JPS61140303A - Tandem mill installation - Google Patents

Abstract

PURPOSE:To reduce a rolling power and to obtain an excellent sheet shape by arranging one or more 6-high mills, having intermediate rolls and work rolls made smaller in diam. than the former rolls, at the front and rear stages of a tandem rolling installation, respectively. CONSTITUTION:In a tandem rolling installation consisting of six stands, for instance, rolling mills different from the mills of other stands are arranged at No.1 and No.6 stands. Each of these mills can move its intermediate rolls 18, 20 in the mutually opposite directions 22, 24 along the axial lines as well as can provide bending forces to the rolls 18, 20. Further, each of work rolls 10, 12 has a roll diam. Dw<= the maximum sheet width BmaxX0.3 of a rolling stock and can provide a bending force 26. On the other hand, the mills at No.2-No.% stands have each Dw>=0.3 Bmax, and are equal to said mills in other points except they can not provide forces 28 to the rolls 18, 20. In this way, a high rolling reduction can be applied at the front stage while maintaining the excellent shape of rolling stock, and the rolling power can be reduced as well as the control of further accurate sheet-shape can be performed at the rear stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a tandem rolling apparatus that rolls a material to be rolled by arranging a plurality of rolling mills in series in the traveling direction of the material to be rolled.

[Background of the invention]

In recent years, with the aim of increasing the material base and improving productivity in hot rolling and 112-washing, high reduction rolling has been desired in hot tandem rolling as well as in the stand before cold tandem rolling. There is.

This is because the pressure reduction load pt- can be reduced by lowering the pressure to a high level while the deformation resistance is small. In other words, the relationship between rolling load P, deformation resistance k II and rolling reduction amount Δh is as follows:
The relationship is as follows.

Here, B is the plate width, and Dw is the work roll diameter.

Further, the deformation resistance is expressed as in the following equation.

k-2kmt (1000ε)
・・・(2)m=25kgy ・・・・・・
・・・・・・・・・・・・G) Here, SKA & is the static restraint deformation resistance, and 6 is the strain rate.

For the static restraint deformation resistance, there is a difference of 5U between t and the total reduction rate r.
Taking S304 as an example, the relationship is as shown in FIG. Therefore, it is possible to reduce the rolling load Pt by increasing the rolling reduction amount Δh while the deformation resistance is small, that is, while the static restraint deformation resistance K m t is small.

Moreover, by increasing the amount of processing at one time, the grain size of the material to be rolled can be made finer, and the strength of the material can also be improved.

However, in the first stand of the tandem rolling mill, the conventional 4
If a high rolling mill is arranged to achieve high rolling reduction, the plate crown will be 6 large as shown in FIG. 6(a). Moreover, the plate shape is
As the length of the plate end increases, the edge drop lid δ also increases. For this reason, in conventional 4-high rolling mills, it is not possible to achieve high rolling reduction while maintaining good plate shape. For example, the rolling reduction ratio in each rolling mill of a 6-stand tandem rolling machine is shown by the solid line in Figure 7. It was 30-37.51.

To solve this problem, a six-high rolling mill as shown in Fig. 8(a) was invented (Patent No. 952086). This six-high rolling mill has a pair of intermediate rolls 18.2 between a pair of upper and lower work rolls 10.12 and a pair of upper and lower reinforcing rolls 14, 16.
0, the intermediate rolls 18.20 are displaced axially in opposite directions relative to each other as shown by the arrows 22.24, and a bending force is applied to the rolls 10.12 as shown by the arrows 26. This makes it possible to control the shape and plate crown. By applying this 6-high rolling mill, the rolling reduction ratio in the first stage of the above-mentioned 6-stand tandem rolling machine can be rolled to 50 yen while maintaining a good shape as shown by the broken line in Fig. 7. is possible.

Furthermore, as shown in the above-mentioned equation (1), the rolling load P may be kept at 81 degrees, the same as in the conventional case, even if the working coil diameter Dv is made small and the LD and rolling reduction amount Δh are increased. Also, in edge drop, the effect of the axial movement of the intermediate roll 18.22 and the work roll 10. By making the diameter smaller, the cost was reduced, leading to an improvement in yield.

However, the needs of the rolling industry are aimed at further improving productivity and improving edge drop, and in order to meet these needs, it has become necessary to reduce the diameter of work rolls. When the work roll diameter of the six-high rolling mill mentioned above is reduced, the plate becomes a crown as shown in Fig. 148), and the plate shape also becomes a so-called quarter buckle, which allows high rolling while maintaining a good shape. becomes impossible.

As a result, in the 6-high rolling mill shown in Fig. 8(a), Dw <0.3 for the large plate width B118 of the rolled material.
B,-! When it reaches a certain level, it becomes an overbuckle-like double crown as shown in FIG. 6(b). In addition, this compound fire is under high pressure, so it is a compound fire.
Subsequent corrections at valley stands are difficult. on the other hand,
In the latter stage of a tandem rolling mill, emphasis is placed on shape control, and particularly in the field of cold rolling, it is essential for a rolling mill to have the ability to correct quarter buckles using a thermal crown.

[Object of the Invention] The present invention provides a tandem rolling apparatus that can reduce rolling power and obtain a good plate shape.

The purpose is to

[Summary of the invention]

The present invention enables intermediate rolls to move in mutually opposite directions along the axis of at least one of the front stages and at least one of the rear stages of a tandem rolling machine, and also applies bending force to the intermediate rolls and the work rolls. Nine rolling mills were installed, and the first stage was able to maintain a good plate shape while reducing rolling power, reducing the rolling power, and the second stage was able to control the shape of the plate with even higher precision. It is composed of

[Embodiments of the invention]

A preferred embodiment of the tandem rolling apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are superimposed on the parts corresponding to those explained in the above-mentioned prior art, and the explanation thereof will be omitted.

FIG. 1 shows a rolling mill arrangement of an embodiment of a tandem rolling apparatus according to the present invention. The tandem rolling apparatus shown in FIG. 1 is a 6-stand tandem rolling apparatus, and the rolling mills shown in FIG. 2 are arranged in the first stage and the final stage, that is, the rolling stand and the rolling stand. This rolling machine is
As shown by the arrow 22.24, the intermediate roll 18.20
It is possible to move in mutually opposite directions along the axis and to apply a bending force to the intermediate rolls 18, 20 by a bending device, not shown, as indicated by arrow 28.

Further, the work roll 10.12 has a work roll diameter Dw≦0.
．． 3B, ..., and can apply a bending force as shown by an arrow 26 by a bending device (not shown).

Stands A2 to &5 are provided with the rolling mills shown in FIG. 8 above. That is, the rolling mills of stands 2 to A5 have Dw≧0-3B, and the work roll 10
．． 12 by adding bending power. However, no bending device for the intermediate roll 18,20 is provided, only a shifting device that can move in mutually opposite directions along the axis.

In the embodiment configured as described above, even if the diameter of the work roll is made small and the pressure is reduced at a high pressure in one stand, the plate cracks as shown in FIG. 6(C), and a good plate shape can be maintained. At the same time, the structure can be made finer and the edge drop amount δ can be reduced. Moreover, &
For rolling in one stand, the diameter of the work roll is reduced,
The rolling reduction ratio can be increased with the same rolling power as in the conventional method. As a result, the rolling power of the entire tandem rolling apparatus can be made smaller than before.

However, as the rolling time elapses, the body of the work roll expands due to plastic working heat and frictional heat caused by rolling, that is, thermal crown occurs.

For this reason, if rolling is continued in a state where a thermal crown has occurred, the sheet crown will become overbuckled as shown in FIG. 3, deteriorating product quality. Therefore, in order to obtain a good plate shape of the rolled material, it is necessary to correct the quarter buckle at the downstream stage of the tandem rolling device, and a rolling mill suitable for this must be arranged. A rolling mill capable of correcting the quarter buckle shown in FIG. 3 needs to be a rolling mill in which the work rolls are deflected in a 6th order curve that can offset the cracks that cause the quarter buckle. Therefore, when we investigated the plate crown control characteristics of various rolling mills, we found the results as shown in FIG. Figure 4(a)
is the plate clarification/control characteristic of a four-high rolling mill. Also the fourth
FIG. 8(b) shows the plate crown control characteristics of the six-high rolling mill shown in FIG. 8(a), in which Dw≧0.3B, . . . and the working roll diameter is relatively large. Figure 4 (C) is
FIG. 2(a) shows plate crown control characteristics of a six-high rolling mill in which the intermediate Ω-rule can be shifted in the axial direction and can apply bending force. As is clear from the strip crown control characteristics of each of these rolling mills, the rolling mill having the strip crown control characteristics shown in FIG. It is a machine.

Therefore, by arranging the rolling mill shown in Fig. 2 (a) on the A6 stand in the tandem rolling machine shown in Fig. 1, a good plate shape can be obtained, and the plate shape can be precisely controlled. It can be carried out. As a result, the amount of edge drops is also reduced, and the yield can be improved.

In the above embodiment, the case was explained in which the rolling mill shown in FIG. 2 was applied to the Al stand and the A6 stand. Other pressure machines for skinship may be placed in 166 Untando. Furthermore, in the above embodiments, a 6-stand tandem rolling machine has been described, but the present invention is not limited to a 6-stand tandem rolling machine.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce the rolling power and obtain an attractive plate shape.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a rolling mill arrangement of a tandem rolling apparatus according to an embodiment of the present invention, and FIG. 2 is an A I diagram of g1. 46 is a detailed explanatory diagram of the rolling mill and a diagram showing the plate crown, Figure 3 is a diagram showing the plate crown due to the thermal crown of the work roll, Figure 4 is a plate crown control characteristic diagram of various rolling mills, and Figure 5 is a diagram showing the plate crown in 5US304. Figure 6 is a diagram showing the relationship between total rolling reduction and static restraint deformation resistance. Figure 6 is a diagram showing the crown of the plate after high reduction by applying various rolling mills to the first stand of a tandem rolling edge device. Figure 7 is a diagram showing the relationship between the total rolling reduction rate and static restraint deformation resistance. Figure 8 shows the sheet thickness reduction curves for a 6-stand tandem rolling mill using a 4-high rolling mill and a 6-stand tandem rolling mill using a 6-high rolling mill. FIG. 2 is a diagram showing the configuration of a flattening machine for controlling the cutting edge and the plate crown. 10.12...Work roll, 14.16...Reinforcement roll, 18.20...Intermediate roll.

Claims (1)

[Claims] 1. In a tandem rolling device that continuously rolls a material to be rolled in multiple stages using a plurality of rolling mills arranged in series, at least one of the front and rear rolling mills is rotatably supported by a housing. A pair of work rolls, a work roll bending means that applies bending force to these work rolls, a pair of intermediate rolls rotatably disposed in contact with the outside of the pair of work rolls, and an axis line of the pair of intermediate rolls. intermediate roll shifting means for moving in mutually opposite directions along the pair of intermediate rolls; intermediate roll bending means for applying bending force to the pair of intermediate rolls; and a pair of intermediate rolls rotatably disposed in contact with the outside of the pair of intermediate rolls. A tandem rolling device characterized by having a reinforcing roll.