We are manufacturer of Carbon Steel Square Flanges that are the used for blocking a pipeline or making a stop. This is a type of disk that is machined like a standard flange, the difference being that the mounting holes are present around the perimeter. Also, the mating surface is machined with gasket sealing rings. It has some sort of opening for permitting the fluid to pass through. The Carbon Steel Square Flanges are used for connecting various pipes in the pipeline system.