JPS62238022A - Operation method for tension leveler - Google Patents

Abstract

PURPOSE:To prevent the camber variation of a strip by adjusting the intermesh of a leveler roll prior to the passing of a leveling unnecessary part, thereafter, by shifting the strip tension to a lower tension, further by performing the reverse operation after its passing. CONSTITUTION:The inlet side and outlet side bridle rolls 3, 4 are arranged for a leveler roll group 2 and on the bridle roll 4 a tracking pulse counter 5 of the strip, the rolling reduction setters 10, 11, 12, 13 performing the rolling reduction and release of leveler rolls 6, 7, 8, 9 and a load cell 14 are respectively set up. The intermesh adjustment and the high and low switching of the strip tension are performed in case of the passing of the leveling unnecessary part, by tracking the leveling unnecessary position via the signal of the pulse counter 5. In this way, the deflection variation of the strip before and behind the leveling unnecessary part can be prevented.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to the operation of a tension leveler that corrects shape defects such as partial elongation and warpage that occur during rolling of cold-rolled steel sheets, stainless steel sheets, aluminum sheets, etc. It is about the method.

(Prior art) When a conventional tension leveler is operated and a part of the strip that does not need leveling (for example, a welded part of the strip, an edge crack part, etc.) passes through the tension leveler, in order to prevent the strip from breaking due to high tension leveling, ( A
) Before the leveling unnecessary part passes through the leveler, the strip tension is switched from high tension to low tension, and the leveler roll that is compressing the strip with the optimal intermesh is simultaneously quickly opened, thereby reducing the tension and opening the intermesh. An operating method in which the part that does not require leveling is passed through the leveler in a zero state, and after passing, the leveler roll is quickly closed at the same time and the strip tension is switched from low tension to high tension, or (B) the strip is compressed. The leveler roll remains rolled at the optimal intermesh and the strip tension is switched from high tension to low tension before the part that does not require leveling passes through the leveler, and the strip tension is changed from high tension to low tension.
An operating method has been adopted in which the part that does not require leveling is passed through the leveler under an optimal intermesh, and after passing, the tension is switched from low to high.

However, when correcting the strip shape using a tension leveler, the flatness of the strip must be 9.
Warpage does not improve.

That is, as shown in Fig. 1, the flatness level 1 warping history of the strip in the leveler at a certain moment changes between each leveler roll, so in the operating method (A), the part that does not require leveling is removed before the strip passes through the leveler. When the tension is switched from high tension to low tension, the strip that has been leveled at high tension with the leveler roll up to grain (i-1) is leveled with low tension with the leveler roll from grain i to grain n, and in this way. Partial leveling does not correct the shape sufficiently.

Furthermore, even when the leveler rolls are subjected to a quick oven at the same time, the shape becomes unstable because the flatness 9 warp history between the leveler rolls is different. Conversely, when the leveler roll is quickly closed at the same time after the leveling unnecessary part passes through the leveler and the strip tension is switched from low tension to high tension, the strip leveled by the leveler roll from the 1st grain onwards will be from the 1st grain (i- 1) The shape is unstable because it is not rolled down to the grain by the leveler roll.

In the case of (B) above, when the strip tension switches between high and low tensions, the shape becomes unstable due to the above-mentioned reasons, and since leveling is performed with the leveler roll being rolled down at low tension, the shape becomes unstable. The part is longer than that of (A), which is not preferable.

The conventional operating methods (A) and (B) and the shape of the strip (flatness of 1 warpage) are shown in FIG. 2 (aOb).

In addition, the strip tension shown here is the yield stress of the strip to be corrected by YP (kg/m*''), and the strip tension is crt (kg/sr) when crt≧1
The tension where /3YP is defined as high tension, and the tension where σt<1/3YP is defined as low tension.

(Problems to be Solved by the Invention) The present invention solves the conventional problems, and eliminates the need for leveling in the strip from being broken in the leveler, and furthermore, the strip before and after the unnecessary leveling has excellent flatness, and is particularly free from warping. To provide a method of operating a tension leveler that produces good strips with less.

(Means for Solving the Problems) The present invention provides that when the shape of a strip is corrected through a tension leveler, the strip is passed under constant high tension through all the rolls of a plurality of leveler rolls which have been rolled down with an optimal intermesh. A good shape can only be obtained after being rolled into a plate, and if the strip tension changes when rolled down with a leveler roll, or if the strip is partially rolled down with a leveler roll, the shape will be poor and it is said to be undesirable. This is true based on the premise.

In particular, when the welded part in the strip passes through a tension leveler, the strip before and after the welded part has a low tension in the strip that has been rolled down by the leveler roll, resulting in poor shape. Conventionally, there was no method for correcting this defective part, and the present invention solves this problem.

That is, one aspect of the present invention is to optimize the correction conditions of the tension leveler according to the movement of the strip so that a defective shape such as a warpage does not occur when the strip passes through the leveler in a portion of the strip that does not require leveling.

The present invention will now be explained in detail using FIG. Now, when the part of the strip that does not require leveling reaches a predetermined position in front of the tension leveler (for example, the f & front roll of the priddle roll on the entry side of the tension leveler), zero the intermesh of the first leveler roll counting from the leveler population. Alternatively, the intermesh of leveler roll #2 is released or zero when the opening start point (point A in Figure 3) by leveler roll #1 reaches directly below leveler roll #2 due to downstream movement of the strip. Alternatively, by mitigating and then moving the strip downstream, A
When the point reaches leveler roll #3, the intermesh of leveler roll #3 is released, zeroed, or reduced.

Here is the explanation of the leveler roll intermeshes in the 7th section.
In the diagram, state (i) shows the optimal intermesh, (■) shows the state where the intermesh is reduced, and (2) shows the state where the intermesh is reduced.
) indicates intermesh zero, and αV) indicates intermesh open.

Furthermore, by carrying out this method toward the final leveler roll that is being rolled down, the strip upstream side from the opening start point of the first leveler roll is subjected to the optimal intermesh reduction of all leveler rolls, and from the opening start point. On the downstream side of the strip, the intermeshes of all leveler rolls are open, zero, or reduced.

Next, after point A reaches the final leveler roll #n and after the intermesh of the leveler roll #n has been opened, zeroed or reduced, the strip tension is switched from high tension to low tension. Note that points A and B in FIG. 3 indicate points approximately 2 to 5 meters away from the area where leveling is not required.

In this way, in the leveling-unnecessary portion, the intermesh of the leveler roll is opened, zeroed or reduced, and the strip tension is reduced to a low tension and the strip is passed through the leveler. On the other hand, when the part that does not require leveling reaches a predetermined position after passing through the leveler (e.g., the last roll of the priddle roll on the exit side of the tension leveler), the strip tension is changed from low to high. After switching to tension, the first leveler meal of the leveler population is rolled down with the optimum intermesh, and after rolling down, the rolling start point (point B in Fig. 3) where the leveler roll #1 rolled down is due to the downstream movement of the strip. When reaching just below leveler roll #2, leveler roll #2 is rolled down with the optimum intermesh. By carrying out this method up to the final leveler roll #n, the strip downstream from point B is under high strip tension and all the leveler rolls are rolled down.

However, if the strip to be straightened is made of a soft material or has a thick plate, when the leveler roll is rolled down under high strip tension, touch marks of the leveler roll may easily stick to the meter plate, which is undesirable. Reduction amount of leveler roll: IM (mm), span length of leveler roll and deflector roll: L (am),
Leveler roll diameter: D (am), Strip thickness: 't (am), Strip yield strength Y
P (kg/sm″), strip tension σt (kg
/m♂) then log IN/ L≧-5, 4-1, 7lag t −
σt/D fist YP ・・・・・・・・・・・・(1)
It was experimentally found that this phenomenon occurs under conditions that satisfy the following conditions.

Therefore, when formula (1) is satisfied, in order to prevent the generation of touch marks, the unnecessary part passes through the leveler,
When reaching the predetermined position, first lower the leveler roll, then switch the strip tension from low to high tension, and then lower the leveler roll to the final stage (#n) while the rolling start point B moves downstream. This makes it possible to apply all the leveler rolls below the strip downstream from point B, and also prevent the occurrence of touch marks as shown in FIG. 6, which is more effective.

As described above, the present invention is capable of improving the shape (especially warpage) over the entire length of the strip without breaking the non-leveling part in the operating method when passing through the non-leveling part of the strip.

In addition to the method described above, the method for opening and rolling down the leveler rolls is similar to that for opening and rolling down the intermesh for every number of leveler rolls, dividing the group into the leveler roll group on the entry side and the leveler roll group on the exit side. Effects can be obtained. Furthermore, #l
Among the leveler rolls up to #n, those rolls that have little effect on changes in warp of the strip can be omitted from the operations of opening and rolling down the intermesh.

Next, an example of an apparatus for implementing the present invention will be explained with reference to FIG. The leveler roll group 2 provided for leveling the strip 1, the input side priddle roll 3, the output side priddle roll 4, the pulse counter 5 for tracking the strip, and the leveler roll 6.7.8 are rolled down and released. Set the setting devices 10.11, 12.13 and the load cell 14 for measuring tension in the leveler. Then, tracking calculation is performed on the position of the unnecessary part in the strip using the pulse counter signal for strip tracking, and calculation is performed to set the tension control device 15 that controls the tension in the strip according to the downstream movement of the strip, and the intermesh of each leveler roll. By installing the device 16, the operating method of the present invention can be carried out.

FIG. 5 shows the line speed, strip tension in the leveler, leveler roll, warpage, flatness, etc. when the present invention was carried out, and it can be seen that the shape is good.

(Effects of the Invention) As described above, with the tension leveler threading method for the unnecessary leveling part of the strip according to the present invention, warping changes at the end and start of leveling of the strip before and after the leveling unnecessary part are prevented without breaking the leveling unnecessary part. This is extremely advantageous because it can improve yield and production capacity.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing changes in the shape (curvature, flatness) of the strip in the leveler according to the conventional method, and Figures 2 (a) and (b).
) is an explanatory diagram showing a conventional operating method, FIG. 3 is an explanatory diagram showing a method of passing a strip through a tension leveler according to the present invention, FIG. 4 is a block diagram showing an example of an apparatus according to the present invention, and FIG.
The figure is an explanatory diagram showing the shape when the method of the present invention is carried out.
FIG. 1 is an explanatory diagram showing the experimental results of whether roll touch marks occur or not, and FIG. 7 is an explanatory diagram showing the intermesh of a leveler roll.

Claims (1)

[Claims] 1) When correcting the shape of the part of the strip that does not require leveling using a tension leveler, before the part that does not require leveling passes through the leveler, the leveler roll that is compressing the strip with an arbitrary intermesh is moved to move the strip. While opening the intermesh of the leveler roll from the leveler roll on the input side of the leveler to the leveler roll on the exit side,
Alternatively, after the tension has been reduced to zero or reduced, the tension acting on the strip is switched from high tension to low tension,
The strip is passed through the leveler without breaking the unnecessary part, and after passing, the strip tension is switched from low tension to high tension, and the strip is moved from the leveler roll on the input side to the final leveler roll on the output side. A method of operating a tension leveler characterized by lowering a roll into a strip with an arbitrary intermesh. 2) When correcting the shape of the part of the strip that does not require leveling using a tension leveler, before the part that does not require leveling passes through the leveler, move the leveler roll that has compressed the strip using an arbitrary intermesh, and move the leveler roll on the entry side of the leveler while moving the strip. Open the intermesh of the leveler roll from the roll toward the leveler roll on the exit side,
Alternatively, after the tension has been reduced to zero or reduced, the tension acting on the strip is switched from high tension to low tension,
The leveler is passed through the leveler without breaking the part that does not require leveling, and after passing, the strip is moved and the leveler roll is rolled down onto the strip by an arbitrary intermesh from the leveler roll on the entry side to the final leveler roll on the exit side. , a method of operating a tension leveler characterized by switching the strip tension from low tension to high tension.