api5000API 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 that the manufacturer may attach to aWe are a API 6A flange manufacturer,API 6A Type 6B 5000 psi(34.5 MPa) Weld Neck RTJ Flange,API 6 B 3000 psi WN RTJ Flange,API 6BX 10000 PSI Weld Neck Flange,API weld neck flange