Flanged fittings connect with pipe to transport natural or propane gas, water, steam, and air to residential, construction, and manufacturing applications. Flanged fittings mechanically connect two pipes. Flanged joints include a gasket between joints to provide a seal. Uncoated black steel flanges, also called black malleable iron, are made from corrosion-resistant ungalvanized steel with a scaly, dark-colored iron oxide coating. Flanged fittings come in a variety of sizes and shapes.