JPS5937688B2 - Rolling method in hot rolling equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling method in a hot rolling facility, and particularly to a rolling method aimed at correcting the crown of a plate.

The shape of the rolled plate obtained by hot rolling is extremely important in carrying out the next step of cold rolling.

That is, Fig. 1) The plate thickness hc-he at the plate center and plate end shown in this figure.
is called a plate crown, but if this amount is not approximately constant, the next step of cold rolling will be, for example, if the plate crown exceeds the target by one point, it will become a material with medium elongation, and if it is less than the target, it will become an edge elongated material. This is because the product will be in a bad shape and the product value will be lost.

The occurrence of such a plate crown is caused by the non-uniform temperature of the rolled material during hot rolling, that is, the temperature difference between the tip of the rolled material and the end of the layer, and as a result of changes in the rolling load. However, as the number of rolling cycles increases, the roll expands due to heat conduction from the hot rolled material, causing the shape of the roll to change over time (referred to as thermal crown).

Conventionally, control at one stage during rolling of such a plate crown involves adjusting the temperature of the material before rolling.

In addition, only rough methods have been used for thermal crowns, such as heating the roll with a gas burner before rolling, providing a thermal crown in advance, and starting rolling.

However, through the efforts of Applicant Kanayama, a rolling mill that can significantly control the sheet crown has been put into practical use by moving the roll of the rolling mill by one angle relative to the sheet width of the rolled material. .

The present invention relates to a method of controlling sheet crown by effectively utilizing the functions of this new type of rolling mill.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

An example of a new type of rolling mill used in this invention is shown in Figure 2).
It has this structure and has an extremely wide range of plate crown correction capabilities.

This rolling mill is equipped with one to six rolls between the tenth window surface 2 and the window lower surface 19 of the rolling mill stand.

In this rolling mill 1, the method of controlling the plate crown of the rolled material 10 is as follows: upper and lower work rolls 8. I
L A bearing box that acts to directly bend the work roll in a roll group consisting of six rolls: upper and lower intermediate rolls 6.14 that support this, and upper and lower reinforcing rolls 4 and 17 that support the rolling load. 7 and 9) and a device for the roll bender 18 (detailed illustration is omitted, but normally the operating force is provided by one hydraulic cylinder), and the intermediate roll 6.
The plate crown is controlled by a roll moving device 12 (not shown in detail, but usually moved by a hydraulic cylinder or an electric motor via a screw).

We investigated the two types of strip crown control capabilities of this new rolling mill for the average strip width of normally rolled material of about 1400 mm, and found that the strip crown control effect with the roll bender mentioned above was about 150 μm, whereas the roll bender had a crown control effect of about 150 μm. It has been found that the plate crown control effect due to one movement is about 250μ.The plate crown control ability due to both of these can be roughly considered to be the sum of the two, and has a control ability of about 400μ.

On the other hand, the amount required for controlling the crown of the plate during rolling is about 300μ, and it has been found that the plate crowning capacity of the new rolling mill is sufficient.

Now, when performing hot rolling, plate crown 1 of the rolled material
Factors that influence this include the above-mentioned roll thermal crown (which changes by about 250μ), which changes significantly with the increase in the number of times a rolled material is processed over time, and the
This factor exists, namely, the temperature at the tip of the rolled material is high;
The results of actual rolling operations are affected by the change in rolling load (approximately 50μ) caused by a phenomenon in which the temperature decreases over time as the trailing end moves forward (approximately 50μ). It was clear from the analysis.

The present invention attempts to control plate crown changes caused by these factors by effectively utilizing the plate crown control function of the above-mentioned new type of rolling mill.

In other words, in the new rolling mill, it is possible to control the plate crown by moving the rolls and using one roll bender, but when moving the rolls during rolling, the rolling load is about 150Cl, so the rolls must be moved. Approximately 300 tons of force is required.

Since a large force is required to move the rolls during rolling, the equipment for carrying this out is also expensive.

From this point of view, the present invention focuses on the fact that the required amount of plate crown during rolling can be controlled only by a roll bender, and the amount of plate crown required for controlling the plate during rolling can be controlled by a roll bender that directly bends the rolls. ), and the rolls are moved during the rolling pass, that is, in an unloaded state until the next rolling material arrives, thereby making it possible to control the factors that greatly affect the sheet crown.

This aims to take advantage of the full range of plate crown control capabilities of the new rolling mill.

As described above, the present invention is a method of separately using the two sheet crown control functions of a new rolling mill, that is, during rolling, a roll bender is used to move one roll during unloaded periods between passes. Therefore, it is an object of the present invention to provide a method for controlling the plate crown during hot rolling, which is economical and makes effective use of each plate crown control ability.

In addition, the new rolling mill is constructed with six rolls as shown in Fig. 2, and in a further example, there are no upper and lower intermediate rolls as shown in Fig. 2, and a total of four rolls, including upper and lower work rolls and upper and lower reinforcing rolls. It is composed of a roll of books, and in this case the reinforcing roll is moved, but the effect is the same, and it goes without saying that this may also be used.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a plate crown, and FIG. 2 is a diagram showing a new type of rolling mill used in this invention. Explanation of symbols, 4, 17...Reinforcement roll, 6゜1
4... Intermediate roll, 8, 11... Work roll, 12... Roll moving device, 18...
...Roll bender.

Claims (1)

[Claims] 1. In a hot rolling facility equipped with a rolling mill that moves the roll axis relative to the width of the rolled material, the rolling material is bitten by the rolling mill to correct the plate crown of the rolled material. During the rolling process, the roll bender is controlled, and during the interpass time until the rolled material is extracted from the rolling mill and the next rolling starts, the roll bender of the rolling mill is adjusted to correspond to the rolling characteristics of the next rolled material. A rolling method in one hot rolling facility, characterized in that the plate crown is corrected by adjusting the amount of roll axis movement.