Cryogenic pipelines are concentrated in distillation systems and liquid storage backup systems. According to the standard, the lowest operating temperature of austenitic stainless steel 06Cr19Ni10 can reach -255℃, and it has good strength, plasticity, toughness and welding performance at low temperatures, and the production and installation process is mature. 06Cr19Ni10 can be used as the material for cryogenic pipelines. Seamless pipes should comply with GB/T 14976-2012 "Stainless steel seamless steel pipes for fluid transportation" standard, and welded steel pipes should comply with GB/T 12771-2019 "Stainless steel welded steel pipes for fluid transportation" standard or HG/T 20537.3-1992 "Technical requirements for austenitic stainless steel welded steel pipes for chemical equipment" and HG/T 20537.4-1992 "Technical requirements for austenitic stainless steel large-diameter welded steel pipes for chemical equipment". When seamless steel pipes are used at -196℃ and above, low-temperature impact tests can be exempted. The welded joints of welded steel pipes shall be subjected to low temperature impact tests according to GB/T 20801.2-2020.
For liquid oxygen pipelines, according to the Catalogue of Hazardous Chemicals, liquid oxygen is an oxidizing medium. According to the pressure pipeline classification in Article 4 of GB/T 20801.1-2020 "Pressure Pipeline Specification Industrial Pipeline Part 1: General Provisions", liquid oxygen pipelines with a nominal diameter greater than or equal to 50 and a design pressure less than 10MPa are judged as GC2[3]. This is different from the pressure pipeline level of high-pressure oxygen. Since oxygen is a Class B flammable gas, the pressure level of oxygen pipelines with a design pressure greater than or equal to 4MPa is judged as GC1.
Therefore, the cryogenic pipeline material should be reasonably selected according to the pressure pipeline level.
