| Rigid Seat Rigid seats are available for abrasive application including reclaimed fiber systems and applications with suspended chemical solids. The rigid seat provides shutoff performance to FCI 70-2/ANSI Class IV. Materials include 317 stainless steel and Hastelloy C. For enhanced abrasion resistance, a 317 stainless steel seat with tungsten carbide seating surface and solid Stellite® alloy bearing are available. An optional Inconel spring can be substitute fro the 177 PH stainless steel seat spring when added corrosion resistance is required. The rigid seat is designed for flow-to-open operations and is field-interchangeable with the reinforced PTFE and flexible metal seats. Stellite® is a registered trademark of Stoody Deloro Stellite, Inc |