Full-length quenching process for hot-rolled switch rail

Abstract

According to the full-length quenching process for the hot-rolled switch rail, sectional quenching is adopted, a preheating process is added for the small section of the switch rail with the low temperature, the small section is preheated to a certain temperature, and then rail head full-length quenching is conducted from the tip of the switch rail according to the quenching process. The problems that the hardness of a small section is low and abnormal structures such as martensite easily occur in a traditional quenching process are solved; the section hardness and the microscopic structure of the produced switch rail meet the standard requirements, and the product quality is stable; the material performance is optimized, the production efficiency is improved, and the process adaptability is enhanced; when the quenching inductor is adopted for quenching production, the quenching inductor has the advantages of being high in heating speed, small in workpiece deformation, high in surface quality, easy to control the depth of a hardening layer, high in automation degree and high in adaptability.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical metallurgy, and in particular relates to a full-length quenching process for a hot-rolled point rail. Background Art

[0002] In order to increase the service life of turnout rails in the field of rail transit, the hot-rolled rails need to be quenched over the entire length of the rail head to increase the hardness of the rail head, improve the wear resistance of the rails, and extend the service life of the rails.

[0003] At present, the processing flow of hot-rolled point rails is generally sawing-profiling-normalizing-top adjustment-machining-rail head milling-rail head full-length quenching-top adjustment process steps. Among them, after the rail head of the point rail is quenched, it must meet the requirements of Appendix D: Offline Heat Treatment Technology of Turnout Rail Parts of "Railway Industry Standard of the People's Republic of China TB / T 2344.2-2020". Among them, the depth of the hardened layer of the rail head is a ≥ 8mm, the cross-sectional hardness of the rail head at 2.5mm from the surface is 32-41HRC (U71Mn material), and the cross-sectional hardness of the rail head at 7.5mm from the surface is ≥ 32HRC; the microstructure of the hardened layer should be fine lamellar pearlite, and there should be no martensite, bainite and grain boundary cementite.

[0004] However, the small-section rail head of the pointed rail has a small cross-section size, low quenching induction heating temperature, and fast air jet cooling rate. After heat treatment, abnormal structures such as quenched martensite are very likely to appear, and the hardness of the rail head section is low. The hardness is lower than 32HRC at 7.5mm from the surface. The quality of the existing full-length quenching process of hot-rolled pointed rails is difficult to guarantee. In this regard, the following improved technical solutions are proposed. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a full-length quenching process for a hot-rolled pointed rail, solve the problem that the small section has low hardness and is prone to abnormal structures such as martensite under the traditional quenching process, and ensure the quenching quality of the rail.

[0006] The technical solution adopted by the present invention is: a full-length quenching process for a hot-rolled point rail, and segmented quenching is adopted for the hot-rolled point rail.

[0007] In the above technical solution, the segmentation method is divided into small cross-section and large cross-section.

[0008] In the above technical solution, preferably: the small section is the section position from the tip of the point rail to 35mm of the point rail.

[0009] In any of the above technical solutions, as a further improvement of the present invention: a preheating step is added to the small section.

[0010] In the above technical solution, the preheating temperature of the preheating step is 500-700°C.

[0011] In the aforementioned technical solution, the preheating speed of the preheating step is 400-600 mm / min.

[0012] The present invention further comprises: after preheating, quenching the entire length of the rail head starting from the tip of the pointed rail according to the set process parameters.

[0013] The present invention claims a full-length quenching process for a hot-rolled point rail, comprising the following steps:

[0014] Step 1. Marking: Before full-length quenching of the hot-rolled point rail, mark the large and small section positions of the point rail in sections according to the processing dimensions on the drawing.

[0015] Step 2: Preheating: Preheat from the tip of the point rail to the small section of the point rail.

[0016] Step 3: Full-length quenching: Quench the entire length of the rail head from the tip of the point rail to the heel of the point rail according to the process parameters.

[0017] Step 4: Quality inspection.

[0018] In the above technical solution, preferably: the step 2 uses a quenching inductor for preheating; and the step 3 uses a quenching inductor for full-length quenching.

[0019] In the above technical solution, the small section of step 1 is the section position from the tip of the pointed rail to 35mm of the pointed rail; the preheating temperature of step 2 is 500-700°C.

[0020] The advantages of the present invention compared with the prior art are:

[0021] 1. The cross-sectional hardness and microstructure of the hot-rolled point rail produced by the present invention using a segmented quenching process meet the standard requirements; the problem of low hardness of small sections and easy occurrence of abnormal structures such as martensite under the traditional quenching process is solved, and the quenching quality of the rail is guaranteed.

[0022] 2. The preheating method used for heat treatment during the segmented quenching of the heart rail of the present invention has the technical advantages of improving quenching quality, optimizing material properties, improving production efficiency and enhancing process adaptability; these advantages help to ensure that the heat treatment effect of the heart rail meets the design requirements and improves its service life and reliability.

[0023] 3. The present invention quenches the entire length of the rail head starting from the tip of the point rail according to the set process parameters, which has the technical advantages of improving the strength and hardness of the rail, extending the service life of the rail, optimizing the quenching effect, improving the process efficiency and stability, and adapting to different working conditions. These advantages help to ensure the safety and stability of railway track production and improve the efficiency and quality of railway production operations.

[0024] 4. The step of marking before quenching in the present invention has the advantages of clearly guiding production, improving production efficiency, ensuring product quality, and facilitating quality control and traceability.

[0025] 5. The present invention adopts quenching inductor for quenching, which has the advantages of fast heating speed, small deformation of workpiece, high surface quality, easy control of hardened layer depth, high degree of automation and strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the preheating and quenching process of the 50AT1 (U71Mn) hot-rolled point rail of the present invention;

[0027] Figure 2 This is a schematic diagram of the hardness measurement points of the cross-section of the rail head of the 50AT1 (U71Mn) hot-rolled pointed rail of the present invention;

[0028] Figure 3 This is a metallographic diagram of the 35 mm cross-section structure of 50AT1 (U71Mn) 50AT1 (U71Mn) hot-rolled point rail produced according to the process of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the attached embodiment of the present invention Figure 1-3 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The invention discloses a full-length quenching process for a hot-rolled point rail, wherein the hot-rolled point rail is quenched in sections.

[0031] The proposed segmented quenching design of the present invention can reduce the overall thermal stress and structural stress, thereby reducing quenching distortion; the quenching process parameters, such as quenching temperature, cooling rate, etc., can also be adjusted according to the specific conditions of each segment to further reduce distortion. Segmented quenching can process multiple segments at the same time, or shorten the quenching time of each segment by optimizing process parameters, thereby improving production efficiency. Segmented quenching can reduce production costs by optimizing process parameters, reducing quenching distortion, etc. In addition, segmented quenching can flexibly adjust the number of quenching segments according to actual needs to adapt to different specifications and lengths of pointed rails, further improving production flexibility. Segmented quenching can also make the performance of each segment of material more uniform and consistent, and the quenching process parameters can be adjusted according to actual needs to optimize the performance of the material.

[0032] Therefore, the cross-sectional hardness and microstructure of the hot-rolled point rail produced by the present invention using a segmented quenching process meet the standard requirements; it solves the problem of low hardness of small sections and easy occurrence of abnormal structures such as martensite under the traditional quenching process, and ensures the quenching quality of the rail parts.

[0033] In the above embodiment, (such as Figure 1The segmentation method of the present invention is divided into small section and large section. Small section segmentation usually refers to the segmentation according to the smaller cross-sectional size of the heart rail in the heart rail material or structure. Large section segmentation is the segmentation according to the larger cross-sectional size of the heart rail.

[0034] In any of the above embodiments, preferably: the small section is the 35mm section position from the tip of the point rail to the point rail. The 35mm section position embodiment is applicable to Appendix D of the "Railway Industry Standard of the People's Republic of China TB / T2344.2-2020": Technical requirements for offline heat treatment of turnout rail parts mentioned in the background technology, especially the processing requirements for 50AT1 (U71Mn) hot-rolled point rails.

[0035] In any of the above embodiments, as a further improvement of the present invention, a preheating step is added to the small section. The present invention adopts a preheating method for heat treatment during segmented quenching of the heart rail, which has technical advantages such as improving quenching quality, optimizing material properties, improving production efficiency and enhancing process adaptability; these advantages help to ensure that the heat treatment effect of the heart rail meets the design requirements and improves its service life and reliability. The specific analysis is as follows: In terms of improving quenching quality, preheating can make the heart rail reach a relatively uniform temperature state before quenching, which helps to better control the temperature distribution in the subsequent quenching process, thereby improving the quenching quality. In terms of reducing deformation, preheating can reduce the thermal stress of the heart rail during the quenching process, thereby reducing the risk of quenching deformation, which helps to maintain the geometric shape and dimensional accuracy of the heart rail. In terms of improving hardness, preheating helps the heart rail material to reach the austenitizing temperature more evenly, thereby obtaining a higher hardness after quenching, which is crucial to improving the wear resistance and service life of the heart rail. In terms of improving organizational properties, preheating can promote the organizational transformation inside the heart rail material, so that it forms a more uniform and fine organizational structure after quenching, and this organizational structure helps to improve the strength and toughness of the heart rail. In terms of improving production efficiency, preheating can shorten the time required for the core rail to reach the quenching temperature, thereby improving quenching efficiency, which helps to reduce production cycles and improve production efficiency. In terms of reducing energy consumption, although preheating itself consumes a certain amount of energy, it can improve quenching efficiency and quality, so overall, preheating helps to reduce energy consumption and production costs. In terms of enhancing process adaptability, preheating can enable the core rail to better adapt to the heat treatment requirements under complex working conditions. For example, in the process of segmented quenching, preheating can ensure that each quenching area can reach the required temperature state, thereby achieving a more uniform heat treatment effect. In terms of improving process flexibility, preheating provides more flexibility for the heat treatment of the core rail. For example, the preheating temperature and quenching process parameters can be adjusted according to different material compositions, cross-sectional dimensions and performance requirements to obtain the best heat treatment effect.

[0036] In the above technical solution, the preheating temperature of the preheating step is 500-700°C.

[0037] Embodiment 1: The preheating temperature of the preheating step is 500°C.

[0038] Embodiment 2: The preheating temperature of the preheating step is 600°C.

[0039] Embodiment 3: The preheating temperature of the preheating step is 700°C.

[0040] It should be noted that the technical advantages of the segmented preheating temperature of the heart rail at 500-700°C are mainly reflected in the following aspects. In terms of improving material properties, preheating can improve the hardness and strength of the heart rail, making it have better wear resistance and durability. This is because preheating can change the crystal structure of the heart rail, making it have better strength and toughness, thereby improving the bearing capacity and deformation resistance. In terms of reducing deformation and cracks, during the preheating process, the heart rail gradually heats up, which can evenly remove the surface oxide layer and impurities, reducing deformation and cracks. In terms of extending the service life, through preheating treatment, a layer of higher hardness organizational structure can be formed on the surface of the heart rail to improve its wear resistance, which can not only reduce the occurrence of wear and fatigue cracks, but also extend the service life of the heart rail and reduce the frequency and cost of maintenance and replacement.

[0041] In the above-mentioned embodiment, the preheating speed of the preheating step is 400-600 mm / min.

[0042] Embodiment 1: The preheating speed of the preheating step is 400 mm / min. This speed embodiment corresponds to the aforementioned 50AT1 (U71Mn) point rail 500°C preheating temperature embodiment 1.

[0043] Embodiment 2: The preheating speed of the preheating step is 500 mm / min. This speed embodiment corresponds to the aforementioned 600°C preheating temperature embodiment 2 of the 50AT1 (U71Mn) point rail.

[0044] Embodiment 3: The preheating speed of the preheating step is 600 mm / min. This speed embodiment corresponds to the aforementioned 50AT1 (U71Mn) 700°C preheating temperature embodiment 3.

[0045] It should be noted that in the heart rail preheating step, the technical advantages of controlling the preheating speed at 400-600mm / min are mainly reflected in the following aspects. In terms of optimizing the preheating effect, during the preheating process, the appropriate speed can ensure that the surface temperature of the heart rail is evenly distributed, avoiding local overheating or insufficient cooling, which helps to reduce the thermal stress caused by excessive temperature gradient and reduce the risk of deformation and cracks. In terms of improving production efficiency, the appropriate speed can shorten the preheating time, thereby improving production efficiency. Too fast preheating speed may lead to insufficient preheating, while too slow speed may waste time and energy. The speed range of 400-600mm / min can achieve a faster preheating speed while ensuring the preheating quality. In terms of optimizing the process flow, the moderate preheating speed can make the entire preheating process flow smoother and more efficient, which helps to reduce waiting time and waste in the production process and improve overall production efficiency. In terms of enhancing process stability, the preheating speed is controlled within a certain range, which can reduce the impact of human factors on the preheating effect, which helps to ensure that each preheating can obtain consistent results and improve the stability and reliability of the process. In terms of different working conditions, the preheating speed is moderate and can adapt to the preheating requirements under different working conditions. For example, when the material, size or welding requirements of the core rail change, the preheating speed can be adjusted to maintain the stability of the preheating effect. In terms of protecting equipment safety, the preheating speed is moderate, which can reduce the wear and load of the preheating equipment during the preheating process, which helps to extend the service life of the equipment and reduce maintenance and replacement costs. In terms of improving equipment reliability, the preheating speed is controlled within a certain range to ensure that the equipment maintains a stable operating state during the preheating process, which helps to improve the reliability and safety of the equipment and reduce production interruptions caused by equipment failures.

[0046] The present invention further comprises: after preheating, quenching the entire length of the rail head starting from the tip of the pointed rail according to the set process parameters.

[0047] The present invention starts full-length quenching of the rail head from the tip of the pointed rail according to the set process parameters, and has the technical advantages of improving the strength and hardness of the rail, extending the service life of the rail, optimizing the quenching effect, improving the process efficiency and stability, and adapting to different working conditions. These advantages help to ensure the safety and stability of railway track production and improve the efficiency and quality of railway production and operation. The specific analysis is as follows: In terms of improving the strength and hardness of the rail, the full-length quenching technology strictly controls the quenching temperature and time to obtain a uniform quenching effect from the tip of the pointed rail to the full length of the rail head. This treatment method can significantly improve the strength and hardness of the rail, enabling it to withstand greater loads and impact forces, thereby improving the safety and stability of the rail. In terms of extending the service life of the rail, the full-length quenching technology can reduce the wear and deformation of the rail during long-term use by optimizing the quenching process parameters. This treatment method can significantly extend the service life of the track, reduce the frequency of maintenance and replacement, and thus reduce the cost of railway operation. In terms of optimizing the quenching effect, full-length quenching starting from the tip of the pointed rail can ensure uniform distribution and transfer of heat during the quenching process. This treatment method can avoid uneven organization and performance degradation caused by local overheating or insufficient cooling, thereby obtaining a better quenching effect. In terms of improving process efficiency and stability, the full-length quenching technology uses advanced heat treatment equipment and process parameters to achieve automated and intelligent production processes. This treatment method can improve process efficiency and stability, reduce errors and defective product rates caused by human factors, and thus improve product quality and production efficiency. In terms of adapting to different working conditions, the full-length quenching technology can adjust the quenching process parameters according to different working conditions, such as quenching temperature, time, and cooling medium. This treatment method can ensure that the rails can achieve the best performance under different working conditions and meet the safety and stability requirements of railway operations.

[0048] The present invention claims a full-length quenching process for a hot-rolled point rail, further comprising the following steps:

[0049] Step 1. Marking: Before full-length quenching of the hot-rolled point rail, mark the large and small section positions of the point rail in sections according to the processing dimensions on the drawing.

[0050] The step of marking before quenching of the present invention has the advantages of clearly guiding production, improving production efficiency, ensuring product quality, and facilitating quality control and traceability. The specific analysis is as follows: In terms of ensuring the accuracy of the quenching treatment, through marking, it can be clearly pointed out which parts of the heart rail need to be quenched, which helps the operator to accurately perform the quenching operation and avoid omissions or wrong processing. In terms of providing quenching parameters, the marking usually includes relevant parameters of the quenching process, such as quenching medium, quenching temperature, etc. These parameters are crucial to the effect of the quenching treatment. Through marking, the operator can easily obtain these parameters, thereby ensuring the accuracy and consistency of the quenching treatment. In terms of improving production efficiency and simplifying the operation process, with the guidance of marking, the operator can perform the quenching operation more quickly without frequently consulting relevant information or asking others during the operation. This helps to improve production efficiency and shorten the production cycle. In terms of ensuring product quality, the marking can be specially marked according to special needs such as avoiding overburning and preventing cracks, which helps the operator to take corresponding preventive measures when performing the quenching treatment, thereby avoiding the occurrence of quenching defects. In order to facilitate quality traceability, the labeling usually also includes relevant information about the quenching process, such as the quenching date, operator, etc. This information helps to find the problem, analyze the cause and take corresponding improvement measures in the subsequent quality traceability process. When product quality disputes or safety accidents occur, the labeling can be used as one of the legal bases to prove whether the product has been quenched in accordance with the design requirements.

[0051] Step 2: Preheating: Preheat from the tip of the point rail to the small section of the point rail.

[0052] Step 3: Full-length quenching: Quench the entire length of the rail head from the tip of the point rail to the heel of the point rail according to the process parameters.

[0053] Step 4: Quality inspection: After the rail is quenched, the existing technology is used for quality inspection. The quality inspection results show that the cross-section hardness and microstructure of the pointed rail meet the standard requirements and the quenching quality is stable.

[0054] In the above embodiment, preferably: the step 2 uses a quenching inductor for preheating; and the step 3 uses a quenching inductor for full-length quenching.

[0055] It should be noted that the present invention adopts quenching inductor quenching, which has fast heating speed, small deformation of workpiece, high surface quality, easy control of hardened layer depth, high degree of automation and strong adaptability. The specific reasons are analyzed as follows: In terms of fast heating speed, quenching inductor quenching has fast heating speed, small deformation of workpiece, high surface quality, easy control of hardened layer depth, high degree of automation and strong adaptability. In terms of improving thermal efficiency, the thermal efficiency of induction heating is as high as 60% or more, and most of the energy directly acts on the workpiece, reducing heat loss. In terms of small deformation of workpiece, induction heating makes the surface temperature distribution of workpiece uniform, reduces thermal stress caused by temperature gradient, and thus reduces the risk of workpiece deformation. In terms of rapid cooling, induction quenching usually adopts water spray cooling, and the cooling speed is extremely fast, which helps to reduce the thermal deformation of workpiece during quenching. In terms of high surface quality, the induction heating time is short, oxidation and decarburization are not easy to occur on the surface of the workpiece, and the original quality of the surface of the workpiece is maintained. In terms of uniformity of hardened layer, the hardened layer formed by induction quenching is uniform, with high surface hardness and good wear resistance. In terms of easy control of the depth of the hardened layer, by adjusting the power and heating time of the inductor, the depth of the hardened layer can be accurately controlled to meet different process requirements. In terms of clear demarcation line of the hardened layer depth, the demarcation line between the hardened layer and the hardened layer formed by induction quenching is clear, which is helpful to evaluate the quenching effect. In terms of high degree of automation, induction quenching equipment can be integrated with automated production lines to achieve efficient and continuous quenching operations. In terms of ease of operation, the operation of induction quenching equipment is relatively simple, which reduces the skill requirements for operators. In terms of strong adaptability, induction quenching is suitable for a variety of materials, such as medium carbon steel, medium carbon low alloy steel, etc., and is suitable for a wide range of materials. In terms of the diversity of workpiece shapes, although induction quenching is difficult to make inductors for workpieces with complex shapes, it shows good adaptability for workpieces such as heart rails with regular shapes. In terms of adjustability of process parameters, by adjusting process parameters such as heating power, heating time, cooling method, etc., different quenching requirements can be met.

[0056] In the above embodiment, the small section in step 1 is the section from the tip of the point rail to the 35 mm section of the point rail; the preheating temperature in step 2 is 500-700° C. The technical advantages of this embodiment have been described above and will not be repeated here.

[0057] The design principle of the present invention is as follows: the cross-sectional dimensions of the rail head of the small-section pointed rail are small, the induction heating temperature is low and the air jet cooling rate is fast during direct quenching of the rail head, abnormal structures such as quenched martensite are very likely to appear after heat treatment, and the hardness of the rail head section is low. Therefore, before the hot-rolled pointed rail is quenched over the entire length of the rail head, the small-section of the pointed rail is preheated first, which can increase the quenching temperature of the rail head at the small-section of the pointed rail. At the same time, after the small-section of the rail is preheated, the temperature of the corresponding part of the rail parent material increases. In the subsequent quenching process, the quenching cooling rate of the rail head due to the heat conduction of the parent material slows down, and is assisted by a smaller air jet cooling pressure, which can reduce the cooling rate of the rail head at the small-section of the pointed rail, thereby avoiding the occurrence of abnormal structures such as martensite caused by excessive cooling. This solves the problem of low hardness of the small section and the easy occurrence of abnormal structures such as martensite under the traditional quenching process, and ensures the quenching quality of the rail.

[0058] It should be noted that: the present invention takes the full-length quenched 50AT1 (U71Mn) point rail as an example. Appendix D of TB / T2344.2 stipulates that the depth a of the hardened layer of the rail head of the turnout rail after offline heat treatment is ≥8mm, the cross-sectional hardness of the rail head at 2.5mm from the surface is 32-41HRC, and the cross-sectional hardness of the rail head at 7.5mm from the surface is ≥32HRC.

[0059] If the preheating process is not used, the cross-section hardness test points A1, A2, and A3 of the rail head are Figure 2 As shown in the figure (where the first point A1 is 2.5mm from the surface, and the distances between the other points A2 and A3 are both 2.5mm). If the preheating process is not used, the cross-section hardness test values ​​of the rail head are shown in Table 1 below:

[0060] Table 1: Rail head cross-section hardness

[0061] Sample No. Location A1 A2 A3 1# tread 33.1 31.4 30.5

[0062] After preheating at 500°C (2#), 600°C (3#), and 700°C (4#) respectively, the cross-sectional hardness test values ​​of the rail head are shown in Table 2 below.

[0063] Table 2 Rail head cross section hardness

[0064] Sample No. Location A1 A2 A3 2# tread 34.5 33.1 32.6 3# tread 34.3 33.8 32.4 4# tread 35.1 33.9 33.4

[0065] After the preheating process, the microstructure is pearlite plus a small amount of ferrite. Figure 3 shown.

[0066] It can be seen that the preheating method used for heat treatment during the segmented quenching of the heart rail of the present invention has technical advantages such as improving quenching quality, optimizing material properties, improving production efficiency and enhancing process adaptability; these advantages help to ensure that the heat treatment effect of the heart rail meets the design requirements and improves its service life and reliability.

[0067] In addition, the cross-sectional hardness and microstructure of the hot-rolled point rail produced by the present invention using a segmented quenching process meet the standard requirements; it solves the problem of low hardness of small sections and the easy appearance of abnormal structures such as martensite under the traditional quenching process, and ensures the quenching quality of the rail parts.

[0068] The present invention quenches the entire length of the rail head starting from the tip of the pointed rail according to the set process parameters, and has the technical advantages of improving the strength and hardness of the rail, extending the service life of the rail, optimizing the quenching effect, improving the process efficiency and stability, and adapting to different working conditions. These advantages help to ensure the safety and stability of railway track production and improve the efficiency and quality of railway production operations.

[0069] The step of marking before quenching in the present invention has the advantages of clearly guiding production, improving production efficiency, ensuring product quality, and facilitating quality control and traceability.

[0070] The present invention adopts quenching inductor for quenching, which has the advantages of fast heating speed, small deformation of workpiece, high surface quality, easy control of hardened layer depth, high automation degree and strong adaptability.

[0071] It should be understood that although the present specification is mainly described according to three implementation modes, this description is only for the sake of clarity. Those skilled in the art should also regard the specification as a whole. The technical solutions in this embodiment can also be appropriately arranged and combined to form other implementation modes that can be understood by those skilled in the art.

[0072] The preferred embodiments mentioned in the specification of the present invention are not intended to limit the scope of implementation of the present invention. Therefore, all equivalent changes made to the contents described in the claims of the present invention should be included in the scope of the claims of the present invention. It should be noted that the components and materials used in the above embodiments are commercially available unless otherwise specified.

Claims

1. A full-length quenching process for a hot-rolled point rail, characterized in that: The hot-rolled point rail is subjected to segmented quenching.

2. The full-length quenching process of the hot-rolled point rail according to claim 1, characterized in that: The segmentation method is divided into small sections and large sections.

3. The full-length quenching process of the hot-rolled point rail according to claim 2, characterized in that: The small section is the section position from the tip of the pointed rail to the 35mm section of the pointed rail.

4. The full-length quenching process of the hot-rolled point rail according to claim 2 or 3, characterized in that: A preheating step is added to the small section.

5. The full-length quenching process of the hot-rolled point rail according to claim 4, characterized in that: The preheating temperature of the preheating step is 500-700°C.

6. The full-length quenching process of the hot-rolled point rail according to claim 4, characterized in that: The preheating speed of the preheating step is 400-600 mm / min.

7. The full-length quenching process of the hot-rolled point rail according to claim 4, characterized in that: After preheating, the rail head is quenched along the entire length starting from the tip of the rail according to the set process parameters.

8. The full-length quenching process of the hot-rolled point rail according to claim 1, characterized in that: The steps include: Step 1: Marking: Before full-length quenching of the hot-rolled point rail, mark the large and small section positions of the point rail in sections according to the processing dimensions on the drawing; Step 2: Preheating: preheating from the tip of the point rail to the small section of the point rail; Step 3: Full-length quenching: quench the entire length of the rail head from the tip of the point rail to the heel of the point rail according to the process parameters; Step 4: Quality inspection.

9. The full-length quenching process of the hot-rolled point rail according to claim 8, characterized in that : Step 2 uses a quenching inductor for preheating; Step 3 uses a quenching inductor for full-length quenching.

10. The full-length quenching process of the hot-rolled point rail according to claim 8, characterized in that : The small section of step 1 is the section position from the tip of the pointed rail to the 35mm section of the pointed rail; the preheating temperature of step 2 is 500-700℃.

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