ASTM A182 F11 Alloy Steel Fittings – A182 Gr F11 (1¼Cr-½Mo) Forged Fittings
ASC LLP, Mumbai, supplies ASTM A182 F11 alloy steel fittings: forged socket-weld and threaded fittings to ASME B16.11 in Class 2000 to 9000, together with branch outlets. In addition, every fitting carries an EN 10204 3.1 certificate. This page therefore covers the A182 F11 material in full, including chemical composition, Class 1, 2 and 3 properties, heat treatment, equivalents and matching grades.
What is ASTM A182 F11 Material?
ASTM A182 (ASME SA182) is the specification for forged or rolled alloy and stainless steel pipe flanges, forged fittings, valves and parts for high-temperature service. Within it, Grade F11 is a 1¼% chromium – ½% molybdenum steel with added silicon (UNS K11572 for Classes 2 and 3). As a result, F11 offers good creep strength and oxidation resistance for steam service. However, it is not a corrosion-resistant steel like stainless steel.
F11 is ordered in three strength classes. Class 1 has lower carbon and lower strength, while Class 2 is the grade most piping specifications call for. Class 3, in turn, is the highest-strength version. For this reason, always state the class on the order, for example “ASTM A182 F11 Cl.2”.
A182 F11 – Quick Facts
- Specification: ASTM A182 / ASME SA182, Grade F11 Class 1, 2 or 3
- Composition: 1.00–1.50% Cr, 0.44–0.65% Mo, 0.50–1.00% Si
- Class 2 strength: 485 MPa tensile / 275 MPa yield min
- Fittings standard: ASME B16.11 (socket weld and threaded), MSS SP-97 (branch outlets)
- Matching pipe: ASTM A335 P11
- Service: steam and high-temperature service, typically up to about 565 °C
ASTM A182 F11 Chemical Composition
| Element (%) | F11 Class 1 | F11 Class 2 & 3 |
| Carbon (C) | 0.05 – 0.15 | 0.10 – 0.20 |
| Manganese (Mn) | 0.30 – 0.60 | 0.30 – 0.80 |
| Phosphorus (P) | 0.030 max | 0.040 max |
| Sulphur (S) | 0.030 max | 0.040 max |
| Silicon (Si) | 0.50 – 1.00 | 0.50 – 1.00 |
| Chromium (Cr) | 1.00 – 1.50 | 1.00 – 1.50 |
| Molybdenum (Mo) | 0.44 – 0.65 | 0.44 – 0.65 |
Unlike F22, F11 has two chemistries. Class 1 has lower carbon and tighter phosphorus and sulphur limits, whereas Classes 2 and 3 allow more carbon and manganese, which gives them their higher strength. In addition, the 0.50–1.00% silicon improves oxidation resistance at temperature.
A182 F11 Mechanical Properties – Class 1, 2 & 3
| Property | F11 Class 1 | F11 Class 2 | F11 Class 3 |
| Tensile strength, min | 415 MPa (60 ksi) | 485 MPa (70 ksi) | 515 MPa (75 ksi) |
| Yield strength, min | 205 MPa (30 ksi) | 275 MPa (40 ksi) | 310 MPa (45 ksi) |
| Elongation in 50 mm, min | 20% | 20% | 20% |
| Reduction of area, min | 45% | 30% | 30% |
| Hardness (HBW) | 121 – 174 | 143 – 207 | 156 – 207 |
These are minimum values, so A182 sets no upper tensile limit. However, A182 has no impact-test requirement for F11; therefore, toughness testing is added only when the order asks for it.
A182 F11 Forged Fittings – ASME B16.11 Classes & Sizes
| Fitting type | Class 2000 | Class 3000 | Class 6000 | Class 9000 |
| Socket-weld fittings | – | NPS ⅛ – 4 (SCH 80) | NPS ⅛ – 2 (SCH 160) | NPS ½ – 2 (XXS) |
| Threaded fittings | NPS ⅛ – 4 (SCH 80) | NPS ⅛ – 4 (SCH 160) | NPS ⅛ – 2 (XXS) | – |
The B16.11 class tells you which pipe schedule the fitting suits. For example, a Class 3000 socket-weld fitting matches SCH 80 pipe, while a Class 6000 fitting matches SCH 160. By contrast, larger buttweld elbows, tees and reducers in F11 chemistry are ordered as A234 WP11 fittings.
A182 F11 Fitting Types We Supply
- Socket-weld fittings: 90° and 45° elbows, tees, crosses, couplings, half couplings, reducers, caps and unions
- Threaded (NPT) fittings: elbows, tees, couplings, caps, as well as hex plugs, bushings and unions
- Nipples: swage nipples and hex nipples, with plain, bevelled or threaded ends
- Branch outlets: Weldolet, Sockolet, Threadolet, Elbolet and Nipolet to MSS SP-97
- Bosses and special forgings: also machined to drawing on request
ASTM A182 F11 Fittings Specifications
| Item | Details |
| Specification | ASTM A182 / ASME SA182, Grade F11 Class 1, 2 or 3 |
| Fitting standard | ASME B16.11; MSS SP-97 for outlets; also MSS SP-83 for unions |
| Pressure class | 2000, 3000, 6000 and 9000 |
| Size | NPS ⅛ to 4 (by class); outlets up to 24″ run size |
| Ends | Socket weld (SW), threaded NPT; also butt-weld outlets |
| Heat treatment | Annealed, or normalised and tempered at 620 °C (1150 °F) min |
| Testing | Chemistry, tensile and hardness; in addition, PMI, UT and third-party inspection on request |
| Certificate | EN 10204 3.1; also 3.2 on request |
A182 F11 Equivalent & Matching Grades
| Product | Matching F11 / 1¼Cr-½Mo grade |
| Seamless pipe | ASTM A335 P11 |
| Buttweld fittings | ASTM A234 WP11 |
| Flanges | ASTM A182 F11 flanges |
| Heavy forgings | ASTM A336 F11 |
| Boiler / heat exchanger tubes | ASTM A213 T11 |
| Valve castings | ASTM A217 WC6 |
| EN forging grade (approximate) | EN 10222-2 13CrMo4-5 (1.7335) |
Because these grades share the same 1¼Cr-½Mo base, a P11 line can be built with F11 forged fittings, WP11 buttweld fittings and F11 flanges. However, 13CrMo4-5 has lower silicon than F11, so treat it as a close equivalent and check it against your piping specification.
A182 F11 Heat Treatment & Welding
- Heat treatment: F11 is annealed, or normalised and then tempered at 620 °C (1150 °F) minimum, so it reaches the strength of the ordered class.
- Welding: F11 is a P-No. 4 material; therefore, it needs preheat (typically about 150 °C) and post-weld heat treatment, usually around 650–730 °C.
- Filler metal: 1¼Cr-½Mo consumables such as E8018-B2 / ER80S-B2 are normally used.
- Hardness after welding: in addition, many specifications check weld and HAZ hardness after PWHT.
Applications of ASTM A182 F11 Fittings
| Industry | Typical A182 F11 fitting use |
| Power generation | Steam, drain and vent lines, as well as boiler connections |
| Refining | Furnace and high-temperature process lines, while temperatures stay below about 565 °C |
| Petrochemical | Cracker and reformer piping in Cr-Mo service |
| Boilers & HRSG | Instrument and drain connections on Cr-Mo headers |
| Heat exchangers | Nozzle and small-bore connections on Cr-Mo equipment |
F11 is generally used up to about 565 °C. Above that, or where hydrogen service needs more chromium, F22 or F91 is used instead. Since F11 is a low-alloy steel, it is not chosen for corrosion resistance; therefore, wet corrosive service still needs stainless or nickel alloys.
A182 F11 vs F22 vs F91
| Grade | Cr – Mo | Class 3 / typical tensile – yield (MPa) | Typical use |
| A182 F11 | 1¼Cr – ½Mo | 515 – 310 | Steam lines up to about 565 °C |
| A182 F22 | 2¼Cr – 1Mo | 515 – 310 | Steam and hydrogen service up to about 595 °C |
| A182 F91 | 9Cr – 1Mo – V | 585 – 415 | Supercritical power plants, up to about 650 °C |
In short, F11 is the economical Cr-Mo grade for steam service, while F22 and F91 are chosen for higher temperatures. See also our F1, F5 and F9 fittings, the A234 WP alloy fittings range and our alloy steel products. For flange bolting, see A193 B7 stud bolts.
Frequently Asked Questions – ASTM A182 F11 Fittings
What is ASTM A182 F11 material?
ASTM A182 F11 is a forged 1¼% chromium – ½% molybdenum alloy steel for high-temperature service. It is used for forged fittings, flanges and valve parts in steam and power piping.
What is the chemical composition of A182 F11?
F11 contains Cr 1.00–1.50%, Mo 0.44–0.65% and Si 0.50–1.00%. However, carbon is 0.05–0.15% for Class 1 and 0.10–0.20% for Classes 2 and 3, while Mn is 0.30–0.60% and 0.30–0.80% respectively.
What is the difference between F11 Class 1, 2 and 3?
The classes differ in chemistry and strength. For example, Class 1 has 415 / 205 MPa tensile / yield, Class 2 has 485 / 275 MPa, and Class 3 has 515 / 310 MPa.
What is the equivalent of ASTM A182 F11?
The UNS number for F11 Class 2 is K11572, and the closest EN forging grade is 13CrMo4-5 (1.7335). In addition, the matching grades are A335 P11 pipe, A234 WP11 fittings and A217 WC6 castings.
What is the maximum temperature for F11?
F11 is generally used up to about 565 °C (1050 °F). Above that, F22 or F91 is usually chosen instead.
Which pipe is used with A182 F11 fittings?
A182 F11 fittings are normally used with ASTM A335 P11 seamless pipe. Therefore, F11 flanges and WP11 buttweld fittings are used on the same line.
Is A182 F11 corrosion resistant?
No. F11 is a low-alloy Cr-Mo steel, so it is chosen for strength and oxidation resistance at high temperature rather than corrosion resistance.
Global Supply
ASC LLP supplies ASTM A182 F11 forged fittings from Mumbai to customers in India, the Middle East, Europe, Africa, the Americas and South-East Asia, together with matching P11 pipe and F11 flanges. To get a prompt quotation, simply send your enquiry with fitting type, size, B16.11 class, F11 class (1, 2 or 3) and quantity.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
