KR102472890B1 - Aluminum alloy for casting having excellent thermal conductance, and casting method therefor - Google Patents

Abstract

An aluminum alloy for casting having excellent thermal conductivity is provided.
Casting aluminum alloy with excellent thermal conductivity of the present invention, in weight%, silicon (Si): 3.5 ~ 7.0%, iron (Fe): 0.5 ~ 1.2%, titanium (Ti): 0.01 ~ 0.3%, carbon (C) : 0.005 to 0.015%, cerium (Ce): 0.1 to 0.3%, residual aluminum (Al) and other unavoidable impurities, including copper (Cu): 0.08% or less, manganese (Mn): 0.05% or less , Magnesium (Mg): 0.05% or less, Chromium (Cr): 0.1% or less, and Zinc (Zn): 0.1% or less, and satisfies relational expressions 1-4, respectively.

Description

Aluminum alloy for casting having excellent thermal conductance, and casting method therefor}

The present invention relates to an aluminum alloy that can be applied without limitation to various casting processes (gravity casting, squeeze casting, mold high-speed casting, semi-solid casting) and a casting method thereof, and more particularly, to equipment such as RRU, RRH, MMU, etc. It relates to an aluminum alloy with excellent thermal conductivity and a casting method that can be used for casting thin plates for the manufacture of heat sinks included in.

In general, a die casting casting method is mainly used to manufacture heat sinks for products such as various electric machine products. Such die casting is an investment casting method in which a casting identical to a mold is obtained by injecting molten metal into a mold accurately machined to completely match a required casting shape. In addition to the advantage that the dimensions of the casting obtained are accurate, this die casting method has excellent mechanical properties and is characterized in that mass production is possible.

Meanwhile, as aluminum alloys used for such die casting, Al-Si alloys and Al-Mg alloys having excellent castability are mainly used. However, in the case of Al-Si-based alloys or Al-Mg-based alloys, their castability is excellent, but their thermal conductivity is as low as 90 to 140 W/mK, so heat dissipation for electric, electronic, and automobile applications that require high thermal conductivity of 160 W/mK or more is required. The use of parts has been limited.

For heat dissipation parts that require such high thermal conductivity, die-casting products of pure aluminum with a very high thermal conductivity of 220W/mK or more are used in parts such as rotors for electric and electronic products. Pure aluminum has very excellent thermal conductivity However, since it has low tensile strength and poor castability, there is a limit to its application to structural parts that require excellent mechanical properties as well as thermal conductivity.

These die-casting products are used in various fields, but in particular, as a large amount of heat is generated from semiconductor components such as CPU and communication modules due to the increasing capacity of embedded antennas in communication network parts such as LTE/5G base stations and repeaters, Manufacturing of a heat sink capable of effectively dissipating generated heat has become important.

As a conventional material used in the manufacture of such a heat sink, Si9 (Sr) may be mentioned, and the Si9 (Sr) contains 8 to 9% by weight of Si, 0.5 to 0.7% by weight of Fe, 0.01 to 0.02% by weight of Sr, It has a composition of less than 0.03% by weight of other impurities and the balance of Al. However, the tensile strength of the heat dissipation product made of the above material is 230 N/mm2, yield strength 120 N/mm2, elongation 3%, and thermal conductivity 150 W/mk. There was a limit that it could not be effectively applied to the technology area being concentrated.

Republic of Korea Patent Publication 2013-0083183 (published on July 22, 2013) Republic of Korea Patent Publication 2013-0083184 (published on July 22, 2013)

The present invention is for casting with excellent thermal conductivity having thin plate casting (0.3T), high thermal conductivity (170 ~ 200W / mK) and yield strength (80 ~ 140N / mm2), which can be effectively used for manufacturing instruments such as 5G communication equipment An object of the present invention is to provide an aluminum alloy and a casting method thereof.

In addition, the technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned are clearly understood by those skilled in the art from the description below. It could be.

One aspect of the present invention,

In weight percent, silicon (Si): 3.5 to 7.0%, iron (Fe): 0.5 to 1.2%, titanium (Ti): 0.01 to 0.3%, carbon (C): 0.005 to 0.015%, cerium (Ce): 0.1 ~0.3%, containing residual aluminum (Al) and other unavoidable impurities,

The impurities are selected from copper (Cu): 0.08% or less, manganese (Mn): 0.05% or less, magnesium (Mg): 0.05% or less, chromium (Cr): 0.1% or less, and zinc (Zn): 0.1% or less. contains one or more species, and

An aluminum alloy for casting having excellent thermal conductivity that satisfies each of the following relational expressions 1-4 is provided.

[Relationship 1]

4.7% by weight ≤ Si+Fe ≤ 7.5% by weight

[Relationship 2]

2.9 ≤ Si/Fe ≤ 14.0

[Relationship 3]

7.6≤[(Si+Fe)/(Ti+C+Ce)]≤ 17.2

[Relationship 4]

12.4≤ [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] ≤112.0

In the present invention, it is preferable that the Si+Fe value defined by the relational expression 1 is 4.9 to 5.6% by weight.

In addition, it is preferable that the Si / Fe content ratio defined by the relational expression 2 is 4.4 to 8.3.

In addition, it is more preferable that the (Si+Fe)/(Ti+C+Ce) content ratio defined by the relational expression 3 is 15.02 to 17.2.

In addition, the casting aluminum alloy of the present invention, in weight%, silicon (Si): 4.0 to 5.0%, iron (Fe): 0.6 to 0.9%, It is preferable to include titanium (Ti): 0.01 to 0.025%, carbon (C): 0.01 to 0.015%, and cerium (Ce): 0.2 to 0.3%.

In addition, the impurities are, by weight, copper (Cu): 0.005% or less, manganese (Mn): 0.005% or less, magnesium (Mg): 0.005% or less, chromium (Cr): 0.015% or less, and zinc (Zn): 0.02% or less It is preferable to include one or more selected from % or less.

In addition, the [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] content ratio defined by the relational expression 4 preferably has a range of 98.0 to 112.0.

The aluminum alloy of the present invention may have a yield strength of 80 to 140 N/mm2 or more, and a thermal conductivity of 170 to 200 W/mK.

Another aspect of the present invention is

a step of melting an aluminum alloy having the above components;

a step of obtaining a cast product by casting using the molten aluminum alloy molten metal; and

It relates to a method for manufacturing an aluminum cast alloy having excellent thermal conductivity, including a step of annealing the cast product at a temperature range of 320 to 350 ° C. for 1 to 3 hours and then air cooling.

The process of manufacturing the aluminum alloy molten metal,

A first step of producing molten Al by charging aluminum into a melting furnace and then heating it to a temperature equal to or higher than its melting point; A second step of injecting Si and Fe into molten metal at a temperature of 740 to 770 ° C; A third step of injecting the Ce master alloy into the molten metal at a temperature of 740 to 770 ° C; A fourth step of raising the temperature again and injecting the 50% C master alloy into the molten metal at 790 to 820 ° C; A fifth step of injecting Ti into molten metal at 730 to 770 ° C; A sixth step of removing impurities such as gas and oxides in the molten metal by blowing Ar (argon) gas at a temperature of 740 to 760 ° C for 15 to 20 minutes; and a seventh step of tapping the molten metal at a temperature of 680 to 700°C.

The casting may be a die casting casting.

The present invention configured as described above can effectively provide an aluminum alloy for casting capable of achieving high thermal conductivity while ensuring high fluidity and enabling thin plate casting. Specifically, the present invention can effectively provide an aluminum alloy material with a yield strength of 80 to 140 N/mm2 (based on ASTM E8/E8M-16a), a thermal conductivity of 170 to 200 W/mK [based on the laser flash method], and castable up to 0.3T in sheet molding. There are advantages to being able to

Figure 1 (a-b) is a product picture showing the degree of casting defects for the cast product manufactured according to an embodiment of the present invention, Figure 1 (a) is a cast product (invention example 4) of the present invention, and Figure 1 (b) is a photograph showing a cast product (Comparative Example 1) out of the conditions of the present invention.

Hereinafter, the present invention will be described.

Casting aluminum alloy having excellent thermal conductivity according to one aspect of the present invention, in weight%, silicon (Si): 3.5 ~ 7.0%, iron (Fe): 0.5 ~ 1.2%, titanium (Ti): 0.01 ~ 0.3%, Carbon (C): 0.005 to 0.015%, cerium (Ce): 0.1 to 0.3%, residual aluminum (Al) and other unavoidable impurities, including copper (Cu): 0.08% or less, manganese (Mn) : 0.05% or less, magnesium (Mg): 0.05% or less, chromium (Cr): 0.1% or less, and zinc (Zn): 0.1% or less, and satisfies each of the following relational expressions 1-4.

The present invention properly controls the content and content ratio of Si, which can improve the castability of base metal aluminum, and Fe, which can be dissolved in an aluminum matrix to obtain a solid solution strengthening effect. In addition, it is characterized in that the ratio of the total content of the impurity elements to the total content of the Si and Fe elements is controlled within a certain range.

Accordingly, it is confirmed that it is possible to provide an aluminum alloy having excellent castability and, furthermore, excellent yield strength and thermal conductivity characteristics of manufactured cast products, and the present invention is proposed.

Hereinafter, the reasons for adding and limiting the content of each alloying element will be described, and here, "%" means weight %.

Silicon (Si): 3.5 to 7.0%

In the present invention, silicon (Si) is an element that can be added as an alloying element to base aluminum to improve castability and increase tensile strength according to the solid solution strengthening effect. In the present invention, it is preferable to limit the silicon (Si) content to the range of 3.5 to 7.0%. If the silicon content is less than 3.5%, the castability of the alloy is lowered, and when forming the product by die casting, some unmolded parts are generated, which can greatly damage the soundness of the cast product. If the silicon content exceeds 7.0%, heat conduction This is because the conductivity is lowered and the thermal conductivity of 170 W/mK or more targeted in the present invention cannot be obtained. More preferably, the amount of silicon added is controlled in the range of 4.0 to 5.0%.

Iron (Fe): 0.5 to 1.2%

In the present invention, since iron (Fe) has a very low solid solubility of 0.052% by weight in aluminum at room temperature, it is mostly crystallized as an intermetallic compound such as AlFe after casting, so it is added to aluminum to minimize the decrease in thermal conductivity of aluminum and increase strength. It is an alloying element that can increase and at the same time reduce mold seizure when forming an aluminum alloy product by die casting. In the present invention, it is preferable to limit the iron (Fe) content to the range of 0.5 to 1.2%. If the iron content is less than 0.5%, the effect of preventing mold sticking is lowered, and when the product is molded by die casting, the product sticking phenomenon occurs in some mold parts and the mechanical strength is not sufficient, and the iron content is 1.2% This is because if it exceeds , the Fe-enriched phase (Fe-rich phase) is excessively crystallized in the alloy, thereby degrading the castability of the alloy. More preferably, the iron content is controlled in the range of 0.6 to 0.9%.

・Titanium (Ti): 0.01~0.3%

In the present invention, titanium (Ti) is an alloying element capable of obtaining crystal grain refinement and crack prevention effects of cast materials. In addition, since aluminum particles are miniaturized, thermal conduction potential movement is facilitated, and the structure is miniaturized, so thin molding is facilitated. In other words, Ti forms a precipitate of Al (2+, 3+) on Ti of 40 nanomicrons or less, which refines aluminum particles to facilitate the movement of heat transfer potential, improve the casting structure, and enable thin plate forming. It is a useful ingredient that makes In the present invention, it is preferable to control the Ti content in the range of 0.01 to 0.3%. If the Ti content is less than 0.01%, there is little effect of improving casting performance and thermal conductivity through the aluminum particle refinement effect, and if the Ti content exceeds 0.3%, there is a problem of thermal conductivity deterioration.

More preferably, the Ti content is controlled in the range of 0.01 to 0.025%.

·Carbon (C): 0.005~0.015%

In the present invention, carbon (C) serves as a solidification nucleus so that the alloy structure can be uniformly cooled when the molten metal moves into the mold and starts to cool, thereby increasing the mechanical strength, electrical conductivity and It is an element that contributes to the improvement of thermal conductivity. In the present invention, it is preferable to control the amount of carbon added in the range of 0.005 to 0.015%. If the content is less than 0.005%, there is no effect of improving thermal conductivity and mechanical strength, and if it exceeds 0.015%, the thermal conductivity is rather deteriorated. have. More preferably, the amount of carbon added is controlled in the range of 0.01 to 0.015%.

Cerium (Ce): 0.1~0.3%

In the present invention, cerium (Ce) is a type of rare earth La-based, and is added for the purpose of increasing thermal conductivity. When cerium (Ce) is added, impurities are removed, electrical conductivity increases, and a heat transfer distance can be shortened by acting as a bridge between elements through which heat is transferred. Therefore, in the present invention, cerium (Ce) is an effective component for increasing electrical conductivity and improving thermal conductivity. In the present invention, it is preferable to control the addition amount of the cerium (Ce) in the range of 0.1 to 0.3%. If the amount of cerium (Ce) added is less than 0.1%, the thermal conductivity improvement effect does not appear, and if it exceeds 0.3%, there is a problem in that the thermal conductivity is lowered. More preferably, the amount of cerium (Ce) added is within the range of 0.2 to 0.3%.

·Si+Fe

[Relationship 1]

4.7% by weight ≤ Si+Fe ≤ 7.5% by weight

In the present invention, it is preferable to limit the sum of Si and Fe alloy elements defined by the relational expression 1 to 4.7% by weight or more and 7.5% by weight or less. If the sum of the Si and Fe element contents is less than 4.7% by weight, the yield strength does not meet the standard and the workability is lowered, and the gate, runner, and overflow, which are the passages of molten metal in the casting product, are not easily separated. , and if it exceeds 7.5% by weight, the thermal conductivity may not meet the target standard.

More preferably, the Si + Fe value defined by the relational expression 1 is managed in the range of 4.9 to 5.6% by weight.

·Si/Fe

[Relationship 2]

2.9 ≤ Si/Fe ≤ 14.0

In the present invention, it is also preferable to manage the Si / Fe content ratio defined by the relational expression 2 in the range of 2.9 or more and 14.0 or less. If the Si / Fe ratio is less than 2.9, there is a problem of fluidity deterioration due to an increase in Fe content, and if it exceeds 14.0, there may be a problem that continuous operation is difficult because the molten metal is stuck to the mold.

More preferably, the Si / Fe content ratio defined by the relational expression 2 is managed in the range of 4.4 to 8.3.

・(Si+Fe)/(Ti+C+Ce)

[Relationship 3]

7.6≤[(Si+Fe)/(Ti+C+Ce)]≤ 17.2

In the present invention, it is also preferable to manage the (Si+Fe)/(Ti+C+Ce) content ratio defined by the relational expression 3 in the range of 7.6 or more and 17.2 or less. If the content ratio is less than 7.6, there is a problem that the thermal conductivity and mechanical strength required in the present invention, the cleanliness of the molten metal for castability, the effect of refining aluminum particles, the formation of a dense microstructure, and the securing of castability are lower than expected levels, and 17.2 If it is exceeded, there may be a problem in that the thermal conductivity is lowered.

More preferably, the (Si+Fe)/(Ti+C+Ce) content ratio defined by the relational expression 3 is controlled in the range of 15.02 to 17.2.

In addition, the aluminum alloy of the present invention contains base aluminum and unavoidable impurities as residual components. In the present invention, since the control of the content of impurities has a great effect on the heat dissipation characteristics of a cast product manufactured using an aluminum alloy, it is preferable to reduce the content as much as possible.

In the aluminum alloy of the present invention, the impurities are, by weight, copper (Cu): 0.08% or less, manganese (Mn): 0.05% or less, magnesium (Mg): 0.05% or less, chromium (Cr): 0.1% or less and zinc (Zn): 0.1% or less.

In the present invention, the total amount of the impurities is preferably limited to 0.20% by weight or less, more preferably 0.10% by weight or less, and most preferably 0.05% by weight or less. Hereinafter, the addition of the content of each impurity and the reason for its limitation will be described.

·Copper (Cu): 0.08% or less

In the present invention, copper improves cutting workability but lowers corrosion resistance, and when added, it forms a phase with Si and Fe to hinder the movement of dislocations, so it is preferable to manage its content to 0.08% or less, more preferably to 0.005% or less. is to manage

Manganese (Mn): 0.05% or less

Manganese, as a transition element, increases the recrystallization temperature and promotes the formation of fibrous tissue in hot working to suppress crystal grain growth, so the content is preferably managed to 0.05% or less, more preferably 0.005% or less.

Magnesium (Mg): 0.05% or less

Magnesium is an element that generally combines with Al to form an Al ₂ Mg ₂ phase to increase strength, ductility and corrosion resistance. However, if its content is excessive, the thermal conductivity is reduced by more than 10 W / mK, so it is desirable to manage it in the range of 0.05% or less , More preferably, it is to manage to 0.005% or less.

Chromium (Cr): 0.1% or less

Chromium prevents stress corrosion cracking and improves corrosion resistance, but lowers thermal conductivity, so it is preferable to manage the content to 0.1% or less, more preferably, to manage to 0.015% or less.

Zinc (Zn): 0.1% or less

Zinc increases the yield strength but lowers the thermal conductivity, so it is preferable to manage the content to 0.1% or less, more preferably, to manage to 0.02% or less.

・[(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)]

[Relationship 4]

12.4≤ [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] ≤ 112.0

In the present invention, it is preferable to manage the [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] value defined by the relational expression 4 in the range of 12.4 or more and 112.0 or less. If the value is less than 12.4, there is a problem of thermal conductivity deterioration due to the impurity content, and if it exceeds 112.0, the thermal conductivity does not increase any more, and cost, manufacturing process and mass productivity are inefficient due to excessively selecting ultra-high purity materials. there is a problem

Furthermore, in the present invention, it is more preferable that the [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] value defined by the relational expression 4 satisfies the range of 98.0 to 112.0.

Next, the manufacturing method of the above-described aluminum alloy cast product having excellent thermal conductivity of the present invention will be described.

The aluminum casting method of the present invention includes a step of melting the aluminum alloy formed as described above; a step of obtaining a cast product by casting using the molten aluminum alloy molten metal; and air-cooling after annealing the cast product at a temperature range of 320 to 350° C. for 1 to 3 hours.

In the present invention, first, an aluminum alloy molten metal is manufactured.

Specifically, the process of manufacturing the aluminum alloy molten metal includes a first step of manufacturing an Al molten metal by charging aluminum into a melting furnace and then heating it to a temperature equal to or higher than its melting point; A second step of injecting Si and Fe into molten metal at a temperature of 740 to 770 ° C; A third step of injecting the Ce master alloy into the molten metal at a temperature of 740 to 770 ° C; A fourth step of raising the temperature again and injecting the 50% C master alloy into the molten metal at 790 to 820 ° C; A fifth step of injecting Ti into molten metal at 730 to 770 ° C; A sixth step of removing impurities such as gas and oxides in the molten metal by blowing Ar (argon) gas at a temperature of 740 to 760 ° C for 15 to 20 minutes; and a seventh step of tapping the molten metal at a temperature of 680 to 700°C. The first process is a process for completing the alloy within a short time at an appropriate temperature to reduce oxides in the molten metal, the second process is a process for controlling the set temperature to inject the Ce master alloy, a high specific gravity alloy, and the third process The process is a process of controlling the temperature for introducing C to smoothly stir the molten metal, the fourth process is a process of controlling the temperature for smoothly stirring Ti, and the fifth process is a process of controlling the temperature using Ar gas It is a process of controlling the temperature of the molten metal in consideration of the temperature drop of the molten metal during the degassing process for about 15 minutes.

Subsequently, in the present invention, an aluminum alloy cast product is manufactured by casting using the prepared aluminum molten metal. The present invention is not limited to the above casting method, and gravity casting, squeeze casting, die casting casting, mold high-speed casting, semi-solid casting, etc. may be used, and preferably die casting casting is used.

And in the present invention, a final cast product can be obtained by annealing the aluminum alloy cast product. This annealing process is performed for the purpose of improving thermal conductivity and mechanical properties, and in the present invention, it is preferable to control the annealing temperature range to 320 ~ 350 ℃. If the temperature is less than 320 ° C, the annealing time must be long, so the cost increases, and if the temperature exceeds 350 ° C, there is a problem that blisters are generated in the cast product.

Preferably, the annealing time is controlled to 1 to 3 hours.

The aluminum alloy cast product of the present invention manufactured through the above-described manufacturing process may have a yield strength of 80 to 100 N/mm2 and a thermal conductivity of 170 to 200 W/mK.

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

(Example)

After preparing a raw material of an aluminum alloy satisfying the composition components shown in Table 1 below, it was charged into an electric resistance melting furnace to melt the raw material in the air to prepare molten metal, respectively. Thereafter, they were cast at high pressure by die casting to prepare aluminum alloy cast pieces, respectively. Meanwhile, Toshiba 250 ton and Ube 3550 ton facilities were used for this die casting.

With respect to the cast steel prepared as described above, yield strength and thermal conductivity were measured and shown in Table 2 below. In addition, in order to confirm the castability of the cast steel, casting defects were visually evaluated for 200 castings (approximately 3 minutes per casting cycle product 1EA).

Meanwhile, in this experiment, the yield strength was measured based on the ASTM E8/E8M-16a standard. And the thermal conductivity was measured based on the laser flash method and NETZSCH LFA Analysis (KS L 1604), specifically, with a diameter of 12.5 to 12.8 mm. and a specimen having a thickness of 1 to 3 mm was prepared and measured according to the laser flash method and NETZSCH LFA Analysis (KS L 1604) under a temperature of 25 ° C and a humidity of 15% R.H. In addition, as a result of observing casting defects for cast products, the castability of the cast steel was evaluated as "high" when the defect rate was 1% or less, "medium" when the defect rate was 5% or less, and "low" when the defect rate was 10% or less. did

division Alloy composition (%) Si Fe Ti C Ce Si+Fe Si/Fe A* B* C* Invention example 1 4 0.9 0.3 0.015 0.3 4.9 4.4 8.0 0.38 12.9 Invention example 2 4.5 1.1 0.025 0.00125 0.3 5.6 4.1 17.2 0.32 17.5 Invention example 3 4.5 0.6 0.2 0.01 0.25 5.1 7.5 11.1 0.05 102.0 Invention example 4 4.7 0.6 0.025 0.00125 0.3 5.3 7.8 16.2 0.05 106.0 Invention example 5 5.0 0.6 0.025 0.00125 0.3 5.6 8.3 17.2 0.05 112.0 Example 6 6.8 0.7 0.3 0.015 0.3 7.5 9.7 12.2 0.38 19.7 Example 7 4.5 1.2 0.035 0.00175 0.3 5.7 3.8 16.9 0.32 17.8 Invention Example 8 5.1 0.5 0.2 0.01 0.25 5.6 10.2 12.2 0.05 112.0 Comparative Example 1 3.5 1.2 0.5 0.8 0.6 4.7 2.9 2.5 0.38 7.7 Comparative Example 2 5.5 1.1 0.4 0.04 0.7 6.6 5.0 5.8 0.32 15.6 Comparative Example 3 6.5 1.2 0.1 0.05 0.1 7.7 5.4 30.8 0.105 51.6 Comparative Example 4 3.5 1.2 0.25 0.0125 0.3 4.7 2.9 8.4 0.57 5.1 Comparative Example 5 5.5 1.0 0.3 0.015 0.3 6.5 5.5 10.6 0.8 6.9 Comparative Example 6 6.5 0.8 0.2 0.01 0.25 7.3 8.1 15.9 1.04 7.8 Comparative Example 7 7.0 0.3 0.25 0.0125 0.3 7.3 23.3 13.0 0.32 72.9 Comparative Example 8 3.0 1.5 0.2 0.01 0.25 4.5 2.0 9.8 0.105 19.0

*In Table 1, the remaining component is Al, A* is the content ratio of (Si+Fe)/(Ti+C+Ce), and B* is the sum of the content of impurity elements (Cu+Mn+Mg+Cr+Zn) , and C* represents the [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] content ratio.

Table 2 below shows the contents of individual impurity elements constituting the impurities in Table 1 above.

division Impurity composition (%) Cu Mn Mg Cr Zn Invention example 1 0.08 0.05 0.05 0.1 0.1 Invention example 2 0.07 0.04 0.03 0.08 0.1 Invention example 3 0.005 0.005 0.005 0.015 0.02 Invention example 4 0.005 0.005 0.005 0.015 0.02 Invention example 5 0.005 0.005 0.005 0.015 0.02 Example 6 0.08 0.05 0.05 0.1 0.1 Example 7 0.07 0.04 0.03 0.08 0.1 Invention Example 8 0.005 0.005 0.005 0.015 0.02 Comparative Example 1 0.08 0.05 0.05 0.1 0.1 Comparative Example 2 0.07 0.04 0.03 0.08 0.1 Comparative Example 3 0.06 0.005 0.005 0.015 0.02 Comparative Example 4 0.1 0.05 0.2 0.02 0.2 Comparative Example 5 0.1 0.07 0.4 0.03 0.2 Comparative Example 6 0.1 0.09 0.6 0.05 0.2 Comparative Example 7 0.07 0.04 0.03 0.08 0.1 Comparative Example 8 0.06 0.005 0.005 0.015 0.02

Main piece No. Yield strength (N/mm2) Thermal conductivity (W/mK) castability note One 82 177 award Invention example 1 2 90 185 award Invention example 2 3 86 187 award Invention example 3 4 88 196 award Invention example 4 5 92 198 award Invention example 5 6 121 171 award Example 6 7 92 175 award Example 7 8 91 177 award Invention Example 8 9 98 135 under Comparative Example 1 10 78 142 middle Comparative Example 2 11 77 140 middle Comparative Example 3 12 65 128 under Comparative Example 4 13 95 120 middle Comparative Example 5 14 110 110 middle Comparative Example 6 15 118 165 middle Comparative Example 7 16 80 165 under Comparative Example 8

As shown in Table 1-3, it can be seen that all of Inventive Examples 1-8, in which the aluminum alloy composition ratio satisfies the range of the present invention, not only have excellent castability, but also have excellent yield strength and thermal conductivity. In particular, (Si+Fe)/(Cu+Mn+Mg+Cr+Zn) content ratio of 98.0 to 112.0, (Si+Fe)/(Ti+C+Ce) content ratio of 15.02 to 17.2 and Si/Fe ratio of 4.4 to It can be seen that Inventive Examples 4-5 satisfying 8.3 show the most excellent thermal conductivity characteristics compared to Inventive Examples 1-3 and Inventive Examples 6-8 that do not.

In contrast, Comparative Example 1 is a case where the (Si + Fe) / (Ti + C + Ce) content ratio and (Si + Fe) / (Cu + Mn + Mg + Cr + Zn) content ratio are outside the scope of the present invention. , In particular, the thermal conductivity of cast steel was poor.

In Comparative Example 2-3, the (Si+Fe)/(Ti+C+Ce) content ratio was outside the scope of the present invention, and the yield strength and thermal conductivity of the cast steel were very poor.

In Comparative Examples 4-5, the (Si+Fe)/(Cu+Mn+Mg+Cr+Zn) content ratio is outside the scope of the present invention, and it is observed that the thermal conductivity is significantly lowered, so that the effect of impurities on the thermal conductivity can be clearly identified.

Furthermore, in Comparative Examples 7 and 8, the Si/Fe content ratio was out of the range of the present invention, and the thermal conductivity, castability, and mechanical properties were deteriorated.

On the other hand, Figure 1 (a-b) is a product picture showing the degree of casting defects for the cast product manufactured according to an embodiment of the present invention, Figure 1 (a) is a cast product (invention example 4) of the present invention, and Figure 1 (b) ) is a photograph showing a cast product (Comparative Example 1) out of the conditions of the present invention.

As described above, the detailed description of the present invention has been described with respect to the preferred embodiments of the present invention, but those skilled in the art to which the present invention belongs can make various modifications without departing from the scope of the present invention. Of course this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims described later, but also those equivalent thereto.

Claims (17)

In weight percent, silicon (Si): 3.5 to 7.0%, iron (Fe): 0.5 to 1.2%, titanium (Ti): 0.01 to 0.3%, carbon (C): 0.005 to 0.015%, cerium (Ce): 0.1 ~0.3%, containing residual aluminum (Al) and other unavoidable impurities,
The impurities are selected from copper (Cu): 0.08% or less, manganese (Mn): 0.05% or less, magnesium (Mg): 0.05% or less, chromium (Cr): 0.1% or less, and zinc (Zn): 0.1% or less. containing one or more species in the range of 0.05 to 0.38%, and
An aluminum alloy for casting having excellent thermal conductivity that satisfies the following relational expressions 1-4, respectively.
[Relationship 1]
4.7% by weight ≤ Si+Fe ≤ 7.5% by weight
[Relationship 2]
2.9 ≤ Si/Fe ≤ 14.0
[Relationship 3]
7.6≤[(Si+Fe)/(Ti+C+Ce)]≤ 17.2
[Relationship 4]
12.4≤ [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] ≤112.0
The cast aluminum alloy having excellent thermal conductivity according to claim 1, wherein the Si+Fe value defined by the relational expression 1 is 4.9 to 5.6% by weight.
The cast aluminum alloy having excellent thermal conductivity according to claim 1, wherein the Si/Fe content ratio defined by the relational expression 2 is 4.4 to 8.3.
The casting aluminum alloy having excellent thermal conductivity according to claim 1, wherein the (Si+Fe)/(Ti+C+Ce) content ratio defined by the relational expression 3 is 15.02 to 17.2.
The method of claim 1, wherein the casting aluminum alloy, in weight%, silicon (Si): 4.0 ~ 5.0%, iron (Fe): 0.6 ~ 0.9%, Titanium (Ti): 0.01 ~ 0.025%, carbon (C): 0.01 ~ 0.015%, and cerium (Ce): 0.2 ~ 0.3%, characterized in that it comprises an aluminum alloy for casting with excellent thermal conductivity.
The method of claim 1, wherein the impurities are, by weight%, copper (Cu): 0.005% or less, manganese (Mn): 0.005% or less, magnesium (Mg): 0.005% or less, chromium (Cr): 0.015% or less, and zinc (Zn): An aluminum alloy for casting with excellent thermal conductivity, characterized in that it contains at least one selected from among 0.02% or less.
The casting according to claim 1, wherein the [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] content ratio defined by the relational expression 4 has a range of 98.0 to 112.0. aluminum alloy.
The aluminum alloy for casting according to claim 1, wherein the aluminum alloy has a yield strength of 80 to 140 N/mm2 or more and a thermal conductivity of 170 to 200 W/mK.
In weight percent, silicon (Si): 3.5 to 7.0%, iron (Fe): 0.5 to 1.2%, titanium (Ti): 0.01 to 0.3%, carbon (C): 0.005 to 0.015%, cerium (Ce): 0.1 ~0.3%, containing residual aluminum (Al) and other unavoidable impurities; The impurities are selected from copper (Cu): 0.08% or less, manganese (Mn): 0.05% or less, magnesium (Mg): 0.05% or less, chromium (Cr): 0.1% or less, and zinc (Zn): 0.1% or less. containing one or more species in the range of 0.05 to 0.38%; and melting an aluminum alloy that satisfies each of the following relational expressions 1-4;
a step of obtaining a cast product by casting using the molten aluminum alloy molten metal; and
An aluminum cast alloy manufacturing method having excellent thermal conductivity, including a step of air-cooling the cast product after annealing for 1 to 3 hours in a temperature range of 320 to 350 ° C.

[Relationship 1]
4.7% by weight ≤ Si+Fe ≤ 7.5% by weight
[Relationship 2]
2.9 ≤ Si/Fe ≤ 14.0
[Relationship 3]
7.6≤[(Si+Fe)/(Ti+C+Ce)]≤ 17.2
[Relationship 4]
12.4≤ [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] ≤112.0
10. The method of claim 9, wherein the Si+Fe value defined by the relational expression 1 is 4.9 to 5.6% by weight.
The method of claim 9, wherein the Si/Fe content ratio defined by the relational expression 2 is 4.4 to 8.3.
The method of claim 9, wherein the (Si+Fe)/(Ti+C+Ce) content ratio defined by the relational expression 3 is 15.02 to 17.2.
10. The method of claim 9, wherein the casting aluminum alloy, in weight%, silicon (Si): 4.0 ~ 5.0%, iron (Fe): 0.6 ~ 0.9%, Titanium (Ti): 0.01 ~ 0.025% , carbon (C): 0.01 ~ 0.015% and cerium (Ce): aluminum casting alloy manufacturing method with excellent thermal conductivity, characterized in that it comprises 0.2 ~ 0.3%.
10. The method of claim 9, wherein the impurities are, by weight, copper (Cu): 0.005% or less, manganese (Mn): 0.005% or less, magnesium (Mg): 0.005% or less, chromium (Cr): 0.015% or less, and zinc (Zn): A method for producing an aluminum casting alloy having excellent thermal conductivity, characterized in that it contains at least one selected from among 0.02% or less.
The aluminum casting having excellent thermal conductivity according to claim 9, wherein the content ratio of [(Si+Fe)/(Cu+Mn+Mg+Cr+Zn)] defined by the relational expression 4 ranges from 98.0 to 112.0. alloy manufacturing method.
The method of claim 9, wherein the process of manufacturing the aluminum alloy molten metal,
A first step of producing molten Al by charging aluminum into a melting furnace and then heating it to a temperature equal to or higher than its melting point; A second step of injecting Si and Fe into molten metal at a temperature of 740 to 770 ° C; A third step of injecting the Ce master alloy into the molten metal at a temperature of 740 to 770 ° C; A fourth step of raising the temperature again and injecting the 50% C master alloy into the molten metal at 790 to 820 ° C; A fifth step of injecting Ti into molten metal at 730 to 770 ° C; A sixth step of removing impurities such as gas and oxides in the molten metal by blowing Ar (argon) gas at a temperature of 740 to 760 ° C for 15 to 20 minutes; And a seventh step of tapping the molten metal at a temperature of 680 ~ 700 ℃; aluminum casting alloy manufacturing method with excellent thermal conductivity, characterized in that it comprises a.
10. The method of claim 9, wherein the casting is a die casting casting.

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