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.
This standard was drafted according to the rules specified in GB/T 1.1-2009.
This standard supersedes “Technical Specifications for the Procurement of 43 kg/m~75kg/m As-rolled Rails” (TB/T 2344-2003) and partially supersedes “Technical Specifications for the Heat-treated Rails" (TB/T 2635-2004). Based on TB/T 2344-2003, this standard partially incorporated TB/T 2635-2004, and compared with TB/T 2344-2003, mainly has the following technical changes besides the editorial changes:
- ordering information was added (see Chapter 4);
- requirements of geometric dimensions were modified and supplemented (see 5.1; 4.1 in Edition 2003);
- the straightness requirement was modified (see 5.2, 4.2 in Edition 2003);
- specified length and undergauge rail length were added (see 5.5);
- steel density was modified (see 5.5; 4.4 in Edition 2003);
The requirements of steel designation, chemical composition range and gas content were modified and added (see 6.2; 5.2 in Edition 2003);
- hardness requirements for hot rolled and online heat-treated rails were added (see 6.4);
- the requirement of nonmetallic inclusion was modified (see 6.7; 5.9 in Edition 2003);
- the requirement of surface quality was modified (see 6.10; 5.12 in Edition 2003);
- the requirement of fatigue crack growth was added (see 6.14);
- the requirement of numerical rounding was added (see 8.5).
Attention is drawn to the possibility that some of the contents of this document may be the subject of patent rights. Issue organization of this standard isn't held responsible for identifying any or all such patent rights.
This standard was proposed by and is under the jurisdiction of Standards and Metrology Research Institute of MOR.
Drafting organizations of this standard: Metal and Chemistry Research Institute of China Academy of Railway Sciences, Standards and Metrology Research Institute of MOR, Ansteel Group Co., Ltd., Anshan Iron and Steel Group Corporation, Baotou Iron & Steel Group Co., Ltd., Wuhan Iron and Steel (Group) Corporation, Resident Rail Quality Supervision Centers of Ministry of Railways.
Chief drafting staff of this standard: Zhang Yinhua, Zhou Qingyue, Wang Shuqing, Zhu Mei, Chen Zhaoyang, Liu Fengshou, Zhang Hong, Zuo Yan, Zhi Jianguo, Wu Jinhua, Lv Xuebin, Dong Huali.
PROFESSIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
中华人民共和国铁道行业标准
TB/T 2344-2012
Supersedes TB/T 2344-2003
Partially supersedes TB/T 2635-2004
Technical Specifications for the Procurement of 43 kg/m~75 kg/m Rails
43 kg/m~75 kg/m钢轨订货技术条件
1 Scope
This standard specifies the terms and definitions, ordering information, model dimension and limit deviations, technical requirements, test methods, inspection rules, marking and quality certificate, quality assurance, etc. for 43 kg/m~75 kg/m rails.
This standard is applicable to 43 kg/m~75 kg/m hot-rolled and online heat-treated rails for railway with a maximum running speed of 160 km/h. For heat-treated rails for high speed railway, it may apply.
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 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 223.49 Methods for Chemical Analysis of Iron, Steel and Alloy Extraction Separation - Chlorophosphonazo mA Spectrophotometric Method for the Determination of the Total Rare Earth Content
GB/T 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy - The Perchloric Acid Dehydration Gravimetric Method for the Determination of Silicon Content
GB/T 223.62 Methods for Chemical Analysis of Iron, Steel and Alloy - The Butyl Acetate Extraction Photometric Method for the Determination of Phosphorus Content
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 223.68 Methods for Chemical Analysis of Iron, Steel and Alloy - The Potassium Iodate Titration Method after Combustion in the Pipe Furnace for the Determination of Sulfur Content
GB/T 223.71 Methods for Chemical Analysis of Iron, Steel and Alloy - The Gravimetric Method after Combustion in the Pipe Furnace for the Determination of Carbon Content
GB/T 223.82 Steel and Iron - Determination of Hydrogen Content - Inert Gas Impulse Fusion Heat Conductivity Method
GB/T 226 Etch Test for Macrostructure and Defect of Steels
GB/T 228.1 Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature"
GB/T 230.1 Metallic Materials - Rockwell Hardness Test Part 1: Test Method
GB/T 231.1 Metallic Materials - Brinell Hardness Test - Part 1: Test Method
GB/T 3075 Metallic Materials - Fatigue Testing - Axial-force-controlled Method
GB/T 4161 Plane strain Fracture Toughness KIC Test Method for Metal Material
GB/T 4336 Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)
GB/T 4340.1 Metallic Materials-Vickers Hardness Test - Part 1: Test Method
GB/T 6398. STANDARD Test Method for Fatigue Crack Growth Rates of Metallic Materials
GB/T 10561-2005 Steel Determination of Content of Nonmetallic Inclusions Micrographic Method Using Standards Diagrams
GB/T 11261 Steel and Iron - Determination of Oxygen Content - The Pulse Heating Inert Gas Fusion-Infra-red Absorption Method
GB/T 13298 Metal-Inspection Method of Microstructure
GB/T 19001 Quality Management Systems 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
YB/T 081 Rule for Rounding off of Numerical Values and Judgment of Testing Values for Technical Standards of Metallurgy
YB/T 951 Method of the Ultrasonic Inspection for Rails
3 Terms and Definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
Heat
All the blanks casted with one heat, excluding the first blank casted with the next heat entering into the tundish
3.2
Sequence
Continuous casting of different heats of the same designation in tundish
3.3
Transition area
Parts casted by two heats
3.4
Online heat-treatment
Heat treatment by which fine lamellar pearlite structures are obtained by direct accelerated cooling with the residual heat of rolling.
4 Ordering Information
The user shall provide the following basic information for order:
a) product name;
b) product standard reference;
c) rail model;
d) steel designation and delivery condition;
e) machined condition of rail end (bore number at one or both ends, and with rail end heat treated or not);
f) length, quantity and undergauge rate;
g) other requirements.
5 Model Dimension, Length, Weight and Limit Deviations
5.1 Model Dimension and Limit Deviations
5.1.1 The model dimensions of rail profile shall meet the requirements of Appendix A.
5.1.2 The dimensional limit deviations of rail profile, end face, length and bolthole shall be in accordance with those specified in Table 1.
5.2 Straightness and Distortion
The rail straightness and distortion shall meet those specified in Table 2.
Table 1 Dimensional Limit Deviations Unit: mm
Item Limit deviation Template drawing a
43 kg/m 50 kg/m, 60 kg/m, 75 kg/m
Rail height (H) ±0.6 ±0.6 Figure B.3
Railhead width (WH) ±0.5 ±0.5 Figure B.4
Crest plumpness b(C) +0.6
-0.5 Figure B.5
Profile asymmetry (AB) ±1.5 ±1.2 Figure B.6
Inclination of joint bar mounting face (with reference to the inclination of the 14 mm length parallel to the theoretical bevel of joint bar) (IF) ±0.50 ±0.50 Figure B.7
Height of joint bar mounting face (HF) +0.6
-0.5 +0.6
-0.5 Figure B.7
Web thickness (WT) +1.0
-0.5 +1.0
-0.5 Figure B.8
Foot width (WF) +1.0
-1.5 +1.0
-1.5 Figure B.9
Foot edge thickness (TF) +0.75
-0.5 Figure B.10
Fo recess ≤0.4 ≤0.4
End face inclination (vertical and horizontal) ≤0.8 ≤0.8
Bolthole diameter ±0.8 ±0.8 Figure B.11
Bolthole position ±0.8 ±0.8 Figure B.12
Integrated deviation of bolthole diameter and position(Td/c) 2.0 2.0
Length (20ºC) Welded rail ≤25 m rail ±10
>25 m rail ±30
Holed rail ≤25 m rail
±6
a See Appendix B for the template drawing for geometric dimension check of rail.
b No requirement of crest plumpness for 50 kg/m rails.
5.3 Bolthole
No bolthole is machined for welded rails. The boltholes, where required, shall be indicated in the contract. The bolthole edge of rail shall be chamfered to 0.8 mm~1.5 mm and 45°.
5.4 Rail End Chamfering
The part of holed rail from the rail end/head to the lower rounding shall be chamfered as specified in Appendix A.
Table 2 Straightness and Distortion
Position Item Tolerance
0-1.5 m from rail end Straightness a Vertical b, c (upward) ≤0.6 mm/1.5 m
Vertical b, c (downward) d ≤0.2 mm/1.5 m
Horizontal b, c ≤0.7 mm/1.5 m
1 m-2.5 m from rail end Straightness a Vertical ≤0.5 mm/1.5m
Horizontal ≤0.7 mm/1.5 m
Rail body e Straightness a Vertical ≤0.5 mm/3 m, ≤0.4 mm/1.5 m
Horizontal ≤0.6 mm/1.5 m
Full length of rail Up bending and down bending f ≤10 mm
Lateral bending Bending radius R>1 500 m
Distortion Full length g ≤2.5 mm
Rail end h, i ≤0.6 mm/1 m
a Straightness measurement shall avoid repaired or polished position.
b See Figure 1 for rail straightness measurement, where, L is the length of measuring ruler, d and e are allowable tolerances.
c The measurement position for vertical straightness is the railhead tread center and that for horizontal straightness is 5 mm~10 mm below the railhead side arc.
d The length with head drop (F) shall not be less than 0.6 m, as shown in Figure 1.
e The part of rail body other than 0~1.5 m of rail end.
f When rail stands upright on the test rig, the up bend at end shall not exceed 10 mm.
g If visible distortion can be detected when the rail is vertically placed on the test rig with railhead upward, the gap between the foot plane at rail end and test rig plane measured with feeler gauge shall not exceed 2.5 mm.
h The relative distortion between rail end and the cross section 1 m away shall not exceed 0.6 mm. Taking the rail end section as the measuring datum, measure the contacts on the foot lower surface with special gauge (1m long distortion gauge), with the contact center 10 mm from the foot edge and contact area of contacts 150 mm2~250 mm2, as shown in Figure 2.
i Rail end distortion inspection is not required for 43 kg/m rails, 50 kg/m, 60 kg/m and 75 kg/m holed rails.
Figure 1 Schematic Diagram for Rail Straightness Measurement
Dimensions in millimeters
Key:
1- cross section 1 m from rail end face;
2- guage (distortion gauge);
3- cross section of rail end;
When b≥150 mm, c=130 mm; when 130 mm≤b<150 mm, c=110 mm.
Figure 2 Schematic Diagram for Rail End Distortion Measurement
5.5 Length and Weight
5.5.1 Specified length of standard rail:
a) 43 kg/m rail: 12.5 m, 25 m;
b) 50 kg/m, 60 kg/m rail: 12.5 m, 25 m, 100 m;
c) 75 kg/m rail: 25 m, 75 m, 100 m.
5.5.2 Length of reduced curve rail:
a) 12.5 m rail: 12.46 m, 12.42m, 12.38 m;
b) 25 m rail: 24.96 m, 24.92 m, 24.84 m.
5.5.3 Length of undergauge rail:
a) 12.5 m rail: 9 m, 9.5 m, 11 m, 11.5 m, 12 m;
b) 25 m rail: 21 m, 22 m, 23 m, 24 m, 24.5 m;
c) 75 m rail: 71 m, 72 m, 73 m, 74 m;
d) 100 m rail: 95 m, 96 m, 97 m and 99 m.
5.5.4 For reduced curve rails of 75 m and 100 m specified length, rails of the other specified lengths and undergauge rails, the length shall be agreed by the supplier and demander and specified in the contract.
5.5.5 The matching quantity of undergauge rails shall be agreed by the supplier and demander and specified in the contract, which shall not be greater than 10% of the total weight of the order batch. For holed rails, there shall be no undergauge rails.
5.5.6 Rails shall be delivered as per theoretical mass. The steel density is 7.85 g/cm3. See Appendix A for the theoretical masses of rails.
6 Technical Requirements
6.1 Manufacturing Method
6.1.1 Rail steel shall be smelted with basic oxygen furnace or electric arc furnace and treated through external refining and vacuum degassing.
6.1.2 Steel rails shall be manufactured by continuous casting.
6.1.3 Steel rails in rolling process shall be so descaled by multi-stage high-pressure spraying as to remove scaling effectively.
6.1.4 The rolling reduction of rails shall not be less than 9:1.
6.1.5 Steel rails shall straightened respectively along the horizontal axis X-X and vertical axis Y-Y of its section with two-section roller straightener and only one roll straightening is permitted. Any end or partial unflatness may be additionally straightened with four-side press. Holed rails shall be additionally straightened before hole drilling.
6.1.6 Welded rails do not need to have their ends heat-treated; U71Mn hot-rolled holed rails shall undergo end heat treatment, which, if not required, shall be specified in the contract; hot-rolled holed rails of other designations do not need to have their ends heat-treated.
6.2 Designation and Chemical Composition
6.2.1 The designation, chemical composition and residual elements (melting analysis) of steels shall meet those specified in Table 3 and Table 4. Residual element inspection may be omitted if it is guaranteed by the supplier.
Amendment 1 I
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Ordering Information
5 Model Dimension, Length, Weight and Limit Deviations
5.1 Model Dimension and Limit Deviations
5.2 Straightness and Distortion
5.3 Bolthole
5.4 Rail End Chamfering
5.5 Length and Weight
6 Technical Requirements
6.1 Manufacturing Method
6.2 Designation and Chemical Composition
6.3 Tensile Property
6.4 Hardness
6.5 Microstructure
6.6 Decarburized Layer
6.7 Nonmetallic Inclusion
6.8 Macrostructure
6.9 Drop Weight
6.10 Surface Quality
6.11 Ultrasonic Testing
6.12 Residual Stress of Foot
6.13 Fracture Toughness
6.14 Fatigue Crack Growth
6.15 Fatigue
6.16 Heat Treatment of Rail End
7 Test Method
7.1 Inspection Item, Inspection Frequency, Sampling Position and Test Method
7.2 Hydrogen Content
7.3 Total Oxygen Content and Nitrogen Content
7.4 Hardness
7.5 Microstructure
7.6 Drop weight
7.7 Ultrasonic Testing
7.8 Residual Stress at Rail Root
7.9 Fracture Toughness
7.10 Fatigue Crack Growth
7.11 Fatigue
8 Inspection Rules
8.1 Supervision
8.2 Type Inspection
8.3 Delivery Inspection
8.4 Re-inspection and Judgment
8.5 Numerical Rounding
9 Mark and Quality Certificate
9.1 Mark
9.2 Quality Certification
10 Quality Assurance
10.1 Quality Assurance System
10.2 Quality Guarantee Period
Appendix A (Normative) Type and Dimension of 43kg/m ~ 75kg/m Rails
Appendix B (Normative) Schematic Diagram for the Geometric Dimension Inspection Template of Rail
Appendix C (Normative) Unallowable Defects on the Transversal Acid Leached Test Plate of Rail
Appendix D (Normative) Test Method for Rail Plane Strain Fracture Toughness KIC
Appendix E (Normative) Heat-Treatment Technical Conditions for Rail End
Appendix F (Normative) Measured Method for Longitudinal Residual Stress of Foot
