JPS61249606A - Multi-stage cold rolling mill - Google Patents

Abstract

PURPOSE:To obtain a product having a beautiful surface without generating roll marks by displacing an intermediate roll having the body part length larger than the body part length of a work roll in the axial direction thereby crowing the shoulder parts of divided rolls in a backup roll. CONSTITUTION:The body part length of the intermediate roll 2 is larger than the body part length of the work roll 1. The displacement of a rolled product in the shape control thereof is therefore obviated even if the intermediate roll 2 is displaced in the axial direction thereof. The bearing boxes of the roll 2 are continuously or discretely displaced in the axial direction by a rack and pinion mechanism or fluid pressure mechanism on a sliding base. The backup roll 4 is constituted of the divided rolls 6 and the shoulder parts of the rolls 6 are crowned to an arc shape. The stress distribution is thus made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to improvements in multi-stage cold rolling mills, particularly medium diameter cluster rolling mills.

(Prior art) In recent years, rolling mills that can satisfy the demands for improved productivity and thinner cold-rolled products have been developed. Medium-diameter cluster rolling mills with significantly larger work roll diameters are attracting attention.

As such a rolling mill, JP-A-57-190708 discloses a rolling mill in which a work roll is supported by a pair of intermediate rolls, and further, these intermediate rolls are divided into a plurality of rolls (divided pieces) in the axial direction. In addition to being supported by multiple split backup rolls, both ends of the work roll and both ends of the intermediate roll are each supported by bearing boxes via bearings, and the bearing boxes of these work rolls and the intermediate roll are each independently supported. A medium diameter cluster mill is disclosed that includes means for loading roll pending wheels.

This rolling mill has the structure shown in FIGS. 4(a) and 4(b), and is suitable for cold rolling under high pressure such as steel strip, and is particularly suitable for cold rolling products having an excellent shape (flatness). It has the ability to control the shape.

FIG. 4(a) is a front view, and FIG. 4(b) is a side view. In FIG. 4, 1 is a work roll, 2 is an intermediate roll, and 3.4 is a backup roll. The backup rolls 3 and 4 are composed of four to five divided rolls 6, as shown in FIG. 4(b). 5 is a material to be rolled, for example a stainless steel strip.

However, when a steel strip or the like is cold rolled under high pressure using the above-mentioned medium-diameter cluster rolling mill, extremely high pressure is generated at both ends of the split roll 6 in the backup roll, as shown in FIG. If rolled for a long time in this state, roll marks will be generated on the intermediate roll that is in contact with the split roll. That is.

In the split roll 6, locations where stress is concentrated, as shown in FIG. 2, are locations where roll marks occur. This roll mark is transferred to the work roll and finally to the surface of the rolled product. When roll marks are transferred to a rolled product, uneven gloss occurs on the surface of the rolled product in the width direction, which poses a problem in the production of high-quality cold rolled products that require a beautiful surface.

Conventionally, as a means to solve such problems, the work roll and the intermediate roll have been frequently replaced, the work roll, the intermediate roll, and the backup roll have been made to have lower surface hardness in that order, or the intermediate roll has been rotated in its axial direction. Measures have been considered to displace it continuously or discretely.

However, these conventional means still have problems to be solved. In other words, replacing work rolls and intermediate rolls frequently reduces the operating rate of the rolling mill, resulting in a decrease in productivity. It also requires a large inventory of rolls, which causes problems in terms of productivity and costs. There's a problem.

Further, decreasing the roll surface hardness in the order of work roll, intermediate roll, and backup roll is not very effective in suppressing transfer of roll marks to rolled products.

Furthermore, displacing the intermediate roll in its axial direction
Although it is effective in suppressing the transfer of roll marks to rolled products, there are problems such as reduced intermediate roll life due to stress concentration at the ends of the divided rolls of the backup roll, and the need to control the shape of rolled products. There is a problem in terms of ability.

(Problems to be Solved by the Invention) The technical object of the present invention is to provide a rolling mill that can solve the above-mentioned problems in the prior art.

(Means for Solving the Problems) The gist of the present invention is to provide a work roll, a plurality of intermediate rolls that support the work roll, and a plurality of axially divided A multi-stage cluster rolling mill in which a group of rolls consisting of backup rolls are arranged symmetrically with respect to the material to be rolled, and an intermediate roll whose body length is larger than that of the work rolls is continuously or discretely rolled in the axial direction. The present invention provides a multi-stage cold rolling mill comprising: a means for displacing the plurality of divided backup rolls, and a backup roll having an arc-shaped crown R on each shoulder of each divided roll (split piece) in the plurality of divided backup rolls.

The present invention will be explained in detail below.

In a medium-diameter cluster rolling mill such as that disclosed in JP-A-57-190708, the cause of roll marks on rolled products is due to the occurrence of roll marks on the rolled products at both ends (shoulders) of the split rolls (divided pieces) in the split backup roll. In view of the high stress concentrations and the resulting transfer of roll marks to the cold rolled product, the inventors propose to eliminate stress concentrations in the split rolls of the backup roll;
We devised a technical method centered on blocking the transfer path of roll marks onto rolled products.

As a result, the inventors configured a rolling mill so that the shoulders of the divided rolls in the backup roll are crowned (rounded) and the intermediate roll in the roll group is displaced continuously or discretely in the axial direction. I did it like that.

When adding a crown (roundness) to the shoulders of the split rolls in the backup roll, it may be possible to taper the split rolls, but the inventors have determined through experiments that an arc is more effective than a taper. confirmed.

By rounding the split roll shoulders of the backup roll, sharp stress concentrations as shown in FIG. 2 can be removed, and stress distribution can be made uniform as shown in FIG. 3.

Although there is an optimum value for the amount of circular arc crown applied to the shoulder portions of the split rolls in the backup roll depending on the rolling conditions, in general, 1,000 to too, ooo mR is appropriate.

On the other hand, when rolling steel strip etc. using a medium-diameter cluster rolling mill, scum adheres to the ends of the split rolls in the backup roll due to contamination of the rolling lubricant and iron powder on the surface of the strip. The inventors have found that this is a factor in the occurrence of roll marks on the surface of rolled products.

Therefore, it is more preferable to provide means for removing scum from the end portions of the divided rolls of the backup roll, so that roll marks on the cold rolled product can be more completely erased.

Although a wiper may be provided as a means for removing scum at the ends of the split rolls, the scum can be reliably removed by applying rolling lubricant spray to both ends of the split rolls.

The present invention will be explained in more detail below based on the embodiment shown in FIG.

In FIG. 1, 1 is a work roll, and 2 is an intermediate roll, the body length of which is larger than that of the work roll I. By doing so, even if the intermediate roll 2 is displaced in its axial direction, the shape control of the rolled product can be prevented from changing.

Further, the intermediate roll 2 has a bearing box (not shown) on a sliding table, and the rack and pinion machine configuration is axially displaced continuously or discretely by a fluid pressure mechanism.

4 is a backup role, and in this example,
It is composed of five divided rolls 6. Split roll 6
For example, an arcuate crown with a diameter of 5.00 hmR is attached to the shoulder portion. 5 is a rolled product, for example stainless steel strip.

Reference numeral 7 denotes a lubricating oil supply nozzle, which applies high-pressure lubricating oil spray to the contact portion between both ends of the split roll 6 and the intermediate roll 2 in the backup roll.

Therefore, in the medium-diameter cluster rolling mill configured in this way,
For example, when rolling a stainless steel strip, while displacing the intermediate roll 2 in its axial direction, the split roll 6
Rolling is performed while applying lubricant spray to the contact area between the intermediate roll 2 and the intermediate roll 2.

(Effects of the Invention) Since the present invention is configured and operated as described above, a medium-diameter cluster rolling mill with high productivity and capable of high reduction rolling can be used without causing roll marks. , it is possible to obtain cold-rolled products with beautiful surfaces.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the upper half of the rolling mill structure according to the present invention, and FIG. 2 is a diagram showing the stress distribution in the axial direction of the split rolls in the backup roll. Fig. 3 is a diagram showing the stress distribution in the axial direction of the split rolls with rounded shoulders, and Figs. 4 (a) and (b) are front and side views showing a conventional medium-diameter cluster rolling mill. It is. ■... Work roll, 2... Intermediate roll, 3.4.
... Backup roll, 5... Rolled material, 6...
Split roll, 7... Lubricating oil supply nozzle.

Claims (1)

[Claims] A multistage cluster in which a roll group consisting of a work roll, a plurality of intermediate rolls that support the work roll, and a plurality of axially divided backup rolls that support the intermediate roll are arranged symmetrically with respect to the material to be rolled. A rolling mill, comprising means for continuously or discretely displacing an intermediate roll whose body length is larger than that of the work roll in the axial direction, and split rolls (divided pieces) in the plurality of split backup rolls. and backup rolls each having an arcuate crown R on each shoulder.