Steel rail residual stress testing device

Abstract

The utility model provides a steel rail residual stress testing device, which comprises a strain gauge adhered to the central position of the bottom surface of a steel rail; the hard insulating plastic plate is arranged on one side of the strain gauge; the first binding post and the second binding post are arranged on the hard insulating plastic plate in a staggered mode and are parallel to the wide side of the steel rail. And the resistance strain gauge is electrically connected with the strain gauge through the first binding post and the second binding post by a lead and is used for measuring the residual stress of the steel rail. According to the utility model, the two binding posts are arranged on the hard insulating plastic plate in a staggered manner, so that the wire and the binding posts can avoid a saw blade when sawing a steel rail sample block, thereby meeting the measurement requirement.

Description

Technical Field

[0001] The utility model relates to the technical field of rail residual stress testing, in particular to a rail residual stress testing device. Background Art

[0002] With the development of the railway transportation industry, high-speed and heavy-duty railways have higher requirements for the stability and safety of rail service. When in service, the rails are subjected to alternating loads perpendicular to the rail head and periodically changing friction between the wheel and rail. If the above two forces are superimposed on the residual stress in the rail, it is very easy to induce cracks inside the rail and cause the cracks to expand rapidly during service, resulting in rail breakage and unnecessary safety accidents. The alternating loads and longitudinal friction that the rails are subjected to during service are external factors and cannot be changed. Therefore, controlling the residual stress of the rails within a reasonable range is an important indicator for rail production. It is also a must-check item before the rails leave the factory. At present, the main basis for residual stress detection is the implementation of standard TB / T2344-2020. The standard requires that the strain gauge be pasted to the center of the bottom surface of a 1m long rail and a 20mm thick sample be sawed (see Figure 1 ), measure the strain value released before and after sawing, and then multiply it by 2.07×105MPa to get the residual stress of the rail.

[0003] In fact, when sawing rails, it is difficult to ensure that the thickness of the sample is 20mm due to the constraints of strain gauges, terminals and wires. When the terminals and strain gauges are fixed, in order to ensure good contact between the two, the wires cannot move significantly. However, when sawing, the saw blade is perpendicular to the wire. In order to avoid the wire being cut during sawing, the cutting line needs to be appropriately away from the terminal, and the wire is gently pulled up vertically to avoid the saw blade to complete the cutting. (See Figure 2 ) This will result in the slice thickness exceeding 20mm, sometimes even reaching 30mm, which does not meet the standard requirements. According to theoretical analysis, this will lead to smaller measurement results and affect the measurement accuracy. Utility Model Content

[0004] In order to solve the above problems, the utility model aims to provide a rail residual stress testing device.

[0005] To achieve the above purpose, the utility model provides the following solutions:

[0006] A rail residual stress testing device, comprising:

[0007] The strain gauge is pasted on the center of the bottom surface of the rail;

[0008] A hard insulating plastic plate, arranged on one side of the strain gauge;

[0009] The first terminal and the second terminal are staggeredly arranged on the hard insulating plastic plate, and the first terminal and the second terminal are parallel to a side of the width of the rail;

[0010] The resistance strain gauge is electrically connected to the strain gauge through a wire passing through the first terminal and the second terminal, and is used to measure the residual stress of the rail.

[0011] Preferably, the side length of the hard insulating plastic plate is 10 mm and the thickness is 0.2 mm.

[0012] Preferably, the first terminal and the second terminal are offset in the vertical direction, and the vertical overlap portion is less than 0.5 mm.

[0013] Preferably, the horizontal spacing between the first binding post and the second binding post is 2 mm-5 mm.

[0014] Preferably, the first terminal and the second terminal are copper sheets with a length of 6 mm, a width of 2 mm and a thickness of 0.2 mm.

[0015] According to the specific embodiments provided by the utility model, the utility model discloses the following technical effects:

[0016] The utility model provides a rail residual stress testing device. Compared with the prior art, the utility model sets two terminal posts in a staggered manner on a hard insulating plastic plate, so that the wires and the terminal posts can avoid the saw blade when sawing a rail sample block, thereby meeting the measurement requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram of the bottom of a steel rail provided by the utility model;

[0019] Figure 2 A schematic diagram of a conventional connection method for a terminal provided by the utility model;

[0020] Figure 3 A schematic diagram of the connection method of the staggered terminal provided by the utility model;

[0021] Figure 4 A schematic diagram of a conventional terminal provided by the utility model;

[0022] Figure 5This is a schematic diagram of the staggered terminal provided by the utility model. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0026] See also Figure 3-5 , a rail residual stress testing device, comprising:

[0027] The strain gauge is pasted on the center of the bottom surface of the rail;

[0028] A hard insulating plastic plate, arranged on one side of the strain gauge;

[0029] The first terminal and the second terminal are staggeredly arranged on the hard insulating plastic plate, and the first terminal and the second terminal are parallel to a side of the width of the rail;

[0030] The resistance strain gauge is electrically connected to the strain gauge through a wire passing through the first terminal and the second terminal, and is used to measure the residual stress of the rail.

[0031] Furthermore, the side length of the rigid insulating plastic plate is 10 mm and the thickness is 0.2 mm. The first terminal and the second terminal are misaligned in the vertical direction, and the vertical overlap portion is less than 0.5 mm. The horizontal spacing between the first terminal and the second terminal is 2 mm-5 mm. The first terminal and the second terminal are made of copper sheets with a length of 6 mm, a width of 2 mm, and a thickness of 0.2 mm.

[0032] The rail residual stress testing device of the utility model is further described below in conjunction with specific embodiments:

[0033] In order to ensure that the thickness of the rail sample meets the standard requirement of 20mm when sawing, and the wire is not easily cut during the sawing process, the utility model provides a staggered terminal, which can ensure that the thickness of the sawn sample meets the standard requirements. Finally, according to the connection method of the staggered terminal, the thickness of the sample can be ensured to be 20mm, meeting the requirements of TB / T2344. The implementation process is as follows:

[0034] (1) Select a hard insulating plastic plate with a side length of 10 mm and a thickness of 0.2 mm;

[0035] (2) According to Figure 5 Inlay copper sheets with a length of 6mm, a width of 2mm and a thickness of 0.2mm. Note that the two copper sheets remain parallel and have obvious vertical misalignment, the vertical overlap is less than 0.5mm, and the horizontal spacing is 2mm≤≤5mm.

[0036] (3) According to Figure 3 The strain gauge, wire, terminal and resistance strain gauge are connected in a way.

[0037] (4) Measure the initial value of strain in the resistance strain gauge.

[0038] (5) The sample was cut with a band saw and the thickness of the sample was measured to be 20 mm, which met the standard requirements.

[0039] (6) After cutting, wait for the data to stabilize and measure the final strain value.

[0040] (7) The resistance strain gauge automatically reads the strain change value Δμε twice, and the residual stress = Δμε×2.07×105MPa.

[0041] According to the specific embodiments provided by the utility model, the utility model discloses the following technical effects:

[0042] The utility model provides a rail residual stress testing device. Compared with the prior art, the utility model sets two terminal posts in a staggered manner on a hard insulating plastic plate, so that the wires and the terminal posts can avoid the saw blade when sawing a rail sample block, thereby meeting the measurement requirements.

[0043] This article uses specific examples to illustrate the principles and implementation methods of the utility model. The above examples are only used to help understand the method and core ideas of the utility model. At the same time, for those skilled in the art, according to the ideas of the utility model, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the utility model.

Claims

1. A rail residual stress testing device, characterized in that: include: The strain gauge is pasted on the center of the bottom surface of the rail; A hard insulating plastic plate, arranged on one side of the strain gauge; The first terminal and the second terminal are staggeredly arranged on the hard insulating plastic plate, and the first terminal and the second terminal are parallel to a side of the width of the rail; The resistance strain gauge is electrically connected to the strain gauge through a wire passing through the first terminal and the second terminal, and is used to measure the residual stress of the rail.

2. A rail residual stress testing device as claimed in claim 1, characterized in that: The side length of the hard insulating plastic plate is 10 mm and the thickness is 0.2 mm.

3. A rail residual stress testing device as claimed in claim 2, characterized in that: The first terminal and the second terminal are misaligned in the vertical direction, and the vertical overlap portion is less than 0.5 mm.

4. A rail residual stress testing device as claimed in claim 3, characterized in that: The horizontal distance between the first terminal and the second terminal is 2 mm-5 mm.

5. A rail residual stress testing device as claimed in claim 4, characterized in that: The first terminal and the second terminal are made of copper sheets with a length of 6 mm, a width of 2 mm and a thickness of 0.2 mm.

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