Plain round steel bars are actually small round steel bars and coiled round bars of ordinary low-carbon steel. Deformed steel bars are steel bars with ribs on the surface, usually with two longitudinal ribs and transverse ribs evenly distributed along the length. The shapes of the transverse ribs are spiral, herringbone, and crescent. It is expressed in millimeters of nominal diameter. The nominal diameter of deformed steel bars is equivalent to the nominal diameter of plain round steel bars with the same cross section. Steel grades: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Steel bars mainly bear tensile stress in concrete. Due to the effect of ribs, deformed steel bars have greater bonding ability with concrete, so they can better withstand the effects of external forces. Steel bars are widely used in various building structures. Especially large, heavy, light thin-walled and high-rise building structures.