Carbon steel bar is a kind of solid long steel, and the common ones are round steel, square steel, hexagonal steel, octagonal steel, etc.Round steel is often used to make reinforcing steel rebars、concrete rebar，bolts and various mechanical parts, as well as billets for seamless steel pipes.Square steel refers to steel that is rolled or processed into a square section, which can be divided into hot-rolled and cold-rolled.

Reinforcing steel refers to steel used for reinforced concrete and prestressed reinforced concrete. Reinforcing steel for reinforced concrete refers to straight or wire-shaped steel used for reinforced concrete reinforcement.