JPS583764B2 - Lockon level stabilization method - Google Patents

Description

[Detailed description of the invention] This invention is based on the lock-on level (target plate thickness) for each rolling pass.
The present invention relates to a lock-on level stabilization method that allows the lock-on level to be set based on the lock-on level in the previous pass.

Plate thickness control using the lock-on method is based on 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, and the outlet thickness hO at that time is determined as follows. Then, the target plate thickness for that pass is set to the plate thickness hO.

This lock-on method has the following problems.

To explain this point with reference to the characteristic diagram in Figure 1,
At the lock-on in the second bath, the exit side plate thickness hot at the intersection point Po 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 △H1, the exit side plate thickness variation △h1
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. The intersection of the plastic curve 105 and the elastic characteristic curve 104 does not result in h02, but ho
2+Δh21.

Or, if the entry side plate thickness variation △H2 is added, the plasticity curve 106
h02+△h21 by the intersection of and the elastic characteristic curve 104
+Δh22.

In this way, it is preferable for the lock-on level to differ for each pass in terms of product accuracy.

Furthermore, it is undesirable from the standpoint of rolling efficiency that the lock-on value of the previous pass is not equal to the entrance plate thickness of the current pass.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method that can eliminate the errors inherent in the lock-on method.

FIG. 2 is a block diagram embodying an embodiment of the lock-on level constantization 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 reduction screw, 6 is a load cell that detects the rolling load F, and 7 is an arithmetic unit that corresponds to the target plate thickness of the lock-on corrected by the elongation lock-on level correction device 11 of the rolling mill. It is stored as the elongation of the rolling mill.

9 leads to locked on with comparator.

10 is an arithmetic unit that derives the plate thickness variation ΔH at the tail end of the previous pass (the leading end in the current pass) using the following equation.

ΔF: Deviation between rolling pressure during lock-on and rolling force during rolling M: Mill constant △S: Amount of movement of the reduction screw from the position of the reduction screw during lock-on △H: Amount of variation from the target plate thickness 11 is the deviation from the target plate thickness The value of the following equation is obtained from ΔH obtained by the equation (1) K in the level correction device and is led to the comparator 12.

In this case, it is assumed that the position where the plate thickness variation ΔH is located is the same as the lock-on position.

Q: Deformation resistance of rolled material, that is, the lock-on memory 8 calculates the following equation and stores the value.

The amount of screw pressure movement △S is detected from .

In the above configuration, the operation will be explained with reference to FIG. 8. If there is a variation ΔH' in the thickness of the inlet side at the tail end of the previous pass (the tip of the current pass), the exit side plate of ΔH will change as shown in FIG. Causes thickness variation.

The exit plate thickness variation ΔH is expressed by the following equation from equation (1).

Furthermore, if there is a change in the entrance side plate thickness ΔH at the tip of the rolled material in the current pass, the exit side plate thickness variation Δh is expressed by equation (2).

becomes.

Therefore, in the current pass, the rolling force is stored in the correction field 8 by the lock-on level correction device 11.

Crew reduction movement amount △S in rolling in this pass
, and drive the reduction screw.

Although the above explanation has been made on the assumption that a reversible rolling mill rolls a rolled material many times with a single rolling mill, it is also applicable to a tandem rolling mill.

As described above, according to the present invention, the variation amount ΔH from the target plate thickness at lock-on in the previous pass is calculated based on the rolling force at the lock-on position in the current pass.
Since the plate thickness is controlled by lock-on control by correcting the deformation resistance Q of the rolled material and the mill constant M, the error in each pass is small and the plate thickness accuracy can be improved.

It also leads to increasing rolling efficiency.

[Brief explanation of drawings]

1 and 3 are characteristic diagrams of plate thickness and rolling force, and FIG. 2 is a block diagram embodying an embodiment of the lock-on level constantization method of the present invention. 1 is a rolled material, 2 is a work roll, 3 is a reduction screw,
4 is a screw-down screw position detector, 5 is a screw drive device, 6 is a load cell, 7 and 10 are computing units, 8 is a lock-on memory, 9 and 12 are comparators, and 11 is a lock-on level correction device.

Claims (1)

[Claims] 1 From the rolling force variation ΔF1 from the rolling force F0 at the lock-on position in the previous pass and the screw reduction position variation ΔS1 from the screw reduction position at the lock-on position in the previous pass, calculate the plate thickness from the target plate thickness at the lock-on position in the previous pass. A method for stabilizing the lock-on level as a sign of the lock-on position in a lock-on method with fluctuations.