What is ASTM A387 Gr.22 Cl2?
In the ASTM A387 specification, Grade 11 (1.25Cr-0.5Mo) and Grade 22 (2.25Cr-1Mo) are the two most widely specified grades. However, many procurement professionals are unaware that when the design temperature exceeds 450°C in hydrogen service, Grade 11 reaches its operational limit for HTHA (High-Temperature Hydrogen Attack) resistance, necessitating an upgrade to Grade 22. Selecting the incorrect grade can shorten equipment service life at best, or lead to catastrophic safety failures at worst.
ASTM A387 Grade 22 Class 2 is a chromium-molybdenum alloy steel engineered for elevated-temperature pressure vessel applications. Featuring 2.25% chromium and 1% molybdenum, ASTM A387 Gr.22 CL2 pressure vessel plates deliver an effective service temperature up to 600°C. Consequently, our plates offer superior corrosion and oxidation resistance under high-stress conditions. Our Gr.22 steel plates can be supplied in various product forms, including heavy plates, hot-rolled coils, blanks, and custom profile cuts for flanges, dished heads, and rings. GNEE Steel maintains a comprehensive inventory of A387 Gr.22 CL2 plates across a wide range of dimensions and thicknesses, ready for global distribution.
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Specification
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Product Name |
ASTM A387 Gr.22 CL2 Hot Rolled Carbon Steel Plate |
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Material |
ASTM A387 Gr.22 CL2 |
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Specification |
Width: 500-2000mm Length: 1000-12000mm |
|
Package |
Standard seaworthy package (wooden crate package and other package or according to your requirement) |
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Standard |
ASTM A387 |
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Delivery time |
A.7 days if these products are in stock.B.20 days if these products will be produced after the order |
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Mechanical Property
| A387 / SA387 Grade 22 | Class 2 |
| Tensile Strength (ksi) | 75-100 |
| Tensile Strength (MPa) | 515-690 |
| Yield Strength (ksi) | 45 |
| Yield Strength (MPa) | 310 |
| Elongation in 200mm (%) | – |
| Elongation in 50mm (%) | 18 |
| Reduction of area in % | 45 |
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Chemical Composition
| Grade | C | Mn | P | S | Si | Cr | Mo |
| A 387 Gr. 22 | 0.04 – 0.15 | 0.25 – 0.66 | 0.035 | 0.035 | 0.5 max | 1.88 – 2.62 | 0.85 – 1.15 |
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Equivalent Material
| ASTM/ASME | BS | EN | DIN |
| A387-22-2 | 622-515B | 10 CRMO 910 | 10 CRMO 910 |
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Tolerance
| Nominal thickness | Maximum thickness difference within a plate | |||||
| Nominal width | ||||||
| > 2000 < 2500 | > 600 < 2000 | > 2500 < 3000 | > 3500 < 4000 | > 3000 < 3500 | > 4000 | |
| > 5 < 8 | 0.9 | 0.9 | 1.0 | - | 1.0 | - |
| > 3 < 5 | 0.9 | 0.8 | 0.9 | - | - | - |
| > 80 < 150 | 1.4 | 1.3 | 1.5 | 1.6 | 1.5 | 1.7 |
| > 15 < 25 | 1.1 | 1.0 | 1.2 | 1.3 | 1.2 | 1.4 |
| > 150 < 250 | 1.5 | 1.4 | 1.6 | 1.7 | 1.6 | - |
What are the high-temperature properties of ASTM A387 Gr. 22 Cl. 2?
The exceptional elevated-temperature performance of ASTM A387 Grade 22 Class 2 steel is attributed to its 2.25Cr-1.0Mo alloy system. With a chromium content of 2.00–2.50% and a molybdenum content of 0.90–1.10% (fully compliant with the ASTM A387/A387M specification), this steel offers superior oxidation resistance, creep strength, and microstructural stability compared to leaner-alloy Cr-Mo steels, such as Grade 11.
Our ASTM A387 Gr. 22 Cl. 2 plates are typically specified for continuous service within a temperature range of 350°C to 550°C. While short-term exposure up to approximately 600°C may be permissible, the maximum use temperature limit must always comply with the regulations outlined in the ASME BPVC (Boiler and Pressure Vessel Code), Section II, Part D.
The high-temperature properties of Grade 22 Class 2 are heavily dependent on the mandatory Normalized and Tempered (N+T) delivery condition required by the ASTM A387 standard. Proper heat treatment refines the microstructure and promotes the precipitation of stable chromium-molybdenum carbides, thereby enhancing creep-rupture resistance, toughness, and long-term service reliability.
At GNEE Steel, all steel plates supplied in accordance with ASTM A387 Gr. 22 Class 2 are manufactured using strictly controlled heat treatment processes. Material properties are verified through tensile testing, impact testing (where specified), and comprehensive quality inspections compliant with ASTM A387 and ASTM A20 standards. We can also provide EN 10204 3.1/3.2 certification, heat-treatment records and third-party inspection (SGS, TÜV, BV) to ensure full material traceability for critical pressure vessel projects.
Comparison: ASTM A387 Gr.22 Class 2 vs A387 Gr.11 Class 2 vs A387 Grade 91
| Comparison Item | ASTM A387 Gr.22 Class 2 | ASTM A387 Gr.11 Class 2 | ASTM A387 Grade 91 |
|---|---|---|---|
| Nominal Cr Content | ~2.25% | ~1.25% | ~9.0% |
| Nominal Mo Content | ~1.00% | ~0.50% | ~1.0% + V, Nb |
| Minimum Yield Strength | 310 MPa | 310 MPa | 415 MPa |
| Tensile Strength | 515–690 MPa | 515–690 MPa | 585–760 MPa |
| Typical Maximum Service Temperature* | ~600°C | ~550°C | ~650°C |
| Creep Resistance | ★★★★☆ | ★★★☆☆ | ★★★★★ |
| Hydrogen Resistance | Excellent | Moderate | Excellent |
| Relative Material Cost | Medium | Low | High |
Six Core Advantages
Higher Chromium Content (~2.25%) - Significantly enhances elevated-temperature oxidation and corrosion resistance, delivering premium-tier performance on par with Grade 91 by nearly doubling the chromium content of Grade 11 (~1.25%).
Higher Molybdenum Content (~1.00%) - Effectively boosts high-temperature strength, creep resistance, and thermal stability, ensuring superior long-term service reliability by doubling the molybdenum content compared to Grade 11 (~0.50%).
Elevated Maximum Service Temperature (~600°C) - Expands application boundaries to cover a wider range of mid-to-high temperature operating conditions by operating approximately 50°C higher than Grade 11 (~550°C).
Outstanding Creep Resistance - Stands far superior to Grade 11, minimizing creep deformation under long-term, high-temperature structural loads to significantly extend equipment design life.
Exceptional Cost-Effectiveness - Maintains a highly competitive mid-range cost profile compared to high-cost Grade 91, delivering a significantly superior value proposition for applications operating below 600°C.
Enhanced Weldability and Fabricability - Provides a balanced alloy chemistry compared to Grade 91 (which features ~9.0% Cr plus V/Nb micro-alloying). This results in much lower weld cracking susceptibility and more manageable Post-Weld Heat Treatment (PWHT) parameters.
ASTM A387 Gr.22 CL2 Hot Rolled Steel Plate Typical Applications
Petrochemical & Refining:
- Hydrocracking Reactors
- Catalytic Reformers
- Coke Drums
- Thermal Separators
- Pressure Vessels in Hydrogen Service
Power Generation:
- Boiler Drums
- Superheater Headers
- High-Temperature Steam Piping
- Industrial Heat Exchangers
Oil & Gas:
- High-Pressure Separators (Onshore/Offshore)
- LPG Storage Tanks
- Sour Service Piping
Chemical Processing:
- Ammonia Synthesis Converters
- Methanol Reactors
- Sulfur Recovery Units (SRU)
- High-Temperature Heat Exchangers
Why Choose GNEE Steel?
Ample Inventory & Flexible Supply Capabilities
Our ASTM A387 Gr. 22 Cl. 2 steel plates are available in a comprehensive range of thicknesses, widths, and lengths. We guarantee rapid delivery for standard dimensions and offer custom rolling tailored to specific project requirements.
Precision Value-Added Processing Services
To minimize lead times and reduce downstream fabrication costs for our clients, we provide advanced processing services including CNC oxy-fuel cutting, plasma cutting, edge preparation, beveling, drilling, plate rolling, and custom profile cutting.
Export-Grade Maritime Packaging
All steel plates undergo the application of rust-preventative coatings and are secured with waterproof wrapping, heavy-duty steel strapping, and sea-worthy wooden crating/skidding to ensure maximum product integrity during international ocean transit.
Turnkey Sourcing Solutions
Beyond ASTM A387 Grade 22 Class 2, GNEE Steel supplies a complete portfolio of pressure vessel plates-including ASTM A387 Grade 11, Grade 5, Grade 9, as well as ASTM A516 and ASTM A537-enabling clients to streamline their supply chains and optimize total procurement costs.
Do you require a customized product solution? GNEE Steel offers a one-stop service ranging from raw plate supply to CNC cutting, edge beveling, heat treatment, ultrasonic testing (UT), third-party inspection (SGS/BV/TÜV), and global logistics. You are welcome to bring your drawings for consultation to receive a quick quote.
FAQ
Q: What is the service temperature range for A387 Gr. 22?
A: ASTM A387 Gr. 22 is an alloy steel primarily designed for elevated temperatures. Its typical service temperature ranges from 316°C to 593°C (600°F to 1100°F), with specific capabilities depending on the class level and exact composition.
Q: What is the difference between A387 Gr. 22 Class 1 and Class 2?
A: While ASTM A387 Grade 22 Class 1 and Class 2 share the exact same chemical composition (2.25% Chromium and 1.00% Molybdenum), the primary difference lies in their mechanical properties and heat treatment. Class 2 features significantly higher tensile and yield strength, whereas Class 1 offers better formability and weldability.
Q: What is the impact toughness of A387 Gr. 22?
A: The impact toughness of ASTM A387 Grade 22 depends heavily on its specific heat treatment (Class 1 vs. Class 2) and testing temperature. Generally, for pressure vessel and boiler applications, the Charpy V-notch (CVN) impact energy for this 2.25% Cr - 1% Mo alloy steel is typically ≥ 27 J at room temperature and ≥ 20 J at 0°C.
Q: Is A387 Gr. 22 easy to weld?
A: A387 Gr. 22 is moderately difficult to weld. Because it is a chromium-molybdenum (chrome-moly) alloy steel, it is highly susceptible to hydrogen-induced cracking and temper embrittlement. Successful welding requires strict preheating (usually 150°C to 250°C) and mandatory Post-Weld Heat Treatment (PWHT) to relieve residual stresses and restore ductility.
