... FLANGE, BLIND FLANGE. Pressure Class: 75, 150, 300, 400, 600, 900 ASME/ANSI B16.36: (ORIFICE FLANGES) WELDING NECK FLANGE, SLIPON ... FLANGE, THREADED FLANGE. Pressure Class: 300, 400, 600, 900, 1500, ... MSS SP44: WELDING NECK FLANGE, BLIND FLANGE. Pressure Class: 300, 400, 600, 900 API 6A: WELDING NECK FLANGE, THREAD FLANGE, ...