JPS583765B2 - Feed forward automatic plate thickness control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a feedforward automatic plate thickness control method.

In plate thickness control using the lock-on method, the exit plate thickness h0 at that time is determined as follows from the rolling force F when the tip of the rolled material is bitten by the roll and rolled and the roll gap S0 at no load. , the target plate thickness in that pass is set to the plate thickness h0.

This lock-on method has the following problems.

To explain this point with reference to the characteristic diagram in Figure 1,
In the lock-on in the second pass, the exit plate thickness h01 at the intersection point P0 of the plastic characteristic curve 101 of the rolled material and the elastic characteristic curve 102 of the rolling mill becomes the target plate thickness, and rolling is performed to the tail end.

However, due to the entrance side plate thickness variation ΔH1, the exit side plate thickness variation Δh1
Assuming that the plate thickness at the exit side of the tail end becomes h01+Δh1, the target plate thickness of the lock-on in the next pass (in the case of a reversible rolling mill) is determined by the plasticity curve 103 of the rolled material and the elastic characteristic curve 104 of the rolling mill. It is not h02 due to the intersection of , but h0 is due to the intersection of the plastic curve 105 and the elastic characteristic curve 104.
2+Δh21.

Or, if the entry side plate thickness variation △H2 is added, the plasticity curve 106
h02+Δh21 at the intersection of the elastic characteristic curve 104 and the elastic characteristic curve 104
+Δh22, and the plate thickness accuracy deteriorates.

In addition, the variation △H in the exit side plate thickness from the target plate thickness in the previous pass is determined by the equation (2) described later, but it is important to know when and how to output the adjustment amount of the screw gap based on the variation. It wasn't taken into consideration.

This invention aims to provide a feed-forward automatic plate thickness control method that eliminates the defects in the lock-on method, controls the screw gap at an appropriate time, and enables more accurate plate thickness protrusion. .

FIG. 2 is a block diagram embodying an embodiment of the feedforward automatic plate thickness control method of the present invention.

In the figure, 1 is a rolled material, 2 is a work roll, 3 is a reduction screw that adjusts the gap between the work rolls, 4 is a reduction screw position detector that detects the position of the reduction screw 3,
5 is a screw drive device that drives the rolling screw, 6 is a load cell that detects the rolling load F, 7 is a computing unit that detects the rotation angle at which the rolling mill begins to extend, and 9 is a lock-on memory that detects the lock-on level described later. The target plate thickness of the lock-on corrected by the correction device 12 is stored in relation to the rotation angle of the work roll 2 as the corresponding rolling mill elongation.

Reference numeral 10 indicates the plate thickness variation ΔH (of the rolled plate (the tip in this pass) locked on by the comparator, which is derived from the following equation in relation to the output of the rotation angle detector 8 and stored.

(Normally, the angle θ is not considered as the biting end.

)) ΔF(θ): Deviation between the rolling pressure at the time of lock-on of the work roll 2 and the rolling pressure at the rotation angle θ during rolling M: Mill constant ΔS(θ): Reduction screw position at the rotation angle θ of the work roll 2 Amount of movement from the rolling screw position at the time of lock-on △H(θ): Variation amount from the target plate thickness at the rotation angle θ of the work roll 2 The calculator 11 calculates the formula not only at the biting end but also at the rolling pass According to (2), the rotation angle θ of the work roll 2
The plate thickness variation at is also calculated and stored in the same manner.

Reference numeral 12 denotes a timing control device that controls the timing at which the thickness variation △H (θ) stored in the previous pass is output in a feedforward manner in the current pass, and its operation will be explained below with reference to Fig. 3. That's right.

Point 301 on the rolled material in the previous pass changes to point 302 in the current pass.
, the relationship is θ2=K(θM−θ1) (3).

However, θ1: Rotation angle of the work roll from the biting end of the rolled material to point 301 in the previous pass θM: Total rotation angle of the work roll from the biting end of the rolled material to the end of the rolling material in the previous pass θ2: In the current pass Work roll rotation angle K from the rolled material biting end to point 302: Output timing conversion coefficient h: Target thickness H for the current pass: Target thickness fn-1 for the previous pass: Advancement rate hn for the previous pass: The advance rate of this pass is △ corresponding to the plate thickness variation △H (θ1) stored in the previous pass when the millwork roll rotation angle θ2 obtained in this way is
The value of H(θ2) is sent to the lock-on level correction device 13 and the reduction screw command device 15.

Note that this case shows the case of a reversible rolling mill. In the case of a tandem rolling mill, the rotation angle of the work roll from the biting end of the rolled material to point 301 in the previous pass is θ1, and that of the current pass is θ1. The previous. If the rotation angle of the work roll from the biting end, which is the same as the pass, to point 302 is θ2, the following equation is obtained.

Furthermore, the point 301 may be any arbitrary point.

Reference numeral 13 denotes a lock-on level correction device, which calculates the value of the following equation from ΔH (θ2) obtained by equation (2) and leads it to the comparator 14.

(The rotation angle in this case indicates the lock-on position.

) In other words, the lock-on memory 9 performs the following calculation.

Reference numeral 15 denotes a screw reduction command device, which sends out a screw reduction movement amount ΔS* from ΔH (θ2).

Furthermore, since lock-on correction is performed immediately after biting, the rotation angle θ
It is also possible to perform calculations by setting the biting end to θ=0 without relating it to .

In the above configuration, the operation will be explained with reference to FIGS. 2 and 4. If there is a change in the entrance plate thickness △H' at the tail end of the previous pass (the tip of the current pass), △ This causes variation in the thickness of the exit side of H.

The exit plate thickness variation ΔH(θ) is expressed by the following equation from equation (2).

In addition, in this pass, the entry side plate thickness △H at the tip of the rolled material
If there is a variation in , the outlet side plate thickness variation Δh is expressed by the following equation.

becomes.

Therefore, in the current pass, the rolling force is stored in the correction lead 9 by the lock-on level correction device 13.

Note that, as described above, at the time of lock-on, it is not necessary to consider the rotation angles θ1 and θ2 as the biting ends.

According to the input formula (2k), the plate thickness variation △H (θ2) is stored in relation to the rotation angle θ2 of the work roll 2, and the previously stored plate thickness variation △H (θ1) is stored in the screw lowering device 15.
Then, the timing control device 12 issues a command ΔS for the amount of movement of the screw down to the screw down device 5 at the position of the rotation angle θ2 corresponding to the rotation angle θ1.

F: The rolling load type screw lowering device 5, which uses the plate thickness h, friction coefficient, etc. determined by the schedule calculation as variables, adjusts the amount according to equation 9 at each position of the rotation angle θ2 of the work roll 2 in this pass, Drive the reduction screw 3.

Control in the next pass is performed in the same way.

As described above, according to the method of the present invention, the drawbacks of the lock-on method can be overcome and more accurate plate thickness control can be realized.

[Brief explanation of drawings]

Fig. 1 and Fig. 4 are characteristic diagrams showing the relationship between plate thickness and rolling force, Fig. 2 is a block diagram embodying an embodiment of the feedforward automatic plate thickness control method of the present invention, and Fig. 3 is a characteristic diagram showing the relationship between plate thickness and rolling force. It is a figure showing the relative relationship of the position of the rolled material in each pass. In the figure, 1 is a rolled material, 2 is a work roll, 3 is a reduction screw 6 is a load cell, 8 is a rotation angle detector, 9 is a lock-on memory, 10 is a comparator, 11 is a calculator, 12 is a timing control device, 13 is a lock-on level correction device, 15
is a screw reduction command device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Correction is made according to the following formula using the amount of variation △H of the lock-on from the target plate thickness in the previous rolling pass at the lock-on position θ2 of the current pass, the deformation resistance Q of the rolled material, and the mill constant M. The target plate thickness in the pass is the plastic characteristic curve of the rolled material regarding the target plate thickness of the Rotsu-on in the previous pass, and the elastic characteristic curve of the rolling mill with respect to the screw position in the current pass. The amount of adjustment of the screw gap of the reduction screw is calculated using the amount of variation from the target plate thickness in the previous pass memorized at each position of the material, the mill constant, and the differential coefficient of the rolling load formula at the target thickness of the current pass. A feedforward automatic plate thickness control method, wherein the position of the rolling screw is controlled according to the adjustment amount at a position corresponding to each position of the rolled material in the pass. 2. A patent claim characterized in that the position in the current pass corresponding to each position of the rolled material in the previous pass is made to correspond to the rotation angle θ of the rolling roll that rolls the rolled material, and is derived according to the following formula: The feedforward automatic plate thickness control method according to item 1. However, H: Target thickness of the previous pass h: Target thickness of the current pass ffn-1: Advancement rate of the previous pass fn: Advancement rate of the current pass θ1: The thickness of the rolling roll from the biting end of the rolled material in the previous pass Rotation angle θ2: Rotation angle of the rolling roll from the biting end of the rolled material corresponding to the above θ1 in the current pass