KR20030054636A - Improvement of massflow balance at hot strip mill and its method - Google Patents

Abstract

PURPOSE: An apparatus and a method for improving threadability of strip in hot finish rolling are provided to improve quality accuracy of hot rolled strip, particularly reduce width defect of the front part of the strip by improving accuracy of unit tension setup value between rear stands in hot finish rolling. CONSTITUTION: The apparatus comprises a width measuring unit(20) for judging metal-in of the rolled strip(2) from width detector(5) between stands (F4-F7) and measuring actual width values of the rolled strip(2); a width change judging unit(30) for judging whether or not deviation of the actual widths and reference width is within the range of allowable width change coefficient by comparing actual widths outputted from the width measuring unit with size of a reference width read from SCC (supervisory control computer) setting unit(10); an excessive width judging unit(40) for judging whether or not deviation of the actual widths and reference width is an excessive width deviated from the range of allowable width change coefficient by comparing actual widths outputted from the width measuring unit with size of a reference width read from SCC setting unit; a short width judging unit(50) for judging whether or not deviation of the actual widths and reference width is a short width deviated from the range of allowable width change coefficient by comparing actual widths outputted from the width measuring unit with size of a reference width read from SCC setting unit; a tension compensation gain operation unit(60) for operating compensation gain to compensate tension value set up in the SCC setting unit(10) according to signals outputted from one of the respective judging units; and a compensated tension set value operation unit(70) for outputting a compensated tension set value calculated according to the compensation gain inputted from the tension compensation gain operation unit into a unit for controlling operation of looper so that tension between the stands (F4-F7) is controlled.

Description

Hot filament stripping improving device and method {Improvement of massflow balance at hot strip mill and its method}

The present invention relates to an apparatus and a method for improving hot finishing rolling property which can reduce the degree of quality of a rolled plate, in particular, a tip width defect, etc. by improving the degree of unit tension set between the rear end stands in hot finishing rolling.

1 is a configuration diagram schematically showing the structure of a conventional hot rolling mill. As shown in FIG. 1, the looper located between each adjacent finishing roll 1 consists of a looper roll 4 and a looper arm 3, and serves to keep the tension of the rolled plate 2 constant. .

Generally, the looper roll 4 has a load cell (not shown), which controls the looper angle to reduce the error between the tension of the rolled plate 2 and the target tension measured by the load sensor. .

However, the load sensor installed in the looper roll 4 is subjected to a large pressure by the rolling plate 2 and the installation conditions are poor, so in most hot rolling mills, the tension of the strip is controlled using the looper angle. First, a looper angle is detected and fed back to a looper drive system, that is, a looper motor that rotates the looper arm 3, so that the detected looper angle is adjusted to a target angle. In addition, the detected looper angle calculates the target speed of the main motor through the looper controller and is input to the main motor to control the rotational speed of the rolling roll 1 by adjusting the rotational speed of the main motor.

At this time, the looper drive system moves according to the output of the looper current controller that calculates the target current so that the looper maintains the desired target angle. The looper current controller calculates a target current of the looper drive system according to the target tension, target thickness, and target width of the rolled plate applied from the supervisory control computer (SCC).

Conventional tension target setting method is calculated through the target tension setting model using the set value of the looper angle, thickness, width, etc., but it is difficult to set the target tension because the accuracy of the formula model to determine the target value of tension is falling. The target value of the looper current has a value different from that of the performance value, making it difficult to control the looper. Therefore, in order to improve the quality of the rolling plate by setting the target value of the looper current according to the actual tension, it is necessary to set the tension target value and a technique for compensating the set value.

Therefore, conventionally, 1) Japanese Patent Application Publication No. 特 開平 9-300010, 2) Japanese Patent Application Publication No. 特 開平 10-225710, 3) Japanese Patent Application Publication No. 2000-326005, 4) Japanese Patent Application Publication 特 開平 10- 263648, 5) In the hot finishing rolling of Japanese patent application 特 開平 09-248609 et al., Tip width deflection prevention and tip tension control techniques have been proposed.

However, in the above-described prior arts, 1) is the same in terms of calculating and controlling the tension of the tip portion, but the influence coefficients of the front tension and the rear tension on the load and the torque are calculated by the method of tension estimation, and the front and rear directions are used. Although it is characteristic that the tension is calculated, it is difficult to obtain the coefficient of influence on load and torque because it is difficult to consider various disturbance conditions in various rolling conditions, and in the prior arts 3) to 5), the tension between the stands is used by the tension measuring system. However, in actual rolling mills, it is difficult to install a tension meter that can measure tension, and even if it is installed, the looper touches the plate and the tension can be measured after a certain time. The problem is that there is no way to measure tension before it starts.

An object of the present invention is to solve the above problems, by improving the unit tension set value between the rear end stand in the hot finishing rolling to a compensation value by changing the width of the steel plate of the stan, to improve the quality of the rolled plate, in particular the tip width poor The aim is to be able to reduce the

1 is a configuration diagram schematically showing the structure of a conventional hot rolling mill,

2 is a block diagram showing the structure of a control system proposed in the present invention;

3 is a flowchart illustrating a method for improving hot mapping rolling property according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1. Finishing mill 2. Rolled sheet

3. Looper arm 4. Looper roll

5. Pedometer Between Stands

10. SCC setting device 20. Width measuring device

30. Width variation judging device 40. Width over judging device

50. Width shortage judging device 60. Tension compensation gain calculating device

70. Compensation tension set point 80. Looper PLC

According to an aspect of the present invention for achieving the above technical problem, an apparatus for improving hot mapping rolling property includes: a width measuring device that determines the insertion of the rolled plate from the inter-stand width gauge and measures an actual width value of the rolled plate; A width fluctuation determining device which compares the magnitude of the actual width output from the width measuring device with the target width read from the SCC setting device and determines whether the deviation is within the range of the width fluctuation allowance coefficient; A width excess judging device comparing the actual width output from the width measuring device with the size of the target width read out from the SCC setting device and determining whether the deviation is an excess of the width fluctuation allowance coefficient; _Compare the actual width (W _fbk ) output from the width measuring device with the target width (W _ref ) read from the SCC setting device, and determine whether the deviation is a width deficiency outside the range of the width variation allowance coefficient. Determining width shortage determination device; A tension compensation gain calculating device that calculates a compensation gain to compensate the tension value set by the SCC setting device according to a signal output from one of the determination devices; And a compensation tension setting value calculating device for outputting a compensation tension setting value calculated according to the compensation gain input from the tension compensation gain calculating device to a device for controlling the operation of the looper to control the tension between the stands.

On the other hand, according to another feature of the present invention for achieving the above technical problem hot finishing rolling sheet improving method,

A first step of comparing the actual width W _fbk of the rolled plate measured by the stand-to-stand width gauge with the size of the set target width W _ref read from the SCC setting device to calculate the deviation; A second step of comparing the deviation with a variation width tolerance coefficient set in the SCC setting device to determine whether the actual width is a normal width, an excessive width or an insufficient width; A third step of calculating different unit tension compensation gains according to the actual width state; A fourth step of calculating a compensation tension set value using the unit tension compensation gain calculated in the third step; And a fifth step of controlling tension between the stands by controlling the operation of the looper using the calculated compensation tension setting value.

Hereinafter, an apparatus and a method for improving hot mapping rolling property according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3.

2 is a block diagram showing the structure of the control system proposed in the present invention. As shown in FIG. 2, the hot finishing rolling sheet improving device includes a finishing mill 1 composed of a plurality of stands F4, F5, F6, F7,..., A looper arm 3, Hot finishing rolling line comprising a looper roll 4 and a looper positioned between each stand of the finishing mill 1 and an inter-stand width gauge 5 for detecting the width of the rolled plate 2 located between each stand. SCC setting device 10, width measuring device 20, width fluctuation determination device 30, over-width determination device 40, width failure determination device 50, tension compensation gain calculation Device 60, a compensating tension set point computing device 70, and a plurality of looper programmable logic control (PLC) 80s.

The SCC setting device 10 stores setting values such as tension between stands, width between stands, and width variation allowance coefficient, and the width measuring device 20 receives a width detection signal output from the stand width gauge 5. The measured width value of the rolled sheet 2 is measured. As a result, it can be seen that the rolled plate 2 is metal in the finishing mill 1.

The width fluctuation determining device 30 compares the width of the actual measured steel plate 2 input from the width measuring device 20 with the size of the target width stored in the SCC setting device 10 to allow the deviation to be varied. Determine if it is within the range of coefficients. The excess width determining device 40 compares the width of the actual measured steel plate 2 input from the width measuring device 20 with the size of the target width stored in the SCC setting device 10 to allow the deviation to vary. Determine if the width is out of range of the coefficient. The width failure determining device 50 compares the width of the actual measured steel plate 2 input from the width measuring device 20 with the size of the target width stored in the SCC setting device 10 to allow the deviation to vary. Determine if the width is out of the range of the coefficient.

Meanwhile, the tension compensation gain calculating device 60 calculates a compensation gain for each case in order to compensate the tension value set by the SCC 10 according to the output of each of the determination devices 30, 40, and 50. . That is, when the output of the true value is input from the width fluctuation determining device 30, the tension compensation gain calculating device 60 determines that the measured width is within the width fluctuation allowance range, and the unit tension compensation gains α and β are respectively α = 1. , beta = 0. When the output of the true value is input from the oversize determining device 40, the measured width is determined to be too wide beyond the width fluctuation allowable range, and the unit tension compensation gains α and β are respectively defined by α = (W _fbk -W _ref ) · ?? / 10, β = (α-1) / 10 In addition, when the output of the true value is input from the width failure determining device 50, it is determined that the measured width is out of the width fluctuation allowable range and the width is insufficient, and the unit tension compensation gains α and β are respectively α = 1 and β = (W _ref -W _fbk ) / 100.

In the above, ?? is a width variation allowance coefficient, and is set to 0.2% of the target rolling exit target width. W _ref is the set target width and W _fbk is the width of the steel sheet actually measured.

The compensation gain calculation operation of the tension compensation gain calculating device 60 is expressed as a conditional expression as follows.

(Conditional expression)

One). α = 1, β = 0,

2). (In the case of excess width),

3). (If it is short),

The compensation tension setting value calculating device 70 uses the unit compensation tensions α and β outputted from the tension compensation gain calculating device 60, the tension setting values set in the SCC setting device 10, and the width fluctuation value. The compensated tension setpoint is calculated as in Equation 1.

In the above, tf _ref is a compensated set tension, tf _set is a set tension stored in the SCC setting device 10, and _ΔW is W _fbk -W _ref .

The looper PLC 80 receives the compensated tension setpoint tf _ref outputted by the compensation tension setpoint calculating device 70 and adjusts the tension between the stands by adjusting the angle of the looper.

Hereinafter, referring to FIG. 3, an operation of an apparatus for improving hot mapping rolling property according to an embodiment of the present invention will be described.

3 is a flowchart illustrating a method for improving hot mapping rolling property according to an embodiment of the present invention. As shown in FIG. 3, when the finishing rolling line operation is performed, the actual width W _fbk of the steel sheets 2 located between the stands is measured to determine whether the steel sheets are inserted (S100).

Here, the process (S100) is the width information of the steel sheet is detected by the stand width gauge (5), the width measuring device 20 is performed by measuring the actual width (W _fbk ) of the steel sheet (2). When the width measuring device 20 measures the actual width of the steel plate 2, the width W _fbk is output to the width fluctuation determining device 30, the excess width determining device 40, and the width failure determining device 50. do.

Then, the width fluctuation determination device 30, the excess width determination device 40 and the width failure determination device 50 is the target width (W _ref ) between the stand set in accordance with each rolling conditions read from the SCC setting device 10, The width fluctuation allowance coefficient ?? is read (S110), and the width W _fbk is input from the width measuring device 20, and the two widths W _fbk and W _ref are compared (S120).

When the devices 30, 40, and 50 obtain a difference between two widths (W _rbk -W _ref ) through the comparison (S120), the devices 30, 40, and 50 determine whether the obtained difference is a value within a range of a width variation allowance coefficient (??). Determine (S130).

In the determination (S130), if the difference between the two width is within the range of the width variation allowance coefficient (??), the width fluctuation determination device 30 generates an output of the true value and outputs to the tension compensation gain calculating device 60 If the difference between the two widths is out of the width variation allowance coefficient range, one of the overweight determination device 40 and the shortage determination device 50 generates a true value and outputs it to the tension compensation gain calculating device 60.

When the difference between the two widths is within the allowable width variation coefficient (??), the condition corresponds to condition 1). Accordingly, the tension compensation gain calculating device 60 sets the unit tension compensation gains (α, β) to 1. , And 0 are output to the compensation tension set value calculating device 70 (S140).

On the other hand, when the difference between the two widths is outside the allowable coefficient of variation (??), the widths are excessive or insufficient as in Equation 2) and Equation 3). In this case, when the width is excessive, the output value of the true value is generated by the oversize determination device 40, and the tension compensation gain calculating device 60 When the phosphorus unit tension compensation gain value is output (S150, S160), and the width is insufficient, the output of the true value is generated in the width shortage determination device 50, and the tension compensation gain calculating device 60 The unit tension compensation gain value is output (S150 and S170).

Here, the true value is output to only one of the determination devices 30, 40, and 50 and is input to the tension compensation gain calculating device 60.

The unit tension compensation gains (α, β) output from the tension compensation gain calculating device 60 are input to the compensation tension setting value calculating device 70 to calculate the compensated tension setting value tf _ref through Equation 1 (S180). ).

Then, the compensated tension set value (tf _ref ) is input to each of the looper PLC (80) 5, 6 PLC 80 to adjust the angle of the looper, thereby adjusting the tension between the stand (S190) .

Therefore, in the present invention, when the width is excessive, a slight tension is added to the set tension, and when the width is insufficient, a slight tension is reduced by the set tension.

For example, in the case of excessive width, when the width variation tolerance (??) is 2 [mm] and ΔW is 6 [mm], α = 6/10 * 2 = 1.2, β = 0.2 / 10 = 0.02, and the compensated tension set value tf _{ref according} to the equation 1 becomes tf _ref = tf _set * 1.2 + 0.2 * 6. Therefore, if the tension setpoint (tf _set ) is 1 [Kg / mm ² ], the compensated tension setpoint (tf _ref ) becomes 1.32 [Kg / mm ² ] and the tension setpoint is increased by about 32% to solve the problem of over-width. do.

On the other hand, in the case of the lack of width, when the width fluctuation coefficient (??) is 2 [mm] and ΔW is -6 [mm], α = 1, β = 6/100 = 0.06, so that Equation 1 The compensated tension set by tf _ref = tf _ref * 1 +0.06 * (-6), and if the tension set is 1 [Kg / mm2], the compensated tension setpoint is 0.64 [Kg / mm2], about 36%. The tension setpoint is reduced to solve the problem of poor quality due to poor width.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

The present invention compares the width of the steel sheet with the set value in hot finishing rolling, and improves the degree of unit tension set value between the rear stands with the compensated tension according to the comparison result, thereby reducing the quality degree of the rolled plate, in particular, the tip width defect.

Claims (8)

SCC (Supervisory Control Computer) setting device that applies a number of setting values including looper installed between the stand of the finishing mill, the stand-to-stand width gauge that measures the width of the rolled plate, and the stand-to-stand tension, the width between the stand, and the allowable width variation. In the hot finishing rolling line comprising an apparatus for improving the gutter A width measuring device for determining the insertion of the rolled plate from the inter-stand width meter and measuring the actual width value of the rolled plate; A width fluctuation determining device which compares the magnitude of the actual width output from the width measuring device with the target width read from the SCC setting device and determines whether the deviation is within the range of the width fluctuation allowance coefficient; A width excess judging device comparing the actual width output from the width measuring device with the size of the target width read out from the SCC setting device and determining whether the deviation is an excess of the width fluctuation allowance coefficient; _Compare the actual width (W _fbk ) output from the width measuring device with the target width (W _ref ) read from the SCC setting device, and determine whether the deviation is a width deficiency outside the range of the width variation allowance coefficient. Determining width shortage determination device; A tension compensation gain calculating device that calculates a compensation gain to compensate the tension value set by the SCC setting device according to a signal output from one of the determination devices; And A hot finishing rolling plate including a compensation tension setting value calculating device for outputting a compensation tension setting value calculated according to the compensation gain input from the tension compensation gain calculating device to a device for controlling the operation of the looper to control the tension between the stands. Sex enhancement device. The method of claim 1, The variation width tolerance coefficient is, An apparatus for improving hot finishing rolling property, characterized in that set to ± 0.2% of the set rolling plate target width. The method of claim 1, The tension compensation gain calculating device, Unit tension compensation gains α and β are set to α = 1 and β = 0 according to the output of the width fluctuation determination device, According to the output of the over-judgement device Set to, According to the output of the shortage determination device Hot filament rolling performance improving device, characterized in that set to. The method of claim 3, The apparatus for compensating tension setpoint is configured to calculate a compensating tension setpoint (tf _ref ) through the following equation. tf _ref; Compensated set tension, tf _set: set tension stored in the SCC setting device, _ΔW : W _fbk -W _ref. SCC (Supervisory Control Computer) setting device that applies a number of setting values including looper installed between the stand of the finishing mill, the stand-to-stand width gauge that measures the width of the rolled plate, and the stand-to-stand tension, the width between the stand, and the allowable width variation. In the hot finishing rolling line comprising a method for improving the flow through A first step of comparing the actual width (W _fbk ) of the rolled plate measured from the inter-stand width gauge with the size of the set target width (W _ref ) read from the SCC setting device to calculate the deviation; A second step of comparing the deviation with a variation width tolerance coefficient set in the SCC setting device to determine whether the actual width is a normal width, an excessive width or an insufficient width; A third step of calculating different unit tension compensation gains according to the actual width state; A fourth step of calculating a compensation tension set value using the unit tension compensation gain calculated in the third step; And And a fifth step of controlling tension between the stands by controlling the operation of the looper using the calculated compensation tension setting value. The method of claim 5, The hot finishing rolling plateability improvement method characterized by setting to ± 0.2% of the set target width of the rolled plate. The method of claim 6, The third step, If the actual width W _fbk of the rolled sheet is the normal width, the unit tension compensation gains α and β are set to α = 1 and β = 0, respectively. If the actual width W _fbk of the rolled sheet is too wide, Set to, If the actual width W _fbk of the rolled sheet is short in width, Hot finishing rolling sheet improving method characterized in that it is set to. The method of claim 7, wherein In the fourth step, a method for improving hot mapping rolling property, characterized in that for calculating a compensation tension set value (tf _ref ) through the following equation. tf _ref; Compensated set tension, tf _set: set tension stored in the SCC setting device, _ΔW : W _fbk -W _ref.