JPH0824951B2 - Hot rolling method for aluminum slabs - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for aluminum slabs, and the aluminum slabs of 400 to 600 are used.
An object of the present invention is to provide a method capable of appropriately preventing defects on the surface of a slab upon heating to a predetermined temperature of ° C and hot rolling and obtaining a product having good surface quality.

[0002]

2. Description of the Related Art In order to obtain a rolled sheet material or the like from an aluminum slab obtained by a semi-continuous casting method or the like, a heating step prior to rolling is carried out in a heating furnace, and then hot rolling is performed. Although indispensable, in the heating process in such a case, dust in the furnace and metal oxides such as iron, nickel and chrome adhere to the surface of the slab. If these deposits are pressed into the aluminum plate during the hot rolling process and remain on the surface of the final product, a difference in the current density will occur when electrolytic etching is performed, resulting in overcurrent around the iron powder and uneven etching. Cause a defect.

Therefore, various studies have been made to remove the deposits on the surface of the slab before hot rolling, that is, a cleaning method in which high-pressure water is sprayed on the surface of the slab to wash it away, a wiping method with a rotating brush, and a heat-resistant cloth. There is a wiping method, etc.

[0004]

However, it is difficult to obtain a desirable result by any of the conventional techniques as described above. That is, in the case where the removal treatment is not performed, residual dust that reaches 0.03 g / m ² or more attached to the surface of the slab by the hot air in the heating furnace remains, so that surface defects are remarkable after rolling.

In the method of injecting high-pressure water onto the surface of the slab, adhering dust can be removed by 75% or more by injecting a large amount of water onto the surface of the slab. Since it is necessary to inject water, the surface temperature of the slab is considerably lowered, and the effect of high temperature heating at a certain degree is greatly diminished. In addition, the facility cost increases, and the cost is inevitably high in terms of the amount of water consumed.

In the wiping method using a rotating brush, the equipment is relatively inexpensive and small in size, but when synthetic fiber material is used as the brush bristle material, it is melted and deteriorated, and other brushes are prevented from self-contaminating and the above temperature conditions are satisfied. In the case of a hard material such as stainless steel that takes heat resistance into consideration, defects will be significantly generated on a soft slab surface at high temperature and the surface quality will be impaired.

The method of wiping with a heat-resistant cloth is generally a delicate operation by a worker, and it is extremely difficult to give a uniform removing effect to the entire slab surface having a large area at high temperature, and automation is not possible. It is difficult and is likely to impair the surface quality as with a rotating brush.

The present invention has been studied to solve the problems of the above-mentioned conventional techniques, and by adopting a rotary brush using a plant fiber material under a liquid supply condition, a preferable removal effect and a slab surface can be obtained. The present invention succeeds in obtaining a preferable rolled material by preventing scratches and rolling under the condition that the attached dust is removed in this way, and is as follows.

The aluminum slab heated to 400 to 600 ° C. is subjected to a slab surface wiping treatment under a condition in which a liquid containing a corrosion inhibitor is controlledly supplied to a rotary brush made of vegetable filaments, and then rolled by a roll. A hot rolling method of an aluminum slab, which is characterized by being performed.

[0010]

The aluminum slab heated to 400 to 600 ° C is wiped on the slab surface under the condition that the liquid containing the corrosion inhibitor is controlled and supplied to the rotating brush made of vegetable filaments. Remove the attached dust.

Further, in this case, since the amount of liquid supplied is controlled as described above, the heating temperature raising effect in the heating furnace is appropriately maintained without excessive cooling of the slab surface. In addition, the liquid supplied in this manner prevents alteration of the plant long fibers composing the brush and makes the plant proper soft, and avoids the occurrence of flaws on the slab surface due to such contact of the plant fibers. It is a plant fiber and, together with the cooling effect of the liquid supply to the slab surface as described above, it protects the brush constituent fibers from burning and other deformations and alterations and maintains an appropriate wiping action.

By performing rolling with a roll under the conditions where the dust is appropriately removed and the cooling of the slab surface is controlled as described above, an aluminum rolled sheet having a good surface quality can be obtained accurately, and good quality can be obtained. It is possible to obtain a good aluminum plate at a relatively low cost.

[0013]

EXAMPLE As described above, a concrete embodiment of the present invention will be described. As is well known, the temperature of the slab heated by circulating hot air in the heating furnace and discharged from the furnace is 400 to 600 ° C. , Such a slab 1 is shown in FIG.
The rolling rolls 7 are sent to a rolling facility having the upper and lower rolling rolls 7 arranged as shown in FIG. 2 and subjected to the wiping action by the rotating brush 3 when undergoing rolling, but in the present invention, in this case, the rotating brush 3 As the fiber material, plant long fibers 4 such as sisal fiber and palm fiber are used.

The specific structure of the rotating brush 3 is shown in FIG.
As shown in FIG. 3, a cylindrical body 5 is used as a brush shaft, and the vegetable filament 4 is planted in the cylindrical body 5 as shown in the figure, and at the same time, a liquid passage hole 6 is arranged in the cylindrical body 5. Such a cylinder 5
A liquid such as water containing oil and other corrosion inhibitors is fed into the inner hole of the above to be appropriately controlled through the liquid passage hole 6 and discharged to the vegetable fiber 4 constituting the brush and the surface of the material to be rolled. Roll while supplying.

As a concrete example, a cylinder body 5 having an inner hole having a diameter of 25 mm is provided with a fountain hole having a diameter of 2 mm, and FIG.
Alternatively, as shown in FIG. 2, a rotary brush having a diameter of 300 mm, in which long-fiber sisal fibers are arranged, is prepared, the rotary brush is rotated at 60 to 80 rpm, and water containing 2% rolling oil as a lubricant is used as a cylinder. Send into the body 5, 10 per minute
500 to 520 ° C. while discharging and supplying at a rate of 0 liter
The heated slab 10 was fed at a speed of 20 mpm and hot-rolled to a thickness of 300 mm while being wiped.

Further, as a comparative example, in comparison with the above-described one according to the present invention, high-pressure water jet for jetting high-pressure water at a rate of 400 liters per minute onto the surface of the slab 10 under the condition that the feed speed of the slab 10 is reduced to clean Table 1 below shows a summary of the results of the method and the method in which a heat-resistant cloth wiping method of manually wiping with a glass fiber cloth is carried out, followed by rolling, and the case where no cleaning operation is carried out at all. is there. The high water pressure injection method requires at least several times as long as the treatment time per unit area of the slab according to the method of the present invention, and the heat resistant cloth wiping method requires more time. Also requires a dedicated process for cleaning. The product according to the present invention was generally rolled while being wiped, and was extremely efficient.

[0017]

[Table 1]

That is, in each of the rolled sheets obtained as comparative examples, the occurrence of flaws was confirmed in each of them, and moreover, the slab was significantly cooled because a large amount of water was used for cleaning. The rolling torque was increased by about 5% as compared with the case of the present invention, which was not always preferable in terms of rolling surface properties.

In the case of the above-mentioned example of the present invention, the rotating brush diameter was changed within the range of 200 to 400 mm, the rotation speed was 40 to 200 rpm, and the slab feed speed was 8 to 40 mpm, particularly 10 to 30 mpm. The supply of water containing rolling oil is changed to 60 to 11 per minute.
As a result of changing the range of 0 liter, the residual dust weight on the slab surface was 0.003 to 0.0045 g.
/ M ² , which was a favorable rolling result.

[0020]

According to the present invention as described above, when an aluminum slab is heated to a predetermined temperature and hot-rolled, the occurrence of flaws on the surface of the slab is accurately prevented.
Further, it is possible to obtain an aluminum plate having a good surface quality without significantly lowering the temperature of the heating slab and further without giving any further disadvantage in the hot rolling process. It is a great invention.

[Brief description of drawings]

FIG. 1 is a perspective view of a lower roll side of rolling equipment for carrying out the method of the present invention.

FIG. 2 is an end view and a partially cutaway side view of a rotating brush.

FIG. 3 is a side view of a rotating brush portion in a wiping treatment state.

[Explanation of symbols]

 1 Slab 2 Transfer roll 3 Rotating brush 4 Vegetable long fiber 5 Cylindrical body 6 Liquid passage hole 7 Rolling roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Hotta 1-11-1 Koike, Inazawa City, Aichi Prefecture Nippon Light Metal Co., Ltd. Nagoya Plant (56) References JP-A-58-501418 (JP, A) Special Features Kai 57-42070 (JP, A)

Claims (1)

[Claims] 1. A slab surface is wiped off under a condition in which a liquid containing a corrosion inhibitor is controlledly supplied to an aluminum slab heated to 400 to 600 ° C. to a rotary brush made of plant long fibers, and then the slab surface is rolled. A method for hot rolling an aluminum slab, which comprises rolling.