Project Description
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.
Introduction to ASTM A182 F11
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.
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
ASME B16.5 Class 150-2500 flanges for refinery piping up to 550°C
Forged bodies, bonnets, and wedges for API 600/602 high-temperature valves
Forged tube plates for feedwater heaters, condensers, and process exchangers
Nozzle forgings, manway flanges, and body flanges for hydrocracker and hydrotreater reactors
Forged end caps, downcomer connections, and stub forgings for steam drums
API 6A casing and tubing head bodies, bottom connections, and crossover spools
Inner casings, nozzle boxes, and valve chests for HP/IP steam turbines
Forged tube hangers, support plates, and return bends for fired heaters
Forged swing check discs, hinge pins, and seat rings for high-temp process lines
Forged cylindrical headers and branch stub forgings for utility boilers
Forged centrifugal pump casings, discharge heads, and barrel housings
Socket-weld and threaded elbows, tees, couplings, and unions to ASME B16.11
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
