ASTM A500 black steel pipe is an excellent candidate for most processing. A500 bare steel pipes have a semi-smooth surface coated with black lacquer. Black steel pipe are not pressure tested, and primarily designed for structural use only. Common applications include railings, fencing, bollards, and gas systems. ASTM A500 is the standards specification for cold-formed welded and seamless carbon steel structural tubing in rounds and shapes.
A500 bare steel pipe sizes are specified by two non-dimensional numbers. Nominal pipe size (NPS) or inside diameter (ID), and pipe schedule (SCH) referring to the wall thickness.