Hot rolled ribbed steel bars are divided into three grades: Grade II HRB335 (old brand name 20MnSi), Grade III HRB400 (old brand names 20 mnsi, 20MnSiNb and 20Mnti) and Grade IV HRB500.
1, symbol of primary reinforcement:
2, secondary reinforcement symbol:
3. Symbol of tertiary reinforcement:
Extended materials:
Rebar is a common name for hot-rolled ribbed steel bars. The grade of common hot rolled steel bar consists of HRB and the lowest yield point of this grade. H, r and b are the initials of the words Hotrolled, Ribbed and Bars, respectively.
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.
Second, according to the performance classification (grade), for example, according to the current implementation standards in China, rebar is (G B 1499.2-2007), wire is 1499. 1-2008), and rebar is divided into three grades according to the strength grade (yield point/tensile strength).
References:
Baidu encyclopedia-reinforcement