Rebar is a hot rolled ribbed bar commonly known. 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 Hotrolled, Ribbed and Bars respectively.Hot rolled ribbed steel bar is divided into two grades HRB335 (the old brand name is 20MnSi), three grades HRB400 (the old brand name is 20MnSiV, 20MnSinB, 20MnTi) and four grades HRB500.

The surface of the steel bar must not be cracked, scarred and folded.

The surface of the steel bar is allowed to have a convex block, but shall not exceed the height of the transverse rib, the depth and height of other defects on the surface of the steel bar shall not be greater than the allowable deviation of the size of the location.

There are two common classification methods of rebar: one is the classification of geometric shape, according to the shape of the cross section and the spacing of the ribs are different classification or classification, such as the British standard (BS4449), the rebar is divided into I type, flat type. This classification mainly reflects the grip performance of rebar.Second, the performance classification (level), such as China's current implementation standards, rebar for (G B1499.2-2007) wire for 1499.1-2008), according to the strength level (yield point/tensile strength) will be divided into three grades of rebar; Japanese industrial standard (JI SG3112), according to the comprehensive performance will be divided into five types of rebar;British standard (BS4461), also provides a number of grades of rebar performance testIn addition can also be classified according to the use of rebar, such as divided into reinforced concrete with ordinary steel and prestressed reinforced concrete with heat treatment steel.