KR101965418B1 - Heat treatment method of aluminum alloy - Google Patents

Abstract

A method of heat-treating an aluminum alloy according to the present invention comprises: die-casting an aluminum alloy; Solidifying the die-cast aluminum alloy; And a step of precipitating and strengthening the solid solution strengthened aluminum alloy.
In addition, the heat treatment method of the aluminum alloy according to the present invention can increase the tensile strength by at least 25% while maintaining the elongation at least equal to that of the aluminum alloy die casting without heat treatment by applying the two-step heat treatment process.

Description

[0001] Heat treatment method of aluminum alloy [0002]

The present invention relates to a heat treatment method for an aluminum alloy, and more particularly, to a heat treatment method for improving the tensile strength of an aluminum alloy for die casting through a two-step heat treatment.

Aluminum alloys are divided into aluminum alloys for casting such as die casting and die casting, and aluminum alloys for plastic working such as extrusion and rolling, depending on the manufacturing method of the product. About 20% of all aluminum products are aluminum alloys for plastic working such as extrusion and rolling And about 80% is produced from aluminum alloy for casting. Therefore, aluminum alloy for casting is very high in aluminum industry.

Aluminum alloys for casting are divided into casting molds, casting alloys and die casting alloys, depending on the casting method. After casting, casting molds and mold casting alloys are improved in tensile strength of alloys by various heat treatment methods such as solid solution strengthening heat treatment and precipitation strengthening heat treatment. Table 1 shows the conditions of the solid solution strengthening heat treatment and the precipitation strengthening heat treatment of the aluminum alloy for casting mold. The solidification strengthening heat treatment temperature of the aluminum alloy for mold casting is 500 ° C or more, and the solid solution strengthening heat treatment time is 4 hours or more.

Alloy specification Employment Enhancement Processing Precipitation hardening treatment The tensile strength
(MPa) Elongation
(%) Temperature (℃) Time (minutes) Temperature (℃) Time (minutes) AC1A 515 600 160 360 255 2 AC1B 515 600 160 240 304 3 AC2A 510 480 160 540 275 One AC2B 500 600 160 300 245 One AC4A 525 600 160 540 240 2 AC4B 500 600 160 420 245 - AC4C 525 480 160 360 226 3 AC4D 525 600 160 600 275 One AC5A 520 420 200 300 294 - AC8A 510 240 170 600 275 - AC8B 510 240 170 600 275 - AC8C 510 240 170 600 275 - AC9A 500 240 200 240 196 - AC9B 500 240 200 240 275 -

Alloy specification Chemical composition (% by weight) Cu Si Mg Zn Fe Mn Ni Sn Al ADC 1 1.0 or less 11.0 to 13.0 0.3 or less 0.5 or less 1.3 or less 0.3 or less 0.5 or less 0.1 or less Remainder ADC 3 0.6 or less 9.0 to 10.0 0.4 to 0.6 0.5 or less 1.3 or less 0.3 or less 0.5 or less 0.1 or less Remainder ADC 5 0.2 or less 0.3 or less 4.0 to 8.5 0.1 or less 1.8 or less 0.3 or less 0.1 or less 0.1 or less Remainder ADC 6 0.1 or less 1.0 or less 2.5 to 4.0 0.4 or less 0.8 or less 0.4 to 0.6 0.1 or less 0.1 or less Remainder ADC 10 2.0 to 4.0 7.5 to 9.5 0.3 or less 1.0 or less 1.3 or less 0.5 or less 0.5 or less 0.3 or less Remainder ADC 12 1.5 to 3.5 9.6-12.0 0.3 or less 1.0 or less 1.3 or less 0.5 or less 0.5 or less 0.3 or less Remainder

However, the aluminum alloy for die casting shown in Table 2 is partially subjected to the stress relieving heat treatment at a temperature as low as 200 ° C or lower, and the solid solution strengthening heat treatment which requires heat treatment at a high temperature to apply the alloy element to the aluminum base metal is not applicable In fact.

The reason for this is that the die casting process is a method of casting a product by injecting molten metal into a mold at a high speed and a high pressure using a die casting apparatus, and in a process of injecting the molten metal into a mold at a high speed and a high pressure using a die casting apparatus Inevitably, atmospheric gas is mixed into the molten metal.

That is, a certain amount of atmospheric gas is mixed in the die casting product obtained by solidifying the molten metal injected into the die at a high speed and a high pressure. When the die casting product is heat-treated at a high temperature, the gas mixed in the die casting product is heated So that a bubble defect such as a blister occurs on the surface of the die casting product. Therefore, as a heat treatment method for improving the tensile strength of aluminum alloy die casting, most of the solid solution strengthening heat treatment and precipitation strengthening heat treatment are not applicable.

However, in the case of casting a product by injecting a molten metal into a die at a high speed and a high pressure by using a vacuum die casting device to minimize the atmospheric gas contained in the die casting product, a partial solution strengthening heat treatment and a precipitation strengthening heat treatment can be limited However, in such a vacuum die casting product, bubble defects such as blisters are generated on the surface of the die casting product when the heat treatment temperature for solid solution strengthening is high.

Recently, in the automobile industry, in order to respond to market demands such as reduction of automobile exhaust gas, improvement of energy efficiency, and light weight of automobile parts for improvement of output, a high strength aluminum die casting part having a high tensile strength as compared with the tensile strength of existing aluminum die casting parts Development is required.

In order to respond to market demands such as light weight and excellent surface characteristics for external parts such as housings, frames, and hinges, which are structural parts having a function of protecting electronic materials and modules of mobile devices such as mobile phones, High strength aluminum die casting parts with high tensile strength as compared with the tensile strength of aluminum die casting parts.

However, up to now, aluminum die-casting parts have been limited to the development of high-strength aluminum die casting parts for automobiles and electronics, because most of heat treatment such as solid solution strengthening and precipitation strengthening, which are necessary for improving tensile strength, are not applied. Accordingly, in order to apply to the development of high strength aluminum die casting parts for automobiles and electronics, there is a desperate need to develop a heat treatment technique of an aluminum alloy die casting which can maintain an elongation ratio equal to or more than the same level and at the same time increase tensile strength.

Korean Patent No. 10-1055373

DISCLOSURE OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of manufacturing an aluminum alloy for die casting, To an annealing method of an aluminum alloy which has an elongation of 5% or more.

On the other hand, other unspecified purposes of the present invention will be further considered within the scope of the following detailed description and easily deduced from the effects thereof.

According to an aspect of the present invention, there is provided a method of heat treating an aluminum alloy, comprising: die casting an aluminum alloy; Solidifying the die-cast aluminum alloy; And a step of precipitating and strengthening the solid solution strengthened aluminum alloy.

In the heat treatment method of the aluminum alloy according to an embodiment of the present invention, the heat treatment temperature of the solid solution strengthening may be more than 470 DEG C and 500 DEG C, and the heat treatment time may be 15 minutes to 1 hour.

In the heat treatment method of an aluminum alloy according to an embodiment of the present invention, the heat treatment temperature of the precipitation hardening may be 150 to 200 ° C and the heat treatment time may be 1 to 5 hours.

In the heat treatment method for an aluminum alloy according to an embodiment of the present invention, the aluminum alloy may have a tensile strength of 310 MPa or more and an elongation of 5% or more.

In the method of heat treatment of an aluminum alloy according to an embodiment of the present invention, the aluminum alloy contains 8 wt% or less of Zn (excluding 0), 13 wt% or less of Si (excluding 0), 2 wt% Not more than 2% by weight of Cu, not more than 0.5% by weight of Ti (excluding 0), not more than 1.0% by weight of Fe (excluding 0), and other unavoidable impurities.

The present invention also includes an aluminum alloy for die casting manufactured by the above-described heat treatment method of an aluminum alloy.

According to the heat treatment method of the aluminum alloy of the present invention, the aluminum alloy subjected to the precipitation hardening treatment for precipitating the alloy elements successively solved after the solid solution strengthening treatment by adjusting the solid solution strengthening treatment temperature and time, The tensile strength can be improved by at least 25% while maintaining the elongation equal to or higher than that of the aluminum alloy not subjected to the same heat treatment.

The heat treatment method of the aluminum alloy according to the present invention can be suitably used for manufacturing aluminum die casting parts for automobiles and electronics, which require high tensile strength.

On the other hand, even if the effects are not explicitly mentioned here, the effect described in the following specification, which is expected by the technical features of the present invention, and its potential effects are treated as described in the specification of the present invention.

FIG. 1 is a flowchart of a process of a heat treatment method of an aluminum alloy according to an embodiment of the present invention.

It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The scope of technical thought is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the scope of the invention to those skilled in the art. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The same reference numerals denote the same elements at all times. In this specification, terms such as "comprising" or "consisting of" are intended to specify the presence of stated features, integers, steps, operations, elements, parts or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

When an aluminum alloy product is manufactured by a conventional die casting process, there is a problem that tensile strength and elongation are low. In order to solve these problems, it is possible to apply the heat strengthening heat treatment and the precipitation strengthening heat treatment to the existing aluminum alloy die casting product to a limited extent. However, due to the heat treatment temperature and maintenance time which are not suitable for aluminum alloy die casting products, And so on.

Accordingly, the present applicant has developed a heat treatment method of an aluminum alloy which can improve the tensile strength at the same time while maintaining an elongation ratio equal to or higher than that of a conventional aluminum alloy die casting product.

A method of heat-treating an aluminum alloy according to an embodiment of the present invention comprises: die-casting an aluminum alloy; Solidifying the die-cast aluminum alloy; And a step of precipitating and strengthening the solid solution strengthened aluminum alloy.

That is, the present invention includes the die casting step, the solid solution strengthening step, and the precipitation hardening step, thereby improving the tensile strength of the aluminum alloy to 310 MPa or more, and the two-step heat treatment including the solid solution strengthening step and the precipitation hardening step It is possible to prevent a sharp decrease in elongation, which would otherwise occur.

Hereinafter, a method of heat-treating an aluminum alloy according to an embodiment of the present invention will be described in detail with reference to FIG.

FIG. 1 is a flowchart of a process of a heat treatment method of an aluminum alloy according to an embodiment of the present invention.

Referring to FIG. 1, a method for heat-treating an aluminum alloy according to an exemplary embodiment of the present invention may include a die casting step S100, a solid solution strengthening step S200, and a precipitation strengthening step S300.

Specifically, the die casting step S100 may be performed by injecting a molten metal of the above-described aluminum alloy into a mold and then pressing it into a desired shape.

Next, the solid solution strengthening step S200 may mean solidifying the aluminum alloy produced at the die casting step S100 at a predetermined temperature.

In detail, in the heat treatment method of the aluminum alloy according to an embodiment of the present invention, the heat treatment temperature of the solid solution strengthening may be 450 to 500 ° C, and the heat treatment time may be 15 minutes to 1 hour.

If the heat treatment temperature for the solid solution strengthening is higher than 500 ° C, the strength and elongation of the aluminum alloy without solid solution strengthening heat treatment can be lowered.

When the solid solution strengthening treatment temperature of the aluminum alloy die casting is less than 450 ° C, since the alloy element is diffused into the aluminum matrix and the thermal energy for supersaturated alloying element is insufficient, the alloy element solidified after the solid solution strengthening treatment is precipitated There is a problem in that precipitation hardening effect for obtaining a strengthening effect is hardly exhibited.

On the other hand, when the solid solution strengthening treatment temperature of the aluminum alloy die casting is performed at a temperature of not less than 450 ° C. and not more than 500 ° C., and when the solid solution strengthening treatment time exceeds one hour, coarsening of crystal grains occurs inside the aluminum base , The strength and elongation of the heat-treated aluminum alloy die casting may be lower than the strength and elongation of the aluminum alloy die casting not subjected to the solid solution strengthening heat treatment.

When the solid solution strengthening treatment temperature of the aluminum alloy die casting is in the range of 450 to 500 ° C. and the solid solution strengthening treatment time is less than 15 minutes, the alloy element diffuses into the aluminum matrix, There is a problem that the precipitation strengthening effect for obtaining the strengthening effect by precipitation of the alloy element solidified after the solid solution strengthening treatment hardly appears.

Lastly, the precipitation strengthening step (S300) may mean precipitation strengthening of the aluminum alloy produced in the solid solution strengthening step (S200).

In detail, in the method for annealing an aluminum alloy according to an embodiment of the present invention, the precipitation strengthening step is performed at a temperature lower than the heat treatment temperature at the time of strengthening the solid solution, and the alloy element precipitated in the solid solution strengthening step It can mean a step.

According to a preferred embodiment of the present invention, the heat treatment temperature of the precipitation hardening may be 150 to 200 ° C, and the heat treatment time may be 1 to 5 hours.

Specifically, when the heat treatment temperature for the precipitation strengthening exceeds 200 占 폚, the precipitation phase described above becomes excessively coarse, and the growth effect of the crystal grains can be lowered.

When the heat treatment temperature for precipitation strengthening is less than 150 ° C, the precipitation strengthening effect is lowered and the effect of increasing the strength may be insignificant.

In addition, if the precipitation strengthening treatment time is longer than 5 hours, the precipitation strengthening heat treatment temperature is set to 150 to 200 ° C. However, when the precipitation strengthening treatment time exceeds 5 hours, coarsening of crystal grains occurs inside the aluminum base.

When the precipitation strengthening treatment time is less than 1 hour, the precipitation strengthening effect is lowered and the effect of increasing the strength may be insignificant.

On the other hand, the precipitation phase is precipitated in the precipitation hardening step _{(S300) MgZn 2, Al 3} Ti, Al 3 Fe, Mg 2 Si, Al 2 may be an such as Cu, but the invention is not limited to the type on the precipitation.

Meanwhile, in the method for annealing an aluminum alloy according to an embodiment of the present invention, it may include a quenching step of quenching the solid solution strengthened aluminum alloy between the solid solution strengthening step (S200) and the precipitation strengthening step (S300).

The quenching step may be a method commonly used in the art. For example, the quenching may be performed by immersing the solid solution strengthened aluminum alloy in oil or water and quenching it to room temperature. In describing the present invention, the ambient temperature may be a temperature of natural or unheated or non-warmed temperature, for example, a temperature of about 10 to 30 캜, about 15 to 30 캜, about 20 to 30 캜, 23 캜, . ≪ / RTI >

Hereinafter, the above-described aluminum alloy will be described in detail.

In order to accomplish the object of the present invention, the aluminum alloy for die casting may be an Al-Zn-based alloy or an Al-Si-based alloy for achieving the object of the present invention described above. Based alloys.

In detail, the aluminum alloy may contain pure aluminum in an amount of 75 to 95% by weight based on the total weight of the aluminum alloy. At this time, the aluminum alloy may include one or more selected from Zn, Si, Mg, Cu, Ti, and Fe, but the present invention is not limited thereto.

In the method of heat treatment of an aluminum alloy according to an embodiment of the present invention, the aluminum alloy contains 8 wt% or less of Zn (excluding 0), 13 wt% or less of Si (excluding 0), 2 wt% Not more than 2% by weight of Cu, not more than 0.5% by weight of Ti (excluding 0), not more than 1.0% by weight of Fe (excluding 0), and other unavoidable impurities.

Particularly, when Si (silicon) is 13 wt% or less, it is good for improving the tensile strength of the aluminum alloy. However, when Si is more than 13 wt%, a brittleness eutectic Si phase is generated, It is possible to lower the tensile strength.

If Cu is less than 2% by weight, the tensile strength and elongation of the aluminum alloy may be improved. If Cu is more than 2% by weight, however, a coarse precipitate,? -Al ₂ Cu phase, So that the tensile strength of the aluminum alloy can be lowered.

When the amount of Ti (titanium) is 0.5% by weight or less, it is added to aluminum as an alloying element and precipitated on an aluminum base metal with an intermetallic compound such as Al ₃ Ti by precipitation hardening heat treatment to increase the tensile strength. If the amount of Ti exceeds 0.5 wt%, the tensile strength and elongation of the aluminum alloy may be lowered.

When Fe (iron) is 1.0 wt% or less, it can be added to aluminum to increase the tensile strength while minimizing deterioration of the thermal conductivity of aluminum, and at the same time, it is possible to reduce mold seizure when molding an aluminum alloy product by die casting. If the content of Fe exceeds 1.0% by weight, the Fe-rich image (Fe-rich phase) may be excessively crystallized in the cast alloy to lower the main composition of the alloy.

Meanwhile, according to a preferred embodiment of the present invention, the aluminum alloy for die casting may be an Al-Zn-based aluminum alloy.

In detail, the Al-Zn-based aluminum alloy contains 5 to 7 wt% of Zn, 1 to 2 wt% of Mg, 0.1 to 0.3 wt% of Ti, 0.05 to 0.15 wt% of Fe, 0.1 wt% Impurities.

As described above, Zn (zinc) is an alloy element that can be added to aluminum as an alloy element to improve the casting composition and increase the tensile strength in accordance with the effect of solidification and precipitation strengthening. In the Al-Zn-based aluminum alloy according to an embodiment of the present invention, it is preferable that zinc is added in an amount of 5 to 7 wt%. If the zinc content is less than 5 wt%, the tensile strength of the cast alloy becomes low, Strength can not be obtained, and if the content of zinc exceeds 7% by weight, the casting may be lowered and the elongation may be lowered.

The magnesium (Mg) is an element that can be added to aluminum as an alloy element to improve the casting composition and increase the tensile strength according to the effect of solidification and precipitation strengthening. It is preferable that 1 to 2% by weight of magnesium is added to the Al-Zn-based aluminum alloy according to an embodiment of the present invention. If the content of magnesium is less than 1% by weight, the tensile strength of the cast alloy becomes low, Strength can not be obtained. When the content of magnesium exceeds 2% by weight, the main composition may be lowered and the elongation may be lowered.

As described above, the Fe (iron) has a very low solubility in an aluminum base metal at room temperature and is extremely low as 0.052% by weight. After casting, most of it is crystallized as an intermetallic compound such as Al ₃ Fe, Is an alloy element capable of increasing the strength while minimizing deterioration and at the same time capable of reducing die squeeze when molding an aluminum alloy product by die casting. It is preferable that 0.05 to 0.15% by weight of iron is added to the Al-Zn-based aluminum alloy according to an embodiment of the present invention. If the content of iron is less than 0.05% by weight, the effect of preventing die- (Fe-rich phase) is excessively pored out in the casting alloy when the content of iron exceeds 0.15% by weight, so that the amount of the Fe- Can be reduced.

As described above, Ti (titanium) is an alloy element which is added as an alloy element to aluminum and precipitated on an aluminum base metal with an intermetallic compound such as Al ₃ Ti by precipitation hardening heat treatment to increase the tensile strength, and It is an alloy element which can be added to aluminum as an alloy element to obtain the effects of grain refinement, alloy fluidity and crack prevention of the cast material. In order to achieve the object of the present invention, it is preferable that 0.1 to 0.3% by weight of Ti is added. When the content of Ti is less than 0.1% by weight, the improvement of tensile properties such as tensile strength and elongation is insignificant. When the content of Ti is more than 0.3% by weight, tensile strength and elongation may be lowered.

In the description of the present invention, unavoidable impurities are impurities which are unintentionally mixed by a raw material or a manufacturing apparatus in the process of producing the aluminum alloy according to the present invention. For example, Cu, Cr, Co, V, Mn, Li, Ni, Sn, Pb and the like. These impurity components can be kept at 0.1 wt% or less, preferably 0.01 wt% or less, so as not to affect the alloy characteristics.

The present invention also includes an aluminum alloy for die casting manufactured by the above-described heat treatment method of an aluminum alloy.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the following examples.

Examples 1 to 2 and Comparative Examples 1 to 6

An aluminum alloy raw material was prepared so as to have the composition shown in Table 3, and then charged into a melting and stirring type melting furnace to dissolve the aluminum alloy first in the atmosphere. Thereafter, the molten aluminum alloy melt was die cast using a die casting apparatus and a die casting die.

Unit: wt% Zn Si Mg Cu Ti Fe Al Alloy 1 6.01 0.05 1.40 - 0.21 0.08 Honey. Alloy 2 0.69 10.18 0.13 1.69 0.02 0.79 Honey.

Thereafter, the die cast aluminum alloy test piece was solidified by using an electric resistance heat treatment furnace. After the solid solution strengthening treatment, water cooling and precipitation strengthening treatment were continuously carried out to produce a final aluminum alloy test piece.

Details of the solid solution strengthening treatment and precipitation hardening treatment are listed in Table 4 below.

Alloy type Employment Enhancement Processing Precipitation hardening treatment Temperature (℃) Time (minutes) Temperature (℃) Time (minutes) Comparative Example 1 Alloy 1 - - - - Comparative Example 2 480 30 - - Comparative Example 3 510 20 - - Example 1 480 30 150 180 Comparative Example 4 510 20 150 180 Comparative Example 5 Alloy 2 - - - - Comparative Example 6 480 30 - - Comparative Example 7 510 20 - - Example 2 480 30 200 180 Comparative Example 8 510 20 200 180

Measurement example: Evaluation of tensile properties

In order to evaluate the tensile properties of the aluminum alloys prepared in Examples 1 to 2 and Comparative Examples 1 to 8, tensile strength and elongation were measured and listed in Table 5 below. The measurement of tensile strength and elongation was carried out by a method commonly used in this field.

Alloy type Tensile Strength (MPa) Elongation (%) Comparative Example 1 Alloy 1 278 7 Comparative Example 2 302 15 Comparative Example 3 220 4 Example 1 450 7 Comparative Example 4 245 2 Comparative Example 5 Alloy 2 247 3 Comparative Example 6 272 6 Comparative Example 7 182 One Example 2 316 5 Comparative Example 8 188 One

As shown in Table 5, the aluminum alloy according to Example 1 of the present invention had a tensile strength increased by about 49% and an elongation decreased by about 53% compared to Comparative Example 2 described above. However, the elongation percentage of the aluminum alloy according to Example 1 of the present invention was equivalent to that of Comparative Example 1, and the tensile strength was increased by about 62%. Here, in Comparative Example 2, only the solid solution strengthening treatment was carried out at a temperature of 480 占 폚 for 30 minutes. In Comparative Example 1, the solid solution strengthening treatment and the precipitation hardening treatment were not carried out.

In addition, in Comparative Example 4, the tensile strength was reduced by about 19% and the elongation was reduced by about 87% as compared with the aluminum alloy according to Example 1 of the present invention. In Comparative Example 4, the alloy 1 was subjected to solid solution strengthening treatment at a temperature of 510 ° C for 20 minutes and then precipitation strengthening treatment at a temperature of 150 ° C for 3 hours.

In addition, the aluminum alloy according to Example 2 of the present invention had a tensile strength increased by about 16% and an elongation decreased by about 17% compared to Comparative Example 6 described above. However, the elongation percentage of the aluminum alloy according to Example 2 of the present invention was increased by about 67% and the tensile strength was increased by about 28% as compared with Comparative Example 5. Here, in Comparative Example 5, only the solid solution strengthening treatment was performed at a temperature of 480 캜 for 30 minutes, and the solid solution strengthening treatment and the precipitation hardening treatment were not performed in Comparative Example 6.

In addition, in Comparative Example 8, the tensile strength was reduced by about 31% and the elongation was reduced by about 83% as compared with the aluminum alloy according to Example 2 of the present invention. In Comparative Example 8, the alloy 2 was subjected to solid solution strengthening treatment at a temperature of 510 ° C for 20 minutes and then precipitation strengthening treatment at a temperature of 150 ° C for 3 hours.

In summary, the aluminum alloy according to the present invention is subjected to solid solution strengthening treatment by adjusting the solid solution strengthening treatment temperature and time after die casting, and thereafter performing precipitation strengthening treatment for precipitating successively solidified alloy elements, The tensile strength can be improved by about 28% while maintaining the elongation at least equal to that of the aluminum alloy not subjected to the strengthening treatment.

Accordingly, the heat treatment method of the aluminum alloy according to the present invention can be suitably used for manufacturing aluminum die casting parts for automobiles and electronics requiring high tensile strength.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (6)

(Excluding 0), Zn 2 wt% or less (excluding 0), Cu 2 wt% or less, Ti 0.5 wt% or less (excluding 0), Fe 1.0 wt% (Exclusive of 0) and other unavoidable impurities;
Heat-strengthening the die-cast aluminum alloy at a temperature higher than 470 DEG C and lower than 500 DEG C; And
Hardening aluminum alloy at 150 to 200 DEG C,
A tensile strength of 310 MPa or more, and an elongation of 5% or more.
The method according to claim 1,
Wherein the solid solution strengthening heat treatment time is from 15 minutes to 1 hour.
The method according to claim 1,
Wherein the heat treatment for the precipitation strengthening is performed for 1 to 5 hours.
delete delete An aluminum alloy for die casting produced by the method of any one of claims 1 to 3.

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