As one of the valve fittings, the valve stem is not only a moving part, but also a bearing part during the use of the valve. At the same time, it is subject to impact and corrosion by the media and also creates friction with the filler. Therefore, when selecting the valve stem material, it must be ensured that it has sufficient strength, good impact toughness, scratch resistance and corrosion resistance at the specified temperature.
Moreover, this valve fitting is a consumable part, so it is necessary to consider the machinability and heat treatment properties of the material when selecting. Commonly used materials for valve stems are copper alloy, carbon steel, alloy steel, stainless steel and bearing chrome steel. The copper alloy fittings are mostly used for low pressure valves with a nominal pressure of less than or equal to 1.6 MPa and a temperature of less than or equal to 200 °C.
Carbon steel valve fittings are mostly used for low and medium pressure valves in water, steam and other media. Alloy steel valve fittings are suitable for water, steam, petroleum and other media with a nominal pressure of 32 MPa or less and a temperature of 450 °C or less. Stainless steel and bearing chrome steel valve fittings have the characteristics of no corrosion, no seizure with the valve stem.http://www.pump-casting.com/