JP5141009B2 - Mold for width reduction of hot slabs - Google Patents

Description

  The present invention relates to a mold for reducing the width of a hot slab that can stably reduce the width of the hot slab while the width of the hot slab is reduced by a plate width press device.

  As a means for changing the width of the hot slab, the temperature of the slab manufactured by the continuous casting process is not lowered, or after the temperature is once lowered, the slab is heated to a predetermined temperature in a heating furnace. 2. Description of the Related Art A plate width press apparatus that uses a pair of dies installed so as to face each other in the plate width direction of the hot slab to intermittently reduce the hot slab in the plate width direction is used. In the width reduction by this board width press apparatus, the width reduction of about 300-350mm at the maximum is normally performed with respect to the hot slab of the width of about 900-2000mm, and the slab cast to the same width by continuous casting. This makes it possible to manufacture steel plate products with different widths. This has greatly contributed to the productivity improvement and rationalization of the steel sheet manufacturing process, such as reducing the number of width changes in the continuous casting process, expanding schedule-free rolling in the hot rolling process, and increasing the coil weight. The merit increases as the width reduction capability of the plate width press device increases.

In general, the width reduction load F by the plate width pressing device can be approximately obtained by the equation (2).

k is the deformation resistance of the material, Q _p is the rolling force function, h is the slab thickness, and L ₀ is the contact length between the slab and the mold. Increasing the width reduction amount increases the contact length L _0, so the conventional width press method cannot avoid increasing the width press load such as the width reduction load and the width reduction torque, and the power of the reduction motor, flywheel, etc. It is necessary to reinforce the rigidity of devices such as systems, drive systems that transmit power, and housings. From the above formula (2), in order to solve the problem of increasing the width reduction load, for example, the feed pitch P (slab transport distance for each pass of the press) is shortened (usually about 350 to 400 mm), or the die It is effective to shorten the contact length L ₀ by increasing the tilt angle. In addition, increasing the width reduction amount also promotes troubles such as buckling and slipping of the slab, so the conventional width reduction mold and width pressing method cannot increase the width reduction amount of the hot slab so much. There was a point. FIG. 10 shows the force in the contact start state between the mold and the slab when the width is reduced by a conventional width reduction mold (hereinafter referred to as a flat mold) having a parallel portion and one inclined portion. In the reduction pass, the contact starts from the mold inclined portion and the slab inclined surface that is reduced by the mold inclined portion in the front pass. At this time, the conditions for preventing the occurrence of slip in the longitudinal direction are as follows. When the inclination angle of the mold is α, the friction coefficient between the mold and the slab is μ, and the contact force at the start of contact is F ₀ , the following (3) It is represented by the formula (3) ′.

  Normally, under the width reduction by the plate width press apparatus, the angle of the inclined portion is about 12 °, and the friction coefficient must be 0.21 or more in order to satisfy the relationship (2) ′. Further, in order to prevent the slab from being twisted not only in the longitudinal direction but also in the thickness direction, a technique has been proposed in which the friction surface of the mold is roughened to adjust the friction coefficient to 0.3 or more (for example, a patent). Reference 1).

In addition to this, a method for preventing slipping during significant reduction by setting the feed pitch and the inclination angle of the mold has also been proposed (for example, see Patent Document 2). Patent Document 2 is characterized in that the feed pitch or the inclination angle α of the mold is set so as to satisfy the following expression (4).

ΔW is a width reduction amount (mm) by a mold on one side. Normally, when the width is reduced by the plate width press apparatus, the angle of the inclined portion is about 12 °. For example, when the width reduction amount is 300 mm, the feed pitch P is 706 mm or more in the setting according to the above equation (4). Since the mold parallel part starts to contact the unpressed lower part on the side surface of the slab, no slip occurs at the start of width reduction. Moreover, in patent document 2, the 2nd parallel part is formed in a metal mold | die inclination part, and the part pressed down in this 2nd parallel part by the front pass and the parallel part of a metal mold | die lower surface contact in the said path | pass. A method is disclosed in which slippage at the time of width reduction is prevented by setting a mold shape and a feed pitch so as to start.

  However, each of the prior arts described above has the following problems.

  First, as a measure for reducing the width reduction load at the time of significant reduction estimated from the above formula (2), in the method of reducing the contact length between the slab and the mold by shortening the feed pitch P, the slab tip Since the time required for width reduction from the tip to the tail increases, productivity is lowered and the temperature of the slab is lowered, so that a desired finishing temperature in hot rolling cannot be secured. Moreover, in the method of reducing the contact length between the slab and the mold by increasing the mold inclination angle, the slip at the start of contact between the mold and the slab is promoted and stabilized by the relationship of the above formula (3) ′. There is a problem in that it is difficult to reduce the width of the paper.

  In the method of roughening the die pressing surface disclosed in Patent Document 1 and increasing the coefficient of friction to enable significant reduction, the die pressing surface that accompanies the pressing may be used immediately after the die is replaced. It is difficult to control the change in properties, and in order to keep the coefficient of friction constantly high, it is necessary to change the mold frequently. Due to a decrease in productivity and frequent finish processing of the mold pressure lower surface There was a problem that the mold life was shortened.

The method of setting the feed pitch P or the mold inclination angle α disclosed in Patent Document 2 (4) has various problems even if slippage during drastic reduction can be prevented. First, when adjusting the feed pitch based on the formula (4), for example, if the mold inclination angle α is 12 ° and the width reduction amount W is 300 mm, the feed pitch P must be 706 mm or more, and is usually 350 to 400 mm. Therefore, it is inevitable that the width reduction load will increase significantly. When the mold inclination angle α is adjusted by the equation (4), for example, when the width reduction amount W is 300 mm and the feed pitch P is 400 mm, the mold inclination angle α needs to be 20.6 ° or more. Become. However, when the mold inclination angle increases, the dogbone formed at the end of the slab due to the width reduction becomes excessive, and the width return due to the subsequent horizontal rolling increases. That is, since the width reduction efficiency η defined by the following equation (5) deteriorates, it is necessary to set a large amount of width reduction necessary to obtain a desired product width, which causes an increase in width reduction load. There was a problem.

W ₀ is the slab width, W ₁ is the slab width after the width reduction by the sheet width press, and W ₂ is the slab width after one-pass horizontal rolling from the state of W ₁ to the slab thickness before the width reduction. Further, when the dogbone becomes excessive, the number of subsequent horizontal rolling passes must be increased, resulting in a decrease in productivity and a decrease in slab temperature.

  In addition, a second parallel part is formed in the mold inclined part disclosed in Patent Document 2, and in this pass, the part parallel to the second parallel part and the mold parallel part are reduced in the previous pass. In the method of setting the mold shape and the feed pitch so as to start contact, the occurrence of slip can be avoided as a basic idea, but when performing a large width reduction, the reduction stroke amount, mold separation and Due to the relationship between the slab feed start timing and the like, there is a problem that the mold and the slab collide, and the width reduction amount has to be regulated within a range in which this collision can be avoided.

FIG. 4 is a diagram showing an example of a form at the time of width reduction by the mold having the shape shown in Patent Document 2, and the mold is parallel to the side surface of the hot slab on the pressing surface of the hot slab in the traveling direction. An intermediate slope that has a parallel mold part (hereinafter referred to as a mold lower surface parallel part) and that extends continuously at an angle α ₁ toward the inward direction of the hot slab in the direction parallel to the mold lower surface parallel part. An intermediate parallel portion substantially parallel to the side surface of the hot slab continuously to the intermediate inclined portion, and a hot slab traveling direction incoming direction of the intermediate parallel portion in a hot slab advancing direction inward direction It has an entrance-side inclined portion that widens at an angle α ₂ . In FIG. 4, the intersection of the mold lower surface parallel part and the intermediate inclined part is point A, the intersection of the intermediate inclined part and the mold intermediate parallel part is B point, and the intersection of the mold intermediate parallel part and the entry side inclined part Is the point C, and the end point at which the inclining portion comes into contact with the slab at the rolling dead center is D. In addition, points A ′ to D ′ are points that come into contact with points A to D, respectively, at the bottom dead center. Hereinafter, the mold having the shape shown in FIG. 4 is referred to as a two-stage mold.

Next, a guideline for determining the two-stage mold shape of FIG. 4 will be described. In the present invention, the object is to prevent the mold and slab from slipping, and in this pass, the mold lower surface parallel part starts contact with the part that was pressed down by the mold middle parallel part in the previous pass. Based on. For this purpose, the intermediate inclination angle α ₁ , the reduction amount w ₁ at the intermediate inclination portion, and the feed pitch P must satisfy the following expression (6).

L is the contact length in the pass between the parallel part on the lower surface of the mold and the part pressed down by the intermediate parallel part of the mold in the previous pass, and is hereinafter referred to as the parallel part contact length.

Moreover, the width reduction load at the time of plate width reduction is substantially proportional to the contact length of a metal mold | die and a slab in the reduction dead center shown by following (7) Formula.

w ₂ is a reduction amount to be reduced by the second inclined portion, and Δf is a length obtained by subtracting the parallel portion contact length L ₀ from the intermediate parallel portion length L. From the viewpoint of equipment protection, it is important not to excessively increase the width reduction load. For example, the contact length L ₀ calculated by the above formula (7) is the maximum width reduction in the conventional width reduction results. What is necessary is just to determine a metal mold | die shape so that it may become equivalent to the contact length at the time, and the relationship of (6) Formula may be satisfy | filled. At this time, it is advantageous to make the contact length L of the parallel part in the equation (6) long from the viewpoint of slip prevention, but when the feed pitch P is determined by the structure and specifications of the mechanical device. For this, it is necessary to increase the inclination angle α ₁ of the intermediate inclined portion or to reduce the reduction amount w ₁ of the intermediate inclined portion. In addition, the sum of the intermediate inclined part w ₁ and the entry side inclined part w ₂ is half of the total width reduction amount, but it is reduced from the part that was reduced by the mold intermediate parallel part in the previous pass under all width reduction conditions. In order to start, it is necessary to satisfy the relationship of the following formula (8).

If the above equation (8) is not satisfied, the contact starts from the middle parallel part of the mold and the side surface of the slab in this pass, but in this case, the mold and the slab also start contact from each parallel part. Therefore, it is possible to prevent slippage. For example, if the total width reduction amount is 350 mm, w ₁ must be 87.5 mm or more in order to satisfy the above equation (8). In addition, w ₁ must be smaller than the reduction stroke S. In this case, the range of w ₁ is determined from these restrictions. Similarly, when the total width reduction amount is 350 mm and equation (8) is not satisfied, that is, when w ₁ is 87.5 mm or less and w ₂ is 87.5 mm or more, w ₂ must be smaller than the reduction stroke S. In this case, the range of w ₂ is determined from these constraints.

Next, conditions for causing a collision between the mold and the slab between the reduction passes will be described. Between the reduction passes, the mold is separated by a distance of the reduction stroke S determined by the mechanical device structure, and the slab is conveyed by a predetermined feed pitch P in the traveling direction. Normally, since the rolling cycle of the width rolling press device is around 50 times per minute, one cycle t0 of the rolling pass operation is about 1.2 seconds. If the time from when the mold starts separating from the rolling dead center until reaching the top dead center is defined as the time between the rolling passes, the time tp between the rolling passes is about 0.6 seconds, which is half of one cycle. FIG. 5 is a schematic diagram showing an example of the timing of slab conveyance between the mold separation and the reduction pass. After the mold starts to separate from the slab, the slab conveyance is started after a slight time delay td. In the next pass, the sheet is fed by the distance of the feed pitch P until the operation of the mold in the pressing direction is started. In addition, conveyance of the slab between passes is implemented by the pinch roll and conveyance roll installed before and behind the mold. The slab transfer start delay time td is normally about 0.1 to 0.2 sec. However, considering the case where the slab transfer start delay time td is shortened to the limit, the angle α ₁ formed by the lower parallel part of the mold and the first inclined part of the mold. Is larger than the angle φ ₀ formed by the vector of the feed pitch P and the stroke S calculated by the following equation (9) (hereinafter referred to as vector A) and the hot slab travel direction, the die is placed between the reduction passes. And slab may collide.

FIG. 6 shows the mold and slab between the rolling passes when the angle α ₁ formed by the parallel part on the lower surface of the mold and the intermediate inclined part of the mold is larger than the angle φ ₀ formed by the traveling direction of the vector A and the hot slab. In this example, the slab collides with the vicinity of the intersection of the mold parallel part on the exit side in the traveling direction of the hot slab and the first inclined part of the mold. FIG. 7 shows an example in which the angle α ₂ formed by the mold intermediate parallel part and the entry side inclined part is larger than the angle φ ₀ formed by the vector A and the traveling direction of the hot slab. A collision of the slab with the vicinity of the intersection of the intermediate parallel part and the entry side inclined part occurs. By making the slab conveyance start delay time td as long as possible, that is, by starting the conveyance of the slab after the mold is separated from the slab to some extent, the collision between the slab and the mold shown in FIGS. 6 and 7 can be avoided. However, in order to quickly transport a slab having a weight of 20 to 30 tons, a large amount of power is required and the load on the drive system is greatly increased, so the slab transport start delay time td is made too long. The fact is that you can't.
JP-A-5-15908, claims, drawings, etc. JP-A-9-253780, claims, drawings, etc.

  The present invention has been made in view of the above-described circumstances, and in the width reduction of the hot slab by the plate width press device, it prevents slipping during the reduction and avoids the collision between the slab and the mold and stably. The present invention relates to a die for width reduction of a hot slab that enables width reduction.

  In order to solve the above-mentioned problem, the present inventors diligently studied a measure for avoiding the collision between the mold and the slab between the rolling passes, and in the above-described two-stage mold, the intermediate inclined part or the entrance-side inclined part is provided. Inspired to be multistage.

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

但し、
Ｓ：圧下ストローク（ｍｍ）
Ｐ：送りピッチ（ｍｍ）
ｔｄ：スラブ搬送開始遅れ時間（ｓｅｃ．）
ｔｐ：金型が圧下死点から離反を開始して上死点に達するまでの時間；圧下パス間時間（ｓｅｃ．） 1st invention is the metal mold | die for width reduction which rolls down the hot slab installed relatively opposite to the board width direction of a hot slab intermittently to the board width direction, and the advancing direction exit side of a hot slab A parallel mold part parallel to the side surface of the hot slab, an intermediate inclined part extending continuously in the direction of entry of the hot slab toward the entrance side of the hot slab, and the intermediate inclined part An intermediate parallel part that is continuously substantially parallel to the side surface of the hot slab, and an inlet side slope that continuously extends to the incoming side end of the hot slab in the direction of hot slab advancement toward the incoming side of the hot slab. And
The intermediate inclined portion includes a second inclined portion that is continuous with the mold parallel portion and extends at an angle α1 toward the inward direction of the hot slab, and the hot slab of the second inclined portion advances. A first inclined portion that extends continuously at an angle φ at the direction-entrance end, and the angle φ of the first inclined portion <the angle α1 of the second inclined portion,
An angle φ of the first inclined portion is a value expressed by the following expression (1), a hot slab width reduction die.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.)

The second invention is a width reduction mold for intermittently reducing the hot slab installed in the plate width direction relative to the plate width direction of the hot slab. A parallel mold part parallel to the side surface of the hot slab, an intermediate inclined part extending continuously in the direction of entry of the hot slab toward the entrance side of the hot slab, and the intermediate inclined part An intermediate parallel part that is continuously substantially parallel to the side surface of the hot slab, and an inlet side slope that continuously extends to the incoming side end of the hot slab in the direction of hot slab advancement toward the incoming side of the hot slab. And
The intermediate inclined portion includes a first inclined portion that is continuous with the mold parallel portion and spreads at an angle φ toward the inward direction of the hot slab, and the hot slab of the first inclined portion advances. A second inclined portion that extends continuously at the angle α1 at the direction-entrance end, and the angle φ of the first inclined portion is less than the angle α1 of the second inclined portion,
An angle φ of the first inclined portion is a value represented by the above formula (1), a hot slab width reduction die.

3rd invention is the metal mold | die for width reduction which rolls down the hot slab installed relatively opposite to the board width direction of a hot slab intermittently to a board width direction, and the advancing direction exit side of a hot slab A parallel mold part parallel to the side surface of the hot slab, an intermediate inclined part extending continuously in the direction of entry of the hot slab toward the entrance side of the hot slab, and the intermediate inclined part An intermediate parallel part that is continuously substantially parallel to the side surface of the hot slab, and an inlet side slope that continuously extends to the incoming side end of the hot slab in the direction of hot slab advancement toward the incoming side of the hot slab. And
The inlet side inclined portion includes a first inclined portion that extends continuously at an angle φ toward an inlet side direction of the hot slab in the hot slab traveling direction at the inlet side end of the intermediate parallel portion; And a third inclined portion that extends continuously at an angle α2 at the end of the hot slab in the direction of travel of the hot slab, and the angle φ of the first inclined portion <the angle α2 of the third inclined portion Yes,
An angle φ of the first inclined portion is a value represented by the above formula (1), a hot slab width reduction die.

4th invention is the 1st-3rd invention WHEREIN: The two-stage metal mold | die for width reduction which squeezes the hot slab installed in the plate width direction intermittently in the plate width direction of the hot slab This is a two-stage die for width reduction of a hot slab.
5th invention is the width reduction method of the hot slab using the mold for width reduction of the hot slab of any one of Claims 1-4, Comprising: The conditions which satisfy | fill said Formula (1) This is a method of reducing the width of the hot slab.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.)

  As described above, by using the hot slab width reduction die according to the present invention, during the hot slab width reduction by the plate width press apparatus, slippage at the time of reduction is prevented and collision between the slab and the die is avoided. And stable width reduction is possible.

  1 to 3 are embodiments showing different shapes of the width reduction mold according to the present invention.

  FIG. 1 corresponds to the width reduction mold according to the first invention in which the above-described two-stage mold is improved, and shows a state at the top dead center when the width of the hot slab is reduced by the width reduction mold. Indicates. The improvement with respect to the two-stage mold is that two different inclined surfaces are formed in the intermediate inclined portion 20, and the inclination angle of the first inclined portion 22 continuous to the mold lower surface parallel portion 10 is φ, the first inclination. The inclination angle of the second inclined part 24 that is continuous with the part, that is, the intermediate parallel part side is α1. Here, the height of the region of φ <α1 and the inclination angle φ is h1. The method of determining numerical values such as α1, α2, w1, w2, and P is the same as in the case of the two-stage mold in FIG.

FIG. 2 corresponds to the width reduction mold according to the first invention in which the above-described two-stage mold is improved, and shows the state at the top dead center when the width of the hot slab is reduced by the width reduction mold. Indicates. The improvement with respect to the two-stage mold is that two different inclined surfaces are formed in the intermediate inclined portion 20, and the inclination angle of the second inclined portion 24 continuing to the mold lower surface parallel portion 10 is α1, the second The first inclined portion 22 that is continuous with the inclined portion, that is, the inclination angle on the intermediate parallel portion side is φ. Here, φ <α1, the height of the region of the inclination angle phi is Ru h1 der. The method of determining numerical values such as α1, α2, w1, w2, and P is the same as in the case of FIG.

  In the following, the form of the width reduction mold of FIGS. 1 and 2 will be described individually with reference to supplementary explanatory diagrams.

FIG. 8 shows a condition in which a collision occurs between the intersection A of the mold parallel part on the exit side of the hot slab and the intermediate inclined part of the mold and the vicinity of the slab B ′ as shown in FIG. It is a figure which shows the relative position of a metal mold | die and a slab in the case of moving a metal mold | die and a slab along the timing of the mold separation shown in FIG. 5, and the conveyance of the slab between the reduction paths. Incidentally, w _1, w ₂ are each intermediate inclined portion, a rolling reduction in the entry-side inclined portion, L _1, L ₂ are each intermediate inclined portion, a contact length between the inlet side inclined section and the slab. The mold is separated by Sd during the slab conveyance start delay time td. When the slab conveyance is started from this state and conveyed to the feed pitch P, the mold A point is a dotted line relative to the slab. Move the locus indicated by. In this case, the hatched area in the vicinity of the slab B ′ point is the area that collides with the mold.

  In the first invention, in order to avoid this collision, the shape of the mold is changed as shown in FIG.

  The angle φ of the first inclined portion may be the inclination of the broken line in FIG. 8 and can be calculated by the above equation (1).

In FIG. 8, the conditions for the collision between the mold and the slab are expressed by the following equation (10).

The value on the left side of equation (10) corresponds to the height h ₁ ′ of the collision area in FIG. Further, from the viewpoint of avoiding collision prevention, the length of the first inclined portion having the angle φ is preferably increased within a range not satisfying the expression (10), but the slab feed pitch in the actual operation. It may be determined in consideration of accuracy.

  FIG. 2 shows a width reduction mold corresponding to the second invention. In the embodiment of FIG. 2 as well, the angle φ of the first inclined portion may be determined by the equation (1), and the length of the second inclined portion is an actual operation within a range not satisfying the equation (10). It may be determined in consideration of the accuracy of the slab feed pitch.

  Next, the mold for width reduction of FIG. 3 corresponds to the third aspect of the invention, and an improvement over the two-stage mold is that two different inclined surfaces are formed on the entry side inclined portion 40, of which the intermediate parallel portion The inclination angle of the first inclined portion 42 continuing to 30 is φ, and the subsequent inclined angle of the third inclined portion 44 is α2. Here, the height of the region of φ <α2 and the inclination angle φ is h2. Here, the height of the region of φ <α1 and the inclination angle φ is h1. The method of determining numerical values such as α1, α2, w1, w2, and P is the same as in FIG.

FIG. 9 shows a condition in which the collision between the intersection C between the mold parallel part on the exit side of the hot slab and the second inclined part of the mold and the slab D ′ occurs as shown in FIG. FIG. 6 is a diagram showing a relative position between the mold and the slab when the mold and the slab are moved along the timing of the mold separation and the conveyance of the slab between the reduction paths shown in FIG. 5. Incidentally, w _1, w ₂ are each intermediate inclined portion, a rolling reduction in the entry-side inclined portion, L _1, L ₂ are each intermediate inclined portion, a contact length between the inlet side inclined section and the slab. The mold is separated by Sd during the slab conveyance start delay time td, and when the slab conveyance is started from that state and conveyed to the feed pitch P, the mold C point is presented to the slab and is assumed to be a dotted line. Move the locus indicated by. In this case, the hatched area in the vicinity of the slab D ′ point is the area that collides with the mold. In order to avoid this collision, it is possible to change the shape of the mold as shown in FIG.

In the embodiment of FIG. 3, the angle φ may be determined by the equation (1). In FIG. 9, the condition for causing the collision between the mold and the slab is expressed by the following equation (11).

Note that the value on the left side of the equation (11) corresponds to the height h ₂ ′ of the collision area in FIG. The length of the entrance side inclined portion may be determined in consideration of the feed pitch accuracy of the slab in the actual operation within a range not satisfying the expression (11).

  Further, depending on the width reduction condition, the equations (10) and (11) may not be satisfied at the same time, and a collision between the mold and the slab may occur at two locations. It is also possible to combine the mold shapes shown in the third invention and combine them. That is, the intermediate inclined portion 20 has a first inclined portion 22 having an angle φ and a second inclined portion 24 having an angle α1, and the entry-side inclined portion 40 has a first inclined portion 42 having an angle φ and a second inclined portion having an angle α2. A mold shape having three inclined portions 44, or an intermediate inclined portion 20 has a second inclined portion 24 having an angle α1 and a first inclined portion 22 having an angle φ, and an entrance inclined portion 40 is It is possible to form a mold having a first inclined portion 42 having an angle φ and a third inclined portion 44 having an angle α2.

  Examples of the present invention will be described below. Using a sheet width press apparatus, sheet width reduction was performed on a normal steel slab having a thickness of 235 mm, a width of 1500 mm, and a heating temperature of 1200 ° C. under the conditions of (a) to (f) at a width reduction cycle of 50 times per minute. In the examples using the width reduction mold according to the present invention in (c) to (f), the feed pitch P is fixed to 400 mm, and the contact length between the slab and the mold on the basis of the condition (b). And the mold shape was determined from the relationship of the other formulas (6) to (8).

(A) Example 1 shows the case where the width reduction was performed under the conditions of the total width reduction amount = 300 mm and the feed pitch P = 400 mm in the mold shape shown in FIG. 4, and the equations (6) to (8) In order to satisfy the relationship, α ₁ = 15 °, α ₂ = 15 °, w ₁ = 90 mm, and w ₂ = 60 mm.

(B) Example 2 is a mold shape shown in FIG. 4 and the width reduction amount is 350 mm (the width reduction amount of 300 mm in Example 1 is increased to 350 mm), and the width reduction is performed under the condition of feed pitch P = 400 mm. In this case, α ₁ = 15 °, α ₂ = 15 °, w ₁ = 90 mm, and w ₂ = 85 mm so as to satisfy the relationships of equations (6) to (8).

(C) Example 3 shows a case where width reduction was performed under the conditions (same conditions as in Example 2) of the total width reduction amount = 350 mm and the feed pitch P = 400 mm in the mold shape shown in FIG. Α ₁ = 15 °, α ₂ = 15 so that the length is the same as the contact length L ₀ (= 1223 mm) between the mold and the slab in Example 2 and satisfies the relationship of the expressions (6) to (8). °, w ₁ = 90 mm, w ₂ = 85 mm. Further, φ = 11.8 ° and the height h ₁ of the first inclined portion is 5 mm.

(D) Example 4 shows a case where width reduction is performed under the conditions (the same conditions as in Example 2) of the total width reduction amount = 350 mm and the feed pitch P = 400 mm in the mold shape shown in FIG. Α ₁ = 15 °, α ₂ = 15 so that the length is the same as the contact length L ₀ (= 1223 mm) between the mold and the slab in Example 2 and satisfies the relationship of the expressions (6) to (8). °, w ₁ = 90 mm, w ₂ = 85 mm. Further, φ = 11.8 ° and the height of the second inclined portion h ₁ = 5 mm.

(E) Example 5 shows a case where width reduction is performed under the conditions (the same conditions as in Example 2) of the total width reduction amount = 350 mm and the feed pitch P = 400 mm in the mold shape shown in FIG. Α ₁ = 15 ° and α ₂ = 15 so that the contact length L ₀ (= 1223 mm) of the mold and the slab in 2 and the contact length are the same and satisfy the relationship of the expressions (6) to (8). °, w ₁ = 85 mm, w ₂ = 90 mm. Further, φ = 11.8 ° and h ₂ = 5 mm.

(F) Example 6 is a mold shape in which the mold shape shown in FIG. 1 and the mold shape shown in FIG. 3 are combined, and the conditions (full width reduction amount = 350 mm, feed pitch P = 400 mm) The same condition) shows the case of width reduction, the contact length L ₀ (= 1223 mm) of the mold and the slab in Example 2 is the same as the contact length, and the relationship of equations (6) to (8) In order to satisfy, α ₁ = 15 °, α ₂ = 15 °, and w ₁ = w ₂ = 87.5 mm. Further, φ = 11.8 ° and h ₁ = h ₂ = 5 mm. The mold shape shown in FIG. 1 and the mold shape obtained by combining the mold shapes shown in FIG. 3 are a first inclined portion 22 having an intermediate inclined portion 20 having an angle φ and a second inclined portion 24 having an angle α1. And the entry side inclined portion 40 has a first inclined portion 42 having an angle φ and a third inclined portion 44 having an angle α2.

Table 1 shows the presence / absence of collision between the die and the slab between the reduction passes under the width reduction under the above conditions (a) to (f). Although Example 1 and Example 2 have the same mold shape, when the width reduction amount increased in this conventional mold shape (Example 1 → Example 2), a collision between the mold and the slab occurred. On the other hand, Examples 3 to 6 are mold shapes having inclined portions based on the first to third inventions, respectively, and the heights h ₁ and h ₂ are appropriately set. Even under the condition (b) where the collision between the die and the slab occurred between the rolling passes (full width reduction amount, feed pitch), the die and the slab did not collide between the rolling passes.

The figure which shows the metal mold | die shape by Claim 1 of this invention. The figure which shows the metal mold | die shape by Claim 2 of this invention. The figure which shows the metal mold | die shape by Claim 3 of this invention. The figure which shows the two-stage metal mold | die shape of patent document 2. FIG. The figure which shows the separation | separation operation | movement of a metal mold | die and the conveyance operation | movement of a slab between reduction paths. The figure which the intermediate | middle inclination part collides with a slab between the reduction passes by the width reduction by the conventional two-stage metal mold | die. The figure which the entrance side inclination part collides with a slab between the reduction paths in the width reduction by the conventional two-stage metal mold | die. The figure which shows the relative position of a metal mold | die and a slab in case the intermediate | middle inclination part collides with a slab between the reduction paths in the width reduction by the conventional two-stage metal mold | die. The figure which shows the relative position of a metal mold | die and a slab in case the entrance side inclination part collides with a slab between width reduction paths by the width reduction by the conventional two-stage metal mold | die. The figure which shows the condition in the rolling dead center in the conventional flat metal mold | die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mold lower surface parallel part 20 ... Middle inclination part 22, 42 ... 1st inclination part (inclination angle (phi))
24 ... 2nd inclination part (inclination angle α1)
30 ... Intermediate parallel part 40 ... Entry side inclined part 44 ... Third inclined part (inclination angle α2)

Claims (5)

This is a die for width reduction that intermittently reduces the hot slab installed in the plate width direction relative to the plate width direction of the hot slab. A mold parallel part parallel to the side surface of the intermediate slab, an intermediate inclined part that extends continuously in the direction of entry of the hot slab in the direction parallel to the mold parallel part, and a hot slab continuous to the intermediate inclined part An intermediate parallel part that is substantially parallel to the side surface of the intermediate slab, and an inlet side inclined part that extends continuously in the hot slab traveling direction input side end of the intermediate parallel part toward the incoming direction of the hot slab traveling direction,
The intermediate inclined portion includes a second inclined portion that is continuous with the mold parallel portion and extends at an angle α1 toward the inward direction of the hot slab, and the hot slab of the second inclined portion advances. A first inclined portion that extends continuously at an angle φ at the direction-entrance end, and the angle φ of the first inclined portion <the angle α1 of the second inclined portion,
An angle φ of the first inclined portion is a value expressed by the following expression (1), a hot slab width reduction die.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.) This is a die for width reduction that intermittently reduces the hot slab installed in the plate width direction relative to the plate width direction of the hot slab. A mold parallel part parallel to the side surface of the intermediate slab, an intermediate inclined part that extends continuously in the direction of entry of the hot slab in the direction parallel to the mold parallel part, and a hot slab continuous to the intermediate inclined part An intermediate parallel part that is substantially parallel to the side surface of the intermediate slab, and an inlet side inclined part that extends continuously in the hot slab traveling direction input side end of the intermediate parallel part toward the incoming direction of the hot slab traveling direction,
The intermediate inclined portion includes a first inclined portion that is continuous with the mold parallel portion and spreads at an angle φ toward the inward direction of the hot slab, and the hot slab of the first inclined portion advances. A second inclined portion that extends continuously at the angle α1 at the direction-entrance end, and the angle φ of the first inclined portion is less than the angle α1 of the second inclined portion,
An angle φ of the first inclined portion is a value expressed by the following expression (1), a hot slab width reduction die.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.) This is a die for width reduction that intermittently reduces the hot slab installed in the plate width direction relative to the plate width direction of the hot slab. A mold parallel part parallel to the side surface of the intermediate slab, an intermediate inclined part that extends continuously in the direction of entry of the hot slab in the direction parallel to the mold parallel part, and a hot slab continuous to the intermediate inclined part An intermediate parallel part that is substantially parallel to the side surface of the intermediate slab, and an inlet side inclined part that extends continuously in the hot slab traveling direction input side end of the intermediate parallel part toward the incoming direction of the hot slab traveling direction,
The inlet side inclined portion includes a first inclined portion that extends continuously at an angle φ toward an inlet side direction of the hot slab in the hot slab traveling direction at the inlet side end of the intermediate parallel portion; And a third inclined portion that extends continuously at an angle α2 at the end of the hot slab in the direction of travel of the hot slab, and the angle φ of the first inclined portion <the angle α2 of the third inclined portion Yes,
An angle φ of the first inclined portion is a value expressed by the following expression (1), a hot slab width reduction die.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.) The two-stage mold for width reduction which is a two-stage die for width reduction that intermittently reduces the hot slab installed in the plate width direction relative to the plate width direction of the hot slab. Dies for width reduction of hot slabs. A hot slab width reduction method using the hot slab width reduction mold according to any one of claims 1 to 4, wherein the hot slab is subjected to the following condition (1). How to reduce the width.

However,
S: Reduction stroke (mm)
P: Feed pitch (mm)
td: Slab transfer start delay time (sec.)
tp: time until the mold starts to come off from the rolling dead center and reaches the top dead center; time between rolling passes (sec.)

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