JP6420553B2 - Aluminum alloy, aluminum alloy wire, aluminum alloy wire manufacturing method, aluminum alloy member manufacturing method, and aluminum alloy member - Google Patents

Description

  The present invention relates to an aluminum alloy suitable for a material of a structural member, an aluminum alloy wire suitable for a material of an aluminum alloy member such as a bolt, a manufacturing method thereof, an aluminum alloy member and a manufacturing method thereof. In particular, the present invention relates to an aluminum alloy wire having excellent strength and excellent workability.

  Since aluminum alloys are lighter than iron-based materials, they are used as materials for various structural members that are desired to be light. In particular, 6000 series aluminum alloys have strength next to 2000 series alloys and 7000 series alloys and are more excellent in corrosion resistance than 2000 series alloys and 7000 series alloys, and are therefore used in automotive parts and bolts. .

A6056 is mentioned as a high strength alloy among 6000 series alloys. A6056 is an alloy with high strength by increasing the concentration of Mg, Si, and Cu. The tensile strength of the T6 material reaches 425 MPa and the 0.2% proof stress reaches 375 MPa. Patent Document 1 has a high concentration of Mg, Si, and Cu as in A6056, and the ratio of the content of Mg ₂ Si and the total content of Mn and Cr is within a specific range. An aluminum alloy wire that is strong and excellent in formability (workability) to a bolt is disclosed.

JP2013-104122A

Kenji Higashi, “The New World of Alchemy Dreaming with First Principles (Part 1)”, Journal of Japan Institute of Light Metals, Japan Institute of Light Metals, 2010, Vol. 60, No. 8, p. 411-418 Kenji Higashi, “The New World of Alchemy Dreaming with First Principles (Part 2)”, Journal of Japan Institute of Light Metals, Japan Institute of Light Metals, 2010, Vol. 60, No. 9, p. 458-466 Yoshitomo Kato et al., “Effects of additive elements on the structure and mechanical properties of Al—Mg—Si alloys”, Abstracts of the 120th Spring Meeting of the Japan Institute of Light Metals (2011), Japan Society of Light Metals, 2011, p. 227-228 Yoshikazu Kato, et al. , “Effect of Alloy Elements on Microstructures and Mechanical Properties, Al-Mg-Si Alloys, ICAA 13: 13th International Conference on Aluminum Alloys, Ms. 1521-1526

  An aluminum alloy having excellent strength in plastic working such as rolling, wire drawing, head processing and rolling in bolt production, forging in production of cranks, etc. while having a strength equivalent to A6056, preferably higher. Development is desired.

  A6056 is difficult to cast and roll due to the high concentration of the additive element as described above, and is slightly inferior in workability among 6000 series alloys. In addition, in a member such as a spool valve or a crank, 0.2% proof stress substantially determines the allowable stress, so that it is desired that not only tensile strength but also 0.2% proof strength is excellent. Yes. Furthermore, A6056 is required to develop an aluminum alloy that is slightly lower in corrosion resistance and excellent in corrosion resistance than other 6000 series alloys such as A6061 and A6151.

  Although the aluminum alloy wire described in Patent Document 1 has a specific composition as described above, it has a tensile strength equal to or higher than that of A6056 and is excellent in formability to bolts. Further improvement in sex is desired.

  In particular, in an aluminum alloy wire used as a bolt material, plastic processing such as rolling and wire drawing is performed in the manufacturing process itself, and plastic processing such as head processing and rolling is performed in the manufacturing process of the bolt. Therefore, development of an aluminum alloy wire that is superior in workability is desired.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide an aluminum alloy that is excellent in strength and excellent in workability. Another object of the present invention is to provide an aluminum alloy wire having excellent strength and excellent workability, and a method for producing the same. Another object of the present invention is to provide an aluminum alloy member having excellent strength and a method for producing the same.

  The aluminum alloy of the present invention is, by mass, Si: more than 1.0% and 1.5% or less, Mg: 0.5% or more and 1.2% or less, Fe: 0.3% or more and 0.8% or less, Cu: 0% or more and 0.5% or less, Mn: 0% or more and 0.5% or less, Cr: 0% or more and 0.5% or less, the balance being Al and inevitable impurities, the content of Fe Is the Cu content or more, and the ratio of the excess Si content to the Fe content (excess Si amount) / (Fe amount) is 0.1 to 3.0.

  The aluminum alloy wire of the present invention is made of the aluminum alloy of the present invention.

The manufacturing method of the aluminum alloy wire of the present invention includes the following casting process, rolling process, and wire drawing process.
(Casting process) In mass%, Si: more than 1.0%, 1.5% or less, Mg: 0.5% or more, 1.2% or less, Fe: 0.3% or more, 0.8% or less, Cu: 0 %: 0.5% or less, Mn: 0% or more and 0.5% or less, Cr: 0% or more and 0.5% or less, the balance being Al and unavoidable impurities, and the content of Fe being the Cu An aluminum alloy having a composition in which (excess Si amount) / (Fe amount), which is a ratio of the excess Si content to the Fe content, is 0.1 or more and 3.0 or less. A process of casting to obtain a cast material.
(Rolling step) A step of rolling the cast material to obtain a rolled material.
(Wire drawing process) The process which draws the said rolling material and makes it a wire drawing material of a predetermined | prescribed wire diameter.

  The method for producing an aluminum alloy member of the present invention is an object in the process from the processing including plastic working to the aluminum alloy wire produced by the method for producing an aluminum alloy wire of the present invention until the production of the aluminum alloy member. And 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less.

  The aluminum alloy member of the present invention is made of the aluminum alloy of the present invention, has a tensile strength of 400 MPa or more, a 0.2% proof stress of 375 MPa or more, and a breaking elongation of 10% or more.

  The aluminum alloy of the present invention is excellent in strength and workability. The aluminum alloy wire of the present invention provides an aluminum alloy member having excellent strength and excellent workability. The method for producing an aluminum alloy wire of the present invention can produce an aluminum alloy member excellent in strength and can produce an aluminum alloy wire excellent in workability. The method for producing an aluminum alloy member of the present invention can produce an aluminum alloy member having excellent strength. The aluminum alloy member of the present invention is excellent in strength.

Sample No. produced in Test Example It is the microscope picture which observed the cross section of 1-1 aluminum alloy with the scanning electron microscope.

[Description of Embodiment of the Present Invention]
The present inventors have intensively studied based on the composition of a 6000 series aluminum alloy with the aim of being excellent in workability while having a strength equivalent to, preferably higher than, A6056. As a result, Cu, which is an element effective for improving the strength, is reduced or does not contain Cu, and the Fe content is relatively increased, and the Fe content and the Si content added excessively are within a specific range. Assuming that the specific composition is, an aluminum alloy having excellent strength and proof stress can be obtained by adjusting the solution treatment conditions. Moreover, since it was set as the said specific composition, since other additive elements can be reduced comparatively, ie, the concentration of a component can be suppressed, the knowledge that corrosion resistance, workability, and productivity can be improved was acquired. The present invention is based on the above findings. Hereinafter, the contents of the embodiment of the present invention will be listed and described first.

  (1) The aluminum alloy according to the embodiment is, in mass%, Si: more than 1.0% and 1.5% or less, Mg: 0.5% or more and 1.2% or less, Fe: 0.3% or more and 0.00. 8% or less, Cu: 0% to 0.5%, Mn: 0% to 0.5%, Cr: 0% to 0.5%, the balance being Al and inevitable impurities, The Fe content is not less than the Cu content, and the ratio of the excess Si content to the Fe content (excess Si amount) / (Fe amount) is 0.1 to 3.0. With composition. This composition is sometimes referred to as the first composition.

The excess Si amount is determined by the following <Formula 1> using the Si content (mass%) and the Mg content (mass%) in the aluminum alloy.
<Formula 1>
Excess Si amount = Si content − {(Mg content) / (24.3 × 2)} × 28.1

The aluminum alloy of the embodiment in which the Fe content is equal to the Cu content, preferably contains more Fe than Cu, and (excess Si content) / (Fe content) satisfies a specific range, is excellent in strength. Preferably, the aluminum alloy of the embodiment is excellent in yield strength and elongation. The reason is considered as follows. When an aluminum alloy containing excessive Si is subjected to a solution treatment at a relatively high temperature as described later, the solid solution precipitation state of Si concentrated near the crystal grain boundary is controlled and the grain boundary becomes brittle. Can be suppressed. In particular, when Cu is contained in a specific range, Si and Cu at the grain boundary are precipitated as a compound in alignment with the lattice of Al, and embrittlement of the grain boundary can be further suppressed. However, at the above-mentioned high temperature, the segregation of Si easily proceeds to the grain boundaries, and when the solution treatment temperature is too high, the amount of Si segregation can suppress the adverse effect caused by the segregation of Si (allowable). Capacity). Further, when the solution treatment time is too long or the temperature increase rate during solution treatment is too low, the amount of segregation of Si can exceed the allowable amount. As a result, a decrease in strength, a decrease in workability, and a decrease in yield strength can occur. On the other hand, when a relatively large amount of Fe is contained, crystal grains can be refined. If the number of grain boundaries increases due to the refinement of crystal grains, the amount of Si segregated per grain boundary can be reduced. In other words, even when solution treatment is performed at a relatively high temperature by containing Fe in a specific range, adverse effects due to segregation of Si can be reduced. As a result, in addition to the effect of improving the strength by precipitation hardening of precipitates such as Mg ₂ Si, an effect of suppressing grain boundary embrittlement can be obtained, so it is considered that the strength is excellent, and further, the proof stress and elongation are also excellent. Here, Fe has a very high solid solution strengthening ability. However, Fe is generally difficult to dissolve. Thus, as a result of studies by the present inventors, it has been found that a large amount of Fe can be dissolved in a matrix if the solidification rate is sufficiently increased by performing continuous casting or the like. Based on this knowledge, as will be described later, the solidification rate and the amount of Fe added are controlled, so that a relatively large amount of Fe is dissolved in the matrix to increase the strength. Thus, the aluminum alloy of the embodiment excellent in strength, preferably yield strength and elongation, can be suitably used for various structural members and materials thereof.

  In addition, the aluminum alloy of the embodiment has a smaller amount of Cu or no Cu than the conventional aluminum alloy described in A6056 and Patent Document 1, or a smaller amount of other elements (for example, Mn). Even if Zn or Zr is not essential, the strength and the proof stress are excellent as described above. As described above, the aluminum alloy of the embodiment having a relatively low concentration of the additive element is excellent in workability, and cracks and the like occur during processing in various plastic processing such as rolling, wire drawing, head processing, rolling, and forging. hard. Therefore, by using the aluminum alloy of the embodiment as a raw material, it is expected that various plastic processed materials can be manufactured satisfactorily and contribute to mass production of the plastic processed materials.

  (2) As an example of the aluminum alloy according to the embodiment, the content of each element in the composition is mass%, Si: more than 1.0%, 1.3% or less, Mg: 0.7% or more, 1.0 %: Fe: 0.3% to 0.6%, Cu: 0.1% to 0.4%, Mn: 0% to 0.3%, Cr: 0% to 0.3% And the above (excess Si amount) / (Fe amount) is 0.3 or more and 1.7 or less. This composition is sometimes referred to as a second composition.

  The above-mentioned form of the second composition in which the content of each element is more limited than the above-described first composition is more excellent in strength and workability. Furthermore, the above-mentioned form is more excellent in yield strength.

  (3) As an example of the aluminum alloy according to the embodiment, the composition further includes, in mass%, Ti: 0.001% to 0.1% and Zr: 0.05% to 0.2%. Examples include a form containing at least one selected element. This composition is sometimes referred to as a third composition.

  The form of the third composition containing at least one of Ti and Zr in addition to the elements of the first composition described above is likely to have a fine crystal structure. Therefore, the strength and workability are improved with the fine crystal structure. Can be expected.

  (4) As an example of the aluminum alloy according to the embodiment, the aluminum alloy is subjected to a solution treatment of 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less, and then 160 ° C. or more and 180 ° C. or less × 4 hours or more. The tensile strength after the aging treatment is 400 MPa or more, the 0.2% proof stress is 375 MPa or more, and the elongation at break is 10% or more.

  The said form is excellent in the intensity | strength, yield strength, and elongation after performing a solution treatment and an aging treatment on the above-mentioned specific conditions. From this, it can be said that an aluminum alloy member having excellent strength and further proof stress can be produced by using at least the solution treatment and the aging treatment using the aluminum alloy of the above form as a raw material. In addition, since the aluminum alloy of the embodiment is also excellent in workability, when the aluminum alloy of the above form is used as a raw material and further plastic processing is performed to produce an aluminum alloy wire or an aluminum alloy member, the plastic processing is excellent. Yes. Therefore, the said form can be utilized suitably for the raw material of the aluminum alloy wire which is excellent in intensity | strength, and also the proof stress, irrespective of the presence or absence of the plastic working in a manufacture process. Typical conditions used for this characteristic evaluation include a solution treatment of 570 ° C. × 30 minutes and an aging treatment of 170 ° C. × 16 hours. Depending on the composition, for example, in the second composition and the third composition described above, the tensile strength after the above specific solution treatment and aging treatment is 410 MPa or more, and the 0.2% proof stress is 385 MPa or more. And the elongation at break is 10% or more, the tensile strength is 420 MPa or more, the 0.2% proof stress is 395 MPa or more, and the elongation at break is 10% or more.

  (5) The aluminum alloy wire according to the embodiment is made of the aluminum alloy according to the embodiment described in any one of the above (1) to (4).

  Since the aluminum alloy wire of the embodiment is composed of the aluminum alloy of the embodiment excellent in workability, it can be suitably used as a material for an aluminum alloy member manufactured by plastic working such as a bolt or a crank. it can. In particular, the aluminum alloy wire of the embodiment is excellent in workability, and thus can be suitably used as a material for an aluminum alloy member that performs plastic processing such as bolts in multiple stages. And the aluminum alloy member which is excellent also in intensity | strength and also a yield strength can be manufactured by using the aluminum alloy wire of embodiment as a raw material. In particular, the aluminum alloy wire of the embodiment is subjected to plastic processing such as rolling or wire drawing at least, so that a coarse crystallized product is divided during plastic processing or a recrystallized structure caused by processing strain during solution treatment. Miniaturization can be performed, and surface defects such as shrinkage can be crushed. As a result, when the solution treatment and the aging treatment are performed under the specific conditions specified in (4) above, the above-described specific high strength, proof strength, and elongation are easily obtained, and even higher strength, proof strength, and Can have elongation.

(6) The manufacturing method of the aluminum alloy wire which concerns on embodiment is equipped with the following casting processes, a rolling process, and a wire drawing process.
(Casting process) In mass%, Si: more than 1.0%, 1.5% or less, Mg: 0.5% or more, 1.2% or less, Fe: 0.3% or more, 0.8% or less, Cu: 0 %: 0.5% or less, Mn: 0% or more and 0.5% or less, Cr: 0% or more and 0.5% or less, the balance being Al and unavoidable impurities, and the content of Fe being the Cu An aluminum alloy having a composition in which (excess Si amount) / (Fe amount), which is a ratio of the excess Si content to the Fe content, is 0.1 or more and 3.0 or less is continuous. A process of casting to obtain a cast material.
(Rolling step) A step of rolling the cast material to obtain a rolled material.
(Wire drawing process) The process which draws the said rolling material and makes it a wire drawing material of a predetermined | prescribed wire diameter.

  Since the manufacturing method of the aluminum alloy wire of the embodiment is made of an aluminum alloy having a specific composition in which the additive element has a relatively low concentration as a constituent component of the wire, the aluminum alloy wire (typically Can produce the aluminum alloy wire rod of the embodiment with high productivity. In particular, the method for producing an aluminum alloy wire according to the embodiment can provide an aluminum alloy wire that can be suitably used as a material for an aluminum alloy member having excellent mechanical properties.

  Moreover, the manufacturing method of the aluminum alloy wire of embodiment can fully dissolve the enumerated additional element (especially Fe) by performing the continuous casting which can be rapidly solidified. As a result, as described above, a strong solid solution strengthening effect by Fe and an effect of increasing grain boundaries by refinement of crystals (and an effect of suppressing grain boundary embrittlement) are obtained. Further, by performing continuous casting capable of rapid solidification, generation of crystallized substances other than Fe and Si and further coarsening can be suppressed. Therefore, in the above-described embodiment, it is possible to produce an aluminum alloy wire that is unlikely to be adversely affected by coarse crystallized Si and that provides an aluminum alloy member that is excellent in strength, proof stress, and elongation.

  (7) As an example of the manufacturing method of the aluminum alloy wire according to the embodiment, in the casting step, a form in which the solidification rate is 1 ° C./second or more can be mentioned. The solidification rate is {(casting temperature−liquidus temperature of aluminum alloy) / (time required for solidification after casting)}. The time required for solidification from casting can be measured, for example, by attaching a thermocouple to the inner wall of a mold (for example, a belt) provided in a continuous casting machine and measuring the temperature change from the casting temperature to the liquidus temperature. The liquidus temperature is obtained in advance from the composition of the aluminum alloy.

  In the above-mentioned form, the solidification rate is sufficiently high, and the formation and coarsening of the above-mentioned crystallized product can be satisfactorily suppressed, and Fe can be effectively dissolved. Therefore, the said form can manufacture the aluminum alloy wire from which the aluminum alloy member excellent also in intensity | strength and also yield strength can be obtained. In addition, it is possible to suppress the coarse crystallized product that becomes the starting point of cracking, and because the crystal can be made fine by such rapid cooling, it is excellent in plastic workability such as rolling and wire drawing. Aluminum alloy wire can be mass-produced with high productivity.

(8) As an example of the method for producing an aluminum alloy wire according to the embodiment, in the rolling step, a form in which the Z factor during rolling is 1.0 × 10 ¹⁰ or more and 1.0 × 10 ¹⁹ or less is exemplified. Z factor (Z) at the time of rolling is ε (strain rate, / sec), Q (active energy of aluminum, J / mol), R (gas constant, J / (K × mol)), T (absolute temperature) , K) using the following <Expression 2>.
<Formula 2> Z = ε × exp (Q / RT)
Here, Q = 1.42 × 10 ⁵ (J / mol) and R = 8.31 (J / (K × mol)).

  The said form makes it easy to reduce the coarse crystallization thing by dividing the crystallization thing produced | generated at the casting process by making Z factor into a specific range. As a result, the said form can improve wire drawing workability in the following wire drawing process, and can contribute to the mass production of an aluminum alloy wire. When an aluminum alloy member is manufactured by performing cutting, forging, plastic working, etc. using the obtained aluminum alloy wire, the productivity of the aluminum alloy member is also increased. Moreover, since the said form can reduce the coarse crystallization thing used as the starting point of a fracture | rupture, it can contribute to the improvement of the tensile strength of a aluminum alloy wire, and breaking elongation.

  (9) The manufacturing method of the aluminum alloy member according to the embodiment includes plastic working in the aluminum alloy wire manufactured by the manufacturing method of the aluminum alloy wire according to any one of the above (6) to (8). The object in the process until it processes and manufactures an aluminum alloy member is provided with the process of solution treatment of 550 degreeC or more and 580 degrees C or less x15 minutes or more and 120 minutes or less.

  The manufacturing method of the aluminum alloy member of the embodiment uses the aluminum alloy wire that is excellent in workability by being manufactured by the manufacturing method of the aluminum alloy wire of the embodiment, so that plastic processing and the like can be performed satisfactorily. And the manufacturing method of the aluminum alloy member of an embodiment performs solution treatment under specific conditions, more specifically, by performing solution treatment at a relatively high temperature, as described above, in the vicinity of the grain boundary In addition to controlling the solid solution precipitation state of Si, a solution material in which more Fe is dissolved in the matrix than when the solution treatment is performed at a normal temperature is obtained. By subjecting this solution material to an aging treatment separately, an aluminum alloy member having excellent strength and proof stress can be obtained. Therefore, the manufacturing method of the aluminum alloy member according to the embodiment can manufacture an aluminum alloy member that is excellent in strength and proof stress. In addition, the order of plastic working and solution treatment is not ask | required.

  (10) The aluminum alloy member according to the embodiment is made of the aluminum alloy according to any one of the above (1) to (3), has a tensile strength of 400 MPa or more, and a 0.2% yield strength of 375 MPa. Thus, the elongation at break is 10% or more.

  The aluminum alloy member of the embodiment has a tensile strength and 0.2% proof stress equivalent to or higher than A6056, and is excellent in strength and proof stress as well as elongation. Examples of such an aluminum alloy member include a bolt, a spool valve, and a crank. As described above, depending on the composition, the tensile strength is 410 MPa or more, the 0.2% proof stress is 385 MPa or more, the breaking elongation is 10% or more, the tensile strength is 420 MPa or more, 0.2 The% yield strength is 395 MPa or more, and the elongation at break is 10% or more.

[Details of the embodiment of the present invention]
Hereinafter, an aluminum alloy, an aluminum alloy wire and a manufacturing method thereof, an aluminum alloy member and a manufacturing method thereof according to the embodiment will be described. In the following description, the composition of the aluminum alloy is shown in mass%. In addition, this invention is not limited to these illustrations, is shown by the claim, and is intended that all the changes within the meaning and range equivalent to the claim are included. For example, in the test examples described later, the type, content, solidification rate, Z factor, solution treatment conditions, aging treatment conditions, size (wire diameter), and the like of the additive element can be appropriately changed.

[Aluminum alloy]
<Composition>
The aluminum alloy of the embodiment has a composition (remainder Al and inevitable impurities) in which three elements: Si, Mg, and Fe are essential elements and Cu, Mn, and Cr are not essential elements. Selected from a composition containing Cu in a specific range (particularly a composition containing 0.1% or more (second composition)), a composition containing at least one element of Mn and Cr in a specific range, Ti and Zr A composition containing at least one element in a specific range (third composition) can be used. The total content of additive elements other than the above three essential elements is preferably 0.001% or more and 1.5% or less, and more preferably 1.0% or less. Hereinafter, the content and effect of each element will be described.

-Si: more than 1.0% and 1.5% or less Si dissolves in Al together with Mg by solution treatment, precipitates as fine Mg ₂ Si by aging treatment (artificial aging), and strengthens the aluminum alloy. In addition, Si (excess Si) remaining after the reaction with Mg solidifies in Al, precipitates, or crystallizes in a dendritic form, thereby strengthening the aluminum alloy. On the other hand, when excessive Si is excessive, segregation to the grain boundary becomes excessive and embrittles. By containing Si in excess of 1.0%, the above-described reinforcing effect can be appropriately expressed, and an aluminum alloy wire or aluminum alloy member having a predetermined strength, an aluminum alloy member excellent in strength, etc., preferably proof stress In addition, an aluminum alloy member that is also excellent can be obtained.

  By containing Si in the range of 1.5% or less, grain boundary embrittlement can be suppressed, and high strength and workability can be improved. For example, the workability when performing various plastic workings such as a process from a cast material to a wire, a process from a wire to a bolt, and a process from a cast material to a crank is difficult to be hindered. And by containing Si in the range of 1.5% or less, it is possible to suppress the formation of coarse crystallized substances and precipitates that can be the starting point of cracking during the plastic processing described above. As a result, an aluminum alloy wire excellent in workability can be obtained, or it can contribute to increasing the strength of the aluminum alloy member. The Si content is preferably more than 1.0% and 1.4% or less, and more preferably 1.1% or more and 1.3% or less. When Si is contained in the above range, an aluminum alloy member having excellent mechanical properties can be easily obtained. In addition, when continuous casting is included in the manufacturing process of an aluminum alloy, the solidification rate is high in continuous casting. Therefore, compared with the case where other typical manufacturing methods (for example, billet casting → extrusion) are used, excess Si is used. Is contained in a large amount.

Mg: 0.5% or more and 1.2% or less Mg strengthens the aluminum alloy by solid solution strengthening and forms an aging precipitate that contributes to strength improvement together with Si by performing aging treatment. It is an element that improves strength. An aluminum alloy wire or aluminum alloy member having a predetermined strength that has a sufficient strength improvement effect due to solid solution strengthening or precipitation hardening by containing Mg of 0.5% or more, and further an aluminum alloy member excellent in strength For example, an aluminum alloy member having excellent proof stress can be obtained. However, if Mg is contained excessively, it becomes difficult to obtain the strengthening effect due to the above-described excess Si, the strength and proof stress are reduced, the component is liable to cause macro segregation during casting, and the resistance to stress corrosion cracking is reduced. Or the workability is lowered or the heat resistance is lowered, so that the Mg content is preferably 1.2% or less. The content of Mg is preferably 0.6% or more and 1.1% or less, and more preferably 0.7% or more and 1.0% or less. When Mg is contained in the above range, an aluminum alloy member having excellent mechanical properties and good heat resistance can be easily obtained.

Fe: 0.3% or more and 0.8% or less Fe strengthens the aluminum alloy by solid solution in the matrix. Fe also makes crystal grains finer and makes it easier to work harden an aluminum alloy. As a result, the tensile strength and proof stress increase. Further, by making the crystal grains finer and increasing the amount of grain boundaries, the adverse effects caused by the grain boundary segregation of Si are relatively suppressed, and grain boundary embrittlement is suppressed. Therefore, unlike the conventional 6000 series alloy that reduces Fe as much as possible, the aluminum alloy according to the embodiment is characterized by positively containing Fe, and particularly containing Fe as much or more as Cu. Fe is contained in an amount of 0.3% or more, and in the production process, rapid cooling by continuous casting is used, so that Fe can be sufficiently dissolved even at a high concentration of 0.3% or more, and coarse Al -Formation of Fe crystallized product can be suppressed. By suppressing the formation of coarse Al—Fe crystallized matter, the above-mentioned crystal grain refining effect can be satisfactorily obtained while containing a large amount of Fe of 0.3% or more. By appropriately obtaining the above-mentioned solid solution strengthening effect and crystal grain refining effect, the effect of improving the strength by precipitation hardening of precipitates such as Mg ₂ Si can be obtained satisfactorily.

  By containing Fe in a range of 0.8% or less, Fe-based crystallized substances (Al-Fe-based compounds such as Al-Fe-Si) and precipitates (Al-Fe, etc.) are excessively generated. It can suppress that the plastic workability of an alloy falls. Therefore, plastic work materials such as aluminum alloy wires that are rolled or drawn and aluminum alloy members such as bolts that are subjected to head machining can be manufactured with high productivity. Furthermore, it is possible to obtain an aluminum alloy wire or aluminum alloy member having a predetermined strength, an aluminum alloy member excellent not only in strength but also in yield strength and elongation. In addition, in the case of containing Fe in the above range and containing an element having a crystal refining effect including Ti, in the presence of an alkaline earth metal element (for example, Mg or Sr described later), at the time of casting, Refinement of crystals by the above elements can also be promoted, and a fine crystal structure can be obtained more easily. Since the cast material has a fine crystal structure, workability after casting can be improved, and strength improvement by the fine structure can be expected to some extent. In consideration of workability, the Fe content is preferably 0.7% or less, and more preferably 0.6% or less. When Fe is contained in this range, an aluminum alloy wire or aluminum alloy member can be produced with high productivity, and an aluminum alloy member having excellent strength and proof stress can be easily obtained.

Cu: 0% or more and 0.5% or less In a general conventional 6000 series alloy, Cu precipitates in the matrix as an Al—Cu compound and contributes to improvement in strength. Therefore, some conventional 6000 series alloys contain a relatively large amount of Cu, such as 6056, for example. However, in the aluminum alloy of the embodiment, since the mechanism of alloy strengthening is different from that of the conventional alloy, Cu is not contained (0%), or even when Cu is contained (more than 0% is more than 0.00%). 5% or less). Specifically, the aluminum alloy of the embodiment is characterized in that the Cu content is equal to or less than the Fe content. When Cu is contained (as an example, 0.01% or more), the grain boundary Si and Cu are made of aluminum (main component of the matrix) and atomic arrangement by performing an aging treatment after a solution treatment at a relatively high temperature. Precipitates as a matched compound and hardly causes embrittlement of grain boundaries or does not substantially embrittle. This action can further suppress the adverse effect of segregated Si, which inherently embrittles the grain boundaries, so that when Cu is contained, a structure having higher strength, yield strength, and elongation can be obtained.

  When Cu is contained, the strength increases as the Cu content increases, so 0.01% or more, 0.05% or more, further 0.1% or more, particularly 0.2% or more. Can do. The lower the Cu content, the better the corrosion resistance, heat resistance, and other adverse effects caused by the addition of Cu, such as a decrease in corrosion resistance and a decrease in heat resistance, so the upper limit of Cu is 0.5%. The Cu content can be 0.4% or less. When Cu is contained within the specified range, it is easy to obtain an aluminum alloy member having excellent mechanical properties and excellent heat resistance and corrosion resistance. A part of Cu is allowed to be present as a solid solution. Even when Cu is not contained, it is excellent in corrosion resistance as well as in strength and further in proof stress and elongation due to containing Fe in a specific range as described above and effect of high-temperature solution.

・ Mn: 0% or more and 0.5% or less When Mn is not contained (in the case of 0%), the total content of the additive elements is small, and the deterioration of workability due to the high concentration of the additive elements can be suppressed. Excellent in properties. In this case, since there are few types of melting raw materials at the time of casting, the time required for adjusting the molten metal can be shortened and the productivity is excellent. Furthermore, in this case, since the solidus temperature is lowered, the casting temperature can be lowered. As a result, the temperature rise time to the casting temperature can be shortened and the casting speed can be increased, so that productivity is excellent. On the other hand, when Mn is contained (in the case of more than 0%), a part of Mn is dissolved in the matrix and the aluminum alloy is solid solution strengthened. Further, when Mn is contained, Mn forms Al—Mn-based dispersed particles and suppresses the coarsening of crystal grains constituting the alloy structure. In particular, the dispersed particles suppress the coarsening of crystal grains during heat treatment such as solution treatment and aging treatment, thereby contributing to refinement of the crystal structure, and are effective in improving heat resistance. By miniaturizing the alloy structure, effects such as improvement in strength, improvement in workability, and improvement in corrosion resistance can be expected. Therefore, when Mn is contained, it is easy to obtain an aluminum alloy member that is further excellent in strength and proof stress. In addition, an Al—Fe compound crystallized in a needle shape usually crystallizes spherically in the presence of Mn. Since the crystallized product has a less adverse effect on workability when it is spherical, workability may be improved by containing an appropriate amount of Mn. However, if the content of Mn is too large, coarse crystallized substances and precipitates that can be the starting point of cracking are formed, and this causes a decrease in workability. Further, when Mn increases, the solidus temperature of the molten metal rises, so that it is necessary to raise the casting temperature, leading to a decrease in productivity. Therefore, when it contains Mn, 0.5% or less is preferable, 0.4% or less, Furthermore, 0.3% or less is more preferable.

-Cr: 0% or more and 0.5% or less When Cr is not contained (in the case of 0%), the total content of additive elements is small, and the processability is excellent as described above. Further, in this case, like Mn, the productivity is excellent by shortening the adjustment time of the molten metal and lowering the casting temperature. On the other hand, when Cr is contained (in the case of more than 0%), dispersed particles are formed in the same manner as Mn described above, contributing to the refinement of crystals and improving the strength. Further, Cr has an effect of improving heat resistance and corrosion resistance. Therefore, when Cr is contained, it is easy to obtain an aluminum alloy member that is further excellent in strength and proof stress, and an aluminum alloy member that is also excellent in corrosion resistance. However, when there is too much content of Cr, the coarse crystallized substance and precipitate which may become a crack starting point are formed, and the fall of workability is caused. Further, when Cr is increased, productivity is lowered due to an increase in casting temperature as in Mn. Therefore, when it contains Cr, 0.5% or less is preferable, 0.4% or less, Furthermore, 0.3% or less is more preferable.

-Ti: 0.001% or more and 0.1% or less When Ti is contained, the effect of making the crystal structure of the cast material fine or increasing the ratio of equiaxed crystals by suppressing the ratio of columnar crystals in the cast material Is obtained. As a result, when Ti is contained, the workability when performing plastic processing after casting, for example, rolling, wire drawing, forging, or forming into bolts, can be improved by refining the crystal structure of the cast material. Further, since the crystal structure becomes fine, it is possible to obtain a plastically processed material that hardly causes wrinkles during plastic processing and has few wrinkles and excellent surface properties. Furthermore, since the crystal structure is fine, an improvement in strength and proof stress can be expected. By containing 0.001% or more of Ti, the above-mentioned refinement effect and the effect resulting from this effect are appropriately obtained. The larger the Ti content, the more the above-mentioned miniaturization effect. However, if the Ti content is too large, the workability and productivity may be reduced due to the increase in additive elements, so the Ti content is preferably 0.1% or less. A more preferable Ti content is 0.01% or more and 0.05% or less. In addition to Ti alone, a compound such as TiB ₂ or an alloy such as Al—Ti—B can be used for addition of Ti. B, like Ti, has an effect of improving the strength by making the crystal structure fine. Therefore, in the aluminum alloy of the embodiment, the content of B of about 50 ppm or less is allowed by mass ratio.

-Zr: 0.05% or more and 0.2% or less When Zr is contained, heat resistance can be improved. Further, when Zr is contained, similarly to Mn, dispersed particles containing Zr are formed, and the coarsening of the crystal grains during the heat treatment described above is suppressed, thereby contributing to the refinement of the crystal structure. As a result, the effect of improving the strength and the effect of improving the workability associated with the fine crystal structure can be expected. By containing 0.05% or more of Zr, the effect of improving the heat resistance and the effect of improving the strength and workability due to the above-mentioned miniaturization can be obtained appropriately. When the content of Zr is 0.2% or less, it is possible to suppress a decrease in workability due to the formation of coarse crystallized substances and precipitates. When Zr is increased, the productivity is lowered due to an increase in casting temperature as in Mn and Cr. A more preferable content of Zr is 0.1% or more and 0.2% or less. When Zr is not contained, the total content of additive elements is small, and the processability is excellent as described above. Further, in this case, like Mn and Cr, the productivity is excellent by shortening the adjustment time of the molten metal and lowering the casting temperature.

-Other elements In addition, Sr can be contained. Sr has the effect of refining the crystal structure of the cast material. In particular, when Sr is contained in the presence of Si, the crystallized size of Si can be reduced, and plastic workability such as rolling can be improved. The content of Sr is preferably 0.005% or more and 0.05% or less, and more preferably 0.005% or more and 0.03% or less.

  In addition, Zn can be contained. When Zn is contained, Zn is precipitated as an Al—Zn compound, and a strengthening effect by precipitation hardening is obtained. In order to obtain this effect, the Zn content is preferably 0.005% or more. Excessive Zn content causes a decrease in corrosion resistance and heat resistance, so the Zn content is preferably 0.25% or less. A more preferable Zn content is 0.05% or more and 0.2% or less. When Zn is not contained, the total content of the additive elements is small, and the processability is excellent as described above, and the corrosion resistance and heat resistance are also excellent.

-Fe content (Fe content) ≥ Cu content (Cu content)
When the aluminum alloy of the embodiment contains Cu, Fe is equivalent to Cu (Fe amount = Cu amount), preferably more than Cu (Fe amount> Cu amount, Cu amount includes zero). By doing so, the effect of hardening by solid solution of Fe appears more strongly than the effect of adding aluminum to soften the aluminum alloy, and the proof stress can be particularly enhanced. The amount of Fe and the amount of Cu can be any amount within the above range and satisfying the amount of Fe ≧≧ Cu.

(Excess Si amount) / (Fe amount): 0.1 or more and 3.0 or less In the aluminum alloy of the embodiment, as described above, a part of Si is dissolved in Al together with Mg by solution treatment, and artificial The aluminum alloy is strengthened by precipitating as fine Mg ₂ Si by aging and solid-solving, precipitating, and crystallizing the remainder of Si (excess Si represented by the above-mentioned <Formula 1>). However, when there is too much excess Si amount, segregated Si to a grain boundary will become excessive and it will embrittle. On the other hand, Fe that refines crystal grains has an effect of relatively reducing the influence of segregation of Si by increasing the amount of crystal grain boundaries. Therefore, if the Fe is sufficiently contained as described above and the excess Si amount is within a certain range, excessive grain boundary segregation of Si can be suppressed. Therefore, in the aluminum alloy of the embodiment, (excess Si amount) / (Fe amount) = [Si content − {(Mg content) / (24.3 × 2)} × 28.1] / (Fe Amount). When (excess Si amount) / (Fe amount) is 0.1 or more, since the excess Si is sufficiently present, the strength can be improved by crystal precipitation or solid solution of Si. An aluminum alloy member having high proof stress can be obtained. When (excess Si amount) / (Fe amount) is 3.0 or less, the adverse effect due to grain boundary segregation of Si is sufficiently suppressed by the effect of refinement of Fe, and the decrease in strength due to segregation of Si is suppressed. it can. As a result, an aluminum alloy member having excellent strength and further excellent yield strength can be obtained. Furthermore, an aluminum alloy member having excellent elongation can be obtained. (Excess Si amount) / (Fe amount) is preferably 0.2 or more and 2.0 or less, and more preferably 0.3 or more and 1.7 or less.

<Organization>
The aluminum alloy according to the embodiment typically has a structure in which a material subjected to continuous casting is subjected to a solution treatment and an aging treatment, and various dispersed particles (mainly crystallized substances and precipitates) are dispersed. In the aluminum alloy of the embodiment, there are a certain amount of dispersed particles of a certain size, that is, a relatively large number of dispersed particles compared to an aluminum alloy having a general dispersion strengthened structure such as Mg ₂ Si. Allow to exist. Here, coarse dispersed particles, for example, dispersed particles having a diameter of 0.1 μm or more, further 0.3 μm or more, particularly 1 μm or more, themselves become a concentration point of stress or a starting point of fracture, and decrease strength and elongation. The aluminum alloy of the embodiment has a large amount of solid solution of components such as Fe as described above, the embrittlement of grain boundaries is suppressed, and the crystal grain size is also small. Therefore, it is considered that the aluminum alloy of the embodiment can have high mechanical properties such as high strength and high toughness even if the coarse dispersed particles as described above are present to some extent. For example, as an allowable amount of coarse dispersed particles in the aluminum alloy of the embodiment, the number of dispersed particles existing in the cross section and having a diameter of 0.3 μm or more (hereinafter referred to as coarse particles) is 0.01 mm. It is mentioned that it is 3000 or less per ² . Preferably, the number of coarse particles is 1000 or less / 0.01 mm ² . Furthermore, in the aluminum alloy of the embodiment, it is preferable that the diameter of the dispersed particles existing in the cross section satisfy approximately 10 μm or less. The diameter of the dispersed particles is defined as the diameter of a circle having an area equivalent to the area of the dispersed particles, that is, the diameter of the equivalent area circle, by extracting the dispersed particles existing in the cross section. The definition of “approximately 10 μm or less” is as follows. Take a cross section of the aluminum alloy to be measured, and observe an area of 100 μm × 100 μm or more in this cross section with a scanning electron microscope (SEM), and disperse all the dispersed particles having a diameter of 0.1 μm or more present in this observation area. Extract. When the extracted particles are counted in order from the particle having the largest diameter, when the size of the extracted particle, which is 5% from the top, is 10 μm or less, “approximately 10 μm or less” is satisfied. For example, a cross section of an aluminum alloy to be measured is taken, and a 200 μm × 200 μm region in this cross section is observed by SEM to extract dispersed particles having a diameter of 0.1 μm or more, and 1000 dispersed particles having a diameter of 0.1 μm or more are obtained. In the case where the diameter of the 50th largest particle is 10 μm or less, this aluminum alloy satisfies the diameter of the dispersed particles of approximately 10 μm or less. The number of coarse particles having a diameter of 0.3 μm or more is preferably small. However, in the aluminum alloy of the embodiment, for example, the coarse particles are 100 particles / 0.01 mm ² , 120 particles / 0.01 mm ² , and 150 particles. Above / 0.01 mm ² is acceptable. Extraction of dispersed particles, measurement of the diameter of an equivalent area circle, and the like can be easily performed by processing an observation image of an SEM using an image processing apparatus or the like.

<Shape: Aluminum alloy wire, aluminum alloy member, etc.>
The aluminum alloy of the embodiment can take various shapes. A typical example is a shape in which at least one kind of plastic working is performed at least once (one pass). Specifically, a primary processing material such as a rolled material (bar material or plate material), a wire drawing material (aluminum alloy wire of the embodiment), a forging material, that is, another processing (secondary processing, for example, plastic processing, Secondary processing material to which cutting or the like is applied. The secondary processed material is, for example, an aluminum alloy member (aluminum alloy member of the embodiment) such as a bolt obtained by subjecting the wire drawing material to head processing or rolling, or a spool valve obtained by cutting the wire drawing material into a predetermined shape. Can be mentioned. In addition, a forged material (an example of an aluminum alloy member of the embodiment such as a crank) obtained by forging a cast material can be given. Since the aluminum alloy of the embodiment is particularly preferably manufactured through a process including continuous casting described later, it can be suitably used as a material that can take a shape that can be manufactured using a continuous cast material. In the above-described wire drawing material (or drawing material), forging material, etc., a continuous casting material can be used as a raw material.

<Size>
The aluminum alloy of the embodiment can take various sizes. For example, in the aluminum alloy wire of the embodiment, the wire diameter can be selected according to the application. For example, in the case of an aluminum alloy wire for bolts, the wire diameter is about 3 mm to 15 mm, further 13 mm or less, and 12 mm or less. An aluminum alloy wire having such a wire diameter can produce a bolt having a size suitable for fastening an automobile part. For example, in the case of an aluminum alloy wire for a spool valve, the wire diameter is about 3 mm or more and 15 mm or less.

<Mechanical properties>
By performing solution treatment and aging treatment, the aluminum alloy of the embodiment can obtain the strength improvement effect by precipitation hardening as in the case of the conventional 6000 series alloy. In particular, since the aluminum alloy of the embodiment has the above-described specific composition, in particular, after performing a solution treatment under the specific conditions described later, and appropriately performing an aging treatment, the strength comparable to that of A6056, Furthermore, it can have higher strength than A6056, higher proof stress and excellent elongation. That is, as an example of the aluminum alloy of the embodiment, one having high strength, excellent proof stress, and high toughness can be mentioned.

  Specifically, as an example of the aluminum alloy of the embodiment, after performing a solution treatment of 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less, aging treatment of 160 ° C. or more and 180 ° C. or less × 4 hours or more is performed. Examples include a tensile strength after application of 400 MPa or more, a 0.2% proof stress of 375 MPa or more, and a breaking elongation of 10% or more. Depending on the composition, manufacturing conditions, solution treatment conditions, aging treatment conditions, etc., the strength, proof stress, and elongation are superior. In particular, the manufacturing process includes plastic working, and the plastic processing (for example, the aluminum alloy wire according to the embodiment) is compared with the solution treatment described above compared to the casting material or the like not subjected to plastic processing. In addition, the tensile strength after aging treatment, 0.2% proof stress, and elongation at break tend to be high. For example, the tensile strength is 410 MPa or more, the 0.2% proof stress is 385 MPa or more, and the breaking elongation is 10% or more, the tensile strength is 415 MPa or more, the 0.2% proof stress is 390 MPa or more, and the breaking elongation is 12 % Or more, or a tensile strength of 420 MPa or more, a 0.2% yield strength of 395 MPa or more, and a breaking elongation of 13% or more. Thus, after the solution treatment and the aging treatment, the aluminum alloy of the embodiment (for example, the aluminum alloy wire of the embodiment) having high strength, excellent proof stress, and high toughness is subjected to secondary processing (for example, plastic working, cutting, It can be suitably used for a material of an aluminum alloy member (for example, an aluminum alloy member of the embodiment) manufactured by performing a surface treatment such as alumite) and a solution treatment and an aging treatment. The mechanical properties of the aluminum alloy wire are obtained by processing a solution-treated and aging-treated material to prepare a test piece for measurement according to JIS Z 2241 (2011), and using this test piece. It can be measured by a tensile test.

  The aluminum alloy member of the embodiment such as a bolt that is a secondary processed material is a solution treatment of the above-described 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less in the manufacturing process until the final product is obtained, and 160 By performing an aging treatment at a temperature of not less than 180 ° C. and not more than 180 ° C. for 4 hours or more, it has high strength, excellent proof stress, and high toughness. Specifically, as an example of the aluminum alloy member of the embodiment (also an example of the aluminum alloy of the embodiment), the tensile strength is 400 MPa or more, the 0.2% proof stress is 375 MPa or more, and the elongation at break is 10% or more. Things. Depending on the composition, manufacturing conditions (plastic processing conditions, etc.), solution treatment conditions, aging conditions, etc., tensile strength is 410 MPa or more, 0.2% proof stress is 385 MPa or more, and elongation at break is 10% or more In addition, those satisfying at least one of tensile strength of 415 MPa or more, 0.2% proof stress of 390 MPa or more, and breaking elongation of 12% or more, tensile strength of 420 MPa or more, 0.2% proof stress of 395 MPa or more, And those satisfying at least one of elongation at break of 13% or more. The mechanical properties of the bolt can be measured by a tensile test using the bolt as a test piece in accordance with JIS B 1051 (2000).

<Corrosion resistance>
The aluminum alloy of the embodiment does not substantially contain an element that inhibits corrosion resistance, such as Zn, or contains a very small amount (0.25% or less). Therefore, the aluminum alloy of the embodiment, the aluminum alloy wire of the embodiment, and the aluminum alloy member of the embodiment are excellent in corrosion resistance, and can be suitably used for parts used in corrosive environments such as automobile parts and materials thereof. In particular, the aluminum alloy of the embodiment not containing Cu is more excellent in corrosion resistance.

[Production method of aluminum alloy]
The aluminum alloy of the embodiment can be manufactured by a manufacturing method including at least a casting process. In addition to the casting process, the manufacturing method can further include at least one of a processing process for performing plastic processing such as wire drawing and rolling, and a heat treatment process for performing heat treatment on the plastic work material. That is, the aluminum alloy of the embodiment is divided into a casting material, a plastic working material (for example, a rolled material, a wire drawing material, a forging material, etc.) obtained by subjecting at least a part of the casting material to casting, and a casting material. In addition, various existing states can be taken: a heat-treated material obtained by heat-treating a plastic-worked material, and a cutting material obtained by cutting one of a cast material, a plastic-worked material, and a heat-treated material. The production process may be selected so that an aluminum alloy in a desired presence state can be obtained.

  In the casting process, it is preferable to use continuous casting. Examples of the heat treatment include intermediate heat treatment applied during plastic working, final heat treatment applied to a plastic material having a final shape, solution treatment, and aging treatment. When manufacturing a secondary processed material such as a bolt, the solution treatment may be performed before or after the secondary processing. When the secondary processing includes a plurality of types of processing, a solution treatment can be performed between a certain processing and another processing. The aging treatment can be performed at any time after the solution treatment. For example, the aging treatment may be performed immediately after the solution treatment, or various processes may be performed between the solution treatment and the aging treatment. The solution treatment is preferably performed under specific conditions described later. In addition, when performing cold plastic working, it is preferable not to perform homogenization after casting until cold working is completed. Hereinafter, the omission of continuous casting, solution treatment, and homogenization will be described first.

<Continuous casting>
Since continuous casting can be rapidly solidified, the generation of crystallized substances can be suppressed and the generation of coarse crystallized substances can be reduced. By reducing the coarse crystallized product, the additive element, particularly Fe, can be sufficiently dissolved by the solution treatment, and the desired precipitate can be formed satisfactorily and uniformly by the subsequent aging treatment. As a result, an effect of improving strength by precipitation hardening can be obtained satisfactorily, and an aluminum alloy member having excellent strength, proof stress, and elongation can be produced. Moreover, the fall of the workability resulting from a coarse crystallization thing can be suppressed. Further, the coarsening of crystal grains can be suppressed by rapid solidification, and a cast material having a fine crystal structure or a cast material having a high ratio of equiaxed crystals per unit cross-sectional area can be obtained. Also from this point, it is possible to suppress a decrease in workability at the time of plastic working performed after casting, and it is possible to manufacture an aluminum alloy having good workability. For continuous casting, a known method such as a belt-and-wheel method or a Properti method can be used.

  Specific control conditions for rapid solidification include, for example, a solidification rate (cooling rate) in the casting process of 1 ° C./second or more. As the solidification rate is increased, generation of crystallized substances can be suppressed, and coarse crystallized substances can be more effectively reduced. The solidification rate can be 2 ° C./second or more, 5 ° C./second or more, 8 ° C./second or more, 10 ° C./second or more. More preferably, the solidification rate is 1 ° C./second or more at an arbitrary position of the molten metal in the cooling process, that is, the entire molten metal is uniformly cooled. By doing so, it is easy to suppress the non-uniformity of the components accompanying the non-uniform solidification state, and plastic processing such as rolling can be satisfactorily performed after casting even if the homogenization treatment is unnecessary. In addition, since the solidification rate is so fast (because of high speed), Fe can be dissolved in supersaturation. Such a solidification rate can be realized, for example, by using a continuous casting machine having a water-cooled copper mold, a forced water-cooling mechanism, or the like. For example, if the mold temperature is lowered, the solidification rate can be increased. Other parameters for adjusting the solidification speed include the size of the cast material (cross-sectional area), the temperature of the molten metal, the casting speed, the amount of coolant, the material and surface roughness of the mold (grooved wheel, belt, dam block, etc.) Can be mentioned.

  By performing rapid solidification by continuous casting, a cast material having a fine crystal structure can be obtained. By using this cast material as the raw material, it is possible to reduce the occurrence of cracks and wrinkles when plastic processing such as rolling, wire drawing, forging, etc. is performed after casting, rolling material, wire drawing material, forging material with excellent surface properties. Etc. are obtained. Furthermore, by using a wiredrawing material with excellent surface properties as the material for secondary processing materials, secondary processing with excellent surface properties can be achieved, even during secondary processing (especially during plastic processing), to reduce the occurrence of cracks and wrinkles. A material is obtained. Therefore, the manufacturing method including the continuous casting process can mass-produce a long cast material having excellent surface properties, and thus, mass production of aluminum alloy wires and the like having excellent surface properties, as well as an aluminum alloy member having excellent strength and proof stress. Can contribute to mass production.

<Solution treatment>
In the solution treatment, the holding temperature is 550 ° C. or higher and 580 ° C. or lower, and the holding time is 15 minutes or longer and 120 minutes or shorter. When the retention temperature of the solution treatment is relatively high at 550 ° C. or higher, the additive element can be sufficiently solid-solved, and the solid solution precipitation state in the vicinity of the crystal grain boundary can be controlled or when Cu is contained. Can precipitate Si and Cu in the above-mentioned specific state, and can prevent embrittlement of grain boundaries. The higher the holding temperature, the more the solid solution of additive elements such as Fe can be promoted, and the adverse effect of the segregation of Si on the grain boundaries can be suppressed. Therefore, the holding temperature is preferably 560 ° C. or higher. If the holding temperature is too high, Si diffusion becomes active and segregation at the grain boundaries is likely. Although the aluminum alloy of the embodiment contains a relatively large amount of Fe and contains an excessive amount of Si and an amount of Fe in a specific ratio, the above-described adverse effects due to the segregation of Si can be reduced, but the segregation of Si is sufficiently suppressed. For this purpose, the holding temperature is preferably 580 ° C. or lower. On the other hand, when the holding time is 15 minutes or longer, the additive element can be sufficiently dissolved. The longer the holding time, the more the solid solution can be promoted, and the time can be 30 minutes or longer. If the holding time is too long, the segregation of Si to the above-described grain boundary proceeds, and it is difficult to suppress the above-mentioned adverse effect even if the crystal grain is refined by Fe or a compound containing Cu and Si is used, and the characteristics are deteriorated. Invite. If the holding time is excessively long, the segregation of Si further proceeds, the melting point in the vicinity of the segregation site is locally lowered, and a part of the alloy is melted, and a granular lump may be formed on the alloy surface (sweating). This is sometimes called a phenomenon) and is liable to cause an appearance defect. Therefore, the solution treatment is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 45 minutes or less.

  The segregation of Si to the grain boundaries starts at about 500 ° C. Therefore, in the temperature range below the 500 ° C. supersolution temperature, only the undesired phenomenon of Si segregation proceeds, but the beneficial phenomenon such as Mg or Si solid solution does not progress. Therefore, in order to produce the aluminum alloy of the embodiment, it is preferable to pass through this temperature range as quickly as possible in the solution treatment step. Specifically, it is preferable that the temperature rising time required from 500 ° C. to the target temperature of the solution treatment is 100 minutes or less. For example, when the target temperature is 570 ° C., the temperature rising time from reaching 500 ° C. to 570 ° C. is set to 100 minutes or less. The temperature raising time is preferably as short as possible, and can be 60 minutes or less, 30 minutes or less, and further 15 minutes or less.

<Omitted homogenization>
The homogenization treatment is typically performed before cold plastic working for the purpose of correcting the non-uniformity of the composition and obtaining a uniform component distribution. As described above, when the solidification rate at the casting stage is sufficiently high, the composition nonuniformity at the casting stage is small, so that the homogenization treatment may not be performed. When performing the homogenization treatment, the holding temperature is preferably 500 ° C. or less and the holding time is preferably 10 hours or less.

[Aluminum alloy wire manufacturing method]
The aluminum alloy wire of the embodiment can be typically manufactured through a casting process, a rolling process, and a wire drawing process. In particular, in the casting process, it is preferable to perform the above-described continuous casting. Therefore, as a manufacturing method suitable for manufacturing the aluminum alloy wire according to the embodiment, the method for manufacturing the aluminum alloy wire according to the embodiment includes a casting process in which continuous casting is performed on the aluminum alloy having the specific composition described above, and the obtained casting material. It is provided with a rolling process for performing a rolling process and a drawing process for performing a drawing process on the obtained rolled material. Details of each step are as follows.

<Casting process>
The casting step is a step of continuously casting the aluminum alloy having the specific composition described above to obtain a cast material. The conditions for continuous casting (method, solidification rate, etc.) are as described in the above section <Continuous casting>.

<Rolling process>
A rolling process is a process of performing a rolling process on the cast material manufactured by the said continuous casting, and obtaining a rolled material. This rolling process is preferably performed hot or warm. Moreover, it is preferable to perform rolling continuously with casting. When rolling is performed continuously with casting, heat rolling or the like can be easily performed using heat accumulated in the casting material, and energy-efficient and mass production of the cast rolling material can be performed. For example, a belt-and-wheel casting machine and a rolling machine connected to the casting machine are used. As such an apparatus, for example, a Properti type continuous casting and rolling mill can be used.

In a rolling process, it is preferable to adjust rolling conditions so that the crystallization thing which may be produced | generated by the said casting process is parted. For example, it is preferable that the Z factor represented by the above-described <Formula 2> Z = ε × exp (Q / RT) is 1.0 × 10 ¹⁰ or more and 1.0 × 10 ¹⁹ or less. By setting the Z factor to 1.0 × 10 ¹⁰ or more, even when a coarse crystallized product (for example, about 10 μm to 50 μm) is generated, it can be divided and refined. Objects can be reduced to approximately 10 μm or less. As a result, it is possible to suppress a decrease in wire drawing workability caused by coarse crystallized substances and a decrease in workability when plastic working is performed on the wire drawing material. Therefore, an aluminum alloy wire can be manufactured satisfactorily. A more preferable range of the Z factor is 1.0 × 10 ¹² or more and 1.0 × 10 ¹⁷ or less. Industrially, the Z factor can be adjusted by the linear velocity during rolling and the rolling temperature (T in <Expression 2>). Although it depends on the size (cross-sectional area) and composition of the object to be rolled, for example, the linear velocity is 5 cm / second or more and 50 cm / second or less, and the rolling temperature is 300 ° C. or more and 550 ° C. or less.

<Wire drawing process>
The wire drawing step is a step of obtaining a wire drawing material by subjecting the rolled material subjected to the above-described rolling processing to wire drawing. The wire drawing is performed until a predetermined wire diameter is obtained. This wire drawing is typically performed cold. Peeling can be performed according to the surface state of the rolled material before wire drawing. Thus, by performing wire drawing after rolling, that is, by performing no homogenization before rolling, or by not performing extrusion (hot) after homogenization, the wire obtained after the wire drawing process The size of the dispersed particles present substantially matches the size of the dispersed particles of the rolled material.

<Other processes related to wire manufacturing>
-WR softening process The raw material (wire rod) after the said rolling process and before the said wire drawing process can be softened. By performing the WR softening treatment, the non-uniform distortion introduced in the rolling process is removed, and a uniform processed structure is easily obtained in the wire drawing process. The conditions of the WR softening treatment are, for example, the atmosphere is a non-oxidizing atmosphere (depressurized atmosphere, inert gas atmosphere, reducing gas atmosphere, etc.) or air atmosphere, the holding temperature is 250 ° C. or higher and 450 ° C. or lower, and the holding time is 1 The time is 48 hours or less.

Intermediate softening treatment An intermediate softening treatment can be performed on the wire in the middle of the wire drawing. By performing the intermediate softening treatment, accumulation of excessive strain in the wire drawing process can be suppressed, and disconnection can be prevented. The conditions of the intermediate softening treatment are, for example, the atmosphere is the above-mentioned non-oxidizing atmosphere or air atmosphere, the holding temperature is 250 ° C. or higher and lower than 500 ° C. (preferably 300 ° C. or higher and 420 ° C. or lower), and the holding time is 0.5 Or more and 40 hours or less (preferably 1 hour or more and 24 hours or less). The conditions may be adjusted so that the strength of the wire material increased by work hardening is not extremely reduced. Known conditions can be used as the conditions for the intermediate softening treatment.

-Final softening treatment Softening treatment can be performed after final wire drawing. The conditions for the final softening treatment include the above-described non-oxidizing atmosphere, a holding temperature of 300 ° C. or more, and a holding time of 1 hour or more. When the final softening treatment is performed, when an aluminum alloy wire is used as a material for an aluminum alloy member such as a bolt, formability at the time of processing such as a bolt can be improved.

-Solution treatment, aging treatment Furthermore, the above-mentioned solution treatment, the above-mentioned solution treatment, and an aging treatment (conditions are mentioned below) can be performed to the drawn material after the final wire drawing. By performing solution treatment and aging treatment, an aluminum alloy wire having high strength and excellent proof stress and high toughness described in the above <Mechanical properties> section can be obtained. In particular, it is expected that an aluminum alloy wire excellent in elongation can be used as a material for a secondary processed material subjected to plastic working.

<Method for producing aluminum alloy member>
The aluminum alloy member of the embodiment typically includes a step of preparing a material made of the aluminum alloy of the embodiment (a material preparation step), a process including a plastic process (secondary process), and a solution treatment. It can manufacture by a manufacturing method provided with the process (processing and heat processing process) which performs a process. This manufacturing method can further comprise a step of applying an aging treatment after the solution treatment (aging step).

<Material preparation process>
Examples of the material include the aluminum alloy wire according to the above-described embodiment and the aluminum alloy wire manufactured by the method for manufacturing the aluminum alloy wire according to the above-described embodiment (hereinafter collectively referred to as the aluminum alloy wire according to the embodiment). Can be used. When the material that has been subjected to plastic processing at least once (one pass) after casting, such as the aluminum alloy wire of the above-described embodiment, the crystal is refined or coarse crystallized matter is generated. Secondary processing (especially plastic processing) is easy to perform because it is reduced or surface defects are reduced. Therefore, the aluminum alloy member can be mass-produced, which is preferable. When the aluminum alloy wire of the embodiment is used as a material, it can be appropriately cut into a predetermined length. In addition, a continuous cast material (cast bar) can be used as a material.

<Processing and heat treatment process>
The order of the said process and the said solution treatment is not ask | required. Either may be the first. When there are a plurality of the above processes, a solution treatment can be sandwiched between one process and another process. In this case, the aging treatment may be after the solution treatment, the solution treatment and the aging treatment are sandwiched between one process and another process, or the solution treatment is performed before the another process, An aging treatment can be performed after the other processing. That is, what is necessary is just to give the said solution treatment to the target object in the process before giving the process containing plastic processing to the said raw material, and manufacturing an aluminum alloy member. For example, when manufacturing a bolt using the aluminum alloy wire of the above-described embodiment as the material, the aluminum alloy wire or the like is subjected to processing including plastic processing to manufacture an aluminum alloy member such as a bolt. The solution treatment is performed on the object in the process. In this case, the object includes a cut piece obtained by cutting the aluminum alloy wire or the like into a predetermined length, a forged piece obtained by performing intermediate forging on the cut piece, a header piece obtained by subjecting the cut piece to header processing, and the cut For example, a bolt material in which a header process and a rolling process are performed on a piece can be given. As described above, it is preferable that a homogenization treatment is not included between the casting step and the solution treatment, since an aluminum alloy member having superior strength and proof stress can be obtained.

Processing The secondary processing can be appropriately selected so that a desired aluminum alloy member can be obtained. For example, when the aluminum alloy member is a bolt, the secondary processing includes plastic processing such as head processing, rolling processing, and forging processing. For example, when the aluminum alloy member is a bicycle crank, plastic working such as forging may be mentioned. Of the secondary processing, examples of processing other than plastic processing include cutting and surface treatment (such as polishing and anodizing). Surface treatment such as buffing or alumite treatment can be performed after cutting. For example, when the aluminum alloy member is a spool valve, a rod-shaped material (for example, the aluminum alloy wire of the embodiment) may be cut into a desired shape. Known conditions can be used as conditions for each plastic working. Even when a continuous cast material is used as a raw material, processing such as cutting and surface treatment can be performed.

-Solution treatment and aging treatment The conditions of the solution treatment (holding temperature, holding time, temperature rising time, etc.) are as described in the above section <Solution Treatment>.

  The conditions for the aging treatment include a holding temperature of 160 ° C. to 180 ° C. and a holding time of 4 hours or more. By setting the holding temperature to 160 ° C. or more and the holding time to 4 hours or more, precipitates are sufficiently precipitated, an effect of improving the strength by precipitation hardening is obtained, and the strength and further the proof stress are easily increased. By setting the holding temperature to 180 ° C. or lower, it is possible to suppress a decrease in strength due to coarsening of precipitates. By performing an aging treatment under the above conditions, an aluminum alloy member having high strength, proof stress, and excellent elongation can be obtained.

If the holding temperature is low in the above range, the longer the holding time (for example, about 8 hours at about 160 ° C., more than 4 hours at about 170 ° C.), the strength improvement effect by precipitation hardening can be obtained. Furthermore, it is easy to increase the proof stress. If the holding temperature is high in the above range (for example, about 180 ° C.), even if the holding time is short, high strength and further high yield strength can be obtained. Moreover, when the holding temperature is high in the above range, the yield strength tends to increase, and when the holding temperature is low, the tensile strength and elongation at break tend to increase. The holding temperature and the holding time can be appropriately selected according to the required characteristics. For example, when an aluminum alloy is used as a raw material for a cast material, workability can be emphasized, and when an aluminum alloy is used as a raw material for a bolt material, proof stress can be emphasized. In particular, when giving priority to yield strength, the aging treatment conditions are preferably a holding temperature of 170 ° C. or higher and a holding time of more than 8 hours. By performing solution treatment and aging treatment under the specific conditions described above, in the typical form of the aluminum alloy wire of the embodiment or the aluminum alloy member of the embodiment, the diameter of the equivalent area circle in the cross section is 0.3 μm or more. The content of certain dispersed particles satisfies 3000 or less / 0.01 mm ² , and the diameter of the dispersed particles in the cross section generally satisfies 10 μm or less.

  Hereinafter, the characteristics and manufacturing conditions of the aluminum alloy will be specifically described with reference to test examples.

[Test Example 1]
Aluminum alloy wires with various compositions were prepared and the mechanical properties were examined. In this test, an aluminum alloy wire is produced by a process of casting → rolling → drawing. Mechanical properties were examined using a heat treated material obtained by subjecting the obtained wire drawing material to solution treatment and aging treatment as a test piece. Table 1 shows the composition of each sample (the content of each element is mass%, the balance Al and inevitable impurities) and the mechanical properties. Excess Si / Fe shown in Table 1 is (excess Si amount) / (Fe amount), and (excess Si amount) is a value obtained by the above-described <Expression 1>.

<Preparation of aluminum alloy wire>
Pure aluminum used as a base is melted (here, 700 ° C. or more and 750 ° C. or less), and the additive element is added to the melt so as to have a predetermined concentration shown in Table 1, and is sufficiently held (here, 3 hours or more) ). The molten aluminum alloy whose components are adjusted is appropriately subjected to a hydrogen gas removal treatment or a foreign matter removal treatment. Using the produced aluminum alloy melt, casting and hot rolling are continuously performed by a Properti type continuous casting and rolling machine equipped with a belt and wheel type continuous casting machine, and a wire rod (here, having a diameter of 9.5 mm) is used. (Continuous cast rolled material). The solidification rate during casting is 5 ° C./second. Here, casting is performed using a water-cooled copper mold so that the solidification rate is 5 ° C./second at an arbitrary position of the molten metal in the cooling process. Here, rolling is performed by adjusting the linear velocity and the rolling temperature so that the Z factor of the rolling process is 1.9 × 10 ¹⁶ . Subsequently, the wire rod is subjected to cold wire drawing to produce a wire drawing material (here, diameter φ4.5 mm). Here, an intermediate softening treatment was performed in the middle of wire drawing (250 ° C. to 450 ° C. × 5 hours). In addition, the composition of the obtained wire drawing material is the same as the composition of Table 1. A known method can be used for the composition analysis of the wire drawing material, for example, an energy dispersive X-ray analyzer or the like.

<Preparation of test piece>
The obtained aluminum alloy wire (the wire drawing material) is subjected to a solution treatment and an aging treatment to produce a heat treatment material. The solution treatment conditions are 570 ° C. × 30 minutes, and the aging treatment conditions are 170 ° C. × 16 hours. Sample No. Since No. 1-106 was cracked during wire drawing, the mechanical properties were not evaluated. In addition, none of the samples subjected to the solution treatment and the aging treatment has been subjected to a homogenization treatment after casting until the solution treatment.

<Evaluation of mechanical properties>
Using the obtained heat treatment material, a test piece was prepared and subjected to a tensile test (room temperature) to evaluate tensile strength (MPa), 0.2% yield strength (MPa), and elongation at break (%). This tensile test is performed according to JIS Z 2241 (2011).

<Discussion>
As shown in Table 1, Si, Mg, and Fe are included in a specific range, (excess Si amount) / (Fe amount) satisfies 0.1 or more and 3.0 or less, and (Fe amount) ≧ (Cu amount) Sample No. 1-1-No. 1-10 has a high strength when subjected to a solution treatment of 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less and then an aging treatment of 160 ° C. or more and 180 ° C. or less × 4 hours or more. I understand that. Here, Sample No. 1-1-No. It can be seen that all of 1-10 are excellent in yield strength and also have high elongation. Specifically, Sample No. 1-1-No. 1-10 satisfies tensile strength of 400 MPa or more, 0.2% proof stress of 375 MPa or more, and elongation at break of 10% or more. In particular, Sample No. with very low Cu content. 1-9 and Sample No. substantially free of Cu. Even if it is 1-10, it turns out that it is high intensity | strength, is excellent also in yield strength, and has high elongation. It can be seen that the second composition containing 0.1% or more of Cu is more excellent in tensile strength, proof stress, and elongation. It can be seen that when at least one of Cu, Mn, Cr, Zr and Ti is contained in addition to Si, Mg and Fe, the strength and further the proof stress can be easily increased.

Sample No. 1-1-No. Each 1-10 heat-treated material (φ4.5 mm) was cross-sectioned, polished, and observed with a scanning electron microscope (SEM). FIG. It is a SEM photograph of 1-1 aluminum alloy (heat treatment material). In FIG. 1, white particles are dispersed particles (crystallized substances, precipitates), and other gray regions are alloy matrices. As shown in FIG. It can be seen that 1-1 aluminum alloy has a relatively large amount of relatively large dispersed particles. Other sample No. 1-2-No. Sample No. 1-10 is also an aluminum alloy (heat treated material). Similar to 1-1, a relatively large amount of relatively large dispersed particles are present. Sample No. 1-1-No. Using the SEM observation image of the cross section 1-10, the size and abundance of the dispersed particles were examined. Specifically, with respect to the SEM observation image of the cross section, the dispersed particles existing in 100 μm × 100 μm (0.01 mm ² ) are extracted, the diameter of the equivalent area circle of each extracted particle is measured, and the particles of 0.1 μm or more Extracted. As a result of examining the number of particles having a diameter of 0.3 μm or more with respect to the extracted dispersed particles, Sample No. 1-1-No. In all of 1-10, the number of dispersed particles having a diameter of 0.3 μm or more was 200 or more and 950 or less / 0.01 mm ² . Further, as a result of examining the number and size of particles having a diameter of 0.1 μm or more, sample No. 1-1-No. In all of 1-10, the diameter of the dispersed particles was approximately 10 μm or less.

  On the other hand, the sample No. 1-101 and the sample No. 1-102, the sample No. 1-105 has a high strength to some extent, but has a low elongation at break. One of the reasons for this result is that the increase in grain boundaries due to Fe refinement effect is insufficient, and the adverse effects due to segregation of Si cannot be sufficiently suppressed, or coarse crystallized substances are present. It may be generated. Sample No. 1-3 and No. 1-8, even if the Si amount itself is large, if the Fe amount is appropriate, the strength is excellent and the elongation is also high. By appropriately adjusting the Fe amount according to the Si amount, the strength, Furthermore, it is considered that mechanical properties such as proof stress and elongation can be improved. Sample No. with too little Si Sample No. 1-103 or too much Mg 1-104 has a low yield strength. As one of the reasons for such a result, it is considered that the strength improvement effect and the proof stress improvement effect due to precipitation or solid solution of Si or Mg were not sufficiently obtained. When there is too much Fe, it turns out that it is inferior to workability and it is easy to produce a fracture | rupture etc. (sample No. 1-106).

  And (Fe amount) ≧ (Cu amount) is not satisfied, that is, (Fe amount) <(Cu amount), and Sample No. containing more Cu than Fe. Although 1-107 is high strength, it turns out that it is inferior in yield strength. From this result, in order to improve the yield strength in addition to the strength, the content of Cu is suppressed (Cu may not be included), Fe is added positively, and Si, Mg, Fe It turns out that it is preferable to make content and (excess Si amount) / (Fe amount) into a specific range.

  From this test result, Si, Mg, and Fe are included in a specific range, (excess Si amount) / (Fe amount) satisfies 0.1 or more and 3.0 or less, and (Fe amount) ≧ (Cu amount). An aluminum alloy having a certain composition is continuously cast, and then appropriately subjected to a solution treatment (plastic processing such as rolling or wire drawing may be interposed before the solution treatment), and further an aging treatment is performed. As a result, it was confirmed that the strength was high, the proof stress was excellent, and the elongation was also excellent. It can be said that such an aluminum alloy can be suitably used for aluminum alloy members such as bolts, spool valves, and cranks. In addition, No. produced in this test. 1-1-No. It can be said that the 1-10 aluminum alloy wire can be suitably used as a material for aluminum alloy members such as bolts and spool valves.

[Test Example 2]
Sample No. 1 of Test Example 1 1-1 aluminum alloy (mass%, Si: 1.2%, Mg: 0.8%, Fe: 0.5%, Cu: 0.3%, (excess Si amount) / (Fe amount) ) = 1.47), an aluminum alloy wire was prepared, and mechanical properties were examined using a heat-treated material subjected to solution treatment and aging treatment under various conditions as a test piece. The results are shown in Tables 2 and 3.

In this test, after producing a wire drawing material (aluminum alloy wire) under the same conditions as in Test Example 1 (solidification rate: 5 ° C./second, Z factor during rolling: 1.9 × 10 ¹⁶ ), solution treatment and An aging treatment is performed, and a test piece used for measurement of mechanical properties is produced in the same manner as in Test Example 1. Then, in the same manner as in Test Example 1, a tensile test (normal temperature) was performed to evaluate tensile strength (MPa), 0.2% yield strength (MPa), and elongation at break (%). Each sample has not been homogenized between casting and the above solution treatment.

  Each sample shown in Table 2 is subjected to solution treatment under the conditions shown in Table 2, and the aging treatment conditions are 170 ° C. × 16 hours. For each sample shown in Table 3, the conditions for the solution treatment are 570 ° C. × 30 minutes, and the aging treatment is performed under the conditions shown in Table 3.

<Discussion>
As shown in Table 2, the sample treatment conditions for the solution treatment were 550 ° C. or more and 580 ° C. or less × 15 minutes or more and 120 minutes or less. 2-1. It can be seen that 2-16 has high strength and excellent proof stress. Sample No. 2-1. Any of 2-16 is excellent in elongation. Specifically, Sample No. 2-1. In all of 2-16, the tensile strength is 410 MPa or more, the 0.2% proof stress is 385 MPa or more, and the breaking elongation is 10% or more. In the solution treatment, when the holding time is too short (here, 10 minutes), the strength is low, and when the holding temperature is low, the proof stress tends to be low (Sample No. 2-101, No. 2-104, No. 2-106, No. 2-108). The reason for this result is thought to be that solid solution was insufficient. On the other hand, even if the holding time is too long (here, 150 minutes, 180 minutes), the strength is low and the proof stress tends to be low (Sample No. 2-102, No. 2-103, No. 2). -105, No. 2-107, No. 2-109). The reason for this result is that the segregation of Si to the grain boundary progresses during the solution treatment, and the amount of segregated Si cannot be made harmless due to the effect of refining crystal grains by Fe or the formation of a compound with Cu. This is thought to be due to reaching the amount and causing embrittlement. Furthermore, these samples with too long holding times had granular lumps on the alloy surface and poor appearance.

  As shown in Table 3, the sample No. 5 was subjected to aging treatment conditions of 160 ° C. or higher and 180 ° C. or lower × 4 hours or longer. 2-21-No. It can be seen that 2-29 has high strength and excellent proof stress. Furthermore, sample no. 2-21-No. 2-29 is excellent in elongation. Here, Sample No. 2-21-No. As for 2-29, tensile strength is 410 MPa or more, 0.2% yield strength is 385 MPa or more, and elongation at break is 10% or more. In addition, as shown in Table 3, by setting the aging treatment conditions at 160 ° C. or more and 180 ° C. or less × 4 hours or more, although the strength is excellent (here, the tensile strength is 410 MPa or more), the proof stress is also improved. It can be said that it is preferable to increase the holding time when the holding temperature is low, specifically, more than 8 hours at 160 ° C. and more than 4 hours at 170 ° C. If the holding time is too long, mechanical properties such as strength tend to be lowered, and productivity is also lowered. Therefore, it can be said that the holding time is preferably 48 hours or shorter, and more preferably 30 hours or shorter.

[Test Example 3]
Sample No. 1 of Test Example 1 1-1 aluminum alloy (mass%, Si: 1.2%, Mg: 0.8%, Fe: 0.5%, Cu: 0.3%, (excess Si amount) / (Fe amount) ) = 1.47) is produced under various casting conditions and rolling conditions, and a heat treatment material subjected to solution treatment and aging treatment under the same conditions as in Test Example 1 is used as a test piece. The characteristics were investigated. The results are shown in Table 4.

  In this test, as in Test Example 1, a wire drawing material (aluminum alloy wire) was manufactured by a process of continuous casting and rolling to wire drawing. Table 4 shows the solidification rate (° C./second) of the casting process for each sample. The solidification speed was changed by adjusting the mold material, casting speed (ton / hour), and the amount of cooling liquid. Table 4 shows the Z factor during rolling for each sample. The Z factor was changed by adjusting at least one of the linear velocity and the rolling temperature. The rolling temperature was adjusted by using an in-line bar cooler or bar heater and adjusting them.

  In this test, sample no. Only 3-2 was subjected to homogenization after rolling (here, a wire rod which is a continuously cast rolled material). Table 4 shows the homogenization conditions. Other samples have not been homogenized after casting until the solution treatment.

  The obtained aluminum alloy wire is subjected to solution treatment (570 ° C. × 30 minutes) and aging treatment (170 ° C. × 16 hours), and a test piece used for measurement of mechanical properties is produced in the same manner as in Test Example 1. . Then, in the same manner as in Test Example 1, a tensile test (normal temperature) was performed to evaluate tensile strength (MPa), 0.2% yield strength (MPa), and elongation at break (%). Sample No. Since No. 3-101 was cracked during wire drawing, Sample No. Since No. 3-103 was cracked during rolling, the mechanical properties were not evaluated.

As shown in Table 4, Sample No. 3-1. 3-3 No. It can be seen that all of 3-15 have high strength and excellent proof stress. Sample No. 3-1, no. 3-3 No. As for 3-15, all are excellent also in elongation. Here, Sample No. 3-1, no. 3-3 No. 3-15 satisfies tensile strength of 410 MPa or more, 0.2% proof stress of 385 MPa or more, and breaking elongation of 10% or more. Such an aluminum alloy (here, an aluminum alloy wire) having high strength, excellent proof stress and high toughness is (1) a solidification rate during continuous casting of 1 ° C./second or more. (2) aluminum alloy In the production of the wire rod, when rolling the cast material, the Z factor at the time of rolling is set to 1.0 × 10 ¹⁰ or more and 1.0 × 10 ¹⁹ or less. (3) Between casting and completion of wire drawing Furthermore, it can be seen that it is preferable not to perform the homogenization treatment between the casting and the solution treatment.

On the other hand, when the solidification rate at the time of casting was slowed (here, 0.5 ° C./second, sample No. 3-101), cracking occurred at the time of wire drawing. One of the reasons for this result is considered to be that a coarse crystallized product was generated due to a slow solidification rate, and this coarse grain became the starting point of cracking. When the Z factor at the time of rolling was too large (here, 1.0 × 10 ²⁰ , sample No. 3-103), cracking occurred during rolling. When the Z factor at the time of rolling is too small (here, 1.9 × 10 ⁹ , Sample No. 3-102), Sample No. 3-1, no. 3-3 No. It can be seen that the strength and proof stress are low compared to 3-15, and the elongation is particularly small. One of the reasons for this result is considered to be that the crystallized product produced during casting could not be sufficiently divided during rolling and there was a coarse crystallized product.

  On the other hand, it can be seen that if homogenization is performed after casting until cold plastic working (here, wire drawing) is completed, the strength and proof stress may be lower than when homogenization is not performed. . As one of the reasons for such a result, Sample No. 3-2 is thought to be because the effect of the homogenization treatment was not substantially obtained because the solidification rate was high and a uniform structure was already formed at the casting stage. In addition, it is considered that Si was segregated at the grain boundaries and embrittled during the homogenization treatment.

  The aluminum alloy of the present invention can be used as a material for various structural members. The aluminum alloy wire of the present invention is an aluminum alloy member which is desired to be lightweight and high strength, such as a crank bolt for automobile parts and bicycle parts, for example, automobile parts, and a crank, etc. Available for material. The aluminum alloy member of the present invention can be used for the bolts, spool valves, cranks and the like. The method for producing an aluminum alloy wire of the present invention can be used for producing an aluminum alloy wire. The manufacturing method of the aluminum alloy member of this invention can be utilized for manufacture of an aluminum alloy member.

Claims (9)

% By mass
Si: more than 1.0% and 1.3% or less,
Mg: 0.5% or more and 1.2% or less,
Fe: 0.3% or more and 0.8% or less,
Cu: 0.1% or more and 0.4% or less,
Mn: 0.2% or more and 0.5% or less,
Cr: more than 0% and 0.3% or less, the balance being Al and inevitable impurities,
The Fe content is not less than the Cu content,
A composition in which (excess Si amount) / (Fe amount) is a ratio of the excess Si content to the Fe content is 0.3 or more and 1.7 or less;
An aluminum alloy comprising a structure in which dispersed particles are dispersed in a cross section, and the number of dispersed particles having an equivalent area circle diameter of 0.3 μm or more is 100 to 1000 μm in a region of 100 μm × 100 μm. 2. The aluminum alloy according to claim 1 , wherein the dispersed particles having a diameter of 0.1 μm or more existing in the region are counted in descending order of the diameter, and the diameter of 5% of the dispersed particles from the top is 10 μm or less. The composition is further in wt%,
The aluminum alloy according to claim 1 or 2 , comprising at least one element selected from Ti: 0.001% to 0.1% and Zr: 0.05% to 0.2%. The aluminum alloy according to any one of claims 1 to 3 , wherein the tensile strength is 400 MPa or more, the 0.2% proof stress is 375 MPa or more, and the elongation at break is 10% or more. An aluminum alloy wire comprising the aluminum alloy according to any one of claims 1 to 4 . The aluminum alloy wire according to claim 5 , wherein the wire diameter is 3 mm or more and 12 mm or less. % By mass
Si: more than 1.0% and 1.3% or less,
Mg: 0.5% or more and 1.2% or less,
Fe: 0.3% or more and 0.8% or less,
Cu: 0.1% or more and 0.4% or less,
Mn: 0.2% or more and 0.5% or less,
Cr: more than 0% and 0.3% or less, the balance being Al and inevitable impurities,
The Fe content is not less than the Cu content,
An aluminum alloy having a composition in which the ratio of excess Si content to the Fe content (excess Si content) / (Fe content) is 0.3 or more and 1.7 or less is continuously cast to obtain a cast material. A casting process to obtain;
A rolling step of rolling the cast material into a rolled material;
A wire drawing step of drawing the rolled material into a wire drawing material having a predetermined wire diameter,
In the casting process, the solidification rate is 1 ° C./second or more,
In the rolling step, aluminum having a linear velocity of 5 cm / second to 50 cm / second, a rolling temperature of 300 ° C. to 550 ° C., and a Z factor during rolling of 1.0 × 10 ^{10 to} 1.0 × 10 ¹⁹ Manufacturing method of alloy wire. The aluminum alloy wire manufactured by the method for manufacturing an aluminum alloy wire according to claim 7 is subjected to processing including plastic processing, and an object in the process of manufacturing an aluminum alloy member is 550 ° C or higher and 580 ° C or lower × The manufacturing method of an aluminum alloy member provided with the process of performing the solution treatment of 15 minutes or more and 120 minutes or less. The aluminum alloy according to any one of claims 1 to 3 ,
The tensile strength is 400 MPa or more,
0.2% proof stress is 375 MPa or more,
An aluminum alloy member having a breaking elongation of 10% or more.