Flanges are used to connect pipes with each other, to valves, to fittings, and to specialty items such as strainers and pressure vessels. A cover plate can be connected to create a "blind flange". Flanges are joined by bolting, and sealing is often completed with the use of gaskets or other methods.flanges are installed onto a stub end, which is then welded to the hose. The face of the stub end becomes the sealing surface for a floating flange. Some stub ends are made by flaring a piece of pipe on one end; others are made by machining the stub end out of solid material.