When steel pipe is forged, a black oxide scale forms on its surface to give it the finish which is seen on this type of pipe. Because steel is subject to rust and corrosion, the factory also coats it with protective oil. Those black steel are used for manufacturing pipe and tube, which will not rust for a long time and requires very little maintenance. It is sold in standard 21-foot lengths TBE.

Black steel pipes and tubing are cut and threaded to fit the job. Fittings for this type of pipe are of black malleable (soft) cast iron. They connect by screwing onto the threaded pipe, after applying a small amount of pipe joint compound on the threads. Larger diameter pipe is welded rather than threaded. Black steel pipe is cut either with a heavy-duty tube cutter or cutoff saw or by hacksaw.