Key considerations for selecting materials for low-temperature pressure vessels

Low-temperature pressure vessels primarily face brittle fracture as a failure mode. Steel materials tend to become more brittle and lose toughness at low temperatures, which necessitates stricter requirements compared to materials used in non-cryogenic vessels. The selection of materials for low-temperature applications must adhere to stringent regulations regarding the steelmaking process, chemical composition, and heat treatment conditions. Additionally, the chosen materials must meet impact toughness requirements at low temperatures.

For steel materials used in applications where the design temperature is below -20°C and the minimum tensile strength is less than 540 MPa, the phosphorus (P) content must not exceed 0.025%, and the sulfur (S) content must not exceed 0.012%. If the minimum tensile strength is greater than 540 MPa, the phosphorus content must be ≤0.02%, and the sulfur content must be ≤0.01%. Furthermore, pressure-bearing components of low-temperature vessels, as well as non-pressure components directly welded to them, must be made of steel with excellent weldability.

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Classification of Low-Temperature Steel Based on Design Temperature

1.Design Temperature: -20°C to -40°C

For pressure vessels operating at temperatures between -20°C and -40°C, materials equivalent to ASTM A516 Grade 70 is commonly used. These steels are suitable for outdoor applications such as air storage tanks and nitrogen storage tanks, which are exposed to environmental temperature fluctuations.

2.Design Temperature: -40°C to -196°C

For applications where the design temperature ranges from -40°C to -196°C, nickel-based low-temperature steels are the preferred choice.

ASTM A537 (equivalent to 09MnNiDR in Chinese standards) is suitable for applications at -70°C, such as liquid ammonia storage tanks.

ASTM A203 Grade E (equivalent to 08Ni3DR) is used for pressure vessels operating at -100°C.

ASTM A553 Type I (equivalent to 06Ni9DR) is used for liquid oxygen and liquid nitrogen storage tanks, which operate at -196°C.

3.Design Temperature: Below -196°C to -273°C

For ultra-low-temperature applications below -196°C, austenitic stainless steels are typically used due to their superior toughness at cryogenic temperatures.

ASTM A240 Type 304 (S30408): A commonly used austenitic stainless steel suitable for extreme low-temperature pressure vessels, such as those used in liquefied natural gas (LNG) storage and cryogenic applications.

The selection of materials for low-temperature pressure vessels is crucial to ensure structural integrity and safety. Proper material choice depends on factors such as design temperature, impact toughness requirements, weldability, and chemical composition. By following stringent standards such as ASTM A516, A537, A203, A553, and A240, manufacturers can ensure the reliability and longevity of pressure vessels operating under extreme cold conditions.

At Haihao Group, we specialize in manufacturing high-quality low-temperature pressure vessel components. Our expertise in material selection and advanced manufacturing processes ensures that our products meet the highest international standards. If you require customized low-temperature pressure vessel solutions, feel free to contact us for professional support.Email:sales@haihaogroup.com