A method and device for controlling the tail size during the rail rolling process and a rail

Abstract

The present application discloses a method and device for controlling the tail size during rail rolling and a rail. Among them, the rail is rolled by a universal rolling mill, and the universal rolling mill includes a roughing mill, an edging mill, and a finishing mill. During the rail rolling process, the rail to be rolled sequentially passes through the roughing mill, the edging mill, and the finishing mill. The method includes: when rolling the rail, obtaining a first countdown time for the tail of the rail to be rolled to be rolled by the roughing mill; when the first countdown time is less than or equal to a set time threshold, reducing the rolling speed of the roughing mill for rolling the rail to be rolled according to a set speed reduction ratio, so as to reduce the size fluctuation when the tail of the rail to be rolled is rolled by the roughing mill. Through the technical solution of the present application, the tail size during rail rolling can be controlled, and the problem of tail fluctuation during rail production can be alleviated.

Description

Technical Field

[0001] This application belongs to the field of iron and steel metallurgy production and manufacturing, and particularly relates to a method and device for controlling the tail size during rail rolling and a rail. Background Art

[0002] In the field of rail production and processing, the mainstream is to process rails through universal rolling mills so that their dimensions can reach the ideal range. However, in some cases, the dimensions of the tail during rail rolling will fluctuate, and now how to control the dimensions of the rail tail has become an urgent problem to be solved. Summary of the Invention

[0003] Embodiments of this application provide a method and device for controlling the tail size during rail rolling and a rail, which can further control the tail size during rail rolling and alleviate the problem of tail fluctuations during rail production.

[0004] Other features and advantages of this application will become apparent through the following detailed description, or be learned in part through the practice of this application.

[0005] According to the first aspect of the embodiments of this application, a method for controlling the tail size during rail rolling is provided. The rail is rolled through a universal rolling mill, and the universal rolling mill includes a roughing mill, an edging mill, and a finishing mill. During rail rolling, the rail to be rolled sequentially passes through the roughing mill, the edging mill, and the finishing mill. The method includes: when rolling the rail, obtaining a first countdown time when the tail of the rail to be rolled is rolled by the roughing mill; when the first countdown time is less than or equal to a set time threshold, reducing the rolling speed of the roughing mill for rolling the rail to be rolled according to a set speed reduction ratio, so as to reduce the size fluctuation when the tail of the rail to be rolled is rolled by the roughing mill.

[0006] In some embodiments of this application, based on the foregoing solution, the method further includes: obtaining a second countdown time when the tail of the rail to be rolled is rolled by the edging mill; when the second countdown time is less than or equal to the set time threshold, reducing the rolling speed of the edging mill for rolling the rail to be rolled according to the set speed reduction ratio, so as to reduce the size fluctuation when the tail of the rail to be rolled is rolled by the edging mill.

[0007] In some embodiments of this application, based on the foregoing solution, obtaining the first countdown time when the tail of the rail to be rolled is rolled by the roughing mill includes: in response to detecting that the rail to be rolled leaves the hot detection device of the universal rolling mill, obtaining the first countdown time when the tail of the rail to be rolled is rolled by the roughing mill.

[0008] In some embodiments of this application, based on the foregoing solution, the set time threshold is 0.6S - 0.9S.

[0009] In some embodiments of the present application, based on the foregoing solution, the method further includes: the set speed reduction ratio is 28% - 32%.

[0010] In some embodiments of the present application, based on the foregoing solution, the method further includes: when the type of the steel rail to be rolled is U71MnG, when the first countdown time is less than or equal to 0.8S, at a speed reduction ratio of 30%, the rolling speed of the rough rolling mill for rolling the steel rail to be rolled is reduced from 3.1m / s to 2.2m / s, and the acceleration of the steel rail to be rolled when passing through the rough rolling mill is reduced from 2m / s2 to 1.4m / s2.

[0011] In some embodiments of the present application, based on the foregoing solution, the method further includes: when the type of the steel rail to be rolled is U71MnG, when the first countdown time is less than or equal to 0.7S, at a speed reduction ratio of 30%, the rolling speed of the rough rolling mill for rolling the steel rail to be rolled is reduced from 3.3m / s to 2.3m / s, and the acceleration of the steel rail to be rolled when passing through the rough rolling mill is reduced from 2.1m / s2 to 1.47m / s2.

[0012] In some embodiments of the present application, based on the foregoing solution, the method further includes: when the type of the steel rail to be rolled is U75V, when the first countdown time is less than or equal to 0.8S, at a speed reduction ratio of 30%, the rolling speed of the rough rolling mill for rolling the steel rail to be rolled is reduced from 3.5m / s to 2.38m / s, and the acceleration of the steel rail to be rolled when passing through the rough rolling mill is reduced from 2.3m / s2 to 1.56m / s2.

[0013] In the present application, by obtaining the first countdown time, when the first countdown time is less than or equal to the set time threshold, at the set speed reduction ratio, reducing the rolling speed of the rough rolling mill can effectively control the tail size during the rail rolling process and alleviate the problem of fluctuations in the tail during the production of the rail.

[0014] According to the second aspect of the embodiments of the present application, there is provided a device for controlling the tail size during the rail rolling process, the device includes one or more processors and one or more memories, and at least one program code is stored in the one or more memories, and the at least one program code is loaded and executed by the one or more processors to implement the method as described in the first aspect of the embodiments of the present application.

[0015] According to the third aspect of the embodiments of the present application, there is provided a steel rail, and the steel rail is rolled by using the method as described in the first aspect of the embodiments of the present application.

[0016] For the beneficial effects of the embodiments in the above second to third aspects, reference may be made to the beneficial effects of the above first aspect and its various embodiments, which will not be elaborated here.

[0017] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application. Obviously, the accompanying drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0019] Figure 1 Shows the pass diagram of a rolling mill to which the technical solution of the embodiment of this application can be applied;

[0020] Figure 2 Shows the rail height change diagram in the embodiment of this application;

[0021] Figure 3 Shows the speed change diagram of the rail tail at the edger before deceleration in the embodiment of this application;

[0022] Figure 4 Shows the speed change diagram of the rail tail at the edger after deceleration in the embodiment of this application;

[0023] Figure 5 Shows the flowchart of the tail size control method during the rail rolling process in the embodiment of this application;

[0024] Figure 6 Shows another flowchart of the tail size control method during the rail rolling process in the embodiment of this application;

[0025] Figure 7 Shows the structural schematic diagram of the tail size control device during the rail rolling process in the embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0027] In addition, the described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present application. However, those skilled in the art will realize that the technical solutions of the present application may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be employed. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the present application.

[0028] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0029] The flowcharts shown in the drawings are only illustrative and do not necessarily include all the content and operations / steps, nor are they necessarily executed in the described order. For example, some operations / steps may be decomposed, while some operations / steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0030] To enable those skilled in the art to better understand the present application, the following will be briefly described in conjunction with Figure 1 and Figure 2 for a simple explanation.

[0031] Referring to Figure 1 , a pass diagram of a rolling mill to which the technical solution of the embodiment of the present application can be applied is shown.

[0032] As Figure 1 shown, the pass diagram of the rolling mill includes three roll diagrams, which are, from left to right, the roughing mill roll diagram, the edging mill roll diagram, and the finishing mill roll diagram. The roughing mill is used for the primary processing of the rail to be rolled, the edging mill is used for the secondary processing of the rail to be rolled, and the finishing mill is used for the finishing processing of the rail to be rolled. During the processing, deformation zones will be generated at both ends of the rail to be rolled. When the deformation zones at the tail of the rail to be rolled pass through the roughing mill and the edging mill, since the area of the deformation zone is small and the moment of inertia of the roughing mill and the edging mill remains unchanged, the speed of the roughing mill and the edging mill becomes faster. Because the speed of the roughing mill and the edging mill becomes faster, an instantaneous stacking relationship of the rail is caused, resulting in fluctuations in the size of the rail tail.

[0033] Furthermore, referring to Figure 2 , a diagram of the rail height change in the embodiment of the present application is shown.

[0034] As Figure 2As shown, it is a graph of the rail height change of a 100-meter rail to be rolled after being processed by a rolling mill. From Figure 2 it can be known that the ideal size of the rail to be rolled is 176 mm. There is a bump at 3.8 meters from the tail of the rail (i.e., the size at the tail fluctuates). The rail height at this point is 0.5 mm - 0.6 mm higher than the ideal size. There is a bump at 7.6 meters from the tail of the rail (i.e., the size at the tail fluctuates). The rail height at this point is 0.3 mm - 0.4 mm higher than the ideal size.

[0035] Combined with Figure 1 and Figure 2 it can be obtained that the reason for the size fluctuation at the tail of the rail is that the rolling speeds of the roughing mill and the edging mill become faster. Therefore, by controlling the rolling speeds of the roughing mill and the edging mill, the size fluctuation at the tail of the rail can be alleviated.

[0036] The implementation details of the technical solution of the embodiments of the present application are elaborated in detail below:

[0037] Figure 3 It shows the speed change graph of the rail tail at the edging mill before speed reduction in the embodiments of the present application. As Figure 3 shown, after the rail to be rolled enters the rolling mill, the speed of the rail tail is generally in a stable state, but there will be a sudden change in speed locally, and it gradually returns to stability after the sudden change in speed. Specifically, in the time interval from 14:22:25.5 to 14:22:26.0, there is a large sudden change in speed, and the duration of the sudden change in speed is extremely short. After analysis, it can be obtained that the time point of the sudden change in speed is consistent with the time point when the rail tail of the rail to be rolled enters the rolling mill. Therefore, it can be determined that the reason for the sudden change in rolling speed is related to the entry of the rail tail of the rail to be rolled into the rolling mill.

[0038] It can be seen that in the present application, the sudden change in the speed of the rail tail will cause the size fluctuation of the rail tail.

[0039] Figure 4 It shows the speed change graph of the rail tail at the edging mill after speed reduction in the embodiments of the present application. Referring to Figure 3 , since the sudden change in the speed of the rail tail will cause the size fluctuation of the rail tail, the rolling speed is reduced. As Figure 4 shown, after the rail to be rolled enters the rolling mill, the speed of the rail tail is generally in a stable state, but there will be a sudden change in speed locally, and it gradually returns to stability after the sudden change in speed. Specifically, in the time interval from 13:15:09.0 to 13:15:09.5, there is a small sudden change in speed. After analysis, it can be obtained that since the amplitude of the sudden change in the speed of the rail tail becomes smaller, the fluctuation of the rail tail size caused by the sudden change in the speed of the rail tail is also correspondingly reduced, and the problem of size fluctuation at the tail of the rail during production can be alleviated.

[0040] It can be seen that in the present application, by reducing the rolling speed, the amplitude of the sudden change in the speed of the rail tail can be reduced, thereby reducing the fluctuation of the rail tail size caused by the sudden change in speed.

[0041] Figure 5 The flowchart of the method for controlling the tail size during the rail rolling process in the embodiment of the present application is shown. Among them, the rail is rolled by a universal rolling mill, and the universal rolling mill includes a roughing mill, an edging mill, and a finishing mill. During the rail rolling process, the rail to be rolled passes through the roughing mill, the edging mill, and the finishing mill in sequence. The method for controlling the tail size during the rail rolling process can be executed by a device with computing and processing capabilities, such as the device for controlling the tail size during the rail rolling process. Refer to Figure 3 As shown, the method for controlling the tail size during the rail rolling process at least includes steps 510 to 530, which are introduced in detail as follows:

[0042] Step 510, when rolling the rail, obtain the first countdown time when the tail of the rail to be rolled is rolled by the roughing mill.

[0043] Step 530, when the first countdown time is less than or equal to the set time threshold, reduce the rolling speed of the roughing mill for rolling the rail to be rolled according to the set speed reduction ratio, so as to reduce the size fluctuation when the tail of the rail to be rolled is rolled by the roughing mill.

[0044] Specifically, when rolling the rail, obtain the first countdown time when the tail of the rail to be rolled is rolled by the roughing mill, that is, obtain a period of time before the sudden change in the rolling mill speed as the first countdown time. When the first countdown time is less than or equal to the set time threshold (the time threshold can be 0.6S - 0.9S), that is, during a period of time before the sudden change in the rolling mill speed, reduce the rolling speed of the roughing mill for rolling the rail to be rolled according to the set speed reduction ratio (which can be 28% - 32%). During a period of time before the sudden change in the rolling mill speed, by reducing the rolling speed of the roughing mill, when the tail of the rail to be rolled passes through the roughing mill, the amplitude of the sudden change in the rolling speed of the roughing mill is reduced, that is, the rolling speed of the roughing mill is reduced. By reducing the rolling speed of the roughing mill, the amplitude of the sudden change in the rail tail speed can be reduced, and then the size fluctuation when the tail of the rail to be rolled is rolled by the roughing mill can be reduced.

[0045] For example, when rolling U71MnG steel rails, 0.8 seconds before the tail of the to-be-rolled steel rail enters the roughing mill, the rolling speed of the roughing mill is reduced by 30% from 3.1 m / s to 2.2 m / s. The speed change rate (i.e., acceleration) of the universal mill is reduced from the original 2.0 m / s² to 1.4 m / s², and the speed change is smoother, thereby reducing the size fluctuation of the tail of the to-be-rolled steel rail. The size fluctuation of the tail of the to-be-rolled steel rail is between 0.11 mm and 0.25 mm, with an average of 0.18 mm and a qualification rate of 100%.

[0046] Also, for example, when rolling U71MnG steel rails, 0.7 seconds before the tail of the to-be-rolled steel rail enters the roughing mill, the rolling speed of the roughing mill is reduced by 30% from 3.3 m / s to 2.3 m / s. The speed change rate (i.e., acceleration) of the universal mill is reduced from the original 2.1 m / s² to 1.47 m / s², and the speed change is smoother, thereby reducing the size fluctuation of the tail of the to-be-rolled steel rail. The size fluctuation of the tail of the to-be-rolled steel rail is between 0.14 mm and 0.26 mm, with an average of 0.19 mm and a qualification rate of 100%.

[0047] Also, for example, when rolling U75V steel rails, 0.8 seconds before the tail of the to-be-rolled steel rail enters the roughing mill, the rolling speed of the roughing mill is reduced by 32% from 3.5 m / s to 2.38 m / s. The speed change rate (i.e., acceleration) of the universal mill is reduced from the original 2.3 m / s² to 1.56 m / s², and the speed change is smoother, thereby reducing the size fluctuation of the tail of the to-be-rolled steel rail. The size fluctuation of the tail of the to-be-rolled steel rail is between 0.13 mm and 0.23 mm, with an average of 0.17 mm and a qualification rate of 100%.

[0048] It should be noted that the time threshold and the speed reduction ratio need to be selected according to the specific rolling variety.

[0049] It can be seen that in this application, when the tail of the to-be-rolled steel rail passes through the rolling mill, by reducing the speed of the roughing mill in advance to reduce the acceleration during the sudden change of the roughing mill speed, the amplitude of the sudden change of the speed of the tail of the steel rail is reduced. Therefore, the size fluctuation of the tail of the to-be-rolled steel rail during rolling by the roughing mill can be effectively controlled, and the problem of fluctuation at the tail of the steel rail during the production process can be alleviated.

[0050] Furthermore, in an embodiment of this application, through the thermal detection device, the time when the to-be-rolled steel rail leaves the universal mill can be detected, so the first countdown time for the tail of the to-be-rolled steel rail to be rolled by the roughing mill can be obtained.

[0051] It can be seen that, under further optimization in the embodiments of the present application, the time when the rail to be rolled leaves the universal rolling mill can be accurately determined, so as to accurately obtain the first countdown time when the tail of the rail to be rolled is rolled by the roughing mill, improving the time control accuracy and the accuracy of controlling the fluctuation of the tail of the rail to be rolled.

[0052] In another embodiment of the present application, in order to reduce the rolling speed of the roughing mill for rolling the rail to be rolled, it can also be achieved by executing the solution as Figure 6 shown.

[0053] Figure 6 Another flowchart of the tail size control method in the rail rolling process in the embodiments of the present application is shown. Among them, the rail is rolled by a universal rolling mill, and the universal rolling mill includes a roughing mill, an edging mill, and a finishing mill. During the rail rolling process, the rail to be rolled passes through the roughing mill, the edging mill, and the finishing mill in sequence. The tail size control method in the rail rolling process can be executed by a device with computing and processing functions, such as a tail size control device in the rail rolling process. Referring to Figure 3 shown, the tail size control method in the rail rolling process at least includes steps 610 to 630, which are introduced in detail as follows:

[0054] Step 610, when rolling the rail, obtain the second countdown time when the tail of the rail to be rolled is rolled by the edging mill.

[0055] Step 630, when the second countdown time is less than or equal to the set time threshold, reduce the rolling speed of the edging mill for rolling the rail to be rolled according to the set speed reduction ratio, so as to reduce the size fluctuation when the tail of the rail to be rolled is rolled by the edging mill.

[0056] In order to enable those skilled in the art to better understand the present application, the following will be described in conjunction with Figure 3 and Figure 4 for illustration.

[0057] Specifically, referring to Figure 3 , when rolling the rail, obtain the second countdown time when the tail of the rail to be rolled is rolled by the edging mill, that is, obtain Figure 3 a period of time before the sudden change of the rolling mill speed as the second countdown time. When the second countdown time is less than or equal to the set time threshold (the time threshold can be 0.6S - 0.9S), that is, within Figure 3 a period of time before the sudden change of the rolling mill speed, reduce the rolling speed of the edging mill for rolling the rail to be rolled according to the set speed reduction ratio (which can be 28% - 32%). Referring to Figure 4, before the rolling mill speed changes suddenly for a period of time, by reducing the rolling speed of the edger, when the tail of the to-be-rolled rail passes through the edger, the amplitude of the sudden change in the rolling speed of the edger decreases, that is, the rolling speed of the edger decreases. By reducing the rolling speed of the edger, the amplitude of the sudden change in the speed of the rail tail can be reduced, and then the dimensional fluctuation when the tail of the to-be-rolled rail is rolled by the edger can be reduced.

[0058] It can be seen that in this application, when the tail of the to-be-rolled rail passes through the rolling mill, by reducing the speed of the edger in advance, the acceleration when the speed of the edger changes suddenly is reduced, so as to reduce the amplitude of the sudden change in the speed of the rail tail. Therefore, the dimensional fluctuation when the tail of the to-be-rolled rail is rolled by the edger can be effectively controlled, and the problem of tail fluctuation during the production of the rail can be alleviated.

[0059] Furthermore, in an embodiment of this application, through the thermal inspection device, the time when the to-be-rolled rail leaves the universal rolling mill can be detected, so the second countdown time when the tail of the to-be-rolled rail is rolled by the edger can be obtained.

[0060] It can be seen that under the further optimization in the embodiment of this application, the time when the to-be-rolled rail leaves the universal rolling mill can be accurately determined, so as to accurately obtain the second countdown time when the tail of the to-be-rolled rail is rolled by the edger, improving the time control accuracy and the accuracy of controlling the tail fluctuation of the to-be-rolled rail.

[0061] Figure 7 The structural schematic diagram of the tail size control device during the rail rolling process in the embodiment of this application is shown.

[0062] Based on the same inventive concept, the embodiment of this application also provides a tail size control device during the rail rolling process. Refer to Figure 7 , which shows the structural schematic diagram of the tail size control device during the rail rolling process in the embodiment of this application. The tail size control device during the rail rolling process includes one or more memories 704, one or more processors 702, and at least one computer program (program code) stored on the memory 704 and executable on the processor 702. When the processor 702 executes the computer program, it implements the tail size control method during the rail rolling process as described above.

[0063] Among them, in Figure 7Among them, there is a bus architecture (represented by bus 700). Bus 700 may include any number of interconnected buses and bridges. Bus 700 links together various circuits of one or more processors represented by processor 702 and a memory represented by memory 704. Bus 700 may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, etc., which are well known in the art, and thus will not be further described herein. Bus interface 705 provides an interface between bus 700 and receiver 701 and transmitter 703. Receiver 701 and transmitter 703 may be the same element, i.e., a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 702 is responsible for managing bus 700 and general processing, while memory 704 may be used to store data used by processor 702 when performing operations.

[0064] In this application, a universal rolling mill is also proposed. The universal rolling mill includes a roughing mill, an edging mill, and a finishing mill. During the rail rolling process, the rail to be rolled passes through the roughing mill, the edging mill, and the finishing mill in sequence. The universal rolling mill further includes a tail size control device during the rail rolling process as Figure 7 shown.

[0065] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope and spirit of this application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. In addition, each functional unit may be integrated in one processing unit, or each unit may exist physically alone, or two or more units may be integrated in one unit.

[0066] In several embodiments provided in this application, it should be understood that the disclosed technical content may be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units may be a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other may be through some interfaces, and the indirect couplings or communication connections of units or modules may be in electrical or other forms.

[0067] The unit described as a separation component may or may not be physically separated. The component serving as the control device may or may not be a physical unit, that is, it may be located in one place or may be distributed over multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0068] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media such as USB flash drives, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0069] The above are only the embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A method for controlling the tail size during the rail rolling process, characterized in that The steel rail is rolled by a universal rolling mill, which includes a roughing mill, an edging mill, and a finishing mill. During the steel rail rolling process, the steel rail to be rolled passes through the roughing mill, the edging mill, and the finishing mill in sequence. The method includes: When rolling the steel rail, obtain the first countdown time for the tail of the steel rail to be rolled by the roughing mill; When the first countdown time is less than or equal to the set time threshold, reduce the rolling speed of the roughing mill for rolling the steel rail to be rolled according to the set speed reduction ratio, so as to reduce the dimensional fluctuation when the tail of the steel rail to be rolled is rolled by the roughing mill; The set time threshold is 0.6S - 0.9S; The set speed reduction ratio is 28% - 32%.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the second countdown time for the tail of the steel rail to be rolled by the edging mill; When the second countdown time is less than or equal to the set time threshold, reduce the rolling speed of the edging mill for rolling the steel rail to be rolled according to the set speed reduction ratio, so as to reduce the dimensional fluctuation when the tail of the steel rail to be rolled is rolled by the edging mill.

3. The method according to claim 1, wherein The method further includes: In response to detecting that the steel rail to be rolled leaves the thermal inspection device of the universal rolling mill, obtain the first countdown time for the tail of the steel rail to be rolled by the roughing mill.

4. The method according to claim 1, characterized in that The method further includes: when the type of the rail to be rolled is U71MnG, when the first countdown time is less than or equal to 0.8 s, at a speed reduction ratio of 30%, reducing the rolling speed of the rough rolling mill for rolling the rail to be rolled from 3.1 m / s to 2.2 m / s, and reducing the acceleration of the rail to be rolled when passing through the rough rolling mill from 2 m / s 2 to 1.4 m / s 2 .

5. The method according to claim 1, characterized in that, The method further includes: when the type of the rail to be rolled is U71MnG, when the first countdown time is less than or equal to 0.7S, at a speed reduction ratio of 30%, the rolling speed of the roughing mill for rolling the rail to be rolled is reduced from 3.3m / s to 2.3m / s, and the acceleration of the rail to be rolled when passing through the roughing mill is reduced from 2.1m / s 2 to 1.47m / s 2 .

6. The method according to claim 1, wherein The method further includes: when the type of the rail to be rolled is U75V, when the first countdown time is less than or equal to 0.8 s, at a speed reduction ratio of 32%, reducing the rolling speed of the rough rolling mill for rolling the rail to be rolled from 3.5 m / s to 2.38 m / s, and reducing the acceleration of the rail to be rolled when passing through the rough rolling mill from 2.3 m / s 2 to 1.56 m / s 2 .

7. A tail size control device during the rail rolling process, characterized in that, Comprising one or more processors and one or more memories, at least one program code is stored in the one or more memories, and the at least one program code is loaded and executed by the one or more processors to implement the method according to any one of claims 1 - 6.

8. A steel rail, characterized in that, The steel rail is rolled by using the tail size control method in the steel rail rolling process according to any one of claims 1 - 6.

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