What are the commonly used materials of Chinese valves?
1.Gray cast iron: Gray cast iron is suitable for water, steam, air, gas, oil and other media with nominal pressure PN≤ 1.0mpa and temperature ranging from -10℃ to 200℃.Common grades of gray cast iron are: HT200, HT250, HT300 and HT350.
2.Malleable cast iron: suitable for water, steam, air and oil media with nominal pressure PN≤ 2.5mpa and temperature -30 ~ 300℃, commonly used brands: KTH300-06, KTH330-08, KTH350-10.
3.Ductile iron: applicable to water, steam, air and oil with PN≤ 4.0mpa and temperature between -30 ~ 350℃.Common grades are: QT400-15, QT450-10, QT500-7.
In view of the current level of domestic technology, different plants, users are often not easy to inspect. According to experience, it is recommended that PN≤ 2.5mpa, the valve should be made of steel.
4.Acid-resistant high silicon ductile iron: suitable for corrosive medium with nominal pressure PN≤0.25MPa and temperature below 120℃.
5.Carbon steel: suitable for medium such as water, steam, air, hydrogen, ammonia, nitrogen and petroleum products with nominal pressure PN≤32.0MPa and temperature -30 ~ 425℃.Common grades are WC1, WCB, ZG25, high quality steel 20, 25, 30 and low alloy structural steel 16Mn.
6.Copper alloy: suitable for medium such as water, seawater, oxygen, air and oil with PN≤ 2.5mpa, as well as medium such as steam with temperature of -40 ~ 250℃. Commonly used grades are ZGnSn10Zn2(tin bronze), H62, HPB59-1 (brass), QAZ19-2, QA19-4(aluminum bronze).
7.Vii. High temperature copper: applicable to steam and petroleum products with nominal pressure PN≤17.0MPA and temperature ≤570℃.Commonly used brand ZGCr5Mo, 1 cr5m0. ZG20CrMoV, ZG15Gr1Mo1V, 12 crmov WC6, WC9, etc. Specific selection must be in accordance with the valve pressure and temperature specifications.