I. 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.
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 ~