manufacturing capability across all major carbon, alloy, and stainless grades.
View SS Manufacturer Guide →The Most Demanding
High-Temperature Service?
Tell us your service temperature, pressure class, and welding requirements — we’ll confirm whether Grade F9 fits, and quote with full documentation. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Sales: +91 724 0000 733 · Support: +91 800 9315 333 · sales@akbarfasteners.in