JPS587584B2 - Control method of wrapper roll in winder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling wrapper rolls in a winder of a hot rolling facility.

When winding hot-rolled steel strips by a down coiler, determining when to pull the wrapper roll off the down coiler mandrel is extremely important in order to obtain a desired normal coil.

In other words, if the wrapper roll is pulled from the mandrel of the down coiler too early, the strip will be wound without the strip at the center of the coil being tightly wrapped around the mandrel, resulting in a so-called bowl-shaped coil. If the wrapper roll is withdrawn too late, the succeeding strip that is wound over the tip of the strip will be strongly pressed against the tip of the strip, resulting in a so-called end mark. This is because, as a result, a steel strip coil having defective parts is formed, which reduces the product yield and causes problems in the subsequent handling of the coil.

Conventionally, the timing for pulling off the wrapper roll during winding of hot rolled strip steel using a down coiler has been mainly determined by detecting a sudden increase in the load current of the down coiler's mandrel drive motor. This is because the timing when the predetermined tension is generated in the steel strip (that is, the time when the slack in the steel strip that has already been wound around the mandrel has disappeared) and the timing when the load current of the mandrel driving motor increases do not completely coincide. If the increase in the load current of the mandrel driving electric motor is considered as the completion of winding the tip of the strip steel and the wrapper roll is removed from the mandrel, the wrapper roll will be removed from the mandrel prematurely, and as a result, the center of the coil will be The coils could not be tightly wound, often resulting in bowl-shaped or telescope-shaped coils.

Generally, the increase in the load current of the mandrel drive motor is greatest at the moment when the tip of the strip is pressed against the mandrel by the wrapper roll, but the increase in the load current of the mandrel drive motor at this time is a so-called overshoot. After this, when a predetermined tension is generated in the strip steel on the down coiler entry side, the load current of the mandrel drive motor decreases from the overshoot value, so the strip being wound is adjusted to the overshoot value of the load current of the mandrel drive motor. Assuming that a predetermined tension has been established in the steel will lead to a major error in determining the optimum timing for unpulling the wrapper roll.

Therefore, in the past, the timing for pulling the latspar roll in a down coiler was determined based on the intuition of a skilled worker while referring to changes in the load current of the motor for driving the mandrel. varies depending on the steel type of the rolled steel strip, rolling conditions, and winding conditions, and if the operator changes, the timing at which the wrapper rolls are not pulled will also change; However, it has not been possible to prevent the occurrence of defective coils or the occurrence of defective parts such as end marks on the steel strip.

The inventor of the present invention has made various attempts to determine the optimal timing for unpulling the wrapper roll in a down coiler based on the experience in the strip steel winding operation in a hot rolling facility. It has been discovered that the Ratspur roll can be automatically pulled off the mandrel.

According to the inventor's attempt, the slip ratio of the steel strip on the winder mandrel reaches a predetermined value when the number of windings of the tip of the steel strip on the winder mandrel reaches the number of windings n obtained by the following formula. It was found that by using the fact that the load current of the mandrel drive motor matches a predetermined value as an indicator for retracting the wrapper roll, it is possible to automate the wrapper roll operation and prevent the occurrence of defective coils and winding failures. .

In addition, in the above formula, n and 0 are the predetermined empirical standard number of turns, t is the steel strip thickness,
Wo is the predetermined steel strip width, W is the measured strip width at the exit side of the rolling mill, T is the strip temperature at the time of winding, To is the predetermined steel strip temperature at the time of winding, and δy is the tensile strength of the steel strip material. , δ0 is a predetermined tensile strength of the steel strip, and a1 to a3 are empirical coefficients.

In addition, the slip ratio is the ratio between the length of the strip that has passed through the pinch rolls on the input side of the winder and the length of the strip that has been wound up on the mandrel of the winder, and these are the ratios of the number of rotations of the pinch rolls and the number of rotations of the mandrel. It can be found from

The basis of the formula for calculating the required number of windings n of the tip of the steel strip is as follows.

The standard number of turns nO is the number of turns that does not cause slippage and is determined theoretically, and is set to about 7 for a minimum plate thickness of 1.2 mm, for example.

However, since the value of n0 varies depending on the structure of the coiler, it is set for each coiler.

is a correction term for the number of windings depending on the plate thickness.

The thicker the plate, the smaller the gap between the mandrel and the guide around the mandrel (fixed to the wrapper roll).
It became clear that the winding ability around the mandrel was improved.
Furthermore, it was experimentally confirmed that there is a correlation between the number of windings and the plate thickness.

a2(w-w0) is a correction term for the number of windings depending on the board width.

As the plate width increases, the shape of the steel strip tends to deteriorate, and the adhesion between the coils also deteriorates, so it is necessary to make a correction according to the increase or decrease in the plate width with respect to the reference plate width W0.

Furthermore, the hot yield stress changes depending on the steel type and the winding temperature, and generally the higher the tensile strength δy, the worse the winding shape, so the required number of windings n needs to be corrected accordingly.

The correction term is.

Therefore, the number of turns n at which the steel strip does not substantially slip can be determined by the above formula.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the attached drawing, 1 is the down coiler mandrel, 2,
3 is a ratchet roll arranged on the circumferential surface of the mandrel 1.

Each wrapper roll 2, 3 has a slide 2A, 3A that can move forward and backward in the radial direction with respect to the axis of the mandrel 1, and at the tip of each slide, a pair of pressure rolls 2B,
3B is rotatably supported.

Each slide 2A, 3A has a pneumatic cylinder 2C for moving each slide forward and backward in the radial direction with respect to the axis of the mandrel 1.
, 3C are connected, and each pneumatic cylinder 2C, 3
Control valves 2E and 3 are connected to pneumatic pipes 2D and 3D connected to C.
E is provided, and these control valves 2E and 3E are connected to a control device 6.
electrically connected to.

A pinch roll 7 is provided between the input side of the down coiler and the output side of the rolling mill (not shown), and a temperature detector 8 is installed along the pass line of the strip S on the output side of the final stand of the rolling mill. ,
A plate thickness detector 9, a steel band tip detector 10, and the like are arranged.

The pinch roll 7 is driven by an electric motor (not shown), and a pulse generator 11 for speed and rotational speed detection is connected to the drive shaft of the pinch roll 7.

A driving electric motor 12 is connected to the mandrel 1 of the down coiler, and a pulse generator 13 for speed and rotational speed detection is connected to the electric motor 12 or the shaft of the mandrel 1.

On the other hand, an ammeter 14 for detecting load current is connected to the armature circuit of the mandrel driving motor 12, and the ammeter 14 is also electrically connected to a comparator 15.

A gate circuit 16 is connected to the pulse generator 11, and a strip tip detector 10 is electrically connected to the gate circuit 16.

A time calculator 17 is also electrically connected to the pulse generator 11, and a strip steel tip detector 10 is connected to the time calculator 17.
are electrically connected.

This time calculator 17 calculates the time from when the tip of the steel strip passes through the pinch rolls 7 to when the tip of the strip reaches the outer periphery of the mandrel 1 and is pressed against the outer periphery of the mandrel 1 by the first wrapper roll 2. It is a calculation.

A gate circuit 18 is electrically connected to the time calculator 17, and this gate circuit 18 is connected to the output value of the pulse generator 13.

Reference numeral 19 denotes a required number of windings calculation unit, and this calculation unit 19 is used to calculate the required number of windings expressed by the above formula. A board width detection signal W from a board width detector (not shown) and other setting values are inputted.

On the other hand, an arithmetic unit 20 is connected to the output side of the gate circuit 16, and a pulse signal generated by the pulse generator 11 is input to this arithmetic unit 20.

This calculator 20 calculates the length L of the steel strip that has passed through the pinch rolls 7.
1, and a slip ratio calculator 21 is connected to its output side.

A required winding length calculator 22 is connected to the output side of the calculator 19.

This calculator 22 calculates the required winding length based on the required number of windings n calculated by the calculator 19 and the output signal of the plate thickness detector 9 using the calculation formula LO=π(nDr+n2t). The output of this calculator 22 gives the length LO of the strip to be wound onto the winder mandrel 1.

(Dr: mandrel diameter, t: steel strip thickness) Gate circuit 1
A computing unit 23 connected to the output side of 8 calculates the apparent length L2 of the steel strip wound around the mandrel 1 based on the rotational speed of the winding mandrel 1 using the equation L2-π(Dr+2tnR)N.
This is a calculation based on R.

In this equation, nR is the measured number of actual turns on the mandrel and NR is the rotational speed of the mandrel, which are obtained by pulse generator 13.

Further, t is the strip steel plate thickness, which is obtained from the plate thickness detector 9.

A comparator 24 for comparing the output of the calculator 22 and the output of the calculator 23 is connected to the calculators 22 and 23, and this comparator 24 generates a drive signal for the slip ratio calculator 21.

The output side of the computing unit 20 and the output side of the computing unit 23 are connected to a slip ratio computing unit 21 so that a slip ratio Q expressed by the ratio L2/L1 of the output signal values of both computing units 20 and 23 is computed. It has become.

This slip ratio calculator 21 turns on when there is an input signal from the comparator 24, and inputs an output signal representing the slip ratio to the next stage comparator 25.

The comparator 25 is for comparing the reference slip ratio and the output signal of the calculator 21, and generates an output when the output value of the calculator 21 is lower than the reference slip ratio.

The gate circuit 26 connected to the output side of the comparator 25 is configured to receive the output signal of the comparator 25 and the output signal of the comparator 15, and is driven when these two output signals are applied. generates an output signal for driving the control device 6.

The control device 6 is a control valve 2E of each tenono soo low nore 2 and 3.
, 3E, and switches the control valves 2E, 3E when there is an input signal from the gate circuit 26.

Next, a control sequence in the above configuration will be explained.

At the point when the tip of the steel strip S leaves the hot rolling mill (not shown) and passes through the pinch rolls 7, the information is detected by a plate thickness detector 9, a temperature detector 8, a plate width detector (not shown), etc. The output signals of are input to the arithmetic unit 19, and the arithmetic unit 19 receives these input signals and other setting input information no, δy, δo, Wo,...
. . . The required number of windings n on the mandrel 1 is calculated according to the formula.

The arithmetic unit 22 connected to the output side of the arithmetic unit 19 is the arithmetic unit 1
Based on the output signal of 9 and the output signal of plate thickness detector 9, the required winding length LO on the mandrel 1 is calculated according to the formula LO-π(nDr+n2t).

On the other hand, when the tip of the steel strip S passes through the pinch roll 7, an output signal from the strip tip detector 10 is generated, and this output signal is input to the gate circuit 16 and the time calculator 17. 16 is opened to input the output pulse of the pulse generator 11, that is, the rotation speed signal Np of the pinch roll to the calculator 20, while the time calculator 17 is driven to input the output pulse of the pulse generator 11, that is, the rotation speed signal Np of the pinch roll to the calculator 20. The time required for the tip of the steel strip S to reach the circumferential surface of the mandrel 1 is calculated based on the speed signal Np.

The time calculator 17 does not generate an output signal during the calculation time.

On the other hand, the calculator 20 calculates the length L1 of the strip passing through the pinch roll 7 according to the formula L1=πDpNp (Dp: pinch roll diameter) based on the output pulse of the pulse generator 11, that is, the rotational speed signal Np of the pinch roll 7. Then, the calculated value is applied to the slip ratio calculator 21.

When the tip of the steel strip S reaches the circumferential surface of the mandrel 1, an output signal is generated from the time calculator 17, and this signal is applied to the gate circuit 18, which causes the gate circuit 18 to
The output pulses of the pulse generator 13, which is connected directly to the mandrel 1, are applied to the arithmetic unit 23 through the gate circuit 18.

(Since the mandrel 1 is already rotating at the lead speed before the tip of the steel strip reaches, the pulse generator 1
3, that is, the rotational speed signal NR and rotational speed signal nR of the mandrel 1 are preferably input to the calculator 23.

) As a result, the calculator 23 calculates the apparent length L2 of the steel strip being wound around the mandrel 1 based on the formula L2=πNR(Dr+2tnH) (Dr: mandrel diameter), and compares the calculated values. 24 and slip ratio calculator 21.

On the other hand, the load current of the mandrel drive electric machine 12 is measured by the ammeter 14.
The output signal A of the ammeter 14 is applied to the comparator 15.

The comparator 15 generates an output signal to the gate circuit 26 only when the ammeter output signal A is within the set range A0.

This is illustrated in Figure 2A.

That is, FIG. 2 A, B, and C show load current A1 slip ratio Q and ON/OFF of gate circuit 26 versus time on the horizontal axis.
As shown in Fig. 2A, the load current A rises at the same time (at the winding start point The setting value Ao or higher.

The upper limit of the setting range A0 is smaller than the overshoot value of the load current, and the lower limit is set to a predetermined value larger than the no-load current value.

When the required winding length Lo and the apparent winding length L2 match, a drive signal is applied from the comparator 24 to the slip ratio calculator 21, and the slip ratio calculator 21 receives input from the calculators 20 and 23. The slip ratio Q based on the input signal
=L2/L1 is calculated, and the calculation result is applied to the comparator 25.

The comparator 25 compares the input signal Q with a preset slip ratio Qo, and applies the input signal to the gate circuit 26 when the magnitude of the signal Q is smaller than the set value Qo.

This is illustrated in Figure 2B.

That is, the slip ratio Q begins to decrease at the same time (point X) when the steel strip S starts being wound around the mandrel, and eventually becomes smaller than the set value Qo as the number of windings increases.

The gate circuit 26 is opened only when there are simultaneous inputs from the comparison paths 15 and 26, and generates an output to the control device 6.

This is illustrated in Figure 2C.

In other words, at time Y when winding is considered complete, the gate circuit 2
6 is turned ON and the control device 6 is activated.

Therefore, the control device 6 controls the support slides 2A of the pressure rolls 2B and 3B that had been pressed against the circumferential surface of the mandrel 1 until then.
, 3A from the circumferential surface of the mandrel 1.

On the other hand, as shown in Fig. 3 A, B, and C, even if the load current A is higher than the set value A0, the slip ratio Q
is not lower than the set value Qo, the gate circuit 26 is turned on.
does not occur, and the control device 6 does not operate.

That is, the wrapper rolls 2 and 3 do not retreat.

As described above, according to the present invention, it is possible to eliminate the conventional wrapper roll operation method that relies on the intuition of workers, thereby reducing the number of personnel required for winding steel strips, preventing the occurrence of defective coils, and preventing winding failures. This can contribute to the avoidance of

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating the configuration of an apparatus for implementing the method of the present invention; FIGS. 2A, B, and C are graphs illustrating the operation of the apparatus in FIG. 1; FIGS. 3A, B, and C 2 is a graph showing another example of the operation of the device shown in FIG. 1. FIG. 1... Mandrel, 2, 3... Ratspar roll, 6...
Control device, 7... Pinch roll, 8... Temperature detector, 9
...Plate thickness detector, 10...Strip tip detector, 11, 13
... Pulse generator, 12 ... Mandrel drive electric motor,
14... Ammeter, 17, 19, 20, 21, 22, 24
...Arithmetic unit.

Claims (1)

[Scope of Claims] 1. The number of turns of the steel strip wound on the winding mandrel reaches the corrected number of turns determined by the following formula based on the standard number of turns, plate thickness, plate width, tensile strength, and coiling temperature, and A method for controlling a wrapper roll in a winder, characterized in that the wrapper roll is released when the slip ratio of the strip steel to the take-up mandrel and the load current of the drive motor of the take-up mandrel exceed predetermined values. Here, n: Corrected number of turns (required number of turns) no: Reference number of turns t; Steel strip thickness W; Actual plate width Wo; Reference plate width T; Steel strip temperature T0; Reference temperature δy; Tensile strength of the steel strip material δ0 ; Reference tensile strength a1 to a3; Coefficient. 2. A wrapper roll control method in a winder equipped with a wrapper roll that is pressed against the circumferential surface of a winding mandrel, wherein the pinch roll is controlled from the time when the tip of the steel strip passes through the pinch roll on the entry side of the winder. A first calculated value is obtained by calculating the length of the steel strip that has passed through based on the detected value of the rotational speed of the pinch roll, and at the time when the tip of the steel strip reaches the circumferential surface of the winder mandrel. A second calculated value is obtained by calculating the apparent length of the steel strip wound around the mandrel based on the detected value of the rotational speed of the mandrel, and the temperature of the steel strip when passing through the pinch rolls is A third calculated value is obtained by calculating the length of the steel strip to be wound on the mandrel from the corrected number of turns and the plate thickness, which are determined by the following formula based on information such as plate thickness, plate width, and tensile strength. At the same time, when the second calculated value and the third calculated value match, a slip ratio represented by the ratio of the first calculated value and the second calculated value is determined so that the value of the slip ratio is determined. and when the detected value of the load current of the mandrel drive motor after the tip of the steel strip is wound around the mandrel is larger than a predetermined value, the wrapper roll is pulled off from the circumferential surface of the mandrel. A method for controlling the wrapper roll in a winder. Here, n: Corrected number of turns (required number of turns) no; Standard number of turns t; Steel strip thickness W; Actual width Wo; Reference strip width T; Steel strip temperature TO + reference temperature δy; Tensile strength of the steel strip material δo; Standard Tensile strength a1 to a3; coefficient.