What Is ASTM A182 F11?
F11 is a 1.25Cr-0.5Mo low-alloy steel forging in ASTM A182. Chromium-molybdenum (Cr-Mo) steels keep their strength and oxidation resistance at elevated temperatures, which is why F11 is used for refinery and power piping.
Temperature Range
Cr-Mo forgings of this family are rated up to 538°C in the ASME B16.5 pressure-temperature tables, well above carbon steel limits.
Material Group (per ASME B16.5)
Per ASME B16.5-2025 Table 1A, A182 Gr. F11 Class 2 (1.25Cr-0.5Mo-Si) belongs to Material Group 1.9.
Corrosion Resistance
Cr-Mo alloy steels are chosen for high-temperature strength and oxidation resistance, not for corrosion — their aqueous corrosion behavior is broadly similar to carbon steel (no separate alloy-steel rating row exists in the Schweitzer tables; for corrosive media use the stainless grades above). At temperature they resist scaling better than plain carbon steel.
Typical Applications
- Refinery and petrochemical high-temperature flanges and fittings
- Power boiler and steam piping components
- ASME B16.5 flanges and B16.47 large-diameter flanges for hot service
Chemistry & Mechanical Properties
Cr-Mo composition and mechanical properties per ASTM A182 — consult the standard for exact limits. 3.1 mill certificates supplied.
Related Standards
- ASME B16.5 — Pipe Flanges (NPS 1/2–24)
- ASME B16.47 — Large-Diameter Flanges (NPS 26–60)
- ASTM A182 F22 — 2.25Cr-1Mo Alloy Steel
- ASTM A105 — Carbon Steel Forgings
- Our Flange Range
FAQ
What temperature range does F11 cover?
Up to 538°C per the ASME B16.5 Group 1.9 pressure-temperature tables.
What is F11 used for?
High-temperature piping in refineries, boilers and steam service, where carbon steel loses strength or scales.
Is F11 corrosion-resistant?
No — it is a high-temperature alloy, not a corrosion alloy. Use 304/316 stainless for corrosive aqueous service.
F11 or F22 — which to choose?
F22 (2.25Cr-1Mo) carries higher allowable stresses at temperature; F11 is the lighter, lower-cost option. Confirm against your design temperature and code case.
Is F11 a stainless steel?
No. F11 is a 1.25Cr-0.5Mo low-alloy ferritic steel chosen for high-temperature strength, not corrosion — specify 304/316 for corrosive service.
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