JP2002348631A - Aluminum-zinc-magnesium aluminum alloy for casting and forging, aluminum-zinc-magnesium cast and forged article, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-Zn-Mg alloy for casting and forging with high strength, advantageous for improving stress corrosion cracking(SCC) resistance and a manufacturing cost, Al-Zn-Mg cast and forged articles, and a method for manufacturing the Al-Zn-Mg articles. SOLUTION: The Al-Zn-Mg alloy for casting and forging superior in casting properties and forging properties includes, by mass%, 3-5% zinc, 1-3% magnesium, 0.20-1.0% copper 0.15-0.30% titanium, 0.10-0.40% zirconium, 0.30% or less silicon, 0.50% or less iron, and the balance aluminum with unavoidable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-zinc-magnesium cast forging forging and forging a cast material having a shape similar to the shape of a final product formed by pouring and solidifying a molten metal. The present invention relates to an aluminum alloy, an aluminum-zinc-magnesium cast forged product, and a method for manufacturing a cast forged product. The present invention can be applied to aluminum alloys that require high strength, high toughness and stress corrosion cracking resistance in addition to weight reduction.

[0002]

2. Description of the Related Art Conventionally, Al-Si-Mg based alloys have been used in a wide range of fields because they have good corrosion resistance, stress corrosion cracking resistance (hereinafter also referred to as SCC resistance) and moderate strength. ing. In this type of alloy, 6061 alloy is a forging alloy and AC4CH is a typical alloy in accordance with JIS as a casting alloy.

However, in the forging alloy described above,
Although it is excellent in strength, elongation and reliability, the material, which is usually an extruded rod, is forged through multiple steps (forged land forging, finish forging, etc.), so the forging cost is high and the final manufacturing cost is inevitable Become higher. Further, since there is a limit to the forming ability of one forging, rough land forging is generally performed a plurality of times until a target similar shape is obtained. Further, the above-mentioned forging alloy has a forging limit, and is not suitable for a thin and complicated shape.

On the other hand, the above-mentioned casting alloy is formed by pouring molten metal into a cavity of a molding die, so that a low-cost, thin and complicated shape can be easily formed, but strength and elongation are not always sufficient. However, there is a problem that the reliability is lower than that of the forging alloy.

[0005] Further, when attempting to forge the above-mentioned casting alloy, forging defects such as forging cracks are liable to occur due to poor plastic workability. Conversely, even if it is attempted to cast using a forging alloy, molten metal flow, shrinkage, casting cracks, etc. are likely to occur,
Poor castability.

Therefore, in recent years, a cast material having a shape similar to the final shape of a product is formed by casting using a molten metal of an aluminum alloy having both castability and forgeability, and forging is performed by forcibly pressing the cast material. By applying, while reducing the number of times of forging in the forging process that induces high cost, it obtains mechanical properties such as tensile strength and elongation comparable to forged products, thereby providing high reliability at lower cost than conventional forged products Al-Si-Mg-based aluminum alloys for casting and forging and methods for producing cast and forged products that have been attempted have been developed (JP-A-5-9637, JP-A-6-73482, JP-A-9-272941).

[0007]

Incidentally, in recent years, further weight reduction and higher strength have been demanded. To meet these needs, the aluminum alloy for casting and forging made of the Al-Si-Mg-based alloy described above is not always sufficient in strength, and further higher strength is required.

[0008] As a high-strength aluminum alloy, Al is used.
-A Zn-Mg based alloy (JIS 7000 based) is known. Forgings of this alloy are used in aircraft parts, etc., but have a problem in stress corrosion cracking resistance (SCC resistance).
The restrictions on use were great.

On the other hand, in the Al alloy according to Japanese Patent Application Laid-Open No. 10-1758, the Al-Zn-M
By subjecting a forged product of a g-based alloy (7050 alloy) to a complicated heat treatment, the SCC resistance is improved. However, since shaping to a shape similar to the minimum product shape is performed not by casting but by cold forging, it has been difficult to obtain a product having a thin and complicated shape at low cost. This is because, in the forging, it is difficult to form a product having a thin and complicated shape due to the limit of forging, and the forging cost is higher than the casting cost.

The present invention has been made in view of the above circumstances, and has a high strength with respect to a conventional Al-Si-Mg alloy (forged product, cast product, cast forged product), and has a high strength. SC resistance, which is a problem of forged Al-Zn-Mg alloys
Al-Zn-M advantageous for improving C properties and manufacturing cost
It is an object of the present invention to provide a method for producing a g-based casting forging alloy, an Al-Zn-Mg based casting forging, and an Al-Zn-Mg based casting forging.

[0011]

An Al-Z according to the first invention is provided.
The alloy for casting and forging of the n-Mg system is, in mass%, zinc: 3 to
5%, magnesium: 1-3%, copper: 0.20-1.0
%, Titanium: 0.15 to 0.30%, zirconium:
0.10 to 0.40%, silicon: 0.30% or less,
Iron: An Al-Zn-Mg-based alloy for casting and forging having excellent castability and forgeability, characterized by 0.50% or less, with the balance being aluminum and unavoidable impurities.

In this case, as an optional component, manganese:
0.20 to 0.70% and chromium: 0.20 to 0.60
%.

According to a second aspect of the present invention, there is provided an Al-Zn-Mg cast forged product, wherein forging is performed by forcibly pressing a cast material formed by casting a molten aluminum alloy for casting forging according to the first or second aspect. It is an Al-Zn-Mg based cast and forged product excellent in castability and forgeability, characterized by being formed by applying. Forging is preferably hot forging, but may be warm forging or cold forging in some cases. Hot forging means forging above the recrystallization temperature.

According to a third aspect of the present invention, there is provided a method for producing an Al-Zn-Mg cast forged product, wherein a molten metal of the aluminum alloy for casting and forging according to claim 1 or 2 is poured into a cavity of a mold. An Al-Zn-Mg based alloy excellent in castability and forgeability characterized by sequentially performing a casting process of forming a casting having a shape similar to a product, and a forging process of forging by forcibly pressing the casting. This is a method for producing a cast forged product. In the casting step, a molten metal is poured into a cavity of a mold and solidified in the cavity to form a cast material having a shape similar to a final product. A mold, a sand mold, or the like can be employed as a molding die.

As described above, since the casting process for forming a cast material having a shape similar to the final product is performed, the conventional rough terrain forging can be eliminated or the number of times of forging can be reduced. As the forging process, hot forging is preferable, but in some cases, warm forging or cold forging may be used. When hot forging,
The temperature of the cast material according to the present invention is equal to or higher than the recrystallization temperature. Generally, it is 380-480 ° C. According to the manufacturing method of the present invention, since the shape of the cast material is similar to the shape of the final product, the number of times of rough land forging in the forging process can be reduced or abolished, which is advantageous in reducing the number of times of forging. .

The Al-Zn-Mg alloy for casting and forging according to the present invention is not Al-Si-Mg alloy but Al-Zn-Mg alloy.
-Mg-based. According to a preferred embodiment of the present invention,
In the forging step, the rolling reduction can be 15% or more. A reduction of 15% or more is effective for improving mechanical properties. In particular, as exemplified in Table 3 below,
It is effective for improving elongation and fatigue strength. The rolling reduction is preferably 30% or more, more preferably 50% or more. If forging cracks and the like can be suppressed during forging, the draft can be further increased.

According to the alloy of the present invention, the cast and forged product of the present invention, and the manufacturing method of the present invention, after the forging step is performed, the alloy and the cast and forged product are heated to a solution heat treatment temperature. After quenching, quenching is performed (generally, quenching to normal temperature), and further aging is preferably performed by heating.
Thereby, the mechanical properties can be further improved. Generally, 440 to 480 ° C. can be adopted as the solution treatment temperature. The aging process may be a one-stage aging process or a two-stage aging process. Alternatively, the composition may be left at room temperature for a long time to age harden.

According to a preferred embodiment of the present invention,
In the case of the two-stage aging treatment, the following can be performed. That is,
After the forging process, after a solution treatment at 440 to 480 ° C., quenching is performed, and then a first aging treatment is performed at a treatment temperature in a range of 100 to 140 ° C., and then a treatment temperature of the first aging treatment is performed. 20 to 50 ° C. higher than 180 ° C.
A form in which the second-stage aging treatment is performed at a temperature not exceeding ℃ can be adopted. In this case, the processing temperature of the second-stage aging treatment is set to a temperature not exceeding 180 ° C. and higher than the processing temperature of the first-stage aging treatment. Above 180 ° C., age hardening is reduced. According to the above, as illustrated in FIG. 5, the aging treatment can be performed in a short time while securing the aging hardness. Depending on the composition, size and shape of the alloy, 44
The time for the solution treatment at 0 to 480 ° C is 0.5 to 3 times.
0 hours can be exemplified, and the time of the first stage aging treatment is 3 hours.
For example, the time for the second-stage aging treatment may be 3 to 48 hours. Al-Zn according to the present invention
-The reason for limiting the composition of the Mg-based alloy for casting and forging will be described.

Zn: 3 to 5% Zn is effective for improving mechanical properties. When Zn is insufficient, mechanical properties are insufficient. When Zn is excessive,
Casting cracks and the like are likely to occur, and castability, forgeability, stress corrosion cracking resistance, and elongation are reduced. Therefore, Zn is set to 3 to 5%. Zn can be preferably used in an amount of 3.5 to 4.5%, and more preferably 3.7 to 4.2%. In consideration of the above circumstances, 3.2%, 3.4%, etc. can be adopted as the lower limit of Zn within the above range, and the upper limit of Zn corresponding to the lower limit is 4.8%, 4. 5% etc. can be adopted. In this specification,% is% by mass unless otherwise specified.
(=% By weight).

Mg: 1-3% Mg is effective for improving mechanical properties. When Mg is insufficient, mechanical properties are insufficient. If Mg is excessive, castability, forgeability, stress corrosion cracking resistance, and elongation decrease. Therefore, Mg is set to 1 to 3%. Mg reduces the extrudability of the alloy, so when solidifying the molten metal and forming a billet material → extruding the billet material → forging the extruded material,
Mg is preferably reduced. However, in the alloy of the present invention, a molten aluminum alloy is cast, a cast material similar to the final shape is directly obtained, and the cast material is strongly pressed and forged. Therefore, there is no restriction on the extrudability, and it is not necessary to reduce Mg due to the restriction on the extrudability. Therefore, Mg is ensured at the above content. Considering the above circumstances, Mg is preferably 1.8 to 2.5%, more preferably 2.0 to 2.5%.
2.3% can be adopted. In consideration of the above-mentioned circumstances, the lower limit of Mg is 1.2% within the above range.
5% or the like can be adopted, and 2.8%, 2.6% or the like can be adopted as the upper limit of Mg corresponding to the lower limit.

Cu: 0.20 to 1.0% Cu is effective in improving mechanical properties and stress corrosion cracking resistance. When Cu is insufficient, the mechanical properties are insufficient,
Insufficient improvement in stress corrosion cracking resistance. If the amount of Cu is excessive, the corrosion resistance and elongation decrease. So Cu is 0.20
1.0%. Cu is preferably from 0.30 to 0.1.
70%, more preferably 0.45 to 0.60% can be adopted. In consideration of the above-described circumstances, the lower limit of Cu can be 0.25%, 0.30%, or the like within the above range, and the upper limit of Cu corresponding to the lower limit is 0.9.
%, 0.8%, etc. can be adopted.

Ti: 0.15 to 0.30% Ti is effective for refining the crystal grains of the solidified structure. If Ti is insufficient, the crystal grains become coarse, cracking during casting,
Rough skin occurs during forging. Even if the amount of Ti is excessive, the effect reaches a plateau, and the insoluble compounds increase to deteriorate the mechanical properties. Therefore, Ti is set to 0.15 to 0.30%. Ti is preferably 0.16 to 0.27%, and 0.1 to 0.27%.
22-0.27% can be adopted. In consideration of the above circumstances, the lower limit of Ti is 0.16% within the above range.
And the like, and the upper limit of Ti corresponding to the lower limit may be 0.28% or the like.

Zr: 0.10 to 0.40% Zr is one of the features of the alloy of the present invention, and is effective in preventing recrystallization during heating such as heat treatment, and furthermore, resistance to stress corrosion cracking and mechanical stress. It is effective to secure the characteristic. It is particularly effective for preventing recrystallization during heat treatment. When Zr is insufficient, when heated in heat treatment or the like, a recrystallized structure is formed, crystal grains are coarsened, and stress corrosion cracking resistance and mechanical properties are deteriorated. When the amount of Zr is excessive, the effect reaches a plateau, and the insoluble compounds increase to deteriorate the mechanical properties. Therefore, Zr is set to 0.10 to 0.40%. Z
r is preferably 0.10 to 0.35%, 0.12 to 0.
35%, 0.17 to 0.25% can be adopted. In consideration of the above circumstances, the lower limit of Zr can be 0.11%, 0.13%, or the like within the above range, and the upper limit of Zr corresponding to the lower limit is 0.39%, 0.38%. % Etc. can be adopted.

Mn: 0.20 to 0.7 as an optional component
0%, Cr: 0.20 to 0.60% 1 or 2 types Mn and Cr are optional components in the alloy according to the present invention, and are effective in preventing recrystallization during heating such as heat treatment. Further, it is effective for improving stress corrosion cracking resistance and mechanical properties. If the amount of Mn or Cr is excessive, the effect reaches a plateau, and the amount of insoluble compounds increases, and the mechanical properties may deteriorate. Preferably Mn is 0.25 to 0.5
5%, 0.25 to 0.45% can be adopted, and Cr is 0.2%.
5 to 0.50% and 0.25 to 0.40% can be adopted.
Note that Mn and Cr may each be contained alone or both may be contained.

Si: 0.30% or less, Fe: 0.50
% Or less Si and Fe are impurities that are easily mixed in the process of refining and casting aluminum, and when the content is large, the mechanical properties are deteriorated. Preferably, Si is 0.25% or less, 0.1% or less.
0% or less is preferable, and Fe is 0.35% or less, and 0.25% or less.
% Or less is preferable.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described together with comparative examples with reference to the drawings.

(Embodiment 1) Influence of Chemical Components Aluminum alloys having the chemical components shown in Table 1 were melted at a melting temperature of 750 ° C. The molten metal is used as a mold test piece mold (J
(The mold temperature was 150 ° C. with ISH5202) and solidified to obtain a cast material. Table 1 also shows the range of chemical components of 6061 alloy (JIS), which is a typical forging material. As can be seen from Table 1, the comparative alloy N
o. 1 to No. 5 is similar in composition to the alloy of the present invention, but has a lower Zr content than the alloy of the present invention.

From the obtained cast material, a test piece having a rectangular cross section of 19.7 mm in width and 24.3 mm in thickness and having a length of 88 mm in length was cut out to obtain forging with 30% reduction in forging. For the cut material, a forging die (upper die 100, lower die 120, forged cavity 1) having the shape shown in FIGS.
At 30), a strong forging was performed under strong pressure to obtain a forged material. In this case, immediately before hot forging, the cut material to be hot forged was heated to a hot state (about 430 ° C.). The forging temperature of the cut material was about 400 ° C., and the die temperature of the forging die was about 200 ° C.
The rolling reduction (%) is defined by [1− (thickness after forging / thickness before forging) × 100].

The above forged material was heated and held at 450 ° C. for 6 hours in an air atmosphere to perform a solution treatment. Thereafter, the forged material was quenched with hot water of 80 ° C. Next, an artificial aging treatment was performed. That is, at 120 ° C. as 24
Heating was performed for 24 hours at 150 ° C. (30 ° C. higher than the temperature of the first aging treatment) as a second aging treatment.

From the forged material subjected to the heat treatment as described above, a tensile test piece 200 having the shape shown in FIG.
(A) SCC test pieces 300 having the shapes shown in (B) were collected. Then, a tensile test was performed on the tensile test piece 200, and a stress corrosion cracking test (SCC test) was performed on the SCC test piece 300. SCC test piece 30
The sample No. 0 was taken in a direction in which the test portion was located on the parting line of the forged material and the test stress was applied perpendicularly to the metal flow so as to increase the SCC sensitivity. In the above-described SCC test, a tensile stress of about 250 MPa is applied to the test portion surface of the SCC test piece 300 by bending by bolting, and the SC
C test piece 300 was immersed in a boiling chromic acid aqueous solution, and the time until crack generation was measured. For the aqueous boiling chromic acid solution, the composition was 36 g / liter CrO ₃ -30 g / liter K ₂ Cr ₂ O ₇ -3 g / liter NaCl, and the temperature was 90 ° C. or higher. The reason why the boiling chromic acid aqueous solution was used is that the alloy of the present invention has excellent SCC resistance, so that stress corrosion cracking hardly occurs in a normal corrosive aqueous solution.

Table 2 shows the results of the tensile test and the SCC test described above. Table 2 also shows the test results of A6061FD-T6 (a representative example of 6061) which is a representative forged product in the 6061 series described above.

As shown in Table 2, the mechanical properties such as tensile strength, 0.2% proof stress, and elongation of the alloy N
o. 1 to No. 7 is Comparative Alloy No. 1 to No. There was no big difference from 5.

Regarding the crack initiation time showing SCC resistance, the alloy No. 1 of the present invention was used. 1 to No. No. 7 was 500 minutes or more, and the SCC resistance was excellent. On the other hand, Comparative Alloy No. 1 to No. In No. 5, the time was 20 to 120 minutes, the time until crack generation was short, and the SCC resistance was poor.
Thus, the alloy of the present invention was more excellent in SCC resistance than the comparative alloy.

Further, the alloy No. 1 of the present invention was used. 1 to No. About No. 7, compared with the conventional alloy A6061FD-T6,
Although the elongation and the SCC resistance were almost equal, the tensile strength and the 0.2% proof stress were significantly excellent.

[0035]

[Table 1]

[0036]

[Table 2]

(Embodiment 2) Effect of rolling reduction A cast material was obtained in the same manner as in Embodiment 1 using an aluminum alloy having the chemical composition of No. 1. Further, a cut piece having a rectangular cross section of 19.7 mm width and a length of 88 mm having a thickness set so as to obtain a predetermined rolling reduction was cut out from the obtained cast material. Then, in the same manner as in the first embodiment, the cut piece was heated and strongly forged in a heated state to obtain a forged material. Further, the forged material was subjected to heat treatment (solution treatment, quenching treatment, first-stage aging treatment, second-stage aging treatment) under the same conditions as in the first embodiment.
Thereafter, a tensile test piece 200 having a shape shown in FIG. 2 and a rotating bending fatigue test piece 500 having a shape shown in FIG. 4 were collected. Then, a tensile test was performed on the tensile test piece 200, and a rotary bending fatigue test (10 ⁷ cycles) was performed on the rotary bending fatigue test piece 500.

Table 3 shows the obtained test results. As shown in Table 3, as the rolling reduction in the forging process increased, the tensile strength, elongation, and fatigue strength were improved. Here, with respect to the tensile strength, at a rolling reduction of about 15%, the rolling reduction is 5%.
There is no inferiority to the case of 0%. However, when the rolling reduction in the forging process was increased, the elongation and the fatigue strength were further increased. Therefore, when emphasis is placed on the elongation and fatigue strength of the cast forged product in the present invention, it is effective to increase the rolling reduction in the forging process to 15% or more. In order to ensure excellent fatigue strength of the cast and forged product, the rolling reduction is preferably 30% or more. In order to secure more excellent fatigue strength, the content is preferably 40% or more and 50% or more.

[0039]

[Table 3]

(Embodiment 3) Effect of two-stage aging A forged material was obtained in the same manner as in the first embodiment using an aluminum alloy having the chemical composition of No. 1. After the forged material was held at 450 ° C. for 6 hours for solution treatment, it was quenched with hot water at 80 ° C. to form first to fifth test pieces. Thereafter, the first test piece was subjected to an aging treatment while maintaining the temperature at 120 ° C. About the 2nd test piece, it kept isothermally at 150 degreeC and performed the aging treatment. The third test piece was aged at 170 ° C. while maintaining the same temperature. For the fourth test piece, after performing the first-stage aging treatment at 120 ° C. for 24 hours,
The second-stage aging treatment was carried out while maintaining the temperature at 150 ° C. isothermally. For the fifth test piece, the first-stage aging treatment was performed at 120 ° C.
For 24 hours, and then the second-stage aging treatment is performed for 17 hours.
The test was carried out while maintaining the temperature isothermally at 0 ° C. The above aging treatment was performed in an air atmosphere.

The change in hardness was measured for each of these test pieces. The measurement results are shown as characteristic lines A to E in FIG. As shown by the characteristic line A in FIG. 5, the test piece did not reach the peak hardness even after 100 hours in the one-stage aging at 120 ° C. As shown by the characteristic lines B and C in FIG.
The aging treatment at 0 ° C. and the aging treatment at 170 ° C. reach the peak hardness in a short time, but the hardness itself is not always sufficient, and a sufficiently satisfactory high strength cannot be obtained. On the other hand, when the first-stage aging treatment was performed at 120 ° C. for 24 hours and the second-stage aging treatment was performed at 150 ° C. as the artificial aging treatment, FIG.
As shown by the characteristic line D, a high peak hardness was obtained in a relatively short time. Similarly, as the artificial aging treatment, the first aging treatment is performed at 120 ° C. for 24 hours, and the second aging treatment is performed at 17 ° C.
When performed at 0 ° C., a high peak hardness was obtained in a relatively short time as shown by the characteristic line E in FIG. Generally, since hardness corresponds to mechanical properties, securing hardness leads to securing mechanical properties.

According to the results shown in FIG. 5, when the alloy of the present invention is used, after forging, solution treatment at 440 to 480 ° C., rapid cooling, and then 100 to 140 ° C.
The first-stage aging treatment is performed at a treatment temperature in the range of, and then the second-stage aging treatment is performed at a temperature 20 to 50 ° C. higher than the treatment temperature of the first-stage aging treatment and not exceeding 180 ° C. It can be seen that if performed, it is effective to enhance age hardening.

(Application) FIG. 6 shows an application. In this case, in the casting process, the Al-Zn-
A molten metal of a Mg-based aluminum alloy for casting and forging was used, and the molten metal was poured into a cavity of a molding die (die, sand mold, etc.). The cavity of the mold has a shape similar to the final product, a forged casting. If the molten metal poured into the cavity of the mold solidifies, the cast material 500 is obtained. After the solidification, the casting 500 is released from the mold. Casting material 500
Has a shape similar to the cast and forged product that is the final product. Thereafter, the hot state (generally 380-480)
C), and a forging step of hot forging by forcibly pressing the cast material 500 at a predetermined reduction rate with a forging die is performed to obtain a forged material 600. As the cast material 500 immediately before the forging step, a material having heat immediately after casting may be used, or a material that has been cooled after casting and reheated to a hot state may be used. The forged material 600 has a flash portion 610 around the periphery. Then, the burrs 610 are punched out by a trimming process to obtain a casting and forging 700. According to this application mode, since the cast material 500 has a shape similar to the final product, the wasteland forging process until the target wasteland shape is obtained from the material can be eliminated. Therefore, in this application form, the forging process is performed only once as finish forging, and costly forging cost can be reduced.

The aluminum alloy for casting and forging and the cast and forged product according to the present invention can be applied to parts (for example, vehicle parts) requiring high strength and high toughness in addition to light weight. For example, the present invention can be applied to a suspension arm (upper arm, lower arm, control rod, etc.) of a vehicle, and further can be applied to a knuckle steering, an actuator body, a delivery pipe, and the like.

FIGS. 7 to 11 show each application form. FIG. 7 shows an upper arm for a vehicle. The upper arm has a plurality of arm portions 10, a tubular portion 11 provided at a tip of the arm portion 10, and a mounting portion 12. FIG. 8 shows a lower arm for a vehicle. The lower arm includes a plurality of arm units 20;
A cylindrical portion 21 provided at the tip of the arm portion 20;
With 2. FIG. 9 shows a knuckle steering for a vehicle. The knuckle steering includes a plurality of arm portions 30,
And a tubular portion 31 connecting the arm portion 30. FIG. 10 shows an actuator body for a vehicle. The actuator body is formed by a box-shaped portion 40. FIG. 11 shows a delivery pipe for supplying fuel and the like. The delivery pipe has a pipe part 50 having a central hole 50a. If the aluminum alloy according to the present invention, the cast forged product, and the manufacturing method according to the present invention are applied to each of these parts, in addition to lightness, high strength and high toughness can be achieved, and stress corrosion cracking resistance is further improved. I can make it. It should be noted that the application of the present invention is not limited to the above.

(Other Examples) According to the above-described embodiment, the two-stage aging treatment is performed after forging. However, the present invention is not limited to this. One-stage aging treatment may be performed, or the aging treatment may be performed at room temperature for a long time. And then age-hardened. In addition, the present invention is not limited to the examples described above and shown in the drawings, but can be implemented with appropriate modifications as needed without departing from the gist. The technical idea according to the present invention may be specified by limiting the content of each alloy element described in each table and the physical property values such as mechanical properties of the alloy to the upper limit value and / or the lower limit value in each claim. it can.

(Supplementary Note) The following technical idea can be understood from the present specification and the drawings. [Appendix 1] The tensile strength is 380 MPa or more (or 40
0 MPa or more). A method for producing an aluminum alloy for casting and forging, a casting forging, and a casting forging according to each of the claims or the supplementary items. [Appendix 2] The method for producing an aluminum alloy for casting and forging, a cast forged product, and a cast forged product according to each claim or each additional item, wherein the 0.2% proof stress is 330 MPa or more (or 350 MPa or more). . [Appendix 3] The method for producing an aluminum alloy for casting and forging, a cast forged product, and a cast forged product according to each claim or each additional feature, wherein the elongation is 10% or more.

[0048]

According to the method for producing an aluminum alloy for casting and forging, the casting forging, and the casting forging according to the present invention, not only mechanical properties such as tensile strength, 0.2% proof stress, elongation and the like can be improved, The stress corrosion cracking resistance can also be improved. Also, forging a cast material having a shape similar to the final product. For this reason, it is possible to abolish the rough land forging for forming a rough shaped material similar to the final product by forging, to reduce the number of times of the rough land forging, and to reduce the costly forging cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a forging die, and (A) and (B) are cross-sectional views in different directions.

FIG. 2 is a configuration diagram of a tensile test piece.

FIG. 3 is a configuration diagram of an SCC test piece, and (A) and (B) are external views viewed from different directions.

FIG. 4 is a configuration diagram of a fatigue test piece.

FIG. 5 is a graph showing a result of an aging process.

FIG. 6 is a process diagram schematically showing a process of manufacturing a casting and forging according to an application mode.

FIG. 7 is a perspective view of an upper arm for a vehicle.

FIG. 8 is a perspective view of a lower arm for a vehicle.

FIG. 9 is a perspective view of a knuckle steering for a vehicle.

FIG. 10 is a perspective view of an actuator body for a vehicle.

FIG. 11 is a front view of a delivery pipe for supplying fuel and the like.

[Explanation of symbols]

In the figure, 500 indicates a cast material, 600 indicates a forged material, and 700 indicates a cast and forged product.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) Term (reference) 4E087 AA10 BA04 BA20 BA24 CA11 CB01 DB15 DB24 GA02 HA28 HA31 HA82

Claims (6)

[Claims] 1. In mass%, zinc: 3 to 5%, magnesium: 1 to 3%, copper: 0.20 to 1.0%, titanium: 0.1 to 1.0%.
15 to 0.30%, zirconium: 0.10 to 0.40
%, Silicon: 0.30% or less, iron: 0.50% or less,
An aluminum-zinc-magnesium-based aluminum alloy for casting and forging having excellent castability and forgeability, with the balance being aluminum and unavoidable impurities. 2. The method according to claim 1, wherein manganese is from 0.20 to 0.20.
Aluminum-zinc-magnesium-based aluminum alloy for casting and forging having excellent castability and forgeability, characterized by containing one or two of 0.70% and chromium: 0.20 to 0.60%. . 3. A cast material having a shape similar to that of a final product formed by casting a molten aluminum alloy for casting and forging according to claim 1 or 2, and forged by forcibly pressing the cast material. An aluminum-zinc-magnesium cast and forged product excellent in castability and forgeability. 4. A casting step of pouring a molten metal of the aluminum alloy for casting and forging according to claim 1 or 2 into a cavity of a molding die to form a cast material having a shape similar to a final product. And a forging step of forging the material by forcibly pressing the material in order. A method for producing an aluminum-zinc-magnesium cast forged product excellent in castability and forgeability, characterized in that: 5. The method according to claim 4, wherein, in the forging step, a rolling reduction is 15% or more, and the cast and forged aluminum-zinc-magnesium alloy has excellent castability and forgeability. 6. The method according to claim 4, wherein after the forging step, a solution treatment is performed at 440 to 480 ° C.
After quenching, the first-stage aging treatment is performed at a treatment temperature in the range of 100 to 140 ° C., and then the temperature is 20 to 50 ° C. higher than the treatment temperature of the first-stage aging treatment and does not exceed 180 ° C. A method for producing an aluminum-zinc-magnesium cast forged product excellent in castability and forgeability, wherein a second-stage aging treatment is performed at a temperature.