Test method for exploring optimal low-temperature tempering temperature of steel rail
By analyzing the mechanical properties and microstructure of the rails at different tempering temperatures, the optimal low-temperature tempering temperature was determined, solving the problem of optimizing the mechanical properties of the rails, improving the hardness and toughness of the rails, and reducing the risk of crack propagation.
Patent Information
- Application Number
- CN202511059488.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies make it difficult to determine the optimal low-temperature tempering temperature for rails, which affects the optimization of their mechanical properties and crack resistance.
By analyzing the changes in mechanical properties and microstructure of rails under different tempering temperatures, tensile performance testing, impact performance testing, tread hardness testing, and microstructure analysis were conducted to determine the optimal low-temperature tempering temperature.
The optimal low-temperature tempering temperature for the rails was determined, which improved the overall mechanical properties of the rails, enhanced their hardness and toughness, and reduced the risk of crack propagation.
Smart Images
Figure CN120907962A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of steel rail heat treatment, and particularly relates to a test method for exploring optimal low-temperature tempering temperature of a steel rail. BACKGROUND
[0002] Nowadays, the railway construction and transportation industry develops rapidly, the service safety of steel rails is highly valued, and the demand for developing steel rails with excellent performance is increasingly urgent. Tempering is part of the heat treatment process, and the mechanical properties of materials are improved through tempering. The low-temperature tempering temperature range is 150-350 DEG C, and the main function is to improve the mechanical properties of steel, including improving the hardness, toughness and crack resistance of the steel rail. The low-temperature tempering is to heat the steel rail to a lower temperature, so that the internal stress of the steel rail is released, the risk of crack propagation of the steel rail is reduced, and the fatigue resistance of the steel rail in long-term use is improved. By changing the tempering temperature, the mechanical properties and microstructure change trend of the steel rail are analyzed, the influence of the tempering temperature on the microstructure and performance of the steel rail is explored, the optimal low-temperature tempering temperature of the steel rail is determined, and reference is provided for the performance optimization of the steel rail. SUMMARY
[0003] The purpose of the application is to provide a test method for exploring the optimal low-temperature tempering temperature of a steel rail, to analyze the mechanical properties and microstructure change trend of the steel rail by changing the tempering temperature, to explore the influence of the tempering temperature on the microstructure and performance of the steel rail, and to determine the optimal low-temperature tempering temperature of the steel rail, thereby providing reference for the performance optimization of the steel rail.
[0004] To solve the above technical problems, the application adopts the following technical scheme:
[0005] The test method for exploring the optimal low-temperature tempering temperature of the steel rail comprises the performance test of the online heat treatment state of the steel rail, i.e. the tensile strength of the rail head, the elongation after fracture and the hardness of the top surface center line; at least two kinds of pearlitic steel rails are selected for testing;
[0006] The test method comprises tempering the online heat treatment state steel rail; one meter of the online heat treatment pearlitic steel rail is tempered;
[0007] The test method comprises comparative analysis of the microstructure and performance of the steel rail under different tempering processes, and adopts tensile property detection, impact property detection, tread hardness detection and microstructure analysis; the mechanical property parameters before and after tempering and under different tempering temperatures are compared;
[0008] The test method comprises comprehensive comparative analysis of the mechanical property parameters of the steel rail before and after tempering, and determination of the optimal low-temperature tempering temperature of the steel rail.
[0009] Further, the variable control in the tempering process comprises tempering temperature, heating time, holding time and cooling mode.
[0010] Further, the test will be at least 2 kinds of pearlitic rail at 200 DEG C, 280 DEG C, 350 DEG C low temperature tempering, using air cooling cooling mode, heating time 10-20 min, 4-8 hours.
[0011] Further, the temperature is kept for 6 hours.
[0012] Further, the main role of low temperature tempering is to improve the mechanical properties of the steel, including improving the hardness, toughness and crack resistance of the rail.
[0013] Further, the test selects two kinds of pearlitic rail for testing.
[0014] Further, the method changes the tempering temperature, analyzes the mechanical properties and microstructure change trend of the rail, explores the influence of the tempering temperature on the microstructure and performance of the rail, determines the optimal low temperature tempering temperature of the rail, and provides a reference for the performance optimization of the rail.
[0015] Compared with the prior art, the beneficial technical effects of the present application are:
[0016] The present application changes the tempering temperature, analyzes the mechanical properties and microstructure change trend of the rail, explores the influence of the tempering temperature on the microstructure and performance of the rail, determines the optimal low temperature tempering temperature of the rail, and provides a reference for the performance optimization of the rail DETAILED DESCRIPTION
[0017] The present application will be further described below in conjunction with the drawings.
[0018] Figure 1 For the tensile properties of the rail head of the rail before and after tempering, (a) comparison of tensile strength before and after tempering, (b) comparison of elongation before and after tempering;
[0019] Figure 2 For the hardness comparison of the top surface center line of the rail head before and after tempering of the rail;
[0020] Figure 3 For the pearlitic microstructure of the tempered rail, (a) rail A, 200 DEG C, (b) rail A, 280 DEG C, (c) rail A, 350 DEG C, (d) rail B, 200 DEG C, (e) rail B, 280 DEG C, (f) rail B, 350 DEG C. DETAILED DESCRIPTION
[0021] A test method for exploring the optimal low temperature tempering temperature of the rail, comprising: the present application explores the optimal low temperature tempering temperature of the rail according to the mechanical properties and microstructure change of the rail under different tempering temperatures, and to a certain extent, provides a systematic test idea in the performance optimization of the rail.
[0022] EMBODIMENT
[0023] The test method includes the on-line heat treatment state performance test of the steel rail, i.e. the rail head tensile strength, the elongation after fracture and the top surface center line hardness. The test selects A and B pearlite steel rails for testing.
[0024] The test method includes the tempering treatment of the on-line heat treatment state steel rail. The test performs the tempering treatment on one meter of the on-line heat treatment A and B pearlite steel rails.
[0025] The variable control in the tempering treatment includes the tempering temperature, the heating time, the holding time, the cooling mode, etc. The test performs the low temperature tempering of the A and B pearlite steel rails at 200℃, 280℃ and 350℃, adopts the air cooling cooling mode, the heating time is 10-20min and the holding time is 6 hours.
[0026] The test method includes the structure and performance comparative analysis of the steel rail under different tempering processes, adopts the tensile performance detection, the impact performance detection, the tread hardness detection, the microstructure analysis, etc. The test compares the mechanical performance parameters before and after the tempering and under different tempering temperatures, see Figure 1 、 2 、3.
[0027] The test method includes the comprehensive comparative analysis of the mechanical performance parameters of the steel rail before and after the tempering, and determines the best low temperature tempering temperature of the steel rail. The low temperature tempering in the 200-350℃ interval can improve the comprehensive mechanical performance of the steel rail. The tensile performance and the tread hardness of the A and B steel rails after the tempering are superior to the on-line heat treatment state, and improve with the increase of the tempering temperature. In the 200-350℃ temperature range, the tensile strength of the A and B steel rails after the 350℃ tempering treatment increases by 2% and 4% respectively, the elongation increases by 2-3% and 1-2% respectively, and the tread hardness (HBW) increases by 13 and 8 respectively. In summary, the best low temperature tempering temperature of the A and B pearlite steel rails is 350℃.
[0028] The above described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by the ordinary skilled in the art shall fall into the protection scope determined by the claims of the present application.
Claims
1. A test method for investigating optimum low temperature tempering temperature of a steel rail, characterized by, The test method comprises on-line heat treatment state performance test of the steel rail, i.e. rail head tensile strength, elongation after fracture and top surface center line hardness; at least two kinds of pearlitic steel rails are selected for test; The test method comprises tempering treatment of the on-line heat treatment state steel rail; one meter of the on-line heat treatment pearlitic steel rail is subjected to tempering treatment; The test method comprises comparative analysis of the structure and performance of the steel rail under different tempering processes, and adopts tensile property detection, impact property detection, tread hardness detection and microstructure analysis; the mechanical property parameters of the steel rail before and after tempering and under different tempering temperatures are compared; The test method comprises comprehensive comparative analysis of the mechanical property parameters of the steel rail before and after tempering, and determination of the optimal low-temperature tempering temperature of the steel rail.
2. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 1, characterized by, The variable control in the tempering treatment comprises tempering temperature, heating time, holding time and cooling mode.
3. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 1, characterized in that, The test is conducted on at least two kinds of pearlitic steel rails under low-temperature tempering at 200 DEG C, 280 DEG C and 350 DEG C, and the cooling mode is air cooling, the heating time is 10-20 min and the holding time is 4-8 hours.
4. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 3, characterized in that, The holding time is 6 hours.
5. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 1, characterized in that, The main function of the low-temperature tempering is to improve the mechanical property of the steel, including improvement of the hardness, toughness and crack resistance of the steel rail.
6. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 1, characterized in that, Two kinds of pearlitic steel rails are selected for test.
7. The test method for investigating optimum low temperature tempering temperature of steel rail according to claim 1, characterized in that, The method changes the tempering temperature, analyzes the mechanical property and microstructure change trend of the steel rail, explores the influence of the tempering temperature on the structure and performance of the steel rail, determines the optimal low-temperature tempering temperature of the steel rail, and provides reference for performance optimization of the steel rail.