How to choose a cryogenic valve?
Earlier we have shared a selection table for the metal material of the regulating valve , which briefly describes how to choose according to the chemical properties of the gas or liquid contacted by the valve body. In the actual operation of the valve, the operating temperature of the regulating valve is one of the important considerations in the design and selection of the regulating valve. In order to regulate the suitable working temperature of the valve body material, the suitable working temperature and related temperature of the valve main materials used in China's petrochemical, chemical, fertilizer, electric power and metallurgical industries are related to the material properties of various types of valve steel and alloy grades. Clear requirements are required for the design, manufacture and inspection of valve products. In addition, from the aspects of technical management, production management and material procurement, the comprehensive performance should be selected for each type of steel. It is not advisable to use too many steel grades and alloy grades to prevent confusion. Today, let us first understand the choice of valve materials under low temperature conditions.
Cryogenic valve material
The main materials suitable for low temperature valves (-100 ~ -30 ° C) are low temperature austenitic stainless steel and ferrite and martensitic steel for low temperature bearing parts. Austenitic stainless steels for low temperature have ASTM A351 CF8M, CF3M, CF8 and CF3, ASTM A182 F316, F316L, F304 and F304L, ASTM A433 316, 316L, 304, 304L and CF8D. Ferritic and martensitic steels for low temperature pressure parts are ASTM 352 LCA (-32 ° C), LCB, LCC (-46 ° C), LC1 (-59 ° C), LC 2, LC 211 (-73 ° C) and LC 3 (-100 °C). The primary price of materials in the ASTMA 352 standard is lower, but the chemical composition of the smelting must have reliable and demanding factory internal control standards. The heat treatment process is complicated and requires multiple times of quenching and tempering treatment to meet the requirements of the standard requirements for low temperature impact toughness and long production cycle. When the low temperature impact toughness does not meet the standard requirements, it is not allowed to use the low temperature steel.
Therefore, it is only used when the production batch is large and can be used for furnace smelting, and austenitic stainless steel is generally used.
Ultra-low temperature valve material
Ultra-low temperature valve (-254 (liquid hydrogen) ~ -101 ° C (ethylene)) main material must use a face-centered cubic lattice of austenitic stainless steel, copper alloy or aluminum alloy, its low temperature mechanical properties after heat treatment, especially low temperature impact Resilience must meet the requirements of the standard. The following austenitic stainless steels can be used to make ultra-low temperature valves. ASTM A351 CF8M, CF3M, CF8 and CF3, ASTM A182 F316, F316L, F304 and F304L, ASTM A433 316, 316L, 304, 304L and CF8D (designed by Lanzhou High Pressure Valve Factory, factory standard code GFQ81-93). The valve body, bonnet, gate or disc of the ultra-low temperature valve must be cryogenically treated in liquid nitrogen (-196 ° C) before finishing.
ZXSD pneumatic film low temperature angle control valve produced by Yuanfeng is a regulating valve used in low temperature and deep cooling applications. The long-neck bonnet is insulated and equipped with a multi-spring actuator, which has the advantages of compact overall structure, light weight and good stability.
The main parts are as follows:
Body: LF4 valve stem: 304/316/316L
Valve cover: 0Cr18Ni9 Bellows: 304/316/316L
Spool, seat: 304/316/316L/17-4PH pad: copper, 0Cr18Ni9
ZXSD pneumatic film low temperature angle regulating valve is widely used in low temperature and deep cooling applications such as metallurgy, air separation, oxygen production, petroleum and chemical industry. It is especially suitable for precise control of process parameters of low temperature gases, liquids (such as liquid oxygen, liquid nitrogen, liquid argon, etc.) at a given value.
Fuyang Yuanfeng Valve Industry Co., Ltd. is a professional manufacturer of regulating valves. Its main products include various types of pneumatic regulating valves, electric regulating valves, self-operated regulating valves, high performance butterfly valves, nitrogen sealing valves and various special valves.