KR20200034729A - Aluminum alloy plate and its manufacturing method - Google Patents

Abstract

The aluminum alloy plate contains, in mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less. , The balance has a composition consisting of Al and inevitable impurities.

Description

Aluminum alloy plate and its manufacturing method

The present invention includes, for example, members and components used in various automobiles represented by automobile body seats and body panels, members and components used in ships, aircraft, and the like, or construction materials, structural materials, and various other mechanical devices and household appliances. Or its parts, such as aluminum alloy plates used by forming and painting and baking, especially Al-Mg-based aluminum with high tensile strength and excellent press moldability and stress corrosion cracking resistance. It relates to an alloy plate, and a manufacturing method thereof.

In the past, cold rolled steel sheets have been often used for body seats used in automobiles, but recently, in view of suppressing global warming and reducing energy costs, there has been an increasing demand for lighter automobiles to improve fuel efficiency. , So, instead of the conventional cold rolled steel sheet, there is an increasing tendency to use an aluminum alloy sheet having a strength almost equal to that of a cold rolled steel sheet and a specific gravity of about 1/3 for a body sheet of automobiles.

By the way, as an aluminum alloy for an automobile body sheet, an Al-Mg-based alloy, for example, a 5000-based Al alloy containing 3.5 mass% or more of Mg, such as 5056, 5082, 5182, 5083, 5086, is used. Since these Al-Mg-based alloys have high strength, good moldability, and excellent weldability, they are used as welded structural members.

However, when the Al-Mg-based alloy is used as a structural material and used for a long time in a stress-loaded state, there is a problem that stress corrosion cracking is likely to occur because the Mg content is high. In order to prevent this stress corrosion cracking, it is effective to perform a surface treatment such as painting on a substrate made of an Al-Mg-based alloy, but it is necessary to use this substrate as a structural material for uncoating. It is required that the substrate itself made of -Mg-based alloy has excellent stress corrosion cracking resistance.

It is known that the stress corrosion cracking in the Al-Mg-based alloy preferentially successively deposits the β phase (Al ₃ Mg ₂ ) at the grain boundary over time, and is promoted by the β phase precipitated by the grain boundary. For this reason, conventionally, in order to prevent stress corrosion cracking of Al-Mg-based alloys with a large amount of Mg, it has been proposed in various ways to suppress continuous precipitation of grain boundaries in the β phase.

For example, in Patent Document 1, cooling after the hot rolling and cold rolling followed by solution treatment was performed in two stages under conditions of different cooling rates in the high temperature region and the low temperature region, and the cooling rate in the low temperature region was increased. A method of manufacturing an Al-Mg-Cu-based aluminum alloy sheet for molding processing that can prevent continuous precipitation of a β phase with respect to grain boundaries during cooling by speeding it up is described.

In addition, Patent Document 2 describes a structural aluminum alloy plate containing Mg: 3.5 to 5.5%, the strength after the final annealing treatment is 250 N / mm 2 or more, and the conductivity after the annealing treatment is 26.5 to 29.6 IACS%, According to such a description, it is said that it is possible to improve the stress corrosion cracking resistance without lowering the strength characteristics by setting the conductivity to 29.6 IACS% or less, by depositing and dissolving the total of the precipitates containing the β phase.

Japanese Patent Application Publication No. 2003-231956 Japanese Patent Application Publication No. 2001-32031

However, the aluminum alloy plate described in Patent Document 1 has a problem that, since the Cu content is high at 0.5 to 1.8 mass%, hot workability decreases, coarse compounds are formed, and moldability is inferior. In order to manufacture the aluminum alloy plate, it is necessary to perform cooling in two stages after performing the solution treatment, and to increase the cooling rate in the low-temperature region, but if the cooling rate is increased, shape accuracy such as flatness after treatment There is also the problem that it gets worse.

In addition, the structural aluminum alloy plate described in Patent Literature 2 uses only Mg as an essential component and limits the strength and conductivity after the final annealing treatment, but the content of specific components other than Mg indicates tensile strength, There is no disclosure or suggestion about the influence on the superiority of press formability and stress corrosion cracking, and in order to manufacture such an aluminum alloy plate, the cooling rate during casting is increased and cold rolling is performed. It is necessary to increase the cooling rate in cooling after heating in the intermediate annealing and in the final annealing after cold rolling, which leads to a decrease in productivity due to an increase in the number of manufacturing processes or tight control of manufacturing conditions. There is.

The present invention has been made by paying attention to such circumstances, and its purpose is to provide an aluminum alloy plate having high tensile strength and also excellent in press formability and stress corrosion cracking resistance, in particular, an Al-Mg-based aluminum alloy plate and its manufacture. Is to provide a way.

In order to solve the above problems, the present inventors conducted various experiments and reviews on the compositional components and manufacturing processes of Al-Mg-based alloys, and by limiting the compositional components and manufacturing processes to appropriate conditions, the aluminum alloy plate was It has been found that it is possible to control the size and number density of the intermetallic compounds present, thereby succeeding in the development of an aluminum alloy plate which also has excellent press formability and stress corrosion cracking resistance while maintaining high tensile strength. Came to complete.

That is, each embodiment of the aluminum alloy plate and its manufacturing method is as follows.

(1) In mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50% and Mn: more than 0.05% and containing 0.35% or less, cup Aluminum alloy plate, characterized in that it has a composition consisting of additional Al and inevitable impurities.

(2) The aluminum alloy plate according to the above (1), characterized in that the equivalent circle diameter is 0.1 to 0.5 µm, and the number density of the intermetallic compound not containing Cu is 1 × 10 ⁶ pieces / mm 2 or less.

(3) The aluminum alloy plate according to (1) above, wherein the equivalent circle diameter is 0.3 to 4 µm, and the number density of the intermetallic compounds containing Cu is 1 × 10 ⁴ particles / mm 2 or more.

(4) Cu: The aluminum alloy plate according to (1) above, which is 0.13 to 0.35 mass%.

(5) The aluminum alloy plate according to (1) above, wherein the composition further contains one or two of Ti: 0.05 mass% or less and B: 0.05 mass% or less.

(6) In mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less, and As a method for producing an aluminum alloy plate having a composition consisting of additional Al and inevitable impurities,

The ingot obtained by casting the aluminum alloy material having the above composition is subjected to a homogenization treatment at a first temperature in the range of 490 to 580 ° C, and thereafter, a second in the range of 430 to 500 ° C and lower than the first temperature After cooling the temperature to an average cooling rate in the range of 500 to 3000 ° C / h, hot rolling is started while maintaining the second temperature, and then wound up at a third temperature in the range of 320 to 380 ° C, after which , Cold rolling and final annealing treatment are sequentially performed.

(7) The first temperature is in the range of 500 to 570 ° C,

The second temperature is in the range of 440 ~ 490 ℃,

The manufacturing method of the aluminum alloy plate as described in said (6) characterized by the said 3rd temperature being in the range of 340-360 degreeC.

According to one embodiment, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50% and Mn: more than 0.05% and 0.35% or less in mass% And the remainder has a composition composed of Al and inevitable impurities, while having high tensile strength, excellent press formability and stress corrosion corrosion resistance, an aluminum alloy plate, in particular, an Al-Mg-based aluminum alloy plate and a method of manufacturing the same Provision was made possible.

Next, a preferred embodiment will be described.

The aluminum alloy plate according to one embodiment is in mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50% and Mn: more than 0.05% and 0.35% It contains the following, and the balance has a composition composed of Al and unavoidable impurities.

Hereinafter, the reason for limiting the chemical composition of the aluminum alloy plate according to the embodiment will be described. In addition, although the unit of content of the element in a chemical composition is all "mass%", hereafter, it expresses simply as "%" unless there is particular notice.

(I) Chemical composition

<Si: 0.03 to 0.35%>

Si (silicon) has an effect of improving stress corrosion cracking resistance, and is one of important components in one embodiment. When the Si content is less than 0.03%, preferential precipitation to the grain boundary of the β phase (Al ₃ Mg ₂ ) cannot be prevented, stress corrosion cracking resistance deteriorates, and crystal grains after final annealing coarsen and surface roughness occurs. Because it becomes easy to do. Moreover, when Si content is more than 0.35%, it is because an intermetallic compound is formed and press formability, especially elongation property and deep drawing property deteriorates. For this reason, the Si content is in the range of 0.03 to 0.35%, and preferably in the range of 0.09 to 0.25%.

<Fe: 0.03 to 0.35%>

Fe (iron) also has a function of improving stress corrosion cracking resistance, like Si, and is one of the important components in one embodiment. When the Fe content is less than 0.03%, the precipitation of the β phase (Al ₃ Mg ₂ ) at the grain boundary cannot be prevented, the stress corrosion cracking resistance deteriorates, and the crystal grains after the final annealing become coarse and surface roughness occurs. It becomes easy to do. Moreover, when the Fe content is more than 0.35%, an intermetallic compound is formed to deteriorate the press formability, especially the elongation property and the deep drawing property. For this reason, the Fe content is in the range of 0.03 to 0.35%, and preferably in the range of 0.09 to 0.25%.

<Mg: 3.0 to 5.0%>

Mg (magnesium) is a component having the effect of improving the work hardenability and improving the elongation and deep drawing properties. In order to exhibit such an action, it is necessary to contain Mg content of 3.0% or more. Further, even if the Mg content is more than 5.0%, not only the additional improvement effect of the above properties cannot be expected, but also the stress corrosion cracking resistance and hot rolling property are remarkably lowered. For this reason, the Mg content is in the range of 3.0 to 5.0%, and preferably in the range of 3.2 to 4.7%.

<Cu: more than 0.09% and less than 0.50%>

Cu (copper), like Mg, is a component having the effect of improving the work hardenability and improving the elongation and deep drawing properties. Moreover, Cu also has the effect of suppressing the grain boundary precipitation of the β phase and improving the stress corrosion cracking resistance by forming an Al-Mg-Cu-based compound. In order to exert such action, it is necessary to contain Cu content exceeding 0.09%. Moreover, when Cu content is 0.50% or more, hot workability falls and coarse compounds are formed and press formability falls. For this reason, the Cu content is in the range of more than 0.09% and less than 0.50%, and preferably in the range of more than 0.09% and 0.35% or less.

<Mn: more than 0.05% and 0.35% or less>

Mn (manganese) is a component having an action of improving the refining grain size and strength after the final heat treatment. In order to exert the above action, it is necessary that the Mn content is more than 0.05%. On the other hand, when the Mn content is more than 0.35%, the size of the recrystallized grains becomes too small, so that a stretch-strain mark (deformation pattern (wrinkle) appearing on the surface of the alloy plate) tends to occur on the surface of the press-formed alloy plate. Moreover, moldability also falls.

As described above, the aluminum alloy plate of one embodiment uses Si, Fe, Mg, Cu, and Mn as essential components, but if necessary, one of Ti: 0.05% or less and B: 0.05% or less, or Two kinds can be further contained.

<Ti: 0.05% or less and B: 0.05% or less of 1 or 2 types>

Ti and B are components having an action to refine the crystal grains of the ingot. If the content of Ti and B is not more than 0.05%, the range is not more than 0.05% from the viewpoint of not adversely affecting press formability and stress corrosion cracking resistance.

<Residue: Al and inevitable impurities>

Besides each of the above elements, Al (aluminum) and inevitable impurities.

Even if V, Sc, Na, Be, and Bi are contained in a range of 0.1% or less, there is no effect on the implementation of one embodiment.

(II) Number density of intermetallic compounds

(i) The number density of intermetallic compounds having a circle equivalent diameter of 0.1 to 0.5 µm and not containing Cu is 1 × 10 ⁶ particles / mm 2 or less

It is preferable that the aluminum alloy plate of one embodiment has a circle equivalent diameter of 0.1 to 0.5 µm, and the number density of the intermetallic compounds not containing Cu is 1 × 10 ⁶ pieces / mm 2 or less. The intermetallic compound not containing Cu tends to have a decrease in press formability and stress corrosion cracking resistance when the equivalent circle diameter is more than 0.5 μm or the number density is more than 1 × 10 ⁶ / mm 2 to be. Moreover, when the circle equivalent diameter of the intermetallic compound which does not contain Cu is less than 0.1 micrometer, moldability is favorable, but stress corrosion cracking resistance tends to fall. For this reason, it is preferable that the number equivalent density of the intermetallic compound which has a circle equivalent diameter of 0.1-0.5 micrometer and does not contain Cu is 1x10 <^6> / mm <2> or less. In addition, the lower limit of the number density of the intermetallic compound not containing Cu is not particularly limited, but is preferably 0.5 × 10 ⁴ pieces / mm ² from the viewpoint of press formability. In addition, the "circle equivalent diameter" as used herein means the diameter (circle equivalent diameter) when the area of the observed particle is converted into a circle equivalent.

(ii) The circle equivalent diameter is 0.3-4 µm, and the number density of intermetallic compounds containing Cu is 1 × 10 ⁴ particles / mm 2 or more.

It is preferable that the aluminum alloy plate of one Embodiment has a circle equivalent diameter of 0.3-4 micrometers, and the number density of the intermetallic compound containing Cu is 1x10 <^4> / mm <2> or more. When the intermetallic compound containing Cu has a circle equivalent diameter of less than 0.3 µm, or a number density of less than 1 × 10 ⁴ particles / mm 2, the moldability is good, but for the grain boundary of the β phase (Al ₃ Mg ₂ ) This is because precipitation suppression cannot be sufficiently obtained, and stress corrosion cracking resistance tends to decrease. Moreover, when the circle equivalent diameter of the intermetallic compound containing Cu exceeds 4 micrometers, press moldability tends to deteriorate. For this reason, it is preferable that the number equivalent density of the intermetallic compound containing Cu is 0.3-4 µm and the circle equivalent diameter is 1 × 10 ⁴ pieces / mm 2 or more. The upper limit of the number density of intermetallic compounds containing Cu is not particularly limited, but is preferably 7 × 10 ⁵ pieces / mm ² from the viewpoint of press formability. In addition, the circle equivalent diameter and the number density of the intermetallic compounds present in the aluminum alloy plate can be measured by analyzing the observation picture obtained by observing a thin film sample made of the aluminum alloy plate with a transmission electron microscope. In addition, whether the observed precipitate is an intermetallic compound containing Cu or an intermetallic compound not containing copper is obtained by performing elemental analysis of individual precipitates using an elemental analysis device provided in a transmission electron microscope. I can sympathize. In addition, the circle equivalent diameter and the number density of the intermetallic compound containing Cu and the intermetallic compound not containing copper are the manufacturing conditions in which the solid state and precipitation state of the intermetallic compound, such as heat treatment during production, change (process or process. ), It can be controlled by manufacturing an aluminum alloy plate by a manufacturing method described later.

(III) Manufacturing method of aluminum alloy plate

Next, a preferred embodiment of the method for manufacturing an aluminum alloy plate of one embodiment will be described below.

It is especially important for the method for manufacturing an aluminum alloy plate according to one embodiment to control the cooling rate from the time when the ingot is subjected to the homogenization treatment, and the starting temperature of hot rolling performed thereafter in an appropriate range.

First, the above composition (in mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less) Then, the aluminum alloy having a balance consisting of Al and unavoidable impurities) is melted according to a conventional method, and a typical casting method such as a continuous casting method or a semi-continuous casting method is timely selected and cast. Then, the obtained ingot is subjected to a homogenization treatment at a first temperature within the range of 490 to 580 ° C, preferably 500 to 570 ° C. If the first temperature is less than 490 ° C, segregation of the added elements formed at the time of casting is not resolved, and there is a fear that sufficient moldability may not be obtained. If it is more than 580 ° C, process fusion occurs during processing. This is because there is a risk of cracking during hot rolling. The treatment time of the homogenization treatment is not particularly limited, and can be, for example, in the range of 0.5 hour or more and 24 hours or less.

Next, after subjecting the ingot to the above homogenization treatment, the average cooling rate, more preferably, to a second temperature in the range of 430 to 500 ° C, preferably in the range of 440 to 490 ° C, and further lower than the first temperature Preferably, the average cooling rate measured at the 1/4 thickness position of the ingot is cooled within a range of 500 to 3000 ° C / h, and then hot rolling is started while maintaining the second temperature. Here, the formation of the intermetallic compound containing Cu has the effect of improving the stress corrosion cracking resistance, while the formation of the intermetallic compound not containing Cu has the effect of lowering the stress corrosion cracking resistance, When the average cooling rate is more than 3000 ° C / h, the formation of intermetallic compounds containing Cu tends to be hindered and the stress corrosion cracking tends to decrease, and if the average cooling rate is less than 500 ° C / h , The formation of intermetallic compounds that do not contain Cu is promoted, and stress corrosion cracking tends to decrease. Here, the measurement position of the average cooling rate was set to "1/4 thickness position" because the temperature history of the 1/4 thickness position has a great influence on the performance of the material. In addition, the reason for limiting the second temperature to within the range of 430 to 500 ° C is that if the second temperature is less than 430 ° C, there is a possibility that a defect in curling occurs during hot rolling, and if the second temperature is greater than 500 ° C, This is because there is a risk of cracking during hot rolling. For this reason, in one embodiment, after subjecting the ingot to the above homogenization treatment, the average cooling rate is in the range of 500 to 3000 ° C / h to a second temperature within the range of 430 to 500 ° C and lower than the first temperature. After cooling, hot rolling is started at the second temperature.

After the hot rolling, it is wound at a third temperature in the range of 320 to 380 ° C, preferably in the range of 340 to 360 ° C, and then cold rolling and final annealing are sequentially performed. The reason for limiting the coiling temperature to a third temperature in the range of 320 to 380 ° C is that if the third temperature is less than 320 ° C, recrystallized structures are not obtained after hot rolling, and surface defects (stripe in the rolling direction) are caused after press forming. This is because there is a fear of occurrence, and if the third temperature is higher than 380 ° C, crystal grains may become coarse after hot rolling, and surface roughness may occur.

The above-mentioned is only showing some embodiments of this invention, and various changes can be added in the claims.

Example

Hereinafter, examples of one embodiment will be described.

The aluminum alloy having the composition shown in Table 1 was dissolved, and was compacted by DC casting. The obtained ingot (thickness 30 mm, width 175 mm) was heated to 560 ° C. (first temperature), held at this first temperature for 4 hours, and then the ingot from the first temperature to the second temperature shown in Table 2 After cooling the temperature range at the average cooling rate shown in Table 2 and holding it at the second temperature for 15 minutes, hot rolling was started at the second temperature (hot rolling starting temperature) to obtain a 4 mm thick plate material. The coiling temperature (third temperature) after hot rolling was 360 ° C. Next, this plate material was cold-rolled to a thickness of 1 mm, and then heated in a salt bath at 540 ° C. for 30 seconds, and subjected to a softening treatment (final annealing treatment) forcibly air-cooled with a fan to near room temperature. By the above steps, aluminum alloy plates of Examples and Comparative Examples were produced.

(Test Methods)

[Measurement method of crystal grain size]

For each of the prepared aluminum alloy plates, the crystal grain size was measured. As a method of confirmation, a sample was taken from the center of the width of the aluminum alloy plate, the grain structure was photographed on a rolled surface, and in the field of view of 3 mm x 3 mm, 5 pieces were equally spaced in the vertical direction and the horizontal direction. A straight line was drawn, and the crystal grain size was measured by a sectioning method, and the average value of the measured crystal grain size was calculated as the average grain size (µm). In this example, those having a crystal grain size of less than 50 µm were passed, and those having a size of 50 µm or more were rejected (surface roughness occurred).

[Calculation method of number density of intermetallic compounds]

For each of the prepared aluminum alloy plates, the central portion of the section parallel to the rolling surface from the central portion of the plate width was observed by a transmission electron microscope (TEM) at a magnification of 10,000 times using JEM-2010 manufactured by Nippon Electronics Co., Ltd. It is the value which measured the area of the intermetallic compound in the obtained image using the image analysis software "Winroof", and evaluated it as the diameter (equivalent equivalent diameter) when converted into a circle equivalent. In addition, whether or not the compound contains Cu was analyzed using EDS (Energy Dispersive X-ray Spectroscopy). Number density of intermetallic compounds not containing Cu having a circle equivalent diameter of 0.1 to 0.5 μm (pieces / mm 2) and Number density of intermetallic compounds containing Cu having a circle equivalent diameter of 0.3 to 4 μm (pieces / mm 2) ). Observation was carried out in three fields of view, and an average value was adopted.

[Tensile Characteristics]

For each of the produced aluminum alloy plates, JIS No. 5 test pieces were cut out in a direction perpendicular to the rolling direction, and tensile strength (㎫), proof stress (㎫), and elongation at break (%) were measured by a tensile test. In addition, in the present Example, those having a tensile strength of 240 MPa or more were passed, and those having a tensile strength of less than 240 MPa were rejected, and those having a tensile strength of 100 MPa or more were passed, and those having a tensile strength of less than 100 MPa were rejected.

[Press formability]

In order to investigate the press formability, a stretch molding test and a drawing molding test were performed.

The lengthwise forming test was performed by cutting a square blank having a side of 120 mm from the center of the width of each of the aluminum alloy plates produced, using a die formed with beads by an Ericsen tester, and punching with a diameter of 50 mm. It carried out on condition of a blank holding force of 40 kN and a molding speed of 2.0 mm / s, and measured the stretch height (mm) of a limit in which no cracking occurred, and the press formability was evaluated from the measured value of the stretch height.

In the drawing molding test, a 110 mm-diameter disk was formed from each of the manufactured aluminum alloy plates, a low-viscosity lubricant was applied as a test material, and a lock bead was not formed on the die by using an Ericsen tester. Using a flat-head punch of 50 mm, a blank holding force of 10 kN and a molding speed of 2.0 mm / s were performed to measure the drawing height (mm) of the limit at which cracking does not occur, and from the measured value of the drawing height. The press formability was evaluated.

In addition, in this embodiment, evaluation of the press formability, in the draw moldability, passed that the draw height was 17 mm or more, and rejected that it was less than 17 mm, and in deep drawing, passed the drawing height of 15 mm or more. , What was less than 15 mm was rejected.

[Stress corrosion cracking resistance]

The stress corrosion cracking resistance is subjected to a sensitizing treatment for cold-rolling the test piece collected from the center of the width of each of the prepared aluminum alloy plates at a processing rate of 30%, and then performing heat treatment at 120 ° C. for 7 days. The chromic acid solution (CrO _{3 in} 1 liter of pure water) was heated to 95 ° C. under a stress load under which the specimen subjected to the sensitization treatment was bent into a U-shape having a bending radius of 2 mm and 3 mm, and both ends of the U-shape were constrained. 36 g, K ₂ Cr ₂ O ₇ : 30 g and NaCl: 3 g of an aqueous solution) to measure the time until stress corrosion cracking occurs, and cracks occur within 24 hours at a bending radius of 2 mm. The case was set to "x", the case where no cracks occurred for 24 hours, "○", and the case where no cracks occurred for 96 hours was set to "◎".

Table 3 shows the evaluation results of tensile properties, press formability, and stress corrosion cracking resistance of the aluminum alloy sheet produced in this example.

From the evaluation results shown in Table 3, all of Examples 1 to 23 of the present invention had a high tensile strength of 240 MPa or more, a draw height of 17 mm or more, a drawing height of 15 mm or more, and excellent stress corrosion cracking resistance. On the other hand, all of Comparative Examples 1 to 10 and 17 to 19 having compositions outside the appropriate range of the present invention, and Comparative Examples 11 to 16 manufactured under the manufacturing conditions outside the appropriate range of the present invention are all tensile properties, press formability and stress resistance. At least one of the corrosion cracking properties was inferior.

Industrial availability

The aluminum alloy plate of one embodiment has high strength, good press formability, and excellent stress corrosion cracking resistance. In particular, in addition to members and parts used for various automobiles, such as automobile body seats and body panels, ships It is suitable for use in materials such as parts and parts used in aircraft, aircraft, building materials, structural materials, and various other mechanical devices, household appliances, and parts thereof, and has great industrial value.

Claims (7)

In mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50% and Mn: more than 0.05% and containing 0.35% or less, the balance is Al and An aluminum alloy plate having a composition composed of unavoidable impurities. According to claim 1,
The aluminum alloy plate characterized in that the equivalent circle diameter is 0.1 to 0.5 µm, and the number density of the intermetallic compound not containing Cu is 1 × 10 ⁶ / mm 2 or less. According to claim 1,
An aluminum alloy plate having a circle equivalent diameter of 0.3 to 4 µm, and the number density of intermetallic compounds containing Cu is 1 × 10 ⁴ particles / mm 2 or more. According to claim 1,
Cu: Aluminum alloy plate characterized in that it is 0.13 to 0.35 mass%. According to claim 1,
The said composition further contains 1 or 2 types of Ti: 0.05 mass% or less and B: 0.05 mass% or less, The aluminum alloy plate characterized by the above-mentioned. In mass%, Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50% and Mn: more than 0.05% and containing 0.35% or less, the balance is Al and As a method of manufacturing an aluminum alloy plate having a composition consisting of inevitable impurities,
The ingot obtained by casting the aluminum alloy material having the above composition is subjected to a homogenization treatment at a first temperature in the range of 490 to 580 ° C, and thereafter, a second in the range of 430 to 500 ° C and lower than the first temperature After cooling the temperature to an average cooling rate in the range of 500 to 3000 ° C / h, hot rolling is started while maintaining the second temperature, and then wound up at a third temperature in the range of 320 to 380 ° C, after which , Cold rolling and final annealing treatment are sequentially performed. The method of claim 6,
The first temperature is in the range of 500 to 570 ° C,
The second temperature is in the range of 440 ~ 490 ℃,
A method of manufacturing an aluminum alloy plate, wherein the third temperature is in the range of 340 to 360 ° C.