ASTM A182 GRADE F12 ALLOY STEEL FORGINGS — TECHNICAL DATASHEET AND ENGINEERING REPORT
ASTM A182 Grade F12 is a classic 1% Chromium – 0.5% Molybdenum (1Cr–0.5Mo) low-alloy ferritic-bainitic steel widely used in power generation, petrochemical processing, and oil and gas refining. It is designed to bridge the operational gap between basic carbon steels and highly alloyed stainless steels in high-temperature and high-pressure service.
Grade F12 is divided into two distinct classes: Class 1 (UNS K11562) is formulated with a lower carbon and manganese range to optimize ductility and formability, while Class 2 (UNS K11564) incorporates higher carbon and manganese limits to shift the microstructural balance toward tempered bainite, significantly increasing tensile and yield strengths for highly stressed pressure boundaries. Note: The maximum weight of forged components produced under the ASTM A182 specification is strictly limited to 10,000 lb (4,540 kg).
■ Chemical Composition Limits (Weight %)
The chemical design of Grade F12 centers on the precise balance of chromium (for oxidation resistance) and molybdenum (for solid-solution strengthening and creep resistance).
| Element |
Class 1 (UNS K11562) |
Class 2 (UNS K11564) |
| Carbon (C) | 0.05 – 0.15 | 0.10 – 0.20 |
| Manganese (Mn) | 0.30 – 0.60 | 0.30 – 0.80 |
| Phosphorus (P) max | 0.045 | 0.040 |
| Sulfur (S) max | 0.045 | 0.040 |
| Silicon (Si) | 0.50 max | 0.10 – 0.60 |
| Chromium (Cr) | 0.80 – 1.25 | 0.80 – 1.25 |
| Molybdenum (Mo) | 0.44 – 0.65 | 0.44 – 0.65 |
| Nickel (Ni) max | 0.40 | 0.40 |
■ Proprietary Datasheet Download
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ASTM A182 Grade F12 — Complete Technical Yield & Tolerance Datasheet
Contains empirical data for stress simulations, full thermal expansion charts, and advanced piping configuration tables. Corporate/engineering credentials required.
⬇ DOWNLOAD DATASHEET
■ Mechanical Properties (Room Temperature)
| Mechanical Property |
Class 1 (UNS K11562) |
Class 2 (UNS K11564) |
| Tensile Strength (min) | 60 ksi [415 MPa] | 70 ksi [485 MPa] |
| Yield Strength (0.2% offset, min) | 32 ksi [220 MPa] | 40 ksi [275 MPa] |
| Elongation in 2 in. / 50mm (min) | 20.0% | 20.0% |
| Reduction of Area (min) | 45.0% | 30.0% |
| Brinell Hardness Range (HBW) | 121 – 174 | 143 – 207 |
■ Physical and Thermal Performance
| Physical Property |
Value (Metric Units) |
Value (English Units) |
| Density | 7.75 – 7.90 g/cm³ | 0.280 – 0.285 lb/in³ |
| Melting Point | 1400 – 1450 °C | 2550 – 2640 °F |
| Modulus of Elasticity (Young's) | 190 – 210 GPa | 27.5 × 10⁶ - 30.5 × 10⁶ psi |
| Thermal Conductivity (at 400°C) | 44 W/m·K | 26.5 BTU·in/(h·ft²·°F) |
| Mean Coefficient of Thermal Expansion | 13.3 × 10⁻⁶/°C | 7.4 × 10⁻⁶/°F |
| Specific Heat Capacity | 460 – 500 J/kg·K | 0.11 – 0.12 BTU/lb·°F |
■ High-Temperature Strength & Allowable Stress
At high temperatures, Grade F12 transitions from elastic-dominant to creep-rupture-dominant behavior. The allowable design stresses (based on the equivalent JIS SFVAF12 standard) are shown below:
| Service Temperature (°C) |
-10 to 375 |
400 |
425 |
450 |
475 |
500 |
525 |
550 |
575 |
600 |
| Allowable Design Stress (N/mm²) |
121 | 118 | 114 | 91 | 63 | 41 | 27 | 18 | 12 | 8 |
■ ASME B16.5 Class 150 Flange Dimensional Standards
| Nominal Pipe Size (NPS) |
Inside Diameter (in.) |
Outside Diameter (in.) |
Raised Face Diameter (in.) |
Bolt Circle (in.) |
Number of Bolt Holes |
Hole Diameter (in.) |
| 1/2" | 0.88 | 3.75 | 1.38 | 2.62 | 4 | 0.62 |
| 1" | 1.36 | 4.88 | 2.00 | 3.50 | 4 | 0.75 |
| 2" | 2.44 | 6.50 | 3.62 | 5.00 | 8 | 0.75 |
| 4" | 4.57 | 10.00 | 6.19 | 7.88 | 8 | 0.88 |
| 8" | 8.72 | 15.00 | 10.62 | 13.00 | 12 | 1.00 |
| 12" | 12.88 | 20.50 | 15.00 | 17.75 | 16 | 1.25 |
■ Comparative Material Analysis
| Engineering Parameter |
ASTM A182 Grade F12 |
ASTM A182 Grade F22 |
ASME SA387 Grade 11 |
| Primary Alloy Type | 1% Cr – 0.5% Mo | 2.25% Cr – 1% Mo | 1.25% Cr – 0.5% Mo - Si |
| Room Temp. Yield (min) | 275 MPa (40 ksi) | 275 MPa (40 ksi) | 310 MPa (45 ksi) |
| Thermal Conductivity | 44 W/m·K (High) | 33 W/m·K (Moderate) | 39 W/m·K (Moderate) |
| Max. Operating Temp. | 540°C (1000°F) | 590°C (1100°F) | 590°C (1100°F) |
| Creep Rupture Strength | Moderate (~65 MPa @500°C) | High (~95 MPa @500°C) | Very Good (~80 MPa @500°C) |
Thermal Advantage: Grade F12 possesses a thermal conductivity of 44 W/m·K, which is ~33% higher than that of Grade F22. This makes Grade F12 highly effective for heat transfer components (like heat exchangers), reducing local thermal gradients, transient thermal stresses, and the risk of thermal fatigue during rapid start-up or shutdown cycles.
■ Engineering Recommendations and Fabrication
- Class Selection: Specify Class 2 (UNS K11564) for primary pressure boundaries to leverage its higher yield strength (275 MPa min). Class 1 (UNS K11562) should be restricted to applications requiring high ductility or heavy post-forming processing.
- Weight Constraints: Ensure single forged component weight does not exceed 10,000 lb (4,540 kg). If exceeded, transition to ASTM A336/A336M.
- Weld Preheating: Mandatory minimum preheat of 150°C to 175°C (300°F to 350°F) to prevent hydrogen-induced cracking and the formation of brittle untempered martensite in the HAZ. Maximum interpass temperature is 315°C (600°F).
- Post-Weld Heat Treatment (PWHT): To avoid tempering near the lower critical transformation temperature (Ac₁), specify a narrow-target PWHT range of 1200°F to 1300°F (650°C to 704°C). This achieves optimal stress relaxation and HAZ softening without entering the intercritical region that could degrade creep-rupture strength.
