SA 387 Grade 22 Class 2 is a 2.25Cr-1Mo pressure vessel steel plate specified in ASME SA-387/SA-387M, primarily used for high-temperature and high-pressure service in refineries, petrochemical plants, and power generation facilities; it is produced with controlled chemistry and typically supplied in the normalized and tempered condition to provide good tensile strength, creep resistance, and resistance to hydrogen attack, making it suitable for reactors, heat exchangers, boilers, headers, and other pressure-containing components operating at elevated temperatures.
Equivalent Standards for ASME SA387 Grade 22 Plates
| BS | EN | ASTM / ASME | DIN |
|---|---|---|---|
| 622-515B | 10CrMo9-10 | SA387 Grade 22 Class 2 | 10CrMo9-10 |
Alloy Composition (As per ASME Specification)
| Designation | Nominal Chromium (%) | Nominal Molybdenum (%) |
|---|---|---|
| SA387 Grade 22 | 2.25 | 1.00 |
Tensile Requirements
| Requirement | Value |
|---|---|
| Tensile Strength | 75 – 100 ksi (515 – 690 MPa) |
| Yield Strength (0.2% offset) | ≥ 45 ksi (310 MPa) |
| Elongation in 8 in. (200 mm) | As specified |
| Elongation in 2 in. (50 mm) | ≥ 18% |
| Reduction of Area | 45% (round specimen) / 40% (flat specimen) |
Chemical Composition Requirements
| Element | Heat Analysis | Product Analysis |
|---|---|---|
| Carbon (C) | 0.05 – 0.15 | 0.04 – 0.15 |
| Manganese (Mn) | 0.30 – 0.60 | 0.25 – 0.66 |
| Phosphorus (P) | ≤ 0.035 | ≤ 0.035 |
| Sulphur (S) | ≤ 0.035 | ≤ 0.035 |
| Silicon (Si) | ≤ 0.50 | ≤ 0.50 |
| Chromium (Cr) | 2.00 – 2.50 | 1.88 – 2.62 |
| Molybdenum (Mo) | 0.90 – 1.10 | 0.85 – 1.15 |
Processing and Manufacturing
Processing focuses on achieving a balance between high tensile strength and ductility.
Heat Treatment: Standard delivery for Class 2 is in the Normalized and Tempered (N+T) or Quenched and Tempered (Q+T) condition. Tempering must be performed at a minimum temperature of 1250°F (675°C) to refine the grain structure and stabilize mechanical properties for high-heat service.
Fabrication & Welding: This grade is specifically designed for weldability in pressure vessel construction. However, due to its alloy content, it often requires Simulated Post-Weld Heat Treatment (SPWHT) to ensure the finished assembly maintains its performance in its final operating environment.
Testing Standards: Advanced testing in 2026 includes Positive Material Identification (PMI), intergranular corrosion testing, and Hydrostatic Analysis to guarantee the material is error-free before deployment in high-pressure systems.
Core Advantages
SA 387 Grade 22 Class 2 provides distinct benefits over carbon steels and lower-grade alloys:
Extreme Heat Tolerance: The material maintains its structural integrity and resists deformation at temperatures up to 600°C (1112°F).
Higher Strength Profile: As a Class 2 material, it offers superior tensile strength (75–100 ksi / 515–690 MPa) compared to Class 1, allowing for more robust designs in high-pressure vessels.
Superior Corrosion Resistance: High levels of chromium provide excellent resistance to oxidation and corrosion, while the molybdenum content specifically enhances creep resistance and tensile strength at elevated temperatures.
Sour Service Performance: It is highly effective in sour gas environments (containing hydrogen sulfide, H₂S), where it resists the hazards of hydrogen-induced cracking and deterioration.
Durability and Longevity: The alloy's ability to work continuously for longer durations under high atmospheric pressure makes it a reliable choice for critical infrastructure like nuclear reactors and thermal power plants.
Primary Industrial Applications
Petrochemical Industry: It is a vital material for hydroprocessing reactors, desulfurization equipment, and reforming furnaces. It is specifically chosen for sour service (environments containing hydrogen sulfide, 𝐻2𝑆) because it resists hydrogen corrosion and oxidation at temperatures ranging from 450°C to 550°C.
Power Generation: This grade is used in the construction of ultra-supercritical thermal power boilers, including components like boiler drums, steam headers, turbine casings, and gas turbine waste heat boilers.
Coal Chemical Industry: It is utilized for gasifier shells, methanol synthesis towers, and coke drums that must withstand high pressures (above 30 MPa) and corrosive syngas environments.
Nuclear Sector: Due to its excellent high-temperature strength and hydrogen resistance, it is used for nuclear reactor pressure vessels and liquefied gas storage tanks.
Common Fabricated Components
Fabricators use SA 387 Grade 22 Class 2 to produce a wide range of mission-critical hardware:
Pressure Equipment: Welded boilers, pressure vessels, and heat exchangers.
Piping Systems: High-temperature tubing, flanges, and piping used for transporting heated process fluids.
Hardware & Fittings: High-temperature ducting, pipe clamps, and specialized valves.
Specialized Infrastructure: Offshore and onshore services, shipbuilding, and structural applications like bridges where high durability is required.
Request a professional quotation for SA 387 Grade 22 Class 2 from GNEE Steel.
Is SA 387 Grade 22 Class 2 available in coil form?
It is mainly supplied as plates and sheets. Coil form is rare, as it is primarily used for large pressure vessels requiring plate cutting and forming.
What is the difference between SA 387 Grade 22 Class 2 and SA 387 Grade 11?
Grade 22 has higher chromium (2.25% vs 1.25%) and molybdenum (1% vs 0.5%), offering better high-temp strength and corrosion resistance.
What is the difference between Class 1 and Class 2 of SA 387 Grade 22?
Class 2 requires stricter impact testing (Charpy V-notch) than Class 1, ensuring better toughness, suitable for more demanding high-temperature pressure applications.
What is the minimum thickness available for SA 387 Grade 22 Class 2 steel plates?
The minimum thickness is usually 6 mm, and it can be supplied up to 200 mm or thicker based on custom requirements for large pressure vessels.
What welding consumables are suitable for SA 387 Grade 22 Class 2?
Matching low-alloy consumables like E8018-B2 (stick electrode) or ER80S-B2 (MIG/TIG wire) are used to maintain joint strength and heat resistance.
What is the density of SA 387 Grade 22 Class 2?
Its density is approximately 7.85 g/cm³, the same as ordinary carbon steel, facilitating weight calculation in equipment design.
What testing methods are used for quality control of SA 387 Grade 22 Class 2?
Quality control includes tensile testing, impact testing, hardness testing, ultrasonic flaw detection, and chemical composition analysis to meet ASTM standards.
Can SA 387 Grade 22 Class 2 be machined easily?
It has moderate machinability. Sharp tools, proper cutting speed, and cooling fluids are needed due to its alloy content and high strength.
What is the shelf life of SA 387 Grade 22 Class 2 if stored properly?
If stored in a dry, moisture-free environment with anti-rust coating, its shelf life is unlimited, as it does not degrade under proper storage conditions.