JPH0386309A - Rolling method for strip - Google Patents

Abstract

PURPOSE:To prevent an initial wedge an initial camber remaining until the final stand outlet side by performing a rolling reduction leveling control which reduces the initial wedge in the front stage pass and performing a rolling reduction leveling control for the initial camber in the rear stage pass. CONSTITUTION:In the case of performing the finish rolling of a strip 4 subjected to hot rough rolling with finish tandem type continuous hot rolling mills No. 1 - No. 7, the camber and wedge quantities of the end part of the strip 4 are measured by a camber gage 5 and wedge gage 6 at the inlet side of the rolling mills No. 1 - No. 7 at specific intervals. At the front stage stands of the rolling mills No. 1 - No. 7 a rolling reduction levelling control which reduces the initial wedge by changing the rolling reduction levelling quantity based on the wedge quantity is performed. At the rear stage stands of the rolling mills No. 1 - No. 7, a rolling reduction levelling control which reduces the remaining camber by performing the change of the rolling reduction levelling quantity equivalent to the tracking value of the camber quantity for the part where the wedge control of the strip above is performed is executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the present invention, in which a hot rough rolled strip is finish rolled in a finishing tandem continuous hot rolling mill, The present invention relates to a rolling method that prevents camber and wedge from remaining until the exit side of the final stand.

[Conventional technology]

When finish rolling a strip (copper strip) using a tandem continuous hot rolling mill (hereinafter simply referred to as a finishing tandem rolling mill), there is a camber (left and right side bending) occurs,
Accidents may occur due to collisions with the rolling mill housing or side guides, or trimming troubles and yield reductions may occur in post-processes.

Conventionally, as a method to prevent this, for example,
As disclosed in Japanese Patent No. 7-11724, the amount of wedge at the tip of the strip (the difference in thickness between the left and right sides when looking at the cross section of the strip) is measured in advance with a thickness needle installed on the inlet side of the rolling machine, and this wedge is There is a method of adjusting the rolling leveling amount of the rolling device based on the amount so that the wedge ratio on the exit side of the rolling mill is equal.

In addition, in order to cope with the demand for plate thickness accuracy that has become increasingly strict in recent years, as disclosed in Japanese Patent Application Laid-Open No. 57-206511, we first measured the difference between the left and right roll gaps in a rough rolling mill. Based on this wedge amount, the rolling leveling amount of the next stand is feedforward controlled so that the wedge amount on the exit side of the next stand is small, and then the camber meter on the entry side of the finishing tandem rolling machine is There is a method in which the initial camber is measured and, based on the measured value, the rolling leveling of the first stand of the finishing tandem rolling mill is operated so that the camber at the leading and trailing ends of the strip becomes zero.

[Problem to be solved by the invention]

Figure 6 shows the relationship between the camber curvature and the wedge ratio ψ, which was obtained through repeated experiments by the inventors, and as is clear from the measurement results, only the rear tension acts on the tip of the strip. Under rolling conditions, the amount of wedge change and the amount of camber change have an approximately one-to-one relationship (proportionality coefficient ξ-1,0
), and under rolling conditions where only the forward tension acts on the rear end, if the rolling reduction is r (-(Enter side plate thickness H - Output side plate thickness h)/Enter side plate thickness H), then Bo1 vs ξ = (1,
)! The relationship is as follows. From this, at the tip, if you change the amount of wedge by adjusting the reduction leveling to control the camber or wedge, the camber will change corresponding to the wedge change rate, and with the same stand, the camber and wedge will change completely. It is understood that they cannot be independently controlled.

In addition, at the rear end, the relationship between the amount of wedge change and the amount of camber change is smaller than in the case of l, so it is understood that the wedge is relatively easy to straighten compared to the front end, but the camber is difficult to straighten. Ru.

Therefore, in the case of the method disclosed in Japanese Patent Publication No. 57-11724, the wedges generated during the rough rolling remain at the same wedge ratio until the exit of the finishing tandem mill, impairing the homogeneity of the strip. Further, in the case where camber occurs at the stage of rough rolling, the control method and effect thereof are unclear in this prior example.

The method disclosed in JP-A-57-206511 is nothing but a method of controlling the camber at the leading and trailing ends of the strip to be small and the wedge in the steady section to be small, so if the wedge is controlled to zero during rough rolling, the rough rolling When the reduction leveling of the first stand of the finishing tandem rolling mill is operated to reduce the camber generated during this rough rolling stage, a wedge remains on the exit side of the rolling mill. become.

Figure 7 and Attached Table 2 show the leveling change amount, wedge amount, and
This shows the results of measuring the change in the amount of camber.In order to overlap rolling passes without causing camber, it is necessary to maintain a constant wedge ratio during rolling.
As illustrated and displayed, the wedge will remain on the exit side of the final N117 stand.

From the above, even if you try to correct the initial camber and initial wedge formed in the rough rolling stage in the first stand of the finishing tandem rolling mill, as in the two preceding examples,
It is clear that if the camber is set to zero, the wedge will remain, and if the wedge is set to zero, the camber will remain.In the above conventional method, at least one of the initial camber and the initial wedge will be inherited until the final stand exit side. I did it,
There was a problem in that it was difficult to eliminate (correct) both of them.

The present invention has been made to solve the above-mentioned conventional problems, and therefore, when a hot rough-rolled strip is finish-rolled in a finishing tandem continuous hot rolling mill, the edges of the strip that occur during the rough-rolling stage are removed. It is an object of the present invention to provide a strip rolling method that can reliably prevent camber and wedge from genetically remaining until the exit side of a final stand.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has the following objective: When a strip is finish rolled in a finishing tandem continuous heat control rolling mill, the amount of camber at the end of the strip on the entry side of the rolling mill is sampling and measuring the wedge amount at predetermined time intervals, performing roll leveling control to reduce the initial wedge by changing the roll leveling amount based on the wedge amount in the front stage stand of the rolling mill, and tracking the strip, In the downstream stand of the rolling mill, the rolling leveling control is performed to reduce the residual camber by changing the rolling leveling amount corresponding to the tracking value of the camber amount on the portion of the strip where the rolling leveling control has been performed. It is structured as follows.

[Effect]

In the present invention, the rolling leveling control for reducing the initial wedge and the rolling leveling control for the initial camber are performed in separate rolling passes. Since the rolling leveling control is performed in the later pass where the amount of residual camber is reduced, it is possible to prevent both the initial wedge and the initial camber from being inherited to the exit side of the final stand of the finishing tandem rolling mill.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, Fl, F2,...F7 are the 1st stand, 2nd stand, 7th stand of the finishing tandem rolling mill, 1 is the rolling roll, 2 is the backup roll,
3 indicates a rolling down device, and 4 indicates a strip. 5 is a camber meter disposed on the entrance side of the tandem rolling mill, 6 is a wedge meter, and 7 is a length measuring needle, and their output signals are supplied to an arithmetic and control unit 8.

In this embodiment, the arithmetic and control device 8 calculates the camber amount which is the output of the camber meter 5, the wedge amount which is the output of the wedge meter 6, and the distance from the tip of the strip 4 which is the output of the length meter 7 at predetermined sampling intervals. At the same time, input the sampling and calculate the required reduction leveling change amount ΔS to zero the wedge amount (initial wedge amount) that has occurred at the tip end (and rear end if necessary) of the strip 4 during rough rolling. and the front stand (in this example, stand 111111 and N
A control command is given to the lowering device 3 of the a2 stand).

Also, in the rear stand (in this example, the 7th stand),
The required leveling change amount ΔS of the rolling down device 3 necessary to control the remaining camber to a predetermined level or less is calculated from the following equation (1) using the above camber amount, and the strip 4
The calculated value above is corrected using the tracking data at a predetermined tie-straw where the wedge-controlled part in the front stand passes through this rear stand.
It is given as a control command to the lowering device 3 of the rear stage stand.

Wedge change amount ΔS - camber amount to be corrected x board width W
×Exit side plate thickness h...(1) Prior to a detailed explanation of the present invention, in order to facilitate understanding of the present invention, we will explain how the initial camber and initial wedge of the strip change as rolling progresses. This will be explained with reference to FIGS. 8 and 9, respectively.

As shown in Fig. 8, the curvature of the initial camber existing at the tip of the strip on the entry side of the finishing tandem rolling mill decreases by a factor of (1-r) with each rolling pass. At the exit side of the tandem rolling mill, the value is very small, close to zero, and can be corrected by a small amount of leveling change in the subsequent pass, and the wedge formed by this leveling change is also very small.

On the other hand, the initial wedge that existed at the tip of the strip on the entry side of the finishing tandem rolling mill becomes as shown in Fig. 9 when the leveling is changed to keep the camber amount constant on the exit side of each stand. The front-stage pass has a large change in the wedge amount, and the rear-stage pass has a small change in the wedge amount.

This is because the difference between the wedge ratio between the input side and the exit side of the rolling machine, which is calculated by dividing the wedge amount by the plate thickness, that is, the change in the wedge ratio corresponds to the change in strain. This is because changes in the wedge greatly affect camber.

Based on the above considerations, the present invention has realized that when the camber amount on the exit side of the finishing tandem rolling mill is set to the same level, the front pass is
Focusing on the fact that the amount of wedge change can be made large, we performed roll-down leveling control to bring the wedge to zero in the first pass, and roll-down leveling control to bring the remaining camber to zero in the second pass. .

FIG. 5 shows the measurement results when the present invention was carried out using the apparatus configuration shown in FIG. 1, and the measurement results are tabulated and shown in Attached Table 1.

However, this is a case where the width W of the strip is 1000 mm, and the distance between the rolling support points is 3150 mm.

In this actual measurement example, initial camber amount: 3X10-'1/m,
For a strip with an initial wedge amount of 1100I1, reduction leveling control was performed in the front stand of the finishing tandem rolling mill to reduce the wedge to zero, and reduction leveling control was performed in the subsequent stand to reduce the residual camber to zero. The changes in leveling change, wedge amount, and camber amount for each stand were measured in this case.

In this example, as is clear from FIG. 1 and Table 1,
With respect to the same portion in the longitudinal direction of the strip 4, a reduction leveling change of about 250 pm was made in the Nal stand, and a reduction leveling change of about 60 am was made in the Nα2 stand. As a result, the wedge amount becomes O on the exit side of the third stand, and is maintained at O in subsequent rolling passes. Regarding the camber, with the change in the leveling amount, a reverse camber with a size of 3×10-'17 m is generated. However, as the rolling passes are repeated, the generated reverse camber rapidly decreases as explained in FIG. 8, and in the final Nα7 stand, the
It became only 3×10-'1/m. The amount of leveling change required to correct this camber is approximately 1 at most.
.mu.m, and the remaining wedge was only about 0.3 .mu.m.

As described above, in this embodiment, the initial wedge correction control is performed in the first pass where the leveling effect is large in response to the wedge change, and the camber correction control is performed in the second pass due to the characteristic that it decreases as the rolling passes are repeated. , the initial wedge, and the initial camber no longer affect the final stand.

The above explanation is about the tip of the strip, but the same applies to the reduction leveling control to eliminate the initial wedge and initial camber at the rear end of the strip, and the required leveling change amount ΔSt for camber correction can be found from equation (2) below. Bye.

Figure 2 shows a wedge meter 6A for measuring the wedge amount on the exit side of the intermediate stand (in this example, the Nt13 stand).
If there is a residual wedge, it is removed at the next stand, and learning is performed to calculate the required leveling change amount for the next material.

In addition, a total of 5A of camber is installed on the exit side of the 7th stand in Figure 3.
and a wedge gauge 6B are installed to actually measure the final actual camber amount and wedge amount to learn how to calculate the required leveling change amount for the next material.

In addition, Fig. 4 shows the intermediate stand (
In this example, a wedge meter 6A is provided to measure the amount of wedge on the exit side of the Ko 3 stand, and the corrections shown in FIGS. 3 and 4 are performed.

〔Effect of the invention〕

As explained above, the present invention performs the rolling leveling control to reduce the initial wedge and the rolling leveling control for the initial camber in separate rolling passes, and the rolling leveling control for the initial wedge is performed in the previous pass where the amount of wedge change can be large. Since the reduction leveling control for the initial camber is performed in the latter pass where the amount of remaining camber is small, it is possible to prevent the initial wedge and initial camber from genetically remaining until the exit side of the final stand.
Yield can be improved compared to conventional methods.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams showing the configuration of a finishing tandem rolling mill in which the present invention is implemented, Figure 5 is a diagram showing measurement results when the present invention is implemented in the embodiment shown in Figure 1 above, Figure 6 is a diagram showing wedge ratio-camber curvature characteristics, Figure 7 is a diagram showing changes in leveling change amount and wedge amount when rolling down leveling control is performed with the camber curvature at each stand set to zero, and Figure 8 9 is a diagram showing the transition of the initial camber as the rolling progresses, and FIG. 9 is a diagram showing the transition of the initial wedge as the rolling progresses. i-i extended roll, 2・-backup roll, 3-・
Reduction device, 4-strip, 5.5A-camber meter,
6.6A, 6B-・Wedge meter, 7-Length meter, 8-・-
Computing device.

Claims (1)

[Claims] When a hot roughly rolled strip is finish rolled in a finishing tandem continuous hot rolling mill, the camber amount and wedge amount at the end of the strip are simultaneously sampled at predetermined sampling intervals on the entry side of the rolling mill. Measured, and at the front stand of the rolling mill,
The roll leveling control is performed to reduce the initial wedge by changing the roll leveling amount based on the wedge amount, and the strip is tracked, and in the subsequent stand of the rolling mill, the part on the strip where the wedge control was performed is performed. On the other hand, a strip rolling method characterized in that a reduction leveling control is performed to reduce residual camber by changing a reduction leveling amount corresponding to the tracking value of the camber amount.