Steel bars are ribbed bars, which are divided into hot-rolled ribbed bars and cold-rolled ribbed bars. Rebar is also called deformed steel bar or special-shaped steel bar. Different from ordinary round steel, there are longitudinal bars and transverse bars on the surface, which are usually evenly distributed along the length direction. Rebar is a kind of small steel, which is mainly used for the skeleton of reinforced concrete building components. It is required to have certain mechanical strength, bending deformation performance and process welding performance in use. The raw billet used to produce rebar is carbon structural steel or low alloy structural steel that has been killed and melted, and the finished rebar is delivered in hot-rolled shape, normalized or hot-rolled state.
There are two common classification methods of steel bars: one is to classify according to the geometric shape of steel bars, and the other is to classify or classify according to the cross-sectional shape of transverse bars and the spacing between bars. For example, steel bars are classified into Type I and Type II in British Standard (BS4449). This classification mainly reflects the grip performance of steel bars. Secondly, rebar is classified according to performance (grade). For example, in China standard (GB 1499), rebar is divided into three grades according to strength grade (yield point/tensile strength). According to Japanese industrial standard (JISG3 1 12), rebar can be divided into five categories according to its comprehensiveness. British Standard (BS446 1) also stipulates several grades of steel bar performance test. In addition, steel bars can also be classified according to their uses, such as ordinary steel bars for reinforced concrete and heat-treated steel bars for prestressed reinforced concrete.