The valve body is a main part of the valve; there are different mechanical manufacturing methods according to the pressure level. For example: casting, forging, etc.
Valve bodies of medium and low pressure specifications are usually produced by casting process.
The valve body of medium and high pressure specification is produced by forging process.
It can effectively withstand medium pressure after forming a seal together with the valve core and valve seat sealing ring.
The definition of “valve” is a device used to control the direction, pressure, and flow of fluid in a fluid system. A valve is a device that allows the medium (liquid, gas, powder) in the piping and equipment to flow or stop, and can control its flow
The material of the valve body is selected according to different process media.
Common materials are: cast iron, cast steel, stainless steel, carbon steel, plastic, copper, etc. 
1. grey cast iron:
Grey cast iron valves are used in various fields of industry because of their low price and wide application range. They are usually used in the case of water, steam, oil and gas as the medium, and are widely used in chemical industry, printing and dyeing, oil chemical, textile and many other industrial products that have little or no impact on iron pollution. It is suitable for low pressure valves with working temperature between -15～200℃ and nominal pressure PN≤1.6MPa.
2. Ductile cast iron
Ductile cast iron is a kind of cast iron. In this cast iron, the flake graphite in gray cast iron is replaced by clump or nodular graphite. The change in the internal structure of this metal makes its mechanical properties better than ordinary gray cast iron, and does not damage other properties. Therefore, valves made of ductile iron have higher pressures than those made of gray cast iron. It is suitable for medium and low pressure valves with working temperature between -30～350℃ and nominal pressure PN≤4.0MPa. Applicable media are water, sea water, steam, air, gas, oil, etc.
3. Carbon steel:
The initial development of cast steel was to meet the production needs that exceeded the capabilities of cast iron valves and bronze valves. However, because the carbon steel valve has good overall performance and high resistance to stress caused by thermal expansion, impact load and pipeline deformation, it has expanded its use range, usually including the working conditions of cast iron valves and bronze valves. . Suitable for medium and high pressure valves with working temperature between –29～425℃. Among them, the temperature of 16Mn and 30Mn is between -40～400℃, and they are often used to replace ASTM A105. The applicable medium is saturated steam and superheated steam. High and low temperature oil, liquefied gas, compressed air, water, natural gas, etc.