JPS6028566B2 - Plate crown control method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a plate crown control method.

The roll pending method in a four-high rolling mill has traditionally been used as a crown control method in plate rolling.
There are limits to the control function, and the lack of capacity is noticeable, especially when the inside of the board changes significantly, making it impossible to obtain sufficient effects.

To solve this problem, a rolling mill has been developed that has a new mechanism in which an intermediate roll is disposed between the reinforcing roll and the work roll, and the intermediate roll is displaced in the axial direction (
(Refer to Publication No. 1951 of 1951). As shown in FIG. 1, this new type of rolling mill uses a pair of axially movable intermediate rolls 3, 3 in addition to the known work roll bender 5, 5'.
', and by moving each roll of this pair of intermediate rolls in the direction of the bag using the moving devices 6, 6', the deformed shape of the work rolls 2, 2' can be greatly changed, resulting in an excellent plate crown control function. It is characterized by having certain characteristics. Note that 1 is the material to be rolled, 4 and 4' are reinforcing rolls, and B
is the inside of the plate, 6 is the amount of deviation between the rolls 3 and 3', and L is the amount of overlap. The gist of the present invention is a new strip crown control method in a rolling mill, in which intermediate rolls are used to obtain a target crown using detected values of the entrance strip crown, the middle strip, the strip thickness, and the exit strip thickness. A plate crown control method characterized by calculating the movement amount and roll pending force, comparing them with an actual detected value, and controlling the movement amount and roll pending force of an intermediate roll based on the comparison signal. It is in.

That is, the method of the present invention uses a rolling mill in which a movable intermediate roll is moved according to the inside of the plate of the material to be rolled, thereby exhibiting remarkable sheet crown control ability for various sheet sizes. The entry side plate crown and rolling load are detected to determine the optimal intermediate roll movement amount and roll pending force, and the intermediate roll movement amount and roll pending force are compared with the detected value of the intermediate roll movement amount and the roll pending force detection value, and the intermediate roll movement amount, This controls the roll bending force.

Embodiments of the present invention will be described below with reference to the drawings. First of all, ``Figure 1 shows a new type of rolling mill that is the basis for carrying out the method of the present invention, and its mechanism and operation are already known and detailed in Japanese Patent Publication No. 50-19510, and its configuration is is as already stated.

FIG. 2 is a graph illustrating the roll pending effect in a rolling mill when implementing the method of the present invention shown in FIG. 1, and shows the relationship between the distance from the center of the sheet and the sheet thickness distribution.
An example is shown in which two types of roll pending force are applied, namely 0 ton/chock (solid line curve) and 50 ton/chock (dashed line curve), for each of the 900 column, 150 gunwale, and 210 aft.

This clearly demonstrates the superiority of the plate crown control ability of the rolling mill used in the method of the present invention compared to the rolling method of the secondary four-high rolling mill. Figure 3 is a graph showing the relationship between roll pending force F and plate crown Cri in the rolling mill used in the method of the present invention, and a, b, c, d, and e in the figure are for the rolling conditions shown in Table 1. .

In this example, the entrance side plate thickness hi-,=5 ribs, and the exit side plate thickness hi=4 sides. From Table 1, it can be seen that there is a linear relationship between the roll pending force F and the plate crown Cri if the rolling load P, the plate center B, and the intermediate roll position 6 are constant.

Therefore, if P, B, and 6 are known, the required plate crown Cri
Find the roll pending force F required to obtain . Fourth
The figure shows the experimental results of the relationship between sheet crown change and shape during hot sheet rolling for the cases where B in the sheet is 914 side and 1543 sail, and the sheet thickness hi is 3 Yanagi and 6 Yanagi, respectively.

In the figure, △docr indicates the difference in elongation in the longitudinal direction between the central part of the plate and the edge of the plate due to changes in the plate crown, △gos indicates the difference in elongation of the same machine determined from the shape, and hi' indicates the plate thickness on the exit side. show. Although it is desirable that the shape of the rolled product be flat, it is clear that, for example, when the product is obtained by multiple rolling passes, the shape does not necessarily need to be flat in the initial pass or intermediate pass. If you try to set the rolling conditions so that the shape is always flat in the initial bath and intermediate passes, you will end up with vertical rolling conditions, which will require a correspondingly large number of rolling passes. The result is undesirable. Furthermore, productivity is significantly reduced due to the large number of passes. In the method of the present invention, for example, a shape that does not interfere with the rolling of the next pass is given as the limit shape ΔS, and the plate crown is changed and controlled. Therefore, in the examples shown in FIGS. 3 and 4, the following formula is used to control the plate crown while taking the plate shape into consideration. △Doq=Q・△DoS…….

)Q=f(B・hi) ……■Cri
=hi〔(...C should be Rani)-△Move+C obi Shozo;...・【
3,F=6・Cri...
■3=g(P・B)...[5' However, in the formula, △goq=difference in elongation due to changes in plate crown△gos=difference in elongation B determined from the shape =h in the plate=thickness Crj=exit side plate Crown Crj-1=Inlet side plate crown hi=Outlet side plate thickness hi-1=Inlet side plate thickness F=Roll bending force P=Rolling load.

Here, by inserting the limit shape △zs〆 into △S of the m formula, the plate crown change exit side plate crown that can obtain the limit shape can be found, and furthermore, the roll pending force F to obtain it can be found. .

Next, the operation of plate crown control in the method of the present invention will be explained with reference to FIG.

The calculator 16 receives the inlet plate crown value Cri- from the plate crown detector 10 for the inlet side, and various information necessary for plate crown control, such as the inlet plate thickness, the outlet plate thickness, and the critical shape △ is used to calculate the exit side plate crown Cri.

Further, the calculating unit 12 calculates the initial value 6o of the intermediate roll movement amount using the inside-board detection value B from the inside-board detector 11.
The computing unit 17 receives the detected value P from the rolling load detector 9, the outlet plate crown Cri from the computing unit 16, and the intermediate roll movement amount 6 from the computing unit 12. The optimal roll pending force Fe is calculated using The adder 18 adds the optimum roll pending force Fo and the detected value F from the roll pending force detector 7 to determine the roll pending force deviation amount ΔF. Roll pending force control device 19
controls the roll pending devices 5, 5' based on the roll pending force deviation amount ΔF. On the other hand, the adder 13 receives the intermediate roll movement amount initial value 6 from the calculator 12.
. and intermediate roll movement amount detectors 8, 8' to arithmetic unit 14.
The deviation amount Δ6 is obtained by adding the detected value 6 of the intermediate roll movement amount inputted through . Intermediate roll movement control device 1
5 controls the intermediate roll moving devices 6, 6' based on the intermediate roll movement deviation amount Δ6 so that it is zero. Since the method of the present invention is constructed and operated as described above, it is a method of controlling the plate crown while considering the allowable plate shape, and can greatly improve product quality yield and productivity, and achieve economical IJt is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a rolling mill used in the method of the present invention, Fig. 2 is a diagram showing the plate crown control ability of the rolling mill used in the method of the present invention, and Fig. 3 is a graph showing the relationship between roll pending force and plate crown. , FIG. 4 is a graph showing the relationship between shape and plate crown change according to the method of the present invention, and FIG. 5 is a block diagram showing an apparatus for carrying out the method of the present invention. 1... Material to be rolled, 2, 2'... Work roll, 3, 3'...
...Intermediate roll, 4,4'..."Reinforcement roll, 5,5'...
... Roll pending device, 6, 6'... Intermediate roll moving device, 7... Roll pending force detector, 8, 8'..." Intermediate roll movement amount detector, 9.
... Load detector, 10 ... Plate crown detector, 11 ... Plate inside detector, 12, 14 ... Arithmetic unit, 1
3... Adder, 15... Intermediate roll movement control device, 16, 17... Arithmetic unit, 18...
... Adder, 19 ... Roll pending force control device. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a rolling mill in which at least one pair of rolls is movable in the axial direction, the intermediate roll movement amount and roll bend are calculated to obtain the target crown using the detected values of the entry side plate crown, plate width, plate thickness, and exit side plate thickness. Calculate the ding force,
A sheet crown control method characterized by comparing these with actual detected values and controlling the movement of an intermediate roll and roll bending force based on the deviation signal.