JP6365626B2 - Slab shape adjustment method - Google Patents

Description

  The present disclosure relates to a method for adjusting the shape of a slab.

In general, on the entry side of a hot-rolled steel sheet production line (hot strip mill) at the finishing mill, in order to stabilize the sheet passing (conveyance of the material to be rolled) during finish rolling, the leading and tail ends of the sheet bar are rough. The unsteady deformation part called a crop part formed in the rolling process is cut. Here, the sheet bar refers to a steel plate in a state after completion of rough rolling and before finish rolling.
The front end portion and the tail end portion of the sheet bar are deformed into various shapes by a width reduction press by a sizing press, a width rolling by a width rolling mill, a horizontal rolling by a rough rolling mill, or the like.

Among these, a planar shape in which the vicinity of the center in the sheet width direction extends longer in the rolling direction than the end in the sheet width direction is called a tongue shape, and the end in the sheet width direction in the rolling direction rather than the center in the sheet width direction. A long planar shape is called a fishtail shape.
If the shape of the cropped part is asymmetrical in the plate width direction with the center in the plate width direction as the center axis, if the sheet bar is passed through the finishing mill as it is, both ends of the sheet bar in the plate width direction Then, since an uneven load may occur in the finish rolling roll, meandering of a sheet bar or a steel plate as a material to be rolled occurs during finish rolling. Further, since the heat escapes from the three surfaces of the end surface, the upper surface, and the lower surface, the temperature at the front end portion and the tail end portion of the seat bar is drastically reduced, and the temperature is lower than that in the steady portion. The portion where the temperature is low has a high deformation resistance, which causes a biting failure in the finishing mill.

In order to avoid the trouble caused by the crop portion in such a finish rolling mill, the crop portion at the front end portion and the tail end portion of the sheet bar is cut (crop cutting) after the rough rolling and before the finish rolling. By performing the crop cutting, effects such as prevention of meandering, prevention of drawing and stabilization of biting of a sheet bar or a steel plate as a material to be rolled can be obtained.
Here, it is known that the size of the crop portion at the front end portion and the tail end portion of the sheet bar is affected by the width reduction condition in the width reduction press. When the crop portion is large, it is necessary to increase the amount of cutting in crop cutting, leading to a deterioration in yield.

On the other hand, for example, in Patent Document 1, a groove having a shape opened with respect to the traveling direction of the slab is dug in a die of a sizing press so that the tip of the slab does not move backward during the width reduction pressing. And the method of making a front-end | tip part rectangular is disclosed.
Patent Document 2 discloses a method of suppressing deformation in the rolling direction of the tip portion and bringing it closer to a rectangle by pushing the slab forward during the width reduction pressing of the tip portion. According to Patent Documents 1 and 2, since the scrap portion is rectangular, the amount of cutting in crop cutting is reduced, and the yield can be improved.

  Further, Patent Document 3 discloses a technique for reducing yield loss by preforming with a width reduction press in a method of greatly reducing the sheet width by width rolling. In Patent Document 3, the front end portion or the rear end portion is pre-formed into a shape in which the plate width increases from the front end portion or the rear end portion toward the steady portion by a width reduction press, and the fishtail shape generated by width rolling is formed. It is small.

JP 2011-218441 A JP 2013-208648 A JP 2008-254034 A

  However, in the method disclosed in Patent Document 1, although the tip portion is made rectangular by preventing the tip of the slab from moving backward, if the width reduction amount in the width reduction press is large, the plate width Generation of strain concentrated in the center of the direction cannot be suppressed. For this reason, when the width reduction amount is large, the shape of the tip portion tends to be a tongue shape with a large plate surface area, and the amount of cutting in crop cutting increases, so it is difficult to suppress the deterioration of yield. .

  Moreover, in the method disclosed in Patent Document 2, the slab is pushed out to suppress the deformation of the tip portion. However, when the width reduction amount of the width reduction press increases, the slab is fixed. As a result, the deformation in the rolling direction of the tip portion becomes remarkable. For this reason, when the width reduction amount is large, the amount of cutting in the crop cutting increases, so that it is difficult to suppress the deterioration of the yield. Furthermore, even when the same width reduction press is performed on the tail end portion, deformation in the rolling direction of the tail end portion becomes significant, and it becomes difficult to suppress the deterioration of the yield.

  Furthermore, the method disclosed in Patent Document 3 is based on the premise of significant reduction by width rolling, and does not perform width reduction over the entire length in the longitudinal direction of the slab only by a sizing press. In the case of a large reduction by width rolling, since the rolling is required several times, the efficiency of the production line is greatly reduced. Furthermore, since rolling takes time because of the significant reduction by width rolling, the temperature is lowered, so that a high-load-resistant rolling mill for rolling the slab after the width reduction or rolling a low-temperature slab is required. For this reason, considering the omission of the number of processes, the reduction in the number of facilities, and the reduction in the cost of the facilities, it is desirable to perform the width reduction over the entire length of the slab using only a sizing press.

  Therefore, the present invention has been made paying attention to the above-mentioned problem, and suppresses deterioration of yield by reducing the amount of cutting in crop cutting when performing width reduction over the entire length of the slab with a sizing press. It aims at providing the shape adjustment method of the slab which can do.

  According to one aspect of the present invention, when the plate width of the slab is reduced to the first plate width by reducing the slab in the plate width direction using a mold, at both ends in the longitudinal direction of the slab. The plate width of the slab is reduced to a second plate width larger than the first plate width by pressing down the slab in the plate width direction using a mold at at least one end portion of the tip portion and the tail end portion. After the first width reduction step, the first width reduction step of reducing the plate width of the end portion to the second plate width by performing a first width reduction process for width reduction a plurality of times in the longitudinal direction. The second width that reduces the plate width of the slab to the first plate width by reducing the portion of the slab that has been subjected to the first width reduction treatment in the plate width direction using the mold. A second width reduction that reduces the plate width of the end portion to the first plate width by performing the reduction treatment a plurality of times in the longitudinal direction. Shape adjustment method of a slab, characterized in that it comprises a degree is provided.

  According to one aspect of the present invention, when width reduction is performed over the entire length of a slab with a sizing press, it is possible to suppress yield deterioration by reducing the cutting amount in crop cutting.

It is a top view which shows the typical example of the planar shape of a crop part, (a) is a top view which shows an example of a tongue shape, (b) is a top view which shows an example of a tongue shape, (c) is an example of a fishtail shape (D) is a top view which shows an example of a tongue shape, (e) is a top view which shows an example of a fishtail shape. It is a top view which shows a deformation | transformation of the slab of the rolling direction at the time of width reduction press, (a) is a top view which shows an example in case width reduction amount is less than 200 mm, (b) is in the case where width reduction amount is 200 mm or more It is a top view which shows an example. It is a side view which shows a deformation | transformation of the slab of the plate | board thickness direction at the time of width reduction press. It is a graph which shows the relationship between width reduction amount, a tongue shape, and a fishtail shape. It is a top view which shows the site | part of a slab. It is a top view which shows the shape adjustment method of the slab which concerns on 1st Embodiment, (a) is a top view which shows the state of the front-end | tip part in a 1st width reduction process, (b) is FIG. 6 in a 1st width reduction process ( The top view which shows the state after a), (c) is a top view which shows the state of the front-end | tip part in a 2nd width reduction process, (d) is the state after FIG.6 (c) in a 2nd width reduction process. The top view to show, (e) is a top view which shows the state of the front-end | tip part in the steady width reduction process. It is a top view which shows the contact length according to the shape adjustment method of a slab, (a) is the state which reduced the board width of the front end side of a slab by one width reduction process from the initial board width to the 1st board width. FIG. 6B is a plan view showing a state in which the first width reduction process is performed once in the first width reduction process and the second width reduction process is performed in the second width reduction process on the tip side of the slab. FIG. 4C is a plan view showing a state in which the first width reduction process is performed twice in the first width reduction process and the second width reduction process is performed in the second width reduction process on the tip side of the slab 2. is there. It is explanatory drawing which shows the difference in contact length by the difference in the distance which makes a slab run backward in a 1st width reduction process, (a) is a top view which shows the mode of a 2nd width reduction process in case the 1st distance is sufficiently large. (B) is a top view which shows the mode of the 2nd width reduction process in case the 1st distance is small. It is a top view which shows 1st distance. It is explanatory drawing which shows the relationship between the full length of the contact length in a 1st width reduction process, and the contact length of a 2nd width reduction process, (a) is the 1st width in case the full length of the contact length in a 1st width reduction process is long. The top view which shows the state after completion | finish of a rolling-down process, (b) is a top view which shows the state which performed the 2nd width reduction process once after Fig.10 (a), (c) is the contact length in a 1st width reduction process FIG. 10D is a plan view showing a state after the end of the first width reduction process in the case where the overall length is short, and FIG. 10D is a plan view showing a state in which the second width reduction process is performed once after FIG. It is a top view which shows the shape adjustment method of the slab which concerns on 2nd Embodiment, (a) is a top view which shows the state of the front-end | tip part in a steady width reduction process, (b) is the state of the front-end | tip part in a 1st width reduction process FIG. 11C is a plan view showing the state after FIG. 11B in the first width reduction process, FIG. 11D is a plan view showing the state of the tip in the second width reduction process, and FIG. ) Is a plan view showing a state after FIG. 11D in the second width reduction step. It is a top view which shows the contact length according to the shape adjustment method of a slab, (a) is the state which reduced the board width of the front end side of a slab by one width reduction process from the initial board width to the 1st board width. (B) shows the state which performed the 1st width reduction process of the 1st width reduction process in the 1st width reduction process, and the 2nd width reduction process in the 2nd width reduction process on the tail end side of a slab. It is a top view. It is a top view which shows the influence which 2nd distance has on the deformation | transformation of a tail part, (a) is a top view which shows the mode of a 2nd width reduction process in case 2nd distance is sufficiently large, (b) is 2nd It is a top view which shows the mode of the 2nd width reduction process in case a distance is small.

  As described above, the shape of the cropped portion at the front end and the tail end, which are both ends in the longitudinal direction of the seat bar, is roughly classified into two types, a tongue shape and a fishtail shape. FIG. 1 shows a representative example of the planar shape (contour) of the crop portion in the sheet bar 1. As shown in FIG. 1 (a), the tongue shape has a longitudinal direction (on the paper surface of FIG. 1) in which the center of the plate width direction is the rolling direction rather than the end in the plate width direction (left and right direction on the paper surface of FIG. 1). It has a planar shape extending long in the vertical direction). Moreover, as shown in FIG.1 (b), a tongue shape may become a shape where the edge part was dented. On the other hand, as shown in FIG. 1C, the fishtail shape has a planar shape in which the end portion extends longer in the longitudinal direction than the center portion.

  In the following description, as shown in FIG. 1 (a), in the end portion of the tongue shape, the end portion in the longitudinal direction is referred to as the end portion 1A, which is the start position of the unsteady width portion. Is called the root 1B. Further, the length in the longitudinal direction from the end 1A to the root 1B is referred to as a tongue length. At this time, in the tongue shape with the recessed tip as shown in FIG. 1B, there are two end portions in the substantially plate width direction. In this case, the end portion having the shorter length to the root portion 1B is defined as the end portion 1A. On the other hand, as shown in FIG. 1 (c), in the end portion of the fishtail shape, the end portion in the longitudinal direction is referred to as the end portion 1C, and is the most recessed in the longitudinal direction at the center portion in the plate width direction. The portion is referred to as the most concave portion 1D. In addition, the length in the longitudinal direction from the most end portion 1C to the most concave portion 1D is referred to as a fishtail length.

  Depending on the conditions of the rough rolling process, the planar shape of the cropped portion is as shown in FIG. 1 (d) and FIG. May become asymmetrical. In the case of the asymmetric fishtail shape as shown in FIG. 1 (e), the longitudinal direction at the end portion having the shortest distance in the longitudinal direction from the most concave portion 1D among the two end portions substantially present in the width direction. Let the most end be the end 1C.

  When the width reduction press is performed on the front end portion and the tail end portion of the slab with the sizing press, the front end portion and the tail end portion of the slab are deformed in the longitudinal direction and the thickness direction perpendicular to the longitudinal direction and the plate width direction. In FIG. 2, the state of the front-end | tip part after a deformation | transformation at the time of performing the width reduction press from which width reduction amount differs with respect to the front-end | tip part of the slab 2 with a board width of 1500 mm and a board thickness of 260 mm is shown. FIG. 2A shows a case where the width reduction amount is less than 200 mm, and FIG. 2B shows a case where the width reduction amount is 200 mm or more. The sizing press has a pair of molds 3a and 3b provided opposite to each other in the sheet width direction of the slab 2, and the pair of molds 3a and 3b is moved to the center of the sheet width of the slab 2 disposed therebetween. By doing so, the slab 2 is pressed in the width direction. When the width reduction shown in FIG. 2 (a) is performed with a width reduction of less than 200 mm, the deformation of the slab 2 in the longitudinal direction (the left-right direction with respect to the paper surface in FIG. 2), which is the rolling direction, Only deforms. On the other hand, in the case of performing a width reduction press with a width reduction amount of 200 mm or more shown in FIG. 2B, strain penetrates to the center portion in the plate width direction, so that the center portion in the plate width direction is large in the longitudinal direction of the slab 2. Deforms greatly.

  FIG. 3 shows an example of the shape of the tip portion after deformation in the thickness direction in the case of the example shown in FIGS. 2 (a) and 2 (b). FIG. 3A shows a case where the width reduction amount is less than 200 mm as in FIG. 2A, and FIG. 3B shows a case where the width reduction amount is 200 mm or more as in FIG. 2B. Each is shown. When performing a width reduction press with a width reduction amount of less than 200 mm shown in FIG. 3A, both end portions in the plate width direction are deformed also in the plate thickness direction, and only both end portions in the plate width direction are thickened. In the horizontal rolling performed after the width reduction press, both end portions in the sheet width direction having increased thickness are stretched in the rolling direction. Therefore, when performing the width reduction press with a width reduction amount of less than 200 mm, the tip portion of the slab 2 is fish. Tail shape. On the other hand, when the width reduction shown in FIG. 3B is performed with a width reduction amount of 200 mm or more, the central portion in the plate width direction is thickened. In the horizontal rolling performed after the width reduction press, the thickened center portion in the sheet width direction is stretched in the rolling direction. Therefore, when the width reduction amount is 200 mm or more and less than 300 mm, the tip portion of the slab 2 is used. The fishtail length is shortened. Furthermore, when performing the width reduction press whose width reduction amount is 300 mm or more, the shape of the front-end | tip part of the slab 2 becomes a tongue shape.

  That is, when considering the deformation in the rolling direction and the plate thickness direction, when the width reduction amount is less than 200 mm, the shape of the tip portion of the slab 2 after the width reduction press becomes a fish tail shape, and the fish tail length increases as the width reduction amount increases. Lengthens. When the width reduction amount is 200 mm or more and less than 300 mm, the shape of the tip portion of the slab 2 after the width reduction press becomes a fishtail shape, but the fishtail length decreases as the width reduction amount increases. When the width reduction amount is 300 mm or more, the shape of the tip portion of the slab 2 after the width reduction press becomes a tongue shape, and the tongue length increases as the width reduction amount increases. FIG. 4 shows a graph showing the relationship between the width reduction amount, the fishtail shape, and the tongue shape. The positive side of the vertical axis in FIG. 4 represents the tongue length, and the absolute value on the negative side of the vertical axis represents the fishtail length.

Moreover, since the deformation in the rolling direction and the plate thickness direction is caused by distortion in the central portion in the plate width direction, the deformation becomes more significant as the plate width of the slab 2 becomes narrower. In particular, in the case of the slab 2 having a plate width of 1500 mm or less, the deformation of the central portion in the plate width direction appears significantly.
Furthermore, although the deformation | transformation in the front-end | tip part of the slab 2 was demonstrated, such a deformation | transformation can occur similarly in a tail end part.

  As described above, when the width reduction amount in the width reduction press increases, the tongue length at both ends in the longitudinal direction of the sheet bar increases. When the tongue length is large, the yield deteriorates due to an increase in the cutting amount (crop weight) in scrap cutting performed before finish rolling. On the other hand, as a result of intensive studies on the shape adjustment method (width reduction method) of the slab 2 capable of reducing the crop weight under the condition that the width reduction amount in the width reduction press is large, the present inventors have made an investigation into the present invention. It came to know the shape adjustment method of the slab 2 which concerns.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

<First Embodiment>
[Method for producing hot-rolled steel sheet]
The shape adjustment method of the slab 2 according to the first embodiment of the present invention is applied to the width reduction press of the slab 2 performed in the rough rolling process in the manufacturing process of the hot-rolled steel sheet. The manufacturing process of a hot-rolled steel sheet is a process which manufactures a steel strip from the slab 2, and is divided roughly into a heating process, a rough rolling process, a finish rolling process, a cooling process, and a winding process in order of a process. Hereinafter, the heating process side will be described as the upstream side, and the winding process side will be described as the downstream side.

In the heating process, the slab 2 is heated to 1100 ° C. to 1300 ° C. in a heating furnace, extracted on the table, and then transported to the facility where the subsequent rough rolling process is performed.
In the rough rolling step, width rolling and horizontal rolling are performed by a width rolling mill and a rough rolling mill each provided with at least a pair of rolls on the slab that has been conveyed. The width rolling mill is provided on at least one of the upstream side and the downstream side of the rough rolling mill. Width rolling and horizontal rolling are performed while being conveyed (forwardly) in the forward direction from the upstream process side to the downstream process side, and while being conveyed (reversely running) in the reverse direction that is the reverse direction of the forward direction. There are cases. Furthermore, in the rough rolling process, when the width rolling and horizontal rolling are performed while the slab 2 is sequentially fed, and when the width rolling and horizontal rolling are performed while the slab 2 is repeated the forward feeding and the reverse running twice or more times. There is. When the width rolling and the horizontal rolling are performed only by progressive feeding, in the rough rolling process, the slab 2 is formed into a sheet bar 1 having a predetermined plate width and thickness by a rolling process using the width rolling mill and the rough rolling mill.

  In the rough rolling process, a sizing press for controlling the shape of the slab 2 by pressing the slab 2 in the width direction is installed further upstream of the rough rolling mill. This sizing press is used when the width of the slab 2 is greatly reduced (width reduction press) because the width reduction efficiency of the slab 2 is higher than that of the width rolling mill. In the first embodiment, before the width rolling by the width rolling machine, the width reduction press by this sizing press is performed. The sizing press includes a pair of molds 3a and 3b arranged opposite to each other in the plate width direction of the slab 2, and pinch rolls (not shown) provided on the upstream side and the downstream side of the pair of molds 3a and 3b. Have. The sizing press moves the pair of molds 3a, 3b in the plate width direction while intermittently transporting the slab using a pinch roll, and reduces the plate width of the slab 2 by reducing the slab 2 in the plate width direction. To do. The pinch roll can transport the slab 2 in the forward direction from the upstream process side to the downstream process side (forward feeding) and the reverse direction of the forward direction (reverse running). The pair of molds 3a and 3b includes, on the contact surface with the slab 2, a portion parallel to the conveying direction of the slab 2 on the downstream process side, and an inclined portion inclined at a predetermined angle to the conveying direction of the slab 2 on the upstream process side. Have The pair of molds 3a and 3b are arranged so that the contact surfaces face each other.

  The size of the slab 2 used in the rough rolling process is a general one having a plate width of 600 mm to 2500 mm. The width reduction by the sizing press is more than 0 mm and 400 mm or less. When the load resistance of the sizing press is large or when the taper angle of the pair of molds 3a and 3b is large, the width reduction amount of the sizing press may be more than 400 mm and 600 mm or less.

  In the width reduction press by the sizing press, after the slab 2 is conveyed (conveyed) at a predetermined conveyance pitch, the slab 2 disposed between the pair of molds 3a and 3b is transferred by the pair of molds 3a and 3b. The area is reduced to a predetermined plate width (width reduction process). In the conveyance process, the slab 2 can be moved forward or backward by the forward rotation operation or the reverse rotation operation of the pinch roll. The conveyance pitch is a moving distance when the slab 2 moves forward or backward by a single conveyance process by a pinch roll, and the length of the slab 2 in the longitudinal direction depends on the shape and size of the pair of molds 3a and 3b. It is set to a shorter length. And the conveyance reduction process and width reduction process of this slab 2 are repeated, and the width reduction press of the slab 2 is performed over the full length of a longitudinal direction.

Target width reduction amount dW _P is the width reduction amount by the width reduction process in the width reduction press, a plate width of pressure before pressing the slab 2, is determined by the product plate width of the hot-rolled steel sheet. At this time, the sheet width after the width reduction press is predicted from the initial sheet width of the slab 2, the sheet width after the horizontal rolling and the width rolling in the subsequent rough rolling process is predicted, and further thereafter predicts the plate width after applying the finish rolling, the finally predicted plate width is such that the product strip width sets the target width reduction amount dW _P. Details of the method of adjusting the shape of the slab 2 by the width reduction press will be described later.

In the finish rolling step, horizontal rolling is performed on the roughly rolled sheet bar 1 using a finish rolling mill provided with at least one horizontal rolling mill having a pair of upper and lower rolls. The horizontal rolling at this time is performed by conveying the sheet bar 1 only in one direction.
In the cooling step, the steel plate is cooled by spraying water from both the upper and lower directions in the thickness direction of the steel plate after finish rolling being conveyed.
In the winding process, the steel sheet cooled in the cooling process is wound using a coiler to form a coil.

[Slab shape adjustment method]
Next, a method for adjusting the shape of the slab 2 according to the first embodiment will be described.
As shown in FIG. 5, the slab 2 is divided into three regions from the downstream side in the rolling direction (longitudinal direction of the slab 2) in the hot rolling process: a tip portion 2T, a steady portion 2M, and a tail end portion 2B. Further, the extreme ends in the longitudinal direction at the tip 2T and the tail end 2B are referred to as a tip 2T ₀ and a tail end 2B ₀ , respectively. The length of the slab 2 in the plate width direction (vertical direction with respect to the paper surface of FIG. 5) before the width reduction press is the initial plate width W0 [mm]. As described above, in the width reduction press, when the width reduction amount is 300 mm or more, the end portion tends to have a tongue shape. Therefore, the condition of the width reduction press is the target width reduction calculated by the following equation (1). it is preferred that the amount dW _P is not less than 300 mm. In the formula (1), W1 indicates a plate width [mm] of the slab 2 finally subjected to width reduction by a width opening pressure reduction press. In addition, when the initial plate width W0 of the slab 2 is 1500 mm or less, the end portion is likely to have a tongue shape. Therefore, as a condition for the slab 2, the initial plate width W0 is preferably 1500 mm or less.
_{dW P = W0-W1 ··· (} 1)

First, as shown in FIGS. 6 (a) and 6 (b), the plate width of the slab 2 is reduced by the slab 2 in the plate width direction of the slab 2 by a sizing press. A first width reduction treatment for reducing the width to the width W2 [mm] is performed twice in the longitudinal direction (first width reduction step). The second plate width W2 is a plate width that is larger than the first plate width W1 and smaller than the initial plate width W0. In the first width reduction step, the first width reduction process is performed on each of the two regions on the tip 2T ₀ side and the tail end 2B ₀ side of the tip 2T. In the first width reduction step, first, as shown in FIG. 6 (a), subjected to a first width reduction processing with respect to the distal end 2T ₀ side of the distal end portion 2T. In this first width reduction process, a pair of molds 3a of sizing press, by 3b, by reduction (forging) tip 2T ₀ side of the distal end portion 2T in the plate width direction, the plate width of the pressure has been places the Two plate width W2. Then, reduction that is not the tip portion 2T of tail 2B ₀ side pair of molds 3a, until the pressing position by 3b, the rolling direction in the hot rolling step (rightward with respect to the plane of FIG. 6), the slab 2 transport (Progressive). Furthermore, as shown in FIG. 6 (b), subjected to a first width reduction processing on the tail 2B ₀ side of the distal end portion 2T. In this first width reduction process, as in the case of the front end side 2T ₀ , the tail end 2B ₀ side of the front end portion 2T is reduced in the plate width direction by the pair of molds 3a and 3b, so The plate width is set to the second plate width W2. Thereafter, the tip portion 2T tip 2T ₀ side pair of molds 3a, until the pressing position by 3b, the rolling direction and the opposite direction in the hot rolling process, by a slab 2 is transported (reverse run), the first width The reduction process ends. In the first width reduction step, the plate width of the tip portion 2T is reduced to the second plate width W2 by performing the first width reduction process twice in the longitudinal direction on the tip portion 2T.

After the first width reduction step, as shown in FIGS. 6C and 6D, the plate width of the slab 2 with respect to the front end portion 2T subjected to the first width reduction processing by the sizing press. A second width reduction process is performed twice in the longitudinal direction to reduce the plate width of the slab 2 to the first plate width W1 by reducing in the direction (second width reduction step). In a second width reduction step, first, as shown in FIG. 6 (c), subjected to a second width reduction processing with respect to the distal end 2T ₀ side of the distal end portion 2T. The second width reduction process, a pair of molds 3a of sizing press, by 3b, by reduction (forging) in the sheet width direction tip 2T ₀ side of the distal end portion 2T, the plate width of the pressure has been places the One plate width W1. Then, tail 2B ₀ side of the distal end portion 2T which second width reduction process has not been applied a pair of molds 3a, is progressive until the pressing position by 3b. Furthermore, as shown in FIG. 6 (d), performing a second width reduction processing on the tail 2B ₀ side of the distal end portion 2T. In this second width reduction process, as in the case of the distal end side 2T ₀ of the distal end portion 2T, the tail end 2B ₀ side of the distal end portion 2T is reduced in the plate width direction by the pair of molds 3a and 3b. The board width of the done part is set to the first board width W1. In the second width reduction process, the plate width of the tip portion 2T is reduced to the first plate width W1 by subjecting the tip portion 2T to the second width reduction process twice in the longitudinal direction.

Note that, in the second width reduction step, the width reduction is performed so that at least the plate widths of the portions that have become the second plate width W2 in the first width reduction step become the first plate width W1. For this reason, as shown in FIG. 6 (d), in the second second width reduction process, the steady width portion 2M in which the width reduction is not performed in the first width reduction process and the plate width becomes the initial plate width W0. The region on the tip 2T ₀ side is also subjected to width reduction so that the plate width is smaller than the initial plate width W0. At this time, the tip 2T ₀ side region of the constant region 2M includes a pair of molds 3a, is the width reduction by the inclined portion of 3b.

After the second width reduction step, the plate width is the same as the first plate width W1 for the portion where the width reduction is not performed until the plate widths of the stationary portion 2M and the tail end portion 2B of the slab 2 become the first plate width W1. The width is reduced so as to be (steady width reduction step). In the steady width reduction step, first, the region on the tip 2T ₀ side is a pair of molds 3a among the places where the width reduction is not performed until the plate width of the steady portion 2M and the tail end portion 2B reaches the first plate width W1. , 3b, the slab 2 is fed in order until it reaches the reduction position. Next, as shown in FIG. 6 (e), a steady width reduction process is performed on the portion arranged at the reduction position by the pair of molds 3 a and 3 b. In this steady width reduction process, the plate width at this location is reduced to the first plate width W1 by reducing the location of the pair of molds 3a and 3b in the plate width direction. Furthermore, the width reduction press is performed over the entire length in the longitudinal direction of the slab 2 by repeatedly performing the forward feeding and the steady width reduction process of the slab 2.

  As described above, according to the method for adjusting the shape of the slab 2 according to the first embodiment, the plate width in the entire length in the longitudinal direction of the slab 2 is adjusted to the first plate width W1. As described above, when the width reduction amount of the width reduction press is large, if the width reduction from the initial sheet width W0 to the first sheet width W1 is performed by a single width reduction process, distortion occurs in the center portion of the sheet width. Therefore, the shape of the tip 2T becomes a tongue shape having a long tongue length. In contrast, in the method for adjusting the shape of the slab 2 according to the first embodiment, when the width of the tip portion 2T of the slab 2 is reduced, the width is divided into two steps, that is, the first width reduction step and the second width reduction step. Perform the reduction. As a result, the amount of width reduction by one width reduction process can be reduced, and distortion is less likely to enter the central portion in the plate width direction. Therefore, the shape of the tip 2T is changed to a tongue shape or fish with a short tongue length. It can be a tail shape.

In the first embodiment, the first width reduction step, applying a first width reduction treatment twice longitudinally relative to the tip 2T ₀ side of the slab 2. On the other hand, in the first width reduction step, when the first width reduction process is performed only once on the tip 2T ₀ side of the slab 2, the tongue suppression effect such as the reduction of the tongue length and the fishtail shape is achieved. Can hardly get. Plate width tip 2T ₀ side of the slab 2 in FIG. 7 is definitive when the width reduction until first plate width W1, shows a different contact length L _T shape adjustment method. In FIG. 7 (a), shows a state where the tip 2T ₀ side of the plate width of the slab 2, and pressure in the width reduction process once the initial strip width W0 until first plate width W1. The FIG. 7 (b), the applied once first width reduction processing on the tip 2T ₀ side of the slab 2 in the first width reduction step, then the the front end 2T ₀ side of the slab 2 in the second width reduction step The state which performed the 2 width reduction process is shown. The FIG. 7 (c), the as in the first embodiment described above, subjected to a first width reduction treatment twice to the tip 2T ₀ side of the slab 2 in the first width reduction step, then the second width reduction step in showing a state subjected to second width reduction processing portion (tip 2T ₀ side of the distal end portion 2T) including tip 2T _0. In FIG. 7A to FIG. 7C, the hatched portion is reduced by the width reduction process performed immediately before. The width reduction press, mold 3a, as the longitudinal direction of the contact length L _T of the slab 2 is prolonged for 3b, the deformation amount in the longitudinal direction of the slab 2 is large, the tongue-shaped edge shape after width reduction press If this is the case, it will contribute to the increase in tongue length. Therefore, in order to shorten the tongue length, in addition to reducing the width reduction ratio of one, it is important to shorten the contact length L _T. In the case of FIG. 7B in which the first width reduction process is performed only once in the first width reduction process, the width reduction in the second width reduction process is performed so as to overlap with the portion of the width reduction in the first width reduction process. Done. Therefore, the contact length L _T in FIG. 7 (b), becomes 7 approximately the same length as the contact length L _T in (a) to width reduction to the first plate width W1 in one width reduction process, the tongue The suppression effect cannot be obtained sufficiently. In contrast, the contact length _{L T} in FIG. 7 performing the first width reduction treatment twice in the first width reduction step (c), than the contact length _{L T} in FIGS. 7 (a), 7 (b) Is also shortened, and a tongue suppression effect can be obtained.

In the case of the first embodiment in which the first width reduction process is performed twice in the longitudinal direction in the first width reduction process, the first distance D1 for reversely running the slab after the first width reduction process in the first width reduction process is as follows. If it is small, the tongue suppression effect may not be sufficiently obtained. FIG. 8A shows the state of the second width reduction process when the first distance D1 is sufficiently large, and FIG. 8B shows the state of the second width reduction process when the first distance D1 is small. . FIG. 8 (a), when compared FIG 8 (b), the first distance D1 is shorter FIG. 8 (b), the contact length L _T of the second width reduction processing for the first time becomes longer, the first width reduction step It can be seen that the sheet width is the same as that when the sheet width is set to the first sheet width W1 (for example, as shown in FIG. 7A) without performing the above. In other words, in order to obtain a tongue suppression effect sufficiently, pressure contact length L _T of the second width reduction process, the plate width by the width reduction once without first width reduction step the first plate width W1 It is necessary to make it shorter. As shown in FIG. 9, the contact length L _TS of the portion where the inclined portions of the molds 3a, 3b are in contact with the slab 2 in the second width reduction process is calculated by the following equation (2). Note that (2) In the equation, dW _P2 is the following (3) width reduction rate of the slab 2 by the second width reduction process calculated by the formula, theta mold 3a with respect to the longitudinal direction of the slab 2, 3b of the inclined portion of the Each tilt angle is shown.

dW _P2 = W2-W1 (3)
In order to make the contact length L _TS in the second width reduction process shorter than the case where the plate width is reduced to the first plate width W1 by one width reduction without performing the first width reduction process, The one distance D1 may be longer than the contact length _LTS , and the first distance D1 only needs to satisfy the following expression (4).

In the first embodiment, the length L _T1 of the contact length in the first width reduction step preferably satisfies the expression (5). Overall length L _T1 of the contact length in the first width reduction step, the longitudinal length of the first width reduction step, the pair of molds 3a by a first width reduction treatment twice, the slab 2 that is in contact with 3b region It is. In other words, the total length L _T1 of the contact length in the first width reduction step, the pair of molds 3a by the width reduction treatment for the second time from the tip 2T _0, the longitudinal length of up to a region in contact with the inclined portion of 3b. When the contact length L _T of the first width reduction process satisfies the expression (5), as shown in FIG. 10 (a), at the end of a state immediately after the first width reduction step, the mold of the slab 2 is a one-to-3a , 3b is in contact with the parallel part. Therefore, as shown in FIG. 10 (b), it is possible to shorten the contact length L _T of the second width reduction processing of the second width reduction step. On the other hand, when the contact length L _T of the first width reduction process does not satisfy the expression (5), as shown in FIG. 10 (c), at the end of a state immediately after the first width reduction step, the slab 2 is a pair of It will be in the state which contacts only the inclination part of metal mold | die 3a, 3b, and does not contact the parallel part of a pair of metal mold | die 3a, 3b. Therefore, as shown in FIG. 10 (d), even when the first distance D1 is satisfied the equation (4), it is possible to shorten the contact length L _T of the second width reduction processing of the second width reduction step There is a possibility that the tongue suppression effect cannot be obtained.

In the first embodiment, the length L _T1 of the contact length in the first width reduction step is preferably more than half the length of the initial plate width W0, if a slab 2 of a general plate width 350mm The above is preferable. If the contact length of the total length L _T1 of the first width reduction step is less than half of the length of the initial plate width W0, the influence of the plate width center of the front end portion 2T ₀ by the constant width reduction processing increases, tongue inhibition The effect may not be obtained sufficiently.
Furthermore, in the first embodiment, the width reduction amount dW _P1 by the first width reduction process and the width reduction amount dW _P2 by the second width reduction process may be any value, but are less than 300 mm from the viewpoint of the tongue suppression effect. It is preferable that

Second Embodiment
[Slab shape adjustment method]
Next, a method for adjusting the shape of the slab 2 according to the second embodiment of the present invention will be described with reference to FIGS. The shape adjustment method of the slab 2 according to the second embodiment is applied to the width reduction press of the slab 2 performed in the rough rolling process in the manufacturing process of the hot-rolled steel sheet, as in the first embodiment. The manufacturing process of the hot-rolled steel sheet is the same as that in the first embodiment. In the second embodiment, as in the first embodiment, the slab 2 including the tip portion 2T, the steady portion 2M, and the tail end portion 2B is slabd down in the plate width direction, so that the plate width in the entire length in the longitudinal direction of the slab 2 is obtained. Is finally reduced from the initial plate width W0 to the first plate width W1.

First, as shown in FIG. 11A, the sizing press is used to reduce the width of the tip portion 2T and the steady portion 2M so that the plate width becomes the first plate width W1 (steady width reduction step). . In the steady width reduction process in the second embodiment, similarly to the steady width reduction process in the first embodiment, the width from the tip 2T ₀ to the rolling direction is repeated by repeatedly performing the steady width reduction process and the progressive feeding of the slab 2. A reduction treatment is performed. Then, by constant width reduction processing is applied to the tail 2B ₀ side of the stationary unit 2M, steady width reduction process is completed. In the state where the steady width reduction process has been completed, as shown in FIG. 11A, the region on the steady portion 2M side of the tail end portion 2B is inclined in plan view by the inclined portions of the pair of molds 3a and 3b. It will be in the state where the width was reduced in the shape.

After steady width reduction step, the plate width of the tip 2T ₀ side of the large tail end 2B than the second plate width W2, smaller than large and the initial plate width W0 than the plate width of the first plate width W1 A first width reduction process is performed to reduce the width to the second plate width W2 (first width reduction step). In the first width reduction step, first, the tip 2T ₀ side pair of molds 3a of large tail end 2B than the plate width of the second strip width W2, until the pressing position by 3b, is progressive slabs 2. Then, as shown in FIG. 11 (b), subjected to a first width reduction processing with respect to the distal end 2T ₀ side of the tail end 2B. The first width reduction process, sizing pair of molds 3a of the press, at 3b, by reduction of the distal 2T ₀ side of the tail part 2B in the plate width direction, the plate width of the pressure has been place second plate The width is set to W2. Further, the tail end 2B ₀ side pair of molds 3a of the tail end 2B, until the pressing position by 3b, is progressive slabs 2. Thereafter, as shown in FIG. 11 (c), subjected to a first width reduction processing on the tail 2B ₀ side of the tail end 2B. In this first width reduction process, the tail end 2B ₀ side of the tail end 2B is reduced in the plate width direction by the pair of molds 3a and 3b, as in the case of the tip side 2T ₀ of the tail end 2B. The plate width of the pressed portion is set to the second plate width W2. Thereafter, the tip 2T ₀ side of the tail part 2B is a pair of molds 3a, until the pressing position by 3b, and the slab 2 by causing the reverse feed, the first wide reduction process is completed. In the first width reduction step, the plate width of the tail end portion 2B is reduced to the second plate width W2 by performing the first width reduction treatment twice in the longitudinal direction on the tail end portion 2B.

After the first width reduction step, as shown in FIGS. 11 (d) and 11 (e), the plate width direction of the slab 2 with respect to the tail end portion 2B subjected to the first width reduction by a sizing press. The second width reduction process is performed twice in the longitudinal direction to reduce the plate width of the slab 2 to the first plate width W1 by pressing down to the second width reduction step (second width reduction step). In a second width reduction step, first, as shown in FIG. 11 (d), performing a first second width reduction processing on the tip 2T ₀ side of the tail end 2B. In the first second width reduction processing of the pair of molds 3a of sizing press, by 3b, by reduction of the distal 2T ₀ side of the tail part 2B in the plate width direction, the plate width of the pressure has been places the One plate width W1. Then, tail 2B ₀ side of the tail part 2B of the second width reduction process has not been applied a pair of molds 3a, it is progressive until the pressing position by 3b. Furthermore, as shown in FIG. 11 (e), with respect to the tail 2B ₀ side of the tail part 2B performs second second width reduction process. In the second second width reduction process, the tail end 2B ₀ side of the tail end 2B is pressed down in the plate width direction with the pair of molds 3a and 3b as in the case of the tip end 2T ₀ of the tail end 2B. As a result, the plate width of the reduced portion is set to the first plate width W1. In the second width reduction step, the plate width of the tail end portion 2B is reduced to the first plate width W1 by subjecting the tail end portion 2B to a second width reduction treatment twice in the longitudinal direction.

In the second width reduction step, the second width reduction process is performed over the entire length of the tail end portion 2B in the longitudinal direction, so that the plate width of the tail end portion 2B in the longitudinal direction is equal to the first plate width W1. Become. Therefore, as shown in FIG. 11 (d), the first second width reduction process for the width reduction of the distal 2T ₀ side of the tail end 2B, a portion where the first width reduction processing has not been performed, the The portion subjected to the one width reduction treatment is reduced in width. Here, the place where the first width reduction treatment is not performed means that the plate width on the tip 2T ₀ side of the tail end portion 2B is smaller than the second plate width W2 and larger than the first plate width W1. It is a region that is inclined in a plan view shown in (d).

  As described above, according to the method for adjusting the shape of the slab 2 according to the second embodiment, the plate width in the entire longitudinal length of the slab 2 is adjusted to the first plate width W1. Moreover, in the shape adjustment method of the slab 2 according to the second embodiment, when the tail end portion 2B of the slab 2 is reduced in width, similarly to the tip portion 2T of the first embodiment, the first and second width reduction steps. The width reduction is performed in two steps. As a result, the amount of width reduction in one width reduction process can be reduced, and it becomes difficult for distortion to enter the central portion of the plate width. Therefore, the shape of the tail end 2B is changed to a tongue shape or fish with a short tongue length. It can be a tail shape.

In the second embodiment, the first width reduction step, by applying a first width reduction treatment twice longitudinally relative to the tail end 2B ₀ of slab 2, it is possible to obtain a tongue suppressing effect. In the second width reduction process, when the second width reduction process is performed only once on the tail end 2B ₀ side of the slab 2, it is almost possible to obtain a tongue suppression effect such as a reduction in tongue length and a fishtail shape. Can not. Plate width tail 2B ₀ side in FIG. 12 is definitive when the width reduction until first plate width W1, shows a different contact length L _T shape adjustment method. The FIG. 12 (a), the shows the state in which the tail end 2B ₀ side of the plate width of the slab 2, and pressure in the width reduction process once the initial strip width W0 until first plate width W1. In FIG. 12B, the second plate is subjected to the second width reduction process once in the longitudinal direction in the second width reduction process on the region on the tail end 2B ₀ side subjected to the first width reduction process. The state where it is reduced from the width W2 to the first plate width W1 is shown. In FIG. 12A and FIG. 12B, the portion indicated by hatching is reduced by the width reduction process performed immediately before. In the second width reduction process, in the case of FIG. 12B in which the second width reduction process is performed only once, the contact length _TL is reduced to the first plate width W1 by one width reduction process. the length of the same extent as the contact length L _T in (a). That is, if the second width reduction process in the second width reduction process is performed only once as shown in FIG. 12B, the tongue suppression effect cannot be sufficiently obtained. On the other hand, according to the shape adjustment method of the slab 2 according to the second embodiment, the contact length _TL in the second width reduction process can be shortened, so that a tongue suppression effect can be obtained.

Further, in the second embodiment, the end 2T ₀ side end of the tail end 2B, which is the position where the first width reduction process is first performed, may be determined by any method. For example, the distal end 2T ₀ side end of the tail end portion 2B is a distance when the slab 2 is intermittently conveyed in the longitudinal direction by the number of times the first width reduction process is performed in the longitudinal direction (twice in the second embodiment). in a distance obtained by multiplying the monkey conveying pitch D [mm], it may be a position away from the tail end 2B _0. Furthermore, the tip 2T ₀ end of the tail portion 2B, the first width reduction step may be determined by predicting the length of the slab 2 extending in the longitudinal direction. When the second distance D2, which is the length in the longitudinal direction of the region subjected to the first width reduction process in the first width reduction process, is short, the tail end 2B is deformed due to the influence of the steady width reduction process, and is sufficiently In some cases, it is not possible to obtain an effective tongue suppression effect. FIG. 13A shows the state at the end of the steady width reduction process when the second distance D2 is sufficiently long, and FIG. 13B shows the state at the end of the steady width reduction process when the second distance D2 is short. Each state is shown. Here, the second distance D2 is the length of the region where the width reduction from the initial plate width W0 to the second plate width W2 is performed in the first width reduction step, and no reduction is performed in the steady width reduction step. It is the length of the area that is not. When the second distance D2 is sufficiently long as shown in FIG. 13A, the tail end 2B is not deformed by the steady width reduction process, but the second distance as shown in FIG. 13B. When D2 is short, the tail end 2B may be deformed by the steady width reduction process. However, as shown in FIG. 13A, when the second distance D2 is sufficiently long, the tail end portion 2B is not deformed in the steady width reduction process. Here, as the second distance D2 that does not affect the deformation of the tail end 2B, it is known that the second distance D2 satisfies the following expression (6). In the second embodiment, the tongue suppression effect can be obtained more reliably by making the second distance D2 satisfy the expression (6).

In the second embodiment, like the first embodiment, the length L _T1 of the contact length in the first width reduction step is preferably more than half the length of the initial plate width W0, common plate If it is width slab 2, it is preferred that it is 350 mm or more. If the total length L _T1 of the contact length in the first width reduction step is less than half of the length of the initial plate width W0, the influence of the plate width central tail portion 2B ₀ by the constant width reduction processing is increased, the tongue There is a possibility that a sufficient suppression effect cannot be obtained.
Further, in the second embodiment, as in the first embodiment, the width reduction amount dW _P1 by the first width reduction processing and the width reduction amount dW _P2 by the second width reduction processing may be any value, but the tongue From the viewpoint of the suppression effect, it is preferably 300 mm or less.

<Modification>
Although the present invention has been described above with reference to specific embodiments, it is not intended that the present invention be limited by these descriptions. From the description of the invention, other embodiments of the invention will be apparent to persons skilled in the art, along with various variations of the disclosed embodiments. Therefore, it is to be understood that the claims encompass these modifications and embodiments that fall within the scope and spirit of the present invention.

For example, in the first embodiment, the tip portion 2T is subjected to the first and second width reduction processes twice in the longitudinal direction in the first and second width reduction processes, but the present invention is limited to such an example. Not. In the first and second width reduction steps, the number of times the first and second width reduction processes are performed in the longitudinal direction may be three or more. At this time, the length of the tip 2T subjected to the first and second width reduction processes may be longer than that of the first embodiment. In the case of a sizing press having a general size, when the number of times the first and second width reduction processes are performed in the longitudinal direction is 4 times or more, the first and second width reduction processes are performed after the fourth time. point, because the distance from the tip 2T ₀ slab 2 is far, there is little effect on the change in shape of the distal end portion 2T be width reduction. That is, in the case of a sizing press having a general size, if the number of times the first and second width reduction processes are performed in the longitudinal direction is three times or more, the tongue suppression effect is almost equal. The number of times the width reduction treatment is performed in the longitudinal direction is preferably 2 or 3 times. Furthermore, from the viewpoint of the efficiency of the sizing press, the number of presses in the width reduction process (the number of times the width reduction process is performed with the pair of molds 3a and 3b) is preferably small, and the efficiency decreases as the number of presses increases. It becomes. For this reason, it is more preferable that the number of times that the first and second width reduction processes are performed in the longitudinal direction is two each in consideration of the compatibility between the tongue suppression effect and the efficiency. When the first width reduction process is performed n (n is an integer of 2 or more) times in the first width reduction process, the first distance D1 in the first embodiment is the first width reduction process in the first width reduction process. Is the distance to which the slab 2 is conveyed after n times. For this reason, even when the first width reduction process is performed three times or more in the first width reduction process, the first distance D1 calculated in the same manner as in the first embodiment satisfies the expression (4). contact length L _TS in the second width reduction processing by is shortened, it is possible to obtain a high tongue suppressing effect. Further, when the first width reduction processing in the first width reduction step performed n times, the total length L _T1 of the contact length in the first width reduction step is represented by the following equation (7) using a conveying pitch D. (7) In the formula, _{L 1} represents a contact length _{L T} of the time width reduction processing for the first time. Then, it is possible to contact length of the total length L _T1 is, obtain a high tongue suppressing effect than that satisfying the expression (5) in the first width reduction process represented by the equation (7).
L _T1 = (n−1) × D + L ₁ (7)

In the second embodiment, the tail end portion 2B is subjected to the first and second width reduction processes twice in the longitudinal direction in the first and second width reduction processes. It is not limited to. In the first and second width reduction steps, the first and second width reduction processes may be performed three times or more in the longitudinal direction. At this time, the length of the tail end portion 2B subjected to the first and second width reduction processes may be longer than that in the case of the first embodiment. In the case of a sizing press having a general size, when the number of times the first and second width reduction processes are performed in the longitudinal direction is 4 times or more, substantially the same tongue suppression effect can be obtained. In the case of a sizing press having a general size, when the number of times the first and second width reduction processes are performed in the longitudinal direction is 5 times or more, the first and second width reduction processes are performed after the fifth time. that point, because the distance from the tail end 2B ₀ slab 2 is far, there is little effect on the change in shape of the tail part 2B be width reduction. In other words, in the case of a sizing press having a general size, if the number of times the first and second width reduction processes are performed in the longitudinal direction is four times or more, the effect of suppressing the tongue is almost the same. The number of times the width reduction treatment is performed in the longitudinal direction is preferably 2, 3, or 4. Furthermore, from the viewpoint of efficiency of the sizing press, the number of times of performing the first and second width reduction treatments in the longitudinal direction is more preferably 2 times or 3 times in consideration of the compatibility between the tongue suppression effect and the efficiency. .

Furthermore, in the first and second embodiments, the number of times that the first width reduction process is performed in the longitudinal direction in the first width reduction process and the number of times that the second width reduction process is performed in the longitudinal direction in the second width reduction process. However, the present invention is not limited to this example. The number of times that the first width reduction process is performed in the longitudinal direction in the first width reduction process and the number of times that the second width reduction process is performed in the longitudinal direction in the second width reduction process are different as long as each is a plurality of times. It may be.
Furthermore, in the first and second embodiments, in the first width reduction process of the first width reduction step, the plate width is reduced from the initial plate width W0 to the second plate width W2 by one reduction. The present invention is not limited to such an example. For example, the plate width may be reduced from the initial plate width W0 to the second plate width W2 by performing multiple reductions on the same location in the longitudinal direction of the slab 2.

  Moreover, in the said 1st and 2nd embodiment, it was set as the structure which made the location which performs the width reduction twice of the plate width direction of the slab 2 into the front-end | tip part 2T or the tail end part 2B, but this invention is limited to this example. Not. The place where the width reduction of the slab 2 is performed twice in the plate width direction may be both ends of the tip portion 2T and the tail end portion 2B, or at least one of the tip portion 2T and the tail end portion 2B and the stationary portion 2M. . When the width reduction in the plate width direction is performed twice on both ends of the distal end portion 2T and the tail end portion 2B, first, the first and second width reduction steps are performed on the distal end portion 2T, and the plate width of the distal end portion 2T is determined. Is the first plate width W1. Next, a steady width reduction process is performed on the steady portion 2M, and the plate width of the steady portion 2M is set to the first plate width W1. Furthermore, the 1st and 2nd width reduction process is performed with respect to the tail end part 2B, and let the board width of the tail end part 2B be the 1st board width W1. In this case, the second plate width W2 at the distal end portion 2T and the second plate width W2 at the tail end portion 2B may be different plate widths. In addition, when the width reduction in the plate width direction is performed twice on at least one of the tip end portion 2T and the tail end portion 2B and the stationary portion 2M, the above-described first embodiment, the second embodiment, or both ends described above are performed twice. When performing the width reduction, the first and second width reduction steps are performed also for the steady portion 2M. From the viewpoint of efficiency, it is preferable that the portion where the width reduction in the plate width direction is performed twice is at least one of the tip end portion 2T and the tail end portion 2B.

  Furthermore, in the said 1st and 2nd embodiment, although the final board width of the slab 2 after the width reduction press was made into the 1st board width W1 uniform over the longitudinal direction, this invention is not limited to this example. When the width reduction press is performed under different conditions for the tip portion 2T, the steady portion 2M, and the tail end portion 2B, the plate thickness distribution in the plate width direction is different in each part. In this case, in the horizontal rolling performed after the width reduction pressing, the behavior of the width expansion in the plate width direction when rolling is different in each part, so the plate width may not be uniform. For this reason, you may change the final board width of the slab 2 after a width reduction press to a longitudinal direction according to the width expansion behavior resulting from board thickness distribution.

Furthermore, in the said 1st and 2nd embodiment, although the location where width reduction is carried out by the 1st width reduction process and the location where width reduction is carried out by the 2nd width reduction process are the same locations, this invention starts. It is not limited to examples. In the width reduction press, if the plate width of the entire length of the slab 2 is finally the first plate width W1, a location where the width is reduced in the first width reduction step and a location where the width is reduced in the second width reduction step Is not necessarily the same part.
Furthermore, in the said 1st and 2nd embodiment, although the slab 2 used as a hot-rolled steel plate was made into object, this invention is not limited to this example. The present invention can also be applied to the case of adjusting the shape of the slab 2 to be another product such as a thick plate or a shape steel by width reduction.

<Effect of embodiment>
(1) The method for adjusting the shape of the slab 2 according to one aspect of the present invention is to reduce the slab 2 by using the molds 3a and 3b of the sizing press to reduce the slab 2 in the plate width direction over the entire length in the longitudinal direction. At least one of the front end 2T and the tail end 2B of the slab 2 when the plate width of at least one end of the front end 2T and the tail end 2B as both ends in the longitudinal direction is reduced to the first plate width. In the longitudinal direction, a plurality of first width reduction processes are performed in the longitudinal direction to reduce the plate width of the slab 2 to the second plate width W2 larger than the first plate width W1 by reducing the slab 2 in the plate width direction. The first width reduction step of reducing the plate width of the end portion to the second plate width W2 by applying the first width reduction step and the first width reduction step of the slab 2 after the first width reduction step The second width reduction process that reduces the plate width of the slab 2 to the first plate width W1 by reducing in the direction. A second width reduction step of reducing the plate width of the end portion to the first plate width by applying a plurality of times in the longitudinal direction, and in the second width reduction step, a second width reduction process applied a plurality of times Among these, in any second width reduction process, the part of the slab 2 where the first width reduction process is performed and the part where the first width reduction process is not performed are width-reduced.

According to the configuration of (1) above, the width reduction process is performed at least twice in the plate width direction on at least one of the tip end portion 2T and the tail end portion 2B. For this reason, since the amount of width reduction by one width reduction process can be made small, it can prevent that a distortion | strain enters into the center of a board width. For this reason, even when the width reduction amount of the width reduction press is large, it is possible to obtain a tongue suppressing effect and suppress the deterioration of the yield. Further, in the first and second width reduction processes, the contact length _TL when performing the first and second width reduction processes is shortened by performing the first and second width reduction processes a plurality of times in the longitudinal direction. Thus, a higher tongue suppression effect can be obtained.
Moreover, according to the configuration of (1) above, the width of the slab 2 is reduced by the sizing press over the entire length in the longitudinal direction of the slab 2, so that the width of the slab 2 is extended over the entire length in the longitudinal direction by performing width rolling as in Patent Document 3. Compared with the method of rolling down, the time required for width rolling can be shortened. Thereby, the number of processes can be omitted, the number of facilities can be reduced, and the cost of facilities can be reduced.

(2) In the configuration of (1) above, in the first width reduction process, the slab 2 is fed forward in the forward direction parallel to the longitudinal direction from the tail end to the tip during the multiple first width reduction processes. After the plurality of first width reduction processes, the slab is caused to run backward in the reverse direction, which is the reverse direction of the forward direction, and in the second width reduction process, the second width reduction process is performed in the forward direction. Let the slabs move forward.
(3) In the configuration of (2) above, in the first width reduction process when the tip portion 2T is width-reduced, the first distance D1 calculated by the expression (4) after the first width-reduction process multiple times. The slab 2 is made to run backward in the opposite direction by the length described above.
According to the above configuration (3), the contact length L _T, can be shorter than in the case of rolling the plate width by the width reduction once without first width reduction step the first plate width W1 It becomes like this. For this reason, a higher tongue suppression effect can be obtained.

(4) In the configuration of any one of (1) to (3) above, in the first width reduction process when the tip portion 2T is width-reduced, the number of times that the first width reduction process is performed on the tip portion 2T is twice. In the second width reduction process when the distal end portion 2T is width-reduced, the number of times the second width reduction process is performed on the distal end portion 2T is the number of times the first width reduction process is performed on the distal end portion 2T in the first width reduction process. It is equal to the number of times applied.
According to the configuration of the above (4), since the tongue suppression effect can be effectively obtained with a small number of presses, both the tongue suppression effect and the efficiency can be achieved.

(5) In any one of the configurations (1) to (4), in the first width reduction process when the tail end portion 2B is width-reduced, the tail of the slab 2 is obtained by a plurality of times of the first width reduction process. the second distance D2 or more in length that is calculated from the end 2B ₀ in the longitudinal direction (6) to the width reduction.
According to the configuration of (4) above, since the deformation of the tail end portion 2B due to the steady width reduction processing of the steady portion 2M can be suppressed, a higher tongue suppression effect can be obtained.

(6) In the configuration of any one of (1) to (5) above, in the first width reduction step when the tail end portion 2B is width-reduced, the number of times the first width reduction process is performed on the tail end portion 2B. In the second width reduction step when the tail end portion 2B is width-reduced twice or three times, the number of times of applying the second width reduction process to the tail end portion 2B is the tail end portion in the first width reduction step. It is equal to the number of times that the first width reduction process is performed on 2B.
According to the configuration of the above (5), since the tongue suppression effect can be effectively obtained with a small number of presses, both the tongue suppression effect and the efficiency can be achieved.

(7) In any one of the configurations (1) to (6), the width reduction amount of the plate width of the slab 2 in the first width reduction step and the width reduction of the plate width of the slab 2 in the second width reduction step. The target width reduction amount, which is the total width reduction amount with the amount, is set to 300 mm or more.
According to the configuration of (7) above, a high tongue suppression effect can be obtained under the condition of the width reduction amount in which the shape of the end portion of the seat bar tends to be a tongue shape having a long tongue length.

(8) In any one of the configurations (1) to (7), in the first width reduction process, the plate width of the slab 2 before the first width reduction process is set to 1500 mm or less.
According to the configuration of (8) above, a high tongue suppression effect can be obtained under the slab 2 dimensional condition in which the shape of the end portion of the seat bar tends to be a tongue shape having a long tongue length.
(9) In any one of the configurations (1) to (8), when the width of the second plate width W2 and the tail end 2B are reduced in the first width reduction step when the tip portion 2T is reduced in width. The second plate width W2 in the first width reduction step is a different plate width.
Usually, when the width is reduced by the width reduction press, due to the difference in the reduction conditions such as the shapes of the molds 3a and 3b, the amount of deformation at the tip portion 2T and the tail end portion 2B even with the same width reduction amount, The shape after deformation is different. On the other hand, according to the configuration of the above (9), the optimal second plate width W2 can be set for each of the tip end portion 2T and the tail end portion 2B according to the reduction condition, and a higher tongue suppression effect can be obtained. Can be obtained.

(10) In the configuration according to any one of (1) to (9), the slab 2 is moved in the plate width direction at a portion where the width is not reduced in the first width reduction step and the second width reduction step of the slab 2. It further includes a steady width reduction process in which a steady width reduction process is performed a plurality of times in the longitudinal direction so that the plate width of the slab 2 is reduced to the first plate width by reducing the width once. The first width reduction process and the second width reduction process Then, the entire length in the longitudinal direction of the slab is reduced in width by the steady width reduction step.
According to the configuration of the above (10), the place where the initial plate width W0 to the first plate width W1 are performed twice under the width pressure is only the end portion 2T and the tail end portion 2B of the slab 2 only. By doing so, the efficiency of the sizing press can be increased.
(11) In any configuration of the above (1) to (10), the width reduction by the sizing press is performed downstream of the heating furnace on the hot rolling line and upstream of the rough rolling.

  Next, Example 1 performed by the present inventors will be described. In Example 1, using the method for adjusting the shape of the slab 2 according to the first embodiment, the slab 2 subjected to the width reduction press was roughly rolled over the entire length of the slab 2 in the longitudinal direction, and the slab 2 subjected to the width reduction press was roughly rolled. The dimensions of the slab 2 are a plate width of 1200 mm and a plate thickness of 260 mm. The plate thickness of the sheet bar 1 after rough rolling is 35 mm. And about the sheet | seat bar 1 after rough rolling, the crop which is a defective part of the front-end | tip part 2T was cut | disconnected, and the cut area and weight of the cut | disconnected crop were measured. In Example 1, as Comparative Example 1, width reduction pressing and rough rolling were performed under conditions different from those of the first embodiment, and crops were similarly evaluated.

  Table 1 shows the conditions of the width reduction press and the evaluation results of the crop of the tip 2T. In Table 1, the second distance D2 is the length in the longitudinal direction of the portion where the plate width is reduced from the initial plate width W0 to the second plate width W2 in the first width reduction step, as in the second embodiment. Show. As shown in Table 1, under the conditions of Examples 1-1 to 1-6, the first width reduction process was performed by changing the number of times of applying the first width reduction treatment in the longitudinal direction from 2 times to 25 times. In Example 1-1 in which the number of times of performing the first width reduction process was two, the first distance D1 was set to 300 mm. Under the conditions of Example 1-6 in which the first width reduction treatment was performed 25 times, the first width reduction treatment was performed over the entire length of the slab 2 in the longitudinal direction. In the conditions of Examples 1-1 to 1-6, the width reduction amount in the first width reduction step was 200 mm, and the width reduction amount in the second width reduction step was 200 mm. In the conditions of Examples 1-7 and 1-8, the number of times of performing the first width reduction treatment was set to twice as in Example 1-1. In the conditions of Example 1-7, the width reduction amount in the first width reduction step was 150 mm, the width reduction amount in the second width reduction step was 250 mm, and the first distance D1 was 360 mm. In the conditions of Example 1-8, the width reduction amount in the first width reduction step was 250 mm, the width reduction amount in the second width reduction step was 150 mm, and the first distance D1 was 250 mm. In the conditions of Example 1-9, the first distance D1 was 220 mm, and the other conditions were the same as in Example 1-1. In Examples 1-1 to 1-8, the first distance D1 was set to a value satisfying the expression (4), and in Example 1-9, the first distance D1 was set to a value satisfying the expression (4).

  Under the conditions of Comparative Example 1-1, the width reduction is not divided into the first width reduction process and the second width reduction process, and the steady width reduction process is performed a plurality of times over the entire length of the slab 2 as in the steady width reduction process. Thus, the initial plate width W0 was reduced to the first plate width W1 with a single reduction. Under the conditions of Comparative Example 1-2, the number of times of performing the first width reduction process was one, the width reduction amount in the first width reduction step was 200 mm, and the width reduction amount in the second width reduction step was 200 mm.

  In addition, Example 1-1 except Example 1-6 which performed the 1st width reduction process and the 2nd width reduction process over the full length of the longitudinal direction, and Comparative Example 1-1 which performed only the steady width reduction process. In the conditions of 1-5, 1-7 to 1-9 and Comparative Example 1-2, the first width reduction process and the second width reduction process are not performed. A width reduction treatment was performed. That is, in Example 1 and Comparative Example 1, the plate width of the slab 2 is 1200 mm to 800 mm over the entire length in the longitudinal direction of the slab 2 by performing the first width reduction process, the second width reduction process, and the steady width reduction process. The width was reduced until.

Under the conditions of Comparative Example 1-1, it was confirmed that the tip 2T had a tongue shape and the crop weight of the tip 2T was 72 kg. Under the conditions of Comparative Example 1-2, it was confirmed that the crop weight of the tip portion 2T was 72 kg as in Comparative Example 1-1, although the shape of the tip portion 2T was a fishtail shape.
On the other hand, under the conditions of Examples 1-1 to 1-9, the shape of the tip 2T is a fishtail shape, and the crop weight of the tip 2T is less than those of Comparative Examples 1-1 and 1-2. It was confirmed. In particular, it was confirmed that under the conditions of Examples 1-1 to 1-8 in which the first distance D1 satisfies the expression (4), the crop weight of the tip 2T is significantly reduced to 22 kg or less. Moreover, in the conditions of Examples 1-1 to 1-6, the number of times of applying the first width reduction process in the longitudinal direction was variously changed, but it was confirmed that the weight of the crop was almost the same in any condition. did. In addition, in the conditions of Example 1-9, since the first distance D1 does not satisfy the formula (4), the crop weight of the tip portion 2T increased compared to the conditions of Examples 1-1 to 1-8. As compared with Comparative Examples 1-1 and 1-2, it was confirmed that the crop weight of the tip 2T was reduced.

  Next, Example 2 performed by the present inventors will be described. In Example 2, using the method for adjusting the shape of the slab 2 according to the second embodiment, a width reduction press was performed over the entire length in the longitudinal direction of the slab 2, and the slab 2 subjected to the width reduction press was roughly rolled. The dimensions of the slab 2 are a plate width of 1200 mm and a plate thickness of 260 mm. The plate thickness of the sheet bar 1 after rough rolling is 35 mm. And about the sheet | seat bar 1 after rough rolling, the crop which is a defective part of the front-end | tip part 2T was cut | disconnected, and the cut area and weight of the cut | disconnected crop were measured. In Example 2, as Comparative Example 2, the width reduction pressing and rough rolling were performed under conditions different from those of the second embodiment, and the crop was evaluated in the same manner.

  Table 2 shows the conditions of the width reduction press and the evaluation results of the crop of the tip 2T. In Table 2, the 1st distance D1 shows the distance which makes slab 2 run backward after the 1st width reduction process was performed in the 1st width reduction process like a 1st embodiment. As shown in Table 2, under the conditions of Examples 2-1 to 2-6, the first width reduction process was performed by changing the number of times of performing the first width reduction treatment in the longitudinal direction from 2 times to 25 times. In Example 2-1, in which the first width reduction process was performed twice, the second distance D2 was set to 450 mm. Under the conditions of Example 2-6 in which the number of times of performing the first width reduction treatment was 25, the first width reduction treatment was performed over the entire length of the slab 2 in the longitudinal direction. In the conditions of Examples 2-1 to 2-6, the width reduction amount in the first width reduction step was 200 mm, and the width reduction amount in the second width reduction step was 200 mm. In the conditions of Examples 2-7 and 2-8, similarly to Example 2-1, the number of times of performing the first width reduction process was set to twice. In the conditions of Example 2-7, the width reduction amount in the first width reduction step was 150 mm, the width reduction amount in the second width reduction step was 250 mm, and the second distance D2 was 450 mm. In the conditions of Example 1-8, the width reduction amount in the first width reduction step was 250 mm, the width reduction amount in the second width reduction step was 150 mm, and the second distance D2 was 450 mm.

  Under the conditions of Comparative Example 2-1, the width reduction is not divided into the first width reduction process and the second width reduction process, and the steady width reduction process is performed a plurality of times over the entire length of the slab 2 as in the steady width reduction process. Thus, the initial plate width W0 was reduced to the first plate width W1 with a single reduction. In the condition of Comparative Example 2-2, the number of times of performing the first width reduction process is one, the width reduction amount in the first width reduction process is 200 mm, the width reduction amount in the second width reduction process is 200 mm, The distance D2 was 450 mm. Under the conditions of Comparative Example 2-3, the number of times of performing the first width reduction process was one, the width reduction amount in the first width reduction step was 200 mm, and the width reduction amount in the second width reduction step was 200 mm. Further, the second distance D2 in Comparative Example 2-3 was set to 80 mm as a value not satisfying the expression (6).

  In addition, Example 2-1 except Example 2-6 which performed the 1st width reduction process and the 2nd width reduction process over the full length of the longitudinal direction, and Comparative Example 2-1 which performed only the steady width reduction process. In the conditions of 2-5, 2-7, 8 and Comparative Examples 2-2 and 2-3, the first width reduction process and the second width reduction process are not performed. A steady width reduction treatment was applied. That is, in Example 2 and Example 2, the plate width of the slab 2 is 1200 mm to 800 mm over the entire length in the longitudinal direction of the slab 2 by performing the first width reduction process, the second width reduction process, and the steady width reduction process. The width was reduced until.

Under the conditions of Examples 2-1 to 2-8, the shape of the tail end 2B was a fishtail shape, and the crop weight of the tail end 2B was 15.5 kg or less. Moreover, in the conditions of Examples 2-1 to 2-6, the number of times of applying the first width reduction process in the longitudinal direction was variously changed, but it was confirmed that the weight of the crop was almost the same in any condition. did.
On the other hand, under the conditions of Comparative Example 2-1, it was confirmed that the shape of the tail end 2B was a tongue shape, and the crop weight of the tail end 2B was increased to 50 kg as compared with Examples 2-1 to 2-8. did. Under the conditions of Comparative Examples 2-2 and 2-3, the shape of the tail end portion 2B was a fishtail shape, but the crop weight of the tail end portion 2B was increased as compared with Examples 2-1 to 2-8. It was confirmed that the weight was 42 kg or more.

  From the results of Examples 1 and 2 above, according to the present invention, even when the width reduction amount of the width reduction press is large, the cutting amount by crop cutting can be reduced, and the deterioration of the yield can be suppressed. It was confirmed that it was possible.

DESCRIPTION OF SYMBOLS 1 Sheet bar 1A Endmost part 1B Root part 1C Outermost part 1D Outermost recessed part 2 Slab 2T Tip part 2T ₀ Tip 2M Steady part 2B Tail edge part 2B ₀ Tail edge 3a, 3b Mold W0 Initial board width W1 1st board width W2 Second plate width D1 First distance D2 Second distance

Claims (11)

By using a die of a sizing press, the slab is pressed down in the plate width direction over the entire length in the longitudinal direction, so that the plate at least one end of the tip and tail ends that are both ends in the longitudinal direction of the slab When the width is reduced to the width of the first plate,
The plate width of the slab is reduced to a second plate width larger than the first plate width by reducing the slab in the plate width direction at at least one end portion of the tip portion and the tail end portion of the slab. A first width reduction step of reducing the plate width of the end portion to the second plate width by performing a first width reduction treatment to reduce the width multiple times in the longitudinal direction;
After the first width reduction step, the portion of the slab subjected to the first width reduction treatment is reduced in the plate width direction using the mold to reduce the plate width of the slab. A second width reduction step of reducing the plate width of the end portion to the first plate width by applying a second width reduction treatment for reducing the width to the width a plurality of times in the longitudinal direction,
In the second width reduction process, among the second width reduction processes performed a plurality of times, in the second width reduction process, the location where the first width reduction process of the slab is performed, A method for adjusting the shape of a slab, wherein a portion not subjected to the first width reduction treatment is subjected to width reduction. In the first width reduction step, the slab is fed forward in a forward direction parallel to the longitudinal direction from the tail end to the tip of the slab during the plurality of times of the first width reduction treatment, After the first width reduction process, the slab runs backward in a reverse direction that is opposite to the forward direction,
2. The slab shape adjusting method according to claim 1, wherein, in the second width reduction step, the slab is sequentially fed in the forward direction during a plurality of times of the second width reduction process. In the first width reduction step when the tip portion is width-reduced, after the first width-reduction process a plurality of times, the first direction D1 is calculated by the length equal to or longer than the first distance D1 calculated by the equation (4). The slab shape adjusting method according to claim 2, wherein the slab is caused to run backward.
D1> dW _P2 / (2 · tan θ) (4)
D1: First distance [mm]
dW _P2 : Width reduction amount [mm] in the second width reduction step
θ: Mold tilt angle [degrees] In the first width reduction process when the tip portion is width-reduced, the number of times that the first width reduction process is performed on the tip portion is two times,
In the second width reduction process at the time of the width reduction of the tip portion, the number of times the second width reduction process is performed on the tip portion is the number of times the first width reduction process is applied to the tip portion in the first width reduction step. The slab shape adjusting method according to claim 1, wherein the slab shape adjusting method is equal to the number of times the slab is applied. In the first width reduction process when the tail end portion is width-reduced, a second distance D2 calculated from the tail end of the slab in the longitudinal direction by the expression (6) by a plurality of times of the first width reduction process. and the width reduction of the above length, characterized in that the target width reduction amount dW _P is a value obtained by subtracting the plate width of the slab after width reduction from the initial strip width of the slab before width reduction in (6) The slab shape adjustment method according to any one of claims 1 to 4.
_{D2> dW P / 2 ··· (} 6)
D2: Second distance [mm]
dW _P: target width reduction amount [mm] In the first width reduction process when the tail end portion is width-reduced, the number of times of applying the first width reduction process to the tail end portion is two or three times,
In the second width reduction step when the tail end portion is width-reduced, the number of times that the second width reduction process is performed on the tail end portion is the first width reduction step in the first width reduction step. It is equal to the frequency | count of performing a width reduction process, The shape adjustment method of the slab of any one of Claims 1-5 characterized by the above-mentioned.   A target width reduction amount that is a total width reduction amount of the width reduction amount of the plate width of the slab in the first width reduction step and the width reduction amount of the plate width of the slab in the second width reduction step is 300 mm. It is set as the above, The shape adjustment method of the slab of any one of Claims 1-6 characterized by the above-mentioned.   In the said 1st width reduction process, the board width of the said slab before performing the said 1st width reduction process shall be 1500 mm or less, The shape adjustment of the slab of any one of Claims 1-7 characterized by the above-mentioned. Method.   A plate width different from the second plate width in the first width reduction step when the tip portion is width-reduced and the second plate width in the first width reduction step when the tail end portion is width-reduced The slab shape adjusting method according to claim 1, wherein the slab shape is adjusted. The plate width of the slab is reduced by reducing the width of the slab once in the plate width direction at a location where the width is not reduced in the first width reduction step and the second width reduction step of the slab. Further comprising a steady width reduction step of applying a steady width reduction treatment to the plate width a plurality of times in the longitudinal direction,
The width reduction of the full length of the longitudinal direction of the said slab is carried out by the said 1st width reduction process, the said 2nd width reduction process, and the said steady width reduction process, The any one of Claims 1-9 characterized by the above-mentioned. Slab shape adjustment method.   The shape of the slab according to any one of claims 1 to 10, wherein the width reduction by the sizing press is performed on the downstream side of the heating furnace on the hot rolling line and on the upstream side of the rough rolling. Adjustment method.

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