According to the flange connection form, the butterfly valve body is mainly divided into: wafer type A, wafer type LT, single flange, double flange, U type flange.
Wafer type A is non-threaded hole connection, LT type 24" above large specifications usually use better strength U-type valve body to do threaded connection, the end of the pipeline needs to use LT type.
According to the sealing structure, the butterfly valve body can be divided into rubber vulcanized body (non-replaceable seat body), split valve body (generally with corrosion-resistant seat), and replaceable seat body (with hard back seat and soft seat).
The body materials of our commonly used in concentric butterfly valves are mainly: cast iron, ductile iron, cast steel body, cast stainless steel body, cast copper body, cast aluminum body and cast super duplex steel body.
Cast iron: The most common material inside the butterfly valve, mainly used in the water system, easy to be corroded, short service life, cheap.
Cast iron: Cast iron is suitable for nominal pressure PN ≤ 1.0MPa, temperature -10 ℃ ~ 200 ℃ of water, steam, air, gas and oil and other media. Gray cast iron commonly used standards and grades are: GB/T 12226, HT200, HT250, HT300, HT350.
Ductile iron: In the butterfly valve performance is comparable to carbon steel a material, generally used in the water system pipeline, but also at present the water system on the use of a very wide range of materials.
Ductile iron: Suitable for PN ≤ 2.5MPa, temperature -30 ~ 350 ℃ water, steam, air and oil and other media. Commonly used standards and grades are: GB/T12227:2005 QT400-15, QT450-10, QT500-7; EN1563 EN-GJS-400-15,ASTM A536,65 45-12,ASTM A395,65 45 12.
Carbon steel: Can also be used in the water system, carbon steel butterfly valve has a high temperature and pressure resistance, general hard seal butterfly valve more with carbon steel material.
Carbon steel: Suitable for nominal pressure PN ≤ 3.2MPa, temperature -30 ~ 425 ℃ water, steam, air, hydrogen, ammonia, nitrogen and petroleum products and other medium. Commonly used grades and standards are ASTM A216/216M:2018WCA, WCB, ZG25 and high quality steel 20, 25, 30 and low alloy structural steel 16MN.
Stainless steel: Stainless steel butterfly valves have very good rust and corrosion resistance, and are also mostly used in pipelines that need corrosion and rust resistance, and the cost is relatively high. Applicable to nominal pressure PN ≤ 6.4.0MPa, temperature range: -268 ° C to +425 ° C, usually used in water, seawater, chemical industry, oil and gas, medicine, food medium. Common standards and grades: ASTM A351/351M:2018, SUS304,304, SUS316, 316
Copper alloy: Copper alloy butterfly valve is suitable for PN ≤ 2.5MPa water, seawater, oxygen, air, oil and other medium, as well as steam media at a temperature of -40 ~ 250 ℃, commonly used grades for ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (brass), QAZ19-2, QA19-4 (aluminum bronze). Common standards and grades: ASTM B148:2014, UNS C95400, UNS C95500, UNS C95800; ASTM B150 C6300.