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GB 1499.2-2024: Steel for the reinforcement of concrete - Part 2: Hot rolled ribbed bars
GB 1499.2-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.15
CCS H 44
Replacing GB/T 1499.2-2018
Steel for the reinforcement of concrete - Part 2.Hot rolled
ribbed bars
ISSUED ON. JUNE 25, 2024
IMPLEMENTED ON. SEPTEMBER 25, 2024
Issued by. State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
Introduction... 5
1 Scope... 6
2 Normative references... 6
3 Terms and definitions... 8
4 Classification, designation... 9
5 Size, shape, weight, and allowable deviation... 10
6 Smelting and performance... 14
7 Test methods... 18
8 Inspection rules... 21
9 Packaging, marks, and quality certification... 22
Annex A (informative) Formula for calculating the relative rib area of steel bars... 24
Annex B (normative) Macroscopic metallography, section Vickers hardness,
microstructure and inspection methods of steel bars... 25
Annex C (normative) Rules for characteristic value inspection... 28
Steel for the reinforcement of concrete - Part 2.Hot rolled
ribbed bars
1 Scope
This document specifies the classification, designation, size, shape, weight and
allowable deviation, smelting and performance, test methods, inspection rules,
packaging, marks and quality certificates for the hot rolled ribbed bars the
reinforcement of concrete (hereinafter referred to as steel bars).
This document is applicable to hot rolled bars and hot rolled bars of fine grains for the
reinforcement of concrete.
This document is not applicable to recycled steel bars and waste heat treated steel bars
that are re rolled from finished steel products.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 222, Permissible tolerances for chemical composition of steel products
GB/T 223.5, Steel and iron -- Determination of acid-soluble silicon and total silicon
content -- Reduced molybdosilicate spectrophotometric method
GB/T 223.11, Iron, steel and alloy -- Determination of chromium content -- Visual
titration or potentiometric titration method
GB/T 223.12, Methods for chemical analysis of iron, steel and alloy. The sodium
carbonate separation-diphenyl carbazide photometric method for the determination
of chromium content
GB/T 223.14, Methods for chemical analysis of iron, steel and alloy. The N-benzoyl-
N-phenylhydroxylamine extraction photometric method for the determination of
vanadium content
GB/T 223.17, Methods for chemical analysis of iron, steel and alloy -- The
diantipyrylmethane photometric method for the determination of titanium content
GB/T 223.19, Methods for chemical analysis of iron, steel and alloy. The
GB/T 20123, Steel and iron -- Determination of total carbon and sulfur content
Infrared absorption method after combustion in an induction furnace (routine
method)
GB/T 20124, Steel and iron -- Determination of nitrogen content -- Thermal
conductimetric method after fusion in a current of inert gas
GB/T 20125, Low-alloy steel -- Determination of multi-element contents --
Inductively coupled plasma atomic emission spectrometric method
GB/T 28900, Test methods of steel for reinforcement of concrete
JGJ 18, Specification for welding and acceptance of reinforcing steel bars
JGJ 107, Technical specification for mechanical splicing of steel reinforcing bars
YB/T 081, Rule for rounding off of numerical values and judgement of testing values
for technical standards of metallurgy
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 hot rolled bars
Steel bars delivered in hot-rolled condition.
3.2 hot rolled bars of fine grains
Fine grained steel bars formed through controlled rolling and controlled cooling
processes during hot rolling.
3.3 ribbed bars
Steel bars for concrete structures of which the cross-section is usually circular and the
surface is ribbed.
3.4 longitudinal rib
A uniform continuous rib parallel to the axis of the steel bar.
3.5 transverse rib
Other ribs that are not parallel to the axis of the steel bar.
3.6 crescent ribbed bars
A steel that that the longitudinal section of the transverse rib is crescent shaped and does
not intersect with the longitudinal rib.
3.7 nominal diameter
The diameter of a circle equal to the nominal cross-sectional area of the steel bar.
3.8 specific projected rib area
The ratio of the projected area of the transverse rib on the plane perpendicular to the
axis of the steel bar to the product of the nominal circumference of the steel bar and the
spacing between the transverse ribs.
3.9 rib height
The measured distance from the highest point of the rib to the surface of the core
perpendicular to the axis of the steel bar.
3.10 rib spacing
The distance between the centers of two adjacent transverse ribs measured parallel to
the axis of the steel bar.
3.11 characteristic value
The percentile value corresponding to a specified probability in an infinite number of
tests.
3.12 core
The cross-section of the steel bar does not include the transverse ribs and longitudinal
ribs.
4 Classification, designation
4.1 Steel bars are classified into 400, 500, and 600 grades based on their yield strength
characteristic values.
4.2 The composition and meaning of steel bar designations are shown in Table 1.
less than 45°. When the angle β is not greater than 70°, the direction of the
transverse ribs on the opposite sides of the steel bar shall be opposite.
b) The nominal spacing between transverse ribs shall not exceed 70% of the nominal
diameter of the steel bar.
c) The angle α between the side of the transverse rib and the surface of the steel bar
shall not be less than 45°.
d) The total gap between the ends of the transverse ribs on adjacent sides of the steel
bar (including the width of the longitudinal ribs) shall not exceed 20% of the
nominal circumference of the steel bar.
e) When the nominal diameter of the steel bar is not greater than 12 mm, the relative
rib area is not less than 0.055.When the nominal diameter is 14 mm and 16 mm,
the relative rib area is not less than 0.060.When the nominal diameter is greater
than 16 mm, the relative rib area shall not be less than 0.065.The calculation of
the relative rib area of steel bars is shown in Annex A.
5.3.2 Steel bars are divided into two types. those with longitudinal ribs and those
without longitudinal ribs. Crescent ribbed steel bars with longitudinal ribs are as shown
in Figure 1.The size and allowable deviation of steel bars shall comply with the
provisions of Table 3.The inner diameter size of crescent ribbed steel bars without
longitudinal ribs can be adjusted according to the requirements of both the supplier and
the purchaser based on Table 3.
5.3.3 When the allowable deviation between the actual weight and theoretical weight
of the steel bars meets the requirements in Table 4, the deviation of the inner diameter
of the steel bars and the height of the longitudinal ribs are not considered as delivery
conditions.
m - theoretical unit weight, in grams per millimeter (g/mm).
7.5 Macroscopic metallography, cross-sectional Vickers hardness, microstructure
inspection ...