GB/T 1499.2-2018 (GB/T1499.2-2018)

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GB/T 1499.2-2018: PDF in English (GBT 1499.2-2018)

GB/T 1499.2-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.60
H 44
Replacing GB/T 1499.2-2007
Steel for the reinforcement of concrete -
Part 2. Hot rolled ribbed bars
(ISO 6935-2.2015, Steel for the reinforcement of concrete -
Part 2. Ribbed bars, NEQ)
ISSUED ON. FEBRUARY 06, 2018
IMPLEMENTED ON. NOVEMBER 01, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 4
1 Scope ... 7
2 Normative references ... 7
3 Terms and definitions ... 9
4 Classification, grade ... 11
5 Order content ... 11
6 Dimension, shape, weight and tolerance ... 12
6.1 Nominal diameter range ... 12
6.2 Nominal cross-sectional area and theoretical weight ... 12
6.3 Surface shape and dimension tolerances of bars ... 12
6.4 Length and tolerance ... 16
6.5 Curvature and end ... 16
6.6 Weight and tolerance ... 16
7 Technical requirements ... 17
7.1 Smelting method ... 17
7.2 Grades and chemical composition ... 17
7.3 Delivery type ... 18
7.4 Mechanical properties ... 18
7.5 Process performance ... 19
7.6 Fatigue performance ... 19
7.7 Connection performance ... 19
7.8 Grain size ... 20
7.9 Metallographic structure ... 20
7.10 Surface quality ... 20
8 Test methods ... 20
8.1 Inspection items ... 20
8.2 Tensile, bending, reverse bending test ... 22
8.3 Dimension measurement ... 22
8.4 Measurement of weight deviation ... 23
8.5 Macroscopic metallography, cross-section Vickers hardness,
microstructure inspection ... 23
8.6 Rounding off of numerical values ... 23
9 Inspection rules ... 23
9.1 Inspection classification ... 23
9.2 Characteristic value inspection ... 23
9.3 Delivery inspection ... 24
10 Packaging, marking, and quality certificate ... 24
Annex A (informative) Calculation formula for specific projected rib area of bars
... 26
Annex B (normative) Macroscopic metallography, cross-section Vickers
hardness, microstructure of bars and inspection methods ... 27
Annex C (normative) Characteristic value inspection rules ... 30
Foreword
GB/T 1499 “Steel for the reinforcement of concrete” consists of three parts.
- Part 1. Hot rolled plain bars;
- Part 2. Hot rolled ribbed bars;
- Part 3. Welded fabric.
This Part is Part 2 of GB/T 1499.
This Part was drafted in accordance with the rules given in GB/T 1.1-2009.
This Part replaces GB/T 1499.2-2007 “Steel for the reinforcement of concrete -
Part 2. Hot rolled bars”.
Compared with GB/T 1499.2-2007, the main changes of this Part are as follows.
- ADD the smelting method;
- CANCEL the 335 MPa grade bar;
- ADD the 600 MPa grade bar;
- ADD the bars of which the grade is with E;
- Appropriately TIGHTEN the length tolerance and curvature;
- Appropriately TIGHTEN the weight tolerance, making it clear that the weight
tolerance does not allow reinspection;
- REQUIRE the reverse bending test of bars of which the grade is with E AS
a routine inspection item;
- ADD the specifications for the fatigue test method for bars;
- ADD the specifications for the inspection of metallographic structure;
- ADD macroscopic metallography, cross-section Vickers hardness,
microstructure, and their inspection methods;
- ADD the measurement method for the gap at the end of transverse ribs;
- The surface marking is changed from the “Registered factory name (or
trademark)” TO “The serial number of the production license of hot rolled
bar products obtained by the enterprise (the last 3 digits)”; DELETE “For
bars with a nominal diameter not greater than 10 mm, the marking may be
Steel for the reinforcement of concrete
- Part 2. Hot rolled ribbed bars
1 Scope
This Part of GB/T 1499 specifies the terms and definitions, classification, grade,
order content, dimension, shape, weight and tolerance, technical requirements,
test methods, inspection rules, packaging, marking and quality certificate of hot
rolled ribbed bars for the reinforcement of concrete (hereinafter referred to as
bars).
This Part applies to hot rolled ribbed bars and hot rolled ribbed bars of fine
grains for the reinforcement of concrete.
This Part does not apply to re-rolled bars and residual heat-treated bars rolled
from finished steel.
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-
benzoy-N-phenylhydroxylamine extraction photometric method for the
determination of vanadium 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 (routine method)
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
YB/T 081 Rule for rounding off of numerical values and judgement of testing
values for technical standards of metallurgy
JGJ 18 Specification for welding and acceptance of reinforcing steel bars
JGJ 107 Technical specification for mechanical splicing of steel reinforcing
bars
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1
hot rolled bars
Bars delivered in hot rolled condition.
3.2
hot rolled bars of fine grains
In the hot rolling process, bars of fine grains formed by controlled rolling and
controlled cooling processes, having a grain size of level 9 or finer.
3.3
ribbed bars
Steel for concrete structures, of which the cross-section is usually round and
the surface is with ribs.
3.4
longitudinal rib
θ - longitudinal rib angle;
a - longitudinal rib top width;
l - transverse rib spacing;
b - transverse rib top width;
fi - transverse rib end gap.
Figure 1 -- Surface and cross-sectional
shape of crescent ribbed bar (with longitudinal ribs)
6.4 Length and tolerance
6.4.1 Length
6.4.1.1 Bars are usually delivered in cut length. The specific delivery length
shall be specified in the contract.
6.4.1.2 Bars may be delivered in coils. Each coil shall consist of a bar. It is
allowed that there are 5 % of the number of coils (two coils when there are less
than two coils) consisting of two bars in each batch. The coil weight is agreed
upon between supply and demand parties.
6.4.2 Length tolerance
The tolerance of the length of the bars delivered in cut length is ൅50 0 mm.
6.5 Curvature and end
The curvature of straight bars shall not affect normal use. The curvature per
meter is less than 4 mm. The total curvature is not more than 0.4 % of the total
length of the bar.
The end of bars shall be cut straight, and local deformation shall not affect use.
6.6 Weight and tolerance
6.6.1 Bars may be delivered in theoretical weight, or in actual weight. When
delivered in theoretical weight, the theoretical weight is the length of the bar
multiplied by the theoretical weight per meter of the bar in Table 2.
6.6.2 The tolerance of the actual weight and the theoretical weight of bars shall
comply with the specifications of Table 4.
and joints of bars shall comply with the specifications of relevant standards such
as JGJ 18, JGJ 107.
7.7.2 The welding process of HRBF500 and HRBF500E bars shall be
determined by tests.
7.7.3 It is recommended to connect HRB600 bars using mechanical connection.
7.8 Grain size
The actual grain size of hot rolled bars of fine grains is Level 9 or finer. If this is
guaranteed by the supply party, the grain size inspection may be exempted.
7.9 Metallographic structure
The metallurgical structure of bars shall be mainly ferrite plus pearlite, and
tempered martensite shall not appear on the core. The macroscopic metallurgy,
cross-section Vickers hardness and microstructure of bars shall comply with
the specifications of Annex B. If they are guaranteed by the supply party, the
inspection may be exempted.
7.10 Surface quality
7.10.1 Bars shall be free from harmful surface defects.
7.10.2 When the weight, dimension, cross-sectional area and mechanical
properties of wire-brushed specimens are not lower than the requirements of
Clauses 6 and 7, the scales, surface irregularities or oxide scales are not
regarded as the reason for rejection.
7.10.3 When specimens with surface defects other than those specified in
7.10.2 do not meet the mechanical properties or process performance
requirements, the defects are considered to be harmful.
8 Test methods
8.1 Inspection items
8.1.1 The inspection items, sampling methods and test methods for each batch
of bars shall comply with the specifications of Table 8.
and demand parties;
c) Third-party product certification and arbitration inspection.
9.2.2 The characteristic value inspection shall be conducted according to the
rules of Annex C.
9.3 Delivery inspection
9.3.1 Applicable situation
The delivery inspection applies to the inspection of bar acceptance batches.
9.3.2 Batching rules
9.3.2.1 Bars shall be inspected and accepted in batches. Each batch shall
consist of bars of the same grade, the same furnace number and the same
specification. The weight of each batch is usually not more than 60 t. For the
part over 60 t, for each additional 40 t (or the remainder for those less than 40
t), add a tensile test specimen and a bend test specimen.
9.3.2.2 It is permissible to form mixed batches with bars of the same batch
number, the same smelting method, the same casting method and different
furnace numbers. However, the difference between the carbon content of each
furnace number is not more than 0.02 %, and the difference between the
manganese content is not more than 0.15 %. The weight of the mixed batch is
not more than 60 t.
9.3.3 Inspection items and sampling quantity
The inspection items and sampling quantity of bars shall comply with the
specifications Table 8 and 9.3.2.1.
9.3.4 Inspection results
The inspection results of each inspection item for bars (including bars after
coiling and straightening) shall comply with the relevant specifications of
Clauses 6 and 7.
9.3.5 Reinspection and determination
The reinspection and determination of bars shall comply with the specifications
of GB/T 17505. The weight deviation items of bars do not allow reinspection.
10 Packaging, marking, and quality certificate
10.1 The surface marking of bars shall comply with the following specifications.
Annex C
(normative)
Characteristic value inspection rules
C.1 Test batching and sampling quantity
C.1.1 Test batching
For tests, delivery shall be subdivided into test batches. The batching rules shall
comply with the specifications of 9.3.2.
C.1.2 Sampling quantity per batch
C.1.2.1 For chemical composition (finished product analysis), two specimens
shall be taken from different piece of bars.
C.1.2.2 For tests of mechanical properties, 15 specimens shall be taken from
different piece of bars (if 60 specimens are applicable, see C.2.1).
C.2 Evaluation of test results
C.2.1 Parametric inspection
To inspect the specified properties, such as the characteristic parameters ReL,
Rm, Agt, or A, the following parameters shall be determined.
a) all single values Xi (n = 15) for 15 specimens;
b) the average value m15 (n = 15);
c) the standard deviation S15 (n = 15).
If all the properties meet the condition given by formula (C.1), the test batch
meets the requirements.
where.
fk - the required characteristic value;
2.33 - the value of acceptance coefficient k when n = 15, 90 % confidence
level (1 - a = 0.90) and failure rate 5 % (P = 0.95).
......
 
(Above excerpt was released on 2018-07-21, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT1499.2-2018