KR100938652B1 - Aluminum alloy for display frame and keypad frame of personal digital assistant and the display frame and the keypad frame of cellular phone using the same - Google Patents

Abstract

The present invention is castability, molding precision. Provided are an aluminum alloy for a display frame and a keypad frame of a portable information terminal having improved surface treatment property and tensile strength. The aluminum alloy comprises 7.0 to 8.0 wt% of Si, 2.3 to 2.7 wt% of Mg, 1.2 to 1.9 wt% of Cu, 0.5 to 0.65 wt% of Fe, 0.2 to 0.5 wt% of Mn, and the remaining Al. . The aluminum alloy was formed from a specimen of 3.6 cm * 3.6 cm in width and length, and then subjected to a load of 1 kgf at a speed of 6 mm per minute, resulting in a yield strength of 9.0 to 9.3 kgf. The aluminum alloy according to the present invention is effective for the manufacture of display frames and keypad frames of mobile phones requiring precision.

Aluminum alloy, magnesium, silicon, display frame, keypad frame

Description

Aluminum alloy for display frame and keypad frame of portable information terminal and display frame and keypad frame of mobile phone using the same.

The present invention relates to an aluminum alloy for a display frame and a keypad frame of a portable information terminal, and includes castability and molding precision. The present invention relates to a display frame and a keypad frame of a portable information terminal having improved surface treatment property and tensile strength, and also to a display frame and keypad frame of a mobile phone using the aluminum alloy.

Recently, due to the development of the electronics industry and the communication industry, various electronic devices have been mass-produced. In particular, portable information terminals such as mobile phones, laptops, PDAs, etc., which can be carried by individuals, have been widely used. Due to the mass production and development of such portable devices, research and development and interest in their performance and functions are heightening, and there is a trend of increasing interest in the quality of internal and external materials such as cases, frames, and brackets constituting them. The materials currently widely used as interior and exterior materials of such devices include nonferrous metal alloys based on magnesium and aluminum.

The reason why such aluminum magnesium alloy is widely used is that magnesium has high activity, high risk of ignition in processing such as casting and polishing, and high strength and corrosiveness, but such disadvantages can be stabilized by aluminum.

In addition, such aluminum magnesium alloy can improve the mechanical properties, by adding Mn to further improve the corrosion resistance, due to the addition of Mn can reduce the amount of addition of Fe, Cu, Ni, The addition of Ag can improve the heat resistance strength, the addition of Zn improves the corrosion resistance and strength, the addition of Si improves the creep strength, and the addition of Th or Y results in mechanical refinement of the grains when coexisting with Zr. Due to the improved properties, such an aluminum magnesium alloy is widely used.

Moreover, the addition of rare earth elements to magnesium alloys improves casting properties, prevents oxidation during melting and casting, and also improves strength. Such rare earth elements have little effect on tensile properties at room temperature when only rare earth elements are added, because the grain size is large in binary alloys, and when Zr is added with rare earth metals, these coarse grains are refined. It is known to result in an increase in strength due to grain refinement.

On the other hand, as a recently known aluminum-magnesium alloy, there is a Korean Patent No. 10-0741660, the aluminum-magnesium alloy of this patent is Mg 11-14%, Fe 0.5% or less, Si0.01-0.5%, Mn 0.1 -0.5%, Ti 0.01-0.3%, Co 0.01-0.2%, Be 0.003-0.02%, balance Al and other inevitable components are included.

Such aluminum magnesium alloys, by appropriately adjusting the content of the Mg-containing components, by performing the solution treatment to ensure the mass production of die casting of Al alloy, mobile phones and electronic products excellent in mechanical properties, particularly hardness and impact resistance As well as providing new material alloy for interior and exterior materials, it is also possible to die-cast using the common cold-chamber method, so that the post-treatment process is simple, mass production is possible, and it has high pure or Mg content in terms of processability, castability and price. Provides more efficient effects than alloys.

However, such a conventional aluminum magnesium alloy has excessive oxidation of magnesium due to the excessive content of magnesium, the molten by-products are excessively produced, and these by-products are incorporated into the product to form a surface of the surface treatment due to the generation of bubbles and mixtures There is a problem that a defect is caused.

And there is a problem that can not be applied to products that require accurate dimensions or precision due to the generation of bubbles and by-products.

In addition, when used in a precision product is required to go through a separate surface treatment process is not only an additional cost, there is an uneconomical disadvantage due to the increase in the overall unit price due to the rise in magnesium price.

Therefore, the present invention has been invented to solve the above-described problems, the main purpose of the present invention, to prevent the formation of molten by-products during the melting operation, and to block the formation of bubbles or mixture in the final product to improve the quality of the surface The present invention provides an aluminum alloy for a display frame and a keypad frame of a portable information terminal.

Another object of the present invention can be applied to a product requiring accurate dimensions or precision without any additional process, and can minimize the content of expensive magnesium, aluminum alloy for display frame and keypad frame of a portable information terminal To provide.

Another object of the present invention is to provide a display frame and a keypad frame of a portable information terminal made of an aluminum alloy, which has improved moldability, high tensile strength, and improved surface treatment.

These objects are composed of 7.0 to 8.0 wt% of Si, 2.3 to 2.7 wt% of Mg, 1.2 to 1.9 wt% of Cu, 0.5 to 0.65 wt% of Fe, 0.2 to 0.5 wt% of Mn, and Al balance. The aluminum alloy for the display frame and the keypad frame of the portable information terminal can be achieved.

According to one feature of the invention, Si is set to 7.5% by weight, Mg is set to 2.5% by weight, Cu is set to 1.55% by weight, Fe is set to 0.575% by weight, and Mn is 0.35% by weight. , Al is set to 87.525% by weight.

According to another feature of the present invention, the yield strength is 9.0 to 9.3 kgf as a result of applying a load of 1 kgf at a speed of 6 mm per minute after forming a specimen of 3.6 cm * 3.6 cm in width * length.

The above objects can also be achieved by a display frame and a keypad frame of a cellular phone made of aluminum.

As a result, according to the aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention, by controlling the content of Si, Mg, Cu, Fe, Mn contained in the aluminum alloy, molten metal spreadability, fine moldability By improving the surface treatment property, strength and rigidity, it can be used in various manufacturing of various mechanical elements or parts requiring precision, and there is an effect of reducing the amount of expensive components.

In addition, there is an advantage that can be effectively used to manufacture the display frame and keypad frame of the mobile phone due to such effects.

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Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention basically includes aluminum, and the amount thereof is included in a relatively large proportion than other components described later.

In more detail, the aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention is basically Si 7.0 ~ 8.0 wt%, Mg 2.3 ~ 2.7 wt%, Cu 1.2 ~ 1.9 wt%, Fe 0.5 ~ 0.65 wt %, Mn 0.2 to 0.5% by weight, the balance is preferably composed of Al. Here, Al may be actually set to 86.25 ~ 88.8% by weight.

Of course, the above-described aluminum alloy for display frame and keypad frame of the portable information terminal may have a component that can be inevitably included in the manufacturing, but the content thereof is omitted or omitted because it is very small or insignificant.

The aluminum alloy for the display frame and the keypad frame of the portable information terminal according to one preferred embodiment of the present invention, Al 86.72 ~ 88.13 wt%, Si 7.2 ~ 7.8 wt%, Mg 2.45 ~ 2.62 wt%, Cu 1.35 ~ 1.80 wt %, 0.52 to 0.61 weight percent Fe, 0.35 to 0.45 weight percent Mn.

The aluminum alloy for display frame and keypad frame of the most preferred portable information terminal according to the present invention, Al is set to 87.525% by weight, Si is set to 7.5% by weight, Mg is set to 2.5% by weight, Cu is 1.55 It is set in weight percent, Fe is set at 0.575 weight percent, Mn is set at 0.35 weight percent.

When explaining the components of the aluminum alloy for the display frame and keypad frame of the portable information terminal according to the present invention in more detail, the reason for adding Si is included to improve the melt dispersibility and fine formability during casting.

Here, the reason for setting the amount of Si to 7.0 to 8.0% by weight is that less than 7.0% by weight of the melt dissipation is improved, but the fine moldability is lowered, while when exceeding 8.0% by weight, the fine moldability is improved, but the molten metal supply is lowered Can be.

The reason why Mg is set at 2.3 to 2.7% by weight is to improve surface treatment by preventing generation of by-products and surface defects due to excessive magnesium content as in the prior art. Experimental results show that when Mg is less than 2.3% by weight, the surface treatment property is further improved, but bubbles may be generated.

In addition, the reason for setting the Cu at 1.2 to 1.9% by weight is to improve the strength and stiffness, particularly the tensile strength. If the content is less than 1.2% by weight, the tensile strength may be lowered. It is improved but moldability may be lowered.

In addition, the reason for setting Fe to 0.5 to 0.65% by weight is to improve the tensile strength in addition to Cu. If the content is less than 0.5% by weight, the tensile strength is insignificant, while when it exceeds 0.65% by weight, the tensile strength becomes excessive. There may be a risk of corrosion.

In addition, the reason why Mn is set at 0.2 to 0.5% by weight is to improve the elongation and yield strength. If the content is less than 0.2% by weight, the elongation may increase while the yield strength may decrease. While yield strength can be improved.

Optionally, the aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention may include, for example, less than 0.4% by weight of Zn in order to further improve castability and improve the frequency of use of the mold.

Hereinafter, the present invention will be described in detail through examples.

Example 1

The aluminum alloy (Al + Mg (KGD)) for the display frame and the keypad frame of the portable information terminal according to the present invention, and the alloy according to the KS standard available as shown in Table 1 below * width * length 3.6cm * 3.6cm After the experiment was repeated 20 times to form a specimen of 1kgf at a speed of 6mm per minute and the average of the results are shown in the following graph and Table 2.

The aluminum alloy for display or keypad frame (Al + Mg (KGD)) of the portable information terminal according to the present invention is 87.525% Al, 7.5% Si, 2.5% Mg, 1.55% Cu, 0.575% Fe, 0.5n Composed of 0.35% by weight.

Table 1

Sample Name Cu Si Mg Zn Fe Mn Ni Sn Pb Ti ALDC8.1 3.0-5.0 5.0-7.0 0.3 ↓ 1.8 ↓ 0.9 ↓ 0.2-0.6 0.3 ↓ 0.1 ↓ 0.2 ↓ 0.2 ↓ ALDC7.1 0.10 ↓ 4.5-6.0 0.1 ↓ 0.1 ↓ 0.9 ↓ 0.5 ↓ 0.1 ↓ 0.1 ↓ 0.1 ↓ 0.2 ↓ ALDC12.1 1.5-3.5 9.6-12.0 0.3 ↓ 1.0 ↓ 0.9 ↓ 0.5 ↓ 0.5 ↓ 0.2 ↓ . . ALDC12Z.1 1.5-3.5 9.6-12.0 0.3 ↓ 3.0 ↓ 0.9 ↓ 0.5 ↓ 0.5 ↓ 0.2 ↓ . .

* Components other than those indicated in the samples in Table 1 (residue) are aluminum.

TABLE 2

sample Max. Strength (kgf) Load at 1mm (kgf) Al + Mg (KGD) alloy (present invention) 9.2 5.7 ALDC8.1 6.1 3.9 ALDC7.1 5.3 3.4 ALDC12.1 5.7 3.4 ALDC12Z.1 5.5 3.4

Table 3 shows the strength and stiffness of the ALDC12Z.1 alloy.

TABLE 3

sample Strength Stiffness Al + Mg (KGD) Alloy 62% excellent 67% excellent ALDC8.1 11% excellent 14.5% Excellent ALDC7.1 Similarity Similarity ALDC12.1 Similarity Similarity

As shown in Table 3 above, the aluminum alloy (Al + Mg (KGD)) for the display or keypad frame of the portable information terminal according to the present invention is stronger than the existing ALDC12Z.1 alloy, ALDC12.1 alloy, and ALDC7.1 alloy. Is more than 62% and the stiffness is more than 67%, and also 51% stronger and 53% better than ALDC8.1 alloy. As such, the reason why the strength and rigidity of the aluminum alloy according to the present invention is improved is that the tensile strength is increased due to the compound composition of Al ₂ and Cu ₃ according to the addition of a controlled amount (1.55% by weight) of Cu. .

In addition, although the aluminum alloy and other alloys for the display frame and the keypad frame of the portable information terminal according to the present invention contain some of the same components, it has been shown that excellent strength and rigidity can be maintained by adjusting the content. That is, by adjusting the amount of Si contained in the aluminum alloy to 7.5% by weight, the melt spreadability and fine formability are improved, and when the amount of Mg is adjusted to 2.5% by weight, the surface treatment property is improved, and Fe is 0.575% by weight. Tensile strength was further improved by adjusting, and when the amount of Mn was adjusted to 0.35% by weight, elongation and yield strength were improved.

Example 2

The aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention is set to 88.25 wt% Al, 7.2 wt% Si, 2.4 wt% Mg, 1.3 wt% Cu, 0.55 wt% Fe, 0.3 wt% Mn, The alloy of Table 1 was tested under the same conditions as in Example 1, and the strength of the ALDC12Z.1 alloy was increased by about 58%, and the stiffness was increased by about 63%.

Example 3

The aluminum alloy for the display frame and the keypad frame of the portable information terminal according to the present invention is set to 86.88 wt% Al, 7.8 wt% Si, 2.6 wt% Mg, 1.7 wt% Cu, 0.62 wt% Fe, 0.4 wt% Mn, The alloy of Table 1 was tested under the same conditions as in Example 1, and the strength of the ALDC12Z.1 alloy was increased by about 59% and the stiffness was increased by about 65%.

As can be seen from the above embodiments 2-3, if the composition ratio of each of the components within the composition ratio range of the components constituting the aluminum alloy for the display frame and keypad frame of the portable information terminal according to the present invention to the existing alloys It can be seen that the strength and rigidity are significantly increased or improved.

The aluminum alloy for the display frame and the keypad frame of the portable information terminal formed as described above may be effectively used for the manufacture of various mechanical elements and components that should be manufactured finely due to excellent meltability, improved surface treatment, and improved strength and rigidity. Can be.

In particular, as shown in the picture of Figure 1, as one of the components of the mobile phone which is a kind of portable information terminal that can be usefully used to manufacture a frame for supporting the display of the mobile phone and the frame for supporting the keypad.
While a preferred embodiment according to the present invention has been described above, it will be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the appended claims.

1 is a photograph showing a mobile phone display frame made of an aluminum alloy according to the present invention.

Claims (5)

Si 7.0 to 8.0 wt%, Mg 2.3 to 2.7 wt%, Cu 1.2 to 1.9 wt%, Fe 0.5 to 0.65 wt%, Mn 0.2 to 0.5 wt%, and the balance consists of Al; An aluminum alloy for a display frame and a keypad frame of a portable information terminal, characterized in that the yield strength is 9.0 to 9.3 kgf as a result of forming a specimen of 3.6 cm * 3.6 cm in width * length and applying a load of 1 kgf at a speed of 6 mm per minute. The display frame of claim 1, wherein Si is 7.5% by weight, Mg is 2.5% by weight, Cu is 1.55% by weight, Fe is 0.575% by weight, Mn is 0.35% by weight, and Al is 87.525% by weight. Aluminum alloy for keypad frame. The aluminum alloy of claim 1, further comprising at most 0.4 wt% of Zn. Display frame of a mobile phone made of the aluminum alloy according to any one of claims 1 to 3. Keypad frame of a mobile phone made of an aluminum alloy according to any one of claims 1 to 3.

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