ASTM A182 F11 is a 1.25Cr-0.5Mo forged alloy steel standardized under ASTM A182/A182M for forged or rolled pipe flanges, forged fittings, valves, and parts for high-temperature service. Its UNS designation is K11572. The balanced Cr-Mo alloy content provides a favorable combination of hot tensile strength, hydrogen attack resistance, and fabricability—making F11 the most widely specified forged grade in moderate-temperature refinery and petrochemical service globally. Compared to plain carbon steel forgings, F11 retains 50% higher yield strength at 500°C while maintaining good weldability with matching AWS E8018-B2 / ER80S-B2 consumables. SHUNFU METAL manufactures F11 forged bars from EAF + LF + VD double-refined heats, precision-forged on our 6,000-ton hydraulic press, and quenched-and-tempered to Class 1, 2, or 3 property levels with full digital heat-treatment traceability.
ASTM A182 F11 is a 1.25Cr-0.5Mo low-alloy forged steel supplied by SHUNFU METAL for oil refinery pressure vessels, petrochemical piping, wellhead valve bodies, and steam power plant components. It is the forged-grade counterpart to A335 P11 seamless pipe, delivering excellent elevated-temperature strength up to 550°C with proven resistance to hydrogen attack and oxidation. Available in three classes, F11 forgings are the industry-standard choice for ASME B16.5 flanges, API 6A wellhead bodies, and refinery heater tubesheets where cost-effective Cr-Mo performance is required.
Equivalent & Cross-Reference Grades for F11
| Standard / Designation | Grade / Material | Product Form |
|---|---|---|
| ASTM A182 / ASME SA-182 | F11 Class 1 / 2 / 3 | Forgings |
| ASTM A335 / ASME SA-335 | P11 | Seamless pipe |
| ASTM A234 | WP11 | Buttweld fittings |
| ASTM A217 | WC6 | Cast valve bodies |
| ASTM A387 | Gr.11 Class 1 / 2 | Pressure vessel plate |
| ASTM A213 | T11 | Heat exchanger tube |
| DIN / EN | 13CrMo4-5 / 1.7335 | Forgings & bars |
| JIS G 3203 / G 3458 | SFVAF12A / STPA23 | Forgings / pipe |
| GB (China) | 15CrMo / NB/T 47008 | Forgings & plate |
F11 Applications in Oil & Gas, Refinery & Power
Weld Neck Flanges
Gate & Globe Valve Bodies
Heat Exchanger Tube Sheets
Pressure Vessel Connections
Boiler Drum & Header Forgings
Wellhead Forged Bodies
Steam Turbine Casings
Refinery Furnace Tube Supports
Check Valve Internals
Superheater Headers
Pump & Compressor Casings
Forged Pipe Fittings
F11 Bar Supply Range
SHUNFU METAL supplies ASTM A182 F11 steel in the following forged bar dimensions, produced on our 6,000-ton hydraulic open-die press and GFM radial forging machine:
| Product Form | Diameter / Thickness (mm) | Width (mm) | Length (mm) | Condition |
|---|---|---|---|---|
| Forged Round Bar | 100 – 1,200 | — | 1,000 – 12,000 | N+T or Q+T |
| Hot-Rolled Round Bar | 10 – 500 | — | 3,000 – 9,000 | As-rolled / Annealed |
| Forged Flat Bar | 50 – 500 | 100 – 1,500 | 1,000 – 6,000 | N+T or Q+T |
| Hot-Rolled Flat Bar | 3 – 120 | 20 – 610 | 3,000 – 9,000 | As-rolled / Annealed |
| Forged Rings / Sleeves | OD 200 – 4,000 | Height 50 – 1,000 | Per drawing | Q+T + rough machined |
| Forged Blocks / Discs | Thk 80 – 600 | 200 – 1,500 | 200 – 1,500 | Q+T + machined |
All F11 bars are forged from EAF + LF + VD refined heats at a starting temperature of 1,050–1,200°C with a finishing temperature above 850°C. Forged bars undergo controlled slow cooling in insulated pits to prevent hydrogen-induced flaking. SHUNFU METAL verifies every heat with optical emission spectrometry and provides full melt traceability from ingot to finished bar.
Chemical Composition of ASTM A182 F11 (wt.%)
| Element | F11 Class 1 | F11 Class 2 | F11 Class 3 |
|---|---|---|---|
| Carbon (C) | 0.05–0.15 | 0.10–0.20 | 0.10–0.20 |
| Manganese (Mn) | 0.30–0.60 | 0.30–0.80 | 0.30–0.80 |
| Phosphorus (P) max | 0.030 | 0.040 | 0.040 |
| Sulfur (S) max | 0.030 | 0.040 | 0.040 |
| Silicon (Si) | 0.50–1.00 | 0.50–1.00 | 0.50–1.00 |
| Chromium (Cr) | 1.00–1.50 | 1.00–1.50 | 1.00–1.50 |
| Molybdenum (Mo) | 0.44–0.65 | 0.44–0.65 | 0.44–0.65 |
SHUNFU METAL Controls:
Low residuals: P+S typically ≤0.010% via EAF+LF+VD double refining for Class 3 applications requiring Charpy toughness at −29°C or colder.
Tramp elements (Sn, As, Sb, Pb) controlled to ≤0.010% each to minimize temper embrittlement susceptibility in long-term elevated temperature service.
X-factor = (10P+5Sb+4Sn+As)/100 ≤ 15 ppm and J-factor = (Si+Mn)×(P+Sn)×10&sup4 ≤ 150 per API 934 for critical hydrogen service forgings.
Carbon equivalent CE = C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 typically ≤ 0.62 to ensure field weldability with standard B2 consumables.
Mechanical Properties (ASTM A182)
| Property | Class 1 | Class 2 | Class 3 |
|---|---|---|---|
| Tensile Strength (min) | 415 MPa | 485 MPa | 515 MPa |
| Yield Strength Rp0.2 (min) | 205 MPa | 275 MPa | 310 MPa |
| Elongation in 4D (min) | 20% | 20% | 20% |
| Reduction of Area (min) | 45% | 30% | 30% |
| Brinell Hardness | 121–174 HBW | 143–207 HBW | 156–207 HBW |
Heat Treatment per ASTM A182:
Class 1: Anneal ≥900°C + furnace cool, or Normalize ≥900°C + Temper ≥620°C.
Class 2 & 3: Normalize ≥900°C (air cool) + Temper ≥620°C. Holding time minimum 1 h per 25 mm of maximum cross-section.
All F11 bars produced by SHUNFU METAL are furnace heat-treated with calibrated temperature uniformity surveys (±10°C), automated chart recorders, and full-cycle time-temperature data traceable in every MTC.
NACE MR0175: Max hardness 22 HRC (237 HBW) for sour service when PWHT at ≥620°C after welding.
PWHT per ASME B31.3: 704–746°C, hold 1 h/25 mm, minimum 1 h.
Elevated Temperature Strength (typical N+T): Yield strength at 400°C ≈ 175 MPa; at 500°C ≈ 145 MPa; at 550°C ≈ 110 MPa. Creep rupture strength at 500°C / 100,000 h ≈ 105 MPa—sufficient for most refinery heater and steam piping applications. SHUNFU METAL can supply supplemental CREEP test reports per EN 10291 upon request.
Certifications: EN 10204 3.1 / 3.2 | API Q1 / ISO 9001 | ISO 14001 | OHSAS 18001 | PED 2014/68/EU Annex I Section 4.3 | NORSOK M-650 QTR | UT per SEP 1921 / EN 10228-3 Class 2/3 | MT/PT per ASME BPV Section V | Charpy impact at −29°C to −46°C per ASME B31.3 | PWHT documentation per ASME Section VIII Div.2 | Positive Material Identification (PMI) per API 578
Need ASTM A182 F11 Steel to the specification above?
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