What is SA387 Grade 22?
ASME SA387 Grade 22 is a chromium-molybdenum (2.25Cr–1Mo) alloy steel plate engineered for high-temperature pressure service. Boasting superior high-temperature strength, oxidation resistance and creep resistance, this steel grade is widely used for equipment operating under continuous high temperatures, such as refinery reactors, heat exchangers, boilers, pressure vessels and power generation equipment.
In accordance with ASME SA387 / ASTM A387 specifications, SA387 Grade 22 is available in two classes: Class 1 and Class 2. The two classes have essentially identical chemical compositions; their primary differences reside in mechanical property requirements and as-delivered heat treatment conditions. Class 2 material is supplied in the normalized and tempered (N+T) condition, with higher minimum tensile and yield strengths than Class 1, rendering it the preferred material for pressure vessel service involving more severe operating conditions.
What Are the Elevated Temperature Properties of ASME SA387 Grade 22?
Synergistic chromium and molybdenum alloying elements in SA387 Grade 22 precipitate stable carbides. At 593°C, these carbides effectively pin grain boundaries and hinder hydrogen atom ingress, providing the steel with excellent creep resistance and elevated-temperature creep rupture strength.
Chromium (Cr) present in SA387 Grade 22 steel plates generates a compact Cr₂O₃ passivating film, significantly improving the material's resistance to high-temperature oxidation.
Molybdenum (Mo) inhibits hydrogen diffusion. When deployed in high-temperature hydrogen service environments including hydrotreating reactors, this steel exhibits excellent resistance to hydrogen embrittlement, high-temperature hydrogen attack (HTHA), hydrogen blistering and sulfide corrosion, and surpasses standard low-alloy steels in resistance to hydrogen-induced corrosion.
After normalized plus tempered (N+T) heat treatment (normalizing temperature ≤ 968°C, tempering temperature ≥ 720°C), SA387 Grade 22 achieves a bainitic microstructure fraction of no less than 90% in its matrix. This ensures microstructural homogeneity and thermal stability during high-temperature service and greatly reduces susceptibility to temper embrittlement.
Specification of ASME SA387 Grade 22
| Item | Specification |
|---|---|
| Product Name | ASME SA387 Grade 22 Alloy Steel Plate |
| Standard | ASME SA387 / ASTM A387 |
| Grade | Grade 22 (2.25Cr–1Mo) |
| Available Class | Class 1, Class 2 |
| Steel Type | Chromium-Molybdenum Alloy Pressure Vessel Steel |
| Heat Treatment | Class 1: Annealed or Normalized*Class 2: Normalized and Tempered |
| Thickness | 6–300 mm |
| Width | 1,500–4,000 mm |
| Length | 3,000–18,000 mm |
| Applications | Pressure Vessels, Boilers, Heat Exchangers, Hydroprocessing Reactors, Steam Drums, Refinery Equipment, Petrochemical Equipment, Power Plant Components |
Chemical Composition of ASME SA387 Grade 22
| Element | Heat Analysis | Product Analysis |
|---|---|---|
| C | 0.05‑0.15 | 0.04‑0.15 |
| Mn | 0.30‑0.60 | 0.25‑0.66 |
| Si | ≤0.50 | ≤0.50 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.025 | ≤0.025 |
| Cr | 2.00‑2.50 | 1.88‑2.62 |
| Mo | 0.90‑1.10 | 0.85‑1.15 |
Mechanical Property of ASME SA387 Grade 22
| Property Index | ASTM A387 Gr.22 Class 2 | ASTM A387 Gr.22 Class 1 |
|---|---|---|
| Tensile Strength, MPa | 515‑690 | 415‑585 |
| Min Yield Strength (0.2 % offset), MPa | 310 | 205 |
| Min Elongation (50 mm gauge length) | 18 % | 18 % |
| Reduction of Area (round specimen), min | 45 % | 45 % |
| Reduction of Area (flat specimen), min | 40 % | 40 % |
| Typical As‑delivered Brinell Hardness | 180‑210 HB | 170‑195 HB |
| Max Allowed Hardness after SPWHT | ≤220 HB (mandatory for sour service) | ≤220 HB |
ASME SA387 Grade 22 Price
| Description | Price |
| SA 387 Gr 22 Hot Rolled Steel Plates | US$ 710-800 / Ton |
| ASME SA-387 Gr. 22 Cl. 1 Cl. 2 Pressure Vessel Steel Weight Lifting Plates | US$ 700-800 / Ton |
| SA 387 Grade 22 Plates | US$ 690-790 / Ton |
| sa387 22 Plates | US$ 710-800 / Ton |
|
Astm A387 Gr22 Plates |
US$ 700-800 / Ton |
| Alloy Steel Plates SA 387 GR 22 CL.2 | US$ 690-790 / Ton |
| SA387 Grade 22 Class 2 Steel Plates | US$ 710-800 / Ton |
| Alloy Steel Grade 22 Sheet Plates | US$ 700-800 / Ton |
| Sa 387 Gr 22 Cl 2 Plates | US$ 690-790 / Ton |
High Temperature Performance Comparison of SA387 Gr.11 vs SA387 Gr.22 vs SA387 Gr.91 vs 10CrMo910
| Property | SA387 Gr.11 | SA387 Gr.22 | SA387 Gr.91 |
10CrMo9-10 |
|---|---|---|---|---|
| Standard | ASTM A387 / ASME SA387 | ASTM A387 / ASME SA387 | ASTM A387 / ASME SA387 | EN 10028-2 |
| Alloy Type | 1.25Cr–0.5Mo | 2.25Cr–1Mo | 9Cr–1Mo–V–Nb | 2.25Cr–1Mo |
| Carbon (Max., %) | 0.15 | 0.15 | 0.12 | 0.14 |
| Chromium (Cr, %) | 1.00–1.50 | 2.00–2.50 | 8.00–9.50 | 2.00–2.50 |
| Molybdenum (Mo, %) | 0.45–0.65 | 0.90–1.10 | 0.85–1.05 | 0.90–1.10 |
| Vanadium (V, %) | - | - | 0.18–0.25 | - |
| Niobium (Nb, %) | - | - | 0.06–0.10 | - |
| Tensile Strength (MPa) | 415–585 (Class 2) | 585–760 (Class 2) | 585–760 |
480–620 |
| Yield Strength (MPa) | ≥240 (Class 2) | ≥310 (Class 2) | ≥415 |
≥300 |
| Heat Treatment | Normalized & Tempered | Normalized & Tempered | Normalized & Tempered | Normalized & Tempered |
| Creep Strength Range | Medium | High | Very High | High |
| High Temperature Service Range (Approx.) | 400–550°C | 450–600°C | 550–650°C+ | 450–600°C |
| Oxidation Resistance | Cr₂O₃ protective layer (1–1.5% Cr) | Improved Cr₂O₃ protection (2–2.5% Cr) | High Cr oxidation resistance | Similar to SA387 Gr.22 |
Among these Cr-Mo alloy steels, SA387 Grade 22 occupies a balanced position between SA387 Grade 11 and Grade 91. Its 2.25Cr–1Mo alloy composition provides higher temperature strength and creep resistance than Grade 11, while maintaining better weldability and fabrication performance compared with Grade 91. This makes it one of the most widely selected materials for high-temperature pressure vessels, reactors and heat exchangers.
Typical Applications of ASME SA387 Grade 22
- Hydroprocessing equipment: hydrocracking reactors, hydrotreating reactors, desulfurization reactors
- Heat exchangers: shells, heads, and pressure-bearing components of high-temperature heat exchangers
- Boilers and steam equipment: boiler drums, steam separators, high-temperature pressure components
- Refining and petrochemical pressure vessels: reactors, process vessels, separators, fractionation equipment
- Heating equipment: pressure-bearing components subject to high thermal loads
- Power generation equipment: steam-related pressure vessels, heat recovery equipment
Why Choose GNEE Steel?
Quality Documentation & Testing Support
For pressure vessel applications, complete material documentation is essential. GNEE Steel can provide supporting documents and testing services according to customer requirements, including:
- Mill Test Certificate (MTC)
- Chemical composition report
- Mechanical property test results
- Ultrasonic testing (UT)
- Third-party inspection support
Dimension & Surface Requirements
According to project specifications, GNEE Steel can support:
- Customized thickness and width requirements
- Surface condition requirements
- Dimensional inspection
- Plate traceability
This helps customers receive steel plates ready for further fabrication.
GNEE Steel has been active in the pressure vessel plate sector for 18 years. Backed by professional expertise and a skilled technical team, we offer customized products and provide processing and cutting services to meet diverse customer requirements. Every batch of steel plates we produce comes with a quality inspection certificate.
FAQ
Q: What is the difference between ASME SA387 Gr.22 Class 1 and Class 2 at high temperatures?
A: While both ASME SA387 Grade 22 Class 1 and Class 2 share the same nominal chemical composition (2.25% Chromium and 1.0% Molybdenum), they feature different heat treatments SA387 Grade 22 Class 2. Consequently, Class 2 provides significantly higher tensile and yield strength at both room and elevated temperatures compared to Class 1 SA387/A387 Plate.
Q: What is the maximum service temperature of SA387 Grade 22?
A: The maximum recommended service temperature for ASME SA387 Grade 22 (achromium-molybdenum alloy steel) is typically 600°C (1112°F). In continuous high-temperature pressure vessel and industrial boiler applications, engineers typically limit itsoperation to between 550°C and 600°C to prevent degradation of its mechanicalproperties and oxidation resistance.
Q: Is SA387 Grade 22 better than Grade 11 for high-temperature pressure vessels?
A: Yes, SA387 Grade 22 is generally considered better than Grade 11 for extreme high-temperature and high-pressure environments. It offers superior creep resistance, higher tensile strength, and better oxidation resistance in the most critical applications.
Q: Does SA387 Grade 22 require PWHT after welding?
A: Yes. Under ASME Section VIII, Div. 1 (UCS-56), SA-387 Grade 22 (a P-No. 5B material) essentially always requires Post-Weld Heat Treatment (PWHT).
