api 50005000 API 10000 API 15000 Ø C Ø B A H Ø C A H Ø B. HANDWHEEL OPERATED VALVE GEAR OPERATED VALVE API 6A MUD SERVICE GATE VALVE Working Pressure rating siZEAPI 6A flanges of class 5000 and below are often made of A105 carbon steel with a minimum yield strength of 45K, while API 6BX flanges of class 10000