KR20090065664A - Method for the meandering control in strip-casting process - Google Patents

Abstract

A method for meandering control in a twin roll strip-casting apparatus is provided to remove instability of strip resulting from temperature and thickness variation by implementing correction control of the rolling mill and two pinch rolls. A method for meandering control in a twin roll strip-casting apparatus comprises a difference measuring step of measuring the difference between right and left thicknesses of a strip(1) before and after a rolling mill(2,3,4,5), a positioning step of measuring the location of the strip before and after the rolling mill, a thickness control step of PID(Proportional Integral Derivative)-controlling to make the thickness differences before and after the rolling mill equal, and a temperature difference control step of compensating the thickness control to make the advancing direction of the strip according to the strip location before and after the rolling mill the same as the discharge path line.

Description

Meandering control method of twin roll sheet metal fabrication apparatus {Method for the meandering control in strip-casting process}

The present invention relates to a meandering control method of a twin-roll thin sheet manufacturing apparatus, and in particular, meandering caused by the direction of the sheet due to the temperature deviation even by the thickness control on the left and right sides of the rolling mill does not coincide with the discharge pass line. It relates to a meander control method of a twin-roll thin plate manufacturing apparatus that can improve the casting stability in consideration.

In general, in the twin roll type sheet manufacturing process, the factors that have an unstable effect on the sheet flowability of the sheet is divided into left and right inequality mass balance and left and right sheet temperature deviation.

Factors affecting left and right inequality mass balance are the roll gap deviations of the rolling mill and the thickness deviations of the left and right thin plates. Various left and right unbalanced mass balance has been proposed to adjust the left and right roll gap of the rolling mill to match the left and right thickness deviation of the sheet at the entry and exit side.

Among these methods, the meandering prevention rolling method considering the roll deformation according to the rolling load solves the instability of the left and right scalpel balance caused by the roll deformation.

In addition, the meandering control method by setting the finishing mill stand level is a control method which resets the left and right balance of the rolling mill roll using the profile data obtained when cutting into a 20 ton coil.

In addition, a meander control method for pinch rolls and a pinch roll meander control method in a twin coiler of a strip casting continuous rolling process have been proposed for meandering control in a twin roll sheet metal manufacturing process.

On the other hand, even if the thickness of the left and right thin plates is the same due to the left and right thin plate temperature deviations, which are factors of the plateability instability of the other thin plates, the force for pressing the thin plates by the pinch roll and the rolling mill left and right cylinders varies from left to right. The thin plate produced by the cylinder deviation generates meandering.

However, the conventional meander control method in the twin roll type thin plate manufacturing process has a problem of uncertainty in casting stability because it does not consider the meandering caused by the left and right temperature variations of the thin plate.

The present invention has been proposed to solve the above problems, due to the temperature deviation of the thin plate as well as the thickness deviation of the thin plate can be stably controlled the meandering due to the progress direction of the thin plate does not match the discharge pass line An object of the present invention is to provide a meandering control method for a twin roll sheet metal fabrication apparatus.

The present invention for achieving the above object is a deviation measuring step of measuring the left and right thickness deviation of the thin plate at the front and rear end of the rolling mill; A position measuring step of measuring the position of the thin plate at the front and rear ends of the rolling mill; A thickness control step of PID control such that the sheet thickness deviations of the front and rear ends of the rolling mill are equal to each other; And a temperature deviation control step of compensating for the thickness control so that the traveling direction of the thin plate according to the position of the thin plate at the front end and the rear end of the rolling mill is the same as the discharge pass line.

Preferably in the temperature deviation control step, calculating the traveling angle of the thin plate according to the thin plate position of the front end and the rear end of the rolling mill; A direction control step of PID control such that the traveling angle of the thin plate becomes "0"; It may include.

The present invention may further include a pinch roll control step of controlling the two pinch rolls so that the sheet position between the first pinch roll and the second pinch roll in front of the rolling mill is equal to the dispensing pass line.

Preferably in the pinch roll control step, the second position measuring step of measuring the position of the thin plate between the first pinch roll and the second pinch roll; A position control step of PID control such that the second position measurement value follows a target sheet position value; And a roll gap control step of adding or subtracting the control result to the left and right pressure set values of the pinch rolls and PID controlling the roll gaps of the pinch rolls.

Preferably, in the position control step, the coefficient value of the PID control may be set to be proportional to the ratio of the distance between the rolling mill and the first pinch roll and the distance between the rolling mill and the second pinch roll.

The meandering control method of the twin-roll type thin sheet manufacturing apparatus according to the present invention includes the rolling mill and its front end so that the traveling direction of the thin plate according to the position of the front and rear ends of the rolling mill is the same as the discharge pass line during roll gap control of the rolling mill. By performing compensation control for two pinch rolls, it is possible to prevent casting instability of the sheet due to the uncertainty of the thickness variation and the temperature variation of the sheet, thereby improving casting stability.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram for a meander control method of a twin-roll thin plate manufacturing apparatus according to the present invention.

The rolling mill for securing the material quality of the thin plate 1 manufactured in the casting machine of the twin-roll type thin plate manufacturing apparatus is composed of four stage rolls, and the rolling mill backup roll 2 and the rolling mill working roll 3 are disposed up and down. At the front end of the rolling mill, a first pinch roll 4 and a second pinch roll 5 are arranged to adjust the sheet-to-wall properties of the thin plate 1 to be manufactured.

The rolling mill working roll 3, the first pinch roll 4, and the second pinch roll 5 are separate left and right cylinders for individually controlling the left and right roll gaps, that is, the first pinch roll driving cylinders 12, 12 ′. ), Second pinch roll drive cylinders 13 and 13 'and rolling mill drive cylinders 14 and 14'.

In order to measure the stable plateability of the thin plate 1 to be manufactured, the position detectors 6, 7, and 8 which measure the position of the thin plate 1 to be manufactured are located at a dispensing pass line. It is arrange | positioned between the pinch roll 4 and the 2nd pinch roll 5, and the front and rear ends of the rolling mill walking roll 3, respectively. Here, the values 9, 10, and 11 measured by the respective position detectors 6, 7, and 8 are expressed as thin plate meandering amounts at the respective positions.

In order to measure the thickness of the left and right sides of the thin plate 1 to be manufactured, the side plate thickness gauge 15 and the outgoing sheet thickness gauge 16 are disposed at front and rear ends of the rolling mill.

Each roll driven by each cylinder is provided with a cylinder position measuring device (20, 21, 22) for measuring the gap between the upper and lower rolls and the roll, pressure measuring instruments (17, 18) for measuring the pressing force pressed by each cylinder 19) are arranged.

In the casting machine of the twin-roll thin plate manufacturing apparatus configured as described above, the interface structure for meandering control is as follows.

FIG. 2 is a diagram illustrating an interface for meandering control of FIG. 1.

The meandering control unit 23 is composed of a command signal transmitter 24 for transmitting a command for driving each cylinder, and a feedback signal input unit 25 into which data measured from each measuring instrument is input.

The command signal transmitter 24 sends the operation command to the first pinch roll drive cylinder 12, the second pinch roll drive cylinder 13 and the rolling mill drive cylinder 14 according to the control result by the meandering control method according to the present invention. send.

In the feedback signal input unit 25, the thickness of the thin plate is input from the side plate thickness gauge 15 and the exit plate thickness gauge 16, and between the first pinch roll 4 and the second pinch roll 5 and the rolling mill walking. The position of the thin plate is input from the position detectors 6, 7, 8 arranged at the front and rear ends of the roll 3. In addition, the feedback signal input unit 25 receives the pressure reduction force of the cylinder from the pressure measuring devices (17, 18, 19) disposed in each cylinder, and the roll gap of the cylinder from the cylinder position measuring devices (20, 21, 22) is input. .

According to the present invention, the meandering due to the left and right thickness deviations of the thin plate and the meandering due to the left and right temperature deviations are simultaneously controlled. For the meandering due to the left and right thickness deviations, two rolling mill shear pinch rolls and left and right roll gaps of the rolling mill are set. The value is controlled, and for meandering due to left and right temperature deviations, the traveling angle of the sheet is calculated at the front and rear ends of the rolling mill, and the left and right roll gap set values of the rolling mill are controlled so that the angle is zero.

That is, the meandering control method of the twin-roll type sheet manufacturing apparatus according to the embodiment of the present invention is a thin plate (in the sheet thickness measuring device 15 and the exit sheet thickness measuring device 16 arranged at the front and rear ends of the rolling mill working roll 3). Deviation measuring step of measuring the left and right thickness deviation of 1), and the position detector (6, 7) disposed between the first pinch roll (4) and the second pinch roll (5) and the front and rear ends of the rolling mill working roll (3) A position measuring step of measuring the position of the thin plate 1 at 8, and a thickness control step of PID control by the rolling mill thickness controller 310 such that the thickness deviations of the thin plate 1 at the front and rear ends of the rolling mill are equal to each other; Temperature deviation control to compensate for the thickness control by the advancing direction calculator 320 and the PID controller 330 so that the advancing direction of the thin plate according to the position of the thin plate 1 at the front end and the rear end of the rolling mill is the same as the discharge pass line. It consists of.

Hereinafter, the meander control method of the twin-roll thin plate manufacturing apparatus according to an embodiment of the present invention with reference to FIGS. 3 to 4 in more detail.

3 is a block diagram of a rolling mill meander control method of the meander control method of the twin-roll thin plate manufacturing apparatus according to an embodiment of the present invention.

Temperature deviation control step of the meander control method of the twin-roll thin plate manufacturing apparatus according to an embodiment of the present invention is to calculate the traveling angle of the thin plate according to the position of the thin plate (1) at the front and rear end of the rolling mill, and the progress of the thin plate (1) And a direction control step of PID control such that the angle is "0".

Here, thickness control for controlling the thickness of the thin plate 1 to be manufactured to follow a predetermined target value is preceded by the rolling mill thickness controller 310.

That is, when the side thickness value and exit side thickness value of the thin plate 1 and the left and right side pressure reduction force value of the rolling mill walking roll 3 are input into the mill thickness controller 310, the left and right thickness deviation of the exit side thin plate 1 is entered into the side plate ( The left and right roll gaps of the rolling mill working rolls 3 are controlled to be equal to the left and right thickness deviations of 1) to keep the left and right mass balances of the rolling mills equal. At this time, the rolling mill thickness controller 310 calculates the left and right roll gap target values of the rolling mill walking roll 3.

In the left and right equilibrium conditions of the rolling mill, when the thin plate 1 position values 10 and 11 before and after the rolling mill walking roll 3 are input to the traveling direction calculator 320, the thin plate 1 at each position is moved in the traveling direction. The angle is calculated. Here, when the calculation result is not "0", that is, when the direction of the thin plate 1 which proceeds even in the left and right equilibrium conditions of the rolling mill as described above does not become parallel to the dis-most pass line, the thin plate 1 Due to the left and right temperature deviation of

Accordingly, the PID controller 330 controls the PID so that the calculated traveling direction angle of the thin plate 1 is "0", that is, the traveling direction of the thin plate 1 is horizontal with the discharge pass line.

Next, in order to simultaneously control the meandering due to the left and right equilibrium condition of the rolling mill and the left and right temperature variations of the thin plate 1, the result of the PID controller 320 is the rolling mill working roll 3 which is a result of the rolling mill thickness controller 310. Is added to and subtracted from the left and right roll gap target values.

Then, the current roll gap measured from the cylinder position measuring machine 22 of the rolling mill working roll 3 is PID controlled by the PID controller 340 and 350 to follow the target value, and according to the result, the rolling mill driving cylinders 14 and 14 '. By controlling, the meandering control according to the thickness deviation and the temperature deviation of the thin plate 1 can be simultaneously performed.

Figure 4 is a block diagram for pinch roll meander control method of the meander control method of the twin-roll thin plate manufacturing apparatus according to an embodiment of the present invention.

The pinch roll control step of the meandering control method of the twin-roll type thin sheet manufacturing apparatus according to the embodiment of the present invention is a thin plate 1 between the first pinch roll 4 and the second pinch roll 5 of the rolling mill working roll 3. The two pinch rolls 4 and 5 are controlled such that the position is the same as the discharge pass line, which means that the position detector 6 disposed between the first pinch roll 4 and the second pinch roll 5 A second position measuring step of measuring the position of the thin plate 1, and a position control step of PID control such that the second position measuring value 9 measured by the position detector 6 follows the target thin plate position value; And a roll gap control step of subtracting the control result to the left and right pressure set values of the pinch rolls 4 and 5 and PID control of the roll gaps of the pinch rolls 4 and 5.

As shown in FIG. 4, the meandering control for the first pinch roll 4 and the second pinch roll 5 proceeds in a similar manner, firstly by the PID controller 410 for the first pinch roll 4. And PID control so that the thin-plate 1 positional value 9 between and 2nd pinch roll 5 may become a target thin-plate positional value.

Here, the reason for feeding back the same thin plate 1 position value 9 for the control of the first pinch roll 4 and the second pinch roll 5 is the first pinch roll 4 and the second pinch roll 5. This is to prevent the twisting of the thin plate 1 to be produced between).

At this time, the PID control 410 is set to be proportional to the ratio of the distance between the rolling mill walking roll 3 and the first pinch roll 4 and the distance between the rolling mill walking roll 3 and the second pinch roll 5. To set the counting value therein.

The output of the PID controller 410 is added to or subtracted from the pressure set value of the pinch rolls 4 and 5, which is initially set by the left and right pressure variable values of the pinch rolls 4 and 5, and the pinch rolls 4 and 5 The left and right pressure setting values of are to be symmetrical on the pinch rolls 4 and 5.

The PID controllers 420 and 430 are configured such that the left and right pressure values of the pinch rolls 4 and 5 measured by the pressure gauges 17 and 18 follow the left and right pressure set values of the pinch rolls 4 and 5 set as described above. The control unit outputs the left and right roll gap setting values of the pinch rolls 4 and 5.

Finally, the PID controller 440, 450 controls the PID such that the left and right roll gap measurement values of the pinch rolls 4, 5 measured by the cylinder position measuring devices 20, 21 follow the roll gap setting value which is the output of the PID controller 420,430. By controlling the first pinch roll drive cylinders 12 and 12 'and the second pinch roll drive cylinders 13 and 13' according to the result, the sheet flowability due to the uncertainty of the thickness deviation and the temperature deviation of the sheet Instability can be prevented to improve casting stability.

1 is a block diagram for a meandering control method of a twin-roll thin plate manufacturing apparatus according to the present invention.

2 is a block diagram of an interface for meandering control of FIG.

Figure 3 is a block diagram for the rolling mill meander control method of the meander control method of the twin-roll sheet production apparatus according to an embodiment of the present invention.

Figure 4 is a block diagram for pinch roll meander control method of the meander control method of the twin-roll thin plate manufacturing apparatus according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1: thin sheet 2: rolling mill backup roll

3: rolling mill working roll 4: first pinch roll

5: second pinch roll 6, 7, 8: position detector

12: first pinch roll drive cylinder 13: second pinch roll drive cylinder

14 rolling mill drive cylinder 15 side plate thickness gauge

16: Outgoing sheet thickness measuring instrument 17, 18, 19: Pressure measuring instrument

20, 21, 22: cylinder position measuring instrument 23: control unit for meandering control

24: command signal transmitter 25: feedback signal input

Claims (5)

A deviation measuring step of measuring left and right thickness deviations of the thin plates at the front and rear ends of the rolling mill; A position measuring step of measuring the position of the thin plate at the front and rear ends of the rolling mill; A thickness control step of PID control such that the sheet thickness deviations of the front and rear ends of the rolling mill are equal to each other; And a temperature deviation control step of compensating for the thickness control so that the traveling direction of the thin plate according to the position of the thin plate at the front end and the rear end of the rolling mill is the same as the discharge pass line. Meander control method. The method of claim 1, The temperature deviation control step,  Calculating an advancing angle of the sheet according to the sheet position of the front and rear ends of the rolling mill; A direction control step of PID control such that the traveling angle of the thin plate becomes "0"; Meander control method of a bi-roll type thin sheet manufacturing apparatus comprising a. The method of claim 1, And a pinch roll control step of controlling the two pinch rolls such that the sheet position between the first pinch roll and the second pinch roll in front of the rolling mill is equal to the discharge pass line. Meander control method of sheet metal manufacturing apparatus. The method of claim 3, wherein The pinch roll control step, A second position measuring step of measuring a sheet position between the first pinch roll and the second pinch roll; A position control step of PID control such that the second position measurement value follows a target sheet position value; And a roll gap control step of adding or subtracting the control result to the left and right pressure set values of the pinch rolls and PID control of the roll gaps of the pinch rolls. The method of claim 4, wherein Wherein said position control step is set such that the coefficient value of said PID control is proportional to the ratio of the distance between said rolling mill and said first pinch roll and the distance between said rolling mill and said second pinch roll. Meander control method of manufacturing apparatus.

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