classify
Cast steel gate valves: according to materials, there are carbon steel gate valves, stainless steel gate valves, low alloy steel gate valves (high temperature resistant chromium molybdenum steel belongs to this category) and low temperature steel gate valves.
Under all kinds of cast steel gate valves, there are various specific steel grades, which are commonly used:
1. The brands of carbon steel gate valve castings are: WCA, WCB, WCC, LCB, etc. Applicable temperature -46 ~425 degrees.
2. Casting brands of stainless steel gate valves: 30 1 stainless steel, CF8 stainless steel (corresponding to forged 304 stainless steel), CF8M stainless steel (corresponding to forged 3 16 stainless steel), etc. Applicable temperature-198 ~8 16.
3. Low alloy steel is divided into high-temperature alloy steel and high-strength low alloy steel, among which high-temperature alloy steel is often called Cr-Mo steel.
The casting brands of Cr-Mo steel gate valves are ZG 1Cr5Mo, ZG 15Cr 1MoV, ZG20CrMoV, WC6, WC9, C 12A, etc. The applicable temperature is 550 ~750℃.
The applicable temperature of each specific brand material is different, depending on the actual working conditions.
Press the valve stem to move up and down.
According to whether the valve stem is ascending or descending, gate valves can be divided into open-stem gate valves and concealed-stem gate valves. When the valve stem rotates, it lifts the open-stem gate valve; The valve stem can only rotate, but it can't be lifted.
The gate of exposed stem gate valve moves linearly with the valve stem, which is called lifting stem gate valve (also known as exposed stem gate valve).
merits and demerits
1, advantages of cast steel gate valve: small fluid resistance, small sealing surface brush and medium erosion. Opening and closing is labor-saving. The flow direction of the medium is not limited, which does not interfere with the flow and does not reduce the pressure. Simple structure, short structural length, good manufacturing manufacturability, many optional materials capable of resisting high temperature and high pressure, and wide application range.
2. Disadvantages of cast steel gate valves: erosion wear is easy to occur between sealing surfaces, and maintenance is difficult. The overall size is large, it needs a certain space to open, and the opening and closing time is long.
The above is the classification, advantages and disadvantages of cast steel gate valves introduced by Bian Xiao today. Cast steel gate valves made of different materials are suitable for different places. Cast steel gate valves have many advantages, so they are widely used. However, because their maintenance will be more troublesome, it is necessary to consider whether the selection of cast steel gate valves meets the requirements in combination with their advantages and disadvantages and the place of use. The role of cast steel gate valve is not only to intercept, but also to control the liquid flow, so cast steel gate valve will be used in many places.
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