JP2526323B2 - Leveling rolling method and leveling control device in hot rolling - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leveling rolling method and a leveling control device for straightening a lateral bending of a rolled material during rolling in the production of a steel strip in a hot strip mill.

[0002]

2. Description of the Related Art In a hot strip mill, a slab is heated in a heating furnace and the thickness is about 50 mm by a rough rolling mill.
Of the rough rolled material, continuously rolled by a finishing rolling mill train, and wound by a winder to manufacture a hot coil. At this time, in the rough rolled material, lateral bending (camber) may occur at the tip end or the tail end, but this lateral bending lowers the product yield and causes troubles in rolling work. Therefore, it is necessary to correct it.

Although there is no prior art systematically showing a rolling method for correcting the lateral bending of a rough rolled material, this lateral bending is a few stands in the front stage of the finish rolling mill train, and the roll gap of the rolling roll is The rolling rolls are set so as to be different at both ends of the sheet, and the sheet is rolled (abbreviated as leveling rolling in this specification) to be straightened. That is, a rolling operator performs leveling rolling by setting a difference between roll gaps at both ends of a rolling roll (abbreviated as a leveling correction amount in this specification) based on his own experience. However, conventional leveling rolling based on operator's experience,
It was uncertain.

[0004]

SUMMARY OF THE INVENTION The present invention is capable of reliably and accurately correcting lateral bending of a rough rolled material in the production of hot coils in a hot strip mill.
An object is to provide a leveling rolling method and a leveling control device.

[0005]

FIG. 1 is a schematic explanatory view of the method of the present invention. In the present invention, the shape detector 1 is provided on the entry side of the finishing rolling mill train to detect the lateral bending occurrence length L and the lateral bending amount d of the rough rolled material 2. L and d can be read from the chart of the shape detector 1, but can also be directly known as an output item of an image image by using an image processing device, for example.

FIG. 2 is an explanatory view of the leveling correction amount of the present invention. In the leveling rolling, the roll gap between the upper roll and the lower roll is set to, for example, hS at one end of the roll and hL at the other end of the roll. The leveling correction amount is Δh defined by the following equation.

Δh = | hL-hS | According to the findings of the present inventors, if Δh is too large, the rolling of the finish rolling stand will be hindered. Therefore, there is an upper limit for Δh per finish rolling stand. In this specification, the upper limit of this Δh is the maximum allowable leveling correction amount Δh (max)
Say. This Δh (max) can be grasped in advance for each finishing rolling stand.

When the leveling rolling is performed by the finishing rolling stand close to the entry side, each finishing rolling stand on the rear surface can roll a normal rolled material after the lateral bending is corrected. Therefore, it is preferable to perform the leveling rolling at the finishing rolling stand near the entry side.

Therefore, in the present invention, the leveling correction amount is applied to each finishing rolling stand so that the maximum allowable leveling correction amount is sequentially obtained from the entry side finishing rolling stand, for example, F _{1 in} FIG. That is, in FIG. 1, the leveling rolling is carried out until First, the F ₁ reaches the maximum allowable leveling correction amount, if even if the leveling roll leveling correction amount of F ₁ as Delta] h (max) transverse bend can not be corrected, the
Residual lateral bending is corrected by performing leveling rolling at F ₂ , and if lateral bending cannot be corrected even after performing leveling rolling with F ₁ and F ₂ as the maximum allowable leveling correction amounts,
The remaining lateral bending is corrected by leveling rolling at F ₃ . According to the knowledge of the inventors of the present invention, the normal lateral bending of the rough rolling mill is the leveling rolling with _three finishing rolling stands on the entry side in the finishing rolling mill train, that is, F ₁ , F ₂ and F ₃ in FIG. It can be corrected by doing. Therefore, F ₁ , F ₂ , F
An example of performing leveling rolling in ₃ will be described below.

The lateral bending and leveling correction amount corrected by one finish rolling stand are given by the following equation (1). Δh = hf ( d / L, W) (1) where Δh: Leveling correction amount (mm), h: Roll thickness of rolled material on roll exit side, W: Roll width of rolled material , D : amount of lateral bending, L: length of lateral bending occurrence.

Therefore, the finish rolling stands F ₁ , F ₂ , F ₃
The leveling correction amount in is given by the following equations (2) to (4).

Δh ₁ = h ₁ · f ₁ ( d / L, W) ··· (2) Δh ₂ = h ₂ · f ₂ ( d / L, W) ··· (3) Δh ₃ = h ₃ · f ₃ ( d / L, W) (4) Further, Δh ₁ (max) and Δh ₂ (max) which are the maximum allowable leveling correction amounts of the finishing rolling stands F ₁ , F ₂ and F _3. ) Can be set in advance according to the performance of each finishing rolling stand.

In the equation (3), Δh ₁ is Δ
h ₁ in F ₂ stand formula Delta] h ₂ of which was subject to the limitation that (max), and (4) is an expression of Delta] h ₁ (max) a and Delta] h ₂ (max) in the F ₃ stand Delta] h ₃ is there.

In the present invention, L and d of the rough rolled material are detected by the shape detector as described above, and the above (2)
Based on the value of d / L using the equations, (3) and (4),
Leveling control that applies the leveling correction amount to each finishing rolling stand so that the maximum allowable leveling correction amounts Δh ₁ (max) and Δh ₂ (max) are set in advance from the finishing rolling stand on the entry side, and Based on L and d , the occurrence position and the amount of lateral bending of the rough rolled material are known, and FIG.
At the inlet side guides S ₁ , S ₂ , F ₁ , F ₂ , F ₃ ,
A leveling rolling method in hot rolling, characterized by performing side guide control of retracting S ₃ to a position where the laterally curved portion of the rolled material does not contact while the laterally curved portion passes.

FIG. 3 shows an example of a leveling control device for carrying out the leveling rolling of the present invention. The calculation means, for example, the computer 4, is provided with the equations (2), (3) and (4) and Δh ₁ (ma
x) and Δh ₂ (max) are stored in advance. Also, the computer 4 has standard rolling schedules h ₁ , h ₂ , h
₃ and W are stored in advance.

L and d obtained by the image processing device for the lateral bending of the rough rolled material detected by the shape detector 1 are input to the computer 4. The computer 4 performs the following calculation based on the stored information and the input d / L.

(A). Δh ₁ in the F ₁ stand is calculated by the formula (2), and this is transmitted to the rolling control device 5 to set the leveling correction amount of Δh ₁ mm on the rolling roll of the F ₁ stand. The rolling control device 5 is the leveling control means referred to in the present application.

(B). Δh obtained as a result of the calculation in (a) above
_{When 1} exceeds Δh ₁ (max), the information, that is, 6 in FIG. 3 is fed back to the computer 4, and Δh ₂ is calculated by the equation (3).
Is calculated and the values of Δh ₁ (max) and Δh ₂ are transmitted to the rolling control device 5, and the leveling correction amounts of Δh ₁ (max) and Δh ₂ are set in F ₁ and F ₂ , respectively.

(C). Δh obtained as a result of the calculation in (b) above
_{When 2} exceeds Δh ₂ (max), the information, that is, 7 in FIG. 3 is fed back to the computer 4 and Δh ₃ is calculated by the equation (4).
To calculate Δh ₁ (max), Δh ₃ (max) for F ₁ , F ₂ and F ₃ ,
The leveling correction amount of Δh ₃ is set respectively.

[0020] by the above Leveling control means can be such that the permissible maximum leveling correction amount sequentially input in advance from the finishing roll stand entry side, and sets the leveling correction amount to each finish rolling stand.

The leveling control device shown in FIG. 3 further includes side guide control means 3. The side guide control means 3 is
Based on the L and d, and the generation position and lateral bending amount of the lateral curvature of the rough rolled material become known, the F _1, F _2, side guides S ₁ of the inlet side of the F _3, S _2, S ₃ transverse bend Control is performed to retract the side guide to a position where the lateral bending portion of the rolled material does not contact the side guide while the section passes. The distance for retracting S ₁ , S ₂ , and S ₃ and the time from the start of retracting to the side guide resetting may be set individually for F ₁ , F ₂ , and F ₃ or commonly, but F ₁ and It is also possible to calculate the amount of lateral bending correction in F ₂ and set it so as to correspond to the lateral bending after correction.

[0022]

EXAMPLE The above equation (2) is Δh ₁ = h ₁ × {(12 · 100)
· ( D / L) / W}, with a hot strip mill having a F ₁ stand with Δh ₁ (max) of 0.25 mm, d / L = (10
A rough rolled material having a lateral bend of 0 mm / 10,000 mm) was straightened.

Δh ₁ = 24 × {(12 · 100) · (1/1
00) / 1200} = 0.24 mm and Δh ₁ <Δh ₁ (max). Therefore, only the rolling roll of the F ₁ stand was subjected to leveling correction of 0.24 mm and leveling rolling was performed.

The entrance side guide S ₁ of the F ₁ stand is
The setting was S ₁ = W + 110 mm. Since the lateral bending of the rough rolled material was corrected by the F ₁ stand, no special retreat was applied to S ₂ and S ₃ .

Further, since the rolling speed of F ₁ is 1.5 m / sec, the time from the start of retraction of the side guide S ₁ to the resetting was set to 12 seconds. By the above method, the lateral bending of the rough rolled material was corrected, and a hot coil with a small camber could be manufactured.

[0026]

By carrying out the method of the present invention,
Lateral bending of the rough rolled material is reliably and accurately corrected, and a hot coil having excellent dimensional accuracy can be manufactured. Further, by using the apparatus of the present invention, the lateral bending of the rough rolled material is automatically corrected without requiring the operation of the rolling operator, and a hot coil having a small camber and excellent dimensional accuracy can be stably manufactured. Things are possible.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a method of the present invention, FIG. 2 is an explanatory diagram of a leveling correction amount of the present invention, and FIG. 3 is an explanatory diagram of an example of a leveling control device of the present invention.

[Explanation of symbols]

1: Shape detector, 2: Rough rolled material, 3: Side guide control device, 4: Computer, 5: Leveling control device.

Claims (2)

(57) [Claims] 1. A level detector provided on the entrance side of a finishing rolling mill row of a hot strip mill detects a lateral bending occurrence length L and a lateral bending amount d of a rough rolled material, and presets the leveling of a rolling roll. Using the relational expression between the correction amount and the lateral bending correction amount, the leveling correction is performed on each finishing rolling stand based on the value of d / L so that the maximum allowable leveling correction amount is set in advance from the finishing rolling stand on the incoming side. Leveling control to set by applying the amount, and during the passage of the lateral bend,
A leveling rolling method in hot rolling, characterized in that side guide control for retracting the side guide to a position where the rolled material does not contact is performed independently or simultaneously. 2. A shape detector provided on the entrance side of a finishing rolling mill train of a hot strip mill for detecting a lateral bending occurrence length L and a lateral bending amount d of a rough rolled material, and preliminarily inputted finishing rolling stands. Based on the values of L and d input during the operation using the relational expression of the leveling correction amount of the rolling roll and the lateral bending correction amount, the maximum allowable leveling correction amount is input in advance from the finishing rolling stand on the input side. As described above, calculating means for calculating the leveling correction amount of each finishing rolling stand, leveling control means for setting the leveling amount of each finishing rolling stand as instructed by the calculating means, and a side guide while the lateral bending portion passes through. A side guide control means for retracting the rolled material to a position where it does not come into contact, and the leveling control means and the side guide control means operate independently or simultaneously. Characterized in that the Noh, leveling control device in hot rolling.