LNG, air separation and cryogenic equipment demand high low-temperature toughness:

1) Grade: austenitic 304L/316L retain good toughness at cryogenic temperatures (−162°C LNG, −196°C liquid nitrogen) and are the usual choice. Ferritic and martensitic grades are prone to brittle fracture at low temperature and are unsuitable. 2) Impact testing: perform low-temperature Charpy impact tests (e.g. −196°C) per the standard to confirm toughness. 3) Welding: control heat input and interpass temperature, use matching consumables (e.g. 308L/316L), inspect per code. 4) Design: avoid stress concentration and cold-brittle configurations. 5) Applications: LNG tank inner shells, cryogenic piping, air separation equipment.

Purchasing reminder: require low-temperature impact reports, material certificates and welding procedure qualification; protect against mechanical damage during transport and installation.

Note: "stainless" does not automatically mean "suitable for low temperature" — check the grade and impact data.