JP2001259772A - Die for width reduction of hot slab, transfer and pressing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die conforming to a width reduction pressing condition of a hot slab, a transfer method and a width reduction pressing method of the hot slab with using the die. SOLUTION: The die satisfies the condition in following expression in the width reduction of the hot slab. L1.sinθ1>=ΔWmax/2, L3.sinθ2>=ΔWYmax/2 L1<=L2 cosθ1, L1>=P1, H>=hs+ hs.ΔWmax/S(W-ΔWmax)}t>=ΔWmax Ra<=100 L1: inlet side inclined part length (mm), L2: parallel part length (mm), L3: outlet side inclined part length (mm), ΔWmax: maximum width rolling reduction (mm), ΔWYmax: maximum pre-forming quantity (mm), θ1: inlet side inclined angle ( deg.), θ2: outlet side inclined angle ( deg.), H: height (mm), W: maximum width of slab width passing through the equipment (mm), hs: thickness of material to be reduced (mm), Ra: initial average center line roughness of face in contact with slab (μm), P1: distance per single pressing to transfer slab for pressing (mm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die for reducing the width of a hot slab and a method of transporting and pressing the same, and more particularly, to a die for reducing the width of a hot slab and a hot die using the same. The present invention relates to a slab width reduction press method and a method for transporting a hot slab at that time.

[0002]

2. Description of the Related Art In recent years, in the production of billets, the production of raw materials (slab materials) by a continuous casting method has been dominant in place of the conventional ingot method from the viewpoint of energy saving. However, most of the slabs manufactured by the continuous casting method are of a fixed size, and have a drawback that a slab having an arbitrary width cannot be produced as in a conventional bulk slab.

As a countermeasure, a hot slab has been intermittently moved in a longitudinal direction between a pair of molds having a tapered portion and a linear portion in a slab width direction and opened and closed periodically. A width reduction press (start and stop method) that reduces the width to an arbitrary width, and a pair of dies having a tapered portion and a linear portion can be reciprocated in the width direction and reciprocated in the slab conveyance direction in the slab width direction. There has been proposed a width reduction press device of a horizontal facing type running type in which a transfer device is disposed to be opposed to and disposed upstream of the mold in the slab transfer direction. Hereinafter, these devices are collectively referred to as a width reduction press device, and a die used for the device is referred to as a width reduction die for a hot slab.

[0004] Even in the past, there have already been some proposals regarding these width reduction press apparatuses. For example, In Japanese Patent Laid-Open No. 60-247401, the feed amount of the slab is set from the amplitude and the taper angle of the mold constituting the press tool on one side, and the length of the parallel part of the mold is the feed amount of the slab, that is, one stroke. It is disclosed that the transport amount must be equal to or more than the transport amount.

Japanese Patent Laid-Open Publication No. Sho 62-282738 discloses a method of setting the conveying amount of a slab, which is a material to be pressed, per unit time based on the amplitude of the mold and the taper angle of the mold. Japanese Patent Application Laid-Open No. 7-328701 discloses a method of controlling a slab conveyance amount based on a width reduction amount, a maximum slab conveyance amount, and a mold taper angle.

Japanese Patent Application Laid-Open No. 8-224605 discloses a method of controlling a slab conveyance amount based on a width adjustment allowance, a mold stroke, a width reduction amount, a mold taper angle, and a parallel portion length.

Japanese Patent Application Laid-Open No. 9-253780 discloses a method of setting the slab conveyance amount based on the width reduction amount and the mold taper angle. Japanese Unexamined Patent Publication (Kokai) No. 61-222604 discloses a method for increasing the frictional force between the slab and the mold pressing lower surface.

[0008]

However, in the prior art as described above, there is a disclosure about a method of pressing the width of a hot slab in the shape of a mold, but conversely, various slab materials, The disclosure of optimal mold settings for various width reduction conditions has not been sufficiently made. Further, the disclosure of the method of transporting the slabs under the conditions of the width reduction of the hot slab in each hot rolling line and the method of reducing the width of the hot slab by the use of the die are insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a die which meets the conditions of the width reduction of a hot slab in each hot rolling line, a method of transporting a hot slab in each hot rolling line, and a method for transporting each slab. It is an object of the present invention to provide a width reduction press method for a hot slab using a mold meeting the width reduction press conditions.

[0010]

Means for Solving the Problems The present inventors have conducted various studies and tests to achieve the above object. As a result, it has been found that the die shape can be determined from the hot slab width reduction press conditions of each hot rolling line under the width reduction of the hot slab as described below, and the present invention has been achieved.

In the following, a hot slab to be subjected to width reduction is also referred to as a material to be pressed, or simply as a slab.

[0012]

(Equation 5) L1: Length of entrance side inclined part (mm), L2: Length of parallel part (mm), L3: Length of exit side inclined part (mm), ΔWmax: Maximum width reduction (m)
m), ΔWYmax: maximum preforming amount (mm), θ1: entrance side inclination angle
(°), θ2: Outgoing-side inclination angle (°), H: Height (mm), W: Maximum width (mm) of slab width passing through the facility, hs: Thickness of material to be pressed (mm), Ra: initial center line average roughness (μm) of the surface in contact with the material to be pressed P1: distance (mm) per press for conveying the material to be pressed for pressing, ie, width reduction of hot slab In the mold for use, the planar shape on the side where the width reduction is performed in contact with the slab is composed of an entrance-side inclined portion, a parallel portion, and an exit-side inclined portion, and is arranged to face the slab width direction. According to the present invention, such a die satisfies one or more of the above formulas (1) to (4).

In other words, it has been found that the intended object of the present invention can be attained by installing a mold having at least one or more of the parts represented by the above formulas and performing width reduction. In addition, from another aspect, using a mold designed as described above from the width reduction press conditions of the hot slab in each hot rolling line, by controlling the transfer of the slab by the following equation, it is more efficient It has been found that the width can be reduced in the range, and the present invention has been achieved.

[0014]

(Equation 6) P1: distance (mm) per press for transporting the material to be pressed for pressing, d: distance that one side of the mold opens and closes during the time per press for transporting the material to be pressed for pressing ( mm), T1: Time (seconds) per press for transporting the material to be pressed for pressing (seconds), T2: Mold on one side opens and closes for time per press for transporting the material to be pressed for pressing Time (seconds)

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described more specifically with reference to the accompanying drawings, and the reasons for defining the mold shape and the transport amount as in the present invention will be described in detail. .

According to the present invention, the dies for the width reduction presses of the start-and-stop system and the horizontal facing type running system are defined based on the conditions for the width reduction of the hot slab in each hot rolling line. .

Another object of the present invention is to provide a method of transporting a slab, which is a material to be pressed, and a method of performing a width reduction press when the above-mentioned mold is used as a die of a hot slab width reduction press apparatus.

FIGS. 1 to 7 of the accompanying drawings schematically show a mold according to the present invention. In the figure, a mold 11 has a parallel portion 21 and inclined portions 22 and 23, a height 24, a thickness 25, and inclined portion angles θ1 and θ.
2, and has an inclined portion length L _1, L _3. The inclined portion may be provided only on the entry side.

FIG. 8 is a plan view showing a slab shape during pressing, and FIG. 9 is a conceptual diagram of a width reduction press. In the figure, a pair of dies 11 are arranged opposite to each other in the width direction of a slab 12 which is a material to be pressed.

As shown in FIG. 9, the slab 12 is
Is pressed under width. Parallel part length L2, inclined part length L
1, L3, height H, length t are

[0021]

(Equation 7) L1: Length of entrance side inclined part (mm), L2: Length of parallel part (mm), L3: Length of exit side inclined part (mm), ΔWmax: Maximum width reduction (m)
m), ΔWYmax: maximum preforming amount (mm), θ1: entrance side inclination angle
(°), θ2: Discharge side inclination angle (°), H: Height (mm), W: Maximum width of slab passing through the facility (mm), hs: Thickness of material to be pressed (mm), Ra: initial center line average roughness of the surface in contact with the material to be pressed (μm) P1: distance (mm) per press for conveying a slab for pressing, at least one portion represented by the following formula: The above is formed. Further, it is preferable to form two or more portions represented by the above formula, and the more the portions formed by the above formula such as three to all portions are more suitable for a hot rolling line.

However, W (the width of the slab of the material to be pressed) in the following formula is optimal when the maximum width of the slab width of various sizes to be rolled in each hot rolling line is used.

[0023]

(Equation 8) In addition, the leading end or the rear end of the slab may be preformed as shown in FIG. 10 prior to the width reduction, but even in such a case, the present invention is applied to efficiently reduce the width reduction. It can be carried out.

Molds having a shape in which the inclined portion has a multi-step inclined portion and a shape in which the parallel portion has an arc shape between the parallel portions and between the parallel portion and the end of the inclined portion have been developed. In this case, as shown in FIG. 3, FIG. 4, FIG. 5, and FIG. 6, respectively, the inclined part lengths L1, L3, the inclined part angles θ1, θ2.
think of.

The width reduction press using a pair of dies shown in FIG. 9 is performed while the slab is opened and closed by the pair of dies (one of the dies is d.
Is transported by P1 during the round trip. The conveyance of the slab at this time is controlled by the following equation.

[0026]

(Equation 9) P1: distance (mm) per press for transferring a slab for pressing, d: distance (mm) for opening / closing one side of the mold in one press for transferring a slab for pressing. Time per press for transferring a slab for pressing (seconds), T2: Time for opening and closing one die at the time per press for transferring a slab for pressing (seconds), ie, hot When using a slab width reduction press device to reduce the width of the slab, which is the material to be reduced, at the most entry side of the entry side inclined part when performing width reduction at the entry side inclined part of the mold, There is a step between the portion that is pressed down on the most entry side of the inclined portion and the portion that is not pressed down.

When this step is increased, the amount of reduction in the subsequent reduction by the width reduction press becomes discontinuous near the most entry side of the entry side inclined portion, and the variation of the width deviation is reduced by the entry side inclination. It increases near the point where it is reduced on the most entry side of the part.

In order to prevent such a variation in the width deviation occurring near the entry side of the entry side inclined portion, a mold that does not reduce the width beyond the entry side of the entry side inclined portion is required. Need to design.

Incidentally, the maximum width reduction ΔW for each line
The max is arbitrarily determined, and the maximum width reduction in one mold is half the maximum width reduction arbitrarily determined for each line. Determined by the entry side inclination angle θ1 to the entry side inclination part length L1
Multiplying by sin θ1 determines the maximum width reduction of one mold when the width is reduced without exceeding the most entry side of the entrance side slope, and it is larger than half of the maximum width reduction arbitrarily determined for each line. Therefore, the length L1 of the entry-side inclined portion represented by the following equation is formed.

[0030]

(Equation 10) In the case where the width is reduced in order to form the preform on the exit side inclined portion, the same problem occurs as in the case where the width reduction is performed on the entrance side inclined portion, so the exit side inclined portion length L3, the exit side inclination angle θ2 When multiplied by the determined sin θ2, the maximum preforming amount of one mold when the width is reduced to form the preforming without exceeding the outermost side of the outlet side inclined part is determined, and this is arbitrarily determined for each line It must be larger than half of the maximum preforming amount ΔWYmax.
It forms L3.

[0031]

[Equation 11] Further, in the mold of the hot slab width reduction press device, the width-reduced portion of the entry side inclined portion of the material to be reduced is reduced by the parallel portion of the parallel mold to reduce the width to a predetermined width. Is done.

The material to be reduced, which has been reduced in width by the inclined portion on the entry side of the mold.
The (slab) part or the unpressed lower part is reduced by the parallel part of the mold. At this time, if the width reduced by the entry side inclined part is reduced by the parallel part (except for the initial case of reducing the width of the material to be reduced), the width reduction by the parallel part of one mold is required. The volume is a volume obtained by halving (approximately the slab thickness x the width reduction).

On the other hand, when the unpressed portion is also reduced by the parallel portion
(Except in the initial stage of width reduction of the material to be reduced)
The width reduction width in the parallel part of the two molds is the volume reduced in width on the entry side slope plus the volume reduced in width on the unpressed bottom (almost slab thickness × width reduction amount). The width reduction volume is larger than in the case where only the width-reduced portion is width-reduced in the portion, and the load during width reduction is increased.

As described above, when the load at the time of the width reduction becomes large, capital investment that can withstand the load is required. In order to suppress the capital investment, the length L2 of the parallel portion is determined by the length L1 of the entrance side inclined portion and the entrance side inclination angle θ1. It must be shorter than the length of the parallel part of the entry-side inclined part in the extension direction multiplied by the cos θ1.

When the length of the parallel portion is shorter than the distance (P1) per transfer of the material to be reduced in order to reduce the width, the portion reduced in width by the inclined portion on the entrance side of the slab cannot be reduced by the parallel portion. Therefore, the variation in the width deviation increases, so that the parallel portion length represented by the following equation is formed.

L2 ≦ L1 · cos θ1 and L2 ≧ P1 In a width reduction press of a hot slab, when the width reduction is performed, the thickness of the slab which is the material to be reduced is increased. If the height of the mold is not higher than that of the mold, a sharp recess is formed on the side surface of the slab by the mold, and a flaw may be generated on the coil edge. The mold height H must be higher than the thickness of the material to be pressed, which is the thickness hs of the material to be pressed and the thickness of the material to be pressed when the maximum width is reduced. Determined by the width reduction volume. Therefore, at this time, the height shown by the following formula is formed in the mold.

[0037]

(Equation 12) When the surface roughness of the mold of the hot width reduction press is large, irregularities are formed in the lower part of the width of the material to be reduced, and the irregularities cause flaws on the coil edge. It is necessary to reduce the center line average roughness Ra of the surface in contact with the material to be pressed, and as a result of various confirmations, a center line average roughness represented by Ra ≦ 100 is formed.

When a width reduction press is performed using the above-described mold, the material to be reduced is conveyed for pressing.
If the distance in the mold thickness direction multiplied by the tan θ1 determined from the rotation distance P1 and the entry-side inclination angle is smaller by half the distance that the mold moves during the time of moving by the distance P1, the mold is covered. The width reduction can be performed without affecting the traveling direction of the material to be reduced from the reduction material.

In addition, if the time for conveying the material to be pressed for pressing is shorter than the time for opening and closing the mold, the effect can be further increased, and the moving distance of the mold can be reduced. Thus, the impact load generated when the width is reduced can be reduced.

Next, the function and effect of the present invention will be described in more detail with reference to examples.

[0041]

EXAMPLES Assuming the pressing conditions of the hot slab shown in Table 1, the mold shape as shown in Table 2 was designed according to the above-mentioned equations based on the pressing conditions.

Then, by actually using these dies, as shown in Table 3, the feed amount of the slab in one press in the longitudinal direction, that is, the slab transfer amount was changed from 0 to 370 mm, and A width reduction press was performed.

The results are shown graphically in FIGS.
As can be seen from these results, within the range specified by the present invention, the width deviation of the slab is stable, the press load does not become excessive, and the occurrence of rolling flaws is small.

FIG. 11 shows a case where the length L1 of the entrance-side inclined portion is defined, and FIG. 12 shows a case where the length L3 of the exit-side inclined portion is defined.
13 to 15 define the length of the parallel portion, FIG. 16 defines the surface roughness, FIG. 17 defines the slab transport amount, and FIG. 18 defines the slab transport time and press time. The effect of the present invention is shown for each case.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

As described above, according to the present invention, it is possible to obtain a die shape optimal for the hot slab width reduction press conditions of each hot rolling line in which the width reduction press device is installed.

Further, according to the present invention, it is possible to obtain an optimum slab transfer amount and transfer time when such a mold is used.

[Brief description of the drawings]

FIG. 1 is a plan view of a typical mold of a hot slab width reduction press.

FIG. 2 is a plan view of another representative mold of the hot slab width reduction press.

FIG. 3 is a plan view of yet another representative mold of the hot slab width reduction press.

FIG. 4 is a plan view of yet another representative mold of the hot slab width reduction press.

FIG. 5 is a partially enlarged view of a typical mold of a hot slab width reduction press.

FIG. 6 is a partially enlarged view of another representative mold of the hot slab width reduction press.

FIG. 7 is a three-dimensional view of the mold of FIG. 1;

FIG. 8 is a schematic diagram showing an example of the shape of a hot slab in the middle of width reduction pressing by a width reduction press device.

FIG. 9 is a plan view of a mold and a hot slab in the middle of a width reduction press by a width reduction press device.

FIG. 10 is a plan view of a preformed shape of a front end portion and a rear end portion of the hot slab.

FIG. 11 is a graph showing the results of Examples.

FIG. 12 is a graph showing the results of Examples.

FIG. 13 is a graph showing the results of Examples.

FIG. 14 is a graph showing the results of Examples.

FIG. 15 is a graph showing the results of Examples.

FIG. 16 is a graph showing the results of the example.

FIG. 17 is a graph showing the results of Examples.

FIG. 18 is a graph showing the results of Examples.

[Explanation of symbols]

11: Die, 12: Material to be pressed, 21: Parallel part, 22: Inlet slope, 23: Outlet slope, 24: Height, 25: Thickness, L1: Inlet slope length (mm) , L2: length of parallel part (mm), L3: length of exit side inclined part (mm), ΔW: width reduction (mm), ΔWY: preforming amount (mm),
θ1: Entering side inclination angle (°), θ2: Outgoing side inclination angle (°)
, H: height (mm), W: maximum width (mm) of the slab width passing through the equipment, hs: thickness of the material to be pressed (mm), P1: press once to convey the slab for pressing Per distance (mm),
d: Distance (mm) that one side of the mold opens and closes in the time of one press to transport the slab for pressing

Claims (9)

[Claims] 1. A die used in a hot slab width reduction press, comprising: A width reduction die for a hot slab, comprising a length of an inlet-side inclined portion represented by the following formula: L1: Length of entry side inclined part (mm), ΔWmax: Maximum width reduction (m
m), θ1: Entry side inclination angle (°) 2. A mold for use in a hot slab width reduction press, comprising: A width reduction die for a hot slab, comprising a length of a delivery side inclined portion represented by the following formula: L3: Length of exit side inclined part (mm), ΔWYmax: Maximum preforming amount (m
m), θ2: Outgoing side inclination angle (°) 3. A width reduction machine for a hot slab, comprising: a die used in a width reduction press of a hot slab, wherein the mold has a parallel portion length represented by a formula of L2 ≦ L1cos θ1 and L2 ≧ P1. Mold. L2: Length of parallel part (mm), L1: Length of entry side inclined part (mm), θ1: Entry side inclination angle (°) P1: Distance per press (mm) for conveying material to be pressed for pressing 4. A mold for use in a hot slab width reduction press, comprising: A mold for reducing the width of a hot slab, the mold having a mold height represented by the following formula: H: mold height (mm), hs: slab thickness (mm), W: maximum width (mm) of slab width passing through the equipment, ΔWmax: maximum width reduction (mm) 5. A mold for use in a hot slab width reduction press, comprising a surface having a center line average roughness (Ra) represented by the following formula: Ra ≦ 100. Mold for width reduction. Ra: initial center line average roughness of the surface in contact with the slab (μ
m) 6. A hot slab width reduction press device, comprising:
When performing a width reduction of a hot slab using a mold that satisfies one or more of the conditions according to any one of claims 1 to 5, per press for transporting the slab as a material to be pressed. The distance is A method for conveying a hot slab, wherein the method is controlled as shown in the following formula: P1: distance (mm) per press for transferring a slab for pressing, d: distance (mm) for opening and closing one side of the mold in one press for transferring a slab for pressing, θ1 ： Incline angle (°) 7. The method for transferring a hot slab according to claim 6, wherein the time per press for transferring the slab as the material to be pressed is controlled as represented by the following equation: T1 ≦ T2. . T1: Time per press for transferring a slab for pressing (seconds), T2: Time for opening and closing one mold at the time per press for transferring a slab for pressing (seconds) 8. A mold for use in a hot slab width reduction press apparatus, wherein
A width reduction die for a hot slab, characterized by satisfying the above conditions. 9. A hot slab width reduction press, comprising:
8. A hot slab, wherein the hot slab is conveyed under the conditions specified in claim 6 or 7 using a width reduction die satisfying the conditions of any one of claims 1 to 5. Width reduction press method.