api 5000API 6A - TYPE - 6B 34.5 MPA (5000 PSI). Size. B. OD. C. (MAX.) K. P. E. T. Q. X. BC. N. H 2) RING GASKET ACCORDING TO API 6AAPI has specified weld necks for many 6BX flanges, and not done so for many others, but API has provided the basis for determining the dimensions of a 6BX integral flange