KR100428575B1 - Apparatus for preventing from twisting strip - Google Patents

Abstract

The present invention relates to a hot-rolled sheet twist prevention device for preventing meandering and flying phenomenon by pressing the line and the rear end of the strip by a predetermined fluid pressure between the rolling stands. A rolling equipment having a rolling stand of a rolling control system, comprising: a rolling control system that collectively controls the rolling operation of the rolling equipment and provides rolling equipment and operation information, and receives various information about the rolling equipment and operation from the rolling control system. An anti-twist controller which instructs the injection signal according to the time calculated by calculating the injection start time and the injection time for accurately injecting the fluid in the front and rear ends of the strip, and on / off operation under the control of the anti-twist controller A quick valve providing a fluid having a predetermined pressure and the quick valve under control of the anti-twist controller. A switching valve for switching the path of the provided fluid and first and second spray nozzles installed in the upper middle of the two rolling stands and directed toward the front rolling stand and the rear rolling stand, and according to the switching operation of the switching valve. It consists of a header for injecting the fluid supplied to the first or second injection nozzle.

Description

Hot rolled sheet twist prevention device {APPARATUS FOR PREVENTING FROM TWISTING STRIP}

The present invention relates to a hot rolling facility, and relates to a hot rolled sheet anti-twisting device capable of preventing the twisting phenomenon that may occur at the front and rear ends of the strip during hot rolling.

In the hot rolling process, as shown in FIG. 1, after installing one or more rolling stands 12 for pressing a strip with an upper and lower rolling roll to roll to a predetermined thickness, the roll gaps of the respective rolling stands 12 are small. By passing through the strip 11 by adjusting it to a stationary state, a product of a desired thickness is produced.

At this time, the side guide 13 for guiding the strip 11 to pass through the center of the rolling stand is provided, the tension between each rolling stand 12 for constantly adjusting the tension of the rolled strip (11) An adjusting looper 14 is installed.

However, since tension cannot be applied to the front end and the rear end of the strip 11, the front and rear ends of the strip may collide with the side guides 13, thereby causing a twisting phenomenon in which the strip is folded and rolled. In particular, when the rear end of the strip ends the rolling in the shear rolling stand and the load is lost, after the looper 6 for adjusting the tension between the two rolling stands 12i and 12i-1 is lowered, the next rolling stand is Since it is rolled in, it is rolled up by meandering or flying. In particular, as shown in Figure 2, the rear end of the strip is produced in the shape of the tail fin of the fish, it is more easily twisted.

In this way, if a twist occurs in the strip, the surface of the roll (roll) is scratched, causing a reduction in the quality of the product, of course, because the corresponding roll must be replaced, the productivity is lowered and the life of the roll is shortened.

The present invention has been invented to solve the conventional problems as described above, the object of the hot-rolled sheet twist prevention device to prevent meandering and flying phenomenon by pressing the line, the rear end of the strip by a predetermined fluid pressure between the rolling stand. To provide.

1 is a process diagram schematically showing a general rolling equipment.

2 is a process state diagram for explaining the hot-rolled sheet twist problem in the conventional rolling equipment.

Figure 3 is a block diagram showing a hot-rolled sheet twist prevention device according to the present invention.

Figure 4 is a block diagram showing the configuration of the header and valve in the hot-rolled sheet twist prevention device according to the present invention.

5 is a schematic view showing a spraying state for preventing the twist of the hot rolled sheet according to the present invention.

Figure 6 is a flow chart showing the operation sequence of the hot-rolled sheet twist prevention device according to the present invention.

7a to 7d is a state diagram for comparing the operating conditions of the conventional rolling equipment and the rolling equipment equipped with a hot rolled sheet preventing apparatus according to the present invention.

8 is an explanatory view for explaining the principle of the kink prevention by the injection angle and the injection pressure.

* Explanation of symbols for the main parts of the drawings

11: strip 12i: i-th rolling stand

13 side guide 14 looper

31: rolling control system 32: anti-twist controller

33: quick open valve 34: switching valve

35: injection header 15i: rolling force detection sensor of the i-th stand

16i: Rotation detection sensor of the i stand

As a constitutional means for achieving the above object of the present invention, the apparatus for preventing twisting of a hot rolled sheet according to the present invention is a rolling apparatus having a plurality of rolling stands for rolling a strip sequentially.

A rolling control system that collectively controls the rolling operation of the rolling equipment and provides rolling equipment and operation information;

Provides various information about the rolling equipment and operation from the rolling control system and calculates the starting point and injection time for precisely injecting the fluid in the front and rear ends of the strip, and instructs the injection signal according to the calculated time. With the controller,

Quick valve for providing a fluid of a predetermined pressure by the on / off operation under the control of the anti-twist controller,

A switching valve for switching a path of a fluid provided from the quick valve according to the control of the anti-twist controller;

It is installed in the middle of the two rolling stands, and provided with the first and second spray nozzles toward the front rolling stand and the rear rolling stand, and injects the fluid supplied to the first or second spray nozzle according to the switching operation of the switching valve. It is characterized by consisting of a header.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the hot-rolled sheet twist prevention device according to the present invention.

3 is a process diagram schematically showing a hot rolling facility to which a hot rolled sheet anti-twisting apparatus according to the present invention is applied. The hot rolled sheet anti-twisting apparatus according to the present invention collectively controls the rolling operation of the rolling mill. Rolling control system 31 for providing a and the starting point and the injection time for the injection of the fluid precisely in the front and rear end of the strip by receiving a variety of information about the rolling equipment and operation from the rolling control system 31 An anti-twist controller 32 for instructing the injection signal in accordance with the calculated time calculated, a quick valve 33 for providing a fluid having a predetermined pressure by turning on / off under the control of the anti-twist controller 32; A switching valve 34 for switching the injection direction of the fluid provided from the quick valve 32 according to whether it is the front end or the rear end of the strip; It is made of a soft stand (12i) side and the header (35) for injecting a fluid of a predetermined pressure toward the rear end of rolling stands (12i-1).

In FIG. 3, 12i is a plurality of rolling stands arranged in a line at predetermined intervals along the advancing direction of the strip 11 to roll the strips, and i represents the order of the rolling stands. 15i is a rolling force detection sensor installed in the rolling stand 12i to detect the rolling pressure, 16i is a rotational detection sensor for detecting the rolling roll rotational speed of the rolling stand 12i, and WRi is a corresponding rolling stand. The roll diameter of (12i) is shown.

4 is a view showing in more detail the configuration of the valves 33 and 34 and the header 35 provided in the hot-rolled sheet twist prevention device according to the present invention, the header 35 is 45 degrees in the opposite direction to the strip traveling direction A first spray nozzle 35a facing downward and a second spray nozzle 35b facing 45 degrees downward toward the strip advancing direction are provided, and the switching valve 34 is provided through the quick valve 33. It is connected to selectively provide the applied fluid to the first spray nozzle 35a or the second spray nozzle 35b of the header 5.

6 is a flow chart showing the operation sequence of the hot-rolled sheet twist prevention device according to the present invention, with reference to this will be described the hot-rolled sheet twist prevention operation according to the present invention.

First, the position of the strip must be detected to determine the spraying direction. In step s601 of FIG. 6, it is determined whether the post-rolling stand 12i has started rolling based on the header 35, which corresponds to the corresponding rolling stand 12i. Is made by checking whether the rolling force detection sensor 15i mounted on the) is turned on.

At this time, if the strip is not stuck to the post-rolling stand 12i, that is, if the rolling force detection sensor 15i is off, the front end of the strip has not yet arrived. The selector valve 33 is switched so as to extend to the single injection nozzle 35a side.

Next, in step S603, it is determined whether the strip has passed through the shear rolled stand 12i-2, that is, the rolling force detection sensor 15i-2 installed in the shear rolled stand 12i-2 is turned on. If so, the process proceeds to step 604, the side guide 13i provided at the inlet of the post rolling stand 12i is completely opened, and the process proceeds to step 605 to store the current time at t1. Then, at step 606, the traveling speed Vi-1 of the strip by the shear rolling stand 12i-1 is calculated, which is calculated as in Equation 1 below.

In the above, WRi is the roll diameter of the i-th rolling stand and fi is the rotation speed of the i-th rolling stand, as described above, which is detected by the rotation speed detection sensor 16i.

Here, as shown in FIG. 3, the fluid spray length required to impart a predetermined tension to prevent twisting of the hot rolled sheet is the front end portion of the hot rolled sheet, where the strip is located at the rear end of the header 35. Lts until it is bitten by 12i), and when it is the rear end of a hot rolled sheet, it is represented by Lbs which is the distance from the shear rolling stand 12i-1 to the header 35. FIG.

Therefore, in step S607, the injection start time Ttt for injecting the tip of the strip is calculated, which is expressed by Equation 2 below.

From above. L _i-2 is the distance between the shear rolled stand 12i-2 and the shear rolled stand 12i-1, V _i-2 is the rotational speed of the shear rolled stand 12i-2, and V _i-1 Is the rotational speed of the shear rolling stand 12i-1, Lbs is the distance between the header 35 and the shear rolling stand 12i-1, and α is the response time of the quick valve 34 depending on the application of the control signal.

Further, in step s608, the injection time Stt to the tip is calculated, which is calculated as Equation 3 since the time taken for the tip of the strip to come from the shear rolling stand 12i-1 to the header 35. .

As such, when the injection time and the injection time are calculated, at the time t1 at which the shear shearing stand 12i-2 starts operation in steps 609 and 610, the time passes by the calculated injection time Ttt. When the injection time is determined, and when the injection time, the quick valve 34 is opened during the calculated injection time (Stt) in step S611 to inject the fluid to the front end of the strip, and after completion of injection, open in step 612 The side guide 13i which has been made is operated again.

The injection to the leading end of the strip has been described above, and the injection to the rear end of the strip will now be described.

In the step s601, if the post-rolling stand 12i is in the rolling operation state, since the front end of the strip has already passed, the process proceeds to step 613, where the switching valve 33 is directed toward the post-rolling stand 12i. The switching operation is performed to supply the fluid to the two-jet nozzle 35b.

Then, it is judged by checking whether the front end rolling stand 12i-2 has passed the rear end of the strip and whether the rolling force detection sensor 15i-2 is turned off.

Then, if the rolling force detection sensor 15i-2 is turned off, at step 615, the side guide 13i is opened, and at step s616 the rear end of the strip is pulled out of the shear rolled stand 12i-2. For example, the current time is stored at t1.

Then, in step s617, as described above, using Equation 1, the moving speed Vi-1 of the rear end of the strip is calculated.

In step S618 and step S619, the injection start time Ttb and the injection time Stb for the rear end of the strip are calculated as in Equations 4 and 5, respectively.

In the above, Lbs is the distance from the shear rolling stand i-1 to the injection header 35 as described above.

As described above, when the injection time and the injection time for the rear end of the strip are calculated, in step S620 and 621, it is determined whether the injection time has been reached by checking the current time, and when the injection time is reached, the calculated injection time ( The quick valve 34 is opened as much as Stb) to inject a fluid having a predetermined pressure to the rear end of the strip.

The above operation is repeated until the rolling operation is stopped to inject fluid of a predetermined pressure so that twisting does not occur on the front and rear ends of all strips.

Figure 7a schematically shows the rolling situation for the leading end of the strip in the conventional rolling equipment, as shown, it can be seen that the flying occurs at the leading end of the strip. In comparison, FIG. 7B shows a process of the rolling equipment according to the present invention, in which a fluid of a predetermined pressure is injected from the header 7 with respect to the strip end portion, thereby preventing flying.

Figure 7c shows the working state in the conventional rolling equipment, it can be seen that the meandering or flying occurs while the tension is lost at the rear end of the strip, as shown in Figure 7d showing a working state of the rear end of the strip according to the present invention. In the present invention, it can be seen that the injection header 35 injects a fluid of a predetermined pressure from the time point when the tension is lost at the rear end of the strip to prevent the flying of the rear end of the strip.

8 (a) is an explanatory diagram for setting the injection angle in the injection header 35, and when it is the same as in FIG. 8 (a), as shown in Equation 6 and Equation 7 below, anti-twist The force for is related to the force Fj that the strip is intended to twist, and that Fj is the smaller the spray angle, but at the leading end, the fluid is injected in the direction of the strip and at the trailing end the fluid is the opposite of the strip. It can be seen that the twist in the direction to prevent the twisting of the strip.

And, as in the relationship between the injection angle and the force shown in (b) of FIG. 8, since the Fj value should be 70% or more when the injection angle is 0 degrees, the injection angle is between 5 degrees and 45 degrees. In consideration of Fi and Fj, the spray angle is found to be 30 degrees.

In addition, the high temperature yield strength of the strip rolled at the hot rolling temperature is about 0.5 ~ 20 kgf / mm2, and if it is more than about 2.0 kgf / mm2 regardless of the material, the anti-twist effect is large, considering the pressure and flow rate of the fluid Figure 8 From the impingement pressure with respect to the nozzle height of (c), the height of the nozzle can be set such that the fluid is injected at a pressure of 2.0 kgf / mm 2, which can prevent twisting at a predetermined injection angle.

The present invention, as described above, by spraying a fluid of a predetermined pressure to the front end and the rear end of the strip of tension loss, there is an excellent effect that can prevent the twist at the front end and the rear end of the strip, as a result, the quality of the product This is an excellent effect to improve the productivity, and to improve the productivity by extending the life of the roll.

Claims (2)

In the apparatus for preventing twisting of a hot rolled sheet of a rolling equipment having a plurality of rolling stands for rolling strips sequentially, A rolling control system that collectively controls the rolling operation of the rolling equipment and provides rolling equipment and operation information; Provides various information about the rolling equipment and operation from the rolling control system and calculates the starting point and injection time for precisely injecting the fluid in the front and rear ends of the strip, and instructs the injection signal according to the calculated time. With the controller, Quick valve for providing a fluid of a predetermined pressure by the on / off operation under the control of the anti-twist controller, A switching valve for switching a path of a fluid provided from the quick valve according to the control of the anti-twist controller; It is installed in the upper middle of the two rolling stands, and has first and second spray nozzles directed toward the front rolling stand 12i and the rear rolling stand 12i-1, and according to the switching operation of the switching valve, the first or second A device for preventing twist of a hot rolled sheet, characterized in that the header is configured to inject the fluid supplied to the injection nozzle. According to claim 1, wherein the anti-twist controller Determining the injection direction by detecting the positions of the front and rear ends of the strip to be rolled; Calculating each injection time and injection time according to the plate speed of the front end or the rear end of the strip; Preventing twisting device of the hot rolled sheet, characterized in that the control operation by the step of preventing the twisting of the front end / rear end by opening the quick valve during the time calculated at the injection time calculated above.