Deformed Steel Bar is ribbed steel bar with two longitudinal ribs and transverse ribs evenly distributed along the length. The shape of the transverse rib is three kinds of spiral shape, herringbone shape and crescent shape. Expressed in millimeters of nominal diameter. The nominal diameter of a deformed bar corresponds to the nominal diameter of a round bar of equal cross-section. The nominal diameter of the steel bars is 8-50 mm. The recommended diameters are 8, 12, 16, 20, 25, 32, 40 mm. Steel bars are mainly subjected to tensile stress in concrete. The deformed steel bar has a greater bonding ability with concrete due to the action of the ribs, and thus can better withstand the external force.