api 5000Refer API 6a 6b And 6bx Flanges Weht Chart According to ASME B16.5 And (American Petroleum Institute) API 6A 5000 Flange Dimensions. Api 6a Flange Material Specification.The 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 quality