SA 387 GR.22 CL.2 PLATE is having chromium of 2.25% and molybdenum of 1% and ability to work in 600 Deg C temperatures surrounding effectively. The molybdenum and chromium steel plates are working effectively at different temperature continually offering best performance. The addition of molybdenum in SA 387 alloy is increasing the tensile strength of the plates at greater temperature. Also, it is providing excellent corrosion resistance ability and oxidation as well by increasing the lattice strain. This is effectively stopping the corrosive agent from iron dissolving and gives good heat resistance ability and becomes a good choice for gas surrounding. Also, it has good weldability. Thus, this plate is highly demanded globally. Keeping the different needs and requirements of the buyers in mind the industry is providing the product in the different specification that varies in thickness, sizes, length etc. The product that is supplied is offering good properties at high and low temperature. The plates are always supplied at the tempered and normalized condition. The best thing is that the plates are supplied to the buyers at reasonable rates.
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
1. Heat Treatment (The Core Process)
Class 2 requires higher strength than Class 1, achieved through precise thermal cycles:
Normalizing & Tempering (N+T): The plate is heated to 900°C - 960°C for grain refinement, followed by air cooling. It must then be tempered at a minimum of 675°C (1250°F) to enhance ductility.
Quenching & Tempering (Q+T): For heavy-thickness plates, liquid quenching is used to ensure uniform mechanical properties through the core, followed by tempering.
Isothermal Annealing: Sometimes used to provide maximum softness for extreme cold-forming operations.
2. Welding Protocols
Due to its high chromium content, the material is prone to hardening and cracking.
Preheating: Mandatory preheating between 200°C and 300°C is required to prevent cold cracking in the Heat Affected Zone (HAZ).
Post-Weld Heat Treatment (PWHT): Essential for all Class 2 fabrications. Typically performed between 680°C and 720°C to reduce weld hardness and relieve residual stresses.
Consumables: Low-hydrogen electrodes (e.g., E9018-B3) or specific submerged arc wires are required to match the base metal chemistry.
3. Forming and Cutting
Cold Forming: If the strain exceeds 5%, a subsequent stress-relief or full heat treatment is often required to restore properties.
Hot Forming: Usually conducted between 900°C and 1050°C. If hot forming is performed, the material must undergo a full N+T or Q+T cycle afterward to regain its "Class 2" certification.
Thermal Cutting: Plasma or oxy-fuel cutting is common, but the hardened edges must be ground away to remove the heat-affected layer before welding.
4. Required Mechanical Properties (Class 2)
Processing must ensure the following minimum values:
Tensile Strength: 75 – 100 ksi (515 – 690 MPa).
Yield Strength: 45 ksi (310 MPa) minimum.
Elongation: 18% minimum.
5. Testing and Quality Control
Ultrasonic Testing (UT): To detect internal laminations.
Charpy V-Notch Impact Test: To ensure low-temperature toughness.
Step Cooling Test: Often required for refinery vessels to evaluate long-term embrittlement resistance.
Core Applications
This alloy is primarily utilized in sectors requiring sustained performance under extreme thermal stress (up to 600°C):
Petrochemical & Refining: Used for fabrication of hydroprocessing reactors, hydrogenation units, and desalination plants.
Oil & Gas Industry: Essential for storage tanks and process vessels handling "sour gas" (containing hydrogen sulfide), which is highly corrosive to standard steels.
Power Generation: Employed in the construction of industrial boilers, superheaters, steam headers, and turbine casings.
High-Pressure Piping: Used for critical components like heat exchangers, high-temperature ducting, flanges, valves, and pipe clamps.
Key Advantages
Superior High-Temperature Strength: The molybdenum content specifically boosts tensile strength and creep resistance at elevated temperatures, preventing deformation over thousands of hours of work.
Corrosion & Oxidation Resistance: High chromium levels provide a protective layer that resists oxidation and "scaling" in high-heat environments.
Higher Strength (Class 2 vs. Class 1): Class 2 is heat-treated to achieve higher tensile (75–100 ksi) and yield strengths than Class 1, allowing for thinner plate designs in pressure-containing equipment.
Weldability: Despite its high alloy content, it maintains good weldability, which is vital for the complex fabrication of large-scale industrial boilers and vessels.
Cost-Efficiency: It offers a balanced alternative to more expensive stainless steels or high-nickel alloys in environments where moderate corrosion resistance is sufficient.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
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.
Does SA 387 Grade 22 Class 2 have good corrosion resistance?
It has moderate corrosion resistance to oxidation and hydrogen at high temps. For severe corrosive media, additional coating or alloying is needed.
What is the heat treatment process for SA 387 Grade 22 Class 2?
Typically normalized (890-940°C) and tempered (620-675°C) to refine grain structure, improve strength, toughness, and dimensional stability.
Can SA 387 Grade 22 Class 2 be formed by bending or rolling?
Yes, it has good formability. Hot forming (above 900°C) is recommended for thick plates; cold forming is feasible with proper stress relief afterward.
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.
Is SA 387 Grade 22 Class 2 applicable for hydrogen service?
Yes, it is suitable for hydrogen service at high temps due to its chromium-molybdenum composition, which resists hydrogen embrittlement and attack.
What are the surface finish requirements for SA 387 Grade 22 Class 2?
The surface should be free of cracks, scratches, and contaminants. It is usually supplied with a pickled or blasted finish for better weldability and coating adhesion.
What is the tensile strength of SA 387 Grade 22 Class 2 at elevated temperatures?
At 500°C, its tensile strength is about 250 MPa, gradually decreasing with rising temperature but remaining sufficient for designed high-temp loads.
Can SA 387 Grade 22 Class 2 be used in boiler water walls?
Yes, it is commonly used for boiler water walls and superheater tubes, as it withstands high-pressure steam and elevated temps in power plants.