JPH07242976A - Aluminum alloy for elongation, excellent in heat resistance, and its production - Google Patents

Abstract

PURPOSE:To maintain solid solution strengthening property and precipitation strengthening property and to provide superior heat resistance by specifying respective contents of Cu, Mg, Si, Fe, Ni, and Ti in an Al alloy and also specifying mutual quantitative relationship between Fe and CONSTITUTION:This Al alloy for elongation has a composition consisting of, by weight, 1.5-4.0% Cu, 1.0-2.0% Mg, 0.1-0.7% Si, 0.1-0.7% Fe, 0.5-1.5% Ni, 0.04-0.2% Ti, and the balance Al with inevitable impurities and satisfying the relation in 0.4Fe+0.6Ni<=1.0. If necessary, one or more kinds among 0.1-0.7% Mn, 0.05-0.5% V, and 0.1-0.3% Zr are further incorporated. This Al alloy is cast and worked by conventional methods and subjected to solution heat treatment and then to aging treatment at 180-220 deg.C for 10-30hr. By this method, the Al alloy material for elongation, having >=154N/mm<2> proof stress even at a temp. as high as about 250 deg.C, can be obtained.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in heat resistance and can be used as a material for mechanical parts such as engine parts and compressors in a transportation field such as automobiles, railway vehicles and ships even under a high temperature atmosphere of 200 ° C. or higher. The present invention relates to an wrought aluminum alloy and a method for manufacturing the same.

[0002]

2. Description of the Related Art As an aluminum alloy for wrought having excellent heat resistance, 2218 is specified as specified in the A / A standard.
Alloys, 2219 alloys and 2618 alloys are well known. However, these alloys do not always have sufficient properties in terms of strength at operating temperatures of 150 ° C. or higher. Therefore, an Al—Cu—Mg-based aluminum alloy excellent in heat resistance as disclosed in JP-A No. 1-290741 is proposed.

[0003]

The heat-resistant aluminum alloy proposed above certainly has excellent high-temperature strength characteristics up to about 150 ° C. However, it must be said that this alloy is still insufficient in the situation where the operating temperature rises above 200 ° C. An object of the present invention is to provide a wrought aluminum alloy excellent in high temperature strength even at a use temperature of 200 ° C. or higher, which is higher than before, and a method for producing the same.

[0004]

Means for Solving the Problems The present inventors
Various factors that impede heat resistance to solve the problem
Experiments were repeated. As a result, especially the high temperatures of 2618 alloy
The main cause of the strength decrease in the alloy is F contained in the alloy.
e and Ni are high temperature and coarse Cu₂FeAl₇, Cu ₃Ni
Al₆Form an intermetallic compound such as, and form a solid solution in the Al matrix phase
It was clarified that this is to reduce the Cu concentration. So
The Fe and Ni contents are regulated together with the Fe and N contents.
By specifying the mutual quantitative relationship of i,
The solid solution strengthening ability and precipitation strengthening ability of Cu are maintained,
Superior heat resistance than before at high temperatures of 200 ° C or higher
It came to the obtained alloy. The present invention is based on this finding
It was made.

The first aspect of the present invention is: Cu: 1.5 to 4.0% Mg: 1.0 to 2.0% Si: 0.1 to 0.7% Fe: 0.1 to 0.7% Ni: 0.5 to 1.5% Ti: 0.04 to 0.2%, Fe and Ni have a relationship of 0.4Fe + 0.6Ni ≦ 1.0, and the balance is Al and unavoidable. It is characterized by comprising impurities.

The second aspect of the present invention further comprises: Mn: 0.1-0.7% V: 0.05-0.5% Zr: 0.1-0.3% It is characterized by containing at least one of them. The third aspect of the present invention is to cast an aluminum alloy having the above-mentioned composition by a conventional method, process it, and then subject it to solution treatment,
It is characterized by being manufactured by performing an aging treatment at 80 to 220 ° C. for 20 to 30 hours.

[0007]

Next, the reason for limiting the component composition range of the aluminum alloy in the present invention will be explained. Cu, Mg, S
i: Cu forms a solid solution in the Al matrix phase and has the effect of significantly improving the mechanical strength by solid solution strengthening. Also Cu, M
Since g and Si coexist with each other, Al ₂ Cu,
It contributes to improvement of mechanical strength by precipitation strengthening of Al ₂ CuMg, Mg ₂ Si and the like. Therefore, the content of each element is, by weight%, Cu: 1.5 to 4.0%, Mg: 1.0 to
2.0%, Si: 0.1 to 0.7%. Cu amount less than 1.5%, Mg amount less than 1.0%, Si amount 0.1
If it is less than%, the strength required at a high temperature of 200 ° C. or higher cannot be obtained in any case. On the other hand, if the Cu content exceeds 4.0%, the driving force for precipitation of the Cu-based intermetallic compound becomes excessively large, and the solid solution strengthening ability and precipitation strengthening ability of Cu decrease. Also, the amount of Mg exceeds 2.0%, Si
Even if the amount exceeds 0.7%, the strength improving effect is saturated. A preferable component range is Cu: 2.4 to 3.8.
%, Mg: 1.4 to 1.8%, Si: 0.3 to 0.6%
Is.

Fe, Ni: Fe and Ni disperse and form an intermetallic compound between Al and Al, and in order to improve the high temperature strength of the alloy, Fe is 0.1% or more and Ni is 0.5%. I need. However, if both are excessively contained,
Not only does the intermetallic compound coarsen, but also C
Since u ₂ FeAl ₇ and Cu ₃ NiAl ₆ are formed to reduce the amount of solid-soluted Cu in the Al matrix phase and rather reduce the strength, Fe is 0.7% or less and Ni is 1.5% or less. To do. As a preferable component range, Fe: 0.3 to 0.6
5%, Ni: 0.8-1.3%. In the present invention, not only is Fe and Ni limited to the above, but also the quantitative relationship between Fe and Ni is specified. The quantitative relationship is 0.4Fe + 0.6Ni ≦ 1.0.
If the quantitative relationship between Fe and Ni does not satisfy this formula, sufficient strength at high temperatures cannot be obtained.

Ti: Ti forms an intermetallic compound with Al and contributes to grain refinement. The content of element is T
i: 0.04 to 0.2%. If the Ti content is less than 0.04%, the above effect cannot be sufficiently obtained. However, if the Ti content exceeds 0.2%, a coarse intermetallic compound is formed with Al and the workability and mechanical properties are impaired. A preferable component range is Ti: 0.07 to
It is 0.16%.

Mn, V, Zr: Although the above-mentioned components are essential components of the present invention, Mn, V, Zr may be added if necessary in order to further secure high temperature strength. Any of Mn, V, and Zr forms an intermetallic compound with Al and contributes to grain refinement.
In particular, Zr and V suppress recovery and recrystallization from normal temperature to high temperature range and prevent a decrease in strength. In order to obtain these effects, the content of each element is Mn: 0.1
~ 0.7%, V: 0.05 to 0.5%, Zr: 0.1
It was set to 0.3%. Mn amount is less than 0.1%, V amount is 0.0
If the amount is less than 5% and the Zr amount is less than 0.1%, the above effect cannot be sufficiently obtained. However, the Mn content exceeds 0.7%,
If the V content exceeds 0.5% and the Zr content exceeds 0.3%, a coarse intermetallic compound is formed and workability and mechanical properties are impaired. A preferable component range is Mn: 0.4 to
0.6%, V: 0.2 to 0.4%, Zr: 0.15
It is 0.25%.

The aluminum alloy of the present invention, whose components are defined as described above, can be manufactured according to the conventional manufacturing method of an Al-Cu-Mg alloy. However, solid solution strengthening by Cu,
Precipitation strengthening by Cu, Mg, Si, Al and Fe and A
In order to effectively utilize the dispersion strengthening due to the formation of the intermetallic compound between 1 and Ni, the solution treatment is performed in the temperature range of 5 to 25 ° C. below the solidus temperature, and then 180 to 220 ° C.
It is desirable to perform aging treatment for 20 to 30 hours. The respective lower limit values under the aging treatment conditions are defined because below the above range, an intermetallic compound capable of acting on strengthening is not formed. On the other hand, the respective upper limit values are specified because if the amount exceeds the upper limit, the formed intermetallic compound becomes coarse and it becomes difficult to obtain the strengthening action, and the solid solution strengthening ability of Cu decreases.

[0012]

EXAMPLE After casting 20 alloys (the chemical compositions of which are shown in Table 1) within the compositional range of the present invention, 5
After homogenizing annealing at 40 ℃ for 6 hours, diameter 1 by forging
It was processed into a 6 mm round bar. Then, after solution treatment at 540 ° C., aging treatment was performed at 200 ° C. for 20 hours. A test piece was prepared from the obtained round bar, and it was stored at room temperature, 150 ° C, 200 ° C.
The mechanical properties (proof stress and elongation) at 250C and 250C were investigated. Further, as comparative examples, in particular, deviations from the specified values of the individual amounts of Fe and Ni (Comparative Examples 1, 2, 3, 4), and F
The deviation of the quantitative relationship between e and Ni from the specified value (Comparative Examples 5, 6, 7), and as conventional examples, the conventional material 2218 alloy (Conventional example 1), 2219 alloy (Conventional example 2), 2618
A test piece of alloy (conventional example 3) was also prepared. As is clear from the results of the investigation in Table 2, the alloy of the present invention has superior high temperature strength properties to the conventional materials. In particular, the superiority becomes remarkable as the temperature rises, and the alloy of the present invention has a proof stress equal to or higher than that of the conventional material at 150 ° C., while it is 154 N / mm ² or more at 250 ° C. It is possible to maintain the proof strength that surpasses.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

INDUSTRIAL APPLICABILITY The aluminum alloy of the present invention effectively exhibits the effects of Fe and Ni which contribute to the improvement of high temperature strength, and the effect of C on both solid solution strengthening and precipitation strengthening.
By incorporating u, Mg and Si as precipitation strengthening elements, and Ti having a grain refining effect, and coexisting with Mn, Zr, and V having a high temperature recovery / recrystallization suppressing effect, if necessary. It is characterized by imparting high temperature strength. With such a configuration, 250
It is possible to exhibit a yield strength of 154 N / mm ² or more even at a high temperature of ° C. Therefore, it can be a very suitable material for mechanical parts used in high temperature environments such as automobile engine parts.

Claims (3)

[Claims] 1. By weight%, Cu: 1.5 to 4.0% Mg: 1.0 to 2.0% Si: 0.1 to 0.7% Fe: 0.1 to 0.7% Ni : 0.5 to 1.5% Ti: 0.04 to 0.2%, Fe and Ni have a relationship of 0.4Fe + 0.6Ni ≦ 1.0, and the balance is Al and unavoidable impurities. An wrought aluminum alloy with excellent heat resistance. 2. The aluminum alloy containing the component according to claim 1, further comprising, by weight%, Mn: 0.1 to 0.7% V: 0.05 to 0.5% Zr: 0.1 to 0. An wrought aluminum alloy with excellent heat resistance containing at least one of 3%. 3. An aluminum alloy containing the component according to claim 1 or 2 is cast and processed by a conventional method and then solution heat treated, and then 10 to 3 at 180 to 220 ° C.
A method for producing an wrought aluminum alloy having excellent heat resistance, which comprises performing an aging treatment for 0 hours.