JPH06126311A - Method for control rolling plate width of thick plate - Google Patents

Abstract

PURPOSE:To control plate thickness with high accuracy when form rolling, cross rolling and finish rolling are carried out to manufacture a thick plate. CONSTITUTION:After a slub is form-rolled, a rolled stock 4 is rotated 90 deg. to a rolling direction and cross-rolled as the plate thickness is controlled. In this cross rolling, the areas on the upper surface of the same rolled stock 4 are measured respectively by a surface shape meter 2 in two different rolling passes, an error of a zero point of a roll gap of a mill 1 is estimated based on these measured values and the cross rolled plate thickness is controlled considering the estimated errors. After cross rolling, further, the rolled stock 4 is rotated 90 deg. to the rolling direction to perform finish rolling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate width control rolling method capable of controlling the plate width with high accuracy when forming a plate by forming rolling, tenter rolling and finish rolling. Regarding

[0002]

2. Description of the Related Art Conventionally, a slab manufactured by continuous casting or slabbing is used as a raw material, and a multi-pass reversible rolling is applied to this slab to manufacture a thick plate having a predetermined size. The rolling of the sheet is carried out by forming rolling, tentering rolling and finishing rolling in multiple passes. The reason for this is that if uneven rolling deformation occurs at the end of the rolled material in this rolling, it will become end crops and side crops of the product, resulting in uncollectible portions and reducing the plate production yield. Therefore, the rolling is performed so that the end crop and the side crop can be minimized and the final shape can be approximated to a square.

That is, the slab heated and conveyed by the heating furnace is reversibly rolled and formed (roughly rolled) to a predetermined thickness so that the slab has a rough shape, for example, a top end and a bottom end in the rolling direction. It has a tongue shape and the side edges are rolled into a staggered shape.

When the forming and rolling is completed, the rolled material is turned by 90 ° with respect to the rolling direction to change the direction, and the widthwise rolling is also carried out by the reversible rolling. In this tenter rolling, the initial shape is not a square shape after the forming pass, and the rolling direction differs from the rolling direction in forming rolling by 90 °, so the shape after tenter rolling is not constant, and the top and bottom edges are not constant. Are fishtails, side edges are rugged (forming rolling: large reduction, tenter rolling: small reduction), or top and bottom edges are tongue-shaped, side edges are jagged (forming rolling: small reduction, tentering) Rolling: Large reduction).

When the tenter rolling is completed, the rolled material is turned again by 90 ° with respect to the rolling direction to change direction, and finish rolling is performed by reversible rolling. By the way, generally, as one of the factors that greatly affects the accuracy of the thickness of rolled material, there is an error in the set value of the zero point of the rolling mill roll gap.

That is, the strip thickness after rolling is determined by the roll interval during rolling, and the roll interval during rolling is the sum of the roll gap S ₀ which is the roll interval when there is no load and the amount of deformation of the rolling machine when there is load. The thickness h after rolling is determined by

[0007]

[Number 1] _{h = S 0 + P / M} ······· However, h: thickness at delivery side (mm) S _0: roll gap (no load at the time of the roll gap, mm) P: rolling load (t) M: Calculated by the mill constant (tf / mm) of the rolling mill. In the first half of rolling, that is, in the stage where the number of rolling is small, the wear of the roll is small, so that the plate thickness after rolling can be accurately controlled by the formula. However, since the amount of roll wear increases as the number of rolling increases, the roll gap increases and an error occurs unlike the initial roll gap S ₀ set at the start of rolling.

The error caused in the roll gap is caused by the plate width control rolling method for a thick plate which is controlled to a target plate width by controlling the plate thickness in the final pass of tenter rolling as described above. This is one of the causes of remarkably lowering the accuracy, and various techniques for reducing this error or a technique for reducing the influence of this error on the plate width precision have been proposed.

[0009] For example, the applicant of the present invention has previously disclosed Japanese Patent Laid-Open No. 62-1371.
According to the publication No. 14, the length of the rolled material (slab width) is measured in the vicinity of the final pass of the tenter rolling, and the plate thickness of the rolled material in the final pass of the tenter rolling is controlled based on the following formula. A method for manufacturing thick plates with plate width was proposed.

[0010]

[Equation 2]

However, H _Dw : Target plate thickness after _tenter rolling W _a : Target plate length after tenter rolling W _D : Plate length measured near the final pass of tenter rolling H _D : Measure W _D It is the plate thickness when it is done.

[0012]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Applicant
The method proposed by Japanese Patent No. 137114 can certainly reduce the influence of the error of the set value of the zero point of the roll gap of the rolling mill on the strip width accuracy more than before. However, in brief, this method is a coping therapy method, and does not actually estimate the error of the set value of the zero point of the roll gap and reflect the error in the strip width control of the next rolled material. Therefore, the plate width control accuracy is still insufficient.

According to this method, when the horizontal cross section of the rolled material 4 becomes a Tyco shape as shown in FIG. 2 (a) or a fish tail shape as shown in FIG. 2 (b) during tenter rolling, measurement is performed. The error in the plate thickness calculation varies depending on the length of the portion, and the plate width control accuracy is reduced.

Although various techniques for improving strip width precision in strip width controlled rolling have been proposed in addition to this method, any of the conventional strip width controlled rolling methods can highly accurately produce strip thickness after tentering and rolling. It has not been possible to control the width of the thick plate with high precision.

Here, an object of the present invention is to perform plate width control rolling of a thick plate capable of controlling the plate width with high accuracy when performing the forming rolling, the tenter rolling and the finishing rolling to manufacture the thick plate. To provide a method.

[0016]

Here, the gist of the present invention is that, after forming and rolling a slab, the rolled material is rotated 90 ° with respect to the rolling direction while controlling the plate thickness. Tensile rolling is performed, and the rolled material is rolled 90 ° in the rolling direction.
In a plate width control rolling method for manufacturing a plate having a target plate width by rotating and finishing rolling, in at least two different rolling passes of tenter rolling,
The area of the upper surface or the lower surface of the same rolled material is measured respectively, the error of the zero point of the roll gap of the rolling mill is estimated based on these measured values, and the plate thickness after tenter rolling is calculated by adding the estimated error. It is a plate width control rolling method for thick plates characterized by controlling.

More specifically, according to the present invention, after the slab is form-rolled, the rolled material is turned by 90 ° with respect to the rolling direction, and the tenter-rolling is performed while controlling the plate thickness, and further rolling. In the plate width control rolling method for manufacturing a plate having a target plate width by rolling the material 90 ° with respect to the rolling direction and performing finish rolling, (i) in different rolling passes during tenter rolling. , Rolling surface of rolled material at least twice
Measuring the area of (upper surface or lower surface of the rolled material) by an appropriate means, (ii) measured surface area, roll gap setting value (gauge meter thickness) S ₀ at the time of measurement, and rolling obtained from these values Determining the set value S ₁ of the roll gap based on the relationship with the volume of the material, and (iii) S ₀
The difference between S ₁ and S ₁ , that is, the error of the roll gap setting value is reflected in the above equation to improve the estimation accuracy of the sheet thickness, thereby controlling the sheet width of the thick sheet with high accuracy. It is a plate width control rolling method for thick plates.

[0018]

The operation of the present invention will be described in detail below. In the present invention, first, in at least two different rolling passes of tenter rolling, the area of the upper surface or the lower surface of the same rolled material is measured, and the error of the zero point of the roll gap of the rolling mill is based on these measured values. To estimate.

FIG. 1 is an explanatory diagram showing an example of the layout of an apparatus used for carrying out the present invention. In the example shown in FIG. 1, the area of the upper surface of the rolled material 4 is measured by the flat shape meter 2, and this measurement data is input to the computer 3. The calculator 3 calculates the error of the zero point of the roll gap of the rolling mill 1 based on the measured values of the same rolled material at least two times in different rolling passes, and outputs the roll gap considering the error to the rolling mill 1. .

According to the present invention, the error of the set value of the zero point of the roll gap of the rolling mill is estimated in this way, and the estimated value is used to control the sheet thickness after tenter rolling with high accuracy to obtain the width. The plate width of the thick plate after strip rolling is controlled with high accuracy.
Furthermore, the present invention will be described more specifically with reference to various arithmetic expressions.

According to the present invention, after forming and rolling the slab, the rolled material is turned by 90 ° with respect to the rolling direction, and tenter rolling is performed while controlling the plate thickness. At the time of finishing rolling by turning 90 ° with respect to, the area A ₁ of the upper surface or the lower surface of the rolled material is measured after at least one pass rolling of tenter rolling.

Assuming that the sheet thickness at the time of measurement is H ₁ , H ₁ is the roll gap of the rolling mill in the rolling pass before the area measurement, that is, the roll gap set value S, rolling load P and mill rigidity coefficient M in the first pass. The difference between the plate thickness H ₁ '(gauge meter thickness) calculated from the rolling mill roll gap zero point Δ
The sum _{(H 1 = H 1 '+} ΔH 1) of H _1. here,

[0023]

[Equation 3]

However, S: roll gap, P: rolling load, M: mill rigidity coefficient.

In the present invention, next, regarding this rolled material,
Further, after performing at least one pass rolling, the area A ₂ of the upper surface or the lower surface of the rolled material is measured. The plate thickness at this time is H ₂
Then, as in the previous case, H ₂ is the sum of the plate thickness H ₂ 'predicted by the equation and the error ΔH ₂ of the roll gap zero point.
(H ₂ = H ₂ '+ ΔH ₂ ) By the way, since the same rolled material has a constant volume before and after rolling,

[0026]

[Equation 4] H ₁ × A ₁ = H ₂ × A ₂ ... Therefore, substituting the above relationships into H ₁ and H ₂ of the equation,

[0027]

## EQU5 ## (H ₁ '+ ΔH ₁ ) × A ₁ = (H ₂ ' + ΔH ₂ ) × A ₂ ... Here, the errors ΔH ₁ and ΔH ₂ of the set value of the zero point of the roll gap of the rolling mill gradually change as the number of rolling increases, as described above.
The same rolled material can be regarded as almost the same, and this error is

[0028]

[Equation 6] ΔH ₁ = ΔH ₂ = ΔH ..... By substituting the equation into the equation,

[0029]

[Equation 7]

Thus, the error ΔH of the set value of the zero point of the roll gap of the rolling mill can be obtained. In the above description of the present invention, the case where the area of the upper surface or the lower surface of the rolled material is measured twice in tenter rolling is taken as an example, but the number of measurements is not limited to two. You may go more than once. In the present invention, when measuring the area of the upper surface or the lower surface of the rolled material by tenter rolling, the error is measured by appropriately combining two arbitrary measurement values and calculating a plurality of errors. Is averaged to calculate an average value, which is desirable because the accuracy can be further improved. Also,
The area may be measured by any suitable means without any limitation.

As described above, since the error of the zero point of the roll gap of the rolling mill can be estimated, it is possible to control the strip thickness after tenter rolling, taking into account the estimated error. , The target plate thickness H _Dw after _tenter rolling is calculated by the following formula instead of using the formula.

[0032]

[Equation 8]

By carrying out the method described above, the strip width after tenter rolling can be controlled with high accuracy regardless of the magnitude of the error in the set value of the zero point of the roll gap of the rolling mill. By the way, the method previously proposed by the present applicant in JP-A-62-137114 is
As described above, since it is a method of measuring the plate length of the rolled material and controlling the plate thickness of the rolled material in the final pass of tenter rolling, a change in the shape of the same rolled material, for example, as shown in FIG. If the rolled material has the shape of a tyco shown in Fig. 2 or the fishtail-shaped front and rear end crops shown in Fig. 2 (b), the error in the plate thickness calculation will fluctuate depending on the length of the measurement portion. On the other hand, according to the present invention, since the plate area is measured instead of the plate length, there is an effect that rolling can be performed while avoiding the influence of the fluctuation of the plate length. Further, the present invention will be described with reference to examples, which are illustrative of the present invention and are not intended to limit the present invention.

[0034]

EXAMPLES In order to quantitatively clarify the effect of the plate width control rolling method for thick plates according to the present invention, after forming and rolling the slabs with the target dimensions shown in Table 1, the rolled material was rolled in the rolling direction. By rolling 90 °, and performing tenter rolling while controlling the plate thickness, and further rolling the rolled material by 90 ° in the rolling direction for finish rolling, and continuously rolling thick plates with the target dimensions shown in Table 1. do it
500 sheets were manufactured.

[0035]

[Table 1]

In this tenter rolling, the area of the upper surface of the same rolled material is measured in two different rolling passes, and the error of the zero point of the roll gap of the rolling mill is estimated based on these measured values. Then, the method of the present invention for controlling the plate thickness after tenter rolling taking into account the estimated error and controlling the plate thickness of the rolled material in the final pass of tenter rolling by measuring the plate length of the rolled material Two methods were used in comparison with the method proposed by Japanese Laid-Open Patent Publication No. 62-137114, and the plate width accuracy of both the method of the present invention and the conventional example was compared. The results are summarized in Table 2.

[0037]

[Table 2]

From Table 2, the cumulative number of rolled sheets is 250 from the first sheet.
Between the first sheet (the first half of rolling), the roll gap due to rolling is small, so the roll gap does not increase much with respect to the initial set value, so the error of the zero point is small, and the conventional example and the present invention example. It can be seen that the difference between the two is small. However, it can be seen that the effect of the present invention becomes clear in the latter half of rolling when the amount of roll wear increases and the roll gap changes significantly from the initial set value.

[0039]

As described in detail above, according to the present invention,
It has become possible to control the plate width with high accuracy when forming a thick plate by performing forming rolling, tenter rolling and finish rolling.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a layout of an apparatus used when implementing the present invention.

FIG. 2 is an explanatory view showing an example of a horizontal cross-section of a rolled material that occurs during tentering rolling. FIG. 2 (a) shows a case of a Tyco shape, and FIG. 2 (b) shows a fishtail shape. It is explanatory drawing which shows each case.

[Explanation of symbols]

 1: Rolling mill 2: Plan shape meter 3: Calculator 4: Rolled material

Claims (1)

[Claims] 1. After forming and rolling the slab, the rolled material is turned by 90 ° with respect to the rolling direction, and tenter rolling is performed while controlling the plate thickness. Further, the rolled material is rolled with respect to the rolling direction by 90 °.
In a plate width control rolling method for manufacturing a plate having a target plate width by rolling and finishing rolling, a top surface of the same rolled material in at least two different rolling passes of the tenter rolling. Alternatively, each area of the lower surface is measured, the error of the zero point of the roll gap of the rolling mill is estimated based on these measured values, and the strip thickness after tenter rolling is controlled by adding the estimated error. A method for controlling plate width control of thick plates.