The nominal diameter of steel bar is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, 40 mm. Steel: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Reinforcement mainly undergoes tensile stress in concrete. Because of the action of rib, deformed steel bar and concrete have greater bonding ability, so it can bear the action of external force better. Steel bars are widely used in various building structures. Especially large, heavy, light thin-walled and high-rise building structures