JPS61212410A - Skin pass mill - Google Patents

Abstract

PURPOSE:To manufacture inexpensively a metallic strip ranging from thin to thick ones in a skin pass mill by attaching a tension leveler to the housing of mill. CONSTITUTION:A tension leveler 2 is directly attached to the housing of an outlet side of mill 1, to utilize the housing as a part of leveler housing. Further, an extension leveler 2a is disposed in the housing of mill 1, and a straightening leveler 3 is attached to the outside of housing. Furthermore, both of a rolling roll unit and a leveler unit are assembled in a cassette form and are mounted freely detachably on the inside of a window of mill 1, to deal with a thin stock by the rolling roll unit and a thick stock by the leveler unit. Tension providing devices, capable of performing tension leveling for either system, are disposed at the front and back of the mill 1. By these mechanisms, a compact leveler can be provided to a mill at low cost.

Description

Detailed Description of the Invention (a) Industrial application field The present invention relates to a skin bath mill that incorporates a tension leveler into an existing rolling mill. (b) Prior art Recent hot rolled steel strips Flatness requirements are becoming increasingly strict, and conventional equipment (double or quadruple skin bath mills) is no longer able to meet these demands. To ensure flatness, high tension priddles are used before and after the rolling mill.
The first idea is to provide a roll to improve the shape level.

However, from the perspective of stably ensuring high flatness, it is considerably inferior to so-called tension levelers. A tension leveler is a machine that corrects the shape of a steel strip by applying plastic elongation of 0.2 to 0.5% by bending and tensioning, and is widely used as the most efficient equipment. However, as the thickness of the plate increases, the necessary tension becomes 50 to 70 tons, which has the drawback that the tension applying device becomes enormous in terms of equipment size and cost. Therefore, as equipment capable of rolling thin to thick materials, a method has been proposed in which thick materials are primarily handled by a rolling mill, and thin materials are primarily handled by a tension leveler.

The combination of rolling mill and tension leveler is shown in Figure 4 (
Representative examples are shown in A) and (B). (A) In the figure,
It has a configuration in which a four-layer rolling mill 1 and a tension leveler 2 are separated from a priddle roll 5.

In the figure (B), a rolling mill 1 and a tension leveler 2 are arranged in series, and priddle rolls 5 are provided on their entry and exit sides.

(A) In the configuration shown in the figure, the elongation rates of the rolling mill 1 and the tension leveler 2 can be controlled separately. (B) In the configuration shown in the figure, even if the elongation rates of both the rolling mill 1 and the tension leveler 2 can be controlled simultaneously, the elongation rate of either one alone cannot be controlled. However, since the intermediate priddle roll 5 is not provided, the cost becomes cheaper compared to the structure K shown in FIG.

Thus, traditionally, rolling mills and tension levelers have been designed to be housed in separate housings. However, since the tension leveler pressure is significantly lower than that of a rolling mill, there is no need to go to the trouble of making a separate housing for the leveler.

(/C) Problems to be Solved by the Invention The problems to be solved by the present invention are the skin bath mill, which can effectively utilize existing rolling mills to produce thin to thick metal strips at low cost; It's about getting.

B) Means for solving the problem The skin bath mill of the present invention solves the above problem by installing a tension leveler in the housing no. 15 on the exit side of the rolling mill.

The skin bath mill of the present invention also solves the above-mentioned problems by having straightening levelers extending into the housing on the exit side of the rolling mill and also mounted outside the housing.

The skin bath mill of the present invention also solves the above problems by detachably mounting a rolling/straightening unit within the window of the rolling mill.

The above-mentioned problems have also been solved by using any one of the above-mentioned skin bath mills to flatten the hot-rolled steel strip as it is or after pickling.

(e) Examples 1 and 2 wm thickness to 6.51 mm thickness (mainly 1.6 to 4 mm thickness)
Comparing the advantages and disadvantages of rolling mills and tension levelers for hot-rolled steel sheets with a thickness of 5.
It will look like Table 1. As shown in Table 1, the most ideal equipment is a combination of a four-layer mill and a tension leveler.

Table 1: Very good ◎ Good ○ Effective
Δ No effect at all Plate thickness 1.6 to 4 with X rolling mill
．． To roll a hot-rolled steel strip with a width of 1250 m and flatten it at a reduction rate of 1%, a four-layer mill with work rolls of 600 m in diameter requires 250 to 300 to
In the case of high tensile steel, a rolling load of 900 to 1300 tons is applied to n, 80. On the other hand, in order to obtain the plastic elongation of 0.5% necessary for flattening with a tension leveler, 5PH is required.
8 to 10 tons in C.

An average tension of 22 to 30 tons is required for high tensile strength steel. The force applied to the leveler housing at the end is about 50 to 90 tons at most, depending on the number of rolls. Therefore, the housing of the rolling mill is 100ton
It is necessary to have the strength to withstand the above load, but on the other hand, the leveler housing only needs to withstand a load of less than 70 mm. However, conventionally, Figures 4 (A) and (B)
As shown in Figure 2, the rolling mill and leveler were constructed in separate housings to form a line. As a result, the height of the a-strike became higher and the space became larger.

As shown in FIG. 1, a conventional tension leveler 2 is mounted directly to the housing of a conventional rolling mill 1. This allows it to be used as a part of the leveler housing, which is a rolling mill housing, and also has the advantage of requiring less space.

In FIG. 2, an elongation leveler 2α for imparting plastic elongation to the steel strip is installed in the housing of a conventional rolling mill 1, and a straightening leveler 3 for adjusting the warpage of the steel strip is attached to the outer surface of the housing. To replace the rolls of the extension leveler 2α, after removing the straightening leveler 3, pull the extension leveler 2α out of the housing on the rail IT attached to the inner surface of the housing.・Leveler 2 (
Although we do not plan to use it in combination with (Fig. 1), we have prepared two units, a rolling roll unit and a leveler unit, and these units 4 can be freely attached and detached in a cassette type inside the window of the rolling mill 1 (at the installation position of the rolling rolls). Attach to. Thick materials are handled by a rolling roll unit, and thin materials are handled by a leveler unit.

In either method, a tensioning device capable of tension and leveling is installed before and after the rolling mill. In general, it may be possible to apply high tension with a direct reel using a priddle roll.Specific Example: A four-layer rolling mill with a work roll of diameter 600W5 and a backup roll of diameter 1200m. 30 tons front and rear
As shown in Figure 1, on the exit side of the rolling mill, a group of 4 pridle rolls with a tensile strength capacity of 4 and a supply reel and a take-up reel are installed outside the prydle rolls.
Two 0a+ extension rolls, diameter 90m, and 300m
Various tests were conducted using a part of the 0-leveler housing equipped with a leveler unit consisting of two straightening rolls compactly arranged with sIIWX, which also serves as a rolling mill housing.〇Thickness: 1.6 wa General lumber with a width of 1250 wm was mill-opened and tensioned and leveled. As a result, the base material steepness of 3% could be corrected to a steepness of 0.3% or less. However, with the 100K high tensile strength material, the tension was limited and it was not possible to achieve a sufficient straightening effect, so when we lowered the rolling mill, we were able to achieve a steepness of 0.3% or less by rolling + tensile/leveling. .

For a general thick material with a thickness of 6.35w x width L of 250rm, tension and leveling alone will cause a slight change (o, t~0.2
Although the plastic elongation of h) was obtained, even the plastic elongation was not obtained at the width of 1550 stitches, but the leveler was opened and rolling mill rolling was performed under high tension. As a result, the steepness is 0.
A thickness of 5 inches or less was obtained, and when the exit leveler was reduced slightly and used in conjunction with a rolling mill, the flatness was further improved.

Next, high tensile strength materials were tested. With a tension leveler, we were able to obtain some plastic elongation with a 5m thick material made of high tensile strength 60 up to a width of 750 f1, but for wider widths, no straightening effect could be achieved at all, so we opened the leveler. Then, when the rolling mill was rolled down and rolled at maximum tension, the steepness could be reduced to 0.5 inch or less. For thick products, the shape of the base material is generally not that bad, so a fairly high level of flatness can be ensured with just the mill. As shown above, by manufacturing a skin bath mill that is compact and leveler attached to the rolling mill housing. ,
An example will be described in which a leveler is incorporated into a zero-order cold-rolling tempering mill, which can sufficiently meet the high flatness requirements and at the same time significantly reduce equipment costs. We will discuss in detail the town in which a leveler is installed in the front and rear priddle rolls and temper mill housing as shown in Figure 2. A leveler with electric reduction consisting of two work rolls with a diameter of 60 W and four backup rolls with a diameter of 150 m was installed inside the rolling mill housing, and a rail was provided inside the housing to make it possible to pull out. Furthermore, the outer surface of the housing has a diameter of 8 mm.
0smXa (2 are backup rolls) and diameter 2
A straightening roll made of 00- was attached. With this device,
A tinplate original plate with a thickness of O, 191) and a width of 850 was subjected to temper rolling. Conventionally, since the material is thin, it has not been possible to achieve sufficient flatness correction, and troubles have often occurred due to poor flatness.

The flatness has been greatly improved by introducing the book scraper. Special K
.

The shape of the exit side has been improved, so the line speed can be greatly increased.
Productivity has also improved. Furthermore, for products that do not require high flatness, it is advisable to use a leveler oven to increase the life of the leveler roll. By applying it at a cost, it is now possible to ensure good flatness from thick to thin materials.

[Brief explanation of the drawing]

FIG. 1 is a side view of a skin bath mill of the present invention in which a conventional tension leveler is incorporated into a conventional rolling mill. FIG. 2 is a side view of the skin bath mill of the present invention, which incorporates a conventional extension leveler into a conventional rolling mill. Figure 3 is a side view of the skin bath mill of the present invention in which a rolling/straightening unit is removably incorporated into a conventional rolling mill (however, in the case of a leveler unit) Figure 4 is a schematic illustration of conventional rolling equipment . 1: Rolling mill 2: Tension 0 leveler 2α; Extension leveler 3: Straightening leveler 4: Rolling/straightening unit Fig. 2

Claims (4)

[Claims] (1) Tension is applied to a part of the housing on the exit side of the rolling mill.
A skin bath mill featuring a leveler. (2) A skin bath mill characterized in that an extension leveler is installed inside the housing on the exit side of the rolling mill, and a straightening leveler is installed outside the housing. (3) A skin bath mill characterized in that a rolling/straightening unit is detachably attached within the window of the rolling mill. (4) A hot rolled steel strip is processed with a black skin or pickled using a skin bath mill according to any one of claims (1) to (3). A method for flattening a steel strip, which is characterized by flattening the steel strip afterwards.