The body, bonnet and gate (disc) are one of the main parts of the valve and are directly subjected to media pressure. The material used must conform to the Pressure and Temperature Class of the valve.

Commonly used materials are the following:
I. Grey cast iron:

Grey cast iron is suitable for medium such as water, steam, air, gas and oil with nominal pressure PN < 1.0MPa and temperature -10 ~200 ~C.Common grades of gray cast iron are HT200, HT250, HT300 and HT350.
2. Malleable iron:

It is suitable for water, steam, air and oil media with nominal pressure PN < 2.5MPa and temperature of -30-300 C. Common brands are: KTH300-06, KTH330-08 and KTH350- 10.
III. Ductile iron:

It is suitable for medium such as water, steam, air and oil with PN < 4.0MPa and temperature of -30~350 C.Commonly used brands are: QT400-15, QT450-10 and QT500-7. 

In view of the current domestic process level, the plants are uneven and the users are often not easy to inspect.Based on experience, it is recommended that PN < 2.5MPa or Steel Valves be used for safety. 

IV. Acid-resistant High Silicon Ductile iron:

suitable for corrosive media with nominal pressure PN < 0.25MPa and temperature below 120 C. 

V. 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 ~C.Commonly used grades are WC1, WCB, ZG25 and high quality steel 20, 25, 30 and low alloy structural steel 16Mn.

VI. Copper Alloys:

It is suitable for water, seawater, oxygen, air, oil and other media with PN < 2.5MPa, as well as steam media with temperature -40~250 C. The commonly used brands are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (brass), QAZ19-2, QA19-4 (aluminum bronze).It is suitable for water, seawater, oxygen, air, oil and other media with PN < 2.5MPa, as well as steam media with temperature - 40~250 C. The commonly used brands are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (brass), QAZ19-2, QA19-4 (aluminum bronze).

VII. High Temperature Copper:

It is suitable for steam and petroleum products with nominal pressure PN < 17.0MPA and temperature < 570C.Commonly used brands are ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9, etc.Specific selection must be in accordance with the valve pressure and temperature specifications. 

VIII. Low Temperature Steel

8. Low temperature steel is suitable for medium such as nominal pressure PN < 6.4Mpa, temperature (>-196 C) ethylene, propylene, liquid natural gas, liquid nitrogen, etc. Commonly used brands) are ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.

IX. Stainless acid-resistant steel

It is suitable for medium such as nitric acid and acetic acid with nominal pressure PN < 6.4Mpa, temperature < 200 C. Commonly used brands are ZG0Cr18Ni9Ti, ZG0Cr18Ni10 <nitric acid resistance>, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti &lt