api5000API 6A Type 6B 5000 PSI Weld Neck & Blind Flanges Manufacturers & suppliers in India Hh pressure steel flange, forged flanges, API 6A Type 6B 5000 PSI Weld Neck & Blind FlangesAPI 5000, 10000 are used in reference to wellhead 'christmas tree' pressure ratings as well used for the wing valve, master valve ratings. There may be hher classes as