The blind flange is basically a flange that does not have a hub or a bored center. Blind flanges is a solid disk used to seal the end of piping systems or pressure vessel openings. They are commonly used for testing the flow of gas or liquid through a pipe or vessel, in addition to allowing for easy access to the pipe in case work must be done inside the line. Similar to a regular flange, a blind flange has mounting holes around the perimeter and the gasket sealing rings are machined into the mating surface.

The most common two types are the flat face (FF) and the raised face (RF) blind flange. A flat face flange is completely smooth and level across the surface. The raised face flange has a slightly elevated middle area that creates two levels on the surface of the flange. Some blind flanges will be required a 1/2" or 3/4" FNPT threaded hole or SW hole in the center。

We GUTE is the manufacture that provide all kinds of  steel flanges like Blind Flanges, Plate flat Flanges, Weld Neck Flanges, Slip On Flanges, Socket Weld Flanges, and so on, and also other special flanges according to the client's requirement.
Blind Flange Specification:

Blind Flange Material Grades: