JP2000319743A - Aluminum alloy material with excellent strength at high temperature and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aluminum alloy material with an excellent strength at high temperatures which shows the strength at high temperatures equal to or greater than an original value even after it has been kept for such a long time as 1000 hours in an atmosphere at the high temperature of 150 deg.C, and a production method therefor. SOLUTION: An aluminum cast ingot composed of 3.0 to 4.5 wt.% Cu, 1.0 to 2.5 wt.% Mg, and 0.2 to 1.0 wt.% Mn, and the balance aluminum with inevitable impurities, is given a soaking treatment at a temperature of 480 deg.C for 4 to 12 hours, hot-rolled, given a solution treatment heated at a temperature of 470 to 570 deg.C for 10 to 60 minutes, cold-rolled at a strain of 6 to 35%, and given an aging treatment. Thus, an aluminum alloy material is provided whose strength at room temperature is not greater than 400 N/mm2 and high temperature strength at 150 deg.C is 350 N/mm2 or more when it is heated at 150 deg.C for 1000 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy material used for, for example, a compressor part and an engine part of an air conditioner used in a high temperature atmosphere of 150.degree. The present invention relates to an aluminum alloy material having excellent high-temperature strength (particularly, proof stress) and a method for producing the same.

[0002]

2. Description of the Related Art Compressor parts and engine parts for air conditioners are used in a high-temperature atmosphere of, for example, 150 ° C., and therefore, aluminum alloy materials used for them are required to have excellent high-temperature strength.

Conventionally, aluminum alloys having excellent high-temperature strength include JIS2017 alloy, 2024 alloy, 22
19 alloy and 2618 alloy. Of these alloys, the 2024 alloy is often used after being subjected to T4 treatment or T6 treatment. The 2219 alloy is obtained by adding Zr, V, Mn, and the like, and the 2618 alloy is obtained by adding Ni, Fe, and the like, and the high-temperature strength is increased by performing the T6 treatment.

[0004] All of these have excellent properties such as high initial strength at a temperature of 150 ° C and high temperature strength in an aging treatment for a relatively short time up to about 100 hours.

[0005]

However, in the above-mentioned conventional aluminum alloy material, after about 100 hours at a high temperature of 150 ° C., the high-temperature strength (particularly the proof stress value) is increased.
Gradually decreases, and after about 1000 hours, the decrease in high-temperature strength becomes remarkable. Therefore, when a conventional aluminum alloy material is applied to a compressor component or an engine component of an air conditioner, durability is reduced, which causes performance degradation and the like.

As described above, in the conventional aluminum alloy material, the strength is reduced and the desired strength can be maintained after a long time of about 1000 hours or more in a 150 ° C. temperature atmosphere. Disappears.

The present invention has been made in view of the above problems, and has been developed in a high-temperature atmosphere at 150 ° C.
It is an object of the present invention to provide an aluminum alloy material having excellent high-temperature strength capable of obtaining a high-temperature strength higher than the initial level even after a long time has elapsed, and a method for producing the same.

[0008]

According to the present invention, the aluminum alloy material having excellent high-temperature strength is Cu: 3.0 to 4.5.
Wt.%, Mg: 1.0 to 2.5 wt.%, And Mn: 0.
2 to 1.0% by weight, the balance being composed of aluminum and unavoidable impurities, strained by cold working after solution treatment, and having a proof stress of 400 N at room temperature. / Mm ² or less, the high temperature proof stress at 150 ° C. when heated to 150 ° C. for 1000 hours is 350 N / mm
It is characterized by being ² or more.

[0009] In the aluminum alloy material high-temperature strength is excellent, the high-temperature yield strength is 390 N / mm ² or more, or the room temperature yield strength is preferably 350 N / mm ² or less. Further, the conductivity is preferably 37 to 45% IACS.

Further, the composition of the aluminum alloy material is C
u: 3.5 to 4.5% by weight, Mg: 1.0 to 2.0
% By weight and Mn: 0.4 to 1.0% by weight, or Cu: 3.0 to 3.8% by weight, Mg: 1.5 to 2.5% by weight, and Mn: 0.2 to 0% 0.5% by weight.

The method for producing an aluminum alloy material having excellent high-temperature strength according to the present invention is as follows: Cu: 3.0 to 4.5% by weight; Mg: 1.0 to 2.5% by weight; An aluminum alloy ingot containing 1.0% by weight and the balance consisting of aluminum and unavoidable impurities is 44
A one-stage or two-stage soaking process of heating at a temperature of 0 to 510 ° C. for 2 to 24 hours, a process of hot rolling the ingot after the soaking process, and a process of heating the aluminum alloy material to 470 to 510 ° C.
A solution treatment by heating at a temperature of 10 to 60 minutes, and a solution treatment material of 6 to 35%, preferably 8 to 3%.
It is characterized by having a step of cold working with a strain amount of 5% and a step of aging treatment.

Another method for producing an aluminum alloy material having excellent high-temperature strength according to the present invention is as follows: Cu: 3.5 to 4.5% by weight; Mg: 1.0 to 2.0% by weight; 4
4% by weight of an aluminum alloy ingot having a composition containing aluminum and unavoidable impurities.
A one-stage or two-stage soaking process of heating at a temperature of 40 to 510 ° C. for 2 to 24 hours, a process of hot-rolling the ingot after the soaking process,
A solution treatment by heating at a temperature of 10 ° C. for 10 to 60 minutes; and 5 to 20%, preferably 8 to 1% of the solution treatment material.
It is characterized by having a step of cold working with a strain amount of 5% and a step of aging treatment.

Another method for producing an aluminum alloy material having excellent high-temperature strength according to the present invention is as follows: Cu: 3.0 to 3.8% by weight; Mg: 1.5 to 2.5% by weight; 2
4 to 0.5% by weight, with the balance being aluminum and inevitable impurities.
A one-stage or two-stage soaking process of heating at a temperature of 40 to 510 ° C. for 2 to 24 hours, a process of hot rolling the ingot after the soaking process,
A step of heating at a temperature of 10 ° C. for 10 to 60 minutes to perform a solution treatment, a step of subjecting the solution treated material to a cold working with a strain amount of 10 to 35%, preferably 12 to 30%, and a step of performing an aging treatment. It is characterized by having.

In the method for producing an aluminum alloy material having excellent high-temperature strength, a step of cold working the aluminum alloy material may be provided between the hot rolling step and the solution treatment step.

The aluminum alloy material further comprises:
It may contain at least one element selected from the group consisting of Cr: 0.10% by weight or less, Zr: 0.20% by weight or less, and Ti: 0.05% by weight or less.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present inventors have conducted various experimental studies to develop an aluminum alloy material that can prevent a decrease in high-temperature strength even after being kept in a high-temperature atmosphere for a long time. As a result, while stipulating the composition of the alloy components and optimizing the production conditions, particularly the cold rolling reduction after the solution treatment, even after long-time holding in a high-temperature atmosphere at 150 ° C., excellent results were obtained. It has been found that high-temperature strength can be maintained.

Hereinafter, the method for producing an aluminum alloy material having excellent high-temperature strength in the present invention will be further described.
First, the reason for limiting the aluminum alloy material having excellent high-temperature strength in the present invention will be described.

The composition of the aluminum alloy material in the present invention is based on a JIS 2000 type alloy, and the reason for adding each component and the reason for limiting the composition will be described below.

Cu: 3.0 to 4.5% by weight Cu is an essential component for ensuring the strength of the aluminum alloy material. If the Cu content in the alloy is less than 3.0% by weight, sufficient strength cannot be obtained. On the other hand, when the Cu content exceeds 4.5% by weight, the initial high-temperature strength and the high-temperature strength under the use conditions of about 100 hours at a temperature of 150 ° C. are high, but the use at a temperature of 150 ° C. for 1000 hours Under the conditions, the over-aged state occurs and the high-temperature strength decreases. In addition, casting cracks are likely to occur when an alloy is manufactured, and cracks and the like are likely to occur during hot rolling due to a decrease in initial workability. Therefore, the Cu content in the aluminum alloy material is set to 3.0 to 4.5% by weight.

Mg: 1.0 to 2.5% by weight Mg, like Cu, is an indispensable component for ensuring the high-temperature strength of the aluminum alloy material. Mg in alloy
If the content is less than 1.0% by weight, sufficient strength cannot be obtained. On the other hand, when the Mg content exceeds 2.5% by weight, the initial strength increases, but the strength decreases after a long time in a high-temperature atmosphere. In addition, the initial workability is deteriorated, and cracks and the like are likely to occur during hot rolling. Therefore, the Mg content in the aluminum alloy material is 1.
0 to 2.5% by weight.

Mn: 0.2 to 1.0% by weight Mn is an element necessary for improving high-temperature strength.
If the Mn content in the alloy is less than 0.2% by weight, sufficient high-temperature strength cannot be obtained after a long time of, for example, 1000 hours at a temperature of 150 ° C. on the other hand,
If the Mn content exceeds 1.0% by weight, the effect is saturated, and it becomes impossible to improve the high-temperature strength even if Mn is further contained in the alloy. At high temperature decreases. Therefore, the Mn content in the aluminum alloy material is set to 0.2 to 1.0% by weight.

Cr: 0.10% by weight or less, Zr: 0.2
0 wt% or less, Ti: 0.05 wt% or less Cr, Zr and Ti are elements that have the effect of refining the crystal grains and improving the high-temperature strength. The above elements can be added. When Cr, Zr or Ti is contained in the alloy, the Cr content is 0.10% by weight or less, the Zr content is 0.20% by weight or less, and the Ti content is 0.05% by weight or less. Even if the amount exceeds these upper limits, the effect is saturated, and coarse compounds increase to lower the strength (toughness). Therefore, Cr, Zr or Zr
Is added, the Cr content is 0.10% by weight or less,
The Zr content is 0.20% by weight or less, and the Ti content is 0.0
5% by weight or less.

Inevitable impurities In addition to the above elements, the aluminum alloy material contains Fe, Si, V, Ni and the like as inevitable impurities.
These unavoidable impurities include Fe of 0.4% by weight or less,
0.4% by weight or less of Si, 0.2% by weight or less of V, Ni
Is less than 0.2% by weight, there is no effect on the properties of the aluminum alloy material. Therefore, Fe as inevitable impurities is 0.4% by weight or less, and Si is 0.4% by weight.
Hereinafter, V is preferably 0.2% by weight or less, and Ni is preferably 0.2% by weight or less, and these are desirably as low as possible.

Next, the reason for limiting the proof stress of the aluminum alloy material in the present invention will be described.

Normal temperature proof strength: 400 N / mm ² or less In the aluminum alloy material after aging treatment, when the proof strength exceeds 400 N / mm ² at normal temperature, the workability at the time of punching and the like is reduced, and the shape and dimensional accuracy are reduced. At the same time, tool wear increases. For this reason, room temperature proof strength is 40
0N / mm ² or less, and preferably have not more than 350 N / mm ^2.

High temperature proof strength: heated to 150 ° C. for 1000 hours
If the proof stress at 150 ° C. after the heating is 350 N / mm ² or more , and the proof stress is heated to 150 ° C. for 1000 hours, it is less than 350 N / mm ² at a high temperature of 150 ° C.
High temperature strength when used at high temperatures cannot be secured. Therefore, the yield strength at 0.99 ° C. after heating 1000 hours an aluminum alloy material to 150 ℃ 350N / mm ² or more, preferably 390 N / mm ² or more.

Conductivity after aging treatment: 37 to 45% If the conductivity after aging treatment of an aluminum alloy is less than 37%, a desired strength cannot be obtained. on the other hand,
When the conductivity exceeds 45%, the initial strength is increased, but the strength after a long time at high temperature is decreased. Therefore, in the present invention, the conductivity after the aging treatment is preferably set to 37 to 45%.

Next, the method for producing an aluminum alloy material according to the present invention will be specifically described. In the present invention, the ingot of the aluminum alloy material is heated to 440 to 510 ° C.
After heating at a temperature of 2 to 24 hours, preferably 4 to 12 hours, soaking, hot rolling is performed, and then, if necessary, cold rolling. Then, at 470 to 510 ° C, 10
A solution treatment is performed by heating for up to 60 minutes, then a predetermined strain is applied by cold working, and then an aging treatment is performed. Hereinafter, the conditions of each of the above processes will be described.

Soaking : 2 at 440-510 ° C.
If the temperature of this soaking (homogenizing treatment) is less than 440 ° C. for less than 440 ° C. , preferably for 4 to 12 hours , the solid solution of the added element becomes insufficient, and sufficient precipitation strengthening cannot be performed in the subsequent heat treatment. The desired high-temperature strength cannot be obtained. The temperature of the soaking heat treatment is 51
If the temperature exceeds 0 ° C., burning occurs and rolling becomes difficult. Therefore, it is desirable to perform soaking at a temperature of 440 to 510 ° C.

If the soaking time is less than 2 hours,
As in the case where the processing temperature is lower than the lower limit, the solid solution of the additional element becomes insufficient, the alloy element cannot be homogenized, and sufficient precipitation strengthening cannot be performed in the subsequent heat treatment, so that a desired high-temperature strength is obtained. Can not do. On the other hand, if the soaking time exceeds 24 hours, the effect is saturated and causes an increase in cost. Therefore, the soaking time is 2
It is preferably from 24 to 24 hours, more preferably from 4 to 12 hours. This soaking may be performed in one stage or in two stages.

Solution treatment: at a temperature of 470 to 510 ° C.
A rolled plate obtained by hot rolling for 10 to 60 minutes or a rolled plate which has been cold-worked to a predetermined thickness after hot rolling is heated and solution-treated. When the temperature of the solution treatment is less than 470 ° C,
Since the solid solution of the additive element becomes insufficient and sufficient precipitation strengthening cannot be performed in subsequent heating, a desired high-temperature strength cannot be obtained. On the other hand, if the temperature of the solution treatment exceeds 510 ° C., burning occurs, and it cannot be used as a product. Therefore, the solution treatment temperature is: 470 to 510 ° C.

On the other hand, if the solution treatment time is less than 10 minutes, the solid solution of the added element becomes insufficient, and sufficient precipitation strengthening cannot be performed in subsequent heating, so that a desired high-temperature strength cannot be obtained. On the other hand, the solution treatment time is 60
Exceeding minutes will saturate the effect and increase the cost. Therefore, the solution treatment time is 10 to 6
0 minutes.

The strain of the cold working: In 6 to 35% present invention, it is important to perform the cold working at a predetermined distortion amount to the material after the solution treatment. When the strain amount of the cold working is less than 6%, precipitation strengthening during subsequent heating becomes insufficient, the initial strength is reduced, and after maintaining at a temperature of 150 ° C. for about 1000 hours, a predetermined high temperature is obtained. Can't get strength. On the other hand, when the distortion amount of the cold distortion treatment exceeds 35%, the initial high-temperature strength increases, but
After heating at 50 ° C. for a long time, the strength is remarkably reduced, and the initial strength is unnecessarily increased. When a product is punched by a press, cracks are generated or punching becomes difficult. Therefore, in the present invention, the material after the solution treatment is subjected to cold strain with a strain amount of 6 to 35%, preferably 8 to 35%. In the present invention, the method for imparting cold strain to the material after the solution treatment is not limited to cold rolling after quenching, and for example, the strain may be imparted by a stretcher.

An appropriate amount of strain in cold working for maintaining high-temperature strength after holding for a long time differs depending on the composition. The range of the strain amount is as follows: the composition is Cu: 3.0 to 4.5% by weight, Mg: 1.0 to 2.5% by weight, and M
n: 0.2 to 1.0% by weight.

The composition is Cu: 3.5 to 4.5% by weight, M
g: 1.0-2.0% by weight and Mn: 0.4-1.
In the case of 0% by weight, 5 to 20%, preferably 8 to 1%
Cold work with 5% strain. The composition is Cu: 3.
In the case of 0 to 3.8% by weight, Mg: 1.5 to 2.5% by weight, and Mn: 0.2 to 0.5% by weight, the strain amount of cold working is 10 to 35%, preferably 12-30%
And

The cold working may be performed by quenching after the solution treatment, and may be performed immediately after the quenching. However, in order to obtain a stable strength, after quenching, the steel is quenched at room temperature. After holding for 24 hours or more, it is preferable to perform cold working. In order to enhance the workability of the cold working, it is preferable to perform the cold working within 240 hours after the quenching.

Hot rolling heat treatment: 400 to 450 ° C.
The aluminum alloy ingot after soaking for 1 to 4 hours at
Hot rolling may be performed at a temperature of 400 to 450 ° C.
May be heated for 1 to 4 hours to perform a reheating treatment, and then hot-rolled. If the temperature of this heat treatment is less than 400 ° C., the deformation resistance increases and the rollability decreases,
Rolling becomes difficult. On the other hand, the heat treatment temperature is 450 ° C
If it exceeds, cracks are likely to occur.

On the other hand, if the heat treatment time is less than 1 hour, the temperature cannot be made uniform inside the alloy ingot, so that an aluminum alloy material of non-uniform quality is formed or cracks occur during hot rolling. Is more likely to occur. On the other hand, if the heat treatment time exceeds 4 hours, the effect is saturated and the cost is increased.

Accordingly, when the homogenized alloy ingot is subjected to heat treatment for hot rolling, it is required to be 400 to 450.
It is preferable to heat to a temperature of ° C. for 1 to 4 hours.

[0040]

EXAMPLES The characteristics of the aluminum alloy material produced by the method of the present invention will be specifically described below in comparison with comparative examples.

Test Example 1 4.2% by weight of Cu; 1.5% by weight of Mg;
480 ° C. using an aluminum alloy ingot (thickness: 50 mm) having a composition of 5% by weight and other unavoidable impurities
And then heated to 440 ° C. for 2 hours and then hot-rolled to a predetermined thickness.

Next, after heating to 495 ° C. for 30 minutes to perform a solution treatment, a quenching treatment was performed with water cooling. Thereafter, a cold distortion amount of 0 to 25% was applied to prepare a predetermined plate.

These materials were treated at 150 ° C. for 1 hour and 10 hours.
Table 1 below shows the results of the continuous heating for 00 hours and the investigation of the high-temperature characteristics.

[0044]

[Table 1]

As shown in Table 1, Example 1 of the present invention
Since No. 3 to No. 3 have a cold rolling ratio (amount of cold strain) in the range of 6 to 35%, after heating at 150 ° C. for 1000 hours,
Although the tensile strength is unchanged or slightly reduced, the proof stress increases. In addition, the workability after the T6 heat treatment was good. In contrast, Comparative Examples 4 and 5
Has significantly deteriorated workability, and in particular, Comparative Example 5 has significantly reduced proof stress.

Test Example 2 Cu; 3.3% by weight, Mg; 2.1% by weight, Mn;
Using an aluminum ingot (thickness: 50 mm) having a composition of 3% by weight and other unavoidable impurities, heating at 480 ° C. for 8 hours, homogenizing, further heating at 430 ° C. for 2 hours, Rolled to a predetermined thickness.

Then, after heating to 495 ° C. for 30 minutes to perform a solution treatment, a quenching treatment was performed by water cooling. Thereafter, a cold distortion amount of 15 to 30% was applied to prepare a predetermined plate.

These materials were treated at 150 ° C. for 1 hour and 10 hours.
Heating was continued for 00 hours, and the results of investigation of high-temperature characteristics after that are shown in Table 2 below.

[0049]

[Table 2]

As is evident from Table 2, in Examples 6 to 8, the yield strength after heating at 150 ° C. for 1000 hours was 1
It is greater than after heating for a time, and the workability after T6 heat treatment is also excellent. On the other hand, in Comparative Examples 9 and 10, since the cold rolling ratio was out of the range (6 to 35%) of the present invention, the high temperature proof stress was low and the workability was low.

[0051]

As described in detail above, according to the present invention,
The aluminum alloy composition and soaking and solution treatment conditions are optimized, and the appropriate amount of cold strain is applied, so the strength at room temperature is moderately low, and the workability such as punching is high. A high high-temperature strength can be obtained even after a long period of 1000 hours in a high-temperature atmosphere at 150 ° C.

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Claims (12)

[Claims] 1. Cu: 3.0 to 4.5% by weight, Mg:
It contains 1.0 to 2.5% by weight and Mn: 0.2 to 1.0% by weight, and the balance is composed of aluminum and unavoidable impurities. Distortion is caused by cold working after solution treatment. Provided, with a proof stress of 400 N at room temperature
/ Mm ² or less, an aluminum alloy material high-temperature strength superior, wherein the high temperature yield strength at 0.99 ° C. when heated 0.99 ° C. to 1000 hours is 350 N / mm ² or more. 2. The aluminum alloy material having excellent high-temperature strength according to claim 1, wherein the high-temperature proof stress is 390 N / mm ² or more. 3. The aluminum alloy material having excellent high-temperature strength according to claim 1, wherein the room temperature proof stress is 350 N / mm ² or less. 4. The aluminum alloy material having excellent high-temperature strength according to claim 1, wherein the electrical conductivity is 37 to 45% IACS. 5. The method according to claim 1, wherein the composition of the aluminum alloy is Cu:
3.5 to 4.5% by weight, Mg: 1.0 to 2.0% by weight and Mn: 0.4 to 1.0% by weight, the balance being aluminum and unavoidable impurities. The aluminum alloy material excellent in high-temperature strength according to any one of claims 1 to 4. 6. The aluminum alloy composition according to claim 1, wherein
3.0 to 3.8% by weight, Mg: 1.5 to 2.5% by weight and Mn: 0.2 to 0.5% by weight, with the balance being aluminum and unavoidable impurities. The aluminum alloy material excellent in high-temperature strength according to any one of claims 1 to 4. 7. Further, Cr: 0.10% by weight or less, Z
The method according to any one of claims 1 to 6, further comprising at least one element selected from the group consisting of r: 0.20% by weight or less and Ti: 0.05% by weight or less. Aluminum alloy material with excellent high-temperature strength. 8. Cu: 3.0 to 4.5% by weight, Mg:
An aluminum alloy ingot having a composition containing 1.0 to 2.5% by weight and Mn: 0.2 to 1.0% by weight, and the balance consisting of aluminum and unavoidable impurities was 440 to 51%.
A one-stage or two-stage soaking process of heating at a temperature of 0 ° C. for 2 to 24 hours, a process of hot rolling the ingot after the soaking process, and a process of heating an aluminum alloy material at a temperature of 470 to 510 ° C. for 10 to 60 hours. Heating the solution-treated material by a minute, cold-working the solution-processed material with a strain amount of 6 to 35%,
Aging treatment. A method for producing an aluminum alloy material having excellent high-temperature strength. 9. Cu: 3.5 to 4.5% by weight, Mg:
An aluminum alloy ingot having a composition containing 1.0 to 2.0% by weight and Mn: 0.4 to 1.0% by weight, and the balance consisting of aluminum and inevitable impurities is 440 to 51%.
A one-stage or two-stage soaking process of heating at a temperature of 0 ° C. for 2 to 24 hours, a process of hot rolling the ingot after the soaking process, and a process of heating an aluminum alloy material at a temperature of 470 to 510 ° C. for 10 to 60 hours. A step of heat-treating by solution heating for a minute, and a step of cold-working the solution-processed material with a strain amount of 5 to 20%.
Aging treatment. A method for producing an aluminum alloy material having excellent high-temperature strength. 10. Cu: 3.0 to 3.8% by weight, M
g: 1.5 to 2.5% by weight and Mn: 0.2 to 0.
A one-stage or two-stage soaking process in which an aluminum alloy ingot containing 5% by weight and the balance consisting of aluminum and inevitable impurities is heated at a temperature of 440 to 510 ° C. for 2 to 24 hours; Hot rolling the ingot, heat treating the aluminum alloy material at a temperature of 470 to 510 ° C. for 10 to 60 minutes, and cooling the solution heat treated material at a strain of 10 to 35%. A method for producing an aluminum alloy material having excellent high-temperature strength, comprising a step of cold working and a step of aging. 11. The method according to claim 8, further comprising a step of cold working the aluminum alloy material between the hot rolling step and the solution treatment step. A method for producing an aluminum alloy material having excellent high-temperature strength. 12. The aluminum alloy further comprises C
9. The composition according to claim 8, further comprising at least one element selected from the group consisting of r: 0.10% by weight or less, Zr: 0.20% by weight or less, and Ti: 0.05% by weight or less. 12. The method for producing an aluminum alloy material excellent in high-temperature strength according to any one of items 11 to 11.