ASTM A387 Alloy Steel Foil/Strip, Grade 21, Class 2

ASTM A387 Alloy Steel Foil, Grade 21, Class 2 Product Information -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Foil, Grade 21, Class 2 Synonyms -:- For detailed product information, please contact sales. -:

ASTM A387 Alloy Steel, Grade 21, Class 2 Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: ASTM A387 Grade 21 Class 2 Steel** **ASTM A387 Grade 21 Class 2** is a premium chromium-molybdenum alloy steel plate supplied in the normalized and tempered condition, offering enhanced mechanical properties for the most demanding high-temperature pressure vessel applications. This class provides superior strength and microstructural stability for severe service conditions. --- #### **1. International Standards & Classification** **Primary Standard:** **ASTM A387/A387M** - "Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum" **Grade Classification:** - **Grade 21** - 3.0% Chromium - 1.0% Molybdenum alloy steel - **Class 2** - Normalized and tempered condition **International Equivalents:** - **EN 10028-2**: 16CrMo5-5 - **JIS G4109**: SCMV 6 - **GB/T 3077**: 20Cr3MoWVA - **ISO 9328-2**: 16CrMo5-5 --- #### **2. Chemical Composition** The chemical composition requirements for ASTM A387 Grade 21 Class 2: | Element | Composition (Maximum %) | |---|---| | Carbon (C) | 0.05-0.15 | | Manganese (Mn) | 0.30-0.60 | | Phosphorus (P) | 0.035 | | Sulfur (S) | 0.035 | | Silicon (Si) | 0.50 | | Chromium (Cr) | 2.75-3.25 | | Molybdenum (Mo) | 0.90-1.10 | **Key Composition Features:** - **Enhanced Chromium**: 2.75-3.25% for superior high-temperature corrosion resistance - **Optimized Molybdenum**: 0.90-1.10% for maximum creep strength - **Precise Carbon Control**: 0.05-0.15% for optimal strength-toughness balance - **Restricted Manganese**: 0.30-0.60% for improved high-temperature stability --- #### **3. Physical & Mechanical Properties** **Mechanical Properties (Class 2 condition):** | Property | Value | |---|---| | **Tensile Strength** | 585-760 MPa (85-110 ksi) | | **Yield Strength (min.)** | 380 MPa (55 ksi) | | **Elongation in 2" (min.)** | 16% | | **Elongation in 8" (min.)** | 18% | **Enhanced Elevated Temperature Properties:** - **Maximum Service Temperature**: Up to 650°C (1200°F) - **Creep Rupture Strength**: Superior long-term performance - **Oxidation Resistance**: Excellent in high-temperature environments - **Hydrogen Attack Resistance**: Suitable for high-pressure hydrogen service **Physical Properties:** - **Density**: 7.87 g/cm³ (0.284 lb/in³) - **Modulus of Elasticity**: 205 GPa (29,700 ksi) - **Thermal Conductivity**: 41.5 W/m·K - **Coefficient of Thermal Expansion**: 11.4 × 10⁻⁶/°C - **Specific Heat Capacity**: 455 J/kg·K --- #### **4. Product Applications** **Critical High-Temperature Service:** - Hydrocracking reactor vessels - High-pressure hydrogen vessels - Catalytic reforming reactors - Severe service pressure containers **Advanced Power Generation:** - Ultra-supercritical boiler components - High-temperature steam piping - Advanced heat exchanger systems - High-pressure turbine components **Petrochemical Processing:** - Hydrodesulfurization reactors - High-pressure synthesis vessels - Severe service process equipment - Refinery hydroprocessing units **Specialized Applications:** - Nuclear power plant components - Advanced energy systems - High-pressure high-temperature (HPHT) equipment - Special chemical processing vessels --- #### **5. Fabrication Characteristics** **Welding Performance:** - **Controlled Weldability**: Requires qualified welding procedures - **Preheat Requirements**: 200-300°C (400-575°F) mandatory - **Post-Weld Heat Treatment**: Essential at 690-730°C (1275-1350°F) - **Recommended Processes**: GTAW, SMAW (strict low-hydrogen control) - **Filler Metals**: E9015-B3, ER90S-B3 or higher grade equivalents **Forming & Machining:** - **Limited Formability**: Hot forming essential for all significant deformation - **Machinability**: Poor (approximately 40% of B1112 steel) - **Cutting Methods**: Waterjet and laser cutting preferred - **Hot Working Range**: 1050-1150°C (1920-2100°F) **Heat Treatment:** - Supplied in normalized and tempered condition - Normalizing temperature: 925-955°C (1700-1750°F) - Tempering temperature: 675-705°C (1250-1300°F) - Microstructure: Fine bainitic structure with carbides **Quality Assurance:** - **Enhanced Testing Protocol**: Multiple test locations required - **Comprehensive Impact Testing**: Stringent toughness requirements - **Advanced NDT**: Full ultrasonic examination typically required - **Metallurgical Verification**: Microstructure and grain size evaluation --- ### **Technical Summary** ASTM A387 Grade 21 Class 2 represents the premium grade in chromium-molybdenum alloy steels, offering the highest strength level combined with exceptional high-temperature performance. The normalized and tempered heat treatment produces an optimal microstructure that provides outstanding creep strength, thermal stability, and resistance to high-temperature corrosion. With a minimum yield strength of 55 ksi (380 MPa), Class 2 offers approximately 20% higher strength than Class 1, enabling more efficient designs for high-pressure applications while maintaining excellent elevated temperature capabilities. The 3% chromium content provides superior resistance to oxidation and sulfidation, making it particularly suitable for refining and petrochemical applications. This grade demonstrates exceptional performance in hydrogen service at elevated temperatures, where its composition provides inherent resistance to hydrogen attack and high-temperature hydrogen damage. The material's proven reliability in hydrocracking reactors, hydrogen processing vessels, and other severe service applications has established it as the material of choice for the most demanding pressure vessel applications. While requiring the most stringent fabrication controls and comprehensive quality assurance measures, Grade 21 Class 2 delivers unmatched performance in critical high-temperature, high-pressure service conditions. Its ability to maintain mechanical integrity under extreme operating conditions makes it indispensable for advanced energy systems, petrochemical processing, and other applications where safety, reliability, and long-term performance are paramount. -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 2 Specification Dimensions Size： Diameter 20-1000 mm Length <4367 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 2 Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A387 Alloy Steel Foil, Grade 21, Class 2 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A387 Alloy Steel Foil, Grade 21, Class 2 -:- For detailed product information, please contact sales. -:

Packing of ASTM A387 Alloy Steel Foil/Strip, Grade 21, Class 2 -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Foil/Strip drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 838 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition