When selecting the valve material of the gate valve, the material should be determined according to the actual conditions of working conditions such as temperature, pressure & medium. The material of ZECO gate valve includes, but is not limited to stainless steel, carbon steel, forged and cryogenic.
Water, oil, natural gas, steam, and other non-corrosive media the most commonly used material of valve body, valve bonnet, and the wedge is A216 WCB, and after NACE MR-01-75 or NACE MR-01-03 treatment, A216 WCB material is also often used in the condition of slight corrosion. One thing to note, however, is that the temperature range of A216 WCB is -29℃ to 425℃.
Gate Valve Parts
- The valve body is the primary part of the valve which holds everything together. Mostly it is connected to piping through flange and gasket. It is the pressure boundary of the valve.
- The valve bonnet is the second boundary of pressure. It is connected with a valve body with bolts or flange.
- The valve trim collectively stems, seat, and the disk is known as valve trim. Valve performance is dependent on seat and disk arrangement.
- The seat and disk are the most important part of the gate valve. It contains a gate-type disk and seat which fits the disk tightly.
- The stem connects the actuator and disk in the gate valve. It opens and closes the disk and seat arrangement. Two types of the stem are available one is rising which rises when we open the valve and the other is non-rising which has no vertical motion.
- Valve Actuator is a manual wheel which operates stem and disk arrangement.
How to Select Valve Materials
The challenge in making a material choice is actually verifying that the chosen material best fits the application. This involves taking into account working conditions and flow media properties.
Most important concerning the working conditions is to know the pressure and temperature ratings and for working media is to take in consideration corrosive and erosive properties. Additionally, it might be needed to consider thermal and physical shock, line stress and fire hazards.
Broadly speaking when considering temperature limitations of different groups of materials Table 1. should be used as general reference for material selection.
|Very High||2000||Refractory Metals, Ceramics|
|Low||-250||Low Alloy Steels|
|Very Low(Cryogenic)||-450||Bronze, Austenitic Ductile Iron|
|Austenitic Stainless Steels|
In some cases a compromise must be reached in selecting a material. Some service conditions require use of exotic alloys and metals to withstand particular corrosive properties of the flowing fluid. These materials are much more expensive than common metals, so economy may also be a factor in material selection. Table 2 shows ASTM materials widely used for valve bodies and bonnets.
|ANSI Class||Material||ASTM Specification|
|125||Cast Iron||A216 Cl. B|
|150||Bronze||B 62 / B 148|
|150||Carbon Steel||A216 GR. WCB|
|200||Bronze||B 61 / B 148|
|250||Cast Iron||A216 Cl. B|
|300||Carbon Steel||A216 GR. WCB|
|600||Carbon Steel||A216 GR. WCB|
The trim typically includes a disk, seat, stem, and sleeves needed to guide the stem. Valve trim materials in relation to temperature limits should be selected in according to Table 3.
|304 SST, S30400, CF8||Uncoated Plugs and Seats||-450||-268||600||316|
|316 SST, S31600, CF8M||Uncoated Plugs and Seats||-450||-268||600||316|
|317 SST, S31700, CG8M||Uncoated Plugs and Seats||-450||-268||600||316|
|416 SST, S41600, 38 HRC min||Cages, Plugs and Seats||-20||-29||800||427|
|CA6NM, 32 HRC min||Cages, Plugs and Seats||-20||-29||900||482|
|Nitronic 50, S20910 High Strength Condition||Shaft, Stem and Pins||-325||-198||1100||593|
|440 SST, S44004||Bushings, Plugs and Seats||-20||-29||800||427|
|17-4PH, S17400, CB7Cu-1, H1075 Condition||Cages, Plugs and Seats||-80||-62||800||427|
|Alloy 6, R3006, CoCr-A||Plugs and Seats||-325||-198||1500||816|
|Electroless Nickel Coating||Trim Coating||-325||-198||750||400|
|Hard Chromium Plating||Trim Coating||-325||-198||600||316|
|Hard Chromium Plating on V-Balls||Trim Coating||-325||-198||800||427|
|Hard Chromium Coating||Trim Coating||-325||-198||1100||593|
|Monel K500, N05500||Uncoated Plugs and Seats||-325||-198||800||427|
|Monel K400, N04400||Uncoated Plugs and Seats||-325||-198||800||427|
|Hastelloy B2, N10665, N7M||Uncoated Plugs and Seats||-325||-198||800||427|
|Hastelloy C276, N10276, CW2M||Uncoated Plugs and Seats||-325||-198||800||427|
|Titanium Grades 2, 3, 4, C2, C3, C4||Uncoated Plugs and Seats||-75||-59||600||316|
|Nickel, N02200, CZ100||Uncoated Plugs and Seats||-325||-198||600||316|
|Alloy 20, N08020, CN7M||Uncoated Plugs and Seats||-325||-198||600||316|
|NBR, Nitrile Rubber||Seats||-20||-29||200||93|
|HDPE, High Density Polyethylene||Seats||-65||-54||185||85|
Gate Valve for Sale List by Material
Cast Steel Gate ValveZECO cast steel gate valve is in controlled under the quality assurance system of production and manufacturing, has met all the international industry standards and user requirements documented procedures./ GET VALVE PRICE >
High Pressure Gate ValveWhen the pressure is low, the flange thickness is small, the cost increase is not much, the heat stress generated when heating and cooling is small, rely on bolt tightening force and gasket easy to achieve sealing./ GET VALVE PRICE >
Material Choices of Gate Valve
Like high-temperature conditions, the medium is high-temperature steam or hot air conditions, usually, the choice of materials for high-temperature-resistant materials such as A217 WC6, A217 WC9, the temperature range of A217 WC6 & A217 WC9 is -29℃ to 593℃.
A352 LCB, A352 LCC is usually used for a low-temperature application, usually, the medium is of low-temperature but over -46℃ or through conduit gate valve is installed outdoor in area of a cold environment. But these materials can not be used for high-temperature over 345℃.
A351 CF8, A351 CF8M, A351 CF3, A351 CF3M, these austenitic stainless steel are anti-rust and anti-corrosion, suitable for the medium of various kinds of acid. A351 CF8, A351 CF8M, A351 CF3 & A351 CF3M can be used in most low temperature conditions, but it needs cryogenic treatment. It can also be used in most high-temperature conditions, but there are corresponding standards for carbon content.
Aluminum-bronze like B148 C95800, B62 C83600, B283 C61300, and other Al-bronze are perfectly suitable for seawater application.
Duplex Steel A890 4A, A890 5A, SAF2205, S31803 and super duplex steel A890 6A, SAF2507, S32750 have similar application range of Al-Bronze, they have good resistance to chloride corrosion, so they are widely used for seawater application and produced water application.