A control method to ensure straight steel output in each pass of rail rolling

Abstract

This invention relates to a control method for ensuring the straightness of rail exiting the rolling mill in each pass, comprising the following steps: 1) dividing the pass area of ​​the rail head, web, and bottom corresponding to each pass of the universal rolling mill according to a pre-set roll gap value, and calculating the roll area of ​​each part corresponding to each pass; 2) calculating the elongation coefficient of each part of the rail corresponding to each pass; 3) predicting whether the rail exits straight; 4) if the straightness requirement is not met, reallocating the roll gap value until the requirement is met. This invention calculates and allocates the elongation coefficient of each part of the rail corresponding to each pass of the universal rolling mill, ensuring the straightness of the rail exiting the rolling mill by controlling the difference in the metal elongation coefficient of each part of the rail head, web, and bottom within a set range.

Description

Technical Field

[0001] This invention relates to the field of rail rolling technology, and in particular to a control method for ensuring the straightness of steel output in each pass of rail rolling. Background Technology

[0002] A rail consists of three parts: rail head 1, rail web 2, and rail base 3 (e.g., rail head 1, rail web 2, and rail base 3). Figure 1 (As shown). The rail head is the part of the rail that contacts the wheel, and the contact surface is called the rail surface; the rail web is the connecting part between the rail head and the rail base, and the rail base is the main load-bearing part of the rail, with a large width and bottom area.

[0003] Currently, the mainstream rolling method for steel rails is the universal rolling mill method. The main frame of the universal rolling mill consists of a pair of main rolls and a pair of horizontal rolls. The axes of the four rolls are in a plane, with the horizontal rolls being the driving rolls and the vertical rolls being the driven rolls, allowing for simultaneous processing of all four sides of the rolled material. When rolling rails using the universal rolling method, two billet mills are used for roughing. The basic production process is as follows: (1) After heating and descaling the rectangular continuous casting billet, it is rolled by the first billet mill (i.e., BD1 mill, usually a two-roll reversible billet mill); (2) The first billet mill rolls the billet into a hat-shaped piece and then sends it to the second billet mill (i.e., BD2 mill, usually a two-roll reversible billet mill) for rolling; (3) The second billet mill rolls the hat-shaped piece into the prototype of the rail and then sends it to the universal mill for rolling after descaling; (4) After rolling and descaling by the universal roughing mill, it is sent to the universal intermediate mill for rolling. The dimensions and shape of the cross-section of the rolled piece are close to those of the finished rail; (5) After rolling by the universal intermediate mill, it is sent to the universal finishing mill for rolling, thus completing the rail rolling process.

[0004] For newly designed rail products, when rolling them in a universal rolling mill, trial rolling is generally performed directly based on the pre-designed roll pass and the roll gaps of each rolling mill unit preset based on experience. However, due to inaccurate parameter settings, the rolled piece often exhibits upward tilting or lateral deviation upon exiting the mill, which can even lead to equipment collisions and subsequent equipment and safety accidents. Based on the above issues, Summary of the Invention

[0005] This invention provides a control method to ensure the straightness of steel rail exiting each pass of the rolling mill. The method calculates and distributes the elongation coefficients of each part of the rail corresponding to the roll pass of the universal rolling mill. By controlling the difference in the metal elongation coefficients of the rail head, rail web, and rail bottom of each pass within a set range, the method ensures that the rail exits straight and does not collide with the equipment.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A method for controlling the straightness of steel output in each pass of rail rolling includes the following steps:

[0008] 1) Based on the pre-set roll gap value, divide the pass area of ​​each part of the rail head, rail web and rail bottom corresponding to each pass of the universal rolling mill, and calculate the pass area of ​​each part corresponding to each pass.

[0009] 2) Based on the die area of ​​each part corresponding to each pass obtained in step 1), calculate the elongation coefficient of each part of the rail corresponding to each pass. The elongation coefficient of each part of the rail in each pass = die area of ​​the corresponding part of the previous pass ÷ die area of ​​the corresponding part of the subsequent pass.

[0010] 3) Based on the elongation coefficients of each part of the rail in each pass calculated in step 2), predict whether the rail will be straight when it exits the steel. That is, if the difference between the maximum and minimum elongation coefficients of the three parts of the rail head, rail web and rail bottom is controlled within the set value, it is determined that the rolled rail can meet the requirement of straight exit.

[0011] 4) If the difference between the maximum and minimum elongation coefficients of the three parts (rail head, rail web, and rail bottom) determined in step 3) is greater than the set value, then the roll gap value is redistributed, and steps 1) to 3) are repeated until it is determined that the requirement of straight steel output can be met.

[0012] Furthermore, in step 3), the value is set to 0.08.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1) Calculate and allocate the elongation coefficients of each part of the rail corresponding to the roll pass of each pass of the universal rolling mill. By controlling the difference in the metal elongation coefficients of each part of the rail head, rail web and rail bottom of each pass within the set range, the rail is ensured to be in a straight state when it exits the steel.

[0015] 2) Effectively controlling the state of steel exiting each pass of rail rolling is conducive to the smooth operation of rail rolling production and prevents safety accidents. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the division of various parts of the rail.

[0017] Figure 2 This is a schematic diagram showing the cross-sectional areas of various parts of the rail corresponding to different rolling passes and roll patterns in an embodiment of the present invention.

[0018] Figure 3 It is the elongation coefficient of each part of the rail during the universal rolling mill in the embodiments of the present invention.

[0019] In the diagram: 1. Rail head 2. Rail web 3. Rail base Detailed Implementation

[0020] Universal rolling (finish rolling) of rails typically employs a three-stand continuous rolling process: the first stand (UR pass) followed by the edge-pressing mill (EF and ER passes, collectively referred to as E passes) and the second stand (UF pass). During universal rolling, the deformation mechanisms of the rail head, web, and base differ significantly, and these parts influence and constrain each other during deformation. If the elongation coefficients of the rail head, web, and base differ too much during universal rolling, it will not only affect the straightness of the rail upon exiting the mill but also impact the mechanical properties of the finished rail due to residual stress.

[0021] The present invention provides a control method for ensuring straight steel output in each pass of rail rolling, comprising the following steps:

[0022] 1) Based on the pre-set roll gap value, divide the pass area of ​​each part of the rail head, rail web and rail bottom corresponding to each pass of the universal rolling mill, and calculate the pass area of ​​each part corresponding to each pass.

[0023] 2) Based on the die area of ​​each part corresponding to each pass obtained in step 1), calculate the elongation coefficient of each part of the rail corresponding to each pass. The elongation coefficient of each part of the rail in each pass = die area of ​​the corresponding part of the previous pass ÷ die area of ​​the corresponding part of the subsequent pass.

[0024] 3) Based on the elongation coefficients of each part of the rail in each pass calculated in step 2), predict whether the rail will be straight when it exits the steel. That is, if the difference between the maximum and minimum elongation coefficients of the three parts of the rail head, rail web and rail bottom is controlled within the set value, it is determined that the rolled rail can meet the requirement of straight exit.

[0025] 4) If the difference between the maximum and minimum elongation coefficients of the three parts (rail head, rail web, and rail bottom) determined in step 3) is greater than the set value, then the roll gap value is redistributed, and steps 1) to 3) are repeated until it is determined that the requirement of straight steel output can be met.

[0026] Furthermore, in step 3), the value is set to 0.08.

[0027] The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028]

Example

[0029] In this embodiment, to ensure that the steel exits straight in each rolling pass of the newly designed rail, the specific operation steps are as follows:

[0030] 1) Based on the pre-set roll gap value, divide the pass area for each part of the rail head, web, and bottom during universal rolling mill operation, and calculate the pass area for each part in each pass. Figure 2 And as shown in Table 1;

[0031] 2) Based on the bore area of ​​each section corresponding to each pass obtained in step 1), calculate the elongation coefficient of each section of the rail corresponding to each pass (e.g., ...). Figure 3 (As shown in Table 1), the elongation coefficient of each part of the rail in each pass = the area of ​​the corresponding part of the previous pass ÷ the area of ​​the corresponding part of the subsequent pass.

[0032] Table 1. Cross-sectional area of ​​various parts of the rail and elongation coefficient of various parts for each track.

[0033]

[0034]

[0035] 3) Based on the elongation coefficient of each part of the rail in each pass calculated in step 2), predict whether the rail exits straight.

[0036] In this embodiment, the difference between the maximum and minimum elongation coefficients of the three parts—rail head, rail web, and rail bottom—are all controlled within the set value (0.08) in the same rolling pass. Therefore, it is determined that the rails in each rolling pass are straight and there will be no upward tilting or left-right deviation of the rolled piece when it exits the rolling mill, effectively avoiding accidents caused by the rolled piece colliding with the equipment.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A control method for ensuring straight steel output in each pass of rail rolling, characterized in that, Includes the following steps: 1) Based on the pre-set roll gap value, divide the pass area of ​​each part of the rail head, rail web and rail bottom corresponding to each pass of the universal rolling mill, and calculate the pass area of ​​each part corresponding to each pass. 2) Based on the die area of ​​each part corresponding to each pass obtained in step 1), calculate the elongation coefficient of each part of the rail corresponding to each pass. The elongation coefficient of each part of the rail in each pass = die area of ​​the corresponding part of the previous pass ÷ die area of ​​the corresponding part of the subsequent pass. 3) Based on the elongation coefficients of each part of the rail in each pass calculated in step 2), predict whether the rail will be straight when it exits the steel. That is, if the difference between the maximum and minimum elongation coefficients of the three parts of the rail head, rail web and rail bottom is controlled within the set value, it is determined that the rolled rail can meet the requirement of straight exit. 4) If the difference between the maximum and minimum elongation coefficients of the three parts (rail head, rail web, and rail bottom) determined in step 3) is greater than the set value, then the roll gap value is redistributed, and steps 1) to 3) are repeated until it is determined that the requirement of straight steel output can be met.

2. The control method for ensuring straight steel output in each pass of rail rolling according to claim 1, characterized in that, In step 3), the value is set to 0.08.

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