JP2002254143A - Aluminum alloy forging material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy forging material which is produced by performing a direct hot forging of a cast material in which an extrusion process is not applied without performing a homogenized heat treatment and has a mechanical strength and tenacity equal to or higher than that of conventional, and also provide a method for producing the same. SOLUTION: This aluminum alloy forging material is obtained from an aluminum alloy which meets the component specification of JIS6000 series alloys in which a Ti content is regulated to 0.01-0.1 mass% by a continuous casting method including a semi-continuous one, and is characterized in that the average value of dendrite arm spacing calculated by a cross-line method in the central part of cross section is 23 μm or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al alloy forging material capable of obtaining an Al alloy forging material having high average mechanical strength and toughness, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, in a vehicle such as an automobile (hereinafter, simply referred to as "automobile"), aluminum (hereinafter, aluminum is simply referred to as "Al") alloy is used from the viewpoint of weight reduction in response to environmental problems. Is often used. In particular, if an Al alloy is applied to the cushioning member of the vehicle, the weight below the suspension spring of the vehicle, that is, the so-called unsprung weight can be reduced, and the effect of improving the fuel efficiency and running performance of the vehicle becomes remarkable. Al alloys are employed in various cushioning members of automobiles.

[0003] Various cushioning parts for automobiles made of such Al alloys have mechanical strength (tensile strength, etc.), fatigue strength, impact resistance and corrosion resistance equivalent to those made of cast iron. Etc. are required.

[0004] In this case, the cushioning member of an automobile made of the Al alloy generally has a relatively complicated non-axisymmetric shape. For this reason, a buffer member for an automobile made of the Al alloy is a forged material obtained by homogenizing a cast rod formed by casting an Al-Mg-Si alloy without performing extrusion. The current mainstream is to manufacture as a forged product by hot forging. Such an Al alloy forging material is disclosed, for example, in the publications (1) to (4) outlined below. These publications propose various forged Al alloy forging materials which are improved for the purpose of further improving the mechanical strength, toughness, etc., of a shock absorbing member of an automobile manufactured by hot forging a cast rod without performing extrusion. ing.

(1) JP-A-8-3675 discloses that
i: 0.6 to 3.0%, Mg: 0.2 to 2.0%, C
u: 0.3 to 1.0%, Ti: 0.01 to 0.1%,
B: 0.0001 to 0.01%, Mn: 0.1 to 0.5
%, Cr: 0.1 to 0.5% and Fe: 0.05 to 0.
An Al alloy containing 5% and designed so that the amount of Mg ₂ Si converted from the alloy design value was 1.5% or more, or 0.5% or more was cast at a cooling rate of 200 ° C./sec or less. Thereafter, an Al alloy forging material constituted by forging at an upsetting ratio of 10 to 50% is disclosed.

(2) JP-A-6-256880 discloses that Mg: 0.8-1.2 wt%, Si: 0.7-1.
0 wt%, Cu: 0.3-0.6 wt%, Mn: 0.1
5 wt% to 0.3 wt%, and a total of 0.7 wt.
An aluminum alloy forging material containing t% or less and having a dendrite secondary arm spacing (DAS) of 40 μm or less and having an average crystallite size of 8 μm or less is disclosed.

(3) Japanese Patent Application No. 11-224024 discloses that Mg: 0.6-1.6% and Si: 0.6-1.8.
%, Cu: 0.05 to 1.0%, Fe is controlled to 0.03% or less, Mn: 0.15 to 0.6%,
Cr: 0.1 to 0.2%, Zr: one or more of 0.05 to 0.2%, and hydrogen: 0.25 cc
/ 100gAl or less, a material consisting of the balance Al and inevitable impurities is cast at a cooling rate of 10 ° C / sec or more,
After a homogenizing heat treatment at a temperature of 530 to 600 ° C., hot forging is performed to form a forged material, and Mg ₂ Si and Al—Fe—Si— (Mn, Cr, Z) in the Al alloy structure in the forged material are obtained.
An aluminum alloy forging material having a total area ratio of crystallized substances in the r) system of 1.5% or less per unit area is disclosed.

That is, as disclosed in the above (1) to (3),
The conventional method for manufacturing a forged aluminum alloy material is shown in FIG.
As shown in (b), preparing a molten Al alloy in a usual melting method (S 1 _1), followed by continuous casting the molten Al alloy, semi-continuous casting method (DC casting method) among the so-called continuous casting method of the hot top casting method and the like, any of the methods cast while cooling at a cooling rate not in the range defined in the present invention by (S ₁ 2), producing an aluminum alloy ingot a step of, after which the ingot to be subjected to a homogenization heat treatment (S ₁ 3), had been and a step of performing a homogenization of the aluminum alloy crystals. Although not shown in FIG. 3B, the Al alloy forging material (the ingot) is shown in FIG.
Smashed normal fine pores present subjected to forging to form a dense structure (S ₁ 4), further, by performing a T6 treatment (S ₁ 5), so that the aluminum alloy forging is produced (S ₁ 6).

However, in the case of the forged Al alloy material formed without the extrusion process as described in the above (1) to (3), it is necessary to perform a homogenizing heat treatment after the casting, thereby simplifying the working process. There was a problem that it could not be achieved. That is, such a homogenization heat treatment is performed at a temperature of 500 ° C. or more for 2 to 1 hours.
The necessity of heating for 2 hours or more has been one of the factors for increasing the cost of the aluminum alloy forging material.

(4) On the other hand, Japanese Patent Application Laid-Open No. 7-150312 discloses a method of manufacturing a forged Al alloy material in which the homogenizing heat treatment is omitted.
%, Si: 0.6 to 1.5%, Cu: 0.3 to 1.1%
And Ti: 0.005 to 0.1%, B:
One or two of 0.0001 to 0.004%, Mn:
0.2-0.8%, Cr: 0.05-0.3%, Zr:
An Al alloy ingot containing at least one of 0.05 to 0.25% and the remainder consisting of Al and inevitable impurities is subjected to a temperature of 450 to 520 ° C. without performing a homogenizing heat treatment before extrusion. 490-570 ° C
Composed by performing a precipitation treatment for 1 hour or more at a temperature of
An alloy forging material is disclosed.

[0011]

According to the method (4), although the homogenizing heat treatment can be omitted, it is necessary to perform an extrusion process in exchange for the omission of the homogenizing heat treatment. In addition, there is a problem that after the extrusion process, a precipitation treatment performed by heating at 490 to 570 ° C. for 1 hour or more is further required. That is,
In the method (4), the homogenizing heat treatment conventionally performed before the extrusion processing is replaced with a precipitation processing performed after the extrusion processing. For this reason, the production process was not simplified and the production time was not significantly shortened, so that it did not directly contribute to the cost reduction of the Al alloy forging material.

Accordingly, an object of the present invention is to provide a homogenizing heat treatment,
Another object of the present invention is to provide a method for manufacturing an Al alloy forging material that can obtain an Al alloy forging material having mechanical strength and toughness equal to or higher than that of a conventional Al alloy forging material without performing extrusion. Another object of the present invention is to provide an Al alloy having a high average mechanical strength and toughness by optimizing the size of a crystallized product of an Al alloy ingot.
An object of the present invention is to provide an Al alloy forging material from which an alloy forging material can be obtained.

[0013]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned problems, the present inventors have found that in the cooling step included in the ingot forming step performed on the forged aluminum alloy material, It has been found that a portion having a relatively rough tissue appears as a band due to the presence of a portion that progresses relatively rapidly and a portion that progresses relatively slowly. Further, the present inventors have found that the alloy structure is relatively densely formed by rapid solidification in a portion that is relatively rapidly cooled, and the alloy structure is relatively coarse in a portion that is cooled relatively slowly. Was found. And, by controlling the cooling rate, even when hot forging is performed without performing the extrusion processing or the homogenizing heat treatment, the solid solution state and the texture of the crystallized material during the solution treatment after the hot forging are performed. As a result, a method for manufacturing an Al alloy forging material capable of obtaining an Al alloy forging material having mechanical strength and toughness equal to or higher than that of the related art has been found.

The ingot obtained by the above-described method for producing a forged Al alloy has an average dendrite arm spacing (DAS) value of 23 μm calculated using the intersection method.
m and surprisingly, it has been found that by performing the predetermined treatment (forging or T6 treatment) on the ingot, an aluminum alloy forged material equivalent to or higher than the conventional one can be obtained.

That is, according to the first aspect of the present invention, Ti
JIS6 in which the content of is regulated to 0.01 to 0.1% by mass.
Aluminum alloy with the component standard of 000 series alloy,
By casting at a cooling rate of 10 ° C./second or more by a continuous casting method including a semi-continuous casting method to form an ingot, without subjecting the ingot to a heat treatment for homogenization, and without performing extrusion processing, A method for producing an aluminum alloy forging material for obtaining a forging material is provided (claim 1). Here, JIS6000-based alloys include JIS6101 alloy, JIS6003 alloy, JI
S6151 alloy, JIS6061 alloy, JIS6N01
Alloy, JIS6063 alloy and the like.

By controlling the cooling rate in this manner, a crystallized substance produced from a JIS 6000-based aluminum alloy with a restricted Ti content has a predetermined microstructure. Therefore, by performing hot forging as it is, without performing extrusion and homogenizing heat treatment, an Al alloy forged material is obtained that can obtain an Al alloy forged material having mechanical strength and toughness equivalent to or higher than the conventional one. The Rukoto. Further, according to such a manufacturing method, the production cost of the Al alloy forged material can be reduced and the workability can be improved through simplification of the manufacturing process such as the homogenization process.

According to the second aspect of the present invention, JIS 6000 wherein the content of Ti is regulated to 0.01 to 0.1% by mass.
A forged aluminum alloy material manufactured by continuous casting including semi-continuous casting from an aluminum alloy having a component specification of a base alloy, and a dendrite arm spacing (DA) calculated using an intersection line method at the center of the cross section
An aluminum alloy forging material having an average value of S) of 23 μm or less is provided (claim 2).

This forged aluminum alloy material is made of A
(1) An aluminum alloy forging material that can be manufactured by the method for manufacturing an alloy forging material, wherein the average value of the dendrite arm spacing (DAS) value of the ingot calculated using the intersection method is 23 μm or less. is there.

With such a configuration, A having a mechanical strength (tensile strength or the like) and toughness equal to or higher than the conventional ones can be obtained.
An aluminum alloy forging material from which a 1 alloy forging material can be obtained can be provided at a lower cost.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION << Method of manufacturing forged Al alloy material >>
An embodiment of a method for manufacturing an Al alloy forged material according to the present invention will be described in detail with reference to FIG. FIG. 3A shows a flow of a manufacturing process of an example of the forged aluminum alloy material according to the present invention. A according to the present invention
In a method for manufacturing an alloy forged material, a molten aluminum alloy prepared by melting a raw material containing a component amount in a predetermined range is cooled at a predetermined cooling rate to form an ingot. . As a casting method for casting the Al alloy ingot, a so-called continuous casting method such as a continuous casting method, a semi-continuous casting method (DC casting method), and a hot top casting method can be appropriately selected and used.

As shown in FIG.
In the method of manufacturing forged aluminum alloy materials,
In the melting process, the content of elements within the range regulated by the present invention is A
1 alloy melt is prepared (S₀1) Then, the aluminum alloy
Semi-continuous casting (DC casting), hot top
Appropriately selected from so-called continuous casting methods such as casting method
The cooling rate is set at 10 ° C. /
Cast in more than seconds (S ₀2), aluminum having a predetermined shape
Homogenization of ingot by obtaining ingot of aluminum alloy
Without heat treatment and without extrusion
An aluminum alloy forging material will be manufactured.
In addition, it is shown in FIG.
Not dense, but crush fine pores that are normally present
Forging (S₀After performing 5), the T6 processing (S₀6)
To produce aluminum alloy forgings
(S₀7).

(Component content of aluminum alloy forging material) In the method for manufacturing an aluminum alloy forging material according to the present invention,
The Al alloy forging material contains a predetermined amount of a component specified by a JIS 6000 series alloy. In this case, Al
The content of Ti in the alloy forging material is 0.01-0.1% by mass
Is regulated. The reason why JIS 6000-based alloys are used is that they are excellent in corrosion resistance and strength. Also,
The reason for adding Ti is to further improve toughness by adding Ti. Further, the reason for restricting the content of Ti to the above range is that the content of Ti is
If the content is less than 0.01% by mass, the effect of improving toughness is small, while if it exceeds 0.1%, a coarse crystallized substance is formed, so that the toughness is reduced.

(Cooling rate during casting of molten Al alloy) In the method for producing a forged aluminum alloy material according to the present invention, the cooling rate when casting the molten Al alloy is 10 ° C./sec or more. The reason why the cooling rate is set to 10 ° C./sec or more is to refine the crystal grains of the Al alloy ingot to improve the mechanical strength and toughness of the Al alloy forging to be obtained later to a required level or more. That's why. That is, when the cooling rate is less than 10 ° C./sec, the crystal grains of the ingot become coarse,
As described later, the DAS of the Al alloy ingot was 23 μm
This is because it is difficult to set the following, and as a result, it becomes difficult to increase the mechanical strength and toughness of the forged Al alloy to a predetermined strength. The upper limit of the cooling rate in the present invention is within a range in which a systematically sound cast rod can be obtained as is known in the art, and is not particularly limited, but is, for example, 200 ° C./sec.

<< Forged Al Alloy Material >> Next, a forged Al alloy material according to a second embodiment of the present invention will be described. The Al alloy forging material according to the present invention has a high average mechanical strength and a high toughness based on the knowledge of the relationship between the cooling rate during casting and the ingot crystallization described below.
It is characterized in that the size of the crystallized product of the structure of the Al alloy forging material is optimized so that a 1 alloy forging material can be obtained. That is, the forged Al alloy material according to the present invention refers to an ingot having an average DAS value of 23 μm or less at the center of the cross section of the ingot.

First, for the purpose of deepening the understanding of the Al alloy forging material according to the present invention, the details of the cooling step (S ₀₃ ) in the method for manufacturing an Al alloy forging material will be described with reference to FIG. FIGS. 2 (a) and 2 (b) show the process of manufacturing the forged Al alloy material according to the present invention.
The molten alloy is supplied to the mold, a cooling medium is sprayed on the outer peripheral surface of the slab coming out of the mold, and the state corresponding to the change in the amount of heat removed in a series of ingot forming steps of casting at a predetermined cooling rate is shown. FIG. 2 (a) shows a portion (primary cooling section S1) where the mold M and the ingot A immediately after casting come into contact with each other to cool the ingot A, and then the ingot A FIG. 4 is a view schematically showing a surface (secondary cooling unit S2) of which surface is cooled by cooling water CW. As shown in FIG.
After being cooled by contact with the mold M, the cooling water CW is introduced into the surface and cooled. It should be noted that an air gap exists between a portion MC in contact with the mold M and a portion CWC into which the cooling water CW is introduced.

Next, the amount of heat removed from each position of the ingot during the cooling process is schematically shown in FIG. FIG.
FIG. 2B shows a position Z (primary cooling unit S1, secondary cooling unit S2) in the cooling process progress direction of the ingot A shown in FIG. 2A, and a heat removal amount q which is a heat amount taken away by cooling. 6 is a graph showing the relationship of. As shown in FIG. 2 (b), the heat removal q from the ingot A is determined by the mold M and the cooling water C as shown in FIG.
There are formed a portion that changes relatively largely in response to each cooling action of W, and a slow cooling zone in which the amount of heat removal changes relatively small corresponding to a portion near the air gap.

(Crystal of Al alloy) Next, the sectional shape of the ingot obtained after the cooling step will be described with reference to FIGS.
Will be described with reference to FIG. FIG. 1 shows a macrostructure observation photograph of a cross-sectional shape of an ingot after cooling at a cooling rate of 12 ° C./sec in the production of the Al alloy forged material. As shown in FIG. 1, at a depth of about 1/4 from the outer surface to the center of the ingot, DAS was 30 μm.
It can be seen that relatively coarse tissue of about m is distributed in a band shape. In addition, the alloy structure is relatively densely formed in the portion that is cooled relatively rapidly by rapid solidification, and the alloy structure is formed relatively coarsely in the portion that is cooled relatively slowly. The reason that the band distribution appeared was that Al
In the cooling process in the production of forged alloy materials, the part where cooling progresses relatively rapidly and the part that progresses relatively slowly are present in the ingot, so that the part having a relatively coarse structure becomes a band. It is thought to have appeared.

(Reason for setting the average value of DAS to 23 μm or less) Based on the above findings, in the forged Al alloy material according to the present invention, at least 1 mm × the central part of the cross section of the ingot obtained after the cooling step is used. DAS in 1 mm area
The average value is regulated to 23 μm or less. Here, the reason that the measurement area of the DAS was set to the center of the ingot cross section was that sufficient cooling was performed to the center of the ingot, and that the structure was refined, as described above, Another reason is to avoid a relatively coarse structure region having an average DAS value of about 30 μm distributed in a band shape at a depth position of about ４ from the outer surface part of the ingot toward the center part. The reason why the DAS average value was regulated to 23 μm or less was that the DAS average value was 2 μm.
If the thickness exceeds 3 μm, an Al alloy forged material having required mechanical strength and toughness cannot be obtained unless a homogenizing heat treatment is performed thereafter. Further, by configuring the DAS average value to be smaller than 23 μm, a crystallized substance acting to reduce mechanical strength and toughness with respect to the structure of the Al alloy forged material is sufficiently refined. This is because the effect of improving mechanical strength and toughness can be enhanced without performing homogenizing heat treatment or extrusion.

The DAS measurement area must be at least 1 m.
The reason for setting m × 1 mm is to make the area such that at least 200 DASs are included when the DAS is relatively large, about 40 μm.

(Method of Measuring DAS) The evaluation of the characteristics of an Al alloy using such a DAS is performed by comparing DAS which can be directly compared with each other.
It is often difficult to obtain AS. In particular, when Ti is added to an Al alloy, the DAS measurement value tends to fluctuate because the Al alloy crystal becomes finer and the size of the dendrite arm tends to be smaller. It is necessary to evaluate the characteristics of the Al alloy by the method. Therefore, "Measuring method of aluminum dendrite arm spacing and cooling rate" recommended by the Casting and Solidification Subcommittee of the Japan Institute of Light Metals, edited by the Japan Institute of Light Metals, Research Committee, Casting and Solidification Subcommittee, pp. 46-52 (August 1988)
The DAS was measured using the “crossing method” described in “Months”.

The components of the forged Al alloy material according to the present invention,
The content is the same as the content described in the method for manufacturing an aluminum alloy forged material, and therefore the description is omitted here.
Further, it goes without saying that the Al alloy forged material according to the present invention is not manufactured only by the above-described method for manufacturing an Al alloy forged material according to the present invention. Therefore, the Al alloy forging material according to the present invention also includes an Al alloy forging material manufactured by a manufacturing method including a homogenization heat treatment step.

[0032]

Next, embodiments of the present invention will be described in detail. It should be noted that the present invention is not limited to only this embodiment, and can be appropriately modified within the scope of the technical idea of the present invention. Al described in detail below
According to the method for manufacturing an alloy forged material, an Al alloy forged material was produced, and then, the obtained Al alloy forged material was subjected to forging and T6 treatment to produce an Al alloy forged material. Then, a test material (Al alloy forged material) manufactured from an Al alloy forged material falling within the scope of the present invention is used as an example, and a test material (Al alloy forged material not manufactured within the scope of the present invention) ( Al forged material) was used as a comparative example.

Table 1 shows the content of each component of the JIS 6000-based alloy used as a base for producing each of the test materials described above. Table 2 shows the production conditions (cooling rate during casting, measured values of DAS calculated using the intersection method, and Ti content) for the above Examples and Comparative Examples produced from the Al alloys shown in Table 1. Amount), and Charpy impact test (JIS Z2242, test piece shape; J
The impact value according to IS Z2202 No. 3) is shown.

Hereinafter, the method of manufacturing each test material (Example and Comparative Example) will be described in detail with reference to FIGS. 3 (a) and 3 (b). (Examples: Nos. 1, 2, 3, 4) As shown in FIG. 3 (a), as an example, an Al alloy whose element content is within the range regulated by the present invention by a normal melting method. A molten metal is prepared (S ₀ 1), and subsequently, these Al alloy molten metals are subjected to a semi-continuous casting method (DC casting method) to adjust the cooling rate to 12, 15, 20, and 25 ° C./each satisfying the requirements of the present invention. cast and cooled in seconds (S ₀ 2), the diameter was prepared Al alloy forging material of 89 mm.

(Example: No. 5) As shown in FIG.
4 to 4, an Al alloy melt having an element content within the range regulated by the present invention is prepared by a normal melting method (S
₀ 1) Subsequently, these Al alloy melts were cast by a semi-continuous casting method (DC casting method) at a cooling rate of 25 ° C./sec each satisfying the requirements of the present invention (S ₀₂ ). An ingot having a diameter of 89 mm was produced.

(Comparative Examples: Nos. 1, 2, and 3) On the other hand, as a comparative example, as shown in FIG. An Al alloy melt within the range regulated by the formula and an Al alloy melt whose element content is not within the range regulated by the present invention are prepared (S _1).
1) Then, these Al alloy melts are semi-continuously cast (D
C casting method), and cooled at a cooling rate of 6 and 8 ° C./sec, each of which does not satisfy the requirements of the present invention, and cast (S
₁₂ ) A forged Al alloy material having a diameter of 89 mm was produced.

[0037]

[Table 1]

[0038]

[Table 2]

In other words, in Table 1, the content of Si is 0.76 to 0.82% by mass, and the content of Fe is 0.2 to 0.8%.
2 to 0.28 mass%, the content of Cu is 0.23 to 0.2
6% by mass, Mn content is less than 0.01% by mass, Mg content is 0.98 to 1.09% by mass, Cr content is 0.13% by mass, Zn content is 0.01% Less than mass%,
The content of Ti is 0.04 to 0.23% by mass, and the balance is Al
And No. consisting of unavoidable impurities. Examples (Nos. 1, 2, 3, 4, and 5) according to the present invention as shown in Table 2 and comparative examples that do not satisfy the requirements of the present invention using Al alloy test materials 1 to 7 (No. 1, 2, and 3) forged Al alloy materials were produced.

Then, DAS measurement was performed on the forged Al alloy material according to the example manufactured as described above and the forged Al alloy material according to the comparative example.

Further, in the forged Al alloy material (ingot) according to the present invention, fine pores usually present inside the structure of the ingot are crushed at a rolling reduction of 75% to form a dense structure. After forging, a T6 treatment is performed to obtain the A according to the present invention.
Examples manufactured from alloy forged materials (Nos. 1, 2,
3, 4 and 5) and forged Al alloys of Comparative Examples (Nos. 1, 2, and 3).

The aluminum thus produced is
In the longitudinal and width directions of the forged alloy
Cut out test specimens for IS3 impact test
The impact value was measured. At that time, the measurement point of the test piece is
The core was measured, and the measurement points were three in each direction.
The average of the measured values is taken and this average is 16 J / cm ^Two
Passed. Table 2 shows the results.

Reference is made to the impact value of each test piece shown in Table 2.
And the cooling rate during casting (° C./sec), DAS (μ
m) and the Ti content (% by mass) are all essential for the present invention.
In Examples 1, 2, 3, 4, and 5, which satisfy the conditions,
When the value is 16.9 to 25.7 (J / cm ^Two) And relatively
Being an aluminum alloy forging with high mechanical strength
And was confirmed. In particular, it is manufactured from the manufacturing method according to the present invention.
Alloy forging obtained by forging the forged Al alloy forging material
The building materials (Examples 1, 2, 3, 4) were subjected to a homogenizing heat treatment.
Has relatively high mechanical strength despite lack of
It was confirmed that the aluminum alloy was forged.

On the other hand, the cooling rate during casting (° C./sec)
S is not within the range regulated by the present invention (Comparative Example No.
1, 2) or those in which the content of Ti is not within the range regulated by the present invention (Comparative Example No. 7), the impact value is 15.2 to 16. 2
(J / cm ² ) and the examples (No. 1,
2, 3, 4, 5)). In other words, in Comparative Examples (Nos. 1 and 2) in which DAS exceeds 23 μm, the impact value was rejected regardless of the presence or absence of the homogenizing heat treatment. Also,
Even if DAS is 23 μm or less regulated by the present invention, T
In the comparative example (No. 3) in which the i content did not satisfy the 0.01 to 0.1% by mass regulated by the present invention, the impact value was rejected. Comparative examples in which the cooling rate during casting does not satisfy 10 ° C./sec or more regulated by the present invention (No. 1,
In (2) and (3), the DAS exceeded 23 μm, and the impact value was rejected.

As described above, the embodiment (No. 1) is a forged material obtained by forging an Al alloy forged material satisfying the requirements of the invention.
1, 2, 3, 4, and 5) were found to have better impact resistance than Comparative Examples (Nos. 1, 2, and 3) that did not satisfy the requirements of the present invention. Further, the Al according to the present invention
Example (No. 1) is an Al alloy forged material obtained from the Al alloy forged material obtained by the method for manufacturing an alloy forged material.
In 1, 2, 3, 4), without performing homogenizing heat treatment,
It can be said that the average value of the impact value in the longitudinal direction and the width direction of the forged material required for the automobile cushioning member can satisfy the required value.

[0046]

As described above, the present invention has the following effects. According to the method for manufacturing an aluminum alloy forged material according to claim 1, the forged structure is refined, the crystallized material is refined, and the toughness is further improved, and the homogenizing heat treatment and the extrusion process are performed. Hot forging can be performed as it is without performing forging to produce a forged material. According to the aluminum alloy forging material according to claim 2, since the dendrite secondary arm interval (DAS) at the center of the cross section is set to 23 μm or less, the forging structure is refined, the crystallized material is refined, and the toughness is further improved. A further improved aluminum alloy forging can be provided.

[Brief description of the drawings]

FIG. 1 is a macro observation photograph showing a cross section of a forged aluminum alloy material in an example according to the present invention.

FIG. 2 (a) is a view showing a portion (primary cooling portion) of a surface of an aluminum alloy ingot in a state of being cast by a mold M and a surface of the aluminum alloy ingot which is directly cooled by water. FIG. 4 is a diagram schematically showing a part (secondary cooling unit). FIG. 2B is a graph showing the relationship between the position in the direction of progress of the cooling step in FIG. 2A and the heat removal q which is the amount of heat taken.

FIG. 3 (a) is a drawing showing a flow of a manufacturing process of an aluminum alloy forged material according to the present invention. (B) Drawing which shows the flow of the manufacturing process of the conventional aluminum alloy forging material.

[Explanation of symbols]

 A Aluminum alloy ingot CW cooling water M Mold MC Part in contact with mold M CWC Part in which cooling water is introduced S1 Primary cooling part of aluminum alloy ingot A S2 Secondary cooling of aluminum alloy ingot A Department

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Claims (2)

[Claims] 1. The method according to claim 1, wherein the content of Ti is 0.01 to 0.1% by mass.
An ingot is formed by casting an aluminum alloy having a component standard of JIS 6000 alloy regulated in accordance with JIS 6000 at a cooling rate of 10 ° C./sec or more by a continuous casting method including a semi-continuous casting method, and homogenizing the ingot. A method for producing a forged aluminum alloy material, characterized in that a forged material is obtained without heat treatment and without extrusion. 2. The content of Ti is adjusted to 0.01 to 0.1% by mass.
Forged aluminum alloy produced by continuous casting including semi-continuous casting from an aluminum alloy having a component standard of JIS 6000 alloy regulated in Japan, wherein the dendrite arms calculated using the intersection line method at the center of the cross section An aluminum alloy forging material, characterized in that an average pacing value is 23 μm or less.