JP4315019B2 - Hot slab plate thickness reduction method, plate thickness reduction device, and mold rotation mechanism - Google Patents

Description

  The present invention relates to a plate thickness reduction method, a plate thickness reduction device, and a mold rotation mechanism that enable a hot slab to be greatly reduced in the thickness direction by a single pass.

  In a normal rolling mill that rolls a slab between two rolling rolls, it is difficult to achieve a large reduction in one pass because of the biting angle limit. Therefore, for example, in a rough rolling line of a hot rolling process in which a hot slab having a thickness of about 250 mm is reduced to a sheet bar having a thickness of about 30 to 50 mm, usually 2 to 5 rolling mills are arranged in series. In addition, rolling for about 5 to 7 passes is carried out including reverse for rolling by reciprocating the slab. However, the installation of this equipment requires a large amount of equipment costs and the equipment length becomes long. is there.

  On the other hand, a planetary mill having a large number of planetary rolls has been proposed as a rolling means capable of large reduction in one pass. However, the planetary mill has a problem that it is not suitable for mass production type equipment because the small-diameter roll hits the material to be rolled at high speed, so the impact is large and the life of the bearings etc. is short, so frequent maintenance is required. .

  In order to solve the above-described problem, a plate thickness reduction press apparatus in which a conventional width reduction press is applied to plate thickness reduction as a hot slab reduction means capable of large reduction in one pass has been proposed (for example, patents). Reference 1, Patent Document 2, and Patent Document 3).

  FIG. 6 shows a hot slab press apparatus disclosed in Patent Document 1. This apparatus includes molds 50, 50 provided above and below the slab S, sliders 51, 51 provided for each mold to swing the mold up and down and back and forth, and driving for driving the sliders. The slider includes a main body 53, 53 provided with circular holes 52, 52 having a central axis in the slab width direction, a first shaft fitted into the circular hole, and a smaller diameter than the first shaft. The second shaft includes cranks 54 and 54 configured by shifting the first shaft and the central shaft, and the second shaft is rotationally driven by the driving device. In the hot slab press device disclosed in Patent Document 1, as disclosed in Patent Document 2, a taper portion 55 that is widened and inclined in the entrance direction with respect to the traveling direction of the slab and the taper portion are continuous. A mold having a main machining surface composed of parallel portions 56 parallel to the traveling direction is used. In these reduction methods, in order to prevent the mold and the slab from slipping during the reduction, the contact start surface of the slab and the mold is formed in the transition region between the tapered portion and the parallel portion and a part of the parallel portion. It is characterized by being.

FIG. 7 shows a plate thickness reduction device disclosed in Patent Document 3. This apparatus synchronizes slabs with dies 60, 60 having molding surfaces 61, 61 that are convexly curved in the slab traveling direction as viewed from the side of the slab traveling direction from above and below the molding material S. It is characterized in that the material to be formed is pressed in the plate thickness direction by swinging so that the portion of the forming surface in contact with the material to be formed is moved from the downstream side in the slab traveling direction to the upstream side in the slab traveling direction while being close to the traveling direction. A sheet thickness reduction method is disclosed.
Japanese Patent Application Laid-Open No. 11-239832, claims, etc. JP 2000-254702 A, Claims, etc. Japanese Patent Laid-Open No. 11-90502, claims, etc.

  However, in the conventional sheet thickness reduction press apparatus illustrated in FIGS. 6 and 7, a large reduction amount can be given to the slab in a single pass, but each has the following problems. First, in the hot slab press apparatus shown in FIG. 6 disclosed in Patent Document 1, the parallel parts of the upper and lower molds are set to be parallel to the slab S, and the molds 50 and 50 are pressed down. Accordingly, the contact area between the mold and the slab gradually increases from the contact between the slab and the mold to the bottom dead center in the plate thickness direction reduction, and it is inevitable that the reduction load increases. In order to reduce the rolling load, the contact area between the mold and the slab may be reduced, that is, the amount of feed to the downstream side of the slab between the single passes may be set small. On the other hand, as shown in Patent Document 2, in order to prevent slippage between the mold and the slab that is likely to occur at the start of rolling, the contact start surface between the slab and the mold is between the tapered portion and the parallel portion. It must be part of the transition region and the parallel part. For this purpose, the lower limit value of the feed amount to the downstream side of the slab between the single passes is naturally determined by the mold shape and the reduction amount. However, for example, if the mold inclination angle with respect to the slab traveling direction is excessively increased from this viewpoint, it is possible to set the feed amount per pass small, but there is a problem that productivity is greatly reduced.

  In the plate thickness reduction device of FIG. 7 disclosed in Patent Document 3, the molds 60 and 60 having the arc-shaped pressing surfaces 61 and 61 are squeezed while being swung, and this purpose is between the mold and the slab. Is to reduce the contact length, that is, to reduce the rolling load. However, in order to achieve this object, the device mechanism for swinging the mold becomes very complicated. Further, since the mold is swung from the downstream side in the slab traveling direction to the upstream side, the reverse amount of the material accompanying the reduction is large. In order to compensate for this, the mold must be sent to the upstream side in the slab traveling direction during the reduction by the mold back-and-forth movement mechanism, and in any case, the apparatus mechanism is inevitably complicated.

  Moreover, in the plate thickness reduction press apparatus used as intermittent processing, it is inevitable that the line speed becomes slower than rolling, and the reduction in productivity is a serious problem from the viewpoint of preventing the temperature reduction of the rolled material. However, the conventional sheet thickness pressing machine has a problem that the advanced amount is small and this problem has not been solved.

  That is, the reduction load generated when the slab is reduced in the plate thickness direction can be simply obtained by Expression (1).

P = Qp · k · lm · W (1)
Qp is a rolling force function, and is determined by a plate thickness rolling condition such as a slab thickness, a rolling amount, and a friction coefficient between a mold and a slab. K is the deformation resistance of the slab, lm is the contact length between the mold and the slab, and W is the slab width. From equation (1), as a substantial means for reducing the rolling load, (a) reducing the rolling force function Qp, (b) reducing the deformation resistance k, (c) reducing the contact arc length 1 m. , Etc. In order to reduce the rolling force function Qp, it is effective to reduce the coefficient of friction between the mold and the slab by lubrication, which is a means that is conventionally used in hot rolling and hot forging. In order to reduce the deformation resistance k, it is effective to increase the slab temperature at the time of rolling down and slow down the rolling speed, but considering the heating energy and productivity, etc. It is difficult to greatly reduce k. On the other hand, in order to reduce the contact arc length of 1 m, for example, in rolling, if the rolling roll diameter is made as small as possible, as long as the biting property, the rolling roll surface strength, and the cross-sectional shape of the material to be rolled are maintained. Well, small diameter rolling rolls are often used for this purpose.

  In the forging process in which the hot slab is reduced in the plate thickness direction, as disclosed in Patent Document 3, it is possible to reduce the contact arc length of 1 m by swinging the mold during the reduction. At this time, in Patent Document 3, the mold is swung so that the portion of the convex curved surface that is in contact with the material to be molded is moved from the downstream side in the slab traveling direction to the upstream side in the slab traveling direction. In the processing method, there is a problem that the plastic flow of the material toward the upstream side in the slab traveling direction becomes large, and the reverse amount of the material accompanying the reduction increases. Under plate thickness pressure by forging, there is a point where the relative speed between the mold and the workpiece is 0 (hereinafter referred to as the neutral point), and the material located upstream of the slab from the neutral point is upstream of the slab. That is, since the deformation occurs backward with respect to the slab traveling direction, the displacement amount due to the backward deformation is referred to as a reverse movement amount. In addition, since the material located downstream of the slab with respect to the neutral point is deformed forward with respect to the downstream side of the slab, that is, with respect to the slab traveling direction, the amount of displacement due to this forward deformation is called the advanced amount. In the plate thickness reduction press machine, which is an intermittent process, it is inevitable that the line speed is slow compared to rolling, and the reduction in productivity becomes a big problem from the viewpoint of preventing the temperature reduction of the rolled material. It is desirable to reduce the amount and increase the advanced amount.

  Therefore, as a result of intensive studies on means for reducing the rolling load under the thickness reduction of the hot slab and increasing the advanced amount of the material, the present inventors have turned the mold during the rolling or at the dead center of the rolling. It is found that the plastic flow of the material toward the downstream side in the slab traveling direction can be increased by changing the direction of the contact area between the mold and the slab from the upstream side to the downstream side in the slab traveling direction. It was. At this time, the slab plate thickness after the reduction can be made uniform by appropriately setting the mold shape and the rotation angle.

  In addition, when the molding surface of the mold is a convex curved surface as in Patent Document 3, even if the mold is swung and reduced, the plate thickness distribution after reduction tends to be uneven as shown in FIG. Furthermore, usually, after the molding surface of the mold is worn to some extent, refinishing of the molding surface is performed by cutting or grinding, but it takes a long time to process the convex curved surface.

  As described above, the present invention has been made to solve the problems of the prior art, and reduces the reduction load when the slab is reduced in the plate thickness direction to further reduce the large pressure, reduce the hard material, reduce the size of the equipment, etc. It is an object of the present invention to provide a hot slab thickness reduction method and apparatus capable of improving the productivity by increasing the advanced amount of slab accompanying reduction.

  It is another object of the present invention to provide a hot slab sheet thickness reduction method and apparatus capable of preventing a reduction in the temperature of a rolled material by reducing the amount of backward movement of the material due to reduction and increasing the advanced amount.

  Still another object of the present invention is to provide a hot slab thickness reduction method and apparatus in which the thickness distribution after reduction does not become uneven.

  The present invention has been made based on these findings and has the following characteristics.

(1) A hot slab having an upstream compressed surface that is expanded and inclined in the direction of entry with respect to the traveling direction of the hot slab and a downstream compressed surface that is continuous with the upstream compressed surface and is expanded and inclined toward the traveling direction. A hot slab plate thickness reduction method in which a hot slab is intermittently reduced in the plate thickness direction using a pair of molds provided facing each other up and down,
The mold is squeezed in the plate thickness direction, and the slab is started to be reduced by the upstream side and the downstream side, and the mold is rotated so that the contact surface with the slab is changed to the downstream side. A method for reducing the thickness of a hot slab, wherein the mold is reduced to the bottom dead center while reducing.

(2) A hot slab having an upstream compressed surface that is expanded and inclined in the direction of entry with respect to the traveling direction of the hot slab and a downstream compressed surface that is continuous with the upstream compressed surface and is expanded and inclined toward the traveling direction. A hot slab plate thickness reduction method in which a hot slab is intermittently reduced in the plate thickness direction using a pair of molds provided facing each other up and down,
The mold is squeezed in the thickness direction, and the slab is squeezed to the bottom dead center by the upstream side squeezing surface and the downstream side squeezing surface, and then the contact surface with the slab is changed to the downstream side squeezing surface. A method for reducing the thickness of a hot slab, characterized by rotating a mold.

  (3) The rotation angle of the mold is the same as the angle formed by the slab traveling direction and the downstream pressure surface, and the mold is rotated until the downstream pressure surface is parallel to the slab traveling direction (1) Or the thickness reduction method of the hot slab as described in (2).

(4) A mold receiver having a circular contact surface with the mold, and attached to the mold rotation shaft, and having a circular contact surface with the mold receiver , facing each other vertically with a hot slab in between. A pair of molds arranged between the contact surfaces of the molds and the contact surface of the mold receiver, and a roller that can rotate the molds. A driving mechanism for rotating the shaft as an axis, and a rolling-down means for rolling down these molds in the thickness direction of the hot slab, wherein the mold is in the incoming direction with respect to the traveling direction of the hot slab. An apparatus for reducing the thickness of a hot slab, comprising: an upstream-side pressure-lower surface that is expanded and inclined; and a downstream-side pressure-lower surface that is continuous with the upstream-side pressure surface and is inclined toward the advancing direction.

  (5) A mold receiver having an arc-shaped contact surface with the mold, a mold attached to the mold rotating shaft and having an arc-shaped contact surface with the mold receiver, and a contact surface of the mold A roller that is interposed between the contact surface of the mold receiver and that allows the mold to rotate, and a drive mechanism that rotates the mold about the mold rotation axis. A mold rotation mechanism for a hot slab plate thickness reduction device.

(6) Each mold has an upstream flank that is expanded and inclined in the incoming direction with respect to the direction of travel of the hot slab, and a downstream flank that is continuous with the upstream flank and is expanded and inclined toward the advancing direction. A mold rotation mechanism for a hot slab plate thickness reduction device as described in (5).

  According to the plate thickness reduction method and apparatus of a hot slab of the present invention, the reduction load can be greatly reduced as compared with the prior art, and the advanced amount of material by reduction can be increased. As a result, a great effect can be expected in many respects, such as a further reduction of the plate thickness, a reduction of the hard material, and a compact facility itself.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In Embodiment 1 of the present invention shown in FIG. 1, as shown in FIG. 3, the mold 2 is rolled down with the upstream pressure surface 18 inclined at an angle θ and the downstream pressure surface 19 inclined by an angle φ with respect to the slab traveling direction. The slab 1 starts to be crushed from the dead center position (the position where the mold 2 is farthest from the slab 1), and the dies are moved in the downward direction to the crushed dead center position (the position where the mold 2 is most crushed from the slab 1) In addition to moving up and down, the direction of the arrow in the figure (hereinafter referred to as the forward rotation direction and the reverse rotation direction is reversed so that the contact surface of the mold 2 and the slab 1 is moved downstream in the slab traveling direction. The mold is rotated by an angle φ in the direction of movement). In the present embodiment, the contact surface between the slab 1 and the mold 2 that is being reduced is substantially only the downstream pressure surface 19.

  Further, in the second embodiment of the present invention shown in FIG. 2, as shown in FIG. 3, the mold 2 is in a state where the upstream pressure surface 18 is inclined by an angle θ and the downstream pressure surface 19 is inclined by an angle φ with respect to the slab traveling direction. The slab 1 starts to be reduced from the position of the top dead center, and the mold is moved up and down only to the position of the bottom dead center, and the contact surface between the mold 2 and the slab 1 is moved to the position of the bottom dead center. The mold is rotated by an angle φ in the forward rotation direction so as to change to the downstream side in the slab traveling direction. In the present embodiment, the contact surface between the slab 1 and the mold 2 that is being rolled up to the bottom dead center position is the both sides of the upstream side pressure surface 18 and the downstream side pressure surface 19 (however, the conventional plate thickness reduction as shown in FIG. 6). The contact length is shorter than in the case of the press device), and the contact surface becomes only the downstream pressure surface 19 by rotating the die in the forward rotation direction at the rolling dead center.

  The angle θ is not particularly limited, but is preferably 15 ° to 35 °, and particularly preferably 20 ° to 30 °. This is because if the angle θ is too small, the contact length between the mold and the material becomes long, so the load increases. If the angle θ is too large, the contact between the upstream pressure surface 18 and the material becomes unstable, and a stable press is achieved. This is because there is a problem that processing becomes difficult.

  The angle φ is not particularly limited, but is preferably 5 ° to 30 °, and particularly preferably 20 ° to 30 °. This is because if the angle φ is too small, the effect of shortening the contact length between the mold and the material is small, that is, the load reducing effect is small, and even if the angle φ is excessively large, the load reducing effect tends to be saturated. Because.

  FIG. 4 is an explanatory view showing an embodiment of a mold rotation mechanism for realizing the hot slab reduction method according to the first and second embodiments of the present invention. The mold 2 has a circular arc contact surface with the mold receiver 4, and the displacement is fixed by the mold rotation shaft 10 so as to contact the mold receiver 4 via the cylindrical roller 8. Only rotational movement is possible. Further, the mold 2 is connected to the hydraulic cylinder 11 via a rotation shaft, and performs a rotation motion about the mold rotation shaft 10 by the vertical movement of the hydraulic cylinder 11. Further, the rotation range of the mold 2 is limited by the upstream side pressure surface 18 being constrained by the mold cradle 17 in the reverse rotation direction position. At this time, although not shown in FIG. 4, the vertical movement of the mold receiver 4 in which the mold 2 is installed is reduced by the eccentric movement used in the conventional hot slab press apparatus shown in FIG. In addition to the operation, any simple vertical rolling motion may be used, and the slab feed in the slab traveling direction during the rolling motion in the thickness direction may be performed by the pinch roll 12.

  Hereinafter, the operation of the hot slab reduction method of FIGS. 1 and 2 will be described using the mold rotation mechanism of FIG.

  In the first embodiment shown in FIG. 1, the die 2 is pulled up by the hydraulic cylinder 11 at the reduction top dead center position and rotated in the reverse rotation direction by the hydraulic cylinder 11. The rotation is fixed. Starting from the top dead center position, the rolling down is started in the vertical direction, and the downstream end connecting portion of the mold 2 is pushed forward by the hydraulic cylinder 11 and rotated in the forward direction. The reduction and rotation are performed simultaneously so that the moving angle becomes φ. At this time, it is only necessary to set the mold rotation angle to be φ at the maximum stroke of the hydraulic cylinder 11, that is, the downstream pressure surface 19 to be horizontal, and the mold rotation angle according to the reduction operation position. Can be controlled. Between the passes, that is, until the upper and lower molds are separated and moved to the top dead center position, the slab 1 is fed by a predetermined feed amount by the pinch roll 12, and the hydraulic cylinder 11 downstream of the mold 2 The end connecting portion is pulled up and rotated in the reverse rotation direction, and the rotation is fixed by the mold receiving base 17. Hereinafter, the hot slab is reduced over the entire length in the longitudinal direction by continuously performing this operation.

  In the second embodiment shown in FIG. 2, the die 2 is pulled up by the hydraulic cylinder 11 at the reduction top dead center position and rotated in the reverse rotation direction by the hydraulic cylinder 11. The rotation is fixed. Starting from the top dead center position, the up-down direction is started and this state is maintained until the bottom dead center position is reached, and the downstream end connecting portion of the mold 2 is connected by the hydraulic cylinder 11 at the bottom dead center position. The die 2 is rotated by an angle φ in the forward direction while pushing out, and the reduction is completed at the downstream pressure surface 19. At this time, the rotation angle of the mold may be set to φ at the maximum stroke of the hydraulic cylinder 11. The operation between the passes, that is, the operation until the upper and lower molds are separated and moved to the top dead center position is the same as the operation in the above-described embodiment of FIG. By doing so, the hot slab is reduced over the entire length in the longitudinal direction.

  In the embodiment of the mold rotation mechanism of FIG. 4, both the operations of FIGS. 1 and 2 can be performed only by changing the control timing of the mold rotation. However, in the first embodiment shown in FIG. 1, the slab 1 is reduced only on the downstream pressure surface 19 by both the reduction operation and the mold rotation mechanism, and in the second embodiment shown in FIG. By rotating the mold, only the portion in contact with the downstream pressure surface 19 is reduced. Therefore, since the first embodiment has a shorter contact length and a smaller rolling load than the second embodiment, the entire apparatus can be miniaturized. On the contrary, in the second embodiment, the hydraulic cylinder 11 only performs the reduction associated with the mold rotation after the reduction to the reduction dead center, so that the capacity of the hydraulic cylinder 11 can be reduced compared to the first embodiment. There is a feature. These may be appropriately selected in consideration of the target slab material, the rolling load range depending on the slab size, the equipment cost, and the like.

  Note that the rotation of the mold in the present invention is not limited to using the mold rotation mechanism shown in FIG. 4, and the rotation operation may be realized by a link mechanism, for example.

  As an example, the hot slab of the above-described Embodiment 1 (Example 1) and Embodiment 2 (Example 2) is used by using the plate thickness reduction press device provided with the mold rotation mechanism shown in FIG. Plate thickness reduction was performed. As a comparative example of the rolling load and the advanced amount of material accompanying the rolling, the conventional plate thickness rolling device shown in FIG. 6 was also used. The target slab is plain steel with a plate thickness of 254 mm, a plate width of 1500 mm, and a length of 9000 mm. First, the slab was heated to 1200 ° C. in a heating furnace, extracted from the heating furnace, conveyed to a sheet thickness reduction press device by a conveyance table, and reduction in the sheet thickness direction was started. At this time, the temperature of the slab at the start of the reduction was about 1100 ° C., and the reduction was performed to a plate thickness of 38 mm (reduction rate of about 85%). The shape of the mold shown in FIG. 3 was used, but the inclination angle θ of the upstream flank was fixed at 20 °, and the inclination angle φ of the downstream flank was changed in the range of 0 to 20 °. At this time, the mold rotation angle is the same as the inclination angle φ of the downstream pressure surface. That is, under the condition that the inclination angle φ of the downstream side pressure surface is 0 °, the same reduction condition as that of the conventional plate thickness reduction apparatus shown in FIG. 6 is obtained.

  FIG. 5 is a diagram showing a change in the maximum reduction load when the inclination angle φ of the downstream pressure surface is 0 to 20 °, and the reduction load in the comparative example is arranged as 1.0. The maximum reduction load is the maximum value of the reduction load from the start of reduction to the end of reduction. In Example 1 of the present invention, since the reduction is performed only on the downstream side pressure surface, the maximum reduction load is constant regardless of the inclination angle φ of the downstream side pressure surface, and there is an approximately 45% load reduction effect compared to the comparative example. It was. Further, in Example 2 of the present invention, the maximum reduction load greatly depends on the inclination angle φ of the downstream pressure surface, about 30% of the load reduction effect at φ = 10 °, and about φ20 °. There was a load reduction effect of 40%. Further, when the relationship between the advanced amount of the slab and the reverse amount due to the reduction was investigated, the ratio of the advanced amount and the reverse amount was about 0.5: 0.5 in the conventional sheet thickness reduction device, whereas the present invention In Example 1 and Example 2, it was confirmed that the advanced amount increased from 0.6: 0.4 to 0.7: 0.3.

Explanatory drawing which shows one Embodiment (Embodiment 1) of the board thickness reduction method of this invention. Explanatory drawing which shows one Embodiment (Embodiment 2) of the board thickness reduction method of this invention. Explanatory drawing which shows an example of the metal mold | die shape provided for implementation of this invention. Explanatory drawing which shows an example of the metal mold | die rotation mechanism with which implementation of this invention is provided. Explanatory drawing which shows the Example of the reduction effect of the rolling load at the time of hot slab board thickness reduction by this invention. The block diagram of the conventional hot slab press apparatus. The block diagram of the conventional plate | board thickness reduction apparatus. The schematic diagram of the plate thickness unevenness | corrugation which generate | occur | produces under the plate | board thickness pressure by a metal mold | die with a convex-surface shape.

Explanation of symbols

  2 ... Mold, 3 ... Slider, 4 ... Mold receiver, 5 ... Main body, 6 ... Circular hole, 7 ... Crank, 8 ... Cylindrical roller, 9 ... Frame, 10 ... Mold rotating shaft, 11 ... Hydraulic cylinder, DESCRIPTION OF SYMBOLS 12 ... Pinch roll, 13 ... Table roller, 14 ... Rod, 15 ... Mold back-and-forth movement mechanism, 16 ... Housing, 17 ... Mold rotation receiving stand, 18 ... Upstream pressure side, 19 ... Downstream pressure side

Claims (6)

The upstream slab has an upstream flank that is expanded and inclined in the ingress direction with respect to the traveling direction of the hot slab, and a downstream flank that is continuous with the upstream flank and is inclined to expand in the advancing direction. A hot slab plate thickness reduction method in which a hot slab is intermittently reduced in the plate thickness direction using a pair of molds provided opposite to each other,
The mold is squeezed in the plate thickness direction, and the slab is started to be reduced by the upstream side and the downstream side, and the mold is rotated so that the contact surface with the slab is changed to the downstream side. A method for reducing the thickness of a hot slab, wherein the mold is reduced to the bottom dead center while reducing. The upstream slab has an upstream flank that is expanded and inclined in the ingress direction with respect to the traveling direction of the hot slab, and a downstream flank that is continuous with the upstream flank and is inclined to expand in the advancing direction. A hot slab plate thickness reduction method in which a hot slab is intermittently reduced in the plate thickness direction using a pair of molds provided opposite to each other,
The mold is squeezed in the thickness direction, and the slab is squeezed to the bottom dead center by the upstream side squeezing surface and the downstream side squeezing surface, and then the contact surface with the slab is changed to the downstream side squeezing surface. A method for reducing the thickness of a hot slab, characterized by rotating a mold. The rotation angle of the mold is the same as the angle formed by the slab traveling direction and the downstream crushed surface, and the mold is rotated until the downstream crushed surface is parallel to the slab traveling direction. 2. A method for reducing the thickness of a hot slab according to 2. A mold receiver with a circular contact surface with the mold, and attached to the mold rotation shaft, with the contact surface with the mold receiver in an arc shape, placed facing the top and bottom across the hot slab A pair of molds, a roller interposed between a contact surface of the molds and a contact surface of the mold receiver, and the molds being rotatable, and the molds with the mold rotation axis as an axis. A driving mechanism for rotating the slab and a reduction means for squeezing these dies in the thickness direction of the hot slab. An apparatus for reducing the thickness of a hot slab, comprising: an upstream compressed surface and a downstream compressed surface that is continuous with the upstream compressed surface and is inclined toward the advancing direction. A mold receiver having an arc-shaped contact surface with the mold, a mold attached to the mold rotating shaft and having an arc-shaped contact surface with the mold receiver, and the mold contact surface and the mold receiver And a driving mechanism for rotating the mold about the mold rotation axis. Mold rotation mechanism for inter-slab plate thickness reduction device. Each mold has an upstream side pressure surface that is expanded and inclined in the direction of entry with respect to the direction of travel of the hot slab, and a downstream side pressure surface that is continuous with the upstream side pressure surface and is expanded and inclined toward the direction of travel. A mold rotation mechanism for a hot slab plate thickness reduction device according to claim 5.

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