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Construction Industry Standard of the People's Republic of China JG3046-1998
Cold-rolled and twisted bars
Published on February 9, 1998
Implemented on May 1, 1998
Published by the Ministry of Construction of the People's Republic of China
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JG3046-1998
This standard is compiled based on the basic provisions of the national standard "Guidelines for Standardization Work" (GB/T1.1-1993) and with reference to the British standard BS4461 (1988 edition). This standard integrates more than ten local standards and regulations on cold-rolled and twisted steel bars and their application technology, and is compiled after coordination and optimization of raw material selection, processing equipment, process level, design and construction characteristics. This standard shall be implemented from May 1, 1998. Appendix A of this standard is the standard appendix, and Appendix B is the suggested appendix. This standard was proposed by the Standard and Quota Research Institute of the Ministry of Construction. This standard is managed by the China Academy of Building Research, the technical management unit of the construction engineering standards of the Ministry of Construction.
East Standard Drafting Units: Beijing Institute of Architectural Design, Beijing Institute of Building Engineering, China Academy of Building Research, Jiangsu Institute of Building Research, Zhejiang University of Technology, Shanghai Tongji University, Beijing Institute of Civil Engineering, Beijing Construction Engineering Group Sixth Construction Engineering Company, Guangxi Zhuang Autonomous Region Second Construction Engineering Company, Jiaxing Zhenhua Machinery Manufacturing Co., Ltd., Xingtai Zhongda Construction Equipment Research Institute, Shenzhen Xingmeng Cold-rolled Deformed Steel Bar Co., Ltd.
Main drafters of this standard: Zhang Chengqi, Zhou Bin, Wu Jiaxiong, Wang Shihui, Xu Youlin, Li Guoli, Gao Benli, Zhang Junlin, Li Rongyuan, Xiao Jiafu, Li Jingyi, Lin Hongyu, Shen Ailan, Li Dongqing.
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Construction Industry Standard of the People's Republic of China Rolled
Cold-rolled and twisted bars Scope
JG3046——1998
This standard specifies the definition, classification, technical requirements, test methods, inspection rules, marking, packaging, transportation, storage, etc. of cold-rolled and twisted bars. This standard applies to cold-rolled and twisted bars used in reinforced concrete structural members. Referenced Standards
The provisions contained in the listed standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB701--91/Low carbon steel hot rolled round wire rod
GB223.69-89
GB228---87
GB2101--89
YB4027--91
3 Definitions
Chemical analysis methods for steel and alloys Combustion gas volumetric method for determination of carbon content
Metal tensile test methods
Bending test methods for all metals
General provisions for acceptance, packaging, marking and quality certification of steel sections
Low carbon steel non-torsion controlled cold and hot rolled wire rod (high-speed wire) Approved by the Ministry of Construction of the People's Republic of China on February 9, 1998 Engineering Construction Standard Full Text Information System
Implementation on May 1, 1998
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This standard adopts the following definitions.
3.1 Cold-rolled and twisted bars Cold-rolled and twisted bars are hot-rolled low-carbon steel bars that are straightened, cold-rolled and cold-twisted by a special cold-rolling and twisting machine to form a continuous spiral steel bar with a specified cross-sectional shape and pitch (Figure 1). 3.2 Pitch
The distance along the axis of the steel bar that the cross-sectional position of the cold-rolled and twisted steel bar moves in half a cycle (180°) (Figure 1).
3.3 Rolled thickness
The smaller side dimension of the rectangular cross-section or the short diagonal dimension of the rhombus cross-section after the cold-rolled and twisted steel bar is formed (Figure 1).
Chengzhi Zhiming
mark diametes
The nominal diameter (d) of the raw material (parent material) before rolling, marked with the symbol $. Engineering Construction Standard Full-text Information System
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Flattening thickness: ten
Figure 1 Shape and cross-section of cold-rolled twisted steel bars
Classification and model
Cold-rolled twisted steel bars are divided into two types according to their cross-sectional shapes: one is type I for a rectangular cross-section:
type I for a diamond cross-section.
4.2 Model
The model marking of cold-rolled twisted steel bars consists of four parts: product name code, characteristic code, main parameter code and modification code:
Modification code: AB, C
Main parameter code: Type I, Type II
Characteristic code: Marking diameter symbol
Name code: LZN
Marking example: cold-rolled twisted steel bars, marked diameter is 10mm, rectangular section. LZN@10(D)
5 Technical requirements
5.1 Raw materials
5.1.1 The raw materials used in the production of cold-rolled twisted steel bars should preferably be low-carbon steel non-torsion controlled cold hot-rolled wire rods (high-speed wire rods) that meet the requirements of YB4027, and low-carbon steel hot-rolled round wire rods that meet the requirements of GB701 can also be used.
The raw materials used are Q235 and Q215. However, when Q215 is used, the carbon content is less than 0.12%
5.2 Flattening thickness, pitch, nominal cross-sectional area, nominal weight and allowable deviation of cold-rolled twisted steel bars
5.2.1 The flattening thickness and pitch of cold-rolled twisted steel bars shall meet the requirements of Table 1. Engineering Construction Standard Full Text Information System
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Table 1 Flattening thickness, pitch
Marking diameter d
Flattening thickness t
Not less than
Pitch 1
Not greater than
The nominal cross-sectional area and nominal weight of cold-rolled twisted steel bars shall comply with the provisions of Table 2.
Table 2 Nominal cross-sectional area and nominal weight
Marking diameter:
Nominal cross-sectional area A
5.2.3 The allowable deviation of the cut length of cold-rolled twisted steel bars is ±15mm when the length of a single bar is greater than 8m;
When the length of a single bar is not greater than 8m, it is ±10mm. 5.2.4
Weight deviation
Nominal weight G
The negative deviation between the actual weight of cold-rolled twisted steel bars and the nominal weight shall not be greater than 5%5.3 Mechanical properties of cold-rolled twisted steel bars
The mechanical properties of cold-rolled twisted steel bars shall comply with the provisions of Table 3. 5
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Tensile strength
Table 3 Mechanical properties
Elongation 8%0
1 is the mark diameter of cold-rolled twisted steel bars.
Cold bending 180°
(bending center diameter-3a)
No cracks shall occur on the surface of the bending part
2010 is the tensile elongation of the specimen with a gauge length of 10 times the mark diameter. 5.4
Appearance quality of cold-rolled twisted steel bars
The surface of cold-rolled twisted steel bars shall not have cracks, folds, scars, indentations, mechanical damage or other defects that affect the use of steel bars that affect the mechanical properties of steel bars. 5.5 Delivery status
Delivery in cold-processed straight bars.
Test method
Dimension measurement
Measure the flattened thickness at both ends of the sample with a vernier caliper (accuracy 0.02mm). Measure the thickness of the two edges and the middle of the cross section at each end and take the arithmetic average as the thickness of one end. Then take the arithmetic average of the thickness at both ends as the flattened thickness of the cross section of the cold-rolled twisted steel bars. For diamond cross sections, measure the short diagonal dimensions of the cross sections at both ends and take the arithmetic average as the flattened thickness of the diamond cross section.
6.1.2 Pitch Measure the length of not less than 5 full pitches with a ruler (accuracy 1.0mm) and take the average as pitch 1.
The fixed length of cold-rolled twisted steel bars is measured with a steel tape measure (accuracy 1.0mm). 6.2 Weight measurement and deviation
When measuring the weight deviation of cold-rolled twisted steel bars, the length of the sample should not be less than 500mm. The weight deviation is calculated as follows:
Weight deviation (%) =
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-nominal weight, kg/m;
Where: G
G——measured weight, kg,
L—sample length, m.
The test method for chemical composition analysis of raw materials shall comply with the provisions of GB223.69. 6.3
6.4The tensile test of cold-rolled twisted steel bars shall comply with Appendix A (Appendix to the standard). 6.5The cold bending 180° test of cold-rolled twisted steel bars shall comply with the provisions of GB232. Inspection rules
Inspection classification
7.1.1 Factory inspection
The factory inspection of wheel-twisted steel bars is based on the acceptance batch. The inspection items, sampling quantity and test methods should comply with the provisions of Table 4, and the inspection results should be filled in Table B1 of Appendix B (Suggested Appendix).
Table 4 Inspection items, sampling quantity and test methods Inspection itemsbzxZ.net
Appearance quality
Flattened thickness
Fixed length
Chemical composition
Tensile test
Cold bending test
Sampling quantity
Factory inspection
Three per batch
Three per batch
Three per batch
Two per batch
One per batch
Type inspection
Three per batch
Three per batch
Three per batch
Three per batch
Three per batch
Three per batch| |tt||Three in each batch
Three in each batch
Test method
According to 6.1.1 of this standard
According to 6.1.2
According to 6.1.3
According to 6.2
According to 6.3
According to 6.4
According to 6.5
Note: The original gauge length for elongation determination in tensile test is 10αa is the mark diameter of cold-rolled twisted steel bars) 7.1.2 Type inspection
7.1.2.1 The type inspection of cold-rolled twisted steel bars is a comprehensive inspection of the contents specified in the technical requirements of this standard.
7.1.2.2 Type inspection shall be carried out in any of the following cases: 7
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a) Trial production and identification of new products or old products transferred to other factories for production (including technology transfer);
b) After formal production, when there are major changes in materials and processes that may affect product performance;
c) Periodically after the accumulated output of each cold rolling and twisting mill reaches 1,000 tons during normal production;
d) When production is resumed after a long period of suspension;
e) When the factory inspection results are significantly different from those of the last type inspection;
f) When the national quality supervision agency proposes a requirement for type inspection. 7.2 Acceptance batch and sampling rules
Batch rules
The acceptance batch of cold-rolled twisted steel bars shall consist of steel bars of the same brand, same specification size, same rolling mill, and same shift, and each batch shall not be larger than 10t. If less than 10t, it shall be counted as one batch. 7.2.2 The samples of cold-rolled twisted steel bars shall be randomly selected from the acceptance batch of steel bars. The sampling position shall be at least 500mm away from the end of the steel bar. The length of the sample shall be an even multiple of the pitch, and shall not be less than 4 times the pitch, and shall not be less than 500mm. 7.3
Judgment rules
When all the inspection items meet the requirements of this standard, the batch of steel bars shall be judged as qualified. 7.3.2 When the inspection results of one of the inspection items do not meet the requirements of the relevant provisions of this standard, the same batch of steel bars shall be doubled and randomly sampled again, and the unqualified items shall be re-inspected. If the sample is qualified after re-inspection, the batch of steel bars can be judged as qualified. Otherwise, the following rules shall be used for different items.
) When the tensile strength, stretching, cold bending test fails, or the weight negative deviation is greater than 5%, the batch of steel bars is judged as unqualified. b) When only the flattened thickness is less than or the pitch is greater than the requirements of this standard, it can still be judged as qualified, but the diameter specification needs to be reduced for use. For example: the marked diameter is $14 and is reduced to Φ12; Φ12 is reduced to $10, and so on. ? 8
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8 Marking, Labeling, Packaging
8.1 Marking, Labeling
Each bundle of cold-rolled twisted steel bars should be steel bars of the same brand, specification and length. Each bundle should have more than two (including two) labels. The label should be marked with the manufacturer name, product name, specification and length, quantity and production date. 8.2 Packaging
Cold-rolled twisted steel bars shall be delivered in bundles, and each bundle shall be tied with wire at both ends. When the fixed length of the steel bars is greater than 6m, each bundle shall have three tying points. 8.3 Each batch of cold-rolled twisted steel bars shall be accompanied by a quality certificate or a certificate of conformity and a product performance test report before leaving the factory
9 Transportation and storage
9.1 Cold-rolled twisted steel bars shall be transported and loaded and unloaded in bundles, and bending of the steel bars shall be avoided. 9.2
Generally, they should be used as soon as they are processed. They shall be neatly stacked in bundles according to specifications, and the bottom cold-rolled steel bars
layer shall be padded with dry wood, and stored under rainproof conditions. 9
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Appendix A
(Standard Appendix)
Key Points of Tensile Test of Cold-rolled Twisted Steel Bars
A1 Tensile Test
In addition to the relevant provisions of GB228, the following test methods should be adopted to determine the tensile strength and elongation of cold-rolled twisted steel bars. A
Test Method
The test should be carried out on a Class 3 soil testing machine calibrated by the metrology department. The loading rate should not be greater than 2kN/min. A2.2
A2.3For elongation determination, it is recommended to use marking points along the entire length of the specimen (the spacing between marking points is 10 mp). After breaking, select the length between marking points that is symmetrical to the fracture (the number of marking intervals is 10 times the original gauge length) as the gauge length after breaking. A2.4
The sample should be clamped so that the cross-sectional position of the cold-rolled twisted steel bar in the upper and lower clamps remains consistent (as shown in Figure A1)
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a) Trial determination and appraisal of new products or old products for transfer to factory production (including technology transfer):
b) After formal production, when there are major changes in materials and processes that may affect product performance;
c) Periodically after the accumulated output of each cold rolling and twisting mill reaches 1000t in normal production,
d) When production is resumed after a long period of suspension;
e) When the factory inspection results are significantly different from the last type inspection;f) When the national quality supervision agency proposes a type inspection requirement. 7.2 Acceptance batch and sampling rules
Batch rules
The acceptance batch of cold-rolled twisted steel bars shall consist of steel bars of the same brand, same specification size, same rolling mill, and same shift, and each batch shall not exceed 10t, and less than 10t shall be counted as one batch. 7.2.2 The specimens of cold-rolled twisted steel bars shall be randomly selected from the acceptance batch of steel bars. The sampling position should be at least 500mm away from the end of the steel bar. The length of the sample should be an even number of pitches, and should not be less than 4 times the pitch, and at the same time not less than 500mm. 7.3
Judgment rules
When all the inspection items meet the requirements of this standard, the batch of steel bars is judged to be qualified. 7.3.2 When the inspection result of one of the inspection items does not meet the requirements of the relevant provisions of this standard, the batch of steel bars should be doubled and randomly sampled again from the same batch of steel bars, and the unqualified items should be re-inspected. If the recommended sample is qualified after re-inspection, the batch of steel bars can be judged to be qualified. Otherwise, the following rules are used according to different items.
) When the tensile strength, tension, cold bending test is unqualified, or the negative deviation of the weight is greater than 5%, the batch of steel bars is judged to be unqualified. b) When only the flattened thickness is less than or the pitch is greater than the requirements of this standard, it can still be judged to be qualified, but the diameter specification needs to be reduced for use. For example: the marked diameter is $14 and is reduced to Φ12; Φ12 is reduced to $10, and so on. ? 8
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8 Marking, Labeling, Packaging
8.1 Marking, Labeling
Each bundle of cold-rolled twisted steel bars shall be steel bars of the same brand, specification and length. Each bundle shall have two or more (including two) labels. The label shall be marked with the manufacturer's name, product name, specification and length, quantity and production date. 8.2 Packaging
Cold-rolled twisted steel bars shall be delivered in bundles, and each bundle shall be tied with wire at both ends. When the fixed length of the steel bars is greater than 6m, each bundle shall have three tying points. 8.3Each batch of cold-rolled twisted steel bars shall be accompanied by a quality certificate or certificate of conformity and a product performance test report
9 Transportation and Storage
9.1Cold-rolled twisted steel bars shall be transported and loaded and unloaded in bundles, and bending of the steel bars shall be avoided. 9.2
Generally, it is advisable to use it as soon as it is processed. It should be neatly stacked in bundles according to specifications, and the bottom cold-twisted steel bars
layer should be padded with dry wood and stored under rainproof conditions. 9
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Appendix A
(Appendix to the standard)
Key points of tensile test of cold-rolled twisted steel bars
A1 Tensile test
In addition to the relevant provisions of GB228, the following test methods should be used to determine the tensile strength and elongation of cold-rolled twisted steel bars. A
Test method
The test should be carried out on a Class 3 soil testing machine calibrated by the metrology department. The loading rate should not be greater than 2kN/min during the soil test. A2.2
A2.3 For elongation determination, it is recommended to mark the test piece along its entire length (the spacing between the marks is 10 mp). After breaking, select the length between the marks that is symmetrical to the fracture (the number of intervals between the original gauge length and 10 times the gauge diameter) as the gauge length after breaking. A2.4
The clamping of the specimen should keep the cross-section position of the cold-rolled twisted steel bar in the upper and lower clamps consistent (as shown in Figure A1)
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a) Trial determination and appraisal of new products or old products for transfer to factory production (including technology transfer):
b) After formal production, when there are major changes in materials and processes that may affect product performance;
c) Periodically after the accumulated output of each cold rolling and twisting mill reaches 1000t in normal production,
d) When production is resumed after a long period of suspension;
e) When the factory inspection results are significantly different from the last type inspection;f) When the national quality supervision agency proposes a type inspection requirement. 7.2 Acceptance batch and sampling rules
Batch rules
The acceptance batch of cold-rolled twisted steel bars shall consist of steel bars of the same brand, same specification size, same rolling mill, and same shift, and each batch shall not exceed 10t, and less than 10t shall be counted as one batch. 7.2.2 The specimens of cold-rolled twisted steel bars shall be randomly selected from the acceptance batch of steel bars. The sampling position should be at least 500mm away from the end of the steel bar. The length of the sample should be an even number of pitches, and should not be less than 4 times the pitch, and at the same time not less than 500mm. 7.3
Judgment rules
When all the inspection items meet the requirements of this standard, the batch of steel bars is judged to be qualified. 7.3.2 When the inspection result of one of the inspection items does not meet the requirements of the relevant provisions of this standard, the batch of steel bars should be doubled and randomly sampled again from the same batch of steel bars, and the unqualified items should be re-inspected. If the recommended sample is qualified after re-inspection, the batch of steel bars can be judged to be qualified. Otherwise, the following rules are used according to different items.
) When the tensile strength, tension, cold bending test is unqualified, or the negative deviation of the weight is greater than 5%, the batch of steel bars is judged to be unqualified. b) When only the flattened thickness is less than or the pitch is greater than the requirements of this standard, it can still be judged to be qualified, but the diameter specification needs to be reduced for use. For example: the marked diameter is $14 and is reduced to Φ12; Φ12 is reduced to $10, and so on. ? 8
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8 Marking, Labeling, Packaging
8.1 Marking, Labeling
Each bundle of cold-rolled twisted steel bars shall be steel bars of the same brand, specification and length. Each bundle shall have two or more (including two) labels. The label shall be marked with the manufacturer's name, product name, specification and length, quantity and production date. 8.2 Packaging
Cold-rolled twisted steel bars shall be delivered in bundles, and each bundle shall be tied with wire at both ends. When the fixed length of the steel bars is greater than 6m, each bundle shall have three tying points. 8.3Each batch of cold-rolled twisted steel bars shall be accompanied by a quality certificate or certificate of conformity and a product performance test report
9 Transportation and Storage
9.1Cold-rolled twisted steel bars shall be transported and loaded and unloaded in bundles, and bending of the steel bars shall be avoided. 9.2
Generally, it is advisable to use it as soon as it is processed. It should be neatly stacked in bundles according to specifications, and the bottom cold-twisted steel bars
layer should be padded with dry wood and stored under rainproof conditions. 9
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Appendix A
(Appendix to the standard)
Key points of tensile test of cold-rolled twisted steel bars
A1 Tensile test
In addition to the relevant provisions of GB228, the following test methods should be used to determine the tensile strength and elongation of cold-rolled twisted steel bars. A
Test method
The test should be carried out on a Class 3 soil testing machine calibrated by the metrology department. The loading rate should not be greater than 2kN/min during the soil test. A2.2
A2.3 For elongation determination, it is recommended to mark the test piece along its entire length (the spacing between the marks is 10 mp). After breaking, select the length between the marks that is symmetrical to the fracture (the number of intervals between the original gauge length and 10 times the gauge diameter) as the gauge length after breaking. A2.4
The clamping of the specimen should keep the cross-section position of the cold-rolled twisted steel bar in the upper and lower clamps consistent (as shown in Figure A1)
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