Low-temperature pressure vessels operate under extreme conditions where conventional fasteners may become brittle and lose their mechanical strength. Proper fastener selection and design are essential to maintain structural integrity, safety, and long-term reliability in cryogenic environments.

Fasteners Bolts and nuts

Material Selection for Low-Temperature Fasteners

Flanged connections in low-temperature pressure vessels require stud fasteners that can withstand cryogenic temperatures without becoming brittle. The selection of materials is based on the operating temperature range:

For design temperatures between -40°C and -70°C, studs should be made of 35CrMoA steel.

For design temperatures between -70°C and -100°C, studs should be made of 30CrMoA steel.

For temperatures lower than -100°C, austenitic stainless steel studs should be used to ensure excellent toughness and corrosion resistance.

Additional Requirements for Low-Temperature Fasteners

Sulfur(S)and phosphorus (P) content must be strictly controlled to improve low-temperature toughness.

Fasteners should undergo low-temperature impact testing to ensure they maintain mechanical properties in extreme conditions.

Stud design:

The unthreaded shank diameter should not exceed 0.95 times the thread root diameter to prevent stress concentration.

Fully threaded elastic studs can be used to accommodate thermal expansion and contraction, improving overall system reliability.

Proper fastener selection is critical for low-temperature pressure vessels, ensuring mechanical stability and safety in extreme conditions. Using materials with high impact toughness and excellent low-temperature performance prevents brittle failure.

At Haihao Group, we provide customized cryogenic fasteners that meet international standards, ensuring durability and reliability in demanding applications. Contact us for expert solutions in low-temperature engineering.Email:sales@haihaogroup.com