JPH0783881B2 - Steel strip rolling method with quadruple rolling mill - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for rolling a steel strip by a quadruple rolling mill provided with a backup roll having a taper piston type variable roll crown mechanism.

[Prior Art] For example, a thin steel strip used for tinplate has a high flatness in terms of quality in order to satisfy the quality level required for tinplate and to improve the sheet passing property to increase the production efficiency. Is required. Shape-controlled rolling is performed to increase the flatness of the thin steel strip. As the method, a roll crown variable mechanism that makes the roll crown of the work roll variable is provided in the rolling mill, and thereby the roll crown of the work roll is changed to control the flatness of the thin steel strip. I said).

As one of the methods for performing the shape-controlled rolling of the thin steel strip described above, there is a method using a quadruple rolling mill provided with a backup roll having a taper piston type variable roll couran mechanism. The backup roll used in this method has a structure as shown in FIG. That is, the backup roll 31 is located at both ends of the arbor 32, the sleeve 33 shrink-fitted to the arbor 32, and the arbor 32.
And a tapered piston 35 arranged in a hydraulic chamber 34 constituted by a sleeve 33. More specifically, this backup roll 31 is provided with a hydraulic oil supply passage 36 in the arbor 32, and a taper piston is provided through a rotary joint 37 arranged at the shaft end of the arbor 32.
The hydraulic oil for operating 35 is sent from the hydraulic oil unit 38 to the hydraulic chamber 34, and the taper piston 35 is taken in and out in the roll axial direction. A slip ring 39 is provided at the other shaft end of the arbor 32, and
A piston position sensor 40 is provided in 34.
Then, the position signal of the piston position sensor 40 is transmitted by the arbor 32.
It is designed to be sent to the taper piston control panel 42 via the piston position sensor signal line 41 and slip ring 39 provided on the rolling mill operator. The taper piston control is performed.

FIG. 3 shows a grinding procedure of the backup roll 31 equipped with the taper piston 35. First, as shown in FIG. 3 (a), the taper piston 35 is pushed in by the hydraulic oil in the direction of the center of the roll shaft, and the backup roll 31 is deformed into a ridge shape. Next, the roll surface is ground in this state to form a flat surface as shown in FIG. 3 (b). Then, as shown in FIG. 3 (c), the tapered piston 35 is pulled out to the outside of the roll axis so that a convex crown is formed on the surface of the roll.

Fig. 4 shows the backup roll ground in this way.
When the shape of the thin steel strip 44 is controlled by using 31, the relationship between the position of the taper piston 35 in the roll axial direction and the roll profile, the profile of the work roll 45, and the plate shape is shown.

(1) When the taper piston 35 is located on the outermost side from the roll center as shown in FIG. 4 (a), the backup roll profile (51) is in the most convex state, and the work roll profile (52) is the convex crown. , The plate shape (53) is in a state of middle stretch.

(2) When the taper piston 35 is in the intermediate position as shown in Fig. 4 (b), the backup roll profile (5
1) has a slightly convex profile, the work roll profile (52) is flat, and the plate shape (53) is also flat.

(3) When the taper piston 35 is pushed most toward the roll center as shown in FIG. 4 (c), the backup roll profile (51) becomes a flat profile and the work roll profile (52) becomes a concave crown. The plate shape (53) is in the state of an ear wave.

[Problems to be Solved by the Invention] However, in the conventional method of rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism, a backup roll is used as shown in FIG. The length L of the backup roll is designed to be shorter than the length 1 of the work roll.
31a of both ends of the body of 31 and 45a of both ends of the body of the work roll 45
However, the following problems occurred. That is, as shown in FIGS. 6A to 6C, the roll profile of the backup work roll 45 changes to a convex profile as shown in the relationship of changes in the roll profile of the lower work roll 45 with changes in the roll profile of the lower backup roll 31. Then, the following phenomena will occur. That is, when the lower backup roll 31 is in the flat profile (taper piston pushing state) as shown in FIG. 6 (a), the lower work roll 45 also has the flat profile, but as shown in FIG. 6 (b), the lower backup roll 31 is in the flat profile. When 31 has a slightly convex profile, the lower work roll 45 also has a slightly convex profile, and the lower backup roll 31 and the lower work roll 45 are in close contact with each other over the entire body. However, when the lower backup roll 31 has a larger convex profile, the lower backup roll profile has concave profiles 54 at both ends of the roll as shown in FIG. The 31 and the lower work roll 45 are not in close contact with each other over the entire body, but only in the center 55 of the body and both ends 31a of the lower backup roll 31. And especially both ends 31a of the lower backup roll 31
Since concentrated load is applied to the part where both ends 45a of the lower work roll 45 and the lower work roll 45 are in contact with each other, roll flaws may occur in the steel strip,
There is a problem that spoiling occurs on the roll and that the shape of the steel strip cannot be smoothly controlled. 7th
The figure is a graph showing the state in which concave crowns are partially formed at both ends of the backup roll described above, in relation to the pushing amount of the taper piston.

The present invention solves the above-mentioned problems of the prior art,
A quadruple type equipped with a backup roll having a taper piston type variable roll crown mechanism that can smoothly control the shape of the steel strip without causing roll flaws on the steel strip or spoiling on the roll. An object of the present invention is to provide a steel strip rolling method using a rolling mill.

[Means for Solving the Problems] A method for rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism according to the present invention has a taper piston type variable roll crown mechanism. A method of rolling a steel strip by a quadruple rolling mill equipped with a backup roll, characterized in that the length of the body is longer than the length of the work roll body, and the shape is controlled using a backup roll. This is a method of rolling a steel strip.

[Operation] A method of rolling a steel strip by a quadruple rolling mill provided with a backup roll having a taper piston type variable roll crown mechanism according to the present invention includes a backup roll having a taper piston type variable roll crown mechanism. In the method of rolling a steel strip with a heavy rolling mill, a backup roll having a body longer than a work roll body is used. Therefore, even if the roll profile of the backup roll becomes a convex profile, the both ends of the backup roll do not hit the both ends of the work roll strongly, and the backup roll and the work roll are in close contact with each other over the entire length of the body portion. There is no problem that roll defects occur on the steel strip, spoiling occurs on the roll, and the shape control of the steel strip cannot be performed smoothly.

This action has almost the same effect even if the taper piston type variable roll crown mechanism is symmetrical with respect to the upper and lower points only at one end.

[Embodiment] A method for rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism according to an embodiment of the present invention will be described with reference to FIG. Figure 1 shows the work rolls 1a and 1b of this quadruple rolling mill.
FIG. 3 is a vertical sectional view of backup rolls 2a and 2b. The upper backup roll 2a and the lower backup roll 2b arranged on the upper work roll 1a are composed of an arbor 3 and a sleeve 4 shrink-fitted to the arbor 3. And
At the positions located at both ends of the arbor 3, hydraulic chambers 5 and 6 are formed by the arbor 3 and the recesses provided in the sleeve 4, and a tapered piston 7 is arranged between the hydraulic chambers 5 and 6. The wall surfaces of the hydraulic chambers 5 and 6 are provided with a taper. When the taper piston 7 is hydraulically pushed into the hydraulic chamber 5 and pushed in the center of the roll, the sleeve of the sleeve 4 on the side where the taper piston 7 is arranged is arranged. The outer diameter is configured to be larger than the outer diameter of the indentation by about 1,500μ at the outermost end. And back roll
The body length L of 2a, 2b is configured to be longer than the body length 1 of the work rolls 1a, 1b.

A quadruple rolling mill used in a method for rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism according to one embodiment of the present invention is configured as described above. Therefore, even if the taper piston is pulled out toward both ends of the body and the roll profile of the backup roll is used as a convex crown, both ends of the backup roll do not hit the both ends of the work roll strongly, and the backup roll and the work roll are Since they are in close contact with each other over the entire length, there is no possibility that roll flaws occur in the steel strip, spalling occurs in the roll, and the shape control of the steel strip cannot be performed smoothly.

The present invention is also applicable to hot rolling.

EFFECTS OF THE INVENTION According to the present invention, when a steel strip is rolled by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism, a roll flaw is generated in the steel strip or spalling is caused on the roll. It will not occur, and the shape control of the steel strip can be performed smoothly.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a quadruple rolling mill used in a method for rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism according to an embodiment of the present invention, FIG. 2 is a vertical sectional view of a backup roll having a conventional taper piston type variable roll crown mechanism, and FIG. 3 is an explanatory view showing a grinding procedure of a backup roll having a conventional taper piston type variable roll crown mechanism, and FIG. Is an explanatory view for explaining shape control rolling by a quadruple rolling mill equipped with a conventional backup roll having a taper piston type variable roll crown mechanism, and FIG. 5 shows a backup roll having a conventional taper piston type variable roll crown mechanism. Explanatory drawing which shows the relationship between the work roll of the equipped quadruple rolling mill and the body length of a backup roll, 6th Explanatory view showing a change in contact status of the backup roll and the work rolls due to changes in the size of the backup roll crown, FIG. 7 is a graph showing the relationship between the pushing amount and the backup roll profile of the tapered piston. 1a, 1b ... work roll, 2a, 2b ... backup roll, 3
… Arbor, 4… Sleeve, 5,6… Hydraulic chamber, 7… Tapered piston.

 ─────────────────────────────────────────────────── ─── Continued Front Page (56) References Japanese Patent Publication Sho 60-36322 (JP, B2)

Claims (1)

[Claims] 1. A method of rolling a steel strip by a quadruple rolling mill equipped with a backup roll having a taper piston type variable roll crown mechanism, wherein a backup roll having a body longer than a work roll body is used. A method for rolling a steel strip, which comprises rolling while controlling the shape of the steel strip.