JPH0357504A - Aluminum alloy sheet excellent in clarity and suitable for press-forming - Google Patents

Abstract

PURPOSE:To improve the clarity after painting without deteriorating workability excellent in R.D.C by specializing the roughness of a flat part other than a deut part transferred from rolling rolls. CONSTITUTION:The surface property of aluminum alloy sheet is adjusted by the rolling rolls whose surface is adjusted by laser beam machining. The state of the surface of a rolled sheet is composed of the deut part 1 arranged in adequate diameter and the flat part 2 other than it. The diameter and pitch of the deut part 1 have a large influence on the clarity after painting and press formability and when the area factor of the flat part is larger, the clarity is improved but the press formability is deteriorated. For that purpose, the roughness of the flat part 2 other than the impression part 1 transferred from the rolling rolls is given by <= 0.35 mum in Ra. Consequently, the clarity can be improved by adjusting the surface property without deteriorating the characteristics of R.D.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an aluminum alloy plate for stamping, and particularly to an aluminum alloy rolled plate with excellent appearance (sharpness) after painting.

(Prior art and problems to be solved) Conventionally, aluminum alloy rolled plates used for press forming include those with a dull finish (D.C.), and those with a dull finish that is rougher than the above-mentioned dull finish. (R.D.C.) are mainly used in durable consumer goods such as automobiles and home appliances.

In particular, in materials for automobiles and home appliances, R.I. D. C. The surface was roughened using a rolling roll for R. D. C. An aluminum alloy plate with a finished surface is used.

However, in recent years, as general consumers have become more sophisticated, more emphasis has been placed on the appearance after painting, especially the sharpness of the image. However, it has become difficult to provide the required appearance, especially good image clarity. For this reason, the above R.
D. C. There has been a need for an aluminum alloy rolled sheet that has improved image clarity without deteriorating its excellent properties.

The present invention has been made in response to the above-mentioned demands, and is intended to meet the needs of R. D. C. The object of the present invention is to provide an aluminum alloy plate for press forming that has excellent image clarity after painting without deteriorating the excellent properties of the aluminum alloy plate.

(Means for Solving the Problems) In order to achieve the above object, the present inventor has conducted extensive research on measures to adjust the surface properties of aluminum alloy plates for certain uses.

As a result, the R. D. C. After gaining the knowledge that the sharpness of the image could be improved without deteriorating the characteristics of the surface, we conducted further experimental research on how to adjust the surface texture, determined the adjustment standards, and first filed a patent application in 1983.
-192938 was proposed. That is, this aluminum alloy plate for press forming is an aluminum alloy plate rolled using a laser-processed rolling roll, and the diameter of the circular indentation transferred from the rolling roll is 1.
It is desirable that the plate has a pitch of 00-300 μm, a pitch of 150-500 μm, an area ratio of a flat portion without an indentation of 60% or more, and a minute waviness of the plate of 1 μm or less.

However, as a result of subsequent experimental research, the smaller the roughness Ra of the flat part excluding the circular indentation, the better the image sharpness after painting. It has been found that this is the most excellent case, and the present invention has been made here.

The present invention will be explained in more detail below.

(Function) As mentioned above, in the conventional method for adjusting the surface properties of an aluminum alloy plate, the surface of the aluminum alloy rolled plate was given a dull finish by using a rolling roll roughened by shot peening or the like, but in the present invention, The surface properties of the plate are adjusted using a rolling roll whose surface has been conditioned by laser processing.

At that time, the roughness (Ra) of the flat part without any indentation is used as the adjustment standard for the surface texture between the circular indentation transferred to the rolled plate and the flat part without this indentation. ,
evaluate.

As shown in FIG. 1, the surface of the rolled plate is composed of indentations (concavities) 1 arranged at appropriate diameters and pitches and other flat areas 2. The diameter and pitch of the indentation part 1 have a great influence on the image clarity after painting and the press forming processability.The larger the pinch and the smaller the diameter, that is, the larger the flat area ratio, the more
Although the image clarity is improved, there is a problem in that the press moldability is deteriorated.

As a result of conducting experiments to solve the contradictory problems of improving image clarity and decreasing press formability by controlling the diameter and pitch of the indentation part 1, we found that the image clarity after painting was as follows: It has been found that this is also caused by the surface roughness of the flat area where there are no indentations, and by controlling the surface roughness of the flat area, it is possible to improve image clarity without deteriorating press formability. There was found.

Surface roughness charts (schematic diagrams) are shown in FIGS. 2 and 3. In this figure, the roughness (Ra) of the flat part is 0.35 μ■
If the conditions are as follows, excellent image clarity will be ensured after painting.

However, if the thickness exceeds 0.35 μm, excellent image clarity cannot be ensured.

Of course, it goes without saying that the diameter of the indentation, the pitch, the area ratio of the flat portion, etc. should be appropriately controlled. The diameter of the indented portion is preferably 100 to 300 μm, the pitch is preferably in the range of 4150 to 500 μm, and the area ratio of the flat portion is preferably 60% or more. Furthermore, the minute waviness of the plate is reduced to 1μ.
It is desirable to keep the temperature below the maximum.

Note that the material of the aluminum alloy of the present invention is not particularly limited, and various types of compositions can be used depending on the application. It goes without saying that other rolling conditions, coating conditions, etc. are not limited.

Next, examples of the present invention will be shown.

(Example) A rolled plate made of AQ-Mg aluminum alloy (thickness: 1.0 mm) equivalent to JIS 5182 was rolled using a rolling roll with various polishing conditions and laser processing conditions, and the surface of the flat part was rolled. The roughness was measured to evaluate the image clarity after painting. The evaluation results are shown in Table 1 and Figure 4.

Note that the surface roughness Ra was measured using a surface roughness measuring instrument (Surfcoder S).
E-30D). In addition, the sharpness was determined by applying a subcoat (C cationic electrodeposition), an intermediate coating (spray coating), and a top coating (spray coating) after zinc phosphate treatment, using a sharpness gloss meter (P
GD) was evaluated.

In Table 1, the present invention materials No. 1 to Nα2 are B. C. (Bryl-) Roll (
D. C. After rolling the flat part with B
．． C. This is an example of finish rolling with a laser-treated roll finished to the same level as a roll, and the present invention materials Nα3 to No. 4 is the flat part roughness of the laser processed Erol. C. This is an example of rolling finished to the same level as a roll.

In addition, for comparison materials No. 5 to Nn 7, the flat part of the laser processing roll was D. C. This is an example of rolling finished to the same level as a roll.

The comparative material NCL8 is R. D. C. This is a conventional material rolled with standard rolling rolls.

As is clear from the construction table and Fig. 4, the invention material No.
All of No. 1 to No. 4 had good image clarity while maintaining press moldability compared to the comparative materials.

On the other hand, like comparative materials &5 to No.7, even if the diameter and pitch of the indented portions were appropriate, the image clarity was not good.

[Margin below] (Effect of the invention) As detailed above, by applying the present invention, the roughness Ra of the flat part can be reduced to 0.35 using a laser-processed rolling roll.
If adjusted so that it is below μm, the R. D. C. It is possible to obtain an aluminum alloy plate for press forming with excellent image clarity after coating without deteriorating the excellent workability of the aluminum alloy plate.

[Brief explanation of drawings]

Figure 1 is a diagram showing indentations and flat areas on the surface of a rolled plate, Figure 2 is a schematic diagram of a roughness chart when the rolled plate surface in direction A in Figure 1 has indentations and flat areas, and Figure 3 The figure is B in the construction drawing.
FIG. 4 is a schematic diagram of a roughness chart when the surface of a rolled plate has a flat portion, and FIG. 4 is a diagram showing the relationship between the roughness of various rolled materials and the sharpness after painting in Examples. 1... Indentation part, 2... Flat part.

Claims (1)

[Claims] An aluminum alloy plate rolled using a laser-processed rolling roll, characterized in that the roughness of the flat portion other than the indented portion transferred from the rolling roll is 0.35 μm or less in Ra. Aluminum alloy plate for press forming with excellent properties.