The letters on the steel bars are registered factory names or trademarks. The number in front of the steel bar represents the grade of the steel bar, such as 3 for grade 2 steel, 4 for grade 3 steel and 5 for grade 4 steel. The last two digits represent the specifications of steel bars, and the letters between grades and specifications represent the manufacturers of steel bars.

The grade of steel bars is represented by Arabic numerals or Arabic numerals plus English letters, HRB335, HRB400 and HRB500 are represented by 3, 4 and 5 respectively, and HRB335, HRB400 and HRB500 are represented by C3, C4 and C5 respectively. The name of the factory is indicated by the Chinese phonetic prefix. Nominal diameters in millimeters are expressed in Arabic numerals.

4GJ22 These are the basic information of steel bars, which is equivalent to ID card information. The steel plant representing grade 4 steel (HRB500) code GJ is Hanggang; Then the nominal diameter is 22.