ASTM A542 Low Alloy Steel Flange, Grade B, Class 2

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 A542 Low Alloy Steel Flange, Grade B, Class 2 Product Information -:- For detailed product information, please contact sales. -: ASTM A542 Low Alloy Steel Flange, Grade B, Class 2 Synonyms -:- For detailed product information, please contact sales. -:

ASTM A542 Low Alloy Steel, Grade B, Class 2 Product Information -:- For detailed product information, please contact sales. -: ### **ASTM A542 Grade B Class 2: High-Temperature 2.25Cr-1Mo Steel Plate** #### **1. Overview** ASTM A542 Grade B Class 2 is a **medium-strength quenched and tempered 2.25% chromium-1% molybdenum alloy steel plate** that provides an optimal balance of high-temperature strength, creep resistance, and hydrogen attack resistance. This intermediate class within the Grade B classification offers enhanced mechanical properties compared to Class 1, making it suitable for heavy-wall pressure vessels in refinery hydroprocessing units and high-temperature power generation equipment where both strength and long-term reliability are critical. #### **2. Chemical Composition** The chemical composition maintains precise control for consistent high-temperature performance: | Element | Composition (%) | |---------|-----------------| | Carbon (C) | 0.15 max | | Manganese (Mn) | 0.30 - 0.60 | | Phosphorus (P) | 0.025 max | | Sulfur (S) | 0.025 max | | Silicon (Si) | 0.15 - 0.40 | | Chromium (Cr) | 2.00 - 2.50 | | Molybdenum (Mo) | 0.90 - 1.10 | **Optimized Composition Features:** - **Enhanced Chromium (2.00-2.50%)**: Provides superior oxidation and sulfidation resistance - **Higher Molybdenum (0.90-1.10%)**: Improves high-temperature strength and carbide stability - **Controlled Carbon (0.15% max)**: Ensures good weldability and toughness - **Balanced Manganese Range**: Optimizes hardenability without compromising fabricability #### **3. Physical & Mechanical Properties** **Mechanical Properties (Quenched & Tempered Condition):** | Property | Requirement | |----------|-------------| | **Tensile Strength** | 85 - 105 ksi (585 - 725 MPa) | | **Yield Strength** | 55 ksi min (380 MPa min) | | **Elongation in 2 inches** | 17% min | | **Reduction of Area** | 40% min | | **Charpy V-Notch Impact** | 35 ft-lb min at -50°F (-46°C) | **Elevated Temperature Performance:** - **Enhanced Creep Strength**: Superior long-term performance at temperatures up to 1200°F (650°C) - **Excellent Hydrogen Resistance**: Meets API 941 Nelson Curve requirements for hydrogen service - **Oxidation Resistance**: Maintains integrity in high-temperature oxidizing environments - **Thermal Fatigue Resistance**: Good performance under thermal cycling conditions **Physical Properties (Typical):** - **Density**: 0.282 lb/in³ (7,810 kg/m³) - **Modulus of Elasticity**: 29,300 ksi (202 GPa) at 70°F (21°C) - **Thermal Expansion Coefficient**: 6.3 × 10⁻⁶/°F (11.3 × 10⁻⁶/°C) from 70-1000°F - **Thermal Conductivity**: 24.5 W/m·K at 212°F (100°C) #### **4. Product Applications** Grade B Class 2 is specified for intermediate high-temperature, high-pressure applications: **Petroleum Refining:** - Heavy-wall hydrocracking reactors - High-pressure hydrotreating vessels - Hydrogen compression equipment - Refinery conversion unit reactors **Power Generation:** - Intermediate pressure steam drums - High-temperature boiler components - Power plant piping systems - Heat recovery steam generators **Chemical Processing:** - High-temperature chemical reactors - Synthesis gas converters - High-pressure process vessels - Petrochemical reaction systems #### **5. International Standards & Equivalents** | Region/Country | Standard | Equivalent Grade | Notes | |----------------|----------|------------------|-------| | **International** | **ISO 9328-2** | 10CrMo9-10 | Similar chromium-molybdenum composition | | **Europe** | **EN 10028-2** | 10CrMo9-10 | Comparable elevated temperature properties | | **Japan** | **JIS G4109** | SCMV 4 | Chromium-molybdenum pressure vessel steel | | **Germany** | **DIN 17155** | 10CrMo910 | Well-established equivalent grade | **Grade B Class Comparison:** | Parameter | Class 1 | Class 2 | Class 3 | |-----------|---------|---------|---------| | **Yield Strength Minimum** | 45 ksi | 55 ksi | 65 ksi | | **Tensile Strength Range** | 75-95 ksi | 85-105 ksi | 95-115 ksi | | **Application Focus** | Standard Strength | Intermediate Strength | High Strength | #### **6. Fabrication & Quality Assurance** **Welding and Fabrication Requirements:** - **Pre-heat requirement**: 350-450°F (175-230°C) depending on thickness - **Post-weld heat treatment**: Mandatory at 1275-1375°F (690-745°C) - **Welding consumables**: Low-hydrogen electrodes with matching composition - **Interpass temperature control**: 400-600°F (200-315°C) maximum **Heat Treatment Protocol:** - **Austenitizing temperature**: 1650-1750°F (900-955°C) - **Quenching medium**: Water or accelerated cooling required - **Tempering range**: 1275-1425°F (690-775°C) - **Microstructural requirements**: Fully tempered bainitic structure mandatory **Quality Control and Testing:** - **Impact testing**: At specified temperature for each heat treatment charge - **Tension tests**: From representative locations of each plate - **Hardness verification**: Typically 200-240 HBW - **Ultrasonic examination**: Per supplementary requirements when specified --- **Technical Advantages:** - **Enhanced strength** at intermediate temperature ranges - **Superior resistance to hydrogen attack** in refinery service - **Excellent thermal stability** during long-term exposure - **Good fabricability** for heavy-wall construction **Design and Application Considerations:** - **ASME Section VIII Division 1** design rules applicable - **Creep life assessment** recommended for temperatures above 800°F (425°C) - **Hydrogen service evaluation** per API 941 requirements - **Environmental degradation** factors must be considered **Service Limitations and Guidelines:** - **Maximum design temperature**: 1200°F (650°C) for continuous service - **Minimum design temperature**: -50°F (-46°C) based on impact requirements - **Hydrogen service limitations**: Per API 941 Nelson Curve requirements - **Oxidation limits**: Based on service environment and temperature **Disclaimer:** This technical information is for reference purposes. For high-temperature pressure vessel applications involving hydrogen service, consult the latest ASTM A542 specification and applicable ASME Code requirements. All design, material selection, and fabrication activities must be approved by qualified engineers and comply with API 941 recommendations and relevant regulatory standards. -:- For detailed product information, please contact sales. -: ASTM A542 Low Alloy Steel, Grade B, Class 2 Specification Dimensions Size： Diameter 20-1000 mm Length <4443 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 A542 Low Alloy Steel, Grade B, Class 2 Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A542 Low Alloy Steel Flange, Grade B, Class 2 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A542 Low Alloy Steel Flange, Grade B, Class 2 -:- For detailed product information, please contact sales. -:

Packing of ASTM A542 Low Alloy Steel Flange, Grade B, 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 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 914 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