In the construction industry, grade II rebar and grade III rebar are known in the past. In the new standard, grade II rebar is called HRB335, and grade III rebar is called HRB400.

The grades of hot-rolled ribbed bars consist of HRB and the minimum yield point of the grade. H, R, and B are the English first letters of Hotrolled, Ribbbed, and Bars. Hot-rolled ribbed steel bars are classified into HRB335 (old name is 20MnSi) and HRB400 (brand name is 20MnSiV, 20MnSiNb, 20MnTi). Under normal circumstances, the theoretical weights of these types of steel bars are the same when the nominal diameter and length are equal.

Reinforced concrete reinforcement refers to straight or rod-shaped steel used for reinforcement of reinforced concrete. Its appearance is divided into two kinds, light round steel bar and Deformed Steel Bar. The delivery status is straight bar and round bar. The light round bar is actually a small round steel and coil of ordinary low carbon steel. Deformed rebar is a surface ribbed rebar, usually with two longitudinal ribs and transverse ribs that are evenly distributed along the length. The lateral ribs are spiral, herringbone and crescent shaped. It is expressed in millimeters of nominal diameter. The nominal diameter of the deformed bar corresponds to the nominal diameter of the round bar with equal cross section. The nominal diameter of the steel bars is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, and 40 mm. Steel types: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Reinforced steel is mainly subjected to tensile stress in concrete. Because of the effect of ribs, Deformed Steel Bars have a greater ability to bond with concrete and can therefore better withstand the effects of external forces. Reinforcing steel is widely used in various building structures, especially large-scale, heavy-duty, light-weight thin-walled and high-rise building structures. Tianhai Iron and Steel Co., Ltd. has been engaged in secondary and tertiary rebar, precision rolled rebar, and wire rod sales for 20 years.