api 5000The inside diameter of a # API 6A 5000 PSI weld neck flange is machined to match the inside diameter of the pipe. Tesco Steel & Engineering manufacture a wide range of hh qualityapi 6a - type - 6b 34.5 mpa (5000 psi) gbt 22513-2013 API 6A-TYPE-6B 34.5MPA (5000PSI)