Metal to Metal Seal of Wedge Gate ValvesHow can I consider the additional preload needed in the seat-gate valve system to maintain the compressive loadon a STELLITE (Seat HF - Wedge HF / Roughness Ra=0.2 lapp) seal surface after internal pressure is applied.Can I use for this problem the Gasket Factors "M" and "Y" (usually used for metallic gasket / flange design) and the related theory to estimate the required loads?For my experience as Valve Designer a gate valve stem has to support 3 major types of forces: Seat Friction ( pressure and wedge angle depending)