The ribbed steel bar sign has undergone major changes. In addition to the brand mark rolled on the surface of the ribbed steel bar, the registered factory name (or trademark) and diameter millimeter number can be rolled sequentially. The steel bar grade is represented by Arabic numerals plus English letters. HRB335, HRB400, and HRB500 are represented by 3, 4, and 5 respectively. HRBF335, HRBF400, and HRBF500 are represented by C3, C4, and C5 respectively. The factory name is represented by the prefix Chinese Pinyin; the diameter is in millimeters. Expressed in Arabic numerals. Compared with the provisions of the old standards HRB335, HRB400, and HRB500 represented by 2, 3, and 4 respectively, there are major changes, which should attract the attention of relevant construction, supervision, and testing personnel. That is to say, if you see "4" engraved on the surface of the steel bar today, it is HRB400, the so-called Grade III rebar. However, in the future, Grade III rebar will not be weighed and will be called HRB400. Similarly, if you see "4" engraved on the surface of the steel bar today, 3", whether it is the previous grade III steel or grade II steel should be carefully checked.