JPS5828002B2 - Plate crown control rolling mill row - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling mill for plastic materials, such as metallic materials, and more particularly to a rolling mill capable of effectively controlling the crown and shape of sheet material.

In rolling VC of plate material, it is necessary to obtain a rolled product with a good shape and a small plate crown from the viewpoint of product quality and yield.

To meet this requirement, conventional 4-high rolling mills, etc.
A so-called roll bending method has been put into practical use, in which a roll is bent by a bending device to roll a plate material.

However, with this method, it is not possible to apply a very strong bending force in current rolling mills due to the strength of the roll neck, the life of the bearings, etc., and the work roll and reinforcing roll cover almost the entire length of the roll. Since the bending effect cannot be achieved as much as the bending effect due to contact, there is a limit to the ability to control the plate crown and plate shape, and there is a problem in that sufficient effects cannot be achieved.

The present inventors have developed a rolling mill configured as shown in FIG. 1 in order to solve the problems of the conventional method described above.

This rolling mill uses reinforcing rolls 3 and 3' that support work rolls 2 and 2' for rolling a plate material 1 having a width B, and a work roll that is shorter than the effective length of the work rolls 2 and 2'. The reinforcing roll body has a length that is in contact with at least one circuit, that is, an effective body length L', and a step is present on the outer side of the effective body length L', and a convex portion is formed on the effective length. It is given a crown of the shape.

Buttons 4 and 4' are work roll bending devices with 2° and 20 rolls.

With this configuration, if an appropriate effective body length L' is set for the reinforcing rolls 3, 3', the work rolls 2, 2' can be bent effectively and over a wide range since the reinforcing rolls 3, 3' have step portions at both ends. It is possible to obtain effective plate crown, plate shape change, and control ability for various plate width levels.

On the other hand, in conventional plate rolling, it is considered that the crown cannot be changed significantly because changing the crown would deteriorate the shape.

Regarding this point, the present inventors have found that, especially in the rolling pass stage before the intermediate stage where the plate thickness is large during hot rolling, even if the plate crown is changed significantly, the metal flow in the width direction In addition, when rolling passes consisting of multiple passes, excluding the final pass,
As a result of research, we have found that even if the plate crown is changed over a wide range during the middle pass I/L, if the plate shape is corrected and controlled in the final pass, the plate shape before the final pass will be erased.
I came to this knowledge.

In other words, we succeeded in constructing a pass schedule that allows both crown correction and obtaining a good shape.

The bending device 4 of the work roll 21 has a shorter effective body length L' than the work roll shown in FIG. If rolling mills having 4' are arranged in the final stage and one or more stands other than the final stage to form a rolling mill row, the crown of the plate can be changed to the desired crown in the stands other than the final stage. The roll bending device 4 is pressed so that the final stage is pressed to make the board shape good.
4' and correct its shape, the reinforcing roll effective body length L' and its effective body length are set so as to have a preferable rolling load width for the width B of the rolled material as shown in Fig. 1. Combined with the effect of the crown on the part,
You can get a good round shape.

However, in order to further improve the ability to control the plate crown and plate shape, it became necessary to create a new technical idea regarding the configuration of the rolling mill row.

The object of the present invention is to provide a practical rolling mill row that can solve the above-mentioned problems and improve the plate crown and plate shape control.

However, the feature is that the rolling mill row KL is constituted by a rolling mill having a reinforcing roll whose body length in contact with at least one generatrix of the work roll is shorter than that of the work roll. The main feature is that the length of the reinforcing roll is set to one or more types between rolling mills depending on the width size level of the material to be rolled.

The plate crown control rolling mill train according to the present invention will be explained in detail below based on its embodiments.

The effective trunk length L' of a reinforcing roll whose trunk length is shorter than the aforementioned work roll trunk length and whose trunk is crowned changes in accordance with the size of σ', as shown in Fig. 3. It is determined by the amount of crown change (vertical axis) and regulations such as medium elongation limit and spalling limit.

Among them, σ is ((L'-plate width)72)-c and is expressed on the horizontal axis.

Normally, the above-mentioned regulation is set based on a large width size that becomes effective most quickly when σ is changed in the negative direction with respect to the amount of change in σ.

Although the reinforcing roll effective body length set in this way is effective for all strip widths in terms of the greatest common divisor, when attempting to perform even more fine-grained crown control, it is necessary to It is necessary to set the effective length L' of the reinforcing roll according to the following.

To explain this point in more detail, FIG. 3 shows the magnitude of δ on the horizontal axis and the crown value that can be reached on the vertical axis.

The fact that δ is right in the negative region indicates that the effective body length L' of the reinforcing rolls 3, 3' shown in FIG. 1 is shorter than the rolled plate width B at that time.

In this figure, L'=914.1257, 1543°1829
．． For each level of 2286 (unit amount), for example, L
'= When set to 914mm, the rolled plate width is 1829mm, unless the medium elongation limit and sports ring limit are taken into account.
The material can reach a crown (vi, 10μ).

Here, mid-elongation refers to when the value of L' is extremely small relative to the sheet width, the rolling load is concentrated at the center of the sheet width, and the central portion of the sheet material is stretched too much in the width direction compared to the side edges. This refers to the shape in which the center width of the later plate material is wavy in the longitudinal direction.

Therefore, is the medium elongation limit due to the fact that this medium wave shape does not occur? This is the limit.

Also, spalling is extremely low compared to the length of the work roll.
If is small, the reinforcing roll will receive a large line load on its short effective body, and this will occur on the outer periphery of the roll body.

This spalling limit is a limit to prevent this spalling from occurring.

From these considerations, it is necessary to set a value for L' that does not exceed each limit.

In Figure 4, L = 1257 mm, and the board width at each level is 18
28.8 meters (6 feet), 1524 meters (5 feet)
, 1219 feet (4 feet) and 914.4 feet (3 feet) of material compared to that in a conventional 4-high rolling mill and how the roll bending effect changes. This shows that.

Here, the roll bending effect amount refers to the amount of plate crown reduction that is further added when roll bending is applied.

In this case, if a plate of 1828.8 mm (ft) is rolled, a plate crown reduction of 80μ can be obtained, but when a plate with a width of 914,47 ItrIL (3 feet) is rolled, the plate crown reduction is 40μ.

When taking one straight line of L' for all strip widths, it must be one straight line of L' that takes into account the medium elongation limit and sports ring limit based on the maximum plate width processed by the rolling mill. .

In view of the above points, the present invention has been developed by installing several rolling mills with straightness of L' in a rolling mill row, and rolling mills with straightness of L corresponding to the strip width level at this time. Since rolling is performed using
It becomes possible to control the plate crown with higher precision than by determining the value and rolling.

In this case, a rolling mill having an L' straightness that does not match the current strip width level may be given an empty pass or a very light rolling reduction may be applied.

In this way, the rolled material whose plate crown is controlled by a desired rolling mill according to the plate width is applied to the entire plate width size in order to control the shape to the desired shape at the final stand. Rolling is done in a rolling mill with a straight shaft and a roll bending device, resulting in a smooth product.

FIG. 2 shows an embodiment of the present invention.

Regarding the rolling mill row shown in this example, the #7 stand, which is the final stand, is equipped with reinforcing rolls and a roll bending device having an effective loin body length L' that is the greatest common divisor and corresponds to all sheet width sizes. Place the rolling mill, #2
The stand has a board width of 1524mm (5 feet) and #4
The stand has a board width of 2133.6 mm (7 feet),
The #5 stand is equipped with a rolling mill having a reinforcing roll effective body length L' corresponding to each 914.4 feet (3 feet) sheet width.

In such a rolling mill row, for example, 2133.6 m
When rolling a plate material with a width of m (7 feet), 914
．． #5 stand for 4im (3 feet) has an empty pass or 68<light pressure, and crown control is mainly performed with #4 stand.

Thereafter, in the same way, depending on each board width level, the stand that falls down is set to an empty pass or a very light rolling pass, and crown control is performed mainly with the stand corresponding to that board width level.

Since the plate crown control rolling mill train according to the present invention is constructed and operated as described above, it is possible to control the plate crown and shape extremely effectively and with high precision, and it is very practical and effective in rolling operations. It brings about industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing rolling mills constituting a rolling mill row according to the present invention, FIG. 2 is a diagram showing an embodiment of the rolling mill row according to the present invention, and FIG. A chart showing the achieved crown amount determined from the direct level of the effective body length L' of the reinforcing roll of the machine and the rolled plate width. Figure 4 shows the amount of crown reduction for each pupil of L' and the rolled plate width level and the roll. FIG. 3 is a diagram showing the amount of bending effect.

Claims (1)

[Scope of Claims] 1. The length of the body of the work roll in contact with at least one line is made shorter than that of the work roll, and the rolling line has a reinforcing roll with a crown, corresponding to the width size standard of the material to be rolled. A plate crown control rolling mill row comprising one or more plate crown control rolling mills having a body length of The body part of the reinforcing roll with a crown added to the body part,
A plate crown control rolling mill row characterized in that it is configured as one or more types corresponding to the width size level of the material to be rolled.