JP2005186096A - Apparatus and method for straightening steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a straightening apparatus of a steel sheet and a straightening method of it dispensing with the installation of a displacement sensor for detecting the displacement of a roll. <P>SOLUTION: This apparatus has a plurality of straightening roll groups 10U, 10D the screw-down locations of which is integrally set, one upper additional straightening roll 5U or one lower additional straightening roll 6D which is arranged above or under the pass line on the outlet side of the plurality of roll groups 10U, 10D or a pair of upper and lower additional straightening rolls 5U, 6D arranged across the pass line, and the additional straightening rolls 5U, 6D can individually freely adjust their screw-down locations. By this straightening method of a steel sheet, straightening is performed by adjusting the screw-down locations of the plurality of straightening roll groups 10U, 10D the crew-down location of which are set integrally so as to be a prescribed plastic deformation rate and also individually adjusting the displacement of the upper additional straightening roll 5U or/and the lower additional straightening roll 6D. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steel plate straightening device and a straightening method.

The hot-rolled steel sheet is re-heated in a heating furnace with a steel piece such as a slab as a raw material, and then hot-rolled by a rolling mill while removing the scale by descaling with high-pressure water, and the desired thickness, width, It becomes length. Thereafter, accelerated cooling is performed as necessary, and after further cooling in the cooling bed, the product is cut into a predetermined size to obtain a product.
A steel sheet manufactured in such a process may have a defective shape due to the temperature distribution of the steel sheet in rolling or the unevenness of elongation deformation in rolling. Causes of non-uniform temperature distribution include uneven slab heating in the heating furnace, non-uniform high-pressure water injection in descaling, influence of roll cooling water in hot rolling and cooling for controlled rolling, and Examples include non-uniform cooling in accelerated cooling after rolling.

Moreover, even if the steel plate is apparently flat, residual stress may be generated in the steel plate after cooling. In particular, the non-uniform temperature distribution of the steel sheet during rolling greatly affects the generation of residual stress because the amount of thermal shrinkage becomes non-uniform during the cooling process. These steel plates are often used after being cut into various dimensions. However, since the dimensions and shape after cutting change depending on the residual stress, it is desired to reduce the residual stress as much as possible.
When a flatness defect or residual stress occurs in a steel sheet, cold roller leveler or press correction is performed to correct this. Generally, roller levelers (hereinafter referred to as straightening devices) are often used for efficiency and cost, and not only improve flatness but also reduce residual stress remaining in steel sheets at room temperature. It is known that correction by is effective.

FIG. 8 is a side view schematically showing an example of a conventional correction device. In FIG. 8, a steel sheet straightening device 900 has a plurality of upper straightening rolls 10U and a plurality of lower straightening rolls 10D arranged in a staggered manner (hereinafter collectively referred to as a group of straightening rolls), and a material to be straightened (hereinafter referred to as a straightening roll). , Referred to as a steel plate) and repeatedly bending.
The upper straightening rolls 10U are respectively supported by the upper backup roll 20U, and the lower ends of the upper straightening rolls 10U are located in the same plane. On the other hand, the lower straightening roll 10D is similarly supported by the lower backup roll 20D, the apex (upper end) of each lower straightening roll 10D is located in the same plane, and the conveyance surface (hereinafter referred to as a pass line) of the steel plate indicated by an arrow. In parallel.

The upper backup roll 20U is attached to the upper frame 30U via a bearing, and can be adjusted by a reduction device 41 and an output side reduction device 42 on the entry side of the upper frame 30U. That is, the inlet side reduction amount and the outlet side reduction amount of the steel sheet can be set separately.
On the other hand, the lower backup roll 20D is attached to the lower frame 30D via a bearing.

  In order to facilitate the following description, a plurality of upper straightening rolls 10U are directed from the entry side to the exit side, respectively, the upper first roll 1U, the upper second roll 2U, the upper third roll 3U, and the upper 4 Similarly to the number 4U, the plurality of lower straightening rolls 10D are arranged from the entry side to the exit side, respectively, the lower 1st roll 1D, the lower 2nd roll 2D, the lower 3rd roll 3D, the lower 4th roll 4D, the lower It is called 5th roll 5D.

Further, assuming that the deformation of the steel plate is a three-point bending, the lower end of the upper i-th roll is separated from the line thickness (t) of the steel plate from the line connecting the apex of the lower i-th roll and the lower (i + 1) -th roll. When the distance (d) is subtracted, the amount (t−d), that is, when the plate thickness is regarded as 0 mm, the upper i-th line from the line connecting the vertices of the lower i-th roll and the lower (i + 1) -th roll The amount by which the lower end of the roll enters downward is referred to as the amount of rolling down of the upper i-th roll or “upper i-th rolling down amount”.
On the other hand, according to this, from the thickness (t) of the steel sheet, the distance (the upper end of the lower (i + 1) roll is separated from the line connecting the lower end of the upper i roll and the lower end of the upper (i + 1) roll ( The amount (t−d) obtained by subtracting D) is defined as the rolling amount of the lower (i + 1) th roll or “lower (i + 1) rolling amount”. At this time, since the lower No. 1 roll and the lower No. 5 roll located at both ends are not in a three-point bending state, the reduction amount is zero.

Accordingly, the upper i-th pressure reduction amount, the lower (i + 1) -th pressure reduction amount, the upper (i + 1) -th pressure reduction amount, etc., decrease in an arithmetic series from the entry side to the exit side. The reduction amount (hereinafter may be referred to as an inlet side reduction amount) is the largest, and the upper fourth reduction amount (hereinafter may be referred to as an outlet side reduction amount) is the smallest.
The distance between the upper straightening rolls 10U and the distance between the lower straightening rolls 10D are equal (hereinafter referred to as roll pitch), and the distance between the upper straightening roll and the nearest lower straightening roll is half of the roll pitch. That is, all the correction rolls are arranged in a staggered pattern at equal intervals in the pass line direction.

FIG. 9 is a correlation diagram showing the relationship between the reduction setting and the warp height in the correction apparatus. This is an analysis result when a steel plate having a plate thickness of 25 mm and a yield stress of 400 MPa is passed through a straightening device having a roll pitch of 300 mm while changing the entry side and exit side reduction amounts.
In FIG. 9, the horizontal axis is the output side reduction amount, and the vertical axis is the warp height, which is the maximum distance between a wide 1 m long string and a steel plate (arc). In the side view, the concave shape is referred to as an upward warp and is in the positive range of the vertical axis, while in the side view, the concave shape is referred to as the downward warp and is described in the negative range of the vertical axis.

The tendency will be described with reference to an example in FIG. 9 where the entry side reduction amount is 2.9 mm. When the delivery-side reduction amount is 0.0 mm, an upward warp of a warp height of 13 mm occurs. At this time, the upper third rolling reduction amount is 1.0 mm, but the subsequent lower fourth rolling reduction amount is as small as 0.5 mm, so that the plastic bending (upward warping) by the upper third roll is the next. The correction is completed only by receiving the elastic bending (upward warpage) in the last upper fourth roll without being canceled by the plastic bending (lower warping) in the lower No.4 roll.
Further, when the outlet side reduction amount is 0.5 mm, the warp height is −4 mm. At this time, the lower No. 4 rolling amount becomes as large as 0.9 mm, and the plastic bending (upward warping) by the upper third roll (down amount of 1.3 mm) is offset by the plastic bending (downward warping) by the lower No. 4 roll. The However, since the amount of reduction of the last upper fourth roll is as small as 0.5 mm, the influence of this bending remains and warps.

Further, when the outlet side reduction amount is 0.9 mm, an upward warp of the warp height of 16 mm occurs. At this time, the lower No. 4 rolling amount is 1.2 mm, and the lower No. 4 roll tends to warp downward by the lower No. 4 roll, but is canceled by the strong plastic bending (upward warping) by the upper No. 4 roll. Furthermore, the plastic bending (upward warping) remains after correction.
In this way, when the exit side rolling amount is gradually increased from 0.0 mm, the influence of plastic bending on the exit side rolls such as the upper third roll, the lower fourth roll, and the upper fourth roll changes. , Warping and warping are repeated. Further, if the outlet side reduction amount becomes too large, the last plastic bending (upward warp) in the upper fourth roll remains after correction, and thus a very large upward warp occurs.

These tendencies are the same when the entry side reduction amount is small, but the maximum values of upward and downward warping appearing repeatedly are small. For example, when the input side reduction amount is 1.1 mm, all the ranges are within the allowable range if the output side reduction amount is 0.7 mm or less.
Regardless of the warp height of the steel plate before straightening, in order to obtain a steel plate that has been straightened to the desired flatness, a large plastic bend is applied to the first and second rolls in the first half of the straightening. Need to offset the initial warpage.
Further, in order to reduce the residual stress, it is said that bending under a condition that the ratio of the plastic region in the thickness direction (hereinafter referred to as the plastic deformation rate) exceeds 80% is effective. Note that the plastic deformation rate of 80% indicates a state where 10% is in the elastic range from the neutral point of bending to the top and bottom in the thickness direction, and the rest is yielded.

The plastic deformation rate η is determined by the entry side reduction amount δ, and is derived from the following relational expression. The greater the entry side reduction amount, the greater the plastic deformation rate.
η = 1 − {(2σe) / (Et)} / {(mδ) / (L / 2) / (L / 2)}
η = 1−1 / K
K = κ / κe
κe = (2σe) / (Et)
κ = mδ / (L * L / 4)
Where σe: yield stress of the steel sheet
E: Young's modulus of steel sheet
t: Steel plate thickness
δ: Rolling amount
L: Roll pitch
m: Constant determined empirically (m = 6 is proposed)

At this time, since the plate thickness is 25 mm and the yield stress is 400 MPa,
When the inlet side rolling amount is 2.9 mm, the plastic deformation rate is 80%.
When the inlet side rolling amount is 2.3 mm, the plastic deformation rate is 75%.
When the inlet side rolling amount is 1.7 mm, the plastic deformation rate is 67%.
The case where the inlet side rolling amount is 1.1 mm corresponds to a plastic deformation rate of 50%.
However, in order to obtain a sufficient straightening effect, if the entry-side reduction amount is increased and the plastic deformation rate is increased, there are many cases where the exit-side warp is not satisfied. In the case of FIG. 9, when the entry side reduction amount is 2.9 mm, it is necessary to set the output side reduction amount within a range of about 0.55 mm to 0.75 mm. This is probably because the roll-out reduction amount exceeds the permissible range due to the roll escape due to, the steel plate yield stress, the variation in the plate thickness, and the like.

  Therefore, in order to eliminate the influence of the roll setting accuracy, the relationship between the output side reduction amount and the warp curvature of the material to be corrected is obtained in advance for the input side reduction amount, and based on these results, the setting position of the output side roll is determined. However, there is a problem that the effect of reducing the warp height is not sufficiently exhibited. For this reason, in recent years, the ratio of satisfying high specifications required for steel sheets (for example, warp height ± 3 mm or less) by one-pass correction work has decreased, and another correction work has occurred (for example, Patent Documents). 1).

  Further, as a method for setting the correction roll position with high accuracy, a method is disclosed in which the amount of displacement is estimated based on the reaction force during correction, and the reduction amount is corrected. However, there is a problem that a highly accurate setting cannot be achieved without means for accurately evaluating the displacement of the correction roll in which the deformation of the entire frame and the deformation of each roll are superimposed (see, for example, Patent Document 2).

Therefore, as a method for accurately evaluating the displacement of the straightening roll, a method using a stiffness matrix is shown, and a method for creating a stiffness matrix is disclosed. In other words, a load is applied to each roll, the displacement of each roll due to the load is sampled for a plurality of load patterns, and a rigid matrix that correlates the load and displacement of each roll is used to accurately determine the displacement of the correction roll. (For example, refer to Patent Document 3, hereinafter referred to as the prior art).
Japanese Patent Laid-Open No. 11-226641 (page 3-4, FIG. 1) Japanese Patent Laid-Open No. 11-192510 (page 3, FIG. 1) Japanese Patent Laid-Open No. 11-104728 (page 3-7, FIG. 3)

However, in the prior art, in order to correctly detect the displacement amount of the roll in the roller leveler (same as the straightening device), it is necessary to fix one end of the displacement amount sensor to a portion that is not affected by the deformation of the straightening machine. On the other hand, there is a problem that the housing of the straightening machine cannot be attached to the roller leveler body because the housing of the straightening machine is stretched and also deformed flexibly.
Further, since the backup roll and the frame are provided, the roll cannot be seen directly from the outside of the straightening device, so that there is a problem that it is very difficult to accurately measure the displacement amount of the roll.

For this reason, a displacement and load measurement method using a “reference test piece” has been proposed, but this is an indirect measurement, and there is no guarantee that the stiffness matrix calculated by this result has sufficient accuracy. There's a problem.
Further, in order to appropriately correct the stiffness matrix that changes in accordance with the wear of the roll, it is necessary to frequently perform measurement using a reference test piece, which is not practical.
Furthermore, the final setting is made based on the prediction formula for each roll reaction force. However, since the yield stress of the steel sheet necessary for the prediction of the roll reaction force varies by about 5%, it is always the optimal setting. There is a problem that it is difficult to say.

  The present invention has been made to solve the above problems, and does not require special measurement, and can be corrected without causing warpage even if there is a variation in yield stress. An object of the present invention is to provide a straightening device and a method for straightening a steel plate using the straightening device for the steel plate.

(1) The steel sheet straightening device according to the present invention can independently adjust a plurality of straightening roll groups in which the rolling down positions are set integrally, and the rolling down positions arranged on the exit side of the plurality of roll groups. It has one straightening roll.
(2) In addition, a plurality of correction roll groups in which a reduction position is integrally set, and a reduction position can be independently adjusted, which are arranged so as to sandwich a pass line on the exit side of the plurality of roll groups. It has a pair of straightening rolls.

(3) Furthermore, the correction method of the steel sheet of the present invention adjusts the reduction positions of a plurality of correction roll groups in which the reduction positions are integrally set so as to obtain a predetermined maximum plastic deformation rate, and also corrects the plurality of corrections. The correction is performed by independently adjusting the reduction position of the correction roll disposed on the exit side of the roll group.

  In the steel sheet straightening method and straightening apparatus of the present invention, the steel sheet can be straightened in one pass without particularly adjusting the reduction setting, and the work efficiency can be improved by reducing the number of passes and the adjustment time. Can do. Furthermore, since it can be implemented simply by providing a new straightening roll on the exit side of the existing straightening device, no major equipment modification is required.

  Hereinafter, as a first embodiment, one straightening roll is added above the pass line on the exit side (downstream side) of the conventional straightening device 900 (see FIG. 8), and as the second embodiment, the exit side (downstream side). Then, what added one straightening roll below the pass line, and what added a pair of straightening rolls sandwiching the pass line on the exit side (downstream side) as Embodiment 3 will be described. In the following drawings and FIG. 8, the same parts are denoted by the same reference numerals, and a part of the description is omitted.

[Embodiment 1]
FIG. 1 is a side view schematically showing Embodiment 1 of a steel sheet straightening device according to the present invention.
In FIG. 1, a steel sheet straightening machine 100 (hereinafter referred to as a straightening machine) is provided with an upper additional frame 130U on the exit side of the steel sheet straightening machine 900 shown in FIG. The upper additional roll) is arranged. The upper additional roll 5U can be adjusted by the upper additional reduction device 140U independently of the upper frame 30U (a group of upper correction rolls 10U are installed). A table roll 800 is provided on the downstream side.
An upper additional backup roll may be arranged on the upper additional roll 5U in accordance with the upper backup roller 20U.

FIG. 2 is a correlation diagram showing the relationship between the amount of displacement of the upper additional roll 5U and the warp height in Embodiment 1 of the steel sheet straightening method according to the present invention, where the vertical axis represents the warp height of the steel plate after straightening, The horizontal axis represents the amount of displacement of the upper additional roll 5U.
At this time, the amount of reduction of the lower No. 5 roll 5D (lower No. 5 reduction amount) is as follows from the thickness (t) of the steel plate from the line connecting the apex of the upper No. 4 roll 4U and the lower end of the upper additional roll 5U. The distance (d) to the top of the 5th roll is an amount obtained by subtracting (t−d).
Further, the displacement amount of the upper additional roll 5U is the highest among the table roll 800 located further downstream from the apex of the lower fifth roll 5D from the thickness (t) of the steel plate, similarly to the reduction amount of the straightening roll. When the distance (h) between the plane connecting the apex of the roll close to the straightening machine and the lower end of the upper additional roll 5U is subtracted (th), that is, when the thickness of the steel sheet is 0.0 mm, The amount by which the lower end of the upper additional roll 5U protrudes downward from the plane is defined as a positive reduction amount.

In the straightening machine 100, the upper additional roll 5U is installed on the exit side (downstream side) from the center of the lower fifth roll above the pass line at a position of 350 mm (center-to-center distance) so as to be movable up and down independently. . At this time, the distance of the table roll 800 to the center of the roll closest to the straightening machine is 950 mm. Note that the plate thickness of 25 mm, the yield stress of 392 MPa, the roll pitch of the straightening roll group of 300 mm, and the input side reduction amount and the output side reduction amount, which are parameters, are in accordance with FIG. And
(A) In the case where the entrance side reduction amount is 2.9 mm (plastic deformation rate 80%) and the exit side reduction amount is 0.9 mm with a large warp height (upward warp) after correction (see “Position a” in FIG. 9). )When,
(B) When flattened after correction, when the entry side reduction amount is 2.9 mm and the exit side reduction amount is 0.7 mm (see “position b” in FIG. 9),
(C) Three levels are shown when the inlet side reduction amount is 2.9 mm and the outlet side reduction amount is 0.5 mm (see “Position C” in FIG. 9). Yes.
In addition, the allowable height of upper warpage is 3.0 mm, and the allowable height of downward warpage is −3.0 mm.

(A) When the output side reduction amount is 0.9mm (curve a) with a large warp height after correction, when there is no upper additional roll 5U, the warp height of 16mm may be added. As the rolling amount of the roll 5U increases, the upper warping height decreases rapidly, and when the rolling amount becomes 4.5 mm or more, the lower warping occurs.
That is, by providing the upper additional roll 5U, three-point bending (lower warp) is applied to the steel plate by the upper fourth roll 4U, the lower fifth roll 5D, and the upper additional roll 5U. That is, as the amount of displacement of the upper additional roll 5U increases, the lower fifth reduction amount increases, the plastic bending (lower warping) by the lower fifth roll 5D increases, and the plastic bending (upward warping) by the upper fourth roll. By canceling out, the influence of plastic bending in the upper fourth roll 4U is reduced.

Therefore, when the displacement amount of the upper additional roll 5U is in the range of 4.0 mm to 5.3 mm (the lower fifth reduction amount is the same as the range of 1.8 mm to 2.2 mm), the warped height of the steel sheet after correction. Is suppressed within an allowable range (+3.0 mm to −3.0 mm).
At this time, the reason why the lower fifth reduction amount and the displacement amount of the upper additional roll 5U are larger than the reduction amount of the other rolls is because the roll pitch is wide, and the reduction amount δ and the bending curvature. Relational expression of κ κ = mδ / (L * L / 4)
Where m is a constant determined experimentally,
L: As can be seen from the roll pitch, the applied curvature is not particularly large.

(B) Further, when the delivery side reduction amount that becomes flat after correction is 0.7 mm (curve b), when the displacement amount of the upper additional roll 5U is 4.0 mm or less (lower fifth roll reduction amount 1.7 mm), Since the bending at the lower No. 5 roll is within the elastic range, the warp height of the steel sheet does not change, but when it exceeds 4.0 mm, the influence of plastic bending (lower warping) by the lower No. 5 roll 5D gradually increases. The warp height becomes smaller.
At this time, if the amount of displacement of the upper additional roll 5U is set to less than 5.8 mm, the warped height of the straightened steel sheet is within an allowable range without causing harmful downward warping (+3.0 mm to −3.0 mm). )It is in.

  (C) Furthermore, when the delivery side reduction amount at which the downward warpage occurs after correction is 0.5 mm (curve c), the displacement amount of the upper additional roll 5U is 6.0 mm (lower fifth reduction amount 2.2 mm) or less. In the range, only the elastic bending occurs in the lower fifth roll, and thus the effect of the upper additional roll 5U does not appear.

  (D) It should be noted that the curve when the output side reduction amount is 0.8 mm (not shown) is between the curve a and the curve b, and the curve to the right is gentler than the slope of the curve a. On the other hand, the curve when the output side reduction amount is 1.0 mm, 1.1 mm or the like (not shown) is above the curve a, and the downward slope becomes steeper than the curve a.

  FIG. 3 is a correlation diagram showing the effect of the upper additional roll in Embodiment 1 of the steel sheet straightening method according to the present invention. A steel sheet having a plate thickness of 25 mm and a yield strength of 400 MPa is subjected to an inlet side reduction amount of 2.9 mm (plastic deformation). This is a case where correction is performed at a rate of 80%). In FIG. 3, the vertical axis is the output side reduction amount (same as the upper fourth reduction amount), the horizontal axis is the displacement amount of the upper additional roll 5U, and the warp height is within the allowable range in the combination of both. Shown with double diagonal lines.

In FIG. 3, the displacement amount of the upper additional roll 5U is in the range of 3.5 to 5.2 mm when the outlet side reduction amount is 0.9 mm (the same as the lower fifth reduction amount of 1.7 to 2.2 mm). ), A desired correction effect can be obtained.
Similarly, when the output side reduction amount is 1.0 mm, the displacement amount of the upper additional roll 5U is in the range of 3.5 to 4.7 mm (the lower fifth reduction amount is the same as the range of 1.8 to 4.7 mm). If set, the displacement amount of the upper additional roll 5U is 3.0 to 4.2 mm when the outlet side reduction amount is 1.1 mm (the same as the lower fifth reduction amount of 1.7 to 2.0 mm). If it is set within the range, a desired correction effect can be obtained.

From these, if the displacement amount of the upper additional roll 5U is set in the range of 4.0 mm to 4.5 mm, the warp height of the product is allowed even if the outlet side reduction amount varies from 0.6 mm to 1.1 mm. It can be seen that it falls within the range (range of ± 3 mm). In other words, when the upper additional roll 5U is not used, the allowable range of the outlet side reduction amount that had to be set between 0.6 mm and 0.7 mm is more than doubled to 0.6 mm to 1.1 mm. It becomes easy to achieve both reduction of the residual stress and the product warp height under the entry-side strong rolling condition that spreads and the plastic deformation rate reaches 80%.
In addition, in the range where the delivery side reduction amount is 0.75 mm or less, the upper side roll 5U is not warped more than the allowable value only in the correction roll group (see FIG. 9). It can be said that the lateral reduction amount was achieved in the range of 0.75 mm to 1.1 mm.

[Example 1]
In the straightening machine 100, a steel plate having a plate thickness of 25 mm, a plate width of 3000 mm, and an average yield stress of 400 MPa is applied to an inlet-side reduction amount (upper first reduction amount) of 2.9 mm (plastic deformation rate of 80%) and an outlet-side reduction amount of 0. Correction was performed with a straightening machine set to 8 mm and the displacement of the upper additional roll 5U was 4.5 mm. The specifications of the straightening machine 100 are as follows.
Number of upper straightening rolls 10U: 4 Roll diameter of upper straightening roll 10U: 280mm
Number of lower straightening rolls 10U: 5 Roll diameter of lower straightening roll 10D: 280 mm
Roll pitch: 300mm
Upper additional roll 5U roll diameter: 440 mm
Center distance between upper additional roll 5U and lower fifth roll 5D in the pass line direction: 350 mm
The distance between the center of the upper additional roll 5U and the table roll 800 closest to the straightening machine: 950 mm

That is, the plastic deformation rate is set to 80% so that a sufficient residual stress reduction effect can be obtained, and the upper additional roll 5U has a large effect, and the upper warp is likely to occur.
At this time, because the yield stress had a variation (variation) of ± 20 MPa due to the amount of variation in the components and manufacturing conditions, the correction reaction force varied by ± 800 kN (kilonewtons),
Entry side reduction amount (upper first reduction amount) is 2.6 mm to 3.2 mm (2.9 mm ± 0.3 mm)
The outlet side reduction amount (upper fourth reduction amount) varied in the range of 0.5 mm to 1.1 mm (0.8 mm ± 0.3 mm).

As a result of correcting the 105 steel plates, the warp height after correction was within the reference range with 91 steel plates (86.7%), but the remaining 14 sheets were out of the standard due to the downward warp. Occurred.
In particular, in the steel sheet with a low yield stress, the straightening reaction force is small, so that the outgoing side reduction amount is larger than the set value, and as shown in FIG. The upper warp is suppressed by the action of the additional roll 5U. On the other hand, in the steel sheet having a high yield stress, since the straightening reaction force was large, the amount of outgoing side reduction was too small, and the occurrence of warping was observed.

[Embodiment 2]
FIG. 4 is a side view schematically showing Embodiment 2 of the steel sheet straightening device according to the present invention.
In FIG. 4, a steel plate straightening machine 200 (hereinafter referred to as a straightening machine) is provided with a lower additional frame 130D on the exit side of the steel plate straightening machine 900 shown in FIG. (Referred to as a lower additional roll). The lower additional roll 6D can be adjusted in the reduction position by the lower additional reduction device 140D. A table roll 800 is provided on the downstream side.
Note that the lower additional backup roll may be arranged in the lower additional roll 6D in accordance with the lower backup roll 20D.

FIG. 5 is a correlation diagram showing the effect of the lower additional roll in Embodiment 2 of the steel sheet straightening method according to the present invention. It is a correlation diagram which shows the effect of the lower additional roll in the straightening method of the steel plate concerning the present invention, and when a steel plate with a plate thickness of 25 mm and a yield strength of 400 MPa is straightened with an entry side rolling amount of 2.9 mm (plastic deformation rate of 80%) It is. In FIG. 5, the vertical axis is the output side reduction amount (same as the upper fourth reduction amount), the horizontal axis is the displacement amount of the lower additional roll 6 </ b> D, and the warp height is within the allowable range in the combination of both. Is indicated by double diagonal lines.
Here, the amount of displacement of the lower additional roll 6D is such that the vertex of the lower additional roll 6D is from the plane connecting the vertices of the lower correction roll 10D (same as the plane connecting the vertices of the lower fourth roll and the lower fifth roll). It is the amount protruding upward. The distance in the pass line direction between the center of the lower additional roll 6D and the center of the lower fifth roll is 500 mm.

When the lower additional roll is not installed, the lower warp was out of the allowable range when the outlet side roll amount was 0.5 mm, but the upper fourth roll was reduced by increasing the displacement of the lower additional roll 6D. The amount is increased, the plastic bending (upward warpage) of the upper 4th roll is increased, and the downward warping of the product is suppressed.
Further, when the displacement amount of the lower additional roll 6D is increased, the plastic bending (upward warpage) in the upper fourth roll becomes too large, resulting in the occurrence of upward warping.
When the lower additional roll 6D is not used, since the downward warpage exceeding the allowable range occurs when the outlet side reduction amount is 0.5 mm (see FIG. 9), the appropriate outlet side reduction amount region is 0.3 to 0. .4 mm or 0.6 to 0.7 mm. However, by setting the amount of displacement of the lower additional roll 6D in the range of 0.5 mm to 1.0 mm, the allowable range of the outlet side roll amount is continuously increased to about 0.3 to 0.6 mm, which is about twice as large.

[Example 2]
In the straightening machine 200, a steel plate having a plate thickness of 25 mm, a plate width of 3000 mm, and an average yield stress value of 400 MPa, an input side reduction amount (upper first reduction amount) of 2.9 mm (plastic deformation rate of 80%) and an output side reduction amount of 0 Correction was performed with a straightening machine set to 0.5 mm and the set amount of the lower additional roll 6D to 0.5 mm. The specifications of the straightening machine 200 are as follows.
Number of upper straightening rolls 10U: 4 Roll diameter of upper straightening roll 10U: 280mm
Number of lower straightening rolls 10U: 5 Roll diameter of lower straightening roll 10D: 280 mm
Roll pitch: 300mm
Lower additional roll 6D roll diameter: 440 mm
Center distance in the pass line direction between the lower additional roll 6D and the lower fifth roll 5D: 500 mm
That is, the plastic deformation rate is set to 80% so that a sufficient residual stress reduction effect can be obtained, and the output side reduction amount and the set amount of the lower additional roll 6D are set to the conditions that maximize the effect in the correlation diagram of FIG.

Also at this time, because the yield stress had a variation (variation) of ± 20 MPa due to the amount of variation in the components and manufacturing conditions, the correction reaction force fluctuated by ± 800 kN,
Entry side reduction amount (upper first reduction amount) is 2.6 mm to 3.2 mm (2.9 mm ± 0.3 mm)
Outlet side reduction amount (upper fourth reduction amount) is 0.2mm to 0.8mm (0.5mm ± 0.3mm)
Fluctuated in the range.
As a result of correcting the 70 steel plates, the warp height after correction was within the reference range with 49 (70%) steel plates, but 15 plates were warped due to the large amount of output side reduction. , 6 sheets were warped due to the small amount of the exit side reduction, and were outside the allowable range of the warp height.

[Embodiment 3]
FIG. 6 is a side view schematically showing Embodiment 3 of the steel sheet straightening device according to the present invention.
In FIG. 6, a steel plate straightening device 300 (hereinafter referred to as a straightening machine) is provided with a lower additional frame 130D on the exit side of the lower frame 30D, and a straightening roll 6D (hereinafter referred to as a lower additional roll) on the lower additional frame 130D. Is arranged. The lower additional roll 6D is located on the exit side of the upper additional roll 5U, and is lowered by the lower pressure reducing device 140D independently of the upper frame 30U (a group of upper straightening rolls 10U are installed) and the upper additional roll 5U5D. The position is adjustable. The distance in the pass line direction between the center of the upper additional roll 5U and the center of the lower additional roll 6D is 950 mm, and a table roll 800 is provided on the downstream side.

By arranging the lower additional roll 6D, a three-point bend is provided between the lower straightening roll 5D, the upper additional roll 5U, and the lower additional roll 6D.
At this time, a value obtained by subtracting the distance (d1) at which the lower end of the upper additional roll 5U is separated from the line connecting the top of the lower 4th roll and the top of the lower 5th roll from the thickness (t) of the steel plate (t) -D1) is the amount of displacement of the upper additional roll 5U.
As for the lower additional roll 6D, as in the second embodiment, from the thickness (t) of the steel plate, from the line connecting the vertex of the lower fourth roll 4D and the vertex of the lower fifth roll 5D, A value (t−d3) obtained by subtracting the distance (d3) at which the apex protrudes is the amount of displacement of the lower additional roll.

FIG. 7 is a correlation diagram showing the effects of the upper additional roll and the lower additional roll in Embodiment 3 of the steel sheet straightening method according to the present invention, in which a steel sheet having a thickness of 25 mm and a yield strength of 400 MPa is reduced by an entry side reduction amount of 2. 9 mm (plastic deformation rate 80%) and the amount of displacement of the lower additional roll 6 </ b> D is corrected to −2 mm. In FIG. 7, the vertical axis is the output side reduction amount (same as the upper fourth reduction amount), the horizontal axis is the displacement amount of the upper additional roll 5U, and the warp height is within the allowable range in the combination of both. Is indicated by double diagonal lines.
At this time, the lower additional roll 6D is positioned below the lower correction roll group, but the displacement amount of the upper additional roll 5U is larger than the reduction amount of the upper fourth roll, and from the plate thickness (t) of the steel plate. The value (t−d5) obtained by subtracting the distance d5 at which the lower end of the upper additional roll 5U is separated from the line connecting the vertices of the lower fifth roll 5D and the lower additional roll 6D becomes a positive value (+ value). Therefore, bending of the upper warp by the upper additional roll 5U is given.

In FIG. 7, it can be seen that the downward warping region seen in FIG. 3 is almost eliminated. This is because the downward warping is corrected by the bending to the upward warping by the upper additional roll 5U.
For example, when the output side reduction amount is 0.5 mm, when the displacement amount of the upper additional roll 5U is as small as 2.5 mm, since the bending at the upper additional roll 5U is small, the downward warping remains. If it becomes larger than 3.0 mm, plastic bending occurs in the upper additional roll 5U, so that downward warping is suppressed.
Further, when compared with the case where the output side reduction amount is 1.0 mm, when the displacement amount of the upper additional roll 5U is as small as 3.5 mm or less, it originally warped, so the effect of the lower additional roll was completely seen. Absent.

On the other hand, when the amount of displacement of the upper additional roll 5U exceeds 4 mm, the effect of the upper additional roll 5U appears and the downward warping is suppressed, and when the amount of displacement of the upper additional roll 5U is 5 mm or more, the upper additional roll 5U is added. Due to the effect of plastic bending at the roll 5U, the warping occurs. If the amount of displacement of the upper additional roll 5U exceeds 5.5 mm, the plastic bending at the upper additional roll 5U becomes too large, and the upper warp becomes large and exceeds the allowable range.
Thus, since the correction effect of the downward warping seen only with the upper additional roll 5U is obtained, the setting allowable range is greatly expanded. In the range shown in FIG. The setting of 0.9 mm and the displacement amount of the upper additional roll 5U of 4.0 mm to 6.5 mm is allowed, and the area is about three times that of the case of the upper additional roll 5U alone.

[Example 3]
In the straightening machine 300, a steel plate having a plate thickness of 25 mm, a plate width of 3000 mm, and an average yield stress value of 400 MPa, an input side reduction amount (upper first reduction amount) of 2.9 mm (plastic deformation rate of 80%) and an output side reduction amount of 0 Correction was performed with a straightening machine that was set to 0.7 mm, the displacement of the upper additional roll 5U was 4.5 mm, and the amount of reduction of the lower additional roll 6D was -2.0 mm. The specifications of the straightening machine 300 are as follows.
Number of upper straightening rolls 10U: 4 Roll diameter of upper straightening roll 10U: 280mm
Number of lower straightening rolls 10U: 5 Roll diameter of lower straightening roll 10D: 280 mm
Roll pitch: 300mm
Upper additional roll 5U roll diameter: 440 mm
Center distance between upper additional roll 5U and lower fifth roll 5D in the pass line direction: 350 mm
Lower additional roll 6D roll diameter: 440 mm
Center view distance in the pass line direction between the lower additional roll 6D and the upper additional roll 5U: 950 mm

That is, the plastic deformation rate was set to 80% so that a sufficient residual stress reduction effect was obtained, and the exit side rolling amount was set to a condition that an almost flat plate was obtained without an additional roll.
At this time, due to fluctuations in components and manufacturing conditions, there was a fluctuation (variation) in the yield stress of ± 20 MPa, so the correction reaction force fluctuated by ± 800 kN,
Entry side reduction amount (upper first reduction amount) is 2.6 mm to 3.2 mm (2.9 mm ± 0.3 mm)
Outlet side reduction amount (upper fourth reduction amount) is 0.4mm to 1.0mm (0.7mm ± 0.3mm)
Fluctuated in the range. As a result of correcting the 120 steel plates, the warp height after correction was within the reference range for all the steel plates (100%).

[Comparative example]
In the straightening machine 300, a steel plate having a plate thickness of 25 mm, a plate width of 3000 mm, and an average yield stress value of 400 MPa, an input side reduction amount (upper first reduction amount) of 2.9 mm (plastic deformation rate of 80%) and an output side reduction amount of 0 Correction was performed in a state where the upper additional roll 5U and the lower additional roll 6D were sufficiently retracted.
At this time, due to fluctuations in components and manufacturing conditions, there was a fluctuation (variation) in the yield stress of ± 20 MPa, so the correction reaction force fluctuated by ± 800 kN,
Entry side reduction amount (upper first reduction amount) is 2.6 mm to 3.2 mm (2.9 mm ± 0.3 mm)
Outlet side reduction amount (upper fourth reduction amount) is 0.4mm to 1.0mm (0.7mm ± 0.3mm)
Fluctuated in the range. As a result of correcting the 70 steel plates, only 30 (42.9%) warp heights were within the reference range.

As described above, Embodiments 1 to 3 are composed of four upper straightening rolls 10U and five lower straightening rolls 10D. The lower straightening roll is fixed, and the reduction amount is set only by the upper straightening roll. However, the present invention is not limited to this, and the number of the upper straightening rolls 10U and the lower straightening rolls 10D, the interval between the rolls in the pass line direction, and the roll diameter can be appropriately selected as predetermined values. is there.
Further, for example, even when the reduction amount is set by the lower correction roll 10D, or when the reduction amount can be set by moving the upper correction roll 10U and the lower correction roll 10D, it is determined by the positional relationship between the three adjacent rolls. Only the concept of the amount of reduction is different, and the displacement setting method of the correction roll to be added is the same as described above.

  INDUSTRIAL APPLICABILITY The present invention can be used for a correction apparatus and a correction method used for correcting general steel sheets such as steel and stainless steel, and nonferrous metals such as aluminum and copper.

The side view which shows Embodiment 1 of the correction apparatus of this invention. The correlation diagram which shows the effect of the upper additional roll in the correction method of this invention. The correlation diagram which shows the effect of the upper additional roll in the correction method of this invention. The side view which shows Embodiment 2 of the correction apparatus of this invention. The correlation diagram which shows the effect of the lower additional roll in the correction method of this invention. The side view which shows Embodiment 3 of the correction apparatus of this invention. The correlation diagram which shows the effect of the upper and lower additional roll in the correction method of this invention. The side view of an example of the conventional correction apparatus. The correlation diagram which shows the relationship between the reduction setting and curvature height in the conventional correction apparatus.

Explanation of symbols

5U Upper additional roll 6D Lower additional roll 10D Lower straightening roll 10U Upper straightening roll 20U Upper backup roll 20D Lower backup roller 30U Upper frame 30D Lower frame 41 Input side reduction device 42 Outlet reduction device 100 Straightening machine 130U Upper additional frame 130D Lower addition Frame 140U Upper additional reduction device 140D Lower additional reduction device 200 Correction device 300 Correction device

Claims (3)

  A plurality of correction roll groups in which a reduction position is integrally set, and a single correction roll that is arranged on the exit side of the plurality of roll groups and can independently adjust the reduction position. Steel sheet straightening device.   A plurality of correction roll groups in which the reduction position is integrally set, and a pair of correction rolls that are arranged so as to sandwich the pass line on the exit side of the plurality of roll groups, each of which can independently adjust the reduction position An apparatus for correcting a steel sheet, comprising: While adjusting the reduction position of a plurality of correction roll groups in which the reduction position is integrally set so as to have a predetermined maximum plastic deformation rate, the reduction position of the correction rolls arranged on the outlet side of the plurality of correction roll groups A steel plate straightening method, characterized in that straightening is performed independently.

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