Gate Valve Material Selection Guide: Choosing the Right Materials for Your Application
Material selection for gate valves directly impacts corrosion resistance, temperature tolerance, and service life. Understanding the properties of different materials ensures reliable performance across various operating conditions.The main gate valves product names of China gate Valve Network include:GB Bellows Wedge Gate Valve,High Temperature & pressure Power Station Gate Valve,Inside Screw Non-rising Stem Wedge Gate Valve,Insulation Jacket Gate Valve,Lined Gate Valve,MZ44W Rising Stem Gas Quick Open&close ParallelMZ48W Manual Non-rising Stem City Gas Quick Gate Valve,Manual Knife-shaped Gate Valve,Manual Slurry ValveManual Wedge Copper Gate Valve
Body and Bonnet Materials
Gray cast iron (HT200, HT250) suits non-corrosive media such as water and air at temperatures up to 200°C with pressure ratings ≤PN16. It offers low cost but limited strength.
Ductile iron (QT400-15, QT450-10) provides higher strength and excellent toughness, making it ideal for water, oil, and steam services up to PN25 and temperatures ranging from -20°C to 350°C. It is widely used in water supply systems.
Carbon steel (WCB) is the most common industrial valve material, suitable for oil, water, and steam in non-corrosive services at pressures up to PN320 and temperatures from -29°C to 425°C. It combines strength, toughness, and good machinability.
Alloy steel (WC6, WC9) contains chromium and molybdenum, enabling reliable performance in high-temperature steam systems up to 570°C, commonly found in power plants.
Stainless steel (CF8, CF8M) delivers exceptional corrosion resistance, making it the preferred choice for aggressive media such as acids and alkalis. It operates across a wide temperature range from -196°C to 600°C, serving chemical and pharmaceutical industries.
Copper alloys are often specified for seawater and marine applications due to their excellent resistance to saltwater corrosion.
Seat Materials
Copper alloys work well for low-pressure ambient conditions. Hardfacing with Stellite or similar wear-resistant alloys provides durability under high temperature, high pressure, and abrasive services. EPDM and NBR rubber deliver superior sealing performance for resilient-seated gate valves in water systems. PTFE offers excellent chemical resistance for corrosive media but has a lower temperature limit of approximately 200°C.
Stem Materials
For water, steam, and oil services, martensitic stainless steel (2Cr13, 1Cr13) is commonly used. Austenitic stainless steel (304, 316) provides corrosion resistance for aggressive environments. 17-4PH precipitation-hardening stainless steel delivers high strength for high-pressure applications.
Anti-Corrosion Coating
Water supply gate valves require electrostatic spray application of non-toxic epoxy coating with a minimum thickness of 0.3 mm. This coating prevents rust, eliminates galvanic corrosion, and must pass hygiene certification.
| Medium | Body Material | Seat Material | Temperature Range |
|---|---|---|---|
| Water | Gray/Ductile Iron | Rubber/Copper | ≤200°C |
| Oil/Steam | Carbon Steel WCB | Hardfacing | -29°C to 425°C |
| High-Temp Steam | Alloy Steel WC9 | Hardfacing | ≤570°C |
| Corrosive Media | Stainless Steel CF8M | PTFE/Hardfacing | -196°C to 600°C |
Proper material selection based on service conditions ensures reliable gate valve operation and extended service life. Always reference applicable standards such as GB/T 12232, GB/T 12234, and consult qualified manufacturers for specific applications.
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