ASTM A182 GRADE F22 LOW-ALLOY STEEL — TECHNICAL DATASHEET AND ENGINEERING REPORT
ASTM A182 Grade F22 (UNS K21590) is a forged and rolled low-alloy steel containing nominally 2.25% chromium and 1% molybdenum. It is primarily specified for the manufacture of pressure piping components, flanges, forged fittings, valves, and related parts intended for elevated temperature and high-pressure service.
F22 serves as a high-performance metallurgical upgrade over standard carbon steels, favored for its deep-hardening capability, excellent high-temperature creep strength, and superior resistance to hydrogen-induced degradation. Note: The maximum forged weight under ASTM A182 is restricted to 10,000 lb (4540 kg); heavier sections must comply with ASTM A336/A336M.
■ Chemical Composition Limits (Weight %)
The mechanical performance and high-temperature stability of F22 are governed by its precise chemical makeup. Below are the standard limits alongside high-integrity API 6A PSL 3 requirements.
| Element | ASTM A182 F22 Class 1 & 3 (%) | API 6A PSL 3 Requirements (%) |
|---|---|---|
| Carbon (C) | 0.05 – 0.15 | 0.08 – 0.15 |
| Chromium (Cr) | 2.00 – 2.50 | 2.00 – 2.50 |
| Molybdenum (Mo) | 0.87 – 1.13 | 0.90 – 1.10 |
| Manganese (Mn) | 0.30 – 0.60 | 0.30 – 0.60 |
| Silicon (Si) | 0.50 max | 0.15 – 0.50 |
| Phosphorus (P) | 0.040 max | 0.025 max |
| Sulfur (S) | 0.040 max | 0.025 max |
■ Proprietary Datasheet Download
ASTM A182 Grade F22 — 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)
Properties are directly linked to the specified class and heat treatment (e.g., annealed vs. normalized/tempered vs. quenched/tempered).
| Mechanical Property | Class 1 (Annealed) | Class 3 (Normalized & Tempered) | API 6A 75K (Quenched & Tempered) |
|---|---|---|---|
| Tensile Strength, min | 60 ksi (415 MPa) | 75 ksi (515 MPa) | 95 ksi (655 MPa) |
| Yield Strength (0.2%), min | 30 ksi (205 MPa) | 45 ksi (310 MPa) | 75 ksi (517 MPa) |
| Elongation in 2 in. (min) | 20% | 20% | 17% - 18% |
| Reduction of Area (min) | 35% | 30% | 35% |
| Brinell Hardness (HBW) | 170 max | 156 – 207 | 197 – 237 |
| Charpy V-Notch Impact | ≥ 27 J at -18°C | ≥ 54 J at 0°C | ≥ 42 J (avg) at -18°C |
■ Physical and Thermal Properties
| Physical Property | Metric Value | Imperial Value |
|---|---|---|
| Density (at 20°C) | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Range | 1420°C – 1450°C | 2588°F – 2642°F |
| Modulus of Elasticity (20°C) | 205 – 210 GPa | 29.7 × 10⁶ – 30.5 × 10⁶ psi |
| Thermal Conductivity (100°C) | 29.5 – 35.9 W/m·K | 204 – 249 BTU·in/(h·ft²·°F) |
| Coefficient of Thermal Exp. (20-100°C) | 11.5 – 11.7 × 10⁻⁶/°C | 6.4 – 6.5 × 10⁻⁶/°F |
■ Pressure-Temperature Ratings (ASME B16.5)
Maximum allowable working pressures (psig) across standard pressure classes:
| Operating Temp (°F) | Class 150 | Class 300 | Class 600 | Class 1500 |
|---|---|---|---|---|
| -20 to 100 | 265 | 695 | 1390 | 3470 |
| 400 | 200 | 640 | 1280 | 3200 |
| 800 | 80 | 510 | 1015 | 2540 |
| 1000 | 20 | 165 | 330 | 825 |
■ Welding and Post-Weld Heat Treatment (PWHT)
Because of its 2.25% chromium content, F22 has high hardenability; rapid cooling from welding temperatures will readily produce a hard, brittle martensitic structure.
- Preheat: Mandatory preheating to 150°C to 315°C (300°F to 600°F) is required to slow the cooling rate and allow dissolved hydrogen to diffuse out.
- Interpass Temp: Maximum interpass temperature is 300°C (570°F) to prevent grain growth.
- PWHT: Strictly mandatory. Heat the joint to 675°C – 760°C (1250°F – 1400°F) and hold for 1 hour per 25 mm of thickness. This tempers martensite, reduces residual stresses, and lowers hardness below the NACE limit of 22 HRC (237 HBW) for sour service compliance.
■ Operating Limits and Engineering Considerations
- Service Limits: Maximum continuous service temperature is 400°C (752°F) for minimal creep. Scaling and degradation threshold is 600°C (1112°F).
- Temper Embrittlement: Between 375°C and 575°C (700°F to 1070°F), F22 is susceptible to temper embrittlement over long exposure times due to impurity segregation. High-temperature vessels often restrict phosphorus to max 0.010% - 0.015%.
- Hydrogen Attack (HTHA): The 2.25% chromium content binds carbon into stable alloy carbides, ensuring resistance to HTHA in high-pressure hydrogen service.
