JPH044043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of a multi-stage cluster rolling mill,
In particular, the present invention relates to a multi-stage cluster type rolling mill that prevents the occurrence of roll marks on rolled materials.

In recent years, in order to improve productivity and save energy, there is a need for high-reduction rolling mills that can significantly reduce plate thickness in a single rolling process, as well as stricter requirements for processing accuracy in plate thickness and shape. There is.
There is a multi-stage cluster type rolling mill that enables this high reduction rolling.

As shown in FIG. 1, this multi-stage cluster rolling mill has an upper roll group and a lower roll group arranged vertically symmetrically with a material 1 to be rolled in between.

The upper roll group and the lower roll group are work rolls 2a and 2b that linearly roll the material 1 to be rolled,
Consisting of a set of two intermediate rolls 3a, 3b that support the work rolls 2a, 2b, and reinforcing rolls 4a, 4b; 5a, 5b that support the intermediate rolls 3a, 3b, the reinforcing rolls 4a, 4b; 5a, 5b A in Fig. 1 is used to control the shape according to the rolling conditions.
As shown in FIG. 2, which is a sectional view taken along arrow -A, it is divided into a plurality of parts in the axial direction and rotatably supported by one shaft 6.

The rolled material 1 is fed between the work rolls 2a and 2b from the direction of the arrow in FIG. work roll 2
a and 2b and sent outward.
In this type of rolling, the contact surfaces of the intermediate rolls 3a, 3b that are in contact with the upper and lower reinforcing rolls 4a, 5a; 4b, 5b have a contact surface pressure between the rolls, as shown in FIG. , are concentrated at both ends of each divided cylindrical reinforcing roll, and when the rolling mill is operated for a long time, the respective intermediate rolls 3a,
A striped roll mark 7 is generated on the outer peripheral surface of the roll 3b at the contact portion with both ends of each split reinforcing roll (see Fig. 2), and this roll mark 7 also extends to the work rolls 2a and 2b. Furthermore, the rolled material 1 has the disadvantage that it has streak-like scratches and differences in gloss, that is, roll marks, which significantly reduce the quality of the product.

In order to eliminate such drawbacks, the present applicant proposed in Japanese Patent Application No. 135206/1983 that a motor 10 is driven to move two slides in a set on a sliding table 9 fixed to a frame 8, as shown in FIG. Shift the left and right intermediate rolls 3a in mutually opposite axial directions, and
It has been proposed that the lower intermediate rolls of the set should also be shifted in mutually opposite axial directions from the upper intermediate rolls.

However, even in this rolling method, if the intermediate roll shift speed is increased, a large shift force is required, and unless the thrust force is increased, the roll shift force device will not work, making it difficult to prevent the occurrence of roll marks. be.

In view of these circumstances, the inventor of the present invention conducted a pilot experiment regarding the relationship between the shift speed and thrust force of the intermediate roll, and found that by decreasing the ratio of shift speed/roll circumferential speed, the thrust force becomes smaller, and by decreasing the speed. In order to ensure that the thrust force during shifting falls within the allowable values for preventing the occurrence of roll marks, allowable upper limits are set for each of the shift speed and thrust force (hereinafter referred to as "set values") for shift operations. ), and discovered that even when external conditions such as rolling force and friction coefficient change, it is sufficient to maintain the correlation between the two and shift the shift under satisfactory conditions, thereby completing the present invention. did it.

That is, an object of the present invention is to provide a multi-stage cluster type rolling mill that prevents the occurrence of roll marks on rolled material.

A multi-stage cluster rolling mill of the present invention that achieves the above object includes a pair of upper and lower work rolls, a pair of upper and lower intermediate rolls that support each work roll, and a pair of upper and lower intermediate rolls that support the upper and lower intermediate rolls. A multi-stage cluster rolling mill comprising a plurality of upper and lower reinforcing rolls, the reinforcing rolls being divided into a plurality of pieces in the longitudinal direction, and the left and right middle rolls being able to shift in opposite axial directions. A shift force measuring device, a shift speed measuring device, a roll circumferential speed measuring device and a rolling load measuring device are provided to measure the moving speed, shift force, roll circumferential speed and inter-roll load of the shiftable intermediate roll, and these A controller is installed to operate the shift force and inter-roll load ratio at 0.06 or less by calculating and comparing the signals from the measuring instruments and keeping the ratio of shift speed and roll circumferential speed at 2.0×10 ^-4 or less. It is characterized by:

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the multi-stage cluster type rolling mill of the present invention will be described in detail.

FIG. 5 shows a sectional view of essential parts of a multi-stage thruster type rolling mill according to the present invention.

The configuration of this rolling mill is basically the same as the conventional multi-stage cluster rolling mill shown in FIG.
a, 2b, and a set of two intermediate rolls 3a, 3b that support each work roll 2a, 2b, respectively.
A plurality of back-up rolls, that is, reinforcing rolls 4a and 5, support the intermediate rolls 3a and 3b, respectively.
a; It consists of 4b and 5b, and the reinforcing roll 4
a, 5a; 4b, 5b are divided into a plurality of parts in the axial direction, and are rotatably attached to roll shafts 6a, 6b. All of the reinforcing rolls do not need to be split rolls, and all of the central reinforcing rolls do not have to be split rolls, and only the central reinforcing rolls 5a and 5b may be of the split type. The intermediate rolls 3a, 3b are connected to rack slides 9a, 9b and pinions 10a, 1 through shaft joints, respectively.
0b, and can be shifted in the directions of shafts 6a and 6b by drive motors 11a and 11b, respectively, and is rotatably mounted. During rolling, the upper intermediate rolls 3a and 3b and the lower intermediate rolls 3b and 3c are shifted in opposite directions.

Further, the roll shafts 6a, 6b are provided with shift force measuring devices 12a, 12b; roll circumferential speed measuring devices 13a, 13b; shift speed measuring devices 14a, 1.
4b is provided. Here, as an example, each measuring device is provided on the roll shafts 6a and 6b, but a shift device and a drive device may be provided respectively. The rolling load measuring device was a normal rolling load cell, and the inter-roll load was calculated from this rolling load. These shift force measuring instruments 1
2a, 12b; Roll circumferential speed measuring device 13a, 13
Roll shift speed measuring devices 14a, 14 among b.
Output 12 produced at b and inter-roll load output 1
2' as shown in FIG.
5 and calculate the value of shift force/load between rolls,
The obtained electrical output is compared with the electrical output of a set value 17, which will be described later, in the comparison circuit 16, and if the output exceeds the allowable value, that output is supplied to the controller 18. On the other hand, the electric output 14,1 is proportional to the output obtained from the shift speed measuring device and the roll circumferential speed measuring device.
3 are respectively supplied to the divider circuit 19, which calculates the ratio of shift speed/roll circumferential speed, and sends the output to the comparator circuit 20, which compares the output of the set value 21, and outputs exceeding the allowable value are sent to the controller 18. sent to. In the controller 18, the comparison circuits 16 and 2
According to the electrical output sent from 0, an electrical signal is sent to the shift drive motors 11a, 11b and a roll drive motor (not shown), and the shift speed, inter-roll load, and/or roll circumferential speed are adjusted within the allowable range. The upper limit of the allowable shift speed/roll peripheral speed ratio is 2.0×
10 ^-4 , and the upper limit of the allowable shift force/roll load ratio is 0.06.

The relationship between the above shift speed/roll circumferential speed ratio and shift force/roll load ratio is as follows from pilot experiment: Roll load P=20, 50tf Roll circumferential speed v _R =10, 50m/min Shift speed v _S =0.1 ~25 m/min, the characteristic curve shown in FIG. 7 is obtained. Shift force/
The load ratio between rolls is the theoretical formula for the thrust coefficient μ _T when the rolls are crossed. The calculation was made according to the following. In the case of the present invention, the rolls do not cross, but the cross angle (rad) and shift speed/
It was applied assuming that the roll circumferential speed ratios are vector-wise equivalent.

However, μ ₀ = coefficient of friction between rolls, P _R = load between rolls (tf), l = roll barrel length (mm), R = equivalent roll diameter (mm), ν = Boisson's ratio, G = lateral side of roll material The elastic modulus (Kg/cm ² ) is.

From the characteristic diagram in Figure 7, when the shift speed/roll circumferential speed ratio is 2.0×10 ^-4 or less and the shift force P _S /roll inter-roll load P _R ratio is 0.06 or less, there is a linear relationship between the two, and within this range When exceeding the thrust coefficient (
P _S /P _R ) almost reaches a saturation value, and the correlation between the two is lost.

According to experimental results, it has been found that the above relationship holds true not only in the above numerical range but also in general.

Therefore, according to the multistage cluster type rolling mill of the present invention, a shift force measuring device, a shift speed measuring device, a roll circumferential speed measuring device, and a rolling load measuring device are provided, and control is performed to calculate and compare the signals of these measuring devices. The ratio of shift speed and roll peripheral speed is set to 2.0×10 ^-4
In the following, the ratio of shift force and inter-roll load is 0.06 or less, so roll marks are generated on the rolled material by shifting the intermediate rolls with an appropriate thrust force for mechanical strength and at an appropriate shift speed. A rolled product with good surface quality can be obtained without causing any damage.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of main parts showing the arrangement positions of rolls in a multi-stage cluster rolling mill, and FIG. 2 is a cross-sectional view of a main part of the multi-stage cluster rolling mill in FIG.
3 is a sectional view of the main part in the direction of arrow A, FIG. 3 is a characteristic diagram showing the relationship between the axial direction of the reinforcing roll and the contact surface pressure between the rolls during roll rotation of the multi-stage cluster rolling mill shown in FIG. 2, and FIG. FIG. 2 is a cross-sectional view of the main part (upper part) of the improved rolling mill shown in FIG. FIG. 7 is a block diagram of the roll drive circuit of the present invention, and FIG. 7 shows the shift speed of intermediate rolls/load ratio between rolls vs.
FIG. 3 is a characteristic diagram showing the relationship with the roll circumferential speed ratio. In the drawing, 2a, 2b are work rolls, 3a, 3
b is an intermediate roll, 4a, 4b, 5a, 5b are reinforcing rolls, 6a, 6b are roll shafts, 9a, 9b are easy sliding stands, 10a, 10b are pinions, 11
a, 11b are shift drive motors, 12a, 12b
1 is a shift force measuring device, 13a and 13b are roll circumferential speed measuring devices, and 14a and 14b are shift speed measuring devices.

Claims (1)

[Claims] 1. A pair of upper and lower work rolls, and a set of two upper and lower intermediate rolls that support each work roll,
It consists of a plurality of upper and lower reinforcing rolls each supporting upper and lower intermediate rolls, and the reinforcing rolls are divided into a plurality of pieces in the longitudinal direction, while the left and right intermediate rolls are arranged in opposite axial directions. A shift force measuring device, a shift speed measuring device, and a roll circumferential speed measuring device capable of measuring the moving speed, shift force, roll circumferential speed, and inter-roll load of the shiftable intermediate roll in a shiftable multi-stage cluster rolling mill. and a rolling load measuring device, the signals from these measuring devices are calculated and compared, and the ratio of the shift speed to the roll circumferential speed is set to 2.0×10 ^-4 or less, thereby reducing the ratio of the shift force to the load between the rolls to 0.06. A multi-stage cluster rolling mill characterized in that it is equipped with a controller so as to operate as follows.