In ball valves, the seat material is typically produced from Teflon material. Teflon provides high performance in many different applications from water to sulfuric acid, from paint to demineralized water. However, this material, which has a very low abrasion resistance, is also not suitable for working at high temperatures (>200 ºC). For this reason, when high temperatures pass through the valve with solid particles, such as in a Gold Mine process, the Bearings must be manufactured from metal materials with high abrasion and temperature resistance. The issue to be considered in metal seated ball valves is tightness. Typical Metal seated Ball valves usually seal to ISO 5208 Rate D or ANSI CLASS IV. Of course, although valves with Rate A or CLASS VI sealing class can be produced with the developing technology, the initial investment cost of these valves is quite high. Since zero impermeability is provided by Graphite added to the bearing component, the lifetime of these valves is also relatively short. For these reasons, the requirements of the process should be determined well, and the appropriate bearing material should be selected after the acceptable impermeability level is analyzed. Spheres and Bearings are coated with Tungsten Carbide, Nickel Based Alloys, SC1 and similar coating technologies to make them suitable for working under heavy conditions.

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