Control method for guaranteeing straightness of steel tapping of steel rail rolling in each pass

Abstract

The invention relates to a control method for ensuring straightness of tapping of each pass of steel rail rolling, which comprises the following steps of: 1) dividing hole pattern surface domains of each part of a rail head, a rail waist and a rail bottom of a steel rail corresponding to each pass during rolling of a universal rolling mill according to a preset roll gap value, and calculating the hole pattern area of each part corresponding to each pass; 2) calculating the extension coefficient of each part of the steel rail corresponding to each pass; 3) pre-judging whether the steel rail is in a straight state or not during tapping; and 4) when judging that the straightness requirement is not met, redistributing the roll gap value until the requirement is met. According to the method, the extension coefficient of each part of the steel rail corresponding to each pass of roller pass of the universal rolling mill is calculated and distributed, and the steel rail tapping straightness is ensured by controlling the difference value of the metal extension coefficients of each part of each pass of rail head, rail waist and rail bottom within a set range.

Description

Technical Field

[0001] The invention relates to the technical field of rail rolling, and in particular to a control method for ensuring that each pass of rail rolling produces straight steel. Background Art

[0002] The rail consists of three parts: rail head 1, rail waist 2 and rail bottom 3 (such as Figure 1 The rail head is the part of the track that contacts the wheel, and the contact surface is called the rail surface; the rail waist is the connecting part between the rail head and the rail bottom, and the rail bottom is the main load-bearing part of the track, with a larger width and bottom area.

[0003] The mainstream rolling method for rails is the universal rolling mill. The main frame of the universal rolling mill consists of a pair of main rollers and a pair of horizontal rollers. The axes of the four rollers are in the same plane. The horizontal rollers are active rollers and the vertical rollers are driven rollers. The four surfaces of the rolling body can be processed at the same time. When rolling rails using the universal rolling method, two slab mills are used for rough rolling. The basic production process is as follows: (1) After heating and descaling the rectangular continuous casting billet, it is rolled by the first slab mill (i.e., BD1 mill, which is usually a two-roller reversible slab mill); (2) The first slab mill rolls the cast billet into a hat-shaped piece through the hat-shaped rolling mill and then sends it to the second slab mill (i.e., BD2 mill, which is usually a two-roller reversible slab mill) for rolling; (3) The second slab mill rolls the hat-shaped piece into the prototype of the rail through the rail-shaped hole, which is then sent to the universal mill for rolling after descaling; (4) After rolling and descaling by the universal rough rolling mill, it is sent to the universal intermediate mill for rolling. After rolling, the size and shape of the cross-section of the 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 rolling process of the rail.

[0004] When rolling newly designed rail products in a universal rolling mill, test rolling is usually carried out directly according to the pre-designed hole type and the roll gap of each rolling unit preset based on experience. Due to inaccurate parameter settings, the rolled products often warp up or deviate left and right when leaving the rolling mill. In serious cases, they may even hit the equipment, leading to equipment and safety accidents. Based on the above problems, Summary of the invention

[0005] The present invention provides a control method for ensuring that the steel is straight when each pass of rail rolling is conducted. The elongation coefficients of the roller pass profiles of each pass of a universal rolling mill corresponding to each part of the rail are calculated and allocated. By controlling the difference in the metal elongation coefficients of the rail head, rail waist and rail bottom of each pass within a set range, the steel is ensured to be straight when the rail is conducted and will not hit the equipment.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A control method for ensuring that each pass of rail rolling produces straight steel comprises the following steps:

[0008] 1) According to the preset roll gap value, the hole profile area of ​​each part of the rail head, rail waist and rail bottom corresponding to each pass of the universal rolling mill is divided, and the hole profile area corresponding to each part of each pass is calculated;

[0009] 2) According to the hole area of ​​each part corresponding to each pass obtained in step 1), the elongation coefficient of each part of the rail corresponding to each pass is calculated, and the elongation coefficient of each part of the rail at each pass = the hole area of ​​the corresponding part of the rolled piece at the previous pass ÷ the hole area of ​​the corresponding part of the rolled piece at the next pass;

[0010] 3) According to the elongation coefficients of each part of each rail of each pass calculated in step 2), it is predicted whether the rail is in a straight state when it is tapped; that is, when the difference between the maximum elongation coefficient and the minimum elongation coefficient of the three parts of the rail head, rail waist and rail bottom is controlled within the set value, it is determined that the rail after rolling can meet the requirement of straightness when tapped;

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

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

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1) Calculate and distribute the elongation coefficients of various parts of the rail corresponding to the roller pass of each pass of the universal rolling mill, and control the difference of the metal elongation coefficients of the rail head, rail waist and rail bottom of each pass within the set range to ensure that the rail is in a straight state when it is tapped;

[0015] 2) Effectively controlling the state of steel being tapped at each pass of rail rolling is beneficial to the smooth progress of rail rolling production and prevents safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0018] Figure 3 It is the elongation coefficient of each part of the rail when it is rolled in the universal rolling mill in the embodiment of the present invention.

[0019] In the figure: 1. Rail head 2. Rail waist 3. Rail bottom DETAILED DESCRIPTION

[0020] Universal rolling mill rolling (finishing rolling) of rails usually adopts three-stand continuous rolling, the first universal rolling mill UR pass - edge rolling mill EF pass and ER pass (collectively referred to as E pass) - the second universal rolling mill UF pass; during the rolling process of the universal rolling mill, the deformation mechanism of the rail head, rail waist and rail bottom is quite different, and the deformation of each part affects and restrains each other. If the elongation coefficient of the rail head, rail waist and rail bottom is too different during the universal rolling process, it will not only affect the straight state of the rail when tapping, but also affect the mechanical properties of the finished rail due to residual stress.

[0021] The control method for ensuring that each pass of rail rolling produces straight steel comprises the following steps:

[0022] 1) According to the preset roll gap value, the hole profile area of ​​each part of the rail head, rail waist and rail bottom corresponding to each pass of the universal rolling mill is divided, and the hole profile area corresponding to each part of each pass is calculated;

[0023] 2) According to the hole area of ​​each part corresponding to each pass obtained in step 1), the elongation coefficient of each part of the rail corresponding to each pass is calculated, and the elongation coefficient of each part of the rail at each pass = the hole area of ​​the corresponding part of the rolled piece at the previous pass ÷ the hole area of ​​the corresponding part of the rolled piece at the next pass;

[0024] 3) According to the elongation coefficients of each part of each rail of each pass calculated in step 2), it is predicted whether the rail is in a straight state when it is tapped; that is, when the difference between the maximum elongation coefficient and the minimum elongation coefficient of the three parts of the rail head, rail waist and rail bottom is controlled within the set value, it is determined that the rail after rolling can meet the requirement of straightness when tapped;

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

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

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

[0028] [Example]

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

[0030] 1) According to the preset roll gap value, divide the hole area of ​​each pass corresponding to the rail head, rail waist and rail bottom of the universal rolling mill, and calculate the hole area of ​​each pass corresponding to each part, such as Figure 2 As shown in Table 1;

[0031] 2) According to the hole area of ​​each part of each pass obtained in step 1), calculate the elongation coefficient of each part of the rail corresponding to each pass (such as Figure 3 As shown in Table 1), the elongation coefficient of each part of each pass of the rail = the hole area of ​​the corresponding part of the previous pass rolled piece ÷ the hole area of ​​the corresponding part of the next pass rolled piece;

[0032] Table 1 Cross-sectional area of ​​each part of the rail and elongation coefficient of each part of each pass

[0033]

[0034]

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

[0036] In this embodiment, in the same pass, the difference between the maximum value and the minimum value of the elongation coefficient of the three parts of the rail head, rail waist and rail bottom is controlled within the set value (0.08). Therefore, it is determined that the rails are straight in each rolling pass, and the rolled piece will not warp up or deviate to the left or right when leaving the rolling mill, effectively avoiding the accident of the rolled piece hitting the equipment.

[0037] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A control method for ensuring that each pass of rail rolling produces straight steel, characterized in that: The steps include: 1) According to the preset roll gap value, the hole profile area of ​​each part of the rail head, rail waist and rail bottom corresponding to each pass of the universal rolling mill is divided, and the hole profile area corresponding to each part of each pass is calculated; 2) According to the hole area of ​​each part corresponding to each pass obtained in step 1), the elongation coefficient of each part of the rail corresponding to each pass is calculated, and the elongation coefficient of each part of the rail at each pass = the hole area of ​​the corresponding part of the rolled piece at the previous pass ÷ the hole area of ​​the corresponding part of the rolled piece at the next pass; 3) According to the elongation coefficients of each part of each rail of each pass calculated in step 2), it is predicted whether the rail is in a straight state when it is tapped; that is, when the difference between the maximum elongation coefficient and the minimum elongation coefficient of the three parts of the rail head, rail waist and rail bottom is controlled within the set value, it is determined that the rail after rolling can meet the requirement of straightness when tapped; 4) If the difference between the maximum and minimum elongation coefficients of the three parts of the rail head, rail waist and rail bottom determined in step 3) is greater than the set value, the roll gap value is reallocated, and then steps 1) to 3) are repeated until it is determined that the requirement of steel straightness can be met.

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

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