Rebar is a common name for hot-rolled ribbed steel bars. The grade of ordinary hot-rolled steel bar consists of HRB and the minimum yield point of the grade. H, R, and B are the first letters of the three words, Hotrolled, Ribbed, and Bars, respectively.

The hot-rolled ribbed steel bar is divided into three grades: HRB335 (the old grade is 20MnSi), grade three HRB400 (the old grade is 20MnSiV, 20MnSiNb, 20Mnti), and grade four HRB500.

There are two commonly used classification methods for rebar: one is classification by geometric shape, which is classified or classified according to the cross-sectional shape of the transverse rib and the spacing of the ribs. Type II. This classification mainly reflects the gripping performance of the rebar. The second is performance classification (grade), such as my country's current implementation standard, rebar is (GB1499.2-2007) wire is 1499.1-2008), according to the strength level (yield point/tensile strength) The rebar is divided into 3 grades; in Japanese Industrial Standard (JI SG3112), rebar is divided into 5 types according to comprehensive performance; in British Standard (BS4461), several grades of rebar performance test are also specified. In addition, rebars 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.

Specification

The specification requirements of rebar should be listed in the import and export trade contract. Generally, it should include the standard grade (type code), the nominal diameter of the steel bar, the nominal weight (quality), the specified length and the tolerance value of the above indicators. Chinese standards recommend rebar series with nominal diameters of 6, 8, 10, 12, 16, 20, 25, 32, 40, and 50mm. The supply length is divided into two types: fixed length and double length. The selection range of fixed length of my country's export rebar is 6-12m, and the selection range of Japanese-made rebar is 3.5-10m; if there is no requirement in the contract for domestic domestic rebar, the fixed length is usually 9m and 12m.

Appearance Quality

①Surface quality. Relevant standards stipulate the surface quality of rebar, which requires that the ends should be cut straight, and the surface should not have cracks, scars and folds, and there should be no harmful defects in use.

②Allowable value of external dimension deviation. The requirements for the curvature of the rebar and the geometry of the rebar are specified in the relevant standards.