ASTM A645 Low Alloy Steel Capillary

ASTM A645 Low Alloy Steel Capillary Product Information -:- For detailed product information, please contact sales. -: ASTM A645 Low Alloy Steel Capillary Synonyms -:- For detailed product information, please contact sales. -:

ASTM A645 Low Alloy Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: ASTM A645 Special Pressure Vessel Steel Plate** **ASTM A645** is a specialized low-alloy steel specification established by the American Society for Testing and Materials (ASTM). It is designed specifically for the fabrication of welded pressure vessels intended for service at extremely low (cryogenic) temperatures, particularly down to **-320°F (-196°C)**, which is the boiling point of liquid nitrogen. The primary distinguishing feature of A645 is its **5% nickel (Ni) alloy content**. Nickel significantly enhances the low-temperature toughness of steel by refining its microstructure and raising the ductile-to-brittle transition temperature, ensuring the material retains ductility and resistance to crack propagation in cryogenic environments. This steel is supplied in the **normalized heat treatment condition** to achieve a fine-grained microstructure, which is essential for its exceptional toughness properties. --- ### **1. International Standard & Key Specifications** * **Primary Standard:** **ASTM A645 / A645M** - Standard Specification for Pressure Vessel Plates, 5% Nickel Alloy Steel, Specially Heat Treated. * **Common Referenced Standards:** * **ASTM A20/A20M:** Standard general requirements for steel plates for pressure vessels. * **ASME Boiler and Pressure Vessel Code, Section II, Part A:** The material is often approved for use under the ASME code as **SA-645**. * **Related Material:** It is the U.S. equivalent to other international 5% nickel steels, such as **EN 10028-4: P9 (1.5680)**. --- ### **2. Chemical Composition (Weight %, Ladle Analysis)** The composition is carefully controlled to ensure weldability and consistent low-temperature performance. | Element | Composition (%) | | :--- | :--- | | Carbon (C) | 0.13 max | | Manganese (Mn) | 0.50 - 0.80 | | Phosphorus (P) | 0.025 max | | Sulfur (S) | 0.025 max | | Silicon (Si) | 0.15 - 0.40 | | Nickel (Ni) | 4.75 - 5.25 | | Molybdenum (Mo) | 0.20 - 0.35 | | Vanadium (V) | 0.04 max | | Columbium (Cb) / Niobium (Nb) | 0.05 max | *Note: The low carbon and controlled alloy content are critical for good weldability and toughness.* --- ### **3. Mechanical & Physical Properties** Typical properties for normalized plates are as follows: **A. Mechanical Properties (Room Temperature):** * **Yield Strength (0.2% Offset):** ≥ 55 ksi (380 MPa) min. * **Tensile Strength:** 75 - 95 ksi (515 - 655 MPa). * **Elongation in 2-in (50 mm):** ≥ 20% min. **B. Key Requirement - Impact Toughness (Charpy V-Notch):** This is the most critical property for A645. Tests are conducted at **-320°F (-196°C)**. * **Minimum Average Value:** 25 ft-lbf (34 J) for three specimens. * **Minimum Individual Value:** 20 ft-lbf (27 J) for a single specimen. * *The steel must demonstrate exceptional energy absorption at cryogenic temperatures to prevent brittle fracture.* **C. Typical Physical Properties:** * **Density:** ~0.284 lb/in³ (7,860 kg/m³). * **Modulus of Elasticity:** ~29 x 10⁶ psi (200 GPa) at room temperature. * **Coefficient of Thermal Expansion:** ~6.5 x 10⁻⁶/°F (11.7 x 10⁻⁶/°C) between 70-212°F. * **Thermal Conductivity:** Lower than carbon steel, approximately 26 W/m·K at room temperature. --- ### **4. Product Forms & Availability** * **Form:** Supplied primarily as **rolled and normalized plates**. * **Thickness Range:** Typically available from about 0.25 inches (6 mm) up to several inches thick, as required for pressure vessel fabrication. * **Condition:** Normalized (heated to above the critical temperature and air-cooled). --- ### **5. Key Applications** ASTM A645 is exclusively used in critical cryogenic pressure vessel applications, including: * **Liquefied Natural Gas (LNG) Storage & Transport:** * Inner containment tanks for onshore LNG storage tanks. * Primary and secondary barriers in membrane-type LNG carrier ships (though 9% Ni steel and stainless steels are also common). * **Cryogenic Processing Vessels:** * Storage tanks for liquid nitrogen (LIN), liquid oxygen (LOX), liquid argon (LAR), and liquid ethylene. * Vessels for air separation units (ASU). * Equipment in petrochemical and gas processing plants handling very low-temperature fluids. * **Specialized Aerospace & Research Applications:** Containment vessels for cryogenic fluids in testing and propulsion systems. --- ### **6. Advantages & Considerations** **Advantages:** * **Superior Cryogenic Toughness:** Proven reliability at temperatures as low as -196°C. * **Good Strength:** Provides a high strength-to-weight ratio compared to austenitic stainless steels (like 304L). * **Cost-Effective:** More economical than 9% nickel steel or aluminum alloys for many large-scale cryogenic tank applications. **Considerations (Fabrication & Handling):** * **Welding:** Requires strict welding procedures. Preheating and the use of suitable low-temperature nickel-alloy welding consumables (e.g., AWS A5.23/5.23M F9PZ-ENiCrMo-6) are mandatory to maintain toughness in the weld and Heat-Affected Zone (HAZ). * **Heat Treatment:** Post-weld heat treatment (PWHT) may be required for specific applications to relieve stresses, but it must be carefully controlled to avoid compromising the base metal's properties. * **Quality Control:** Stringent testing, including impact testing of production test plates and often the weld procedure qualification plates, is essential. --- ### **Summary** **ASTM A645 (5% Nickel Steel)** is a premium, low-alloy steel engineered for exceptional performance in the most demanding cryogenic environments. Its balanced chemistry and normalized microstructure provide an optimal combination of strength, fabrication characteristics, and, most importantly, guaranteed fracture toughness at temperatures down to -196°C. It remains a material of choice for the safe and economical construction of large-scale pressure vessels in the global LNG and industrial gas industries. -:- For detailed product information, please contact sales. -: ASTM A645 Low Alloy Steel Specification Dimensions Size： Diameter 20-1000 mm Length <4507 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 A645 Low Alloy Steel Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A645 Low Alloy Steel Capillary -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A645 Low Alloy Steel Capillary -:- For detailed product information, please contact sales. -:

Packing of ASTM A645 Low Alloy Steel Capillary -:- 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 Capillary 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 978 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