JPH0517858A - Manufacture of aluminum alloy excellent in formability - Google Patents

Abstract

PURPOSE:To manufacture an aluminum alloy having uniform and fine crystalline grains even after the final forming to a high tensile strength aluminum alloy for forming used as the material for aircraft, the material for structural purposes or the like and free from the generation of the roughening of the surface. CONSTITUTION:An aluminum alloy having features that an aluminum alloy contg., as essential elements, by weight, 4.0 to 7.0% Cu, 0.1 to 0.6% Mn, 0.01 to O.2% V, 0.05 to 0.3% Zr and 0.01 to 0.l5% Ti and the balance aluminum with inevitable impurities is subjected to homogenizing treatment, is thereafter subjected to hot rolling and cold rolling, is then held under heating at 470 to 550 deg.C, is thereafter cooled to the room temp. or below, is next subjected to 20 to 75% working, is furthermore subjected to softening treatment at 360 to 500 deg.C to regulate the maximum grain size at this time to 50mum and excellent in formability is prepd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength aluminum alloy for forming, and more particularly to a conventional method 200
The present invention relates to a method for producing an aluminum alloy containing Cu, Mn, V, Zr, and Ti, which is represented by a 0-based alloy, which does not cause rough skin even when subjected to a forming process after the softening treatment.

[0002]

2. Description of the Related Art Conventionally, aluminum alloys for forming, for example, alloys such as 2024 have been used in large quantities as aircraft materials or other structural materials. Usually, they are preformed with a soft material, and then a solution is used. A manufacturing process is carried out in which aging and quenching are performed, and after final shaping is performed in a short time of low strength immediately after quenching, aging treatment is performed to obtain a high-strength aluminum alloy. 1 with conventional soft material
The part that has been preformed by about 20% has a remarkably coarse recrystallized structure in the subsequent solutionizing, quenching, etc., and the surface is roughened or microcracks are generated in the final forming process, resulting in an aluminum product. Was a cause of deterioration of the performance of.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, and to perform all the cold rolling, drawing, swaging, cold forging, etc. performed on soft materials such as plate materials, pipe materials and bar materials. This is a method for producing an aluminum alloy which has excellent reproducibility in formability without roughening of recrystallized grains after hot working and uniform fine grains even after final forming.

[0004]

The present invention is based on Cu4.0 to Cu4.0.
7.0 wt%, Mn 0.1-0.6 wt%, V0.01-
0.2 wt%, Zr0.05-0.3 wt%, Ti0.01
Aluminum alloy containing 0.15 wt% as an essential element and the balance aluminum and unavoidable impurities is homogenized, hot-rolled and cold-rolled.
After heating and holding at 0 to 550 ° C., cooling to a temperature of room temperature or lower, then 20 to 75% processing, and further 360 to
Softening treatment at 500 ℃, the maximum grain size at that time is 5
It is a method for producing an aluminum alloy having excellent formability, which is characterized by being 0 μm or less.

[0005]

In the present invention, the alloy composition is limited as described above for the following reason. The reason for limiting the Cu content to 4.0 to 7.0 wt% is that if the Cu content is less than 4.0 wt%, sufficient strength cannot be obtained even after solution treatment and aging treatment after molding, and 7.0 wt% %, Cu-based intermetallic compounds tend to be broken out and the toughness deteriorates, as well as the cold rolling property and the moldability deteriorate, which is not preferable. Mn content is 0.1-0.6 wt%, Zr content is 0.05-
0.3 wt% and Ti content 0.01-0.15 wt%
When the content is less than the lower limit, the crystal grains are not refined and the moldability is not improved, and when the content exceeds the upper limit, the cold rolling property and the moldability are deteriorated, which is not preferable. The content of V is limited to 0.01 to 0.2 wt% because if it is less than 0.01 wt%, the effect of heat resistance cannot be obtained, and if it exceeds 0.2 wt%, cold rolling property and formability are deteriorated. It is not preferable because it causes The reason why the manufacturing method is limited as described above is as follows. First, after performing homogenization treatment, hot rolling and cold rolling by a conventional method,
After heating and holding at 470 to 550 ° C., cooling to a temperature equal to or lower than room temperature is performed by dissolving the solute element in the matrix, or by G. This is because the P phase or the θ ′ intermediate phase is deposited. If it is less than 470 ° C, it cannot be sufficiently dissolved, and if it exceeds 550 ° C, eutectic melting occurs, which is not preferable. The holding time at this time may be several minutes, but if possible, it is desirable to hold it for a sufficient time. The cooling rate is preferably 0.6 ° C./min. Or higher, and water quenching is desirable if possible.

Next, the processing of 20 to 75% is carried out in order to introduce a proper amount of dislocations necessary for obtaining fine recrystallized grains. If it is less than 20%, the amount of dislocations is small, and it is 75%.
If it exceeds, the amount of dislocations increases and the recrystallized grains increase in either case, which is not preferable. Next, the softening treatment is performed at 360 to 500 ° C. in order to distribute the dislocations introduced in the processing as a fine and uniform cell structure and obtain a fine recrystallized structure using the dislocations as nuclei. If it is lower than 360 ° C., it is not sufficiently softened, and if it exceeds 500 ° C., crystal grains grow remarkably, which is not preferable. The heating rate at this time is preferably 40 ° C./hr. Or more. The holding time is several minutes to several hours on the high temperature side, and up to about 6 hours is sufficient on the low temperature side.
Further, the cooling after softening is preferably slow cooling. Next, the maximum crystal grain size after softening is limited to 50 μm or less because when it exceeds 50 μm, the effect of preventing rough skin after final molding does not appear.

[0007]

[Examples] Alloys having the compositions shown in Table 1 were cast by an ordinary melting method, faced, homogenized at 490 ° C. for 24 hours, hot-rolled and cold-rolled, and a plate material having a thickness of 2 mm And
Samples were obtained by subjecting this plate material to the treatment conditions according to the method of the present invention and the comparative method shown in Table 2 and the conventional annealing treatment. In either case, after solution treatment, water-cool to room temperature,
Softening treatment is heated at 80 ℃ / hr., Then 25 ℃ up to 250 ℃
It was gradually cooled at a cooling rate of / hr. The maximum crystal grain after softening was measured using an image analysis device. In order to test the performance of the inventive material, comparative material and conventional material obtained in this way, 0 to 20% preforming processing (tensile in the L direction) shown in Tables 3 and 4 was performed, and then solution hardening was performed. Treatment (500 ℃ × 1
Immediately after carrying out hr. water cooling, final molding processing (2-10% L)
The presence or absence of rough skin was confirmed by performing directional tension).

[0008]

[Table 1]

[0009]

[Table 2]

[0010]

[Table 3]

[0011]

[Table 4]

As is clear from Tables 3 and 4, the material of the present invention is
Even after the softening treatment, the size of the largest crystal grain was fine, and the roughening after the final molding was not observed even if the preforming ratio was different.

[0013]

As described above, according to the method of the present invention, the portion that has been preformed with the softening-treated material has a uniform fine recrystallized structure even if the solution hardening treatment is performed in the subsequent step, and the final It is possible to manufacture an aluminum alloy having excellent moldability without causing rough skin even after the molding process.

Claims (1)

Claims 1. Cu 4.0-7.0 wt%, Mn 0.1
0.6 wt%, V0.01-0.2 wt%, Zr0.05-
An aluminum alloy containing 0.3 wt% and Ti 0.01 to 0.15 wt% as essential elements, the balance being aluminum and unavoidable impurities, is subjected to homogenization treatment, followed by hot rolling and cold rolling, and then at 470 to 550 ° C. After heating and holding at
After cooling to a temperature below room temperature, 20-75% processing is then performed, and further softening treatment is performed at 360-500 ° C.
A method for producing an aluminum alloy having excellent formability, wherein the maximum crystal grain size at that time is 50 μm or less.