JPH01181916A - Method for controlling outlet-side tension in continuous cold rolling mill - Google Patents

Abstract

PURPOSE:To prevent quick reduction of a forward tension by holding the forward tension of a backward strip by a pinch roll at the same time with breaking the strip and holding the forward tension of the backward strip by a take-up machine after the strip is wound round a take-up machine. CONSTITUTION:After the forward strip is cut off, the pinch roll 6 is brought into contact with the strip. At this time, a torque command value gives a torque limiting value 16 nearly equal to a mechanical loss of an electric motor 7 not to disturb tension of the strip S. When the strip S is cut off, the torque command value 14 gives the torque limiting value 16 as generating torque of the pinch roll 6 shows a value corresponding to the setting of the forward tension of the desired strip or 100%. By this forward tension of the backward strip right after the strip is cut off can be prevented from reducing. Further, when the backward strip is rolled on the take-up machine 3, the torque limiting value 16 is lowered, accordingly, the torque of the roll 6 is lapped on the torque of the take-up machine 3. The roll 6 is opened soon after that.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to the tension at the exit side of a continuous cold rolling mill that has a shearing machine and a winding machine and cuts and winds a strip during rolling. The present invention relates to a method for preventing fluctuations in .

<Prior art> Generally, as shown in FIG. 3, a winder 3 is installed on the exit side of a cold rolling mill 1, and the rolled strip S is wound up by this winder 3. Be made into a coil.

The method of winding the tip of the strip S around the winder 3 is -
In i, the strip S is guided by the feed belt trapper 2,
The strip S is wound at a rotational circumferential speed of the winder 3 that is approximately 10% higher than the feeding speed of the strip S.

When winding the strip S around the winder 3, the moment the tip of the strip S is tightly wound around the winder 3, the rotational inertia of the winder 3 is released, causing the strip S to receive excessive energy. Tension acts.

Furthermore, in continuous cold rolling mills, before the above winding,
There is an operation to separate the leading strip and the trailing strip by shearing 1!4 between runs, and the moment the leading strip is separated, the forward tension of the trailing strip decreases rapidly. This decrease in front tension during separation and the above-mentioned excessive tension during winding were the causes of strip-off gauge (out of thickness). Figure 4 shows the fluctuation state of the front tension acting on the trailing strip S at the initial stage of winding the strip S onto the winder 3. From the time t□ when the leading strip is cut off, the front tension changes. Rapidly decreasing, trailing strip winding point 1. It can be seen that the forward tension increases rapidly. This increase in tension is as large as 2 to 3 Ton compared to the tension setting of 2 Ton.

<Problems to be Solved by the Invention> As a countermeasure to this problem, Japanese Patent Application Laid-Open No. 62-89512 proposes a cold rolling mill outlet facility, but this facility does not allow strip wrapping to occur at times. This method only prevents excessive tension, and cannot prevent a decrease in tension when the strip is separated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling the tension on the exit side of a continuous cold rolling mill, which can prevent the sudden drop in tension of a strip during strip cutting as described above.

<Means for Solving the Problems> The present invention solves the problem of fluctuations in tension on the exit side of a continuous cold rolling mill that has a shearing machine and a winder on the exit side, and cuts and winds the strip during rolling. In this method, a tension control device equipped with pinch rolls is provided between the final stand of a continuous cold rolling mill and the shearing machine, and the pinch rolls apply a predetermined torque at the same time as the strip is cut. The front tension of the trailing strip is maintained, and after the leading end of the trailing strip is wound around the winder, the front tension of the trailing strip is maintained by the winder.

<Function> At the same time as the strip is cut, the forward tension of the trailing strip is maintained by a pinch roll that applies a predetermined torque, and after the leading edge of the trailing strip is wound around the winder, the trailing strip is wound by the winder. By maintaining forward tension in the strip,
It is possible to prevent a sudden drop in the front tension of the trailing strip when cutting the strip.

<Example> FIG. 1 shows an example of the apparatus used to carry out the present invention, and in the figure, 1 is the final stand of a continuous cold rolling mill;
2 is a belt wrapper, 3 is a winder, 4 is a shearer, and 5 is a tension control device provided between the final stand 1 and the shearer 4.

Next, the tension control device 5 will be explained. Reference numeral 6 denotes a pinch roll, which maintains the forward tension of the rear strip S when cutting the leading strip. Note that instead of the pinch roll 6, a prydle roll or a combination of a pinch roll and a prydle may be used. 7 is an electric motor that drives the pinch roll 6. The torque control device for electric @7 will be explained.

A torque command value 14 is output from the speed control device 11 in response to a speed command value 15 output from the speed master device 12 . In addition, the torque limit bag RIO has this torque command value 14
can be dynamically restricted. This torque command value limit can be set as an arbitrary torque limit value 16 by the speed master device 12.

Then, the torque command value 13 subjected to the torque limit is outputted to the torque control device 9 through the torque limiting device (RIMICU) 10, and the torque control device 9 controls the Cyrisk power supply device 8 to perform torque control of the electric motor 7.

Note that the torque control device 9 may be a current control device when the electric motor 7 is a DC motor.

In addition, on the exit side of the final stand 1, there is a
It is desirable to provide a buffer 17 to prevent excessive tension that occurs when winding the No. 512 strip.

FIG. 2 shows the power applied to the drive electric power @ 7 of the pinch roll 6 from before the leading strip is cut off to when the trailing strip is wound around the tension reel when the method of the present invention is carried out using the apparatus shown in FIG. 1. An example of the torque limit value 16 is shown.

First, before cutting off the preceding strip, the pinch roll 6 is brought into contact with the strip at T1. At this time, in order to prevent tension disturbance of the strip S, the torque command value 12 is
! A torque limit value of 15, which is about the mechanical loss of 6%, is given, and in the case of the embodiment, a torque limit value of 15 of 5% is given. In this state, the pinch roll 6 exhibits behavior similar to an idle roll.

Next, at time T2 when the strip is separated, the torque limit value 16 is set to 100%, which is the value in which the torque generated by the pinch roll 6 corresponds to the target front tension setting of the strip.
A torque command value of 12 is output. It goes without saying that T2 takes delay into account.

Thereby, it is possible to prevent a decrease in the forward tension of the trailing strip immediately after the strip is separated.

Furthermore, the time T3 when the trailing strip is wound around the winder 3
The torque limit value 16 is lowered to 5%, so that the torque of the pinch roll 6 is not superimposed on the torque of the winder 3. And pinch roll 6 immediately after that T4
It will be released in

Note that the above-mentioned torque limit value and the timing of switching the torque are calculated based on the size and material of the strip in the speed main bag W 12, and tracking of the leading end of the trailing strip.

<Effects of the Invention> As described above, the present invention can prevent the tension of the strip from decreasing when the strip is separated, thereby reliably preventing the occurrence of strip off gauge, and making it possible to manufacture excellent products without variation in plate thickness. It has excellent effects such as being able to achieve a significant improvement in yield.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the apparatus used to carry out the present invention, Fig. 2 is a graph showing the torque limit value of one embodiment of the present invention, and Fig. 3 is a conventional continuous cold rolling method. FIG. 4, which is an explanatory diagram of the exit side equipment of the machine, is a graph showing changes in strip tension that occur when the strip is wound. 1... Final stand of continuous cold rolling mill, 2... Belt wrapper, 3... Winder, 4... Shearing machine,
5... Tension control device, 6... Pinch roll, 7... Electric motor, 8... Cyrisk power supply device, 9... Torque control device, 10... Torque limiting device, 11... Speed Control device, 12... Speed main device, 13... Torque limited torque command value, 14.
...Torque command value, 15...Speed command value, 16.
...Torque limit value, S...Strip. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 2 Figure 3 Figure 4 Time

Claims (1)

[Claims] A continuous cold rolling mill that has a shearing machine and a winder on the exit side and that cuts and winds the strip during rolling to prevent fluctuations in tension on the exit side of the continuous cold rolling mill. A tension control device equipped with a pinch roll is provided between the final stand of the shearing machine and the shearing machine, and the front tension of the trailing strip is maintained by the pinch roll, which applies a predetermined torque at the same time as the strip is cut, and the leading edge of the trailing strip is 1. A method for controlling exit side tension of a continuous cold rolling mill, characterized in that after the strip is wound around the winder, the forward tension of the trailing strip is maintained by the winder.