ASTM A387 Grade 22 Class 1 is a chromium-molybdenum (Cr-Mo) alloy steel plate used for welded boilers and pressure vessels in elevated temperature service, offering good strength and corrosion resistance, with Class 1 representing the standard tensile strength level for such applications. It contains approximately 2.25% chromium and 1.00% molybdenum, providing enhanced high-temperature strength and improved corrosion resistance compared to carbon steels, suitable for oil & gas, petrochemical, and power generation industries.
Specifications for ASTM A387 Grade 22 Alloy Steel Plates
Chromium & Molybdenum content (according to the ASME specification)
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| A387 Grade 22 | 2.25% | 1.00% |
Chemical Requirements for ASTM A387 Grade 22 Alloy Steel Plates
| Element | Chemical Composition (%) | |
| A387 Grade 22 | ||
| Carbon: | Heat Analysis: | 0.05 - 0.15 |
| Product Analysis: | 0.04 - 0.15 | |
| Manganese: | Heat Analysis: | 0.30 - 0.60 |
| Product Analysis: | 0.25 - 0.66 | |
| Phosphorus: | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Sulphur (max): | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Silicon: | Heat Analysis: | 0.50 max |
| Product Analysis: | 0.50 max | |
| Chromium: | Heat Analysis: | 2.00 - 2.50 |
| Product Analysis: | 1.88 - 2.62 | |
| Molybdenum: | Heat Analysis: | 0.90 - 1.10 |
| Product Analysis: | 0.85 - 1.15 |
Equivalents for ASTM A387 Grade 22 Alloy Steel Plates
| BS | EN | ASTM/ASME | DIN |
| 622-515B | 10 CRMO910 | A387-22-1 | 10 CRMO910 |
applications
1. Petrochemical & Chemical Processing
Used extensively in refineries and chemical plants for equipment that must withstand extreme thermal and chemical stress:
High-Pressure Reactors: Ideal for hydrogenation units and catalytic crackers that operate under high hydrogen partial pressures, as the molybdenum content enhances resistance to high-temperature hydrogen attack (HTHA).
Separators & Storage Vessels: Handles corrosive media such as sour gas (H2S) and high-pressure steam. Its chromium content (typically 2.00–2.50%) provides a protective layer against oxidation and chemical attack.
Safety & Reliability: The alloy's resistance to stress corrosion cracking and pitting ensures the long-term safety of fluid transport systems.
2. Power Generation
A staple material for the power industry, particularly in fossil fuel and nuclear power stations:
Boiler Drums & Superheater Tubes: Capable of handling high-pressure steam and continuous exposure to temperatures up to 600°C.
Furnace Components: Its structural durability allows it to withstand thermal cycling (repeated heating and cooling) without significant creep deformation or scaling.
System Integrity: Used in pressure components to reduce maintenance costs and prevent downtime in demanding energy generation environments.
3. Oil & Gas Facilities
Applied in both offshore and onshore facilities for critical fluid handling:
High-Pressure Piping: Used for pipelines and complex piping systems that transport volatile or corrosive substances under extreme pressure.
Processing Equipment: Utilized for high-performance machinery and specialized containers where structural stability is required in harsh, high-temperature environments.
4. Industrial Heat Exchangers
Crucial for heat transfer systems where dimensional stability is a priority:
Thermal Stability: Operates effectively at temperatures reaching 600°C (1112°F) while maintaining its shape and mechanical strength over thousands of service hours.
Oxidation Resistance: High heat tolerance prevents the formation of scale on the surface, ensuring efficient heat transfer and preventing surface degradation.
Fabrication: Class 1's superior ductility and weldability make it ideal for the complex geometries required in custom heat exchanger and condenser designs.
If you want to learn more about (ASTM A387 Grade 22 Class 1 )GNEE's products, you can send an email to beam@gneesteelgroup.com. We are more than happy to assist you.
What is the difference between ASTM a387 GRADE 22 CLASS 1and Class 2?
ASTM A387 Grade 22 Class 1 and Class 2 are chromium-molybdenum alloy steel plates for pressure vessels with identical chemical composition; their key difference lies in mechanical properties-Class 2 has higher tensile and yield strength than Class 1, which results from different heat treatment (normalizing+tempering for Class 1, quenching+tempering for Class 2). Consequently, Class 1 offers better weldability and formability for low-stress pressure vessel components, while Class 2 is suited for high-stress, high-temperature and high-pressure applications despite stricter processing requirements.
What is ASTM A387?
A high quality chrome molybdenum alloy steel plate intended specifically for use in weldable carbon steel pressure vessels at elevated temperatures. Added molybdenum gives the material greater temperature tensile strength and the chromium provides improved corrosion resistance.