Flanges are integral components in piping systems, connecting pipes, valves, and equipment. Common types include weld neck, slip-on, threaded, and socket weld flanges. They are made from materials like carbon steel or stainless steel, with various pressure ratings (e.g., 150, 300, 600 PSI). Flanges have different facings, such as flat face, raised face, or ring-type joint, and require gaskets for a secure seal.