A method for grinding uneven rail surface within 3m of a high-speed railway rail welding joint

Abstract

The present invention discloses a method for grinding the uneven rail surface within 3m of a high-speed railway rail welding joint, which belongs to the field of railway line engineering. First, it is necessary to determine the abnormal vibration section where the wheel-rail impact force of the high-speed railway is too large or the wheel-rail noise is abnormal, and collect the data of the uneven rail surface within 3m of the high-speed railway rail welding joint in the abnormal vibration section; at the same time, it is also necessary to collect the rail profile data within 3m of the rail welding joint and record the rail surface state. Subsequently, the collected data of uneven rail surface are statistically analyzed, and a corresponding small machine grinding scheme is designed for the over-limit rail welding joint; according to the designed grinding scheme, small grinding mechanical equipment is used to grind the uneven rail surface of the rail welding joint, and the consistency of the rail profile within the grinding range must be ensured. Finally, the uneven rail surface and rail profile within 3m of the rail welding joint are quality inspected. Through the method proposed by the present invention, the common problems such as uneven low pedaling caused by over-grinding and abnormal light band after driving caused by poor rail profile are eliminated.

Description

Technical Field

[0001] The invention belongs to the field of railway line engineering and is a method for grinding uneven rail surfaces within a 3m range of a high-speed railway rail welding joint. Background Art

[0002] The local unevenness of the rails will cause a sharp increase in the wheel-rail impact force and a surge in the wheel-rail contact stress. Many types of rail damage are related to the wheel-rail contact stress. Not only will the substructure under the rails be subjected to a large impact, causing structural damage, but the impact load will also be fed back to the various components of the vehicle, causing fatigue cracks, and in severe cases, fatigue fractures of vehicle components. The unevenness of the track surface of high-speed railways is mainly concentrated in the rail welding joints, especially some joints welded on site. The quality of such welding joints is poor. After multiple high-frequency impacts, the uneven straightness of the welding joints is easy to exceed the limit, affecting the safety of high-speed train operation, passenger comfort and other performance.

[0003] In recent years, domestic and foreign scholars have conducted a series of studies on rail welded joints. Ding Wei et al. studied the measurement method of the straightness of rail welded joints. The results showed that the rail welding and grinding process can be improved according to different straightness curves to improve the quality of welded joints. Cai Zhipeng, Zhai Wanming, Gao Jianmin et al. analyzed the influence of the parameters related to the unevenness of rail welds on the wheel force response under high-speed railway conditions based on the vehicle-track coupling dynamics theory, and proposed a series of safety limits for the unevenness and straightness of high-speed railway rail welded joints.

[0004] At present, scholars at home and abroad mainly conduct research on the unevenness of rail welding joints within 1m, and the relevant maintenance rules also only stipulate and require the unevenness of the rail surface within 1m. According to relevant project research, due to poor on-site welding process quality and non-standard grinding, the rail surface smoothness within 3m of the rail welding joint is prone to problems such as poor smoothness. For example, the Beijing-Baotou Passenger Dedicated Line and the Nanning-Guangzhou Railway both have poor smoothness of rail welding joints within 3m, resulting in excessive dynamic inspection and serious abnormal noise in wheel-rail contact.

[0005] For the problem of excessive straightness of rail welded joints, a small grinder is usually used to grind the rails to keep the joints smooth. At present, the grinding construction units have different methods for dealing with uneven rail welded joints, especially for the unevenness within 3m of the rail welded joints. At the same time, the relevant maintenance rules do not require the grinding equipment, grinding process, and testing equipment for grinding uneven rail surfaces within 3m of the rail welded joints. Summary of the invention

[0006] In view of the above problems, the present invention proposes a method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint, and puts forward requirements for the detection, grinding method and acceptance standard of the uneven rail surface within 3m of the rail welding joint, so as to ensure that the grinding will eliminate the common problems such as uneven low-stepping caused by over-grinding and abnormal light band after driving caused by poor rail profile.

[0007] The present invention provides a method for grinding the uneven rail surface within 3m of a high-speed railway rail welding joint, which is achieved by the following steps:

[0008] Step 1: Determine the abnormal vibration section of the high-speed railway;

[0009] Step 2: Collect data on rail surface irregularity within 3m of the high-speed railway rail welding joint in the abnormal vibration section;

[0010] Step 3: Collect the rail profile data within 3m of the rail welding joint and record the rail surface status;

[0011] Step 4: Analyze the collected rail surface unevenness data one by one, and design corresponding grinding schemes for over-limit rail weld joints, including grinding high points, grinding amount, grinding direction and grinding range;

[0012] Step 5: Use small grinding machinery to grind the uneven rail surface of the rail welding joint to improve the unevenness of the rail surface and ensure the consistency of the rail profile within the grinding range;

[0013] Step 6: Conduct quality inspection on the unevenness of the rail surface and the rail profile within 3m of the rail welding joint.

[0014] The advantages of the present invention are:

[0015] 1. The method for grinding uneven rail surfaces within 3m of high-speed railway rail welded joints of the present invention is innovative compared with the traditional rail welded joint grinding process. It provides a method for grinding rail welded joints within 3m using an intelligent CNC profiling fine grinder, and then requires and improves the grinding process of traditional equipment, traditional vertical grinders and profiling grinders.

[0016] 3. The method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint of the present invention puts forward requirements for the quality inspection standards of the uneven rail surface and rail profile after grinding, and prevents the common problems such as uneven low treading caused by over-grinding and abnormal light band after driving caused by poor rail profile.

[0017] 4. The method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint of the present invention provides a new solution to the wheel-rail impact problem of the high-speed railway rail welding joint, changing the traditional concept of only focusing on the uneven rail surface within 1m of the rail welding joint.

[0018] 5. The method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint of the present invention can effectively improve the dynamic contact relationship between the wheel and the rail and reduce the wheel-rail noise through on-site implementation of multiple lines, so as to achieve the purpose of improving the riding comfort of passengers.

[0019] 6. The method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint of the present invention can accurately determine the grinding range and grinding amount of the uneven rail surface, and can minimize the consumption of the parent material by grinding. The grinding efficiency is improved, the service life of the rail parent material is increased, and the amount of grinding consumables is reduced. The method has good economic benefits.

[0020] 7. The method for grinding the uneven rail surface within 3m of the high-speed railway rail welding joint of the present invention is also applicable to the treatment of local rail surface unevenness at any position of the high-speed railway, and can be applied to the rectification of rail surface unevenness and the periodic preventive grinding of rail welding joints, which has great promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of the method for grinding the uneven rail surface within 3m of a high-speed railway rail welding joint according to the present invention;

[0022] Figure 2 Obtain a schematic diagram of rail surface unevenness within 3m of the rail welding joint for splicing;

[0023] Figure 3 The rail surface within 3m of the rail welding joint is not smooth;

[0024] Figure 4 It is the unevenness and straightness of the rail surface within 3m of the rail welding joint;

[0025] Figure 5 Schematic diagram of "low" roughness grinding. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0027] The present invention provides a method for grinding the uneven rail surface within 3m of a high-speed railway rail welding joint, such as Figure 1 As shown, the specific steps are as follows:

[0028] Step 1: According to the dynamic inspection data and the number of passengers added, determine the abnormal vibration section where the high-speed railway wheel-rail impact force is too large or the wheel-rail noise is abnormal; or the engineering department shall specify the location and range of the rail welding joints that need to be rectified.

[0029] The above step 1 is mainly carried out by the engineering department, which is the content of the daily inspection of the engineering department of the railway bureau. According to the daily inspection of the engineering department, the abnormal vibration section caused by the uneven track surface of the rail welding joint is determined.

[0030] Step 2: Collect the data of rail surface irregularity within 3m of the rail welding joint (1.5m on both sides of the weld) in the abnormal vibration section. The data of rail surface irregularity within 3m of the rail welding joint can be collected by traditional equipment 1m steel ruler + feeler gauge, 1m electronic straight ruler and rail straightness measuring instrument, the specific method is as follows:

[0031] 1. 1m steel ruler or 1m electronic straight ruler + feeler gauge measurement method

[0032] The data overlap method is required to obtain the track surface unevenness data within a range of 3m through the traditional 1m steel ruler + feeler gauge and 1m electronic flat ruler measuring equipment. Before measuring, use a tape measure to measure the position within 3m of the rail welding joint, and make a mark every 0.5m. Then use the above-mentioned measuring equipment to measure the track surface unevenness data of 5 sections of 1m rails from left to right. The starting points of the 5 sections of 1m rails are the left end of the 3m range and every 0.5m to the right, thereby obtaining 5 1m rail surface unevenness data. Among the 5 data, there is 0.5m of data between each 2 consecutively measured 1m rail surface unevenness data that were repeatedly measured, such as Figure 2 Therefore, the data splicing method is used to obtain the rail surface unevenness data within 3m of the rail welding joint through 5 consecutive 1m rail surface unevenness data.

[0033] 2. Rail straightness measuring instrument method

[0034] The rail straightness measuring instrument can be used to perform continuous measurements on the rail surface, and can directly obtain the rail surface unevenness data within 3m of the rail at one time.

[0035] The 3m track surface irregularity data obtained by splicing the above data or directly collecting is as follows: Figure 3 shown.

[0036] Step 3: With the rail welding joint as the center, use the rail profile measuring instrument to collect rail profile data for every half-sleeper interval within 3m of the rail welding joint, and take photos to record the rail surface status and light band width.

[0037] Step 4: Analyze the track surface irregularity data collected in step 2 one by one, and classify them into unqualified and qualified according to their straightness. The straightness results are as follows: Figure 4 As shown in the figure, whether the rail surface is smooth or not is determined according to the following limit standards:

[0038] 1. The straightness limit of any 1m rail surface unevenness within 3m of the rail welding joint is 0.2mm.

[0039] 2. The straightness limit of the 3m rail surface unevenness of the rail welding joint is -0.2mm~0.6mm.

[0040] If the collected rail surface unevenness data does not meet any of the above points, it will be judged as an unqualified rail welding joint. According to the unevenness data, the corresponding grinding plan is designed, including the grinding high point, grinding amount, grinding direction and grinding range.

[0041] Step 5: Polishing the Implementation

[0042] 1. Grinding with CNC profile grinding machine

[0043] The CNC square fine grinder uses a unique technology of fixed-point reciprocating profiling grinding, and only grinds the high point between the two fulcrums. The center of the CNC profiling fine grinder is placed on the "high point" where the rail surface is uneven. After starting, the grinder is controlled to perform repeated progressive grinding in the order of rail top surface - outer side - top surface - inner side - top surface - outer side, and the angle is adjusted by about 2° to 4° each time.

[0044] After all the "high points" have been polished, start from one end of the 3m range and polish at intervals of 0.5m to keep the rail surface within the 3m range at a good slope rate. The use of CNC profiling fine grinding machines will not affect the rail profile, so the rail profile does not need to be repaired after grinding.

[0045] 2. Grinding with traditional vertical grinder or profile grinder.

[0046] (1) Grinding of unevenness (convex unevenness)

[0047] Starting from the top surface of the rail, grind the local high point first, and operate the grinder on either side of the high point. The initial grinding wheel feed amount should not be too large. Feed it slowly, and advance it evenly and slowly towards the center of the uneven high point.

[0048] Then, the grinding is repeated in the order of rail top surface - outer side - top surface - inner side - top surface - outer side, and the angle is adjusted by about 2° to 4° each time. Finally, after the straightness of the rail top surface meets the standard, the side of the rail is ground and the rail profile is repaired at the same time.

[0049] (2) Grinding of "low" unevenness (concave unevenness)

[0050] Starting from the rail surface, first determine the length of the slope according to the low tread value obtained from the investigation and the slope rate of the work acceptance, and mark it. Then operate the lower knife handle (button) of the grinder at the center of the low tread. The grinding wheel feed should not be too large and feed slowly. According to the order of rail top surface - outer side - top surface - inner side - top surface - outer side, adjust the angle by about 2°~4° each time, and push the grinder back and forth evenly and steadily. After completing each angle conversion cycle, gradually extend the grinding range to both sides until the rail surface at 1.5m on both sides of the uneven center line is used as the reference point. The uneven straightness at this point is not less than 0, and the slope rate of the area beyond 1.5m meets the standard. Figure 5 After the uneven grinding is completed, repair the rail profile.

[0051] (3) Unsmooth grinding of the "saddle shape"

[0052] When grinding the uneven surface of a "saddle-shaped" rail, start from the rail surface. First, grind the relatively high points on both sides of the uneven center. Follow the order of rail top surface - outer side - top surface - inner side - top surface - outer side. Adjust the angle by about 2° to 4° each time, and push the grinder back and forth evenly and steadily. After the uneven grinding is completed, repair the rail profile.

[0053] After eliminating the high points on both sides, if the weld is still low, grind it according to the uneven low-step rail surface grinding process.

[0054] Step 6: Use a straightness measuring instrument to inspect the unevenness of the rail surface within 3m of the rail welding joint to meet the limit standard in step 4. At the same time, inspect the rail profile within the grinding range to ensure that the deviation between it and the rail profile in the ungrinded area is less than 0.5mm at the rail head of -15 to 25mm, and inspect one point for each half sleeper.

Claims

1. A method for grinding the uneven rail surface within 3m of a high-speed railway rail welding joint. Features: This is accomplished by following these steps: Step 1: Determine the abnormal vibration section of the high-speed railway; Step 2: Collect data on rail surface irregularity within 3m of the high-speed railway rail welding joint in the abnormal vibration section; Step 3: Collect the rail profile data within 3m of the rail welding joint and record the rail surface status; Step 4: Analyze the collected rail surface unevenness data one by one, and design corresponding grinding schemes for over-limit rail weld joints, including grinding high points, grinding amount, grinding direction and grinding range; Step 5: Use small grinding machinery to grind the uneven rail surface of the rail welding joint to improve the unevenness of the rail surface and ensure the consistency of the rail profile within the grinding range; the grinding method is vertical grinding machine and profile grinding machine grinding, including: (1) "High" uneven grinding; Starting from the top surface of the rail, grind the local high point first, and operate the grinder on either side of the high point. The initial grinding wheel feed amount is based on the grinding wheel just touching the rail surface, feed at a low speed, and advance at a low and uniform speed toward the center of the uneven high point; then grind in the order of rail top surface - outer side - top surface - inner side - top surface - outer side, and perform repeated progressive grinding, adjusting the angle by about 2° to 4° each time; (2) "Low" uneven grinding; Starting from the rail surface, first determine the length of the slope according to the low tread value obtained from the investigation and the slope rate of the operation acceptance, and make a mark; then operate the lower knife handle of the grinder at the center of the low tread, feed the grinding wheel at a low speed, and follow the order of rail top surface - outer side - top surface - inner side - top surface - outer side, adjust the angle by about 2°~4° each time, and push the grinder back and forth evenly and steadily; after completing each angle conversion cycle, gradually extend the grinding range to both sides, until the rail surface at 1.5m on both sides of the uneven center line is used as the reference point, the uneven straightness at this point is not less than 0, and the slope rate of the area outside 1.5m meets the standard. After the uneven grinding is completed, repair the rail profile; (3) "Saddle shape" is not smooth when polished; When grinding the "saddle-shaped" rail surface unevenness, start from the rail surface, first grind the relatively high points on both sides of the uneven center, follow the order of rail top surface - outer side - top surface - inner side - top surface - outer side, adjust the angle by about 2° to 4° each time, and push the grinder back and forth evenly and steadily; Step 6: Conduct quality inspection on the unevenness of the rail surface and the rail profile within 3m of the rail welding joint.

2. A method for grinding uneven rail surfaces within 3m of a high-speed railway rail weld joint as claimed in claim 1, Features: In step 2, the data collection method of the rail surface irregularity within 3m of the rail welding joint in the abnormal vibration section is realized by combining a 1m ruler with a feeler gauge, specifically: Before measurement, a tape measure is used to measure the starting and ending positions of the 3m range of the rail welding joint, and a mark is made every 0.5m; then the track surface unevenness data of 5 sections of 1m rail are measured from left to right. The starting points of the 5 sections of 1m rail are the left end of the 3m range and every 0.5m to the right, thereby obtaining 5 1m rail surface unevenness data; then the data splicing method is used to obtain the track surface unevenness data within the 3m range of the rail welding joint through 5 consecutive 1m track surface unevenness data.

3. A method for grinding uneven rail surfaces within 3m of a high-speed railway rail weld joint as claimed in claim 1, Features: In step 2, the data collection method of the rail surface unevenness within 3m of the rail welding joint in the abnormal vibration section is realized by a rail straightness measuring instrument.

4. A method for grinding uneven rail surfaces within 3m of a high-speed railway rail weld joint as claimed in claim 1, Features: In step 3, with the rail welding joint as the center, a rail profile measuring instrument is used to collect rail profile data for every half-sleeper interval within 3m of the rail welding joint, and photos are taken to record the rail surface status and light band width.

5. A method for grinding uneven rail surfaces within 3m of a high-speed railway rail weld joint as claimed in claim 1, Features: In step 4, the rail surface unevenness data analysis method is: according to the rail surface straightness, it is classified into unqualified and qualified. Whether the rail surface unevenness is qualified is determined according to the following limit standards: a. The straightness limit of any 1m rail surface unevenness data within 3m of the rail welding joint is 0.2mm; b. The straightness limit of the 3m rail surface unevenness data of the rail welding joint is -0.2mm~0.6mm; If the collected rail surface unevenness data does not meet any of the above points, it will be judged as an unqualified rail welding joint.

6. A method for grinding uneven rail surfaces within 3m of a high-speed railway rail weld joint as claimed in claim 1, Features: In step 6, a straightness measuring instrument is used to inspect the unevenness of the rail surface within 3m of the rail welding joint to ensure that it meets the limit standard in step 4; at the same time, the rail profile within the grinding range is inspected to ensure that the deviation between it and the rail profile in the ungrinded area is less than 0.5mm at the rail head of -15 to 25mm, and one inspection is carried out for each half sleeper.

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