Non-heat-treated high-elongation aluminum alloy and aluminum alloy casting excluding copper

Abstract

The present invention provides an aluminum alloy and an aluminum alloy casting that, while excluding copper, can ensure appropriate strength and have excellent corrosion resistance and elongation. The aluminum alloy according to the present invention comprises 2.0-5.0 wt% of silicon (Si), 0.02-0.45 wt% of manganese (Mn), 0.00-0.50 wt% of iron (Fe), 6.00-9.00 wt% of magnesium (Mg), 0.10 wt% or less of chromium (Cr), 0.10 wt% or less of nickel (Ni), 0.10 wt% or less of vanadium (V), 0.50 wt% or less of titanium (Ti), 0.50 wt% or less of zinc (Zn), and the balance of aluminum (Al) and production-derived substances.

Description

Copper-free, high-elongation non-heat-treatable aluminum alloys and aluminum alloy castings

[0001] The present invention relates to aluminum alloys and aluminum alloy castings, and more specifically, to aluminum alloys and aluminum alloy castings that can obtain appropriate strength and high elongation while undergoing non-heat treatment without including copper as a composition.

[0002] Aluminum alloys are widely used as industrial materials in various fields, including vehicles, civil engineering, construction, shipbuilding, chemicals, aerospace, and food.

[0003] Generally, copper is used as a major strengthening element in Al-Cu and Al-Zn-Mg-Cu alloys. In other words, aluminum alloys containing copper exhibit increased strength and hardness; specifically, they can increase fatigue strength, improve wear resistance, and maintain a certain level of strength even at high temperatures.

[0004] However, in the case of copper-free aluminum alloys, corrosion resistance is reduced, making them particularly susceptible to stress corrosion cracking; elongation decreases, leading to increased brittleness and reduced weldability; and a heat treatment process is required to ensure strength.

[0005] On the other hand, when aluminum alloys are reinforced with Mg, Zn, Si, etc., without including copper, there are advantages such as excellent corrosion resistance, increased elongation and toughness, and improved weldability; however, there are problems such as reduced strength and hardness, which weakens the alloy particularly in high-temperature environments, low fatigue strength making it vulnerable to repeated loading, and difficulty in maintaining strength at high temperatures.

[0006] Therefore, there is a need for an aluminum alloy that does not contain copper but can not only provide excellent corrosion resistance and elongation but also ensure adequate strength.

[0007] Registered Patent No. 10-1052517 relates to an aluminum alloy casting, specifically an aluminum alloy casting that does not require heat treatment. However, there is a problem in that its mechanical strength is insufficient to support a large load.

[0008] Registered Patent No. 10-1955993 relates to a high-strength aluminum alloy and a high-strength aluminum alloy casting, and shows an aluminum alloy with improved strength by including copper.

[0009] The present invention provides an aluminum alloy and an aluminum alloy casting that do not contain copper, yet possess excellent corrosion resistance and elongation, as well as secure appropriate strength.

[0010] The present invention provides an aluminum alloy and an aluminum alloy casting that not only do not contain copper but also possess excellent corrosion resistance and elongation without performing heat treatment during the manufacturing process, as well as secure appropriate strength.

[0011] The present invention provides an aluminum alloy and an aluminum alloy casting that contain appropriate amounts of silicon (Si) and magnesium (Mg) without including copper or performing heat treatment, and can secure not only excellent corrosion resistance and elongation but also appropriate strength.

[0012] The present invention provides an aluminum alloy and an aluminum alloy casting that can secure appropriate strength as well as excellent corrosion resistance and elongation by including chromium (Cr) and nickel (Ni) along with appropriate amounts of silicon (Si), manganese (Mn), iron (Fe), magnesium (Mg), vanadium (V), titanium (Ti), zinc (Zn), and aluminum (Al) without including copper or performing heat treatment.

[0013] The copper-free, high-elongation non-heat-treatable aluminum alloy of the present invention for achieving the above objective is characterized by comprising 2.0 to 5.0 wt% silicon (Si), 0.02 to 0.45 wt% manganese (Mn), 0.00 to 0.50 wt% iron (Fe), 6.00 to 9.00 wt% magnesium (Mg), 0.10 wt% or less chromium (Cr), 0.10 wt% or less nickel (Ni), 0.50 wt% or less vanadium (V), 0.50 wt% or less titanium (Ti), 0.50 wt% or less zinc (Zn), and the remainder aluminum (Al) and production-inducing substances.

[0014] A more preferred copper-free, high-elongation non-heat-treatable aluminum alloy of the present invention for achieving the above objective is characterized by comprising 2.0 to 3.80 wt% silicon (Si), 0.01 to 0.05 wt% manganese (Mn), 0.01 to 0.25 wt% iron (Fe), 6.50 to 9.00 wt% magnesium (Mg), 0.01 to 0.09 wt% chromium (Cr), 0.001 to 0.09 wt% nickel (Ni), 0.01 to 0.50 wt% vanadium (V), 0.01 to 0.50 wt% titanium (Ti), 0.01 to 0.20 wt% zinc (Zn), and the remainder being aluminum (Al) and a production-inducing substance.

[0015] The aluminum alloy of the present invention may further include other components consisting of lead, phosphorus, and carbon, each up to 0.05 weight%.

[0016] The above aluminum alloy is produced in the form of an ingot by including the steps of: producing a first master alloy comprising aluminum (Al), nickel (Ni), manganese (Mn), iron (Fe), chromium (Cr), and titanium (Ti); sequentially melting the first master alloy and a second master alloy comprising aluminum (Al) and vanadium (V) in a melting furnace; and, once the melting of the first master alloy and the second master alloy is completed, charging magnesium (Mg) and zinc (Zn) into the melting furnace to melt them.

[0017] The above-mentioned first master alloy is produced by weighing each element according to the weight percentage of the alloy on an electronic balance, placing a portion of aluminum into an electric furnace and heating it, and once the aluminum is melted, first charging and melting nickel (Ni), after the nickel (Ni) is melted, charging and melting manganese (Mn), after the manganese (Mn) is melted, charging and melting iron (Fe) and chromium (Cr), and finally charging and melting titanium (Ti), and once the titanium (Ti) is melted, additional aluminum is charged.

[0018] The melting of the first master alloy is carried out by charging pure aluminum (AL) into the melting furnace and melting it, and after the pure aluminum (AL) is melted, charging silicon (Si) and melting it, and after the silicon (Si) is melted, charging the first master alloy and melting it.

[0019] The melting of the second master alloy is characterized by melting the second master alloy by charging it into the melting furnace while maintaining a set temperature after the first master alloy has been melted.

[0020] In addition, the above aluminum alloy is characterized by having a tensile strength of 297.2 to 372.8 MPa, an elongation of 11.4% to 25.8%, a compressive strength of 478.5 MPa to 534.5 MPa, and a strain of 36.1% to 42.5%.

[0021] Another aspect of the present invention is characterized by a non-heat-treated aluminum alloy casting with high elongation that does not contain copper, manufactured by casting any one of the aluminum alloys described above.

[0022] According to the present invention, it is possible to obtain an aluminum alloy and an aluminum alloy casting that not only have excellent corrosion resistance and elongation but also secure appropriate strength without including copper in the aluminum alloy.

[0023] According to the present invention, by including appropriate amounts of silicon (Si) and magnesium (Mg) without including copper or performing heat treatment, it is possible to improve the corrosion resistance and elongation of the aluminum alloy, as well as secure appropriate strength.

[0024] According to the present invention, by including chromium (Cr) and nickel (Ni) along with appropriate amounts of silicon (Si), manganese (Mn), iron (Fe), magnesium (Mg), vanadium (V), titanium (Ti), zinc (Zn), and aluminum (Al) without including copper or performing heat treatment, it is possible to improve the corrosion resistance and elongation of the aluminum alloy as well as secure appropriate strength.

[0025] In addition, according to the present invention, since it is possible to obtain an aluminum alloy and an aluminum alloy casting that not only do not contain copper but also have excellent elongation and secure appropriate strength without heat treatment, the manufacturing process is simple and the manufacturing cost is low.

[0026] The method for manufacturing an aluminum alloy according to the present invention allows for the production of a first master alloy by selecting a portion of the materials (components) and melting them sequentially in order of lowest melting point, so that the work can be performed in a small melting furnace. Furthermore, when the first master alloy is remelted to finally produce an aluminum alloy, the materials are melted even at a low heat level, enabling efficient work and increasing the accuracy of the composition.

[0027] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0028] Figure 1 is an optical microscope image of the microstructure of an aluminum alloy according to the present invention.

[0029] Figure 2 is a scanning electron microscope image of an aluminum alloy according to the present invention, which is a photograph of a mapping performed to confirm the distribution of added elements.

[0030] Figure 3 is a graph of tensile strength and elongation that can be confirmed by comparing Alloy 1 and Alloy 2 of the aluminum alloy according to the present invention with Comparison 1 and 2.

[0031] Figure 4 is a graph of compressive strength and strain that can be confirmed by comparing alloy 4 and alloy 5 of the aluminum alloy according to the present invention with comparisons 1 and 2.

[0032] Figure 5 is a photograph comparing the surfaces of a general aluminum alloy and an aluminum alloy according to the present invention after a salt spray test.

[0033] Hereinafter, preferred embodiments of a copper-free, high-elongation non-heat-treatable aluminum alloy and an alloy casting according to the present invention will be described in detail.

[0034] The aluminum alloy according to the present invention is characterized by comprising 2.0 to 5.0 wt% silicon (Si), 0.02 to 0.45 wt% manganese (Mn), 0.00 to 0.50 wt% iron (Fe), 6.00 to 9.00 wt% magnesium (Mg), 0.10 wt% or less chromium (Cr), 0.10 wt% or less nickel (Ni), 0.50 wt% or less vanadium (V), 0.50 wt% or less titanium (Ti), 0.50 wt% or less zinc (Zn), the remainder being aluminum (Al) and a production-inducing substance.

[0035] In addition to the above additive elements, the aluminum alloy of the present invention may further include other components consisting of lead, phosphorus, and carbon, each in an amount of up to 0.05 weight%.

[0036] The above-mentioned additive element silicon (Si) contributes to the fluidity of the molten metal, thereby improving castability, and enhances strength by combining with aluminum or coexisting with Mg to form Mg2Si. When the silicon content is less than 2 wt%, tensile strength and compressive strength decrease; when the silicon content exceeds 5 wt%, tensile strength and compressive strength are satisfied, but elongation and strain are unsatisfactory. For this reason, the silicon content exhibits relatively satisfactory mechanical properties in the range of 2.0 wt% to 3.8 wt%, and the most desirable mechanical properties in the range of 2.0 wt% to 3.2 wt%.

[0037] The above-mentioned additive element manganese (Mn) has the effect of increasing strength through solid solution strengthening and the dispersion effect of fine precipitates, plays a role in preventing adverse effects caused by iron content, and has the effect of grain refinement. In order to perform these roles and exhibit appropriate effects, it is preferable to include manganese (Mn) in the range of 0.01 wt% to 0.05 wt%, and it is most preferable to include it in the range of 0.02 wt% to 0.05 wt%.

[0038] The above-mentioned additive element iron (Fe) has an effect of preventing sticking of the mold and influences the increase in strength through the grain refinement effect. If the iron (Fe) content exceeds 0.5 wt%, the strength range is good, but the elongation decreases, so it is not desirable to exceed 0.5 wt%. Accordingly, it is desirable to include iron (Fe) in the range of 0.01 wt% to 0.25 wt%, and in particular, it is most desirable to include it in the range of 0.02 wt% to 0.25 wt%.

[0039] The above-mentioned additive element magnesium (Mg) strengthens the alloy and increases its strength by forming dispersed precipitates in the form of fine metastable phase Mg2Si. However, excessive addition affects fluidity, and since it has a strong bonding affinity with oxygen, improper handling can cause oxide ingress; therefore, an appropriate amount must be added within the range defined above. In particular, Mg (magnesium) forms precipitates of silicon (Si) and Mg2Si, which affect the strength of the alloy. Specifically, it has been confirmed that the alloy has a desirable strength range within the range of 6.50 wt% to 9.00 wt%, and since exceeding 9.00 wt% results in a decrease in strength, the content must not exceed 9.00 wt%.

[0040] The above-mentioned additive element chromium (Cr) plays a role in refining the crystal grains and has the effect of improving strength. However, if contained in excessive amounts, coarse intermetallic compounds may be formed, which may lead to a decrease in machinability; therefore, an appropriate amount must be added within the range defined above. Accordingly, it is preferable to include chromium (Cr) in the range of 0.01 wt% to 0.09 wt%.

[0041] The above-mentioned additive element nickel (Ni) forms a compound to improve the strength of the alloy, and since ductility decreases if the Ni content exceeds 1%, an appropriate amount must be added within the range defined above. Accordingly, it is preferable to include nickel (Ni) in the range of 0.001 wt% to 0.09 wt%.

[0042] The above-mentioned additive element vanadium (V) has the effect of refining the crystal grains. In order to properly refine the crystal grains, it is preferable to include nickel (Ni) in the range of 0.01 wt% to 0.50 wt%, and most preferable to include it in the range of 0.01 wt% to 0.08 wt%.

[0043] The above-mentioned additive element titanium (Ti) refines the grain size, thereby improving castability and mechanical properties. Since excessive content causes a decrease in fluidity, an appropriate amount must be added within the range defined above. When the content of Ti (titanium) in the aluminum alloy is 0.5 wt% or more, tensile strength, elongation, yield strength, and strain decrease. Therefore, in order to refine the grain size and improve castability and mechanical properties without reducing the fluidity of the aluminum alloy, it is desirable to include titanium (Ti) in the range of 0.01 wt% to 0.50 wt%, and it is most desirable to include it in the range of 0.01 wt% to 0.15 wt%.

[0044] The above-mentioned additive element zinc (Zn) coexists with magnesium (Mg) to improve mechanical properties. Since solidification shrinkage increases when the content is high, an appropriate amount must be added within the range defined above. It is preferable to include zinc (Zn) in the range of 0.01 wt% to 0.20 wt%.

[0045] Next, a method for manufacturing an aluminum alloy according to the present invention will be described.

[0046] First, the first master alloy is produced through the following process.

[0047] 1) Each element is weighed on an electronic balance according to the weight percentage of the alloy.

[0048] 2) Put some aluminum into a small electric furnace and heat it.

[0049] 3) Once the aluminum is completely melted, nickel (Ni) is charged first. Since nickel (Ni) melts with aluminum at a temperature of about 700°C when the concentration is about 6% by weight or less, it is charged first and melted.

[0050] 4) Once nickel (Ni) is completely dissolved, manganese (Mn), which has a relatively low melting point among the added elements, is added and dissolved.

[0051] 5) Once manganese (Mn) is completely dissolved, iron (Fe) and chromium (Cr) are charged together and dissolved because they are solid solutions.

[0052] 6) Once the previously charged materials are completely melted, titanium (Ti) is finally charged and melted.

[0053] 7) When the titanium (Ti) is completely melted, additional aluminum is added to increase the weight percentage of aluminum so that the melting point is lowered when remelting is performed later, thereby completing the production of the first master alloy.

[0054] Next, the first master alloy produced is melted, and the melting process is as follows.

[0055] 1) Pure aluminum (AL) is loaded into an electric melting furnace and the temperature is set to 700°C to 750°C to proceed with the first melting.

[0056] 2) Once the pure aluminum is completely melted, Si (silicon) is added to the molten aluminum and the process is waited until the Si (silicon) is completely melted.

[0057] 3) Once the Si (silicon) is completely melted, the first master alloy is added and melted. After adding the first master alloy, the set temperature is maintained at 700℃ to 750℃.

[0058] Next, the first master alloy produced and the second master alloy made of aluminum (Al)-vanadium (V) are sequentially charged into a melting furnace and melted. Once the first master alloy is completely melted, the second master alloy is charged while maintaining a set temperature and maintained until the second master alloy is completely melted. Here, the second master alloy made of aluminum (Al)-vanadium (V) may be produced in-house, or a general aluminum (Al)-vanadium (V) alloy may be used.

[0059] Next, magnesium (Mg) and zinc (Zn) are charged into the melting furnace in which the first master alloy and the second master alloy are melted, and then melted to produce an aluminum alloy in the form of an ingot.

[0060] In addition, aluminum alloy in the form of an ingot can be melted in an electric melting furnace and aluminum castings can be completed using a die casting method with a mold.

[0061] In general aluminum alloy manufacturing methods, a large amount of heat is required because work must be performed at a considerably high temperature to add materials with a melting point higher than that of the main material, aluminum.

[0062] However, the method for manufacturing an aluminum alloy according to the present invention can be operated in a small melting furnace because it selects a portion of the materials (components) and melts them sequentially in order of lowest melting point to produce a first master alloy, and when the first master alloy is remelted to finally produce an aluminum alloy, the materials are melted even at a low heat amount, so efficient operation is possible and the accuracy of the composition is also increased.

[0063] For the aluminum alloy produced by the above method, a tensile test specimen was prepared from a casting produced in a mold with a width of 6 mm, a thickness of 3 mm, and a length of 100 mm in the size of a plate-shaped sub-test specimen according to ASTM E8 standards, and a tensile test was conducted on a universal testing machine at a cross header speed of 0.05 m / min to measure the tensile strength and elongation.

[0064] The measurement results showed a tensile strength of 297.2 to 372.8 MPa and an elongation of 11.4% to 25.8%. In other words, it can be confirmed that the aluminum alloy according to the present invention is an aluminum alloy that has relatively high tensile strength and high elongation, even though it does not contain copper and does not undergo a heat treatment process.

[0065] Meanwhile, regarding the aluminum alloy produced by the above method, a casting material produced in a mold was processed on a general-purpose lathe to form a compression test specimen with a diameter of 3.95 to 4.05 mm and a length of 9.9 to 10.3 mm, and a compression test was conducted on a universal testing machine at a cross header speed of 0.05 m / min to measure the compressive strength and strain. The measurement results showed a compressive strength of 478.5 MPa to 534.5 MPa and a strain of 36.1% to 42.5%. In other words, it can be confirmed that the aluminum alloy according to the present invention is an aluminum alloy that possesses relatively high compressive strength and good strain, even though it does not contain copper and does not undergo a heat treatment process.

[0066] Figure 1 is an optical microscope image of an aluminum alloy according to the present invention. The optical microscope image of Figure 1 is at a magnification of 500x, and from the image of Figure 1, Al3Mg2 and Mg2Si structures that affect strength and elongation can be observed. The aluminum alloy of the present invention can not only improve elongation but also secure appropriate strength by containing appropriate amounts of silicon (Si) and magnesium (Mg) without including copper or performing heat treatment.

[0067] Figure 2 is a scanning electron microscope image of an aluminum alloy according to the present invention, showing the distribution of added elements.

[0068] Table 1 below shows the composition of high elongation non-heat-treated aluminum that does not contain copper according to the embodiment of the present invention in weight percent.

[0069] [Unit: %] SiMnFeMgCrNiVTiZnAl Alloy 1 2.15 0.02 0.086.5 0.01 0.002 0.01 0.15 0.05 Remainder Alloy 2 2.00 0.03 0.108 0.00 0.05 0.002 0.05 0.01 0.20 Remainder Alloy 3 3.20 0.02 0.097.10 0.01 0.001 0.08 .010.02 remainder alloy 42.800.020.109.000.090.0030.020.100.02 remainder alloy 52.500.050.257.500.020.090.050.020.01 remainder alloy 63.800.200.058.500.030.0020.070.350.01 remainder alloy 73.000.040.037.100.020.0030.500.500.03 Remainder Alloy 82.000.030.106.800.040.050.030.020.10 Remainder Alloy 92.200.020.026.700.080.0090.050.050.01 Remainder Alloy 103.000.060. 308.000.05 0.010.010.03 0.05 Remainder Alloy 1 13.5 00.010.01 7.5 00.03 0.03 0.04 0.04 0.03 Remainder Comparison 1 0.000.6 00.01 10.00.01 0.7 00.55 Remainder Comparison 2 7.000.01 1.10 4.000.2 00.100.05 Remainder

[0070] In Table 1, Alloys 1 to 11 are aluminum alloys according to the present invention, with their constituent elements and their contents expressed in weight percent, and Comparison 1 and Comparison 2 are aluminum alloys for comparison with aluminum alloys 1 to 11 according to the present invention, with their constituent elements and their contents expressed in weight percent. As can be seen from Table 1 above, the aluminum alloy according to the present invention comprises 2.0 to 3.80 wt% silicon (Si), 0.01 to 0.05 wt% manganese (Mn), 0.01 to 0.25 wt% iron (Fe), 6.50 to 9.00 wt% magnesium (Mg), 0.01 to 0.09 wt% chromium (Cr), 0.001 to 0.09 wt% nickel (Ni), 0.01 to 0.50 wt% vanadium (V), 0.01 to 0.50 wt% titanium (Ti), 0.01 to 0.20 wt% zinc (Zn), and the remainder being aluminum (Al) and a production-inducing material. Among the above alloys, alloys 1 to 5 and alloy 9 exhibit good mechanical properties, and these aluminum alloys contain 2.0 to 3.20 wt% silicon (Si), 0.02 to 0.05 wt% manganese (Mn), 0.02 to 0.25 wt% iron (Fe), 6.50 to 9.00 wt% magnesium (Mg), 0.01 to 0.09 wt% chromium (Cr), 0.001 to 0.09 wt% nickel (Ni), 0.01 to 0.08 wt% vanadium (V), 0.01 to 0.15 wt% titanium (Ti), 0.01 to 0.20 wt% zinc (Zn), and the remainder aluminum (Al) and production-inducing materials.

[0071] Table 2 below shows the results of tensile tests conducted to evaluate the mechanical properties of aluminum alloys 1 to 11 according to the present invention and alloy comparisons 1 to 2. Specifically, for alloys 1 to 11, tensile test specimens were prepared from castings produced in a mold, with a width of 6 mm, a thickness of 3 mm, and a length of 100 mm, in the size of a plate-shaped sub-specimen according to ASTM E8 standards. Tensile tests were then performed on a universal testing machine at a cross header speed of 0.05 m / min to measure tensile strength and elongation.

[0072] Alloy Code Tensile Strength (MPa) Elongation (%) Alloy 13 20.3 25.8 Alloy 23 32.4 19.2 Alloy 33 72.8 11.4 Alloy 43 20.2 14.0 Alloy 53 48.9 16.6 Alloy 63 12.4 13.0 Alloy 73 00.0 13.7 Alloy 82 98.4 15.1 Alloy 93 38.1 15.0 Alloy 103 14.2 12.0 Alloy 112 97.2 12.9 Comparison 12 57.2 5.0 Comparison 23 30.8 7.7

[0073] As can be seen from Table 2 above, the tensile strength of alloys 1 to 11 was 297.2 to 372.8 MPa, and the elongation was 11.4% to 25.8%. This confirms that the aluminum alloy according to the present invention is an aluminum alloy that has relatively high tensile strength and high elongation, even though it does not contain copper and does not undergo a heat treatment process. In contrast, Comparison 1 does not contain silicon (Si) and has a composition containing manganese (Mn), magnesium (Mg), titanium (Ti), and zinc (Zn) in the range of alloys 1 to 11 of the present invention, and it can be seen that although the tensile strength is low, the elongation is significantly low. Comparison 2 has a composition containing manganese (Mn) and magnesium (Mg) in the range of alloys 1 to 11 of the present invention, and silicon (Si), iron (Fe), and vanadium (V) in the range of alloys 1 to 11 of the present invention, and it can be seen that the strength is similar to alloys 1 to 11 of the present invention, but the elongation is low.

[0074] FIG. 3 is a graph showing the tensile strength and elongation of aluminum alloys 1 and 2 according to the present invention compared with comparisons 1 and 2. In this graph, the horizontal axis represents an elongation of 0 to 30%, and the vertical axis represents a strength value of 0 to 350 MPa. In this graph as well, it can be confirmed that the elongation of alloys 1 and 2 is significantly superior to that of comparisons 1 and 2.

[0075] Table 3 below shows the results of compression tests conducted to evaluate the mechanical properties of aluminum alloys 1 to 11 and comparisons 1 to 2 according to the present invention. Specifically, for alloys 1 to 11, a casting material produced in a mold was processed into a compression test specimen with a diameter of 3.95 to 4.05 mm and a length of 9.9 to 10.3 mm on a general-purpose lathe, and a compression test was performed on a universal testing machine at a cross header speed of 0.05 m / min to measure the compressive strength and strain.

[0076] Alloy Code Compressive Strength (MPa) Strain (%) Alloy 1500 0.8 36.6 Alloy 2500 5.1 36.2 Alloy 3534.5 40.3 Alloy 4526.6 38.8 Alloy 5520.0 39.5 Alloy 6501.6 36.1 Alloy 7483.7 37.5 Alloy 8517.7 42.0 Alloy 9492.5 40.4 Alloy 10478.5 39.1 Alloy 11504.2 42.5 Comparison 1479.6 32.8 Comparison 2572.8 29.8

[0077] As can be seen from Table 3 above, the compressive strength of alloys 1 to 6 was 478.5 MPa to 534.5 MPa, and the strain was 36.1% to 42.5%. That is, it can be confirmed that the aluminum alloy according to the present invention is an aluminum alloy that has relatively high compressive strength and good strain, even though it does not contain copper and does not undergo a heat treatment process. In contrast, Comparison 1 is a composition containing silicon (Si) within the range of alloys 1 to 11 of the present invention and manganese (Mn), magnesium (Mg), titanium (Ti), and zinc (Zn) within the range of alloys 1 to 11 of the present invention, and when compared to alloys 1 to 11 of the present invention, it can be seen that the compressive strength is relatively low and the strain is significantly low. Comparison 2 is a composition containing manganese (Mn) and magnesium (Mg) within the range of alloys 1 to 11 of the present invention and silicon (Si), iron (Fe), and vanadium (V) within the range of alloys 1 to 11 of the present invention, and it can be seen that the compressive strength is excellent but the strain is very low. Figure 4 is a graph of compressive strength and strain that can be confirmed by comparing alloys 4 and 5 of the aluminum alloy according to the present invention with Comparisons 1 and 2. The horizontal axis of this graph represents a strain of 0 to 40%, and the vertical axis represents a strength value of 0 to 600 MPa. In this graph as well, it can be confirmed that the strain of alloys 4 and 5 is significantly superior to that of comparison 1 and comparison 2.

[0078] In addition, Figure 5 is a photograph comparing the surfaces of a conventional aluminum alloy (ALDC12) containing copper (Cu) and commonly used in the die-casting industry, and an aluminum alloy according to the present invention (Alloy 1) after a salt spray test. The salt spray test was conducted for 96 hours at a temperature of 35°C using a 5% NaCl solution according to the standard specification KS D 9502:2024. The conventional aluminum alloy (ALDC12) contains some copper and shows red corrosion after the salt spray test, whereas the photograph of Alloy 1 of the present invention after the salt spray test shows no red corrosion and no pinholes were observed.

[0079] The invention described above is merely illustrative, and those skilled in the art will readily understand that various modifications and equivalent alternative embodiments are possible therefrom. Therefore, it will be understood that the invention is not limited only to the forms mentioned in the detailed description above. Accordingly, the true technical scope of protection of the invention should be determined by the technical spirit of the appended claims. Furthermore, the invention should be understood to include all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims.

Claims

A high-elongation non-heat-treatable aluminum alloy containing 2.0 to 5.0 wt% silicon (Si), 0.02 to 0.45 wt% manganese (Mn), 0.00 to 0.50 wt% iron (Fe), 6.00 to 9.00 wt% magnesium (Mg), 0.10 wt% or less chromium (Cr), 0.10 wt% or less nickel (Ni), 0.50 wt% or less vanadium (V), 0.50 wt% or less titanium (Ti), 0.50 wt% or less zinc (Zn), the remainder being aluminum (Al) and copper containing production-inducing substances. A high-elongation, non-heat-treatable aluminum alloy containing 2.0 to 3.80 wt% silicon (Si), 0.01 to 0.05 wt% manganese (Mn), 0.01 to 0.25 wt% iron (Fe), 6.50 to 9.00 wt% magnesium (Mg), 0.01 to 0.09 wt% chromium (Cr), 0.001 to 0.09 wt% nickel (Ni), 0.01 to 0.50 wt% vanadium (V), 0.01 to 0.50 wt% titanium (Ti), 0.01 to 0.20 wt% zinc (Zn), the remainder being aluminum (Al) and copper, which is a production-inducing substance.

3. In Paragraph 2, The above aluminum alloy is produced in the form of an ingot by including the steps of: producing a first master alloy comprising aluminum (Al), nickel (Ni), manganese (Mn), iron (Fe), chromium (Cr), and titanium (Ti); sequentially melting the first master alloy and a second master alloy comprising aluminum (Al) and vanadium (V) in a melting furnace; and, once the melting of the first master alloy and the second master alloy is completed, charging magnesium (Mg) and zinc (Zn) into the melting furnace to melt them. The above-mentioned first master alloy is produced by weighing each element according to the weight percentage of the alloy on an electronic balance, placing a portion of aluminum into an electric furnace and heating it, and once the aluminum is melted, first charging and melting nickel (Ni), after the nickel (Ni) is melted, charging and melting manganese (Mn), after the manganese (Mn) is melted, charging and melting iron (Fe) and chromium (Cr), and finally charging and melting titanium (Ti), and once the titanium (Ti) is melted, additional aluminum is charged. The melting of the first master alloy is carried out by charging pure aluminum (AL) into the melting furnace and melting it, and after the pure aluminum (AL) is melted, charging silicon (Si) and melting it, and after the silicon (Si) is melted, charging the first master alloy and melting it. A copper-free, high-elongation, non-heat-treatable aluminum alloy characterized by melting the second master alloy by loading the second master alloy into the melting furnace while maintaining a set temperature after the first master alloy has been melted.

4. In Paragraph 3, The above aluminum alloy is a copper-free, high-elongation, non-heat-treatable aluminum alloy characterized by having a tensile strength of 297.2 to 372.8 MPa, an elongation of 11.4% to 25.8%, a compressive strength of 478.5 MPa to 534.5 MPa, and a strain of 36.1% to 42.5%.

5. A non-copper-containing, high-elongation, non-heat-treated aluminum alloy casting manufactured by casting the aluminum alloy of any one of claims 1 to 4.

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