ASTM A387 Alloy Steel Flange, Grade 21, Class 1

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Flange, Grade 21, Class 1 Product Information -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Flange, Grade 21, Class 1 Synonyms -:- For detailed product information, please contact sales. -:

ASTM A387 Alloy Steel, Grade 21, Class 1 Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: ASTM A387 Grade 21 Class 1 Steel** **ASTM A387 Grade 21 Class 1** is a chromium-molybdenum alloy steel plate designed for high-temperature pressure vessel applications, offering enhanced corrosion resistance and elevated temperature strength. This specification covers plates in the annealed or normalized and tempered condition, suitable for welded pressure vessels operating in severe service environments. --- #### **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 1** - Annealed or 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: | 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:** - **Higher Chromium Content**: 2.75-3.25% for superior oxidation and corrosion resistance - **Enhanced Molybdenum**: 0.90-1.10% for improved creep strength - **Controlled Carbon**: 0.05-0.15% for optimal weldability and toughness - **Lower Manganese**: 0.30-0.60% for better high-temperature properties --- #### **3. Physical & Mechanical Properties** **Mechanical Properties (Class 1 condition):** | Property | Value | |---|---| | **Tensile Strength** | 515-690 MPa (75-100 ksi) | | **Yield Strength (min.)** | 310 MPa (45 ksi) | | **Elongation in 2" (min.)** | 18% | | **Elongation in 8" (min.)** | 20% | **Elevated Temperature Properties:** - **Maximum Service Temperature**: Up to 650°C (1200°F) - **Creep Strength**: Excellent resistance to creep deformation - **Oxidation Resistance**: Superior performance in oxidizing atmospheres - **Hydrogen Resistance**: Good resistance to hydrogen attack **Physical Properties:** - **Density**: 7.87 g/cm³ (0.284 lb/in³) - **Modulus of Elasticity**: 205 GPa (29,700 ksi) - **Thermal Conductivity**: 42.5 W/m·K - **Coefficient of Thermal Expansion**: 11.5 × 10⁻⁶/°C - **Specific Heat Capacity**: 460 J/kg·K --- #### **4. Product Applications** **High-Temperature Pressure Vessels:** - Hydrocracking reactors - Hydrogen processing vessels - High-temperature reactors - Severe service pressure vessels **Power Generation:** - High-pressure steam components - Advanced boiler systems - High-temperature heat exchangers - Power plant reformer tubes **Petrochemical Industry:** - Catalytic reforming units - Hydrogenation reactors - High-temperature process vessels - Refinery hydroprocessing equipment **Special Applications:** - Synthetic fuel processing equipment - High-temperature chemical reactors - Advanced energy systems - High-pressure high-temperature (HPHT) equipment --- #### **5. Fabrication Characteristics** **Welding Performance:** - **Fair Weldability**: Requires careful procedure control - **Preheat Requirements**: 200-250°C (400-480°F) minimum - **Post-Weld Heat Treatment**: Mandatory at 690-730°C (1275-1350°F) - **Recommended Processes**: GTAW, SMAW (low-hydrogen) - **Filler Metals**: E9015-B3, ER90S-B3 or equivalent **Forming & Machining:** - **Moderate Formability**: Hot forming required for complex shapes - **Machinability**: Fair to poor (approximately 45% of B1112 steel) - **Cutting Methods**: Plasma and waterjet cutting recommended - **Hot Working Temperature**: 1050-1200°C (1920-2190°F) **Heat Treatment:** - Supplied in annealed or normalized and tempered condition - Normalizing temperature: 925-955°C (1700-1750°F) - Tempering temperature: 675-705°C (1250-1300°F) - Annealing temperature: 845-875°C (1550-1600°F) **Quality Assurance:** - **Comprehensive Testing**: Full mechanical and chemical analysis - **Impact Testing**: Required for pressure vessel applications - **Hardness Testing**: Mandatory quality control - **Non-Destructive Testing**: UT, RT, MT as specified --- ### **Technical Summary** ASTM A387 Grade 21 Class 1 represents an advanced chromium-molybdenum alloy steel specifically designed for severe high-temperature and high-pressure applications. The 3% chromium content provides significantly improved oxidation and corrosion resistance compared to lower alloy grades, while the 1% molybdenum content ensures excellent creep strength and high-temperature stability. This grade is particularly suitable for applications involving hydrogen service at elevated temperatures and pressures, where resistance to hydrogen attack is crucial. The enhanced alloy composition makes it ideal for hydrocracking reactors, hydrogen processing equipment, and other severe service applications in the petrochemical and refining industries. While requiring more sophisticated fabrication techniques and stringent quality controls, Grade 21 Class 1 delivers reliable performance in the most demanding service conditions. The material's proven track record in high-temperature hydrogen service and its ability to withstand aggressive corrosive environments have established it as a preferred choice for critical pressure vessel applications where conventional chromium-molybdenum steels would be inadequate. The balanced combination of high-temperature strength, corrosion resistance, and hydrogen service capability makes ASTM A387 Grade 21 Class 1 an essential material for advanced energy systems, petrochemical processing, and high-temperature pressure vessel applications where performance reliability and long-term service integrity are paramount considerations. -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 1 Specification Dimensions Size： Diameter 20-1000 mm Length <4366 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 1 Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A387 Alloy Steel Flange, Grade 21, Class 1 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A387 Alloy Steel Flange, Grade 21, Class 1 -:- For detailed product information, please contact sales. -:

Packing of ASTM A387 Alloy Steel Flange, Grade 21, Class 1 -:- 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 Flange 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 837 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