JPH04262803A - Quenched and tempered rolling equipment - Google Patents

Abstract

PURPOSE:To control the size of cross buckle (bellows) in the quenched and tempered rolling of a steel strip. CONSTITUTION:Because a variable crown roll 5 of which the roll crown is adjustable is provided as an auxiliary roll in the just rear of work rolls 3, an outward force (widening force) in the width direction of the steel strip 1 is added and an inward force (narrowing force) in the width direction at roll bite can be mutually canceled by making the roll crown concave in the case of large cross buckle.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a crossback (bellows)
This invention relates to temper rolling equipment for steel strips that can control the size of steel strips.

0002

2. Description of the Related Art Generally, cold-rolled steel sheets are subjected to temper rolling after annealing to prevent stretcher strain during processing, but at this time wavy undulations called cross buckles or bellows are produced. This cross buckle is sometimes preferred because it increases the strength against bending of the steel plate, but it causes problems in threading and abrasion, and it also does not look good, so it should be made as small as possible.

[0003] The following mechanism is known for the occurrence of cross buckles. In other words, the steel strip tries to widen during the roll bite of the temper rolling mill, but
The roll exerts a force in the direction of suppressing the width expansion. As a result, when the force that suppresses the width expansion exceeds a certain amount, wavy buckling occurs in the width direction. Therefore, in general, in order to make the cross buckle smaller, the plastic flow itself is reduced by reducing the rolling force, or the rolling mill exit tension is increased so that the plastic flow becomes dominant in the rolling direction. There are known ways to do this.

0004

[Problems to be Solved by the Invention] However, with the above-mentioned method of reducing the rolling force, the transfer rate of the roughness of the work roll to the steel strip becomes small, resulting in the problem that the surface roughness of the product cannot be controlled. There was a problem that the elongation became large. Further, in the method of increasing the tension, the curvature of the steel strip in the auxiliary roll on the exit side of the rolling mill changes, so there is a problem that the warpage changes.

[0005] As disclosed in Japanese Utility Model Application Publication No. 62-29801, a device is known that uses an auxiliary roll with a variable crown on the entrance side of the rolling mill. The purpose is to prevent wrinkles that sometimes occur.
Further, since the force applied to the steel strip only affects the stress in the width direction at the entrance side of the rolling mill, it has no effect on cross buckling, which is a phenomenon that occurs after roll bite in the rolling mill.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a steel strip skin pass rolling facility that can control the size of the cross buckle.

[0007]

[Means for Solving the Problems] The present invention provides a steel strip skin pass rolling equipment having a work roll of a final stand of a skin pass rolling mill and at least one auxiliary roll between the work rolls of the final stand. The temper rolling equipment is characterized in that the auxiliary roll closest to the stand is a roll whose roll crown can be adjusted.

[0008]

[Operation] When rolls with various roll crowns were brought into contact with a steel strip under constant tension, it was found that the force exerted on the steel strip at the position of the roll was as shown in Figure 2. That is, when the roll crown is convex, the external force acts toward the center of the steel strip, and when the roll crown is concave, the external force acts in a direction that widens the width of the steel strip. This is the same principle as the belt wheel.

[0009] In order to solve the above problems, the present invention has the following features:
Utilizing this experimental result, a variable crown roll was used as the auxiliary roll closest to the work roll. According to the present invention, as shown in FIG. 1, since the variable crown roll 5 whose roll crown can be adjusted is installed on the auxiliary roll immediately after the work roll 3, the roll crown can be adjusted when the cross buckle is large. By making it concave,
An outward force (force to widen the width) is applied in the width direction of the steel strip 1, and the inward force in the width direction (force to shorten the width) in the roll bite can be offset.

Therefore, the relationship between the size of the roll crown of the auxiliary roll and the cross buckle is as shown in FIG. 3, and by controlling the roll crown, it is possible to create any desired cross buckle. Note that the size of the cross buckle here is as shown in Figure 4.
It means the height of the ridges when the steel plate 1 is left still and the stylus 6 is moved in the width direction, or (height of the ridges) ÷ (pitch between the ridges).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view schematically showing a final stand 2 of a temper rolling mill according to the present invention and an auxiliary roll 5 closest to the final stand 2. In the present invention, a variable crown roll whose roll crown can be adjusted is used as the auxiliary roll 5. 1 is a steel strip, 3 is a work roll, and 4 is a backup roll.

In order to adjust the roll crown of the variable crown roll, the size of the cross buckle can be adjusted based on the results of measuring the size of the cross buckle using a cut sample, or the size of the cross buckle can be adjusted using an online cross buckle measuring machine installed after the auxiliary roll. A method may be used as appropriate to measure the roll crown and control the roll crown to an optimum value based on the measured value.

FIG. 5 is a diagram comparing the size of the cross buckle in the embodiment of the present invention and the conventional example. In the example of the present invention, since the roll crown of the auxiliary roll was controlled by the size of the cross buckle, good results were obtained in which the average value was smaller and the variation was smaller than in the conventional example.

[0014]

Effects of the Invention As explained above, the present invention uses a variable crown roll as an auxiliary roll immediately after the work roll, so that the rolling force and tension can be maintained without changing the plate surface roughness or warpage. Now you can reliably control the cross buckle without changing it.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a final stand of a temper rolling mill and an auxiliary roll closest to the final stand in the present invention.

FIG. 2 is a diagram showing the relationship between the roll crown and the force acting toward the center of the steel strip.

FIG. 3 is a diagram showing the relationship between the roll crown and the size of the cross buckle.

FIG. 4 is a diagram showing a method for measuring the size of a cross buckle.

FIG. 5 is a diagram showing an example of the present invention in comparison with a conventional example.

[Explanation of symbols]

1 Steel strip 2 Final stand of temper rolling mill 3 Work roll 4 Backup role 5 Auxiliary role 6 Stylus

Claims (1)

[Claims] 1. In a steel strip temper rolling facility having at least one auxiliary roll between a work roll of a final stand of a temper rolling mill, the auxiliary roll closest to the final stand is , a temper rolling facility characterized by using rolls with adjustable roll crowns.