JPH02197310A - Method for controlling continuous rolling mill - Google Patents

Abstract

PURPOSE:To maintain roll dimensional accuracy for a long time by detecting a size of a rolled stock by a dimension gage installed in the outlet side of a roll group and performing tension control based on a deviation from a target value and considering load balance between respective drivers. CONSTITUTION:A rolled stock 1 is rolled by horizontal rolls 1H, 3H, 5H, 7H and vertical rolls 2V, 4V, 6V, 8V; a dimension gage 2 moves around the outside of the stock 1 by 360 deg. and measures the stock 1 and sends information to a PID computing element 3. A dimension in the horizontal direction is decided by conditions of horizontal rolls 1H-7H and a dimension in the vertical direction is decided by conditions of vertical rolls 2V-8V. Loading conditions of roll drivers 4, 5 are measured and the element 3 performs tension control by considering load balance between respective drivers 4, 5 to bring the stock 1 to be a prescribed size. A highly accurate roll dimension is maintained for a long time to reduce maintenance works and to improve operational conditions.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a continuous rolling mill for controlling the dimensions of rolled material at the exit side of a rolling mill group that continuously rolls steel bars, wire rods, and sections to desired dimension values. The present invention relates to a control method.

(Prior Art) Conventionally, a universal rolling mill (a rolling mill having vertical rolls and horizontal rolls) was used for the roughing stand of the roughing mill of a hot strip mill, and several of these mills were arranged in tandem. In this case, the rolled material was not rolled across two universal rolling mills at the same time.

In this case, rolling was carried out with the roll spacing of the vertical rolls of each universal rolling mill set to an optimal constant value to obtain the desired width of the rolled material at the final outlet of the rough rolling mill. Alternatively, a method has been adopted in which only the final two stands are placed close to each other and the rolled material is simultaneously rolled across the two stands. In this case as well, rolling was carried out with the roll gap between the vertical rolls of each universal rolling mill set to an optimum constant value to obtain the desired width of the rolled material at the final outlet of the rough rolling mill.

In other words, during rolling, the gap between the rolling buses is manually readjusted based on the dimension meter or width meter installed on the exit side, and the dimension meter and other measuring devices have only a monitoring function, and are not used for control. It was generally not used. Note that the gap adjustment mechanism also does not include a lowering device.

On the other hand, in continuous rolling mills, tensionless control is performed between the rolling mills during rolling to suppress compression on the rolled material and control to keep the tension on the rolled material to a minimum. Using this control method, we are working to improve product dimensional accuracy that matches the rolling schedule.

[Problem to be solved by the invention]

Since the conventional continuous rolling mill control method is performed as described above, no specific automated measures have been taken to improve the dimensional accuracy of the product. Furthermore, measuring instruments such as dimension meters were only used as monitors. Therefore, although it is necessary to continuously monitor the dimensions of the rolling mill during rolling, it is necessary to manually monitor the dimensions of the rolling mill, or manual work is required, resulting in a reduction in efficiency in the rolling operation.

This invention was made in order to solve the above-mentioned problems, and uses a dimension meter installed on the exit side of a continuous rolling mill or detects the dimensions of the material on the exit side of the rolling mill, and measures the detected value and the dimension. Based on the deviation from the target value, the tension of one or more sets of any vertical roll and adjacent horizontal rolls is actively controlled in the rolling mill, and this tension control improves the dimensional accuracy of the exit side of the rolling mill. The purpose of this study is to obtain a continuous rolling mill control method that improves the control method.

(Means for Solving the Problems) A method for controlling a continuous rolling mill in this invention measures dimensions by providing a dimension meter or a width meter on the exit side of the rolling mill, and transfers the detected value to a PID calculator. This is compared with a target value, and based on the comparison result, the tension on the rolled material is controlled while considering the load balance of the vertical roll and horizontal roll drive devices during rolling.

(Function) The control method for a continuous rolling mill in the present invention uses the conventional no-tension control loop as is. Then, the required dimensions are measured using a dimension meter or a width gauge installed on the exit side of the rolled material, and the measured values are transferred to a PID calculator to perform tension control calculations for target accuracy control, thereby determining the optimum quality of the rolled material. One or more vertical rolls to maintain dimensional accuracy,
Alternatively, a tension control command is output to the horizontal roll to control the tension on the rolled material.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a conceptual diagram showing a group of continuous steel bar rolling facilities to which the present invention is applied. In the figure, 1 indicates the rolled material, that is, the bar steel, and 3 indicates the PID (proportional, integral, differential) installed in each rolling mill (roll stand). Arithmetic unit, 4 is a horizontal roll drive device, 5 is a vertical roll drive device, 6 is an adder, IH, 3H.

5H and 7H are horizontal rolls, 2V, 4V.

6■ and 8■ are vertical rolls.

Moreover, FIG. 2 shows an elongation characteristic diagram of a rolled material, in which the vertical axis shows unit tension and the horizontal axis shows elongation.

Next, the operation of the present invention will be explained below. first,
- In tension-free control such as boat fishing, tension control is performed within a very small range of the elongation of the rolled material, that is, at a unit tension, for example, about 0 to 0.5 g-+n. However, in the present invention, the tension is actively controlled while being aware of the elongation of the rolled material (steel bar 1 in FIG. 1) that is rolled in the direction of the arrow. However, the tension value of the rolled material (bar ml) to be controlled is determined by the finished dimension of the rolled material detected by the dimension meter 2 on the exit side of the final rolling mill.

Here, the dimension meter 2 performs measurement while rotating 3600 times around the moving steel bar 1 as shown in FIG. 3(a). If the finished dimensions of the steel bar 1 at that time are shown in a diagram, for example, Figure 3 (
b). Horizontal dimension measurement HFB as shown
K is determined by controlling the horizontal rolls IH, 3H, 5H and 7H, and the vertical dimension measurement value VFBK is determined by controlling the vertical rolls 2V, 4V, 6V and 8V. Therefore, the control information for the dimension measurement values (V FBK and HFIIK) by the dimension meter 2 to the PID calculator 3 is based on the calculation formula shown in FIG.
, 5H and 7H1 and Tyrol 2V, 4V, 6V and 8V
Both are given for the axial components that match the respective rolling directions. Then, tension is applied to the steel bar 1 based on the elongation characteristics shown in FIG. 2 so that the steel bar 1 passing through it has an averaged dimension value.

Furthermore, in general, the relationship between material elongation and material diameter for each rolled material diameter when no tension is applied is shown by the relationship shown in FIG. 5 based on a constant mass flow. Under normal usage conditions, the diameter of the rolled material shifts in the positive direction due to wear of the rolls, so it becomes necessary to correct it (in the negative direction). Therefore, in the next control step, calculation of the control tension value is required. A limit is set for tension control in order to maintain this control tension value at a level where breakage due to material deformation cannot be avoided.

Next, a method for selecting a rolling mill that performs the tension control of the present invention will be described below. By executing this tension control, the load on the rolling mill changes as follows. That is, (1) If the load on the rolling mill is reduced by executing this tension control, the load may become negative.

(2) The load on the rolling mill further upstream of the rolling mill that is executing this tension control increases.

Therefore, the torque balance equation during rolling is shown as equation (1).

T QMOT= T ROLL+ b T b c
T t ---- (1) However, TQMOT is the torque generated by the motor TR0LL is the rolling torque bT, and the tension cTy of the rear rolling mill is the control stand (not shown) that applies tension to the tension bar 1 of the front rolling mill to cause elongation. In step 3), as the tension cTf of the front rolling mill increases, the motor generated torque T and MOT decrease.

In addition, in the control stand DC rolling mill, the tension b of the rear rolling mill is
As Tb increases, the motor generated torque T,. 1 increases.

In addition, when determining the tension of the control stand, see Figure 6 (a).
, the principles shown in (b) shall be established. That is, (A) dimensional accuracy is maintained by tensionless control between the final rolling mills.

(B) Check the rolling schedule and control the downstream rolling mill so that the load on the downstream rolling mill is lighter than the load on the direct rolling mill.

(C) ``The downstream control stand is selected from downstream rolling mills with a small rolling reduction.

(D) When the load of a rolling mill further downstream of the direct rolling mill becomes overloaded, similar tension control is applied to other rolling mills, and a plurality of rolling mills are used to share the load.

An example in which the tension control shown in FIG. 1 was attempted under such control conditions is shown by the thick line tension control loop in FIG. 6(b). FIG. 4(a) shows the distribution of the load torque applied to the motor during the control shown in FIG. 2(b).

[Effects of the Invention] As described above, according to the present invention, a dimension meter or a width meter is provided on the exit side of a continuous rolling mill, and by comparing the measurement data and target data, it is possible to determine which vertical roll and the adjacent horizontal roll. Since one or more sets are selected and the tension is controlled in consideration of the load balance during rolling, it can be applied to current equipment by simply changing the control method. In addition, it can be realized at a low cost, and high roll dimensional accuracy can be maintained for a long period of time, which reduces maintenance and significantly improves operating conditions.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a continuous steel bar rolling equipment group showing an embodiment of the present invention, Fig. 2 is a diagram of the elongation characteristics of rolled material, Fig. 3 is a diagram of a dimension meter measurement procedure, and Fig. 4 is a dimension meter measurement value. Fig. 5 is a diagram showing the relationship between the elongation of the rolled material and the material diameter, and Fig. 6 is a model diagram of the continuous steel bar rolling equipment group according to the present invention. In the figure, 1 is a steel bar, 2 is a dimension meter, 3 is a PID calculator, 4 is a horizontal roll drive device, 5 is a vertical roll drive device,
IH, 3H, 5H7H are horizontal rolls, 2V, 4V, 6V
, 8v is a vertical roll. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Procedural amendment (spontaneous) 1. Indication of the case 2. Title of the invention ← Patent Application No. 1-13080 Continuous rolling mill control method 3. Person making the amendment Related Patent Applicant Address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Moriya Shiki 4 Agent Address Postal Code 105 1-4-10 Nishi-Shinbashi, Minato-ku, Tokyo No. 6, Contents of amendment (1) On page 2, line 8 of the specification, the words [of hot strip mills] are amended to read "of steel bars, wire rods, and sections." (2) On page 3, line 12 of the specification, the phrase "minimally" should be amended to read "minimally." (3) From line 17 on page 3 of the specification to line 20 on the same page, the phrase ``Due to the fact that the dimensional accuracy of the product was not utilized...'' was replaced with ``the dimensions of the product with the rolling schedule as the target value.'' Accuracy is maintained, but the measured values measured by various instruments during rolling are not linked to control or target value setting online in real time. (4) On page 4, line 3 of the specification, the statement [Issues such as unavoidable reduction in efficiency] has been changed to "room for consideration in maintaining improved dimensional accuracy."
and correct it. (5) In the fourth line of page 6 of the specification, the word "ru." is amended to read "ru." (6) In the 17th line of page 6 of the specification, the phrase ``Measurement is carried out.'' is corrected to ``Measurement is carried out.'' (7) In the first line of page 8 of the specification, replace the phrase "It is." with "
(Figure 2). ” he corrected. (8) In the second line of page 9 of the specification, the phrase "control stand DC rolling mill" is corrected to "control stand rolling mill." (9) On page 9, line 5 of the specification, the phrase "for tension determination" is amended to read "for determination." (10) On page 9, line 11 of the specification, the phrase "of the direct rolling mill" is corrected to "of the control stand." (11) On page 9, line 12 of the specification, the phrase "the downstream rolling mill is controlled" is corrected to "the downstream rolling mill is controlled." (12) On page 9, line 13 of the specification, the phrase "the downstream control stand is" is amended to read "the control stand rolling mill is". (13) On page 9, line 15 of the specification, the statement ``the load of the rolling mill further downstream of the direct rolling mill'' is corrected to ``the load of the control stand rolling mill''. (14) Correct Figure 2 as shown in the attached sheet. 7. A document containing the amended catalog of attached documents, Figure 2.

Claims (1)

[Claims] In a method for controlling a continuous rolling mill for steel bars, wire rods, or sections in which a plurality of stands of vertical rolls and horizontal rolls are arranged in series, a dimension meter installed on the exit side of the group of vertical rolls and horizontal rolls, or a width Detect the dimensions of the rolled material using a meter,
Tension can be controlled in a rolling mill of one or more sets of any vertical roll and horizontal rolls adjacent to the vertical roll based on the deviation between the value detected by the dimension meter or the width meter and the target dimension value. A PID calculator calculates the control conditions and calculates the PID
Tension control is performed by taking into account the load balance of the vertical roll drive device or horizontal roll drive device during rolling to maintain suitable dimensional accuracy on the exit side of the rolled material based on the tension control command from the computer. A control method for a continuous rolling mill, characterized in that a vertical roll or a horizontal roll can be selected as an object.