ASTM A736 Low Alloy Steel, Grade A, Class 1

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

Packing of ASTM A736 Low Alloy Steel, 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 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