Introduction to Flange Bolts and Nuts What are flange bolts and nuts? The flange bolts and nuts are the type of fastener mainly composed of a hexagonal head, a flange plate (the gasket below the hexagon is fixed together with the hexagon), and a screw (a cylindrical body with external threads). It needs to be matched with a nut and used to tighten and connect two parts with thr... https://www.flangegasketboltkits.com