JPS62230404A - Rolling method for thick plate - Google Patents

Abstract

PURPOSE:To decrease the generation rate of products having defective widths and to reduce the reduction ratio at the end faces in the transverse direction after finish rolling. CONSTITUTION:The rolling material 1 is moved toward a horizontal rolling mill 3 and is longitudinally rolled prescribed times by the rolling mill 3 until the prescribed thickness is attained. The rolling material 1 is passed through the position of a thickness measuring instrument 5 and the width distribution in the thickness direction is measured at the point A. The thickness is measured as well as at the point B before the final pass. The rolling material 1 is turned 90 deg. just before the point B in order to point the transverse end faces of the rolling material 1 toward the measuring heads 5a, 5b of the measuring instrument 5. The rolling material is again turned 90 deg. after the end of the measurement and is subjected to cross rolling of the final pass. The correction of the roll rolling reduction position of the horizontal rolling mill 3 at the point C is calculated by the width measured at the point A and point B. The width control with high accuracy is realized by the above-mentioned method even in the rolling stage having no edgers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for rolling a thick plate, and more specifically to a method for rolling a thick plate including a tentering rolling step.

[Prior art]

In plate rolling, in order to obtain a thick plate with a predetermined width,
Normally, tenter rolling is performed, and the rolling process involves first rolling the rolled material to an appropriate thickness, then turning the rolled material 90', performing tentering rolling to widen the width of the material, and then rolling again. The rolled material is turned 90 degrees and finish rolled until it reaches a predetermined thickness.

The width dimension of the thick plate manufactured by such a rolling process is
In order to obtain a thick plate with a predetermined width that is not constant in the length direction, it is necessary to process the end face in the width direction to remove unnecessary parts after finishing rolling, which causes a decrease in yield. was.

Therefore, there is a strong desire for a rolling method that accurately controls the strip width after finishing rolling, and various inventions have been made in the past.The main contents of these inventions will be outlined below.

(11 Method using plate width gauge (Japanese Patent Application Laid-Open No. 56-136210
No.) A strip width gauge is installed near the rolling mill, and the strip width of the rolled material immediately before tentering rolling is measured by the strip width gauge, the strip thickness at that time, and the target strip width after tentering rolling. , Calculates the plate thickness at the final bus of tentering rolling, and performs tentering rolling to achieve this thickness.

(2) Method using Esoger (Japanese Unexamined Patent Publication No. 59-10
No. 7713, No. 59-220209) The end face in the width direction of the rolled material that has been subjected to tenter rolling is width-rolled using an Esoger to adjust the final sheet width.

(3) Method focusing on temperature drop during tentering rolling (JP-A-59-7413) Strip width, strip thickness, and temperature at the start of tentering rolling, and target strip width and expected temperature after finishing tentering rolling The thickness of the plate at the end of tenter rolling is calculated based on this, and the plate is rolled to achieve this thickness.

[Problem that the invention seeks to solve]

By the way, due to various factors such as dimensions, temperature, reduction amount, roll dimensions, etc., both end faces of the rolled material in the advancing direction have a concave shape at the center in the thickness direction and a convex shape at both ends in the thickness direction. (see FIGS. 2 and 4), and this deformation is superimposed and increases with each rolling bath.

Due to this deformation during tentering rolling, both end faces in the width direction of the rolled material before finish rolling are significantly deformed.
After tentering rolling to a thickness of 140 mm and a width of 2400 days, the widthwise dimensional difference between the convex portion and the concave portion on both end faces in the width direction reaches as much as 151 mm.

However, in the methods shown in (1) and (3) above,
Since the rolling schedule is determined without taking this deformation into account at all, if this deformed portion is removed after finish rolling to a predetermined strip width, there is a risk that the jIFi width will be insufficient.

In addition, method (2) above is an effective method, but
This method cannot be used in rolling processes that do not have an edger installed, and the problem is that installing a new edger requires a considerable amount of investment and installation space.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a thick plate rolling method that can realize highly accurate plate width control even in a rolling process without an edger.

[Means for solving problems]

The thick plate rolling method according to the present invention corrects the target plate thickness in subsequent steps based on the deformation state of both end faces in the width direction of the rolled material, and includes tentering rolling to roll the rolled material to a predetermined width. In the thick plate rolling method including the process, the plate width distribution in the plate thickness direction of the rolled material is measured before the final bus of tentering rolling, and based on the measurement result, at least at the final bus at the measurement time J2/down. It is characterized by correcting the target plate thickness.

〔Example〕

Hereinafter, the present invention will be explained based on drawings showing embodiments thereof. FIG. 1 is an explanatory diagram of a rolling process for carrying out the method for rolling a thick plate according to the present invention (hereinafter referred to as the method of the present invention).

In the figure, 1 is a rolled material, and the rolled material 1 moves on a rolling line 2 as indicated by the arrow in the lower half of FIG. The plate is rolled until it becomes a thick plate having a predetermined thickness and width.

Measurement rads 5a and 5b of the strip width measuring device 5 are installed at positions spaced apart from the horizontal rolling mill 3 by a suitable length in the longitudinal direction of the rolling line 2, and are spaced apart from each other by a suitable length at right angles to the longitudinal direction of the rolling line 2. Both of these are located at the same height as the rolled material 1 moving on the rolling line 2. As the plate width measuring device 5, one capable of measuring the plate width distribution in the thickness direction of the rolled material 1 is used, for example, the plate width measuring device disclosed in Japanese Patent Application No. 60-285051. FIG. 2 is a schematic diagram showing the configuration of the plate width measuring device 5. As shown in FIG.

The measuring heads 5a+sb for the plate width measurement W5 have the same configuration, and the configuration of one measuring head 5a will be explained below, and the explanation of the other measuring head 5b will be omitted.

The measurement head 5a emits laser oscillation r:t51. It is composed of a half mirror 52, a galvano mirror 53, a parabolic mirror 54, a distance measuring section 55, and the like.

The laser oscillator 51 emits a laser beam whose intensity varies periodically, and the laser beam is transmitted through a fixed half mirror.
At 52, the light is separated into two directions: a distance measuring section 55 and a galvanometer mirror 53.

The galvano mirror 53 is reciprocally reversed by a predetermined angle at a constant period, and the laser beam whose reflection direction has been changed by the galvano mirror 53 is reflected by the parabolic mirror 54, and the laser light is The end surface 1a is irradiated horizontally, and the end surface 1a is irradiated horizontally.
It is scanned at a constant speed in the thickness direction of a.

The laser beam reflected by the end face 1a is again reflected by the parabolic mirror 54 and the galvanometer mirror 53, and is applied to the distance measuring section 55 via the half mirror 52. The distance measuring section 55 captures the laser beam provided from the laser oscillator 51 via the half mirror 52 and the laser beam reflected on the end surface 1a of the rolled material 1 as electrical signals.
Due to the phase difference between the two, a reference point 56 is set at a position at an appropriate temperature away from the measuring head 5a toward the rolling line 2 in a direction perpendicular to the longitudinal direction of the rolling line 2, and a measuring point 57 on the end surface 1a of the rolled material 1 is determined. Find the horizontal distance Il between. Similarly, the measuring head 5b, which is disposed opposite to the measuring head 5a across the rolled material 1 and scans the laser beam in synchronization with the measuring head 5a, moves the measuring head 5b to the rolling line 2.
Another reference point 56' is set at a position separated by an appropriate temperature on the side, and a measurement point 57 on the end surface 1a' of the rolled material l opposite to the end surface 1a.
'Horizontal hole f'! l j! 2 is required. Therefore, the plate width W in the horizontal plane including the measurement points 57 and 57' of the rolled material 1 is the same as the above-mentioned 1. , the value of It2, and the reference point 56,
The horizontal distance W' between the reference points 56' is given by the following equation.

W=W'-(77,+12)...
(1) Now, rolling according to the method of the present invention is carried out in the following procedure. First, the rolled material l is horizontally rolled from the right side in Figure 1! 3, and is rolled a predetermined number of times in the longitudinal direction by the horizontal rolling mill 3 until it reaches a preset thickness. This step is the pre-tenting rolling step.

After completion of the tentering pre-process, the rolled material 1 passes through the sheet width measuring device 5 at the point indicated by A in FIG. 1, and the sheet width distribution in the sheet thickness direction is measured.

Next, the rolled material 1 moves toward the horizontal rolling mill 3 again, is rotated by 90 degrees in the horizontal plane on the way, and is rolled a predetermined number of times in the width direction by the horizontal rolling mill 3. This process is the tentering rolling process. In the method of the present invention, the plate thickness is also measured by the plate width measuring device 5 at the time point indicated by B in FIG. 1 before the final bath of the tentering rolling process. In this case, in order to make the end faces of the rolled material 1 in the width direction face the measuring heads 5a and 5b of the measuring device 5, the rolled material 1 is rotated 90 degrees just before time B, and then rotated 90 degrees again after the measurement is completed. After being rotated, the final bus is rolled in a horizontal rolling mill 3 for width adjustment. The roll rolling position of the horizontal rolling mill 3 in this final bus, indicated by C in FIG. 1, is calculated as described below from the strip width measured at the points A and B.

The rolled material 1 after completion of tentering rolling is once again rotated by 90 degrees, and then rolled in the longitudinal direction a predetermined number of times in the horizontal rolling mill 3 until the final target thickness is achieved.

This process is the finish rolling process.

Now, a method for calculating the roll rolling position of the horizontal rolling mill 3 in the final bus of the tentering rolling process from the measured values of the strip width measuring device 5 operating at the points A and B will be described below.

In measuring the sheet width at points A and B, the laser beam irradiated from the measuring heads 5a and 5b is scanned vertically up and down, but since the rolled material l is moving horizontally, the end face The scanning locus of the laser beam on 1a or la' has a sawtooth shape as shown in FIG.

Nam nn -tr 1h +, "4->1.%"
7”ke tenzu frE 'J risQ J,, -x,
~* While the laser beam scans the respective ranges indicated by -, the effective plate width We and the invalid section of the rolled material 1 are determined by the values of Il and I12 respectively output from the plate width measuring device 5. The areas ΔSw and ΔSd are calculated in each range of al''-an.

FIG. 4 is a cross-sectional view of the rolled material I in the width direction.

The shape of both ends of the cross section of the rolled material 1 in the width direction is deformed by rolling as described above. The ineffective section cross-sectional area ΔSdi, Δ5ini in the range a1 is the area of the crosshatch section in FIG. 4, and the effective plate width W e i is ΔSdi
and the board width excluding ΔSwi.

Now, the maximum values of the detection values 'li+'2i of the plate width measuring device 5 detected in I area ai are calculated as 'li'+'2i
', the effective plate width W e i in the range ai is
It is calculated by the following formula based on the above formula (11).

Wei=W'-(1,l'+I12.')-
・(21 Also, ΔSdi and ΔSwi at that time are the difference between the detection values l1li, ``2i'' of the plate width measuring device 5 in the range ai and the respective maximum values 'li' + '21' of the plate of the rolled material 1. Calculate by integrating in the J\ direction.

W e i , ΔSdi and ΔSwi are the above a, ~
3n, and their average values We, S
d and ΔS- are used in the following calculations.

We=ΣWei10 (i:1,2.-...1
) −(31ΔSd =ΣΔSdi/n (i −1
,2,-n) -+4)ΔSw=ΣΔSei/n
(i = 1.21...n) - (51 The target plate thickness Hdw at the final bus for tentering rolling, that is, the 0 point in Fig. 1, is given by equation (3), equation (4), and equation (5) The calculated W
It is calculated by the following formula using e, ΔSd, ΔS-, etc.

Hdw= (We −α)・I+ 2 /Wdw
−f61Wdw= (Wp +β)−ΔWdf
...(7) However, Wdw: Target sheet width after tentering rolling H2: Gauge meter sheet thickness at point B Wp: Required product width ΔWdf: Predicted value of width expansion amount during finish rolling, known width expansion A value calculated by a formula.

α in equation (6) is a correction value for the decrease in effective strip width We due to an increase in the amount of deformation of the cross section in the strip width direction in the final bus of tentering rolling, and Δ is calculated as a result of strip width measurement at point A.
The prediction is made using the invalid board widths ΔWea and ΔWeb, which are respectively calculated from the following equations from Sda, ΔSwa and ΔSdb, ΔSwb calculated as a result of the board width measurement at point B.

ΔWea=(ΔSda+ΔS wa)/H2−(8
)ΔWeb=(ΔSdb+ΔS 1yb)/Hl−
(9 H2: Gauge meter plate thickness H at point B
, : Gauge meter plate thickness at point A Formula (8) 8 Using the calculation result of Formula (9), the correction value α is calculated by the following formula.

α=(ΔWea−ΔWeb)/va
-00 mawashi m: Number of tentering rolling buses from point A to point B. Also, β in equation (7) is the allowance for the width increase amount in consideration of control accuracy and camber amount in the final tentering rolling bus. be.

Now, the rolling schedule up to the final bus in the tentering rolling process is set in advance based on the rolling target width Wr, which is the required product width wp plus a predetermined margin ΔWr, and the rolling schedule of the horizontal rolling mill 3 in the final bus is set in advance. The pressure position is this Δ
The following settings are made depending on the magnitude relationship between the value of Wr and the value of (AWea+α+β).

i) If ΔWr≧(ΔWea+α+β), use formula (6
In order to realize the target plate thickness Hd- calculated in ), the rolling position of the rolling mill in the final bus is calculated, taking into consideration the deformation of the rolls, etc.

ii) When ∆W〈(∆Wea+α+β), the parameter

a) When x≦K・(ΔWhw+ΔWe Tsuba), Δw
h- is the value obtained by converting the plate thickness tolerance into plate width, that is, the amount of increase in plate width when the length is kept constant and the plate thickness is reduced to the minimum value within the plate thickness tolerance range, and ΔWew is the value of the plate width of the finished product. The value obtained by converting the board length allowance into the board width, that is, the amount of increase in board width when the board thickness is constant and the pre-estimated allowance in the board length direction is set to 0.K is a constant between 0 and l. be.

In this case, after performing the final bus of tentering rolling with Hdw calculated by formula (6) as the target thickness, the target thickness Hdf in the final bus of subsequent finishing rolling is calculated by the following formula. Decrease by ΔHx.

ΔHx='AK·ΔHt−(11) However, ΔHt is the plate thickness tolerance and is calculated by the following formula.

Hdf-ΔHt wp b) When x>K (ΔWhw+ΔWew) In order to secure the required product width Wp, the plate thickness must be made thinner than the tolerance range, or the plate length is insufficient.
Subsequent rolling will be stopped and an alarm such as a buzzer or bell will be sounded to notify the operator.

〔effect〕

As described in detail above (in the method of the present invention, the strip width distribution in the thickness direction of the cross section of the rolled material in the width direction is measured during the tentering rolling step, and based on the measurement results, the
Since the effective width of the finished product is calculated and the effective width is used to determine the roll rolling position in subsequent tentering rolling, the deformed portion of the end face in the width direction, which was about 0.15% in the conventional method, is reduced. The occurrence rate of products with insufficient board width after removal is 0.0
5%, and furthermore, it is possible to reduce the amount of processing on the width direction end face after finish rolling, and it has excellent effects such as improving the yield.

In this example, the strip width distribution was measured immediately before the final bus of the tentering rolling process, but this measurement may be performed at any time before the final bus of the tentering rolling process, and the results are Based on this, the roll rolling position in each bus in the subsequent tentering rolling process may be determined. However, the earlier the measurement is performed, the more inaccurate the correction value αΦ value calculated at 200 becomes.

Furthermore, by accumulating the measured values of the strip width distribution during tentering rolling in the method of the present invention for each rolling condition and organizing the changes in shape of the width direction end face, it is possible to calculate the margin for the strip width that should be provided when designing the slab. can be minimized.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram of the rolling process for carrying out the method of the present invention, FIG. 2 is a schematic diagram of a sheet width measuring device, and FIG. FIG. 4 is a cross-sectional view of the rolled material in the sheet width direction. 1... Rolled material 3... Horizontal rolling mill 5... Strip width measuring device A, B... Strip width measuring point patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono 3 Day

Claims (1)

[Claims] 1. A thick plate rolling method including a tentering rolling step of rolling a rolled material to a predetermined plate width, wherein the plate width distribution in the thickness direction of the rolled material is determined before the final bus of tentering rolling. A method for rolling a thick plate, characterized in that the target thickness of the plate at least in the final bath after the time of measurement is corrected based on the measurement result.