JPS6356304A - Production of less trim steel sheet - Google Patents

Abstract

PURPOSE:To execute edging for the purpose of correcting the shape of an end face and to improve overall costs and working accuracy by specifying the edging amt. at the time of finish rolling, the shape correction amt. at the time of shape adjustment rolling and the shape correction amt. at the time of cross rolling, respectively, to specific values. CONSTITUTION:The rollings to edge the longitudinal end of a stock to be rolled in the finish rolling at least at 70mm in total, to correct the shape in the shape adjustment rolling just prior to the cross rolling at >=8mm and to correct the shape in the cross rolling just prior to the finish rolling at <=6mm are executed by finishing mills 1, 2. At least >=1 times of the edgings are further executed when (1.4-0.2beta) is attained where the shape ratio is alpha and the cross rolling ratio is beta. The costs and quality are improved by the above-mentioned method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a cut plate or a steel plate with ears, and in particular, it prevents seam flaws that occur near the longitudinal ridgeline of the steel plate and improves the side end surface of the steel plate. To provide a method for manufacturing rest trim steel plates and grooved steel plates economically and at high yields by roll-engineering and cutting.

[Conventional technology]

Generally, in the production of steel plates, shape adjustment (DBT) rolling,
Etching rolling is a method for controlling the width of a steel plate in either widthwise (DW) rolling or finishing (DB') rolling, and in continuous hot rolling, Japanese Patent Publication No. 50-24907
Publication No. 51-36711, Special Publication No. 52-
No. 1700, etc., and for thick plate rolling, Japanese Patent Application Laid-Open No. 56
-80310 publication, Japanese Patent Application Laid-open No. 56-53808,
JP-A-58-122106, JP-A-58-173
Publication No. 004 and the like have been proposed.

On the other hand, as a method for fully controlling the planar shape of a thick plate, especially the rectangularity, it is possible to improve the rectangularity of a steel plate in either or both of DW rolling or shape adjustment rolling for the purpose of eliminating thickness deviation before DW rolling. JP-A-52-57061 and JP-A-5
No. 3-123358, Japanese Unexamined Patent Publication No. 55-45517, etc. have been proposed.

Furthermore, in recent years, I) AT rolling and C
A method of controlling the planar shape of a steel plate by combining one or both of DAT rolling and L-direction etching in the directional etching and DW rolling passes is also disclosed in JP-A-59-2152.
This method has been proposed in Publication No. 03, etc. ! f. Techniques for reducing the canopy of steel plates include techniques for correcting the reaction force difference during rolling or techniques for controlling the amount of wedging of steel plates, etc. -75812
Publication No. 155961/1983, Japanese Patent Application Laid-Open No. 1982-155961
This method has been proposed in Japanese Patent Publication No. 109509 and Japanese Patent Publication No. 60-3882.

On the other hand, in the production of thick plates, in the case of relatively thin steel plates, shearing (rotary trimming shear, side shear, double side shear), shearing, thick steel plates that are not processed by shearing lines, and In the case of special steels such as high carbon steel or low alloy steel, gas cutting (portable gas cutting, flame flarer cutting, powder gas cutting,
All of these are detailed in ``Recent Advances in Plate Manufacturing Technology in Japan,'' second edition, published by the Japan Iron and Steel Institute, May 23, 1980.

Gas cutting is generally used as a width cutting method or a bevel cutting method as a secondary processing of steel plates. When manufacturing UOE steel pipes from cut thick plates, side trimmers and thin ice knots were used in the early days, but today planers that arrange knots are the mainstream bevelling device. 1. When manufacturing spiral steel pipes from as-rolled hot coils, a rotary shear is used as a side trimmer device, and a bite or milling method is used as a beveling device. In some cases, the milling method also serves as a side trimmer device and beveling device for meat pipes. These are all “Steel Handbook No.
2) Detailed information is provided in "Bunshu, Maruzen, Published November 20, 1980."

Furthermore, the present inventors have proposed a method for creating a hot-rolled steel sheet that improves the hot-rolling yield and the end surface quality of the hot-rolled steel sheet by cutting the edges of the rolled steel sheet after controlling the rectangularity of the rolled steel sheet. Patent application No. 40540/1982 and Patent application No. 7/1983 were filed earlier.
No. 6670 and Japanese Patent Application No. 60-113753.

In addition to these, vertical cracks that occur on the front and back surfaces of steel plates near one longitudinal ridgeline in the manufacture of thick plates are called seam flaws or side cracks due to their shape or location, and there are ways to prevent their occurrence. Various proposals have been made.

In order to ensure the prevention of this kind of flaws in high-grade steel, corners are cut at the longitudinal ends of the ingot, as proposed in, for example, Japanese Patent Publication No. 16928/1983. On the other hand, in mass-produced steel,
As proposed in Japanese Patent No. 19908, it is attempted to completely prevent the occurrence of defects by adjusting the shape of the slab or by performing light reduction rolling at the initial stage of tentering rolling. Furthermore, special public service 1977-14
In the proposal made in Japanese Patent No. 632, the center of both end faces of the slab is indented by convex carrier rolls to provide a training effect and to prevent the occurrence of flaws.

Furthermore, Japanese Patent Publication No. 59-39202 proposes a method of rounding the corners of a thick plate slab with a radius of curvature between 20 and 80 degrees.

In Japanese Patent Application No. 61-67552, the present inventors also proposed a new method for preventing the occurrence of seam defects by performing edging, chamfer rolling, and lubrication rolling during finish rolling.

[Problem that the invention seeks to solve]

Although the planar shape of the thick plate has been improved to some extent by the above technology, due to the occurrence of width return, width widening, edge drop, etc. in the horizontal pass after the engine pass in finish rolling, no rim cutting is required. It was impossible to manufacture steel plates.

On the other hand, unlike hot coil cutting, edge cutting of thick plates requires a short rolling length and no tension control during rolling. For example, gas cutting is the cheapest method with low productivity and very poor cutting accuracy, or shearing is the cheapest method but increases equipment costs but is highly productive, to achieve a given width dimension and edge. Although the shape was obtained, the use of these methods resulted in a substantial overall loss.

The above-mentioned gas cutting or shearing is also used to manufacture thick plates with small width variations by shape correction rolling or edging rolling, etc., and due to the poor cutting accuracy, the rectangularity of the planar shape, especially the width accuracy ( There is a drawback that the improved effects of 5DAT rolling etc. cannot be utilized at all, and even if DATEE rolling etc. were carried out under this cutting precision, the substantial yield improvement was minute.

However, although the above proposal by the present inventors has achieved a macroscopic reduction in the amount of cutting at the side edges of thick steel plates, there is no problem with conventional manufacturing methods for thick steel plates, especially gas cutting or shearing, and 'frcEE The local width drop at the trailing end (the width drop shown in Note (2) of Table 5, not the width drop at the cutting edge) prevents further significant reduction of the cutting amount of the entire thick steel plate. However, the microscopic fact that there is was overlooked, and the disadvantage that the edge quality of edged materials cannot necessarily be improved to the same level as that of cut edge materials was left unsolved.

On the other hand, if shape-correcting rolling or edge rolling is not performed, cutting with a steel plate edge mirror or the like on a thick plate with large width fluctuations will result in significant economic efficiency due to shorter tool life, cutting efficiency, and larger cutting equipment. There was a real drawback that it was damaged. Therefore, when beveling a steel plate, it is limited to secondary processing in a separate process after cutting, rather than in the thick plate manufacturing process, from the perspective of hanging, PJ, and economics. It had serious shortcomings that made it impossible to bear the losses.

Furthermore, among the aforementioned techniques for preventing seam flaws, although corner cutting is extremely reliable in preventing seam flaws, its adoption is not suitable for mass-produced steel in terms of workability and yield loss, and it The disadvantage was that it was limited to.

In addition, light reduction rolling had the disadvantage that it hindered rolling productivity and lacked certainty of its effect1.On the other hand,
Rolling that uses a convex carry/mole roll to make a depression in the center of both sides of the slab can be expected to have an indirect effect because it absorbs the width expansion of the steel plate and does not have an indirect effect on the location of seam flaws. However, it has the disadvantage that it is not very effective in eliminating seam flaws.

[Means for solving problems]

The present invention arranges at least one pair of horizontal rolls and one pair of vertical rolls to perform shape adjusting rolling and widening rolling of a material to be rolled, and if necessary, shape correcting rolling and finishing rolling of one or both of the above rolling steps. When the rolled material is subjected to end face cutting to produce the entire thick steel plate, the longitudinal ends of the material to be rolled are subjected to a total of at least 70 strokes in finish rolling, and shape adjustment rolling immediately before width rolling. The amount of shape correction in the finishing rolling step 1 is set to 8 mm or more, the amount of shape correction in the widening rolling immediately before the finish rolling is set to be less than k 6 w, and the shape ratio α is When the width ratio is the total β (14-
0,2β], the inflection point is corrected by at least one pass of rolling before and/or after the horizontal pass in which the rolled material widens and takes on an end face shape with an inflection point. A method for producing a rest rim steel plate, characterized in that at least one pair of horizontal rolls and one pair of vertical rolls are arranged in an arrangement I- to adjust the shape of the material to be rolled, to widen the rolled material, and if necessary, to perform one or both of the above rolling steps. When producing a thick steel plate by performing all shape correction rolling and finish rolling, and then cutting the end face of the rolled material, the ends of the rolled material in the length direction in the finish rolling must be etched for a total of at least 70 minutes, and width cutting is performed. The shape correction amount in the shape adjustment rolling immediately before rolling is set to f 8 mx or more, and the shape correction amount in the widening rolling immediately before finish rolling is set to 6 mm or less. In addition, in the finish rolling, the shape ratio α When the width ratio is β, (1,4-0,2β), before and/or after the horizontal pass where the rolled material has an end face shape with an inflection point due to width expansion, Is it possible to completely eliminate the above-mentioned inflection points by chamfering the corners of the rolled material for at least one pass? : A method for manufacturing a rest rim steel plate, which is characterized by arranging at least one pair of horizontal rolls and one pair of vertical rolls to adjust the shape of the material to be rolled, width rolling, and optionally one or more of the above-mentioned rolling methods. When performing both shape correction rolling and finish rolling, and then cutting the end face of the rolled material to fully manufacture a thick steel plate, the total length of the lengthwise ends of the rolled material in finish rolling is at least 70 mm.
The shape correction amount in the shape adjustment rolling immediately before the width rolling is 8U or more, and the shape correction fte6+u in the shape adjustment rolling immediately before the finish rolling.
In addition to performing all combinations of the following, in finish rolling, when the shape ratio α is the width ratio β (1, 4
-0,2β), lubrication is applied between the horizontal roll and the rolled material in the horizontal nox where the rolled material has an end face shape with an inflection point due to width expansion, or in this horizontal pass and the previous horizontal pass. This is a method for manufacturing a rest trim steel sheet, characterized in that the formation of the inflection point is prevented by rolling.

[Effect]

First, in order to make the planar shape improvement technology of steel plates more rational from the perspective of the entire manufacturing process, the present invention aims to improve the online rolling width accuracy, that is, to minimize the amount of edge cutting, and to improve the flat shape of steel plates. It is possible to manufacture grooved steel plates by improving the finishing accuracy until the final product is obtained, and then it prevents the occurrence of seam flaws that prevent this from happening, thereby realizing rest trimming of thick plates or high value-added steel plates online in the plate manufacturing process. This is what I did.

Hereinafter, the effects of the present invention will be explained in detail starting from an example of improving width finishing accuracy in thick plate rolling.

In plate rolling, which is characterized by seven-strip rolling and tentering rolling, when rolling thick steel plates, the width deviation between the plates is 20 to 40.
It was found that there is a deviation of about 10 to 30 degrees, and the wider the range of modification, the larger the deviation becomes.

When etching rolling is applied to this, the width deviation between plates is significantly improved to about 5 to 10 mm, and the plate thickness deviation is also improved to about 6 to 12 mm.

Suitable size for edging rolling and DAT rolling 10~
If a slight shape modification of 20 mm is applied, the deviation of the width of the board will be slightly improved to about 5~10m, and furthermore, if the can-no-no-control sub-technique is applied in combination, the width including the can/no-o will be improved. It was found that the plate thickness deviation was significantly improved and became about 2 to 5η.

On the other hand, the cutting method for thick plates is limited to shearing or gas cutting as mentioned above, and the shearing accuracy is t~1.5t (t
: plate thickness], gas cutting accuracy is 5 to 10 mm, but the cutting cost is slightly higher in the latter than the former, and the productivity is also significantly lower.

However, when Edge Miller, which is common as a machine tool but has not been put into practical use as a thick plate manufacturing device, is installed in the full thickness plate manufacturing process to cut a thick steel plate, the cutting accuracy depends on the plate thickness, Although it is influenced by cutting speed and end face shape,
It has been found that the combined method of roll etching and end face cutting of the present invention dramatically improves cutting accuracy to about 1 ms.

From this, in order to obtain a width deviation of a thick steel plate that corresponds to the width cutting accuracy in the end face cutting method of the present invention, it is necessary to minimize the amount of width drop due to unsteady deformation at the rear end of the rolling tip. I learned all about it. In addition, in order to improve the plate gap and plate width deviation, and further minimize the width drop M- and 'c, it was found from Fig. 1 that it was necessary to limit the total amount of L-direction edging in DIF' rolling to 70+llJ or more. Ta. It has also been learned that if the amount of edging exceeds L50ma, the amount of crop increases, so it is preferable that the amount of edging is 150m or less. Also, from the results shown in Fig. 2, DATf! of DAT rolling in DBT rolling immediately before DYEE rolling! ', it was confirmed that it was necessary to limit the width to 8 mm or more based on the amount of width change of the unsteady part. Furthermore, when DAT in DBT rolling and L direction etching are combined, DA in DW rolling immediately before DF rolling
As the T amount decreases, the cropping amount decreases, and as shown in FIG. 3, the necessity of limiting the T amount to 6 or less was confirmed.

The rolled material manufactured based on these findings can also be grooved online, establishing the basis for manufacturing grooved steel plates.

Further, based on this knowledge, when manufacturing grooved steel plates in the thick plate process, the edge processing of thick steel plates is carried out by simply controlling the cutting angle of the edge mirror used for edge cutting in the case of T and V grooves. In addition, we have discovered that in the case of complex shapes such as Y-grooves, this can be achieved most efficiently by arranging a plurality of edge mirrors in succession.

Based on these findings, the above-mentioned high-precision and multi-purpose cutting device is combined with a rolling device that controls the width accuracy of the steel plate, and the edge mirror is applied as a secondary processing after edging rolling is performed as a primary processing by the rolling device. It is not just a matter of realizing industrially viable rest trimming for the first time and achieving a significant improvement in yield, but also by reducing the cutting allowance, cutting efficiency (T/H) is improved, and the blade unit consumption is significantly reduced. It has been confirmed that various cost benefits can be obtained, such as improved efficiency, downsizing of the cutting equipment, and a drastic reduction in equipment costs. As a result, it has become possible to manufacture rest trim steel sheets including grooved copper sheets online, and we have established a technology that allows us to supply thick plate products with high added value to customers in a short production period, with high precision, and at low cost. It has come to this.

Next, the action of eliminating seam flaws will be explained in detail.

As shown in Figures 7(a), (b), and (c), seam flaws occur during horizontal finish rolling in thick plate rolling (when the horizontal rolling of the material to be rolled progresses, the width of the cross-sectional side edge increases). When the area is wide, the material to be rolled is fixed by the horizontal rolls and the end face shape has an inflection point Pi (stage A).As the horizontal rolling progresses further and the width becomes larger, the inflection just below the ridgeline of the material to be rolled occurs. The side of point P goes around to the front and back sides (B stage)
, due to the widening due to the subsequent horizontal reduction,
A seam flaw K occurs in the form that the inflection point is caught (
C stage.

Due to such plastic flow of the material, seam flaws occur at a location 1 minute from the widthwise end (side end) of the front and back surfaces of the rolled material.
The present inventors have found that it moves to the center side of the front and back, which is between 0 and 50.

Furthermore, when tentering rolling is performed, seam flaws often move into the interior of the steel sheet and reach up to 50 to 100 U from the edge of the steel sheet. By horizontal rolling, the end face of the rolled material changes from a macroscopic double bulge shape to a drum shape (single bulge) depending on the width. In the case of tentering rolling, the end face shape of the material to be rolled is such that horizontal finish rolling starts from a state closer to a drum shape than a drum shape, as a result of the rolling by the horizontal rolls during tentering rolling penetrating to the center of the thickness, as described above. It has been discovered that the change in the micro end face shape of the rolled material, that is, the occurrence of the inflection point P, is accelerated.

The occurrence of the inflection point P in the material to be rolled is related to the tentering ratio and rolling conditions. Specifically, if the rolling shape ratio α is α≧(1,4-0-2β) (β-tenting ratio ) was found to be the time of the horizontal reduction pass.

Here, the rolled shape ratio α is defined by the following equation.

J/2 (H1+H2) However, R: Horizontal roll radius Hl: Inlet side plate thickness q during horizontal reduction H2: Output side plate thickness during horizontal reduction △H: Reduction amount during horizontal reduction (ΔH = H1 - H7) Based on this knowledge, we conducted repeated experiments on edge edge rolling, corner chamfer rolling, and lubrication rolling to eliminate the occurrence of seam defects, and as a result, we were able to prevent the occurrence of inflection points on the side edges of the rolled material. Edging rolling is effective in repairing inflection points in the end face shape, corner chamfer rolling is effective in eliminating inflection points in the end face shape, and lubrication rolling is effective in repairing inflection points in the end face shape, and lubrication rolling is effective in repairing inflection points in the end face shape. It was confirmed that the method is effective in preventing the occurrence of inflection points, and that any application is an effective means for preventing seam flaws.

〔Example〕

One embodiment of the invention is fully described below. Table 1 shows an example of manufacturing a rest trim steel plate, and Table 2 shows an example of manufacturing a grooved steel plate.

The slab size in this example is thickness 240mm x width 1800yjl x length 5000mar - finished product size is thickness 24mm x width (1800 or 3600 or λO 5400yya) There are 3 levels for each, and the starting thickness is 2.
Aligned to 00ma.

As is clear from the difference in the amount of width drop shown in Figures 1 and 2 and Table 1, the example of the present invention can produce a product with a cutting amount of 60% or less compared to the comparative example, making it possible to downsize the cutting device and reduce the cutting speed. The grip has greatly improved.

Incidentally, the camper control may utilize conventionally known technology, but the camper control in this example feeds forward the measured value of the can amount by the can/mo meter to independently control the horizontal roll gap amount on the left and right sides. I did it under control.

As for seam flaws, as is clear from Tables 1 and 2, seam flaws were prevented from occurring in the examples of the present invention compared to the comparative examples, and the repair rate and rejection rate were significantly reduced, which greatly contributed to the improvement in yield2. As shown in Fig. 8, the equipment used in this example includes an etching and chamfering roll, a reversible horizontal roll 2, a leveler 3, a cooling bed 4, an ultrasonic flaw detection device 55, a dividing shear 6, a plurality of edge mirror groups 7, and a filler. 8. Measuring device group such as width meter, can/maw meter, gamma ray thickness meter, etc. 9. Width meter 10. Control output devices II and 11 control the roll opening degree, reduction amount, and processing speed of each of the etching and chamfering roll (■) and the reversible horizontal roll 2 using a measuring device group 9, and output all processing results.
The cutting operation receives the output from the width meter IO and inputs the signal from the width gauge IO to continuously calculate the cutting 'M- over the entire area of the edge of the steel plate (ilIl), and instructs the control device EM of the edge mirror 7 to cut the amount and cutting speed. The bottom of the tank was used by the command device 12.

Furthermore, from the viewpoint of width direction accuracy, the present invention has been described with respect to the effect of L direction edging during DBT or DF rolling, but from the viewpoint of planar shape, C direction edging during DW rolling is also effective.

As explained in detail above, and as is clear from Table 1, the example of the present invention for producing a restrim steel plate had the lowest total cost for manufacturers and consumers.

On the other hand, none of the comparative examples were as good as the inventive examples.

Comparative Example 4 in which the same edge miller was used as the cutting means for bamboo was found to be totally impractical and non-industrial because the cutting allowance was large and the equipment cost was extremely high. In addition, as is clear from Table 2, when gas cutting is used to manufacture a grooved steel plate, handling equipment, personnel costs, and processing costs increase after the primary cutting, and in the end, the overall cost is superior to the example of the present invention. was not obtained, and it was found that all of the examples of the present invention yielded results that most satisfied industrial requirements in terms of both total cost and processing accuracy.

1N Open] 1r: G3-56304 (8) 1N Open Show 63-
56304 (9) (Note) (1) DAT amount = A-B [DBT rolling immediately before DW rolling or D immediately before DF rolling
Difference in longitudinal cross-sectional thickness A-B of the rolled material after DATEE rolling in W rolling (see Figure 4)] (2) Width drop = Q-D Local width fluctuation (width drop) due to unsteady deformation (see Figure 5)] (3) Initially, α has a shape ratio of (1,4-0,2β)
1/2 (Hl (= Fi2)) (4) Lubrication is carried out at a width of 50'Ow on the end side of the rolled material (5) Chamfer rolling is shown in Figure 6 (a), and the amount of chamfer is shown in a in the same figure (6) ○: Cheap △: Slightly expensive ×: High [Effects of the invention] The present invention uses Elacung roll as the primary processing. After edge processing, an edge mirror is installed to perform milling as a secondary process based on the edge processing results, and shape correction rolling and can l-controlled rolling are performed with horizontal rolls along with primary carving. As a result, the amount of cutting required has been significantly reduced, making it possible to use edge mirrors to the extreme (
F can be downsized and product manufacturing yields can be significantly improved. In addition, the occurrence of seam flaws is significantly reduced by etching, chamfer rolling, or lubricated rolling, and the amount of cutting is further reduced to virtually none, resulting in improved yields and maintenance in plate manufacturing. Not only will it be possible to reduce the occurrence rate, but it will also be possible to guarantee the edge quality of the steel plate required for the production of IJ or no-trim steel plates. ) The production cost will be significantly reduced, and it will be possible to connect manufacturers and consumers to provide the most technically and economically superior products.

[Brief explanation of the drawing]

2! '7 Figure 1 shows an example of the relationship between the total welding direction edging amount and width deviation (steady part), and Figure 2 shows the width drop amount and DWaE extension when the total welding direction edging amount is fixed at 70 MJIK. A diagram showing an example of the relationship between the DAT amount of DAT rolling and the DAT amount in the immediately preceding DBT rolling.
Crop area when DAT amount in rolling is low and DA of DAT rolling in DW rolling immediately before DF rolling
A diagram showing an example of the relationship with the T amount, Figures 4 and 5 are DA
Diagram explaining the T amount and width drop amount, Figure 6 (a), (b) Schematic diagram of the surface leveling device for the H corner part, Figure 7 (a), (b), (c) is the rolled material Figure 8 is a plan layout diagram showing the configuration of one implementation line of the present invention. Agent Patent Attorney Masamoto Akizawa et al. DAT + (am) 71 at 23rd DW '4 Figure Outside 5 Figure 71-υ Ward (θ) (b) d'Yoshi roll 77 times

Claims (3)

[Claims] (1) At least one pair of horizontal rolls and one pair of vertical rolls are arranged to perform shape adjusting rolling and widening rolling of the material to be rolled, and if necessary, shape correcting rolling and finishing rolling of one or both of the above rolling steps. , When producing a thick steel plate by subsequently cutting the end face of the rolled material, edging the longitudinal ends of the rolled material by a total of at least 70 mm in finish rolling, and shape correction in shape adjustment rolling immediately before width rolling. In addition, when the shape ratio α is the width ratio β in the finish rolling, 1.4-0.2β), the inflection is achieved by at least one pass of edging before and/or after the horizontal pass in which the material to be rolled has an end face shape with an inflection point due to width expansion. A method for manufacturing a rest rim steel plate, characterized by correcting points. (2) At least one pair of horizontal rolls and one pair of vertical rolls are arranged to perform shape adjusting rolling and widening rolling of the material to be rolled, and if necessary, shape correcting rolling and finishing rolling of one or both of the above rolling steps. , When producing a thick steel plate by subsequently cutting the end face of the rolled material, edging the longitudinal ends of the rolled material by a total of at least 70 mm in finish rolling, and shape correction in shape adjustment rolling immediately before width rolling. In addition, when the shape ratio α is the width ratio β in the finish rolling, 1.4-0.2β), at least one pass of the corner of the rolled material before and/or after the horizontal pass in which the rolled material has an end face shape with an inflection point due to width expansion. A method for manufacturing a rest trim steel sheet, characterized in that the inflection point is eliminated by partial chamfer rolling. (3) At least one pair of horizontal rolls and one pair of vertical rolls are arranged to perform shape adjusting rolling and widening rolling of the material to be rolled, and if necessary, shape correcting rolling and finishing rolling of one or both of the above rolling steps. , When producing a thick steel plate by subsequently cutting the end face of the rolled material, edging the longitudinal ends of the rolled material by a total of at least 70 mm in finish rolling, and shape correction in shape adjustment rolling immediately before width rolling. In addition, when the shape ratio α is the width ratio β in the finish rolling, 1.4-0.2β), in a horizontal pass in which the material to be rolled has an end face shape with an inflection point due to width expansion, or in this horizontal pass and previous horizontal passes, the horizontal roll and the material to be rolled A method for manufacturing a rest trim steel sheet, characterized in that the formation of the inflection point is prevented by lubricated rolling between.