JP2017052989A - Structural aluminum alloy plate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structural aluminum alloy plate excellent in both of strength and ductility and a method of producing the same.SOLUTION: A structural aluminum alloy plate has chemical components comprising, in mass%, Zn: 7.0% or more and 12.0% or less, Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more and 3.0% or less and Zr: 0.05% or more and 0.30% or less, with Si: 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3% or less and Cr: 0.3% or less, and with the balance being Al and inevitable impurities. The structural aluminum alloy plate has a tensile strength of 680 MPa or more, a proof stress of 620 MPa or more, and a breaking elongation of 10% or more.SELECTED DRAWING: None

Description

  The present invention relates to a structural aluminum alloy plate and a method for producing the same.

  Al-Zn-Mg-Cu (aluminum-zinc-magnesium-copper) -based aluminum alloy plates are light and high in strength, and are therefore frequently used as structural materials in the fields of aircraft, spacecrafts, vehicles, and the like. In recent years, there has been a demand for further weight reduction of structural materials used in these fields. In order to meet such requirements, studies have been made to further increase the strength of aluminum alloy plates (for example, Patent Documents 1 to 3).

Japanese Patent No. 4285916 Patent No. 472159 Japanese Patent No. 5083816

The Al—Zn—Mg—Cu-based aluminum alloy has a strength by dissolving the crystallized product of η phase (MgZn ₂ ) and S phase (Al ₂ CuMg) present in the ingot by solution treatment. Can be improved. In order to dissolve more η phase and the like, it is preferable to increase the treatment temperature in the solution treatment.

  However, if the treatment temperature in the solution treatment is simply increased, the η phase or S phase may melt during the treatment, and porosity may be formed inside the plate. When the porosity inside the plate increases, the ductility of the plate decreases, which is not preferable as a structural material.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a structural aluminum alloy plate excellent in both strength and ductility and a method for producing the structural aluminum alloy plate.

One embodiment of the present invention is Zn (zinc): 7.0% to 12.0% (mass%, the same applies hereinafter), Mg (magnesium): 1.5% to 4.5%, Cu (copper) : 1.0% to 3.0% and Zr (zirconium): 0.05% to 0.30%, Si (silicon): 0.5% or less, Fe (iron): 0.5 % Or less, Ti (titanium): 0.5% or less, Mn (manganese): 0.3% or less, and Cr (chromium): 0.3% or less, and the balance from Al (aluminum) and inevitable impurities Has a chemical component
The tensile strength is 680 MPa or more,
Yield strength is 620 MPa or more,
The structural aluminum alloy sheet has a breaking elongation of 10% or more.

Other aspects of the present invention include Zn: 2.0% or more and less than 7.0% (mass%, the same applies hereinafter), Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more, and 3. 0% or less and Zr: 0.05% or more and 0.30% or less, Si: 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3% And Cr: restricted to 0.3% or less, with the remainder having chemical components consisting of Al and inevitable impurities,
The tensile strength is 600 MPa or more,
Yield strength is 550 MPa or more,
The structural aluminum alloy sheet has a breaking elongation of 10% or more.

Still another embodiment of the present invention includes Zn: 2.0% or more and 12.0% or less (mass%, the same applies hereinafter), Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more 3 0.0% or less and Zr: 0.05% or more and 0.30% or less, Si: 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3 % Or less and Cr: 0.3% or less, the ingot is prepared having a chemical component consisting of Al and inevitable impurities in the balance,
Hot rolling is performed on the ingot to produce a hot rolled plate,
The hot-rolled sheet is heated so that the average rate of temperature rise from 5 to 20 ° C./h until reaching the solution treatment temperature selected from the range of 475 to 500 ° C. after reaching 300 ° C. And
Hold the temperature of the hot rolled plate at the solution treatment temperature for 0.5 to 10 hours to perform solution treatment,
Then, water quenching the hot rolled plate,
Next, the present invention is a method for producing a structural aluminum alloy plate, wherein the hot-rolled plate is subjected to artificial aging treatment.

  In the method for producing the structural aluminum alloy plate (hereinafter simply referred to as “aluminum plate”), the hot-rolled plate is heated so that the average heating rate is in the specific range. Thereby, the said solution treatment temperature can be set to a temperature higher than before, suppressing the melt | dissolution of the crystallized substance of the (eta) phase and S phase which exist in the said hot rolled sheet. Therefore, the said manufacturing method can reduce the porosity derived from melting | dissolving, such as (eta) phase. Moreover, the said manufacturing method can increase the amount of solid solutions, such as (eta) phase, conventionally.

  As a result, the manufacturing method can produce the aluminum plate excellent in both strength and ductility.

  The said aluminum plate manufactured by applying the said manufacturing method is excellent in both intensity | strength and ductility compared with the aluminum plate manufactured by the conventional manufacturing method. For example, by applying the above production method to the production of an Al—Zn—Mg—Cu-based aluminum alloy plate having a chemical component within a general range, a tensile strength of 600 MPa or more, a yield strength of 550 MPa or more, and 10% or more It is possible to easily obtain the aluminum plate having the elongation at break.

  Moreover, the aluminum plate having a tensile strength of 680 MPa or more, a yield strength of 620 MPa or more, and a breaking elongation of 10% or more can be easily obtained by further increasing the Zn content from the general range. Since these aluminum plates are excellent in both strength and ductility, they are suitable as structural materials for aircraft, spacecrafts, vehicles, and the like.

  The reason for limiting the chemical components in the aluminum plate will be described below. The aluminum plate contains Zn, Mg, Cu, and Zr as essential components.

(1) Zn (zinc): 2.0 to 12.0%
Zn has the effect | action which improves the intensity | strength of the said aluminum plate. By setting the Zn content to 2.0% or more, the strength of the aluminum plate can be improved. From the same viewpoint, the Zn content is preferably 7.0% or more, and more preferably 8.0% or more.

  When the Zn content is excessively large, Zn-Mg based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Zn content is set to 12.0% or less. From the same viewpoint, the Zn content is preferably 11.0% or less.

(2) Mg (magnesium): 1.5 to 4.5%
Mg has the effect | action which improves the intensity | strength of the said aluminum plate. By setting the Mg content to 1.5% or more, the strength of the aluminum plate can be improved.

  When the Mg content is excessively large, Zn-Mg-based crystallized substances and precipitates, or Al-Mg-Cu-based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. There is. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Mg content is set to 4.5% or less. From the same viewpoint, the Mg content is preferably 3.5% or less.

(3) Cu (copper): 1.0-3.0%
Cu has the effect | action which improves the intensity | strength of the said aluminum plate. By setting the Cu content to 1.0% or more, the strength of the aluminum plate can be improved.

  When the content of Cu is excessively large, Al-Cu-based crystallized substances and precipitates, or Al-Mg-Cu-based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. There is. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Cu content is set to 3.0% or less. From the same viewpoint, the Cu content is preferably 2.5% or less.

(4) Zr (zirconium): 0.05 to 0.30%
Zr has the effect | action which improves the intensity | strength of the said aluminum plate by suppressing the recrystallization at the time of solution treatment. By making the content of Zr 0.05% or more, the strength of the aluminum plate can be improved.

  When the Zr content is excessively large, Al-Zr-based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Zr content is set to 0.30% or less. From the same viewpoint, the Zr content is preferably 0.20% or less.

  The aluminum plate may contain Si, Fe, Ti, Mn and Cr as optional components. In addition, these components may be mixed when producing the said aluminum plate using a recycled material.

(5) Si (silicon): 0.5% or less When the Si content is excessively large, Al-Fe-Si-based crystallized substances and precipitates, or Si-based crystallized substances and precipitates are present. There is a possibility that a large amount is formed in the aluminum plate. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Si content is set to 0.5% or less. From the same viewpoint, the Si content is preferably regulated to 0.4% or less.

(6) Fe (iron): 0.5% or less When the content of Fe is excessively large, Al-Fe-Si-based crystallized products and precipitates, or Al-Fe-based crystallized products and precipitates There is a possibility that a large amount of objects are formed in the aluminum plate. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Fe content is set to 0.5% or less. From the same viewpoint, the Fe content is preferably regulated to 0.35% or less.

(7) Ti (titanium): 0.5% or less When the Ti content is excessively large, Al-Ti-based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. . These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Ti content is set to 0.5% or less. From the same viewpoint, the Ti content is preferably regulated to 0.35% or less.

(8) Mn (manganese): 0.3% or less In the case where the content of Mn is excessively large, Al-Mn-based crystallized substances and precipitates, or Al-Fe-Si-Mn-based crystallized substances. And a large amount of precipitates may be formed in the aluminum plate. These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, from the viewpoint of avoiding a decrease in ductility of the aluminum plate, the Mn content is set to 0.3% or less. From the same viewpoint, it is preferable to regulate the Mn content to 0.2% or less.

(9) Cr (chromium): 0.3% or less When the Cr content is excessively large, Al-Cr-based crystallized substances and precipitates may be formed in a large amount in the aluminum plate. . These precipitates and crystallized substances are not preferable because they reduce the ductility of the aluminum plate. Therefore, the content of Cr is set to 0.3% from the viewpoint of avoiding the decrease in ductility of the aluminum plate. From the same viewpoint, the Cr content is preferably regulated to 0.2% or less.

  Next, the manufacturing method of the said aluminum plate is demonstrated. In the manufacturing method, after preparing an ingot having the specific chemical component, the aluminum plate is subjected to homogenization treatment, hot rolling, solution treatment, water quenching, and artificial aging treatment in order on the ingot. Can be produced. The homogenization treatment, hot rolling, water quenching and artificial aging treatment can be performed under conventionally known conditions.

  After hot rolling to produce a hot rolled sheet from the ingot, the hot rolled sheet is heated to raise the temperature in order to perform a solution treatment. At this time, the temperature may be increased under any conditions until the temperature of the hot-rolled sheet reaches 300 ° C.

  After the temperature of the hot-rolled sheet reaches 300 ° C., heating is performed so that the average rate of temperature rise is within the range of 5 to 20 ° C./h until the solution treatment temperature is reached. Thereby, the η phase and the S phase can be gradually dissolved in the mother phase while the hot rolled sheet is being heated. As a result, the formation of porosity due to the melting of the η phase or the S phase can be suppressed.

  When the average heating rate is less than 5 ° C./h, coarse crystal grains are likely to be generated. This coarse crystal grain is not preferable because it causes a decrease in strength of the aluminum plate. In this case, the time until the solution treatment temperature is reached becomes excessively long, which leads to a decrease in productivity. From the viewpoint of avoiding these problems, the average heating rate is set to 5 ° C./h or more.

  On the other hand, when the average temperature increase rate exceeds 20 ° C./h, the η phase and the S phase are rapidly melted during the temperature increase of the hot-rolled sheet. And since porosity is formed in the location where the η phase or S phase disappeared by melting, the ductility of the aluminum plate is lowered.

  The solution treatment temperature is preferably near the melting point of the η phase and the S phase. The melting point of the η phase is usually about 470 to 480 ° C., and the melting point of the S phase is usually about 485 to 500 ° C. Therefore, by selecting the solution treatment temperature from the range of 475 to 500 ° C., both the η phase and the S phase can be dissolved in the matrix phase.

  When the solution treatment temperature is less than 475 ° C., the solid solution amount of the η phase and the S phase becomes insufficient, so that the strength of the aluminum plate is lowered. Therefore, from the viewpoint of sufficiently dissolving the η phase and the S phase, the solution treatment temperature is set to 475 ° C. or higher. From the same viewpoint, the solution temperature is more preferably 480 ° C. or higher.

  When the solution treatment temperature exceeds 500 ° C., the solution treatment temperature exceeds the solidus temperature of the mother phase, so that the mother phase may partially dissolve. In order to avoid this problem, the solution treatment temperature is set to 500 ° C. or lower. From the same viewpoint, the solution temperature is more preferably 495 ° C. or lower.

  The solution treatment is performed by holding the temperature for 0.5 to 10 hours after the temperature of the hot-rolled sheet reaches the solution treatment temperature. By setting the holding time in the solution treatment to the above specific range, both the η phase and the S phase can be sufficiently dissolved in the matrix phase.

  When the holding time is less than 0.5 hour, the solid solution amount of the η phase and the S phase becomes insufficient, so that the strength of the aluminum plate is lowered. Therefore, from the viewpoint of sufficiently dissolving the η phase and the S phase, the holding time is 0.5 hours or more. From the same viewpoint, the holding time is preferably set to 1 hour or longer.

  When the holding time exceeds 10 hours, coarse crystal grains are likely to be generated. Further, in this case, the time required for the solution treatment becomes excessively long, resulting in a decrease in productivity. From the viewpoint of avoiding these problems, the holding time is 10 hours or less. From the same viewpoint, the holding time is preferably 8 hours or less.

Example 1
This example is an example of an aluminum plate produced by changing various chemical components. In this example, first, ingots of aluminum alloys A to L having chemical components shown in Table 1 were produced by DC casting. In Table 1, “Bal.” Indicates a residual component (Balance).

These ingots were heated at a temperature of 470 ° C. for 10 hours for homogenization. Subsequently, the ingot after the homogenization treatment was hot-rolled to obtain a hot-rolled plate having a thickness of 20 mm. Hot rolling was started with the temperature of the ingot being 400 ° C. The strain rate in hot rolling was 0.3 s ⁻¹ and the total rolling reduction was 96%.

  Next, the hot rolled plate was heated to 480 ° C. The hot-rolled sheet was heated so that the average rate of temperature increase from when the temperature of the hot-rolled sheet reached 300 ° C. until it reached 480 ° C. was 5 ° C./h.

  After the temperature of the hot-rolled sheet reached 480 ° C., the temperature was maintained for 1 hour to perform solution treatment. Thereafter, the hot-rolled sheet was water-quenched and cooled to 75 ° C. or lower in 50 seconds. After water quenching, the hot-rolled sheet was heated again, and an artificial aging treatment was performed while maintaining a temperature of 120 ° C. for 24 hours. Thus, test materials 1 to 12 shown in Table 2 were obtained.

  The tensile test of the test materials 1-12 obtained by the above was done according to the method prescribed | regulated to JISZ2241. The specimen used for the tensile test was collected from each test material so that the tensile direction was parallel to the rolling direction. Table 2 shows the values of tensile strength, yield strength and elongation at break obtained by the tensile test.

  As shown in Table 1 and Table 2, the test materials 1 to 4 are: Zn: 7.0% to 12.0%, Mg: 1.5% to 4.5%, Cu: 1.0% More than 3.0% or less and Zr: 0.05% or more and 0.30% or less, Si: 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0 0.3% or less and Cr: 0.3% or less, and the balance is made of aluminum alloys A to D having chemical components composed of Al and inevitable impurities. And the test materials 1-4 are produced on the conditions from which the average temperature increase rate before solution treatment, solution treatment temperature, and holding time become in the said specific range. As a result, the test materials 1 to 4 exhibited a tensile strength of 680 MPa or more, a yield strength of 620 MPa or more, and a breaking elongation of 10% or more.

The test material 5 is made of an aluminum alloy E having a Zn content exceeding 12.0%. Therefore, the breaking elongation of the test material 5 was less than 10%.
The test material 6 is made of an aluminum alloy F having a Zn content of less than 7.0%. Therefore, the tensile strength and proof stress of the test material 6 were less than the specific range. Further, since the aluminum alloy F has an Fe content exceeding 0.5%, the breaking elongation of the test material 6 was less than 10%. In addition, the tensile strength and proof stress of the test material 6 are favorable values as an aluminum plate whose Zn content is 2.0% or more and less than 7.0%.

The test material 7 is made of an aluminum alloy G in which the Mg content exceeds 4.5% by mass. Therefore, the breaking elongation of the test material 7 was less than 10%.
The test material 8 is made of an aluminum alloy H having a Mg content of less than 1.5% by mass. Therefore, the tensile strength and proof stress of the test material 8 were less than the specific range.

The test material 9 is made of an aluminum alloy I having a Cu content exceeding 3.0% by mass. Therefore, the breaking elongation of the test material 9 was less than 10%.
The test material 10 is made from an aluminum alloy J having a Cu content of less than 1.0 mass%. Therefore, the tensile strength and proof stress of the test material 10 were less than the specific range.

The test material 11 is made of an aluminum alloy K having a Zr content of less than 0.05% by mass. Therefore, the tensile strength and proof stress of the test material 11 were less than the specific range.
The test material 12 is made of an aluminum alloy L in which the Fe content exceeds 0.5% by mass. Therefore, the breaking elongation of the test material 12 was less than 10%.

  As can be seen from the above results, the test was made with the chemical components in the specific range, and the conditions for the average heating rate, solution treatment temperature, and holding time before the solution treatment were within the specific range. Materials 1 to 4 became aluminum plates excellent in both strength and ductility.

(Example 2)
In this example, the above production method is applied to an Al—Zn—Mg—Cu-based aluminum alloy having a general component range. In this example, after producing ingots of aluminum alloys M to V having the chemical components shown in Table 3, homogenization treatment, hot rolling, solution treatment, water quenching and artificial quenching were performed under the same conditions as in Example 1. An aging treatment was performed. Thus, test materials 13 to 22 shown in Table 4 were produced. And the tension test of the test materials 13-22 was done by the method similar to Example 1. FIG. Table 4 shows the values of tensile strength, yield strength and elongation at break obtained by the tensile test. In Table 3, “Bal.” Indicates a residual component (Balance).

  As shown in Table 3 and Table 4, the test materials 13 to 17 were Zn: 2.0% or more and less than 7.0%, Mg: 1.5% or more and 4.5% or less, Cu: 1.0% More than 3.0% or less and Zr: 0.05% or more and 0.30% or less, Si: 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0 .3% or less and Cr: 0.3% or less, and the balance is made of aluminum alloys M to Q having chemical components composed of Al and inevitable impurities. And the test materials 13-17 are produced on the conditions from which the average temperature increase rate before solution treatment, solution treatment temperature, and holding time become in the said specific range. As a result, the test materials 13 to 17 exhibited a tensile strength of 600 MPa or more, a proof stress of 550 MPa or more, and a breaking elongation of 10% or more.

  The test material 18 is made of an aluminum alloy R having a Zn content of less than 2.0%. Therefore, the tensile strength and proof stress of the test material 18 were less than the specific range.

The test material 19 is made of an aluminum alloy S having a Si content exceeding 0.5% by mass. Therefore, the breaking elongation of the test material 19 was less than 10%.
The test material 20 is made of an aluminum alloy T having a Ti content exceeding 0.5% by mass. Therefore, the breaking elongation of the test material 20 was less than 10%.

The test material 21 is made of an aluminum alloy U having a Mn content exceeding 0.3% by mass. Therefore, the breaking elongation of the test material 21 was less than 10%.
The test material 22 is made of an aluminum alloy V having a Cr content exceeding 0.3% by mass. Therefore, the breaking elongation of the test material 22 was less than 10%.

  As can be seen from the above results, even in an Al—Zn—Mg—Cu-based aluminum alloy having a chemical component in a general range, the average heating rate, solution treatment temperature, and holding time before solution treatment are specified as described above. By producing an aluminum plate under the conditions within the above range, it was possible to improve the strength compared to the conventional one while maintaining high ductility.

(Example 3)
In this example, the average temperature increase rate before the solution treatment, the solution treatment temperature, and the retention time in the solution treatment are variously changed. In this example, first, an ingot having a thickness of 500 mm and a width of 500 mm was produced by DC casting. The aluminum alloy constituting this ingot is: Zn: 9.8%, Mg: 2.4%, Cu: 1.4%, Zr: 0.13%, Si: 0.25%, Fe: 0.12 %, Ti: 0.03%, Mn: 0.02% and Cr: 0.01%, with the balance having chemical components consisting of inevitable impurities and aluminum.

  Subsequently, the obtained ingot was homogenized and hot-rolled in the same manner as in Example 1 to produce a hot-rolled plate having a thickness of 20 mm.

  This hot-rolled sheet was heated to a solution treatment temperature and then subjected to a solution treatment. Table 5 shows the average rate of temperature increase from 300 ° C. to the solution treatment temperature, the treatment temperature in the solution treatment, and the holding time.

  Thereafter, water quenching and artificial aging treatment of the hot-rolled sheet were performed in the same manner as in Example 1. Thus, test materials 23 to 32 shown in Table 5 were obtained.

  The tensile test of the obtained test materials 23 to 28 and test materials 30 to 32 was performed in the same manner as in Example 1. The results are shown in Table 5. In addition, since the solution treatment temperature of the test material 29 exceeded 500 ° C., partial melting occurred during the solution treatment. Therefore, a test piece for a tensile test could not be collected from the test material 29, and a tensile test could not be performed.

  As can be seen from Table 5, the test material was prepared under the conditions that the chemical components in the specific range were used and the average temperature rising rate, solution treatment temperature and holding time before the solution treatment were within the specific range. Nos. 23 to 26 were aluminum plates excellent in both strength and ductility.

In the test material 27, the average rate of temperature increase from 300 ° C. to the solution treatment temperature exceeded 20 ° C./h. Therefore, the breaking elongation of the test material 27 was less than 10%.
The test material 28 had an average rate of temperature increase from 300 ° C. to the solution treatment temperature of less than 5 ° C./h. Therefore, the tensile strength and proof stress of the test material 28 were less than the specific range.

The test material 30 had a solution treatment temperature of less than 475 ° C. Therefore, the tensile strength and proof stress of the test material 30 were less than the specific range.
The test material 31 had a retention time in the solution treatment exceeding 10 hours. Therefore, the tensile strength and proof stress of the test material 31 were less than the specific range.
The test material 32 had a retention time in the solution treatment of less than 0.5 hours. Therefore, the tensile strength and proof stress of the test material 32 were less than the specific range.

Claims (3)

Zn: 7.0% or more and 12.0% or less (mass%, the same applies hereinafter), Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more and 3.0% or less, and Zr: 0. 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3% or less, and Cr: 0.3% Regulated below, with the remainder having chemical components consisting of Al and inevitable impurities,
The tensile strength is 680 MPa or more,
Yield strength is 620 MPa or more,
A structural aluminum alloy plate having an elongation at break of 10% or more. Zn: 2.0% or more and less than 7.0% (mass%, the same applies hereinafter), Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more and 3.0% or less, and Zr: 0.00%. 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3% or less, and Cr: 0.3% Regulated below, with the remainder having chemical components consisting of Al and inevitable impurities,
The tensile strength is 600 MPa or more,
Yield strength is 550 MPa or more,
A structural aluminum alloy plate having an elongation at break of 10% or more. Zn: 2.0% or more and 12.0% or less (mass%, the same applies hereinafter), Mg: 1.5% or more and 4.5% or less, Cu: 1.0% or more and 3.0% or less, and Zr: 0. 0.5% or less, Fe: 0.5% or less, Ti: 0.5% or less, Mn: 0.3% or less, and Cr: 0.3% Prepared ingots having chemical components consisting of Al and inevitable impurities, the remainder being regulated below,
Hot rolling is performed on the ingot to produce a hot rolled plate,
The hot-rolled sheet is heated so that the average rate of temperature rise from 5 to 20 ° C./h until reaching the solution treatment temperature selected from the range of 475 to 500 ° C. after reaching 300 ° C. And
Hold the temperature of the hot rolled plate at the solution treatment temperature for 0.5 to 10 hours to perform solution treatment,
Then, water quenching the hot rolled plate,
Next, a method for producing a structural aluminum alloy sheet, wherein the hot-rolled sheet is subjected to artificial aging treatment.