JPH0513002B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a steel plate with a variable thickness in the width direction, the thickness profile of which is variable in the width direction.

[Prior Art] Recently, there is a demand for steel plates with different thicknesses in the width direction, which have different thicknesses in the width direction. As a conventional method for manufacturing such steel plates, a plate rolling mill as shown in FIG. 6 has been used.

In the figure, 1 and 2 are a pair of upper and lower back-up rolls (BR), 3 and 4 are a pair of upper and lower working rolls (WR), respectively, and 5 is a rolled material.

In other words, a method is adopted in which unevenness is added (caliber roll) corresponding to the widthwise thickness variation and pitch necessary for the plate in the axial direction (width direction of the rolled material) of a pair of upper and lower work rolls 3 and 4, and then rolled. It had been. For example, JP-A No. 62-54502 discloses a method of rolling a steel plate with protrusions using a caliber roll whose caliber depth is larger than the maximum value of the protrusion height obtained by rolling. ing.

[Problems to be Solved by the Invention] In the case of the conventional plate rolling mill described above, the upper and lower working rolls are axially fixed at symmetrical upper/lower positions, so that the following problems occur.

(1) Since the caliber shape added to the upper and lower working rolls uniquely determines the thickness change and pitch in the width direction of the steel plate, it is necessary to change the shape of the working roll and caliber to match the specifications of the steel plate.

(2) For the same reason as above, it is not possible to adjust the reduction amount of each part in the width direction of the plate in each rolling pass, which means that uneven processing is repeated in the width direction of the plate, resulting in shape defects (distortion).

An object of the present invention is to provide a method for manufacturing a steel plate with different thicknesses in the width direction, in order to solve the problems in the conventional methods as described above.

[Means for Solving the Problems] The present invention provides a method for manufacturing a steel plate with a variable thickness profile in the width direction using a plate rolling mill, in which the upper and lower work rolls are shifted in the axial direction. This is a method for manufacturing a steel plate having a different thickness in the width direction, using a shift device that can be moved and a work roll having a caliber shape in the axial direction, and shifting the work roll while rolling down between rolling passes.

[Function] In the present invention, a shift device that allows the upper and lower work rolls of a plate rolling mill to shift in the axial direction and a work roll that has a caliber shape in the axial direction are used, and a caliber curve that can be shifted in the width direction is created in advance. to change the rolling reduction amount and roll shift amount.

That is, specifically, as shown in FIG. 1 of the embodiment described later, input information necessary for rolling is inputted to a calculation device,
Since the output of this calculation device is used to shift the work roll as it is rolled between the rolling passes of the plate rolling mill, it is possible to manufacture thick steel plates with different width directions with many types of profiles using one type of caliber roll. be.

Next, an example will be described.

[Example] Fig. 1 is a process diagram of a method according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of a method for determining the reduction amount and shift amount for each pass, and Fig. 3 is a diagram showing a method of determining the amount of reduction and shift of each pass. FIG.

In the figure, 6 is a caliber shape, and the other parts are the same as in FIG. 6, so the explanation will be omitted.

First, the work roll shift (WRS) is used to move the upper and lower working rolls 3 and 4 in the axial direction (perpendicular to the rolled material 5) as shown in Fig. 3.
Using a plate rolling mill with a mechanism, a caliber 6 is attached to the top 3 and bottom 4 of each working roll (WR), and a set of caliber shapes 6 are created by shifting between the rolling passes of the plate rolling machine. With this method, we were able to manufacture a wide variety of thick steel plates with different widths without causing shape defects such as distortion.

Incidentally, the above rolling was carried out according to the process diagram shown in FIG.

First, the input information necessary for rolling: the amount of change in thickness in the width direction (required thickness on the thick and thin sides), the change pitch in the width direction, and other manufacturing specification information (roll shape, etc.) are input into the calculation device. Now, the reduction amount and shift amount (inter-pass change amount) for each pass are determined by considering the following two points.

(1) The thickness profile in the width direction (thickness difference and pitch) required for the product must be obtained at the end of the final pass rolling.

(2) From the start to the end of rolling, determine the amount of reduction, shift, etc. for each pass so that the distribution of elongation in the rolling direction in the rolling width direction is as uniform as possible.

An example of this determination method is shown in FIG.

The shaded area shown in Fig. 2 is the thickness profile in the width direction required at the end of the final pass rolling.In the initial stage of rolling, the vertical relative positions of 3 and lower 4 on the working roll (WR) are shifted so that they are equal. As the rolling progresses, the rolling process is carried out (the state shown by the solid line in the figure, that is, the shifted state in which the upper A position corresponds to the lower B position, and the upper C position corresponds to the lower D position). I gradually changed and lowered the shift for each pass so that the final profile was a diagonal line.

In Fig. 2, a ΔS shift is made between the initial stage and the end of rolling, and if 3 above the working roll is used as a reference, 4 below the working roll is shifted from the solid line to the broken line (the position of lower B is B' , lower D corresponds to D', respectively), and the rolling is completed.

FIG. 4 is an explanatory diagram of another determination method. When the thickness of the rolled material (t ₁ , t ₂ ) as shown in Fig. 4 is required, that is, the difference in thickness is △t=t ₁ −t ₂ When the above △t is required, the shift amount for each pass is , 5th
Rolling is performed in the position shown in the figure, and a thickness difference Δt is obtained in the final pass (n).

According to the above method, it is possible to minimize the uneven distribution of longitudinal elongation in the width direction of the plate for each pass leading to the final thickness profile in the width direction, thereby preventing shape defects from occurring. I was able to get the profile I needed without any hassle.

[Effects of the Invention] According to the method of manufacturing a steel plate having a different thickness in the width direction of the present invention, the following effects are achieved.

(1) With one type of upper and lower caliber shape, many types of steel plates with different thicknesses in the plate width direction can be manufactured.

(2) The rolling shape defects (distortion) observed in conventional rolling with a fixed roll arrangement can be reduced by optimizing the inter-pass shift and rolling reduction settings.

(3) According to the present invention, the steel plate with different thickness in the width direction can reduce the amount of steel plate used by about 10% compared to a conventional flat plate (normal material, that is, a steel plate with uniform thickness in the width direction).

[Brief explanation of the drawing]

FIG. 1 is a process diagram of a method according to an embodiment of the present invention, FIGS. 2 and 4 are explanatory diagrams of a method for determining the reduction amount and shift amount for each pass in the embodiment, and FIG.
An explanatory diagram of a rolling apparatus for carrying out the method of the present invention,
Figure 5 shows the number of passes and shift amount in the example, △t
FIG. 6 is an explanatory diagram of a rolling apparatus in a conventional method. In the figure, 1 and 2: upper and lower backing rolls, 3 and 4: upper and lower working rolls,
5: Rolled material, 6: Caliber shape.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a steel plate with a variable thickness profile in the width direction using a plate rolling mill, comprising: a shift device that allows upper and lower work rolls of the rolling mill to shift in the axial direction; A method for manufacturing a steel plate with different thicknesses in the width direction, characterized in that a work roll having a caliber shape in the axial direction is used, and the work roll is shifted while rolling down between rolling passes.