Metal Seated Gate Valve

Metal seated gate valve, also known as metal-to-metal hard sealed gate valve, is a heavy-duty shut-off equipment designed for high temperature, high pressure, oil, gas, steam and corrosive industrial pipeline systems. Different from resilient seated gate valves relying on rubber sealing, its sealing surfaces are made of metal materials, enabling stable performance under extreme temperature and pressure conditions. Widely used in petrochemical industry, power plants, metallurgy, heating networks, natural gas transmission and refinery projects.

The core sealing pair consists of precisely machined metal contact surfaces. Common sealing surface treatment includes hardfacing with Stellite alloy, chromium spraying and nitriding treatment, which greatly improves wear resistance, scratch resistance and high-temperature resistance. The metal sealing structure can operate continuously within a wide temperature range, from low-temperature medium up to 550°C, while rubber soft sealing valves cannot withstand high temperature environments. Most metal seated gate valves adopt wedge disc structure, including single rigid wedge, flexible wedge and double wedge types. Flexible wedge can absorb thermal deformation effectively to guarantee reliable sealing under temperature fluctuation.

Multiple material options satisfy diversified working conditions. Valve body materials cover cast carbon steel WCB, alloy steel WC6, stainless steel CF8/CF8M and ductile iron. End connections include flanged RF, butt weld and threaded ends. International standards such as API 600, ASME B16.34, DIN 3356 and GB/T12234 can be implemented according to customer requirements. Pressure classes range from PN16 up to PN160, Class150 to Class2500 to match various heavy industrial pipelines.

Two mainstream stem designs are available: outside screw & yoke rising stem (OS&Y) and non-rising stem (NRS). The OS&Y structure displays opening position visually and is convenient for field monitoring. The stem adopts stainless steel or alloy steel, equipped with graphite and PTFE composite packing suitable for high temperature. Blowout-proof stem structure prevents accidental medium leakage under abnormal pressure, significantly improving operational safety. Driving modes include manual handwheel, bevel gear, electric and pneumatic actuator to realize automatic pipeline control.

It must be noted that metal seated gate valve is only suitable for fully open or fully closed cut-off operation. Throttling is prohibited. Long-term partial opening will cause rapid abrasion and scouring damage on metal sealing surfaces, leading to leakage and shortened service life. Compared with soft seal valves, metal seated gate valves require higher machining precision and larger operating torque.

All valves undergo strict shell hydrostatic test and seat tightness test according to ISO 5208 and API 598 before delivery. Every sealing surface is inspected to ensure matching precision. Thanks to excellent high temperature resistance, pressure resistance and aging resistance, metal seated gate valve becomes irreplaceable shut-off equipment for high-temperature steam, fuel oil, natural gas and chemical medium pipelines. Our factory can provide customized trim material, fire-safe structure and anti-static design for flammable medium working conditions to meet strict requirements of international EPC engineering projects.