Valves for low-temperature systems?

Refer to JB/T5300-91, \"Materials for Major Parts of Low-Temperature Steel Valves\", which specifies requirements for the valve body, valve cover, valve seat, operating elements, rocker, valve stem, sealing surfaces of the valve seat and operating elements, packing, gaskets, etc. The relevant content in the \"Handbook for Design of Petrochemical Pipeline Installation\" can also be consulted. For low-temperature valves used to transport media at temperatures below a certain level or at temperatures equal to or above -100 degrees, the selection of materials for their major parts should comply with the table below:

Materials for Major Parts of Low-Temperature Valves
Part Name | Material (for temperatures ≥ -100 degrees) | Material (for temperatures < -100 degrees)
---|---|---
Valve Body, Valve Cover, Valve Disc | 3.5Ni, ZG0Cr18Ni9, ZG1Cr18Ni9, ZG0Cr18Ni9Ti, ZG1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti |
Valve Stem, Valve Seat | 1Cr17Ni2, 1Cr18Ni9, 0Cr19Ni9, 1Cr18Ni9Ti |
Sealing Surfaces (same) | F2201F, F2202F, F2203F, F2204F, F2205F |
Packing | Polytetrafluoroethylene, Flexible graphite, PTFE-coated asbestos rope |
Middle Flange Gaskets | Pure copper, Pure aluminum, Asbestos rubber sheet coated with wax, Polytetraflouroethylene, Stainless steel wound gaskets

Based on the operating temperature you specified, austenitic stainless steels (316, 304SS) can be used for the material. The valve types that can be employed include disc valves, ball valves, and gate valves; however, the valve stem needs to be extended, with the extension length depending on the temperature of the medium. In addition, the material must undergo Charpy impact tests. The main design standard is BS6364, while the domestic standard in China is JBT7749