JPH04220109A - Control device for multi-stand continuous rolling line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The invention provides a storage device for values specific to a rolling program, such as rotational speed target value, armature current, exit cross-section, and derives values, such as the tension of the rolled material between stands. The present invention relates to a control device for a multi-stand continuous rolling line, in particular a bar steel line, with a computer part for calculating stresses.

0002

[Prior Art] Federal Republic of Germany Patent Application Publication No. 280
From Publication No. 0197, a method and a device for controlling the tensile stress of a rolled product between roll stands of a tandem rolling line are known as related prior art, and in this case, the tensile stress in the rolled product is detected. It is calculated based on the detected roll reaction force and the detected roll torque, and is controlled to a constant value via a tensile stress control compensation signal that compensates for deviations in the tensile stress. A reference lever arm for the i-th roll stand is calculated and stored in a memory for controlling the longitudinal stress of the rolled product between the i-th roll stand and the (i+1)th roll stand. used for. At this time, among the physical quantities of the rolling process, including the standard lever arm, the thickness of the rolled product at the entrance and exit of the i-th roll stand, the roll gap of the i-th roll stand, and the roll reaction force at the i-th roll stand, Two or more of these are used. The tensile stress is then calculated on the basis of the calculated lever arm and the detected values of the roll reaction force and roll torque.

Controls of this type are too expensive for certain applications, especially when rolling profiles or bars. This applies to the modernization of existing relatively slow operating rolling mills.

0004

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control for the tensile stress of a rolled product which is significantly cheaper than known minimum tension control devices and is particularly suitable for bar and section rolling lines and serves as a minimum tension control. The goal is to provide equipment. In particular, it is advantageously avoided that the rolling line has to be equipped with expensive force-measuring sensors, for example for roll reaction forces or roll reaction lever arms, in addition to the normally used photovoltaic cells and current-voltage measuring instruments. be.

[0005]

The object is based on the invention, in which the rotational speed of the individual stands of the rolling line is controlled via a rotational speed auxiliary setpoint value for minimum tension control;
At that time, the rotational speed auxiliary target value is based on the predetermined calculation rule,
This is solved by being formed while taking into account the memorized experience values.

[0006]

[Operation and Effect] The device based on the present invention requires only a relatively simple computer equipped with a storage device, and the storage device stores and uses important electrical values that occur during operation of the rolling line. The evaluation results in a minimum tension control method.

According to an embodiment of the invention, the empirical values are calculated and stored by an auxiliary program and used for controlling the rolling process with constant modification. Due to the continuous modification or learning method, the control device according to the invention behaves like a control method using a closed control circuit, whereby a simple automatic optimum tension adjustment of the rolling line is achieved. Only the response time of the control is greater than in the case of direct control by sensors, but this is often not a problem, especially in the case of bar and section lines. This is because here small deviations from the optimum minimum tension are less of a hindrance than in the plate rolling line.

According to another embodiment of the invention, the rotational speed auxiliary setpoint value follows the calculation rule: nZ*%=KE
- Calculated by (JA1-JA2-ΔJA*), in which case KE is calculated from the stored experience value. The empirical value KE is then entered in the form of a change in rotational speed in percent per N/mm2, and ΔJA* is likewise entered in N/m2.
It is input in the form of tensile stress in m2 and converted into a current value by the computer. Tension control, particularly minimum tension control, is performed while taking into account the tensile stress generated in the rod. By varying the rotational speed by percentages, the values of which vary in the range of fractions of a percent, a precise control is achieved which takes into account the requirements of bar and section lines in particular, but which can also be used in the case of plate rolling lines. It has been found that even relatively long control cycles do not lead to tolerance violations under normal conditions.

In order to carry out the invention, the armature current J
A is especially filtered by a Butterworth filter or similar filter. A very advantageous smoothing of the armature current takes place thereby, and representative current average values are easily obtained for subsequent calculations.

According to the above-mentioned simple calculation rule for forming the rotational speed additional target value nZ*% through the empirical value KE in this invention, JA1 is calculated before the succeeding stand bites, that is, when there is no influence from the succeeding stand. represents the armature current, JA2 represents the armature current after biting into the trailing stand, i.e. under the influence of the trailing stand, and ΔJ
A* represents the tension current target value, which is separately generally calculated in advance. This calculation is performed based on stored rolling data and certain rolling line parameters such as reduction ratio and magnetic field weakening rate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to drawings showing an embodiment of a control device based on the present invention.

In FIG. 1, the individual roll stands of a rolling line with a relatively high rolling stock speed are designated by the reference numeral 1 and an index. These stands are passed one after another in the direction of the arrow by the schematically indicated rolling stock. The minimum tension control by the control device 2 is shown in this example between roll stands 1 m 2 and 1 m+1. Armature currents JA1 and JA2 are measured on a 1m roll stand.
It is sent to the signaling device 2 via the signal path 12. Signal device 2
Then, the rotational speed auxiliary target value nZ*% is calculated and sent via the signal path 13 to the stand 1m+1. stand 1
The transit time of the rolled material between m and 1m+1 is divided into a damping time tA1 for stabilizing the jamming impact at stand 1m and a safety time tS1, with the damping time tA1 being followed by the next stand 1m+1. The target value change for is calculated. The control direction is indicated by the solid line 13, but according to the dashed line 14' it can therefore also extend in the opposite direction. Adjustment of the individual stands is such that when the rolling material speed is high, for example when the rolling material head travel time from stand to stand is less than 1 to 2 seconds, the respective rotational speed auxiliary target value is set at the time of the next passing of the rolling material. Changes will be made for the first time. The control cycle therefore spans from bar to bar.

In FIG. 2, a roll stand of a rolling line with a relatively low rolling stock speed is designated by 1n, the construction and mode of operation of the control device 2 are in principle the same as in FIG.
However, here the control of the next stand 1n+1 takes place already during the passage of the same rolling stock. This is made possible by the relatively low rolling stock speed, in which the jamming impact of the stand 1n is first stabilized during the decay time tA1, the current value is stored in the control device 2n-1, and the adjustment is carried out. The resulting new load current is stabilized during the decay time tB1 and the current JA1 is stored for calculation of the minimum tension controller 2n. Here too, a safety time tS1 is provided to prevent temporal overlap.

In FIG. 3, reference numeral 2 likewise designates a control device according to the invention, the computer part 2' of which includes a rolling stock path simulation circuit as a model. Furthermore, the control device 2 has a target value setting section 2'',
A rotational speed setpoint value n* is formed in this setting, this signal being designated by the reference numeral 11. Reference numeral 2'' indicates a parameter input unit of the control device 2, to which signals are sent from a keyboard or monitor via a signal path 8. A signal path 9 is sent to the rolling material path simulation circuit via various photovoltaic cells, etc. The respective positions of the rolled product are inputted via the controller 2. Therefore, the control device 2 controls the armature current inputted via the preferably six-pole Butterworth filter 10 into a tension-free state and a tension-applied state. It is possible to input the data separately into the storage devices 3 and 4 in association with the position.

Armature current signals for the untensioned and tensioned states reach the difference forming device 5 from the storage devices 3 and 4, and the difference forming device 5 stores the tension current target value ΔJA*, the rotation speed, and the rolling speed. The empirical values related to the program are sent from the parameter input unit 2''.The difference forming device 5 calculates the tension current error ΔJA from these data, and sends it to the multiplier 6 together with the empirical value KE. A rotational speed setpoint value n* is formed in relation to the rolling stock speed in the nip of the rolling stock according to FIG. 1 or during the rolling of a bar according to FIG. Reference numeral 7 designates a relay unit which processes the setpoint value n* via the setting unit 2''. Units 3 to 7 together form the calculation part of the control device, which constantly calculates the rotational speed target value n* and outputs it in a timely manner.

At this time, the conversion from tensile stress to armature current is as follows: ΔJA*=AZ* ・AA ・dW ・n* ・JAN
/(2・i・PN・9555), where ΔJA* is the tensile current target value (A), AZ* is the tensile stress in the rolled material (N/mm2), and AA is the exit cross-sectional area (
mm2), dW is the roll diameter (mm), n* is the current rotational speed target value (rpm), JAN is the motor armature rated current (A), i is the reduction ratio, and PN is the motor rated output (kW). means.

[Brief explanation of the drawing]

1 is a partial schematic representation of a rolling line with a control device according to the invention and a relatively high rolling material speed; FIG.

FIG. 2 is a partial schematic representation of a rolling line with a control device according to the invention and a relatively low rolling material speed;

FIG. 3 is a block diagram of an embodiment of a control device according to the invention.

[Explanation of symbols]

1 Roll stand 2 Control device 2' Computer part 2″ Parameter input unit 2′″　Target value setting section 3, 4 Storage device 5 Difference forming device 6 Multiplier

Claims (9)

[Claims] 1. A control device (2) for a multi-stand continuous rolling line, comprising a storage device for values specific to the rolling program and a computer part for calculating the values derived. For this purpose, the rotational speed of the individual stands (1n) of the rolling line is controlled via a rotational speed auxiliary setpoint value, the rotational speed auxiliary setpoint value being a memorized empirical value (KE) according to a predetermined calculation rule.
A control device for a continuous rolling line with multiple stands, characterized in that it is formed while taking into account the following. 2. The control device according to claim 1, wherein the empirical value is calculated by a disturbance amount evaluation program, stored, and used for controlling the rolling process. [Claim 3] The rotational speed auxiliary target value is calculated according to the following calculation rule: nZ*%=KE ・(JA1-JA2-ΔJA
*) Calculated by KE
3. The control device according to claim 1, wherein: is calculated from stored experience values. 4. The empirical value KE is formed in the form of the rotational speed change in percent per N/mm2 and ΔJA
4. Control device according to claim 1, characterized in that * is formed in the form of a tensile stress in N/mm@2. 5. Control device according to claim 1, characterized in that the armature current JA* is filtered, in particular by a Butterworth filter or a similar filter. 6. Control device according to claim 1, characterized in that the empirical value KE is calculated anew after a control movement exceeding a limit value. 7. Control according to claim 1, characterized in that the tension setpoint value required for the control is calculated on the basis of tension actual value tolerances during a plurality of uncontrolled passes. Device. 8. Storage device (3, 4) for the armature current in the untensioned and tensioned state, a difference-forming device (5) and a difference-forming device (5) for the stored armature current. Claims 1 to 7 further comprising a multiplier (6) for multiplying the output value of ) by an empirical value (KE).
A control device according to one of the above. 9. The method according to claim 1, further comprising a computer section (2') equipped with a rolling material path simulation circuit, a parameter input unit (2'') and a target value setting section (2'''). The control device described in one.