TB/T 2344.1-2020 (TB/T 2344-2012) PDF EnglishUS$190.00 · In stock · Download in 9 seconds
TB/T 2344-2012: [Including 2017XG1] Technical specifications for the procurement of 43 kg/m~75 kg/m rails Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Obsolete TB/T 2344: Historical versions
Similar standardsTB/T 2344-2012: [Including 2017XG1] Technical specifications for the procurement of 43 kg/m~75 kg/m rails---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/TBT2344-2012 RAILWAY INDUSTRY STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 45.080 S 11 Replacing TB/T 2344-2003, partial replacing TB/T 2635-2004 Technical Specifications for the Procurement of 43kg/m ~ 75kg/m Rails [Including Amendment No.1 [2017XG1]] Issued on: MARCH 01, 2012 Implemented on: JULY 01, 2012 Issued by. Ministry of Railways of PRC Table of ContentsForeword... 5 1 Scope... 7 2 Normative References... 7 3 Terms and Definitions... 9 4 Ordering Required Information... 9 5 Type Size, Length, Weight and Limit Deviation... 10 5.1 Type size and limit deviation... 10 5.2 Straightness and distortion... 10 5.3 Bolt hole... 11 5.4 Rail end chamfering... 11 5.5 Length and weight... 13 6 Technical Requirements... 14 6.1 Manufacturing method... 14 6.2 Designation and chemical composition... 14 6.3 Tensile properties... 16 6.4 Hardness... 16 6.5 Microstructure... 17 6.6 Decarburization layer... 17 6.7 Non-metallic inclusions... 18 6.8 Macrostructure... 19 6.9 Drop-Weight... 19 6.10 Surface quality... 19 6.11 Ultrasonic flaw detection... 20 6.12 Residual stress on rail base... 21 6.13 Fracture toughness... 21 6.14 Fatigue crack growth rate... 21 6.15 Fatigue... 21 6.16 Heat treatment on the rail end... 21 7 Test Methods... 21 7.1 Inspection items, inspection frequency, sampling positions and test methods ... 21 7.2 Hydrogen content... 24 7.3 Total oxygen content and nitrogen content... 24 7.4 Hardness... 25 7.5 Microstructure... 25 7.6 Drop-weight... 25 7.7 Ultrasonic flaw detection... 26 7.8 Residual stress on the rail base... 29 7.9 Fracture toughness... 29 7.10 Fatigue crack growth rate... 29 7.11 Fatigue... 30 8 Inspection Rules... 32 8.1 Supervision... 32 8.2 Type inspection... 32 8.3 Exit-factory inspection... 32 8.4 Reinspection and judgment... 33 8.5 Numerical rounding off... 34 9 Marking, Quality Certificate... 35 9.1 Marking... 35 9.2 Quality certificate... 36 10 Quality Assurance... 36 10.1 Quality assurance system... 36 10.2 Quality assurance period... 36 Appendix A (Normative) 43kg/m ~ 75kg/m Rail Type and Size... 38 Appendix B (Normative) Schematic Diagram of Rail Geometry Inspection Template... 45 Appendix C (Normative) Impermissible Defects on Rail Lateral Acid Leaching Test Strips... 54 Appendix D (Normative) Rail Plane Strain Fracture Toughness KIC Test Method ... 61 Appendix E (Normative) Heat Treatment Technical Condition on the End of Rail ... 65 Appendix F (Normative) Method for Measuring Longitudinal Residual Stress of Rail Base Surface... 68 Bibliography... 70 Amendment No.1 [2017XG1] TB/T 2344-2012 Technical Specification for the Procurement of 43kg/m ~ 75kg/m Rails... 71 Technical Specifications for the Procurement of 43kg/m ~ 75kg/m Rails1 ScopeThis Standard specifies the terms and definitions, ordering required information, type size and limit deviation, technical requirements, test methods, inspection rules, marking and quality certificate, quality assurance, and the like contents of 43kg/m ~ 75kg/m rails. This Standard is applicable to the 43kg/m ~ 75kg/m hot-rolled and online heat-treated rails for the railway with the maximum running speed of 160km/h. this Standard can be referred by the heat-treated rails for high-speed railways.2 Normative ReferencesThe following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document. 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 Test Method for Macrostructure and Defect of Steel By Etching 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 Metallic Materials - Determination of Plane-Strain Fracture Toughness – KIC test 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 Metallic Materials - Fatigue Testing - Fatigue Crack Growth Method 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 (Routine Method) YB/T 081 Rule for Rounding off of Numerical Values and Judgement of Testing Values for Technical Standards of Metallurgy YB/T 951 Method of the Ultrasonic Inspection for Rails3 Terms and DefinitionsFor the purpose of this document, the following terms and definitions apply. 3.1 Heat All casting billets from the molten steel in one furnace; but excluding the first casting billet cast into the tundish from the molten steel in the next furnace. 3.2 Sequence The molten steel with the same designation and different heats is continuously cast in the tundish. 3.3 Transition area The part cast by mixing of the molten steels in the two furnaces. 3.4 On line heat-treatment The heat-treatment that uses the residual heat of rolling to accelerate the cooling, and obtains fine-grained pearlite structure.4 Ordering Required InformationThe user shall provide the following basic information when ordering products. a) Product name; b) Product standard number; c) Rail type; d) Steel designation and delivery status; c) 75m rail. 71m, 72m, 73m, 74m; d) 100m rail. 95m, 96m, 97m and 99m. 5.5.4 The length of curved and shortened rail for the rail with specified length of 75m and 100m, as well as the length of rail with other specified length and of the shorter rail shall be negotiated by the supplier and the purchaser, and indicated in the contract. 5.5.5 The matching quantity of the shorter rail shall be negotiated by the supplier and the purchaser, and indicated in the contract; but shall not exceed 10% total ordering weight of one batch; the rail with bolt hole shall not have shorter rail. 5.5.6 The rail shall be delivered by theoretical mass. Steel density is 7.85 g/cm3.The theoretical mass of the rail can refer to Appendix A.6 Technical Requirements6.1 Manufacturing method 6.1.1 Rail steel shall be smelted in an alkaline oxygen converter or electric arc furnace; and subjected to refining and vacuum degassing outside the furnace. 6.1.2 Rail shall be manufactured by the continuous casting billets. 6.1.3 Rail shall be multi-stage high pressure jet descaling during the rolling process to effectively remove the scale. 6.1.4 The rolling compression ratio of the rail shall be no less than 9.1. 6.1.5 The rail shall be straightened by the two-stage roller straightening machine for the horizontal axis X-Y and the perpendicular axis X-Y direction on the section. Only once roll-straightening is allowed. If there is end or local unevenness, the four-side press machine can be used for supplemented straightening. The drilled rail shall be firstly conducted supplemented straightening, then drill holes. 6.1.6 The welding rail shall not be subjected to rail end heat-treatment; while the U71Mn hot-rolled drilled rail shall be subjected to the rail end heat-treatment; when it requires no heat-treatment, it shall be indicated in the contract; the hot-rolled drilled rail with other steel designations shall not be subjected to the rail end heat-treatment. 6.2 Designation and chemical composition 6.2.1 The steel designation, chemical composition and residual elements (smelting analysis) shall conform to the provisions of Tables 3 and 4.If the supplier guarantees, the residual element test can be neglected. 6.8 Macrostructure The macrostructure of the cross-section acid-etched test piece of the rail shall conform to the provisions of Appendix C. 6.9 Drop-Weight The rail shall be subjected to the drop-weight test; the specimen shall not appear breaks after once hammering. The deflection value shall be given in the quality certificate for reference. 6.10 Surface quality 6.10.1 The rail surface shall be free of cracks. Rail shall not fall from the height of 1m above. 6.10.2 The running surface of the rail (i.e. rail crown), lower surface of the rail base, and the protruding parts (except the hot-rolled marking) that affect the installation of the joint bar within 1m from the rail end shall be ground. 6.10.3 The maximum allowable depth of the rail wear, thermal scratches, longitudinal lines, folds, scale indentation, rolling marks, etc. formed in the hot state shall be as follows. a) Rail running surface 0.5mm; b) Other parts of the rail 0.6mm. The number of scratches on the rail running surface, lower surface of the rail base and longitudinal fore-plate in the rail length direction is allowed to be 2 at the maximum; their depth shall not exceed the relevant specified value. The repeated fore-plate scratches along the same axis can be regarded as one. The maximum width of the fore-plate scratch is allowed to be 4mm; the ratio between the width and depth shall be greater than or equal to 3.1. The periodic hot-rolled marks produced by the rolls can be approved as one place and can be ground. 6.10.4 The maximum allowable depth of the defects such as longitudinal and lateral scratches of rail formed in the cold state shall be as follows. a) Rail running surface and lower surface of rail base 0.4mm (no lateral scratches on the lower surface of the rail base); b) Other parts of the rail 0.5mm. 6.10.5 The rail surface shall be free of the damage from martensite or white phase structure, and shall be eliminated if any. 6.10.6 Surface defect detection and grinding. The surface defect depth shall be detected by a depth detector. When the depth can’t be measured, it shall be confirmed by test. When grinding the surface defects, the contour of the grinding surface shall be smooth; ensure the microstructure of the rail after grinding shall not be affected. Maximum allowable grinding depth. a) Rail running surface 0.5mm; b) Other parts of the rail 0.6mm. The geometrical deviation of the rail after grinding shall conform to the provisions of Table 1. In the range of 1m from the welding rail to the rail end, the rail running surface and rail head side, except for the protruding part, shall not be ground. If the rail section size and straightness are unqualified, except for the protruding part, shall not be treated by grinding. When the hot and cold damage of the rail meets the requirements of 6.10.3 and/or 6.10.4, and is harmless to the use of rail, the grinding can be neglected. 6.10.7 The burrs on the rail end face and the edge surface of the bolt hole shall be removed. 6.10.8 The surface of the rail base shall be automatically detected along the entire length of the rail. The used equipment shall be capable of detecting the artificial defect with the size specified in Table 9.The size tolerance of the artificial defect shall be ±0.1mm. When detecting by the rail base automatic detection technology, the detecting range shall be at least 60mm wider than the center of the rail base. Use the test rail with artificial defect to calibrate once every 8h. When the automatic detection equipment can’t work properly, the manual inspection shall be conducted. Table 9 – Size of Artificial Defect Unit. mm 6.11 Ultrasonic flaw detection The entire length of the rail shall be continuously tested for ultrasonic flaw detection; the defects shall not exceed φ2.0mm artificial defect equivalent. Defect depth Defect length Defect width8 Inspection Rules8.1 Supervision The purchaser reserves the right to supervise the various processes and inspections of the rail production; and check these inspection results. 8.2 Type inspection 8.2.1 The supplier shall perform the type inspection under the following conditions. a) Before the new products are laid on the road; b) Major changes in the production processes and production equipment, etc.; c) Every 5 years for normal production; d) Production suspension for more than 6 months. 8.2.2 All inspections shall be carried out in the qualified laboratory. 8.2.3 The supplier shall provide all inspection records, calibration and calculation values for which the final inspection results are based on to the purchaser. 8.2.4 Type inspection shall include all items in the Table 12.The specimens with serial numbers of 12~20 shall be cut from the straightened rails; and these specimens shall not be subjected to the mechanical and heat treatment anymore. The specimens for fracture toughness, fatigue crack growth rate and fatigue test shall be cut from 3 sample rails, which shall be taken from different heats and different sequence numbers. The residual stress test shall select 6 sample rails. The sampling positions and test methods for each inspection can refer to Table 12. 8.3 Exit-factory inspection 8.3.1 Batching rules. Each batch consists of the rails rolled by the steel billets continuous casted by the several furnaces of molten steel with the same designation and the same rail type. 8.3.2 The exit-factory inspection of the rails shall be carried out by the quality inspection department of the supplier. If necessary, the purchaser reserves the right to conduct random inspection; the specific items shall be agreed upon by the supplier and the purchaser at the time of ordering. 8.3.3 The exit-factory inspection includes all items from SN 1~16; its inspection frequency, sampling position and test method can refer to Table 12. of the first and second sampling points of the same casting flow. At least one of the two reinspection specimens is taken from the same billet as the initial inspection sample; the rail between the two reinspection specimens shall not be accepted. If the reinspection results of the two reinspection specimens meet the requirements, then the rest rails of such batch can be accepted. If one reinspection specimen is unqualified, samples can be taken continuously till it is qualified. 8.4.4.3 When the macrostructure is difficult to identify, further inspection can be performed at a higher magnification. 8.4.5 Drop-weight When the drop-weight test result does not conform to the provisions of this Standard, one sample shall be taken for inspection of all other heats of the same sequence. For the furnace where the initial inspection is unqualified, one sample shall be taken for re- inspection on both sides of the first and second sampling points of the same casting flow. At least one of the two reinspection specimens is taken from the same billet as the initial inspection specimen; the rail between the two reinspection specimens shall not be accepted. If the results of the two inspection specimens meet the requirements, the rest rail of such furnace can also be accepted. If there is still an unqualified reinspection specimen, the sample can be taken continuously for reinspection till it is qualified. 8.4.6 Decarbonization layer When the initial inspection result is unqualified, reinspection shall be taken on the two adjacent rails of the same batch. If the reinspection results of the two reinspection specimens are qualified, then the rest rails of such batch can be accepted. If the reinspection specimen is unqualified, then continue to take samples on the two adjacent rails for reinspection till it is qualified. The rail between the two reinspection specimens shall not be accepted. 8.4.7 Microstructure When the initial inspection result is unqualified, reinspection shall be taken on the two adjacent rails of the same batch. If the reinspection results of the two reinspection specimens are qualified, then the rest rails of such batch can be accepted. If the reinspection specimen is unqualified, then continue to take samples on the two adjacent rails for reinspection till it is qualified. The rail between the two reinspection specimens shall not be accepted. 8.5 Numerical rounding off Except as otherwise stipulated in the contract or the order, when it is necessary to assess whether the test result meets the specified value, The given test results shall be rounded off to the digit marked by the standard number of the specified value; its type, steel designation, characteristic symbol of heat-treated rail H, manufacturing year and month, etc. 9.2 Quality certificate The delivered rails shall be attached with the quality certificate issued by the quality inspection department of the manufacturer, the contents of which shall include. a) Manufacturer name; b) Purchaser name; c) Rail type (including drilled rail or welding rail); d) Contract No.; e) Standard number; f) Steel designation, delivery sate, or code of heat-treated rail; g) Quantity and length (specified length and short length); h) Heat; i) Item 1~16 inspection results specified in Table 12 of this Standard; j) Exit-factory date.10 Quality Assurance10.1 Quality assurance system 10.1.1 The supplier shall have a quality management system certified by an independent agency and conform to the provisions of GB/T 19001. 10.1.2 The purchaser may further audit the quality assurance system if it is deemed necessary. 10.2 Quality assurance period 10.2.1 From the effective date of the manufacturing year N to December 31 of the year N+5, the supplier shall ensure that the rail does not exceed any harmful defects in the manufacturing field specified in this Standard. 10.2.2 If the rail can’t be used due to the brakeage or other defects during the quality assurance period, the personnel of both the supplier and the purchaser shall conduct physical inspection and further laboratory inspection if necessary. If the defect is The microstructure of hardened layer shall be fine-grained pearlite, allowing for a small amount of ferrite, not allowing for martensite, bainite, and the like. E.4 Appearance Rail shall be free of quenching cracks, over-burning, etc. E.5 Test E.5.1 Tread hardness test At a distance about 50mm from the rail end, the decarbonization layer on the top surface of the rail shall be ground; then perform the Brinell hardness and Rockwell Hardness tests. Each quenching machine checks at least two rails per shift. Perform as per the methods specified in GB/T 231.1 and GB/T 230. E.5.2 Shape test of hardened layer E.5.2.1 Test rail Take a 500mm-long rail from the rails with the same type, the same steel designation and the same heat-treatment batch; the rail shall take the heat-treatment on then end as the test rail. E.5.2.2 Specimen The specimen shall be prepared as per the following provisions. a) Cross-section specimen. cut the cross-section specimen at a position about 20mm from the rail end on the test rail; and grind the saw surface. b) Longitudinal section specimen. the remaining test rail head after cutting the cross-section specimen is longitudinally cut along the center line; take any block of it, then grinding its longitudinal section. E.5.2.3 Test method Use 5% nitric acid solution to etch the ground sample, and show the shape of the hardened layer. E.5.3 Hardness and distribution test of the hardened layer E.5.3.1 Test rail and specimen It shall be performed as per the provisions of F.5.2.1 and F.5.2.2. E.5.3.2 Test methodAppendix F(Normative) Method for Measuring Longitudinal Residual Stress of Rail Base Surface F.1 Introduction The assessing method for residual stress. firstly, attach the resistance strain gauge to the rail base surface; then gradually cut off and isolate the part attached with strain gauge from the rail; use the released strain value to assess the original residual stress. F.2 Strain gauge and its past position The used strain gauge shall be closed type with length of 3mm; its sensitivity factory shall be better than ±1%. In order to measure the longitudinal strain at the position shown in Figure F.1, the strain gauge shall be attached to the rail base surface. The treatment of rail base surface where the strain gauge is attached and the use method of the strain gauge shall conform to the suggestion of the strain gauge manufacturer (any surface treatment shall not cause change for the residual stress on the rail base). The strain gauge shall be attached to the center of 1m-long rail. In the center of patch area of the sample rail, cut a 20mm-thick sample (see Figure F.2); measure the strain value released before and after cutting (properly cooling is required during the cutting). The residual stress value is calculated by multiplying the strain difference before and after cutting by 2.07×105MPa. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
