JPS6123511A - Four-high rolling mill - Google Patents

Abstract

PURPOSE:To carry out effectively shape control and reduction of edge drop by arranging alternately a work roll having a tapered crown at one end of the roll movably in an axial direction body, and incorporating it in a housing together with backing rolls. CONSTITUTION:A crown having tapered grinding areas 4, 5 is formed at one end of the upper and lower work rolls 2, 3 of the roll body. The tapered grinding areas 4, 5, are alternately arranged and mounted movably in an axial direction of the roll, incorporated in a housing stand 18 together with backing rolls 12, 13 to form a r-high rolling mill. By using this rolling mill the thickness deviation of the rolled plate in axial direction is diminished and the edge drop is reduced. Also waving, abnormal projections, etc. can be effectively suppressed. Thus, the work efficiency and basic rolling productivity can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a four-high rolling mill having a novel roll structure, and particularly relates to a four-high rolling mill having a novel roll structure, and in particular, it skillfully combines changes in the width of a rolled plate during rolling with the deformation characteristics of the rolling roll body to improve the rolling strength of the rolled plate. This is intended to advantageously control the shape.

Regarding the shape quality of rolled plate products, as shown in Figure 1,
Waveform deformation (flatness) due to fal waving phenomenon, (
b) Crown due to thickness deviation in the width direction of the remaining part excluding both edges, (C) Edge drop due to peculiar metal flow only at both edges, (d1 Local protrusion (center buildup, edge buildup, etc.) There are four types, all of which require strict restrictions.

In order to prevent waving, suppress crowning, and reduce edge drop in conventional 4-high rolling mills, it is necessary to consistently pay attention to the operation from hot rolling to cold rolling under a detailed rolling schedule. There was no good method, and a roll bending device was used exclusively as a control method, but this was only slightly effective in preventing waving, but had little effect on crown control or edge drop mitigation control. This is the current situation.

In addition, in the 6-high rolling mill, the above-mentioned control is strongly performed by moving the intermediate roll in the axial direction according to the width of the plate to be rolled to reduce the axial deflection deformation of the work roll. , it is completely powerless to prevent local protrusions, and furthermore, it is extremely complicated and difficult to modify a regular 4-high rolling mill to 6-high rolling mills, and it also has the disadvantage of high modification costs. Significant.

In addition, by using a work roll with a so-called trapezoidal crown that has been previously ground IRj17 on both ends of the roll body, crown control and edge drop reduction control are possible, and when this is combined with a roll bending device, the effect can be improved compared to normal. It is larger than the crown work roll and is effective in preventing waving, but if the width of the plate to be rolled changes, the control effect changes accordingly, and as with the 6-high rolling mill mentioned above, local protrusions may be prevented. The problem was that it was not useful for prevention.

In other words, local protrusions such as center build-up and edge build-up occur due to abnormal wear of the work roll, but abnormal wear such as curling occurs at a fixed position in the width direction of the rolled plate, so the work roll This was difficult to avoid with fixed rolling mills. In particular, with edge-built amplifiers, abnormal wear occurs in the tapered grinding area that contacts the edges of the rolled plate, where the temperature drop is greater than in the center and the deformation resistance is higher. This problem tends to occur when rolling of a strip width is continued, but in rolling using trapezoidal crown rolls, it is necessary to keep the width of the rolled strip constant, so the tapered edge of the rolled strip is ground. The contact position in the area is roughly the same, so orders for edge-built amplifiers were even more important.

Furthermore, when the trapezoidal crown roll is used, if the material (hardness) changes, the occurrence of edge build up and edge drop as described above tends to be further promoted.

The present invention completely solves the problems of the prior art as described above, prevents waving of rolled sheets, controls crowns, and furthermore provides more effective edge drop reduction control than conventional methods, and eliminates edge drops even if local protrusions occur. The purpose of this project is to propose a four-high rolling mill that can strongly control shape, such as preventing build-up.

In general, in order to roll the plate so that the thickness distribution in the width direction is uniform, the surface of the work roll in contact with the plate to be rolled must be
It is important that one surface is uniform and the gap between the upper and lower work rolls in the width direction of the sheet is uniform.

Therefore, if rolling is carried out as close to the above conditions as possible, it is possible to produce rolled sheet products with good flatness and excellent cross-sectional shape in the sheet width direction. This method reduces the axial deflection deformation by removing the large excess bending moment that occurs at the body end of the work roll, and also alleviates the sudden change in the amount of flattening deformation of the work roll at both edges of the rolled plate. It is necessary to eliminate metal flow at both edges, and also to eliminate abnormal wear that occurs locally on the work roll.

This invention enables the above-mentioned functions to be applied to rolled plates of any width.

That is, the present invention includes a pair of work rolls each having a crown including a tapered grinding area at one end of a rolling roll barrel, which are stacked one on top of the other in an alternating arrangement at one end, and are movable in the axial direction of the rolls, together with a reinforcing roll. This is a four-high rolling mill characterized by being built into a mill housing.

One end of the body of each upper and lower work roll is tapered and ground.
By arranging the tapered grinding zones alternately, the contact pressure with the reinforcing roll at the body end of the work roll is reduced, and no extra bending moment is applied to the work roll, so the axial deflection deformation of the work roll is reduced. do. Therefore, prevention of waving and crown control can be advantageously performed.

In addition, by moving the upper and lower work rolls according to the width of the plate to be rolled and positioning both edges of the plate to be rolled in the tapered grinding area of each of the upper and lower work rolls, the work rolls and the plate to be rolled are Since the contact pressure with both edges can be reduced and sudden changes in roll flattening deformation at both edges can be alleviated, there is no peculiar metal flow at both edges, and edge drop can be effectively controlled. .

Furthermore, since both the upper and lower work rolls are movable in the axial direction, it is possible to reduce localized abnormal wear, which has been a problem with conventional work rolls, and to advantageously prevent local protrusions.

In other words, center build-up that occurs in the non-tapered grinding area can be avoided by moving the work roll in the axial direction, even if localized abnormal wear occurs on the roll surface. Since it can be dispersed over the entire area, it can be effectively reduced. Regarding edge build-up, as is clear from the examples described later, in this invention, it is not necessary to limit the contact position in the tapered grinding area of the edge of the rolled plate to one point, and there is a certain tolerance range. This can be effectively prevented by appropriately changing the set position of the end portion within the permissible range.

Furthermore, even if the material of the rolled plate changes, the length of the edge of the rolled plate that will be rolled down on the grinding surface will change depending on the material change, for example from a hard one to a soft one. In addition to adjusting the width of the board, fine-tuning the shift amount can effectively prevent the occurrence of edge drop and edge build amplifier. You get it.

The present invention will be described in detail below with reference to examples.

FIG. 2 shows a four-high rolling mill according to the present invention from the front, and in the figure, number 1 is a plate to be rolled, and 2 and 3 are upper and lower work rolls, respectively. In addition, the lower work rolls 2.3 have tapered grinding zones arranged alternately as shown, all of which are pivoted so as to be movable in the direction of the roll axis. 4.5 is above, respectively.
This is a tapered grinding area at the body end of the lower work roll 2.3, and it is desirable that the degree of grinding be the same in both cases. 6.
7 is a hair ring chock for the upper and lower work rolls, and 8.9 is a spindle for the upper and lower work rolls 2 and 3, respectively, which have a spline structure for torque transmission.

Although the device for moving the upper and lower work rolls 2.3 in the roll axis direction is not shown, the work roll bearing chock 6
．． It may be mounted on the periphery of the spindles 7 or on the extensions of the spindles 8 and 9, for example, on the periphery of the gearbox, and the movement method may be hydraulic, electric, or magnetic.

10 is a balance device for the work rolls 2 and 3 or a roll bending device for increasing, and 11 is a roll bending device for decreasing.

12 and 13 are reinforcing rolls for the upper and lower work rolls 2.3, 14.15 is a reinforcing roll chock, 16 is a bearing in the reinforcing roll chock 14.15, 17 is a reduction screw, and 18 is a housing stand. be! .

Although this example shows a work roll drive system, the drive system may be a reinforcing roll drive, and the left-right relationship of the tapered grinding areas of the upper and lower work rolls may be reversed from this example.

Here, the relative position between the work rolls used for rolling and the plate to be rolled and the grinding depth are defined as shown in FIG. 3.

The length of the tapered grinding performed on one end of the body of the work roll in the roll axial direction is constant (50 to 500 mm), and the grinding depth at the body end is set to EHL, and the tapered grinding area and non-tapered grinding of the upper and lower work rolls are different. The length of the edge of the plate to be rolled (effective grinding length) which will be rolled down in the area is expressed as EL.

The effect of controlling the shape of a rolled plate when using the four-high rolling mill according to the present invention will be explained below, in comparison with the cross-sectional shape in the width direction of a rolled plate obtained using a conventional rolling mill.

A rolled plate having a width of 7501 nI11 and a thickness of 3.28 mm was hot rolled to a thickness of 2.3 mm under the rolling conditions (EH, 1, L) shown in Table 1.

FIG. 4 shows the thickness profile of the rolled plate product obtained at this time from the center to the edge in the width direction.

For comparison, the plate thickness profile of a rolled plate product obtained by a conventional method under similar conditions using a normal work roll without tapered grinding is also shown.

As is clear from this figure, the plate thickness deviations in the width direction of the rolled plate products obtained by the present invention are all smaller than those obtained by the conventional method, and the edge drop is also reduced. And as EH and EL become larger, in this example, EH=20011m, [! A particularly excellent cross-sectional shape was obtained when L=150 mm.

Furthermore, no waving or abnormal protrusions were observed.

As described above, the present invention is extremely effective in preventing waving, crown control, edge drop reduction control, and preventing local protrusions, and moreover, the present invention is extremely effective in preventing waving, crown control, edge drop reduction control, and local protrusion prevention. hot finishing rolling mill,
It can be applied to all four-high rolling mills such as cold rolling mills and reverse rolling mills, and modification thereof is easy, so there is no disadvantage of high equipment costs.

In addition, since the wear of the rolls during the rolling process is uniform, the number of coils in one cycle of rolling can be increased more than before, and there is no restriction on the width configuration of the rolled plate at this time, improving work efficiency and roll consumption. Significant improvements can also be achieved.

[Brief explanation of the drawing]

Figure 1 (al, (bl, (C1, (dl) is an explanatory diagram of the abnormal shape of a rolled plate product, respectively. Figure 2 is a front view of a four-high rolling mill according to the present invention. Figure 3 is a work roll and a rolled plate. Figure 4 is a diagram showing the relative position with respect to the plate. Figure 4 is a comparison diagram of the plate thickness profile in the plate width direction of hot rolled plate products obtained by the present invention and the conventional method. ■... Rolled plate 2.3...Upper and lower work rolls 4.5...Tapered grinding area 6.7...Bearing chocks for upper and lower work rolls 8
．． 9... Spindle 10... Balance device or increase roll bending device 11... Decrease roll bending device 12,
13... Reinforcement rolls 14, 15... Reinforcement roll chock 16... Bearing 17... Reduction screw 18... Housing stand Fig. 1 (a) (b) (d) f: vl/- Build Ala7・Fcihild γ17- Figure 2!

Claims (1)

[Claims] 1. A pair of work rolls having a crown including a tapered grinding area at one end of the rolling roll barrel are stacked vertically in an alternating arrangement on one end and are movable in the roll axis direction, and are incorporated into the mill housing together with a reinforcing roll. A four-high rolling mill characterized by the fact that