What material are the disks and seats of valves in high temperature steam systems surfaced with?

The disks and seats of valves in high-temperature steam systems are surfaced with Stellite due to its exceptional properties that make it ideal for such applications. Stellite is an alloy that contains cobalt, chromium, and tungsten, which grants it excellent wear resistance, high-temperature strength, and corrosion resistance.

In high-temperature environments, such as those found in steam systems, materials must withstand not only extreme heat but also the erosive and corrosive nature of steam. Stellite’s ability to maintain its hardness and structural integrity at elevated temperatures makes it a preferred choice for valve components that are subjected to high pressures and temperatures.

Other materials like brass, stainless steel, and bronze do not possess the same level of durability or resistance to the specific conditions found in high temperature steam systems. Brass, while having good machinability, is susceptible to corrosion under steam conditions. Stainless steel can handle heat but may not have the same wear resistance as Stellite in such applications. Bronze is also used, but it doesn't match the high-temperature performance and wear characteristics needed in these critical components. Therefore, the decision to use Stellite for valve disks and seats in high-temperature steam systems is based on the need for reliability and long service life in demanding conditions.