JPH0957304A - Manufacture of aluminum plate or aluminum alloy plate having small optical anisotropy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably manufacturing an aluminum plate or an aluminum alloy plate having small anisotropy (optical anisotropy) in reflection property of light in the rolling direction and in width direction perpendicular to the rolling direction on the surface of a plate. SOLUTION: After hot-rolling an aluminum ingot or an aluminum alloy ingot, further, cold rolling is executed and the aluminum plate or the aluminum alloy plate having the target thickness is manufactured. At this time, the rolling operation of the final pass in the cold rolling is executed, using rolling rolls the diameter of which is >=200mmϕ, and whose mean roughness Ra in the axial direction is <=0.35μm and rolling oil whose viscosity is >=2cs and, at the draft (r) of <=35%, so that the mean roughness Ra (μm) and the draft (r)(%) satisfy the relationship of the next inequality: r<=-300×Ra+125.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aluminum plate or an aluminum alloy plate having little optical anisotropy,
In particular, the present invention relates to a method for producing an aluminum plate or an aluminum alloy plate in which the anisotropy of light reflection characteristics in the rolling direction on the plate surface and the width direction perpendicular to the rolling direction is reduced.

[0002]

BACKGROUND ART Conventionally, an aluminum plate or an aluminum alloy plate having various thicknesses is hot-rolled by using an aluminum ingot or an aluminum alloy ingot that gives them, and then cooled by intermediate annealing. Manufactured by hot rolling. Then, the plate material thus obtained is further subjected to various kinds of processing and treatment depending on the respective use, and is made into an intended aluminum product.

By the way, the rolling roll used in the above-mentioned rolling operation usually has a circumferential streak attached at the time of the surface grinding. It is transferred in the rolling direction. Further, due to the transfer streaks, the difference in roughness between the rolling direction and the width direction (direction perpendicular to the rolling direction) of the plate becomes large, and therefore, the diffuse reflection of the rolled plate in the plate width direction is 100. %, While it becomes very small in the rolling direction, and there is a problem that the directionality of the reflection characteristics of the plate, that is, the optical anisotropy becomes large. ing.

If the anisotropy of the light reflection characteristics in the rolling direction and the width direction of the rolled plate material, in other words, the optical anisotropy becomes large, various problems occur in the process of processing such rolled plate material. Will be caused. For example, for a rolled sheet material, using an optical inspection device, when performing an inspection with light reflection characteristics, depending on the direction of light irradiation, if the reflection characteristics will change significantly,
The device is liable to malfunction and the normal inspection can no longer be performed. It has been recognized that such a malfunction of the apparatus is caused, for example, when the difference in diffuse reflectance between the rolling direction and the width direction exceeds 180.

[0005]

The present invention has been made in view of such circumstances, and its object is to determine the light reflection characteristics of the rolling direction on the plate surface and the width direction perpendicular to the rolling direction. An object of the present invention is to provide a method capable of stably producing an aluminum plate or an aluminum alloy plate having little anisotropy (optical anisotropy).

[0006]

In order to solve such a problem, the present invention performs hot rolling of an aluminum ingot or an aluminum alloy ingot, and then cold rolling to obtain aluminum having a target thickness. When manufacturing a plate or an aluminum alloy plate, the final pass rolling operation in the cold rolling is performed by using a rolling roll having a roll diameter of 200 mmφ or more and an average roughness in the roll axial direction: Ra of 0.35 μm or less, and a viscosity of Using rolling oil of 2 centistokes or more, when the rolling reduction is 35% or less, the average roughness: Ra (μm) and the rolling reduction: r (%) are as follows:
A method for producing an aluminum plate or an aluminum alloy plate having a small optical anisotropy, which is characterized in that the relationship of ≦ −300 × Ra + 125 is satisfied,
This is the summary.

In summary, in the process of manufacturing an aluminum plate or an aluminum alloy plate, the surface texture of the obtained plate material is greatly affected by cold rolling, particularly by final pass rolling. It became clear that, even in such a final pass rolling process, the grinding surface of the rolling roll surface was transferred to the plate, and the stronger the grinding streak, the more strongly it was transferred to the plate surface, While the surface roughness in the width direction increases,
The rolling direction roughness of the plate is not so affected by the strength of the roll grinding line. Therefore, in the case of a roll having a strong grinding line, the difference in roughness between the rolling direction and the width direction of the plate becomes large, and the directionality of the reflection characteristic of the plate, that is, the optical anisotropy becomes large. Further, the degree of transfer of the grinding streak is strongly influenced by the reduction rate, and the higher the reduction rate, the stronger the transfer rate.
Optical anisotropy becomes large.

From these facts, in order to manufacture a plate having a small optical anisotropy, it is necessary to weaken the roll grinding line and to reduce the rolling reduction in order to weaken the transfer. , Although it is possible to reduce the optical anisotropy by simply flattening the plate surface, there is a problem that the amount of diffuse reflected light becomes small and therefore inspection using diffuse reflection cannot be performed. However, since a certain degree of plate surface roughness is required to prevent slippage, etc., such a measure was not sufficient.

On the other hand, in a normal rolling operation, small pits called oil pits are formed on the plate surface. The oil pits weaken the transfer of the grinding line of the roll and alleviate the optical anisotropy. Therefore, in the present invention, utilizing the action of such an oil pit,
This is to solve the above-mentioned problem in suppressing the transfer of the grinding streaks.

That is, according to the present invention, the degree of the oil pits is influenced by the roll diameter, the viscosity of the rolling oil, etc., and when the roll diameter is large and the rolling oil viscosity is high, oil pits are likely to occur and rolling is performed. Paying attention to the fact that the optical anisotropy of the plate is reduced, by adopting the above-mentioned configuration, the roll roughness and the rolling reduction are reduced to reduce the plate surface streaks and reduce the diffuse reflection in the plate width direction. At the same time, the diffuse reflection in the rolling direction was improved in the oil pits that occurred at the same time, so that the characteristic difference between the rolling direction and the width direction could be effectively reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when an aluminum plate or an aluminum alloy plate having a predetermined thickness is manufactured, a corresponding aluminum ingot or aluminum alloy ingot is used, and it is hot rolled according to a conventional method. The rolling is carried out, and then cold rolling is carried out. The final pass rolling operation in this cold rolling is performed with a roll diameter of 200 mmφ or more and an average roughness in the roll axial direction: Ra.
Is 0.35 μm or less, and the viscosity is 2
Using rolling oil of not less than centistokes, at a rolling reduction of 35% or less: r, the average roughness: Ra (μm) and the rolling reduction: r (%) are expressed by the following formula: r ≦ −300 × Ra + 1.
It was done so as to satisfy the relationship of 25.

Thus, in the final pass rolling operation,
The average roughness in the roll axial direction: Ra is 0.35 μm or less, while the rolling reduction ratio: r is 35% or less, and by making them satisfy the relationship of the above equation, the grinding wire of the roll is Therefore, the plate surface streaks caused by the transfer of the sheet can be reduced, and the diffuse reflection in the plate width direction can be effectively reduced. Such an effect can be achieved particularly advantageously by setting the average roughness in the roll axis direction: Ra to 0.30 μm or less and the final pass rolling reduction: r to 20% or less.

Further, by setting the roll diameter of the rolling roll in the final pass rolling operation to 200 μmφ or more and setting the viscosity of the rolling oil to 2 centistokes (normal temperature) or more, the transfer of the grinding streaks of the rolling roll is weakened, Effectively increasing the oil pit, at the oil pit,
By increasing the diffuse reflection in the rolling direction, the difference in light reflection characteristics between the rolling direction and the width direction on the plate surface can be advantageously reduced. The upper limit of the roll diameter and the rolling oil viscosity of those rolling rolls can be appropriately defined according to the model of the cold rolling mill, but in the practical range,
A roll having a diameter of about 500 mmφ and a rolling oil having a viscosity of about 8 centistokes (normal temperature) are used.

Further, in the present invention, in order to more effectively realize the diffuse reflection improvement in the rolling direction by the oil pit, the rolling speed in the final pass rolling operation is 300 m / min or more, preferably 1000 m / min.
m / min or more. By performing the final pass rolling at such a rolling speed, it is possible to effectively increase the oil pits.

The aluminum plate or aluminum alloy plate having a predetermined thickness obtained by cold rolling under such final pass rolling conditions has a light reflection characteristic in the rolling direction and in the width direction perpendicular to the rolling direction. Is effectively reduced, and thus the diffuse reflectance difference of 180 or less, which is the limit of malfunction of the optical inspection device in the processing step after the plate material, and the like. To do
It can be achieved advantageously.

The diffuse reflectance referred to here is 4 with respect to the plate surface, as shown in the schematic diagram of measurement in FIG.
The light emitted from the direction of 5 ° is 0 ° (perpendicular to the plate surface)
Percentage of diffuse reflection in all directions relative to the value on a perfect diffuse reflection surface (surface where the irradiation light is reflected uniformly in all directions)
In the above, such diffuse reflectance is obtained in the rolling direction of the plate material and the width direction perpendicular to it.
The optical anisotropy is evaluated by the difference between them.

[0017]

EXAMPLES In order to clarify the present invention in more detail, some examples of the present invention will be shown below.
It goes without saying that the present invention is not subject to any restrictions by the description of such embodiments. In addition to the following embodiments, the present invention is not limited to the above specific description, and various changes and modifications are made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It is to be understood that improvements, etc. can be added.

Example 1 First, an aluminum alloy having a plate thickness of 2 mm (material: 508)
2) The rolled material was prepared from the corresponding ingot of aluminum alloy by a normal hot rolling operation. Then, using this rolled material, various work rolls (rolling rolls) having different surface roughnesses were subjected to cold rolling operation under the following conditions to obtain an aluminum alloy plate having a thickness of 0.3 mm. Obtained. -Cold rolling conditions-Work roll diameter: 325 mmφ or 200 mmφ pass schedule: Rolling up to 0.3 mm in 4 to 5 passes. The final pass rolling reduction was 35% or 10%. Rolling speed: 500 m / min Rolling oil viscosity: 4 cst (centistokes)

The diffuse reflectances in the rolling direction and the width direction of various cold-rolled sheets thus obtained are shown in FIG.
Gloss meter manufactured by Murakami Color Research Laboratory according to the measurement method as follows:
The relationship between the diffuse reflectance difference obtained and the roughness in the roll axis direction: Ra is shown in FIG.

Example 2 An aluminum alloy plate having a plate thickness of 0.3 mm was obtained by cold rolling in the same manner as in Example 1 except that the final pass rolling conditions were changed. The final pass rolling condition is, as shown in Table 1 below, the average roughness in the roll axial direction of the rolling roll: R
a, final pass rolling reduction ratio: r, rolling roll diameter, rolling oil viscosity and rolling speed are variously varied, and the resulting rolling direction of the sheet material and the diffuse reflectance thereof in the width direction are respectively measured, The difference is also shown in Table 1 below.

[0021]

[Table 1]

As is clear from the results shown in Table 1, in the examples No. 1 to No. 10 according to the present invention, the average roughness Ra of the rolling roll in the axial direction: Ra is 0.35 μm.
And the final pass rolling rate to 35% or less,
The average roughness: Ra and the rolling reduction: r are expressed by the formula: r ≦ −30.
While satisfying the relationship of 0 × Ra + 125, the roll diameter of the rolling roll is 200 μmφ or more, and the rolling oil viscosity is 2 centistokes or more. By adopting such conditions, the diffuse reflectance can be increased. A plate material having a small difference is advantageously obtained.

On the other hand, as shown in Comparative Examples No. 21 to No. 26, the average roughness in the axial direction of the roll: Ra and the rolling reduction: r are out of the range of the present invention, or rolling When the roll diameter of the roll becomes smaller, or when the rolling oil viscosity becomes smaller than 2 centistokes, the difference in diffuse reflectance of the obtained plate material becomes large and the optical anisotropy becomes large.

[0024]

As is apparent from the above description, according to the present invention, the difference in the reflection characteristics between the rolling direction and the width direction perpendicular to the rolling direction, that is, the aluminum plate or the aluminum alloy plate having a small optical anisotropy is obtained. Since it has become possible to stably manufacture, by this, the occurrence of problems when introducing an optical inspection device in the subsequent processing steps of such a plate material can be effectively avoided. This is where the great technical significance of the present invention lies.

[Brief description of drawings]

FIG. 1 is an explanatory diagram schematically showing a method of measuring diffuse reflectance.

FIG. 2 is a graph showing the relationship between the diffuse reflectance difference of the aluminum alloy plate obtained in Example 1 and the roll axial roughness: Ra.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiro Kimura 5-11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd. (72) Inventor Motoya Kamito 5-11-3 Shimbashi, Minato-ku, Tokyo No. Sumitomo Light Metal Industry Co., Ltd.

Claims (2)

[Claims] 1. An aluminum ingot or an aluminum alloy ingot is hot-rolled and then cold-rolled,
When producing an aluminum plate or an aluminum alloy plate having a desired thickness, the final pass rolling operation in the cold rolling is performed by rolling with a roll diameter of 200 mmφ or more and an average roughness in the roll axial direction: Ra of 0.35 μm or less. Using a roll and a rolling oil having a viscosity of 2 centistokes or more, when the rolling reduction is r of 35% or less, the average roughness: Ra (μm) and the rolling reduction: r (%) are as follows: r ≦ −300 × Ra + 125
The method for producing an aluminum plate or an aluminum alloy plate having low optical anisotropy, characterized in that the above relationship is satisfied. 2. The final pass rolling operation is further 300 m
The method for producing an aluminum plate or an aluminum alloy plate according to claim 1, which is carried out at a rolling speed of not less than / min.