Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 1499 consists of the following four parts under the general title Steel for the Reinforcement of Concrete:
— 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 is drafted in accordance with the rules given in the GB/T 1.1-2009.
This part replaces GB 1499.2-2007 Steel for the Reinforcement of Concrete — Part 2: Hot Rolled Ribbed Bars in whole.
The following technical deviations have been made with respect to the GB/T 1499.22007 (the previous edition):
— addition of the smelting method;
— cancellation of the 335 MPa steel bars;
— addition of the 600 MPa steel bars;
— addition of the designation with letter E;
— properly and strictly specifies the permissible deviation and bending of length;
— properly and strictly specifies the permissible weight deviation, and make clear that the weight deviation is not allowed to repeat inspection;
— change of the backward bending test of steel bar designation with letter E as a routine inspection item;
— addition of the requirements on fatigue test method of steel bars;
— addition of the requirements on metallographic test;
— addition of the macroscopic metallography, vickers hardness of cross-section, microstructure and testing methods;
— addition of the measuring method for the end clearance of the transverse ribs;
— replacement of the surface marking with the “registered manufacturer’s name (or trademark)” and “the production license number (the last 3 digits) of the hot rolled ribbed bars the reinforcement of concrete obtained by the enterprise”, and deletion of the “steel bars with nominal diameter of no more than 10 mm may not be rolled, but the method of hanging the sign";
— deletion of Annex A Methods for Measuring the Total Elongation of Steel Bars under the Maximum Force.
This part has been redrafted adoption of ISO 6935-2: 2015 Steel for the Reinforcement of Concrete — Part 2: Ribbed Bars, which is not equivalent to ISO 6935-2: 2015 in consistency.
This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions replaced by this part are as follows:
— GB 1499-1979, GB 1499-1984, GB 1499-1991, GB 1499-1998;
— GB/T 1499.2-2007.
Steel for the Reinforcement of Concrete — Part 2: Hot Rolled Ribbed Bars
1 Scope
This standard specifies the terms and definitions, classification, designation, order contents, dimension, shape, weight and permissible deviation, 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 ribbed bars).
This part is applicable to ordinary hot-rolled ribbed bars and fine-grained hot-rolled ribbed bars for the reinforcement of concrete.
This part is not applicable to regenerated ribbed bars and residual heat-treated ribbed bars produced from finished 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 Deviations 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 Neocuproine-Chloroform Extraction Photometric Method for the Determination of Copper Content
GB/T 223.23 Methods for Chemical Analysis of Iron, Steel and Alloy — The Dimethylglyoxime Spectrophotometric Method
GB/T 223.26 Iron Steel and Alloy — Determination of Molybdenum Content — The Thiocyanate Spectrophotometric Method
GB/T 223.37 Methods for Chemical Analysis of Iron, Steel and Alloy — Indophenol Blue Photometric Method for the Determination of Nitrogen Content after Distillation Separation
GB/T 223.40 Iron Steel and Alloy — Determination of Molybdenum Content by the Sulphochlorophenol S Spectrophotometric Method
GB/T 223.59 Iron Steel and Alloy — Determination of Molybdenum Content — Bismuth Phosphomolybdate Blue Spectrophotometric Method and Antimony Phosphomolybdate Blue Spectrophotometric Method
GB/T 223.63 Methods for Chemical Analysis of Iron, Steel and Alloy — The Sodium (Potassium) Periodate Photometric Method for the Determination of Manganese Content
GB/T 223.85 Steel and Iron — Determination of Sulfur Content — Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 223.86 Steel and Iron — Determination of Total Carbon Content - Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 2101 General Requirement of Acceptance Packaging, Marking and Certification for Section Steel
GB/T 4336 Carbon and Low-alloy Steel — Determination of Multi-element Contents — Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
GB/T 4340.1 Metallic Materials — Vickers Hardness Test — Part 1: Test Method
GB/T 6394 Determination of Estimating the Average Grain Size of Metal
GB/T 13298 Inspection Methods of Microstructure for Metals
GB/T 17505 Steel and Steel Products — General Technical Delivery Requirements
GB/T 20066 Steel and Iron — Sampling and Preparation of Samples for the Determination of Chemical Composition
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 Numberical Values and Judgement of Testing Values for Technical Standards of Metallurgy
JGJ 18 Specification for Welding and Acceptance of Reinforcing Steel Bars
JGJ 107 General Technical Specification for Mechanical Splicing of Bars
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
hot rolled bars
ribbed bars delivered in hot rolled condition
3.2
hot rolled bars of fine grains
in the hot rolling process, the fine grain ribbed bars formed by the controlled rolling and controlled cooling processes have a particle size of 9 or less
3.3
ribbed bars
ribbed bars with a generally circular cross section and a ribbed surface for the reinforcement of concrete
3.4
longitudinal rib
uniform continuous rib parallel to the axis of the bar
3.5
transverse rib
other ribs that are not parallel to the axis of the bar
3.6
crescent ribbed bars
the longitudinal section of the transverse rib is crescent-shaped and does not intersect the longitudinal ribs
3.7
nominal diameter
the diameter of a circle equal to the nominal cross-sectional area of the bar.
3.8
specific projected rib area
the ratio of projected area of the rib on the plane vertical to the ribbed bar axes to the product of nominal perimeter and rib spacing.
3.9
rib height
distance from the highest point on the rib to the surface of the core, to be measured perpendicular to the axis of the bar
3.10
rib spacing
distance between the centres of two consecutive transverse ribs measured parallel to the axis of the bar
3.11
characteristic value
value having a prescribed probability of not being attained in a hypothetical unlimited test series
3.12
core
part of the cross-section of the bar not containing either longitudinal or transverse ribs
4 Classification and Designation
4.1 Ribbed bars are classified into 400, 500, and 600 grades according to the yield strength characteristic values.
4.2 The composition of the ribbed bar designation and its meaning are shown in Table 1.
Table 1
Category Designation Structure of designation English letter meaning
Hot rolled bar HRB400 Consisting of HRB+ yield strength characteristic values HRB — the abbreviation of Hot rolled Ribbed Bars.
E — The first letter of the “Earthquake”
HRB500
HRB600
HRB400E Consisting of HRB+ yield strength characteristic values + E
HRB500E
Hot rolled bar of fine grains HRBF400 Consisting of HRBF+ yield strength
characteristic values HRBF — addition of the first letter of "fine” after the English abbreviation of hot-rolled ribbed bar.
E — The first letter of the “Earthquake”
HRBF500
HRBF400E Consisting of HRBF+ yield strength
characteristic values + E
HRBF500E
5 Order Contents
Contracts for orders under this part shall at least include the following information:
a) the number of this part;
b) product name;
c) ribbed bar designation;
d) nominal diameter, length and weight (or quantity, or coil weight) of the ribbed bar;
e) special requirements.
6 Dimension, Shape, Weight and Tolerance
6.1 Nominal diameter range
The nominal diameter range of ribbed bar is 6 mm to 50 mm.
6.2 Nominal cross section area and theoretical weight
The nominal cross section area and theoretical weight of ribbed bars as shown in Table 2.
Table 2
Nominal diameter
mm Nominal section area
mm2 Theoretical weight a
kg/m
The theoretical weight is calculated as a density of 7.85 g/cm3.
6.3 Surface shape and dimension tolerance of ribbed bars
6.3.1 The design principle of transverse ribs of ribbed bars shall comply with the following requirements:
a) the angle β between the transverse rib and the axis of the ribbed bar shall be not less than 45°. When the angle β is not more than 70°, the direction of the transverse ribs of the reinforcing bars on opposite sides should be opposite.
b) the nominal spacing of the transverse ribs shall not be greater than 0.7 times the nominal diameter of the ribbed bars.
c) the angle α between both sides of the rib and the bar surface shall not be less than 45°.
d) the sum of the end clearance between the transverse ribs on the adjacent two sides of the ribbed bar (including the longitudinal rib width) shall not be greater than 20% of the nominal circumference of the ribbed bar.
e) when the nominal diameter of the ribbed bar is not more than 12 mm, the specific projected rib area is not less than 0.055; when the nominal diameter is 14 mm and 16 mm, the specific projected rib area is not less than 0.060; when the nominal diameter is larger than 16 mm, the specific projected rib area is not less than 0.065. Refer to Annex A for the calculation of the specific projected rib area.
6.3.2 Ribbed bars usually have longitudinal ribs or no longitudinal ribs. The shape of crescent ribbed bars with longitudinal ribs as shown in Figure 1. The dimensions and tolerances shall be in accordance with Table 3.
6.3.3 The deviation between the actual weight of the ribbed bar and the theoretical weight shall be in accordance with Table 4. The deviation of the inner diameter of the ribbed bar is not subject to delivery conditions.
6.3.4 For crescent ribbed bars without longitudinal ribs, the inner diameter of the bars may be adjusted as specified in Table 3, but the weight deviation shall still comply with the requirements of Table 4.
Foreword II
1 Scope
2 Normative References
3 Terms and Definitions
4 Classification and Designation
5 Order Contents
6 Dimension, Shape, Weight and Tolerance
6.1 Nominal diameter range
6.2 Nominal cross section area and theoretical weight
6.4 Length and permissible deviation
6.5 Curvature and end
6.6 Weight and permissible deviation
7 Technical Requirements
7.1 Smelting process
7.2 Designations and chemical compositions
7.3 Delivery type
7.4 Mechanical properties
7.5 Processing properties
7.6 Fatigue properties
7.7 Connection properties
7.8 Grain size
7.9 Metallographic structure
7.10 Surface quality
8 Test Methods
8.1 Test items
8.2 Tensile, bending and reverse bending tests
8.3 Dimensional measurement
8.4 Measurement of weight deviation
8.5 Macroscopic metallography, vickers hardness of cross-section, microstructure tests
8.6 Rounding off of numerical values
9 Inspection Rules
9.1 Inspection classification
9.2 Characteristic value inspection
9.3 Delivery inspection
10 Packaging, Marking and Quality Certificate
Annex A (Informative) Formula for Calculating the Specific Projected Rib Area of Ribbed Bars
Annex B (Normative) Macroscopic Metallography, Vickers Hardness of Cross-section, Microstructure and Test Methods of Ribbed Bars
Annex C (Normative) Inspection Rules for Characteristic Value
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 1499 consists of the following four parts under the general title Steel for the Reinforcement of Concrete:
— 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 is drafted in accordance with the rules given in the GB/T 1.1-2009.
This part replaces GB 1499.2-2007 Steel for the Reinforcement of Concrete — Part 2: Hot Rolled Ribbed Bars in whole.
The following technical deviations have been made with respect to the GB/T 1499.22007 (the previous edition):
— addition of the smelting method;
— cancellation of the 335 MPa steel bars;
— addition of the 600 MPa steel bars;
— addition of the designation with letter E;
— properly and strictly specifies the permissible deviation and bending of length;
— properly and strictly specifies the permissible weight deviation, and make clear that the weight deviation is not allowed to repeat inspection;
— change of the backward bending test of steel bar designation with letter E as a routine inspection item;
— addition of the requirements on fatigue test method of steel bars;
— addition of the requirements on metallographic test;
— addition of the macroscopic metallography, vickers hardness of cross-section, microstructure and testing methods;
— addition of the measuring method for the end clearance of the transverse ribs;
— replacement of the surface marking with the “registered manufacturer’s name (or trademark)” and “the production license number (the last 3 digits) of the hot rolled ribbed bars the reinforcement of concrete obtained by the enterprise”, and deletion of the “steel bars with nominal diameter of no more than 10 mm may not be rolled, but the method of hanging the sign";
— deletion of Annex A Methods for Measuring the Total Elongation of Steel Bars under the Maximum Force.
This part has been redrafted adoption of ISO 6935-2: 2015 Steel for the Reinforcement of Concrete — Part 2: Ribbed Bars, which is not equivalent to ISO 6935-2: 2015 in consistency.
This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions replaced by this part are as follows:
— GB 1499-1979, GB 1499-1984, GB 1499-1991, GB 1499-1998;
— GB/T 1499.2-2007.
Steel for the Reinforcement of Concrete — Part 2: Hot Rolled Ribbed Bars
1 Scope
This standard specifies the terms and definitions, classification, designation, order contents, dimension, shape, weight and permissible deviation, 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 ribbed bars).
This part is applicable to ordinary hot-rolled ribbed bars and fine-grained hot-rolled ribbed bars for the reinforcement of concrete.
This part is not applicable to regenerated ribbed bars and residual heat-treated ribbed bars produced from finished 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 Deviations 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 Neocuproine-Chloroform Extraction Photometric Method for the Determination of Copper Content
GB/T 223.23 Methods for Chemical Analysis of Iron, Steel and Alloy — The Dimethylglyoxime Spectrophotometric Method
GB/T 223.26 Iron Steel and Alloy — Determination of Molybdenum Content — The Thiocyanate Spectrophotometric Method
GB/T 223.37 Methods for Chemical Analysis of Iron, Steel and Alloy — Indophenol Blue Photometric Method for the Determination of Nitrogen Content after Distillation Separation
GB/T 223.40 Iron Steel and Alloy — Determination of Molybdenum Content by the Sulphochlorophenol S Spectrophotometric Method
GB/T 223.59 Iron Steel and Alloy — Determination of Molybdenum Content — Bismuth Phosphomolybdate Blue Spectrophotometric Method and Antimony Phosphomolybdate Blue Spectrophotometric Method
GB/T 223.63 Methods for Chemical Analysis of Iron, Steel and Alloy — The Sodium (Potassium) Periodate Photometric Method for the Determination of Manganese Content
GB/T 223.85 Steel and Iron — Determination of Sulfur Content — Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 223.86 Steel and Iron — Determination of Total Carbon Content - Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 2101 General Requirement of Acceptance Packaging, Marking and Certification for Section Steel
GB/T 4336 Carbon and Low-alloy Steel — Determination of Multi-element Contents — Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
GB/T 4340.1 Metallic Materials — Vickers Hardness Test — Part 1: Test Method
GB/T 6394 Determination of Estimating the Average Grain Size of Metal
GB/T 13298 Inspection Methods of Microstructure for Metals
GB/T 17505 Steel and Steel Products — General Technical Delivery Requirements
GB/T 20066 Steel and Iron — Sampling and Preparation of Samples for the Determination of Chemical Composition
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 Numberical Values and Judgement of Testing Values for Technical Standards of Metallurgy
JGJ 18 Specification for Welding and Acceptance of Reinforcing Steel Bars
JGJ 107 General Technical Specification for Mechanical Splicing of Bars
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
hot rolled bars
ribbed bars delivered in hot rolled condition
3.2
hot rolled bars of fine grains
in the hot rolling process, the fine grain ribbed bars formed by the controlled rolling and controlled cooling processes have a particle size of 9 or less
3.3
ribbed bars
ribbed bars with a generally circular cross section and a ribbed surface for the reinforcement of concrete
3.4
longitudinal rib
uniform continuous rib parallel to the axis of the bar
3.5
transverse rib
other ribs that are not parallel to the axis of the bar
3.6
crescent ribbed bars
the longitudinal section of the transverse rib is crescent-shaped and does not intersect the longitudinal ribs
3.7
nominal diameter
the diameter of a circle equal to the nominal cross-sectional area of the bar.
3.8
specific projected rib area
the ratio of projected area of the rib on the plane vertical to the ribbed bar axes to the product of nominal perimeter and rib spacing.
3.9
rib height
distance from the highest point on the rib to the surface of the core, to be measured perpendicular to the axis of the bar
3.10
rib spacing
distance between the centres of two consecutive transverse ribs measured parallel to the axis of the bar
3.11
characteristic value
value having a prescribed probability of not being attained in a hypothetical unlimited test series
3.12
core
part of the cross-section of the bar not containing either longitudinal or transverse ribs
4 Classification and Designation
4.1 Ribbed bars are classified into 400, 500, and 600 grades according to the yield strength characteristic values.
4.2 The composition of the ribbed bar designation and its meaning are shown in Table 1.
Table 1
Category Designation Structure of designation English letter meaning
Hot rolled bar HRB400 Consisting of HRB+ yield strength characteristic values HRB — the abbreviation of Hot rolled Ribbed Bars.
E — The first letter of the “Earthquake”
HRB500
HRB600
HRB400E Consisting of HRB+ yield strength characteristic values + E
HRB500E
Hot rolled bar of fine grains HRBF400 Consisting of HRBF+ yield strength
characteristic values HRBF — addition of the first letter of "fine” after the English abbreviation of hot-rolled ribbed bar.
E — The first letter of the “Earthquake”
HRBF500
HRBF400E Consisting of HRBF+ yield strength
characteristic values + E
HRBF500E
5 Order Contents
Contracts for orders under this part shall at least include the following information:
a) the number of this part;
b) product name;
c) ribbed bar designation;
d) nominal diameter, length and weight (or quantity, or coil weight) of the ribbed bar;
e) special requirements.
6 Dimension, Shape, Weight and Tolerance
6.1 Nominal diameter range
The nominal diameter range of ribbed bar is 6 mm to 50 mm.
6.2 Nominal cross section area and theoretical weight
The nominal cross section area and theoretical weight of ribbed bars as shown in Table 2.
Table 2
Nominal diameter
mm Nominal section area
mm2 Theoretical weight a
kg/m
The theoretical weight is calculated as a density of 7.85 g/cm3.
6.3 Surface shape and dimension tolerance of ribbed bars
6.3.1 The design principle of transverse ribs of ribbed bars shall comply with the following requirements:
a) the angle β between the transverse rib and the axis of the ribbed bar shall be not less than 45°. When the angle β is not more than 70°, the direction of the transverse ribs of the reinforcing bars on opposite sides should be opposite.
b) the nominal spacing of the transverse ribs shall not be greater than 0.7 times the nominal diameter of the ribbed bars.
c) the angle α between both sides of the rib and the bar surface shall not be less than 45°.
d) the sum of the end clearance between the transverse ribs on the adjacent two sides of the ribbed bar (including the longitudinal rib width) shall not be greater than 20% of the nominal circumference of the ribbed bar.
e) when the nominal diameter of the ribbed bar is not more than 12 mm, the specific projected rib area is not less than 0.055; when the nominal diameter is 14 mm and 16 mm, the specific projected rib area is not less than 0.060; when the nominal diameter is larger than 16 mm, the specific projected rib area is not less than 0.065. Refer to Annex A for the calculation of the specific projected rib area.
6.3.2 Ribbed bars usually have longitudinal ribs or no longitudinal ribs. The shape of crescent ribbed bars with longitudinal ribs as shown in Figure 1. The dimensions and tolerances shall be in accordance with Table 3.
6.3.3 The deviation between the actual weight of the ribbed bar and the theoretical weight shall be in accordance with Table 4. The deviation of the inner diameter of the ribbed bar is not subject to delivery conditions.
6.3.4 For crescent ribbed bars without longitudinal ribs, the inner diameter of the bars may be adjusted as specified in Table 3, but the weight deviation shall still comply with the requirements of Table 4.
Contents of GB/T 1499.2-2018
Foreword II
1 Scope
2 Normative References
3 Terms and Definitions
4 Classification and Designation
5 Order Contents
6 Dimension, Shape, Weight and Tolerance
6.1 Nominal diameter range
6.2 Nominal cross section area and theoretical weight
6.4 Length and permissible deviation
6.5 Curvature and end
6.6 Weight and permissible deviation
7 Technical Requirements
7.1 Smelting process
7.2 Designations and chemical compositions
7.3 Delivery type
7.4 Mechanical properties
7.5 Processing properties
7.6 Fatigue properties
7.7 Connection properties
7.8 Grain size
7.9 Metallographic structure
7.10 Surface quality
8 Test Methods
8.1 Test items
8.2 Tensile, bending and reverse bending tests
8.3 Dimensional measurement
8.4 Measurement of weight deviation
8.5 Macroscopic metallography, vickers hardness of cross-section, microstructure tests
8.6 Rounding off of numerical values
9 Inspection Rules
9.1 Inspection classification
9.2 Characteristic value inspection
9.3 Delivery inspection
10 Packaging, Marking and Quality Certificate
Annex A (Informative) Formula for Calculating the Specific Projected Rib Area of Ribbed Bars
Annex B (Normative) Macroscopic Metallography, Vickers Hardness of Cross-section, Microstructure and Test Methods of Ribbed Bars
Annex C (Normative) Inspection Rules for Characteristic Value
