JP2008127630A - Aluminum alloy for casting, aluminum die-cast product using the same alloy, and method for producing the product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy for casting having excellent casting properties and productivity; to provide an aluminum die-cast product using the same alloy; and to provide a method for producing the product. <P>SOLUTION: The aluminum alloy for casting comprises, by mass, 9.0 to 11.0% Si, 0.05 to 0.35% Mg, ≤0.1% Cu, 0.05 to 0.40% Fe, 0.3 to 0.5% Mn, 0.0020 to 0.0600% Li, and the balance aluminum with inevitable impurities. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aluminum alloy for casting, an aluminum die-cast product using the alloy, and a manufacturing method of the product.

  The die-casting method has attracted much attention as a method for producing aluminum products because it has advantages such as excellent formability and productivity over thin-walled castings. In particular, manufacturers in the automotive industry are now increasingly using high-quality die castings when producing weldable automotive structural parts with high extensibility.

  So far, many aluminum alloys, their alloy products or their production methods have been proposed. As a prior art, there is one that discloses a die-cast alloy and an alloy product thereof (for example, see Patent Document 1). Specifically, in Patent Document 1, in mass%, Si: 9.5 to 11.5%, Mg: 0.1 to 0.5%, Cu: 0.03% or less, Fe: 0.15% or less , Zn: 0.10% or less, Ti: 0.15% or less, Sr: 0.0030 to 0.0300%, and die cast alloys containing inevitable impurities and products thereof are disclosed, and the Si content is Al- By making it close to the eutectic point (11.7% by mass) of the Si binary system, the hot water flow at the time of die casting is ensured. Further, by setting Mn to a higher content than usual (JIS standard ADC12, ADC10, etc.), characteristics such as prevention of seizure to the mold and spreadability are improved. Furthermore, by restricting Fe to 0.15% by mass or less, generation of an Al—Si—Fe-based compound phase having a high notch effect is reduced, and Sr is added in an amount of 0.0030 to 0.0300% by mass. The crystallization size of the eutectic Si phase has been refined to improve material properties in the as-cast state (non-heat treatment).

  Some also disclose a method for producing an aluminum product using a die casting method (see, for example, Patent Document 2). Specifically, in Patent Document 2, in mass%, Si: 9.5 to 11.5%, Mg: 0.3 to 0.5%, Cu: 0.1% or less, Fe: 0.15% or less A manufacturing method is disclosed in which a formed body obtained by high-vacuum die casting (50 hPa or less) is subjected to a heat treatment having a malleability using an aluminum alloy that contains aluminum and the balance of aluminum and inevitable impurities.

  In addition, there are those that disclose a casting alloy using a die casting method (see, for example, Patent Document 3). Specifically, in Patent Document 3, by mass, Si: 8.5 to 10.5%, Mg: 0.06% or less, Mn: 0.3 to 0.8%, Cu: 0.03% Hereinafter, Fe: 0.15% or less, Zn: 0.10% or less, Ti: 0.15%, Mo: 0.05 to 0.5%, Sr: 0.0030 to 0.0300%, or Na: 0 0005-0.0030% and / or Ca: 0.0001-0.0030 is an essential component, and a highly cast die cast alloy containing Al and unavoidable impurities in the balance and a component by this are disclosed. ing.

Furthermore, some non-heat-treatable aluminum alloys for die casting, products by a die casting method, and manufacturing methods thereof are disclosed (for example, see Patent Document 4). Specifically, in Patent Document 4, the mass ratio of Mg and Si contained in the aluminum alloy is 0.1 to 0.5 and Si: 3.5 to 5.0%, Mg: 0.35 to 2.5%, Mn: 0.3 to 1.5%, Cu: 0.03% or less, Fe: 0.15% or less, Ti: 0.20% or less as essential elements, the balance being aluminum and inevitable A non-heat-treatable aluminum alloy for die casting made of impurities is disclosed. In addition, by increasing the Mg content to an upper limit of 2.5% by mass, solid solution strengthening is increased, and material properties are improved in an as-cast state (non-heat treatment).
Japanese Patent No. 3255560 (pages 2 to 3) JP 2001-198559 A (pages 2 to 3) JP 2004-225160 A (pages 2 to 5) Japanese Patent Laying-Open No. 2005-82865 (pages 2 to 5)

In the invention of Patent Document 1, since the concentration of impurities in general is reduced, Fe is maintained at a level lower than that of an existing die-casting alloy member of 0.15% by mass or less in particular. There is a problem that an increase in refining costs for high purity is inevitable. Further, the element Sr added in a small amount has an effect of affecting the characteristics of the alloy member. If the amount of Sr added is less than the lower limit, eutectic Si cannot be refined, and if it exceeds the upper limit, Al ₄ Sr compound is formed and crystallized. As a result, the toughness of the alloy member is reduced (so-called “over modification effect”), so in the invention of Patent Document 1, the Sr content is limited to a very small range of 0.0030 to 0.0300 mass%, and strict component management is performed. There is also a problem that it takes time and effort to produce the alloy by work.

  Further, in the invention of Patent Document 2, as in the invention of Patent Document 1, an Al—Si-based component close to the eutectic composition is mainly used, but the addition of the element Sr is omitted. For this reason, in the as-cast state (non-heat treatment), desired material characteristics (for example, improved ductility) of the alloy member cannot be obtained. Moreover, since it is essential to add heat treatment, it leads to an increase in production cost. Furthermore, since the heat treatment is performed, the product may be distorted due to the heat treatment of the cast product in some cases, and there is a problem that the dimensional accuracy of the product is lowered.

  Moreover, in the invention of Patent Document 3, it is almost the same as the main composition in the invention of Patent Document 1, and newly contains 0.05 to 0.5% by mass of Mo as an essential element, and material properties in an as-cast state. In particular, the improvement of the spreadability is embodied, but since a relatively expensive element Mo is additionally used, there is a problem that the production cost is increased.

  In addition, in the invention of Patent Document 4, the main composition of the alloy member is Al—Si—Mg, but the content of elemental Si is as low as 3.5 to 5.0 mass% compared to Patent Documents 1 to 3. Content level. For this reason, the reduction of the eutectic reaction latent heat release amount of Al-Si during casting solidification due to the low content of element Si, and the expansion of the solidification temperature range caused by the reduction of eutectic reaction latent heat release amount of Al-Si. Further, there is a problem that deterioration of casting characteristics (such as molten metal flow property, seizure property to a mold, and cracking property) of the alloy member is likely to occur.

  This invention is made | formed in view of the said actual condition, and makes it a subject to provide the aluminum alloy for casting excellent in the casting characteristic and productivity, the aluminum die-cast product using the alloy, and the manufacturing method of the product.

  The aluminum alloy for casting of the present invention has Si: 9.0 to 11.0% by mass, Mg: 0.05 to 0.35% by mass, Cu: 0.1% by mass or less, Fe: 0.05 to 0.40. Including mass%, Mn: 0.3-0.5 mass%, Li: 0.0020-0.0600 mass%, and the balance consists of aluminum and inevitable impurities.

  Si contained in the composition of the aluminum alloy is an element that affects the flowability and mechanical properties of the aluminum alloy. In the present invention, by setting Si to 9.0% by mass or more, it is possible to suppress a decrease in molten metal flow along with a decrease in the amount of Al-Si eutectic crystallized during solidification, and flow into the mold. It is possible to avoid the occurrence of product defects due to a shortage of materials or non-rotation. Moreover, by setting Si to 11.0% by mass or less, the eutectic point in the Al—Si binary system in the aluminum alloy does not exceed 11.7%, and the primary Si phase does not start to crystallize. . For this reason, the fall of the ductility of an alloy material can be suppressed. Thus, the aluminum alloy for casting according to the present invention can limit the Si content to 9.0 to 11.0% by mass, and can improve the hot water flow and mechanical properties of the aluminum alloy.

Mg contained in the composition of the aluminum alloy (Al—Si alloy) is an element that affects the mechanical properties of the alloy. By adding a small amount of Mg, an Mg ₂ Si crystallization phase during solidification and an Mg ₂ Si-based precipitation phase (precursor structure) immediately after solidification occur. In the present invention, by setting the Mg in 0.05 mass% or more, without crystallization of _Mg 2 Si is reduced, casting cracks due to decreased the ternary eutectic reaction volume of _Al-Si-Mg 2 Si The occurrence of such problems can be prevented. At the same time, the strength of the alloy material can be prevented from being lowered by maintaining the amount of precipitation of the Mg ₂ Si-based precipitation phase within the required range. Further, by setting the Mg in 0.35 mass%, the amount of Mg 2 _Si based precipitates phase immediately after solidification is appropriately suppressed, it is possible to prevent a decrease in ductility of the alloy material. Thus, the casting aluminum alloy of the present invention can limit the Mg content to 0.05 to 0.35% by mass and improve the mechanical properties of the aluminum alloy.

  Further, Cu contained in the composition of the aluminum alloy is an element that affects the corrosiveness of the alloy. In the present invention, by setting Cu to 0.1 mass% or less, it is possible to suppress an increase in Al-Cu-based crystallization or precipitation phase formation in the aluminum matrix. That is, the formation of a local metal battery is suppressed in a very small region in the metal structure, and the corrosion resistance of the alloy material is improved.

Further, Fe contained in the composition of the aluminum alloy has an effect of preventing seizure of the alloy material to the mold during casting. In the present invention, by setting Fe to 0.05% by mass or more, the crystallization amount of β iron-based compounds (Al ₄ FeSi, Al ₅ FeSi, etc.) in the aluminum matrix is maintained within a necessary range, and die casting is performed. The effect of preventing seizure of the alloy material to the mold during casting is improved. Further, in the conventional method, an aluminum alloy in which the Fe content is 0.15% by mass or less is generally used as an aluminum alloy for the purpose of improving the mechanical properties (particularly the ductility) of the alloy. The aluminum alloy of the invention is improved in the alloy material structure by addition of element Li described later, and the upper limit (0.15% by mass) of the upper limit of the Fe content is relaxed to greatly exceed 0.15% by mass. 0.40 mass% Fe can be contained, the amount of β-iron compound crystallization in the aluminum matrix is maintained within the required range, and the effect of preventing seizure of the alloy material to the mold during die casting It is possible to prevent a decrease in mechanical properties (particularly spreadability) associated with the interspersing of the acicular iron-based compound phases. As described above, the aluminum alloy of the present invention limits the Fe content to 0.05 to 0.40% by mass, improves the mechanical properties of the aluminum alloy and at the same time prevents the alloy material from sticking to the mold. can do.

Further, Mn contained in the composition of the aluminum alloy has an effect of preventing seizure of the alloy material at the time of casting to the mold, similarly to Fe. In the present invention, the amount of Al-Mn compound (Al ₆ Mn, Al ₁₂ Mn ₃ Si, Al ₁₂ Mn ₂ Si _2, etc.) produced on the casting surface is set by setting Mn to 0.3% by mass or more. This increases the effect of preventing the alloy material from sticking to the mold. In addition, by setting Mn to 0.5% by mass or less, the production amount of the Al—Mn-based compound on the casting surface is suppressed, and while the effect of preventing seizure of the alloy material to the mold is enhanced, Al—Mn An increase in crack generation sites and propagation paths accompanying an increase in the amount of crystallization of the system compound phase can be suppressed, and a decrease in the ductility of the alloy material can be suppressed. As described above, the aluminum alloy of the present invention limits the Mn content to 0.3 to 0.5% by mass to improve the mechanical properties of the aluminum alloy and at the same time prevent the alloy material from sticking to the mold. can do.

In addition, when eutectic Si is refined in an Al-Si-based aluminum alloy, Sr and Na have been conventionally used as improvement elements, and especially the improvement effect during casting and its sustainability (in a molten metal holding furnace). Sr has been used most frequently due to the degree of wear. However, in the improvement treatment with Sr, in order to avoid the deterioration of the ductility of the material (over modification phenomenon) due to the formation of Al ₄ Si crystals due to excess, it is relatively narrow, generally 0.0030 to 0.0300 mass% or less. Strict component management in the range is necessary. Therefore, it takes time for production, which is disadvantageous for improving productivity. Therefore, as a result of diligently studying an improved element that replaces the conventional Sr, the present invention shows that Li has an eutectic Si improving effect equal to or higher than that of Sr, and the suitable content range of Li is wider. I came to find it. That is, in the present invention, the allowable range of the content of Li as an improved element is 0.0020 to 0.0600 mass%, and the allowable range of the content of the conventional improved element Sr (0.0030 to 0.0300 mass%). ) Is much wider than the allowable range. For this reason, in the aluminum alloy for casting of this invention, productivity can be improved, maintaining the refinement | miniaturization effect of eutectic Si sufficiently.

  Thus, according to the aluminum alloy for casting of the present invention, in die casting, it has excellent casting characteristics and mold releasability, and the obtained die casting product is an as-cast high mechanical property, particularly It has excellent ductility and productivity. Moreover, the die-cast product by the aluminum alloy for casting of this invention is a thing suitable for the use of the automotive structural component by which toughness is requested | required.

Moreover, it is preferable that the aluminum alloy for casting of this invention further contains 0.05-0.18 mass% Ti and Zr in total. When an aluminum alloy for casting is refined, when Ti and Zr are added as improving elements, Al ₃ Zr or Al ₃ Ti compounds are generated by peritectic reaction during casting solidification. These compounds become solidification nuclei of the primary α-Al phase. As a result, the crystal structure is further refined and the mechanical properties (strength and spreadability) are improved. In this invention, the aluminum alloy which has high intensity | strength and ductility can be obtained by refinement | miniaturization process by setting content of Ti and Zr contained in an aluminum alloy to 0.05 mass% or more in total. On the other hand, since this refinement effect is saturated when it exceeds 0.18% by mass, by setting the total content of Ti and Zr to 0.18% by mass or less, extra material due to excessive content of Ti and Zr Increase in cost can be prevented.

  The manufacturing method of the aluminum die-cast product of the present invention is characterized by manufacturing by the die-casting method using the above-described aluminum alloy for casting. The method for producing an aluminum die-cast product provided by the present invention can provide an aluminum die-cast product particularly excellent in ductility and toughness by using a high vacuum die casting method when casting the above-described aluminum alloy.

  The aluminum die-cast product of the present invention is produced by the above-described method for producing an aluminum die-cast product. The aluminum die-cast product provided by the present invention is based on the above-described method for producing an aluminum die-cast product, and does not require heat treatment after die-casting, so that a die-cast product having excellent mechanical properties can be obtained.

  The aluminum die-cast product of the present invention is preferably an automobile structural member and an impact absorbing member. For example, it can be used for automobile frames, suspensions or link parts.

  According to the casting aluminum alloy of the present invention, in die casting, it has excellent casting characteristics and die-proofing property, that is, mold release property, and the obtained die casting product is as cast and has high mechanical strength, that is, tensile strength. It has strength, proof stress, hardness, high elongation, that is, high ductility, and excellent productivity. Moreover, the die-cast product by the aluminum alloy for casting of this invention is a thing suitable for the use of the automotive structural component by which toughness is requested | required.

  The aluminum alloy for casting of the present invention has Si: 9.0 to 11.0% by mass, Mg: 0.05 to 0.35% by mass, Cu: 0.1% by mass or less, Fe: 0.05 to 0.40. Including mass%, Mn: 0.3 to 0.5 mass%, Li: 0.0020 to 0.0600 mass%, and the balance may be made of aluminum and inevitable impurities.

  The Si content is preferably in the range of 9.0 to 11.0% by mass and close to the lower limit of 9.0% by mass. For example, 9.0-10.0 mass% is preferable. The Mg content is better in the range of 0.05 to 0.35% by mass and close to the lower limit of 0.05% by mass. For example, 0.05-0.15 mass% is preferable. A smaller amount of Cu is better at 0.1% by mass or less. For example, 0.01-0.05 mass% is preferable. The Fe content is better in the range of 0.05 to 0.40% by mass, close to the lower limit of 0.05% by mass. For example, 0.05 to 0.30 mass% is preferable. The Mn content is preferably in the range of 0.3 to 0.5% by mass and close to the upper limit of 0.5% by mass. For example, 0.3-0.4 mass% is preferable. The content of Li is preferably in a range close to the upper limit of 0.0600 mass% at 0.0020 to 0.0600 mass%. For example, 0.0080-0.0600 mass% is preferable.

When the Li content is 0.0020% by mass or more, the effect of refining eutectic Si is high, and a clear improvement in alloy characteristics is recognized. On the other hand, when the Li content is 0.0600% by mass or less, the generation of Al—Li compounds (LiAlO ₂ , Li ₂ O, δ-AlLi non-equilibrium crystallization phase) is suppressed, and the alloy material exhibits Ductility is improved.

  Moreover, the aluminum alloy for casting of this invention can contain 0.05-0.18 mass% Ti and Zr further in total. Further, the total content of Ti and Zr is preferably in the range of 0.10 to 0.15% by mass. When the content of Ti and Zr is set to 0.10 to 0.15 mass% in total, the effect of refining by Ti and Zr becomes remarkable, which is most advantageous for improving the productivity of the aluminum alloy.

  The method for producing an aluminum die cast product of the present invention can be produced by the die casting method using the above-described aluminum alloy for casting. The method for producing an aluminum die-cast product provided by the present invention can provide an aluminum die-cast product particularly excellent in ductility and toughness by using a high vacuum die casting method when casting the above-described aluminum alloy.

  The aluminum die-cast product of the present invention can be produced by the above-described method for producing an aluminum die-cast product. The aluminum die-cast product provided by the present invention is based on the above-described method for producing an aluminum die-cast product, and does not require heat treatment after die-casting, so that a die-cast product having excellent mechanical properties can be obtained.

  Moreover, the aluminum die-cast product of the present invention can be used as a structural member and an impact absorbing member for automobiles. For example, it can be used for automobile frames, suspensions or link parts.

  Hereinafter, the present invention will be specifically described based on examples.

150kg of various alloys shown in Table 1 are melted in a gas melting furnace, using a die casting machine with a clamping force of 800 tons, and high vacuum die casting (high vacuum by reducing the pressure inside the mold cavity for each shot) A box-shaped cast product having a mass of about 4.2 kg was casted by the above method. The casting conditions were as follows: the molten metal temperature was 670 ° C., the injection speed was 3 m / s, the injection pressure was 3.43 × 10 ⁷ Pa (350 kgf / cm ² ), the mold temperature was 170 to 250 ° C. The shot was thrown away to stabilize the mold temperature, and the following evaluation was performed while the cast product having a stable mold temperature was left as-cast (non-heat treated). Table 1 shows each chemical composition of the aluminum alloy of this example.

  As shown in Table 1, in Examples 1 to 12, the Si content is set to 9.0 to 11.0% by mass, the Mg content is set to 0.05 to 0.35% by mass, The Cu content is set to 0.1% by mass or less, the Fe content is set to 0.05 to 0.40% by mass, and the Mn content is set to 0.3 to 0.5% by mass. , Li content is set to 0.0020-0.0600 mass%. The element Sr exists in the composition of the alloy material as an inevitable impurity (about 0.0002 to 0.0006% by mass). The balance consists of Al and other inevitable impurities. In Examples 1 to 10, the contents of Ti and Zr are each set to 0.01% by mass or less, but in Examples 11 and 12, the contents of Ti and Zr are 0.08 to It is set to 0.15% by mass.

  As shown in Table 2, the comparative example is composed of comparative examples 1 to 10 and comparative example 11 using an AA standard 365 alloy equivalent material. Table 2 shows each chemical composition of the aluminum alloy of the comparative example.

  Comparative Examples 1 to 10 are comparative examples in which experiments were performed by changing the content of elements contained in the composition of the alloy material as shown below.

  As shown in Table 2, in Comparative Example 1, the Si content is set to be smaller than the allowable range (9.0 to 11.0% by mass) to 8.37% by mass, and the content of other alloy material compositions The experiment was conducted with the value set within the allowable range. In Comparative Example 2, the experiment was conducted by setting the Si content to be larger than the allowable range, 11.72% by mass, and setting the other alloy material compositions within the allowable range.

  In Comparative Example 3, the Mg content is set to be smaller than the allowable range (0.05 to 0.35 mass%), 0.01 mass%, and the contents of other alloy material compositions are set within the allowable range. The experiment was conducted. In Comparative Example 4, the experiment was performed by setting the Mg content to be larger than the allowable range, 0.44% by mass, and setting the other alloy material compositions within the allowable range.

  In Comparative Example 5, the Fe content is set to be smaller than the allowable range (0.05 to 0.40 mass%), is set to 0.03 mass%, and the contents of other alloy material compositions are set within the allowable range. The experiment was conducted. In Comparative Example 6, the experiment was conducted by setting the Fe content to be larger than the allowable range, 0.49% by mass, and setting the other alloy material compositions within the allowable range.

  In Comparative Example 7, the Mn content is set to be smaller than the allowable range (0.3 to 0.5 mass%), is set to 0.22 mass%, and the contents of other alloy material compositions are set within the allowable range. The experiment was conducted. In Comparative Example 8, the Mn content was set to be larger than the allowable range, 0.68% by mass, and the contents of other alloy material compositions were set within the allowable range.

  In Comparative Example 9, the Li content is set to be smaller than the allowable range (0.0020 to 0.0600 mass%), 0.0011 mass%, and the contents of other alloy material compositions are set within the allowable range. The experiment was conducted. In Comparative Example 10, the Li content was set larger than the allowable range, 0.0720% by mass, and the contents of other alloy material compositions were set within the allowable range.

  Comparative Example 11 is an experimental example using an AA standard 365 alloy equivalent material. Table 2 shows the content of each composition of the alloy material.

  Table 3 shows the results of measuring the mechanical properties and casting properties of the alloys using the aluminum alloy castings of the respective examples shown in Table 1. The mechanical characteristics refer to tensile characteristics, and include tensile strength, yield strength (0.2% yield strength), and elongation (breaking elongation). Casting properties include hot metal flow and seizure.

  Each box-shaped aluminum alloy cast product of Examples 1 to 12 shown in Table 1 was cut out as a plate-shaped tensile test piece from the central thickness 2 to 4 mm, and then the crosshead speed (tensile speed) 1 mm / min. The tensile properties were measured with an Amsler type testing machine. The tensile test piece is shown in FIGS. FIG. 1 shows a front view and dimensions of a plate-like tensile test piece. FIG. 2 shows the AA cross-sectional view and dimensions of the plate-like tensile test piece in FIG.

  Moreover, the molten metal flowability of the casting characteristics is the same as the overflow part (hot water side) on the counter-gate side where the difference in the appearance of each box-shaped aluminum alloy cast product of Examples 1 to 12 shown in Table 1, in particular, the difference in hot water performance appears. The degree of filling of the molten metal in the ladle part) and the vacuum suction runner part (passage) is evaluated by visual observation. In Table 3, “○” indicates good hot-water flow (all are densely packed), “△” indicates slightly good hot-water flow (partially insufficient filling), and “×” indicates hot-water flow. It indicates a defect (a lack of filling is conspicuous overall).

  Further, the seizure property of the casting characteristics is evaluated by observing the entire cast product, the biscuits, and the runners with the naked eye similarly to the method for measuring the hot water flow. In Table 3, “◯” indicates that there is no seizure, “Δ” indicates that seizure occurs in a very small part, and “x” indicates that seizure occurs in the whole area. Is.

  As can be seen from the tensile and casting property evaluation results of the alloys in Table 3, in all Examples 1 to 12 according to this embodiment, the tensile strength of the tensile properties is in the range of 260 to 280 MPa, 0.2% elongation) is in the range of 126 to 142 MPa, and the elongation is in the range of 8.3 to 11.2%.

  From this result, it can be seen that the cast product of the aluminum alloy of this example has excellent tensile properties. In particular, as can be seen from the measurement results of Examples 11 and 12 in Table 3, by adding Ti and Zr to the aluminum alloy within a total amount of 0.05 to 0.18% by mass, better tensile strength and yield strength are achieved. And the elongation rate could be obtained. Moreover, also in the casting characteristics, the molten metal hot water can closely fill the mold, and exhibits good hot water flowability. Further, the cast product does not seize on the mold and exhibits good seizure characteristics.

  Next, in Table 4, the results of measuring and evaluating the aluminum alloy castings of Comparative Examples 1 to 11 by the same evaluation method as in the examples are shown. Table 4 shows the evaluation results of the aluminum alloy castings of the comparative examples.

  As can be seen from the tensile and casting property evaluation results of the alloys shown in Table 4, in Comparative Examples 1 to 10 of this embodiment, the tensile strength of the tensile properties is in the range of 248 to 275 Mpa, and from the results of Examples 1 to 12 It was found that the tensile strength was low. Moreover, from the evaluation results of Comparative Examples 1 to 10, the yield strength characteristics (at 0.2% elongation) are in the range of 118 to 148 MPa, and the yield strength characteristics are inferior to the results of Examples 1 to 12. I understood. From the evaluation results of Comparative Examples 1 to 10, it was found that the elongation was in the range of 5.3 to 10.8%, which was inferior to the results of Examples 1 to 12. From this result, it was found that the cast product of the aluminum alloy of the present embodiment has excellent tensile properties as compared with the comparative example. Moreover, as shown in Table 4, it turned out that the casting characteristics of Comparative Examples 1, 5, 7, 8, 9, and 10 are inferior due to the difference in composition content among the alloy castings of Comparative Examples 1 to 10. .

  Examples and Comparative Examples were compared using Tables 1 to 4, and the following evaluation results were found.

  1. In Comparative Example 1, since the Si content is less than or equal to the allowable content range (9.0% by mass), the casting characteristics are inferior. In contrast, Examples 1 to 12 have stable and excellent casting characteristics.

  2. In Comparative Example 2, since Si is in the allowable content range (11.0% by mass) or more, tensile properties (particularly elongation) are inferior. On the other hand, Examples 1 to 12 have stable and excellent tensile properties.

  3. In Comparative Example 3, since Mg is within the allowable content range (0.05% by mass), tensile properties (particularly yield strength properties) are inferior. On the other hand, Examples 1 to 12 have stable and excellent tensile properties.

  4). In Comparative Example 4, since Mg is in the allowable content range (0.35 mass%) or more, tensile properties (particularly elongation) are inferior. On the other hand, Examples 1 to 12 have stable and excellent tensile properties.

  5. In Comparative Example 5, since Fe is within the allowable content range (0.05% by mass), casting characteristics (particularly seizure property) are inferior. In contrast, Examples 1 to 12 have stable and excellent casting characteristics.

  6). In Comparative Example 6, since Fe is in the allowable content range (0.40% by mass) or more, tensile properties (particularly elongation) are inferior. On the other hand, Examples 1 to 12 have stable and excellent tensile properties.

  7. In Comparative Example 7, since Mn is not more than the allowable content range (0.3% by mass), casting characteristics (particularly seizure characteristics) or tensile characteristics (particularly elongation) are inferior. In contrast, Examples 1 to 12 have stable and excellent casting characteristics.

  8). In Comparative Example 8, since Mn is not less than the allowable content range (0.5% by mass), casting characteristics (particularly, hot water flowability) are inferior. In contrast, Examples 1 to 12 have stable and excellent casting characteristics.

  9. In Comparative Example 9, since Li is less than or equal to the allowable content range (0.0020% by mass), tensile properties (particularly elongation) are inferior. On the other hand, Examples 1 to 12 have stable and excellent tensile properties.

  10. In Comparative Example 10, since Li is in the allowable content range (0.0600% by mass) or more, casting characteristics (particularly, hot water flowability) are inferior. In contrast, Examples 1 to 12 have stable and excellent casting characteristics.

  Moreover, as shown in Table 4, Comparative Example 11 is an experimental example using an AA standard 365 alloy equivalent material. From the tensile property data of Comparative Example 11, it was found that the tensile properties of Examples 1 to 12 of the present embodiment matched the AA standard. That is, the aluminum alloy casting of this embodiment satisfies the AA standard and has excellent tensile properties.

  The aluminum alloy for casting of the present invention, the aluminum die-cast product using the alloy, and the method for producing the same are used in fields requiring mechanical properties such as toughness of die-cast products by the aluminum alloy for casting, for example, automobile structural parts Can be used in such fields.

The front view and dimension of a plate-shaped tensile test piece are shown. FIG. 2 is a cross-sectional view taken along a line AA in FIG. 1 and dimensions of a plate-like tensile test piece.

Claims (5)

Si: 9.0 to 11.0% by mass,
Mg: 0.05 to 0.35 mass%,
Cu: 0.1% by mass or less,
Fe: 0.05-0.40 mass%,
Mn: 0.3 to 0.5% by mass,
Li: An aluminum alloy for casting containing 0.0020 to 0.0600 mass%, the balance being made of aluminum and inevitable impurities.   2. The casting aluminum alloy according to claim 1, wherein the alloy further contains 0.05 to 0.18 mass% of Ti and Zr in total.   A method for producing an aluminum die-cast product, wherein the aluminum alloy for casting according to claim 1 or 2 is produced by a die-casting method.   An aluminum die-cast product manufactured by the manufacturing method according to claim 3.   5. The aluminum die cast product according to claim 4, wherein the product is a structural member of an automobile.

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