JPH08232051A - Production of aluminum alloy forged product - Google Patents

Abstract

PURPOSE: To reduce man-hours, to shorten working time, and to reduce the cost of forged products by enabling forging at a temp. in the range of solution heat treatment and performing hardening without delay while obviating the necessity of solution heat treatment after forging. CONSTITUTION: An aluminum alloy, which has a composition consisting of 0.5-1.5% Si, 0.5-1.5% Mg, 0.2-1.2% Cu, 0.05-0.3% Zr, and the balance Al with inevitable impurities and further containing, if necessary, 0.05-1.0% Mn, 0.02-0.35% Cr, and 0.01-0.25% Ti, is used. This aluminum alloy is hot-forged at 450-580 deg.C. After forging the resulting forged product is subjected to solution heat treatment and hardening at 490-580 deg.C, or, after the completion of forging, hardening is done before the temp. of the forged product reaches <490 deg.C. After hardening, artificial aging treatment is done. By this method, the necessity of the energy for reheating can be obviated even in the case where solution heat treatment is done after forging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a forged aluminum alloy product, and particularly to Si and M as essential alloy components
The present invention relates to a method for producing a 6000 series aluminum alloy forged product containing g, Cu and Zr.

[0002]

2. Description of the Related Art With the demand for weight reduction of automobiles and motorcycles, aluminum alloy materials have been used for these components.
Since 00 series aluminum alloys have excellent forgeability, they can be used as stamped forged products or free forged products for wheels,
It is applied to various parts such as suspension parts and hydraulic system cases.

Forged products of 6000 series aluminum alloys are
Usually, it is provided in a state where it has been subjected to age hardening treatment, but conventionally, the manufacturing process is, for example, hot forging at a temperature of 350 to 450 ° C, after forging, once cooled to room temperature, and 510 to 550 ° C.
It is a solution treatment at a certain temperature, quenching, and an aging treatment.In the solution treatment temperature range, the crystal grains become coarse and the forgeability decreases, so hot forging is performed at the solution treatment temperature. Since it cannot be performed and the hot forging and the solution heat treatment have to be performed in different temperature ranges, there is a facility difficulty that another heating furnace is required.

When the degree of forging is low due to the shape of the product, hot forging may be possible within the solution treatment temperature range, but the 6000 series alloy has high quenching susceptibility and cooling from the solution treatment temperature. If the speed is slowed down, quenching will not occur, so even if hot forging is started at the solution treatment temperature, a sufficient quenching effect will not be obtained against the temperature drop during forging, and the solution treatment temperature after forging will not be restored. Even if quenching and aging treatment are performed immediately without heating, sufficient strength characteristics are often not obtained.

Therefore, after hot forging, it is essential to reheat to the solution heat treatment temperature, which is a cause of increasing the number of production steps and working time. After hot forging, by raising the temperature to a predetermined solution heat treatment temperature before the temperature of the hot forged product decreases, a method of speeding up the temperature rise to the solution heat treatment temperature and reducing the production lead time is also available. The proposal (Japanese Patent Application Laid-Open No. 2-185956) does not provide a drastic solution to the production cost because reheating is required because the forging temperature and the solution treatment temperature are different.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems in the production of a hot forged product of a 6000 series aluminum alloy, and its purpose is to set the content range of each alloy element. The specific combination of improves the forgeability at the solution heat treatment temperature, reduces the quenching sensitivity to improve the strength characteristics, and enables the forging process within the solution heat treatment temperature range. It is an object of the present invention to provide a method for manufacturing an aluminum alloy forged product, which can achieve reduction in production man-hours and working time by performing quenching and artificial aging treatment immediately without reheating.

[0007]

A method for manufacturing an aluminum alloy forged product according to the present invention for achieving the above object is as follows: Si: 0.5-1.5%, Mg: 0.5-1.5%, Cu: 0.2-
1.2%, Zr: 0.05-0.3%, Mn: 0.05-1.0%, Cr: 0.02-0.35% and T if necessary.
i: contains one or more of 0.01 to 0.25%,
Aluminum alloy consisting of balance Al and unavoidable impurities
After hot forging at a temperature of 450 to 580 ℃, then 490 to 580 ℃
The first feature is that the solution treatment is performed at the temperature of, and quenching and aging are performed.

Further, the above aluminum alloy is used in the range of 450-580.
The second feature of the present invention is to perform hot forging at a temperature of ℃, quench before the temperature of the hot forged aluminum alloy becomes lower than 490 ° C, and further perform aging treatment.

In order to achieve the above object of the present invention, first, the composition of the Al--Si--Mg alloy of the present invention must be limited to a specific range. Explaining the meaning and limitation reason of alloying elements in the present invention, Si is Mg
Copresence with Mg to precipitate Mg ₂ Si particles in the matrix and improve the strength of the alloy. The preferred content range is 0.5
If it is less than 0.5%, sufficient strength cannot be obtained, and if it exceeds 1.5%, simple Si crystallizes in the matrix, deteriorating workability and hardenability.

Mg coexists with Si and Cu to enhance the strength of the alloy. The preferred content range is 0.5 to 1.5%. If it is less than 0.5%, the strength is insufficient, and if it exceeds 1.5%, the workability and the hardenability are deteriorated. Cu is Mg
By including it in combination with Al-Cu-Mg-based particles, it helps to improve the strength. It is preferable to contain it in the range of 0.2 to 1.2%. If it is less than 0.2%, a sufficient strength improving effect cannot be obtained, and if it exceeds 1.2%, workability and hardenability become poor.

Zr refines recrystallized grains to improve workability. The preferred content range is 0.05 to 0.3%,
If it is less than 0.1%, the effect is small, and if it exceeds 0.3%, a huge insoluble intermetallic compound is formed, which deteriorates the ductility and weakens the recrystallization refining effect. Mn added as a selective component,
By containing Cr and Ti in combination with Zr, Al-Mn- (Si) system and Al-Cr are contained in the matrix.
And Al-Ti type fine compound particles are precipitated to further improve the effect of refining recrystallized grains. If it is less than the lower limit, the effect is small, and if it exceeds the upper limit, a huge intermetallic compound is formed and ductility is lowered.

In the present invention, Al having the above composition is used.
-Si-Mg-based aluminum alloy forging material is processed into a desired forged product by stamping forging or free forging, and is directly quenched without reheating from the forging end temperature, or cooled to room temperature and reheated or forged A predetermined aluminum alloy forged product is obtained by heating from the temperature to raise the temperature to the solution heat treatment temperature, followed by quenching treatment and artificial aging treatment.

The forging temperature is 450 to 580 ° C. both when reheating from the forging end temperature to the solution treatment temperature and when directly quenching without reheating from the forging end temperature.
Is preferred. If the forging temperature is lower than 450 ° C., Mg ₂ Si is precipitated due to the temperature decrease after forging, and sufficient strength cannot be obtained after quenching and aging treatment. If the forging temperature exceeds 580 ° C, the workability deteriorates and the melting may occur. A more preferable forging temperature is in the range of 520 to 580 ° C.

After forging, the solution treatment temperature when reheating from the forging end temperature to the solution treatment temperature is 490 to 580.
C. is preferably in the range of 520 to 580.degree. If the temperature is lower than 490 ° C, sufficient strength cannot be obtained after the aging treatment, and if the temperature exceeds 580 ° C, the workability is deteriorated and dissolution may occur.

During forging, the temperature of the aluminum alloy material rises due to processing heat and usually reaches 490 ° C. or higher. Therefore, when directly quenching from the forging end temperature, the temperature of the forged product is 490 ° C. after the forging is completed. Before dropping to less than, preferably 52
Quenching is performed before the temperature drops below 0 ° C. At temperatures below 490 ° C, coarse Mg ₂ Si precipitation occurs,
It is difficult to obtain sufficient strength after aging. Quenching treatment is usually performed by putting a forged product in a water tank. After quenching,
Similar to the case of a general 6000 series aluminum alloy, artificial aging treatment is performed, for example, at 170 to 180 ° C. for 8 hours.

[0016]

In the present invention, when the 6000 series aluminum alloy is subjected to hot forging, solution treatment, quenching and aging treatment, the alloy composition is specified to reduce quenching sensitivity and prevent coarsening of recrystallized grains. By improving the workability, by combining a specific alloy composition with a predetermined forging and solution treatment temperature and quenching conditions, it is possible to perform hot forging and solution treatment in the same temperature range,
After hot forging, quenching can be done immediately without reheating to the solution heat treatment temperature, which significantly reduces the production man-hours and working time, and eliminates the need for energy for solution heat treatment. Product cost reduction can be achieved.

Further, even when reheating to the solution heat treatment temperature after hot forging, the hot forging and the solution heat treatment are performed in the same temperature range, and therefore, the same for heating and solution heat treatment of the forging material is performed. It is also possible to use a heating furnace, and it is possible to obtain facility advantages.Furthermore, the temperature of the forged material rises due to the processing heat during forging and is maintained within the solution treatment temperature range, so immediately after the forging is completed. Energy loss is reduced by sending it to the heating furnace, which helps reduce the cost of the forged product.

[0018]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 A forging material made of an aluminum alloy having the composition shown in Table 1 was hot forged at 520 ° C, and after the forging, when the forged product reached a temperature of 500 ° C, it was put into a water tank and quenched. Further, artificial aging treatment was performed at 170 ° C for 8 hours. Mechanical properties of the obtained forged product (tensile strength: σ _B , yield strength:
The forgeability was evaluated by measuring σ _0.2 and elongation: δ) and observing the presence or absence of defects such as cracks, wrinkles and fog on the appearance of the forged product. The results are shown in Table 1. As shown in Table 1, each of the forged products according to the present invention has an excellent proof stress of 330 MPa or more, and there is no defect in the appearance of the forged product and it has good forgeability.

[0019]

[Table 1]

Comparative Example 1 A forging material made of an aluminum alloy having the composition shown in Table 2 was subjected to forging, quenching, under the same conditions as in Example 1.
With regard to the forged product obtained by performing the artificial aging treatment, the mechanical properties were measured and the forgeability was evaluated in the same manner as in Example 1. Table 2 shows the results. In Table 2, those that do not satisfy the conditions of the present invention are underlined.

[0021]

[Table 2] <Table Note> Test material No.21: 6063 alloy, test material No.22: 6N01 alloy, test material No.23: 6061 alloy Forgeability ○: Good

As shown in Table 2, test materials No. 13 and 1
In Nos. 5 and 17, since Si, Cu, and Mg are less than the lower limit of the present invention, respectively, the yield strength is less than 300 MPa and the strength is insufficient. Test materials Nos. 14, 16, and 18 are Si, Cu, and M, respectively.
Since g was above the upper limit, workability was poor, and cracks occurred during forging. Since the Zr content of the test material No. 19 was less than the lower limit, the recrystallized grains were large and wrinkles were generated due to uneven deformation during forging. Since Zr of the test material No. 20 exceeds the upper limit value, cracking occurred during forging. Test material No.21
Nos. 23 to 23 are conventional alloys, and all have wrinkles during forging and insufficient strength.

Example 2 and Comparative Example 2 A forging material of an aluminum alloy containing Si: 0.9%, Mg: 0.8%, Cu: 0.5%, Zr: 0.10% and the balance Al and unavoidable impurities is shown in Table 1. Hot forging was carried out at the temperature shown in FIG. 3, and after the forging was completed, when the temperature of the forged product reached the temperature shown in Table 3, the forged product was put into a water tank and quenched. Then 170 ℃
About 8 hours of artificial aging treatment, the obtained forged product,
In the same manner as in Example 1, the mechanical properties were measured and the forgeability was evaluated. The results are shown in Table 3. In Table 3, those that do not satisfy the conditions of the present invention are underlined.

[0024]

[Table 3]

As shown in Table 3, the test materials No. 24 to 28 according to the conditions of the present invention have excellent strength exceeding 320 MPa in yield strength and good forgeability.
For No. 9, the forging temperature was too high, so the workability deteriorated and cracking occurred during forging. Since test material No. 30 has a low forging temperature and test material No. 31 has a low quenching temperature, sufficient strength cannot be obtained.

Example 3 A forging material made of an aluminum alloy having the composition shown in Table 4 was hot forged at a temperature of 520 ° C, and then 520 ° C.
After the solution heat treatment was performed at the temperature of 1, the mixture was placed in a water tank, quenched, and artificially aged at 170 ° C. for 8 hours. The mechanical properties of the obtained forged product were measured in the same manner as in Example 1 to evaluate the forgeability. The results are shown in Table 4. As shown in Table 4, all the test materials according to the present invention have excellent strength and good forgeability.

[0027]

[Table 4]

Comparative Example 3 A forging material of an aluminum alloy having the composition shown in Table 5 was forged at a temperature of 520 ° C. as in Example 3, and after forging, solution heat treated at a temperature of 520 ° C. to prepare a water tank. After charging and quenching, artificial aging treatment was performed at 170 ° C for 8 hours. The mechanical properties of the obtained forged product were measured and the forgeability was evaluated. The results are shown in Table 5. In Table 5, those that did not satisfy the conditions of the present invention are underlined.

[0029]

[Table 5] << Table Note >> Test material No.52: 6063 alloy, test material No.53: 6N01 alloy, test material No.54: 6061 alloy

As shown in Table 5, test materials No. 44 and 4
In Nos. 6 and 48, since the amounts of Si, Cu, and Mg are less than the lower limit of the present invention, respectively, the yield strength is 300 MPa or less and sufficient strength is not obtained. Test materials No. 45, 47, and 49 are S
Since i, Cu, and Mg exceeded the upper limits, workability was poor and cracking occurred during forging. Since the test material No. 50 had a small amount of Zr, the effect of refinement of recrystallization was small, and wrinkles were generated due to uneven deformation during forging. Since the test material No. 51 contained too much Zr, the ductility decreased and cracking occurred during forging. Test material N
O.52 to 54 are conventional alloys with poor workability, and wrinkles occur during forging, and strength is not sufficient.

Example 4, Comparative Example 4 A forging material of an aluminum alloy containing Si: 0.9%, Mg: 0.8%, Cu: 0.5%, Zr: 0.10%, and the balance Al and unavoidable impurities was prepared. After hot forging at the forging temperature shown in Table 6, solution treatment was carried out at the solution treatment temperature shown in Table 6, and the solution was placed in a water tank for quenching and further subjected to artificial aging treatment at 170 ° C. for 8 hours. The mechanical properties of the obtained forged product were measured as in Example 1. The results are shown in Table 6.
In Table 6, those that did not satisfy the conditions of the present invention are underlined.

[0032]

[Table 6]

As shown in Table 6, all of the test materials No. 55 to 59 according to the conditions of the present invention showed high strength, but the test materials No. 60 and 61 had low forging temperatures, and the test materials No. 63
Since the solution treatment temperature is low, sufficient strength cannot be obtained,
For the test material No. 62, the solution treatment temperature was too high, so partial melting occurred and the forged product was deformed.

[0034]

As described above, according to the present invention, it is possible to perform hot forging at a solution treatment temperature. Therefore, by quenching immediately after forging, it is possible to reduce the number of production steps and the working time. The cost reduction of the aluminum alloy forged product can be achieved. Even when the solution heat treatment is performed after the forging is completed, the energy required for reheating is small, and the heating of the forging material and the heat treatment for the solution heat treatment can be performed in the same furnace.

Claims (4)

[Claims] 1. Si: 0.5 to 1.5% (mass%, the same applies hereinafter), Mg: 0.5 to 1.5%, Cu: 0.2 to 1.2% and Z
r: 0.05-0.3%, aluminum alloy consisting of balance Al and unavoidable impurities was hot forged at a temperature of 450-580 ° C, then solution heat-treated at a temperature of 490-580 ° C for quenching and aging. A method for manufacturing an aluminum alloy forged product, which comprises processing. 2. The aluminum alloy contains Si: 0.5 to 1.5%,
Mg: 0.5-1.5%, Cu: 0.2-1.2%, Zr: 0.05-0.
3%, Mn: 0.05-1.0%, Cr: 0.02
.About.0.35% and Ti: 0.01 to 0.25% and one or more of them, and the balance Al and unavoidable impurities are contained, and the method for producing an aluminum alloy forged product according to claim 1. 3. Si: 0.5-1.5%, Mg: 0.5-1.5%,
Cu: 0.2 to 1.2% and Zr: 0.05 to 0.3%,
An aluminum alloy consisting of the balance Al and unavoidable impurities is hot forged at a temperature of 450 to 580 ° C, quenched before the temperature of the hot forged aluminum alloy falls below 490 ° C, and further aged. And a method for manufacturing an aluminum alloy forged product. 4. The aluminum alloy contains Si: 0.5 to 1.5%,
Mg: 0.5-1.5%, Cu: 0.2-1.2%, Zr: 0.05-0.
3%, Mn: 0.05-1.0%, Cr: 0.02
The method for manufacturing an aluminum alloy forged product according to claim 3, wherein the aluminum alloy forged product contains at least one of 0.3 to 0.35% and Ti: 0.01 to 0.25%, and the balance is Al and inevitable impurities.