ASTM A736 Low Alloy Steel Flange, Grade A, 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 A736 Low Alloy Steel Flange, Grade A, Class 1 Product Information -:- For detailed product information, please contact sales. -: ASTM A736 Low Alloy Steel Flange, Grade A, Class 1 Synonyms -:- For detailed product information, please contact sales. -:

ASTM A736 Low Alloy Steel, Grade A, Class 1 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: ASTM A736/A736M Grade A, Class 1 Low-Alloy Steel for Pressure Vessels** **ASTM A736/A736M Grade A, Class 1** is a **precipitation-strengthened, high-strength low-alloy (HSLA) steel** specifically engineered for **welded pressure vessels requiring a superior combination of strength, toughness, and weldability**. This grade achieves its mechanical properties primarily through **precipitation hardening with microalloying elements like columbium (niobium) and vanadium**, typically supplied in the **normalized and tempered or quenched and tempered condition**. Its defining characteristic is an **exceptionally high yield strength (minimum 80 ksi / 550 MPa)** coupled with good notch toughness, making it an advanced material for weight-efficient designs in demanding industrial applications. --- ## **International Standard & Key Specifications** * **Primary Standard:** **ASTM A736/A736M** - Standard Specification for Pressure Vessel Plates, Low-Carbon Age-Hardening Nickel-Copper-Chromium-Molybdenum-Columbium Alloy Steel. * **"Age-Hardening" Distinction:** This specification covers steels that gain strength from a controlled precipitation process, often involving a two-stage heat treatment (solution treating + aging or tempering). * **ASME Code Equivalent:** **SA-736/SA-736M** in ASME Boiler and Pressure Vessel Code, Section II, Part A. This is the mandatory specification for ASME-stamped pressure equipment. * **Governing Standard:** **ASTM A20/A20M** - Standard Specification for General Requirements for Steel Plates for Pressure Vessels. * **Key Feature:** Offers significantly higher strength-to-weight ratios than conventional carbon-manganese pressure vessel steels (e.g., ASTM A516). --- ## **Chemical Composition (Weight %, max unless range is specified)** The chemistry is precisely balanced to facilitate precipitation hardening while maintaining excellent weldability and toughness. The alloy system is complex, leveraging multiple elements for synergistic strengthening. | Element | Composition (%) | Role in Performance | | :--- | :--- | :--- | | **Carbon (C)** | 0.07 max | **Extremely low.** Maximizes weldability and toughness, shifting the strengthening mechanism entirely to precipitation. | | **Manganese (Mn)** | 0.40 - 0.70 | Provides solid solution strengthening and aids hardenability. | | **Phosphorus (P)** | 0.025 max | Impurity, kept at minimal levels. | | **Sulfur (S)** | 0.025 max | Impurity, tightly controlled. | | **Silicon (Si)** | 0.15 - 0.50 | Deoxidizer. | | **Nickel (Ni)** | 0.70 - 1.00 | Enhances toughness, strength, and hardenability. | | **Chromium (Cr)** | 0.40 - 0.65 | Improves hardenability and provides moderate corrosion/oxidation resistance. | | **Molybdenum (Mo)** | 0.20 - 0.30 | Enhances hardenability, strength at elevated temperature, and resistance to temper embrittlement. | | **Copper (Cu)** | 1.00 - 1.30 | **Primary precipitation-hardening element.** Forms fine Cu-rich precipitates during aging/tempering to provide major strength increase. | | **Columbium (Cb/Nb)** | 0.02 - 0.10 | **Critical microalloy.** Forms fine Nb(CN) precipitates that inhibit grain growth (during normalizing) and contribute significantly to precipitation strengthening. | | **Vanadium (V)** | 0.03 - 0.08 | Complementary microalloy for precipitation strengthening and grain refinement. | | **Aluminum (Al)** | 0.06 max | Grain refining deoxidizer. | --- ## **Typical Physical & Mechanical Properties (Grade A, Class 1)** Class 1 typically indicates a specific combination of heat treatment and toughness requirements. Properties are for normalized/quenched and tempered plates. | Property | Value / Description | | :--- | :--- | | **Tensile Strength** | 620 - 795 MPa (90,000 - 115,000 psi) | | **Yield Strength (min)** | **550 MPa (80,000 psi)** | | **Elongation in 2-in (50 mm) (min)** | 18% | | **Modulus of Elasticity** | ~200 GPa (29 x 10⁶ psi) | | **Density** | ~7.85 g/cm³ (0.284 lb/in³) | | **Charpy V-Notch Impact Toughness** | **Test Temperature:** **-60°F (-50°C)**. **Minimum Avg. for 3 Specimens:** **25 ft·lbf (34 J)**. | | **Brinell Hardness (typical)** | 210 - 250 HBW | | **Key Advantage:** Very high yield-to-tensile strength ratio, enabling more efficient (thinner) pressure vessel designs. | --- ## **Product Applications** ASTM A736 Grade A, Class 1 is used in advanced pressure vessel designs where minimizing weight and material usage is critical without compromising integrity, especially for transportable vessels or large structures. **Primary Industries and Equipment:** 1. **Transportable Pressure Vessels:** * **High-Pressure Gas Transport Tubes/Trailers** for hydrogen, natural gas (CNG), and industrial gases. * **Railcar Tanks** for specialized chemical and gas transport. 2. **Oil, Gas & Petrochemical:** * **High-Pressure Separators** and **Scrubbers** in offshore platforms and onshore plants, where weight savings are crucial. * **Reactor Vessels** for processes requiring high strength-to-weight ratios. * **Heat Exchanger Shells** for high-design-pressure services. 3. **Power Generation:** * **Feedwater Heaters** and **Moisture Separator Reheaters (MSRs)** in high-pressure power plants. * **Hydrogen Coolers** in turbine generators. 4. **Aerospace & Defense:** * **Pressure Vessels** for rocket fuel systems, portable gas storage, and other weight-sensitive containment applications. --- ## **Advantages and Critical Fabrication Considerations** * **Advantages:** * **Exceptional Strength-to-Weight Ratio:** The 80 ksi minimum yield strength allows for significantly lighter vessel designs compared to conventional 50-70 ksi steels. * **Excellent Toughness:** Maintains good notch toughness at low temperatures despite its high strength. * **Good Weldability (for its strength class):** The ultra-low carbon content results in a very low carbon equivalent, reducing susceptibility to hydrogen-induced cracking (HIC) and cold cracking. * **Critical Fabrication & Welding Considerations:** * **Heat Treatment Sensitivity:** The properties are highly dependent on the final heat treatment (tempering/aging cycle). Fabrication processes must not expose the material to temperatures that would over-age or overtemper it, causing strength loss. * **Welding Procedure Qualification:** **Mandatory use of low-hydrogen processes.** Welding Procedure Specifications (WPS) must be rigorously qualified, often requiring impact testing of weld and HAZ. Matching strength filler metals are essential. * **Preheat and Interpass Control:** Required, typically in the range of **200°F - 300°F (95°C - 150°C)**, to prevent cracking. * **Post-Weld Heat Treatment (PWHT):** Often required for pressure vessel fabrication. The PWHT temperature and time must be carefully controlled to match or complement the base metal's aging treatment without causing over-aging. * **Thermal Cutting:** Preheating is recommended. Machined edges are preferred for critical applications to avoid any heat-affected zone effects from cutting. **In summary, ASTM A736 Grade A, Class 1 is a sophisticated, precipitation-hardened low-alloy steel that delivers an outstanding 80 ksi minimum yield strength with good toughness. It is a premium material selected for advanced engineering applications where maximizing pressure capacity while minimizing structural weight is a primary design driver, particularly in transportable equipment and weight-constrained installations.** -:- For detailed product information, please contact sales. -: ASTM A736 Low Alloy Steel, Grade A, Class 1 Specification Dimensions Size： Diameter 20-1000 mm Length <4527 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 A736 Low Alloy Steel, Grade A, Class 1 Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A736 Low Alloy Steel Flange, Grade A, Class 1 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A736 Low Alloy Steel Flange, Grade A, Class 1 -:- For detailed product information, please contact sales. -:

Packing of ASTM A736 Low Alloy Steel Flange, Grade A, 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 998 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