Symbol 1 is the grade of hot-rolled plain round steel bar: HPB300. The meaning of the grade is: consisting of HPB + yield strength characteristic value (300MPa). ?Meaning of English letters: HPB - the abbreviation of Hot?rolled?Plain?Bars.
Ordinary hot-rolled ribbed steel bar grades: HRB335, HRB400, HRB500; the meaning of the grade: composed of HRB + yield strength characteristic values ??(335MPa, 400MPa, 500MPa). On the steel bars, the grade marks are represented by 3, 4, and 5 respectively. The meaning of the English letters: HRB - the abbreviation of Hot?rolled?Ribbed?Bars.
Symbol 2 is the grade of ordinary hot-rolled ribbed steel bar: HRB335. The composition and meaning of the grade: consists of HRB + yield strength characteristic value (335MPa). On the steel bars, the grade mark is represented by 3.
Symbol 3 is the grade of ordinary hot-rolled ribbed steel bar: HRB400. The composition and meaning of the grade: consists of HRB + yield strength characteristic value (400MPa). On the steel bars, the grade mark is represented by 4.
Symbol 4 is the grade of waste heat treated ribbed steel bar: RRB400. The meaning of the grade is: composed of RRB + yield strength characteristic value (400MPa). RRB - the abbreviation for Remained heat treatment Ribbed Steel Bars. The design symbol is: symbol plus the subscript R.
10 Packaging, marking and quality certificate
10.1 The surface markings of ribbed steel bars shall comply with the following requirements:
a) The ribbed steel bars shall be marked on their surface After rolling on the brand mark, you can also roll on the registered factory name (or trademark) and the nominal diameter in millimeters.
b) The steel bar grade is represented by Arabic numerals plus English letters. RRB400 is represented by K4; RRB500 is represented by K5; RRB400?W is represented by K?W 4. The factory name starts with the Chinese pinyin. The nominal diameter in millimeters is expressed in Arabic numerals.
C) For steel bars with a nominal diameter of no more than 10mm, the rolling mark does not need to be rolled, and the sign can be hung.
d) The sign should be clear and clear. The size of the sign should be appropriately specified by the supplier according to the size of the steel bar. The transverse ribs that intersect with the sign can be eliminated.
Bars
Ribbed
Remained
The grades and symbols of ordinary steel bars are shown in the table below , extracted from "Code for Design of Concrete Structures" GB 50010-2010 (2015 Edition)?:
Fine-grained hot-rolled steel bar grades: HRBF?335,?HRBF400,?HRBF?500; the meaning of the composition of the grades: ?Consists of ?HRBF? + yield strength characteristic value (335MPa, 400MPa, 500MPa). On the steel bars, the grade marks are represented by C3, C4, and C5 respectively. HRBF? English letter meaning: HRB - the English abbreviation of hot rolled ribbed steel bar (Hot? rolled Ribbed Bars) followed by the English initials of "Fine". The design symbol is: Add the subscript F to the symbol.
"Steel for reinforced concrete Part 2: Hot-rolled ribbed steel bars" GB1499.2-2007:
10 Packaging, marking and quality certificate
10.1 The surface markings of ribbed steel bars should comply with the following regulations:
10.1.1 The ribbed steel bars should be rolled with the grade mark on their surface, and the registered factory name (or trademark) and nominal name can also be rolled in turn. Diameter in millimeters.
10.1.2 The steel bar grade is represented by Arabic numerals or Arabic numerals plus English letters. HRB335, HRB400 and HRB500 are represented by 3, 4 and 5 respectively. HRBF 335, HRBF400 and HRBF 500 are represented by C3, C4 and C5 means. The factory name starts with the Chinese pinyin. The nominal diameter in millimeters is expressed in Arabic numerals.
10.1.3 For steel bars with a nominal diameter of no more than 10 mm, the rolling mark does not need to be rolled, and the sign can be hung. 10.1.4 The mark should be clear and clear. The size of the mark shall be appropriately specified by the supplier according to the size of the steel bar. The transverse ribs intersecting with the mark may be eliminated.
10.2 Steel bars with E in the grade (such as HRB400E, HRBF400E, etc.) should be clearly stated on the signboard and quality certificate.
From the "Code for Design of Concrete Structures" GB 50010-2010 (2015 edition) table, steel bars are only divided into grades, symbols, standard values ??of yield strength, and standard values ??of ultimate strength.
From "Steel for Reinforced Concrete Part 1: Hot-rolled Plain Steel Bars" GB1499.1-2008 and "Steel for Reinforced Concrete Part 2: Hot-rolled Ribbed Steel Bars" GB1499.2-2007) Look, steel bars are no longer called grades: I, II, III, and IV, but only categories and grades. They are divided into grades 300, 335, 400, and 500 according to the yield strength characteristic value. I excerpt a passage (illustration) from the preface of the acceptance specification for reference:
10.1.1 The ribbed steel bar should be rolled with a grade mark on its surface, and the registered factory name (or trademark) can also be rolled in turn. ) and nominal diameter in millimeters.
10.1.2 The steel bar grade is represented by Arabic numerals plus English letters, ?HRB335?, HRB400, and HRB500 are represented by 3, 4, and 5 respectively, and HRBF335, HRBF400, and HRBF500 are represented by C3, C4, and C5 respectively; The factory name is represented by the prefix Chinese Pinyin; the diameter in millimeters is represented by Arabic numerals. The ribbed steel bar should be rolled with a brand mark on its surface, and the registered factory name (or trademark) and nominal diameter in millimeters can also be rolled on it. 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 inspection 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", is it the previous grade III steel or grade II steel? Especially if RRB400 is represented by K4 and RRB500 is represented by K5, what grade of steel should we call it? It should be checked carefully.
10.2 Steel bars with E in the grade (such as HRB400E, HRBF400E, etc.) should be clearly stated on the signboard and quality certificate.
Reference materials: "Code for Design of Concrete Structures" GB 50010-2010 (2015 Edition)?, "Steel for Reinforced Concrete Part 1: Hot-rolled Plain Steel Bars" GB1499.1-2008, "For Reinforced Concrete" Steel Part 2: Hot-rolled ribbed steel bars" GB1499.2-2007, "Waste heat treated ribbed steel bars for reinforced concrete" GB13014-2013.