JP2011106011A - HIGH STRENGTH Al ALLOY FORGED MATERIAL HAVING EXCELLENT CORROSION RESISTANCE AND WORKABILITY AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high strength Al alloy forged material which has no coarse crystal grains in the surface layer part thereof and therefore has a prescribed hardness or more, and has excellent corrosion resistance and workability. <P>SOLUTION: The forged material is composed of Al alloy having an alloy composition containing, by mass, 0.6 to 1.2% Mg, 0.4 to 1.3% Si, 0.03 to 0.8% Cu, 0.04 to 0.5% Fe and 0.005 to 0.10% Ti, and the balance Al with inevitable impurities. In the forged material, Vickers hardness in the optional cross-section thereof is ≥110 HV10, also, the average crystal grain size in the surface layer part thereof is ≤150 μm, and the maximum grain size of intermetallic compounds is <5 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-strength Al alloy forged material excellent in corrosion resistance and workability and a method for producing the same, and in particular, a high-strength Al alloy forged material that can be suitably used as a structural member for a vehicle, and the like. It relates to a method that can be manufactured.

  In recent years, due to increasing environmental awareness, automobiles have been made lighter in order to improve fuel economy. As one of the countermeasures, lightweight Al (aluminum) is used instead of ferrous materials. Alloy materials have been adopted. For example, in the underbody parts of vehicles such as suspensions, the use of those made of Al alloy forging is increasing. In addition, when using an Al alloy forged material for the suspension arm, since it has a complicated product shape, after being formed by hot forging, it is subjected to heat treatment, cutting, etc. Plastic processing or the like is also performed for press-fitting of a bush or mounting of a ball joint. In order to make the mounting part have the strength as designed, there is a demand for an Al alloy material having a homogeneous material structure and strength and causing no problems during processing. In addition, the suspension arm can be used in parts that are used in harsh environments such as mud when the weight of the vehicle is loaded. Good corrosion resistance is also needed.

  By the way, as a high-strength Al alloy forging material used for a vehicle etc. until now, in Unexamined-Japanese-Patent No. 2004-292289 (patent document 1), content of Mg, Si, Mn, and Ti, and Si / Mg In addition, a material has been proposed that contains Cr and / or Zr, regulates the content of these components, and regulates the average particle size and area density of the dispersed particles. However, in this case, after the homogenization treatment, cooling is performed, or in the case of direct forging after the homogenization treatment, the material is cooled to the forging temperature. Therefore, solute atoms are coarse in the material. There is a problem that it is difficult to obtain a uniform material structure depending on the product shape.

  Further, in Japanese Patent Application Laid-Open No. 2005-213529 (Patent Document 2), an aging precipitation element is solidified by plastic working an Al alloy material heated in advance to 400 ° C. or higher with a tool held at −100 to 100 ° C. A method of manufacturing an Al alloy plastic working member that has been melted and maintained in a supersaturated and supercooled state while maintaining a high-density transition as it is has been developed. According to such a method, although sufficient toughness is obtained, the tool temperature is low, so that the fluidity of the material is lowered, and there is a problem that condition management is difficult depending on the product shape.

  Furthermore, in Japanese Patent Application Laid-Open No. 2002-60881 (Patent Document 3), as one of the casting forging methods, a technique for high-temperature forging an Al alloy casting having a predetermined alloy composition using a heated mold is obvious. Has been. And, forging materials obtained by using techniques such as die casting and molten metal forging, because the shape can be designed freely, it is easy to adjust the forging rate according to the final product shape However, when trying to apply a DC-cast material, this material is usually a round bar-shaped cast bar. Depending on the forging shape, the processing rate depends on the part of the forging material to be obtained. It was different and it was difficult to obtain a homogeneous structure.

  In particular, in the conventional 6000 series Al alloy forged material, crystal grains are often coarse in the surface layer portion that gives the surface of the forged material. For this reason, for example, when a bush or a ball joint is attached to a suspension arm, plastic working is performed. If this is applied, orange peel may occur and the surface may become uneven.In addition, the coarse crystal grain portion on the surface layer of the forged material has a lower strength and a large impact. When loaded, there was a risk of starting damage. Therefore, the portion where the crystal grains in such a forged material are coarse had to be removed by cutting or changing the design specifications.

JP 2004-292892 A JP 2005-213529 A JP 2002-60881 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that there are no coarse crystal grains in the surface layer portion of the forged material, and the predetermined hardness or higher. An object of the present invention is to provide a high-strength Al alloy forging material excellent in corrosion resistance and workability and an advantageous production method thereof.

  In the present invention, in order to solve such a problem, Mg: 0.6 to 1.2%, Si: 0.4 to 1.3%, Cu: 0.03 to 0 on a mass basis. 0.8%, Fe: 0.04 to 0.5%, and Ti: 0.005 to 0.10%, and the balance is made of an Al alloy having an alloy composition in which the balance is Al and inevitable impurities. Corrosion resistance, characterized in that the Vickers hardness in any cross section is 110 HV10 or more, the average crystal grain size in the surface layer part is 150 μm or less, and the maximum grain size of the intermetallic compound is less than 5 μm, and A high-strength Al alloy forging material excellent in workability is the gist of the invention.

  In the high-strength Al alloy forging according to the present invention, the Al alloy is based on mass, Mn: 0.01 to 0.9%, Cr: 0.01 to 0.25%, and Zr: One or more of 0.01 to 0.25% can be further contained.

  Further, in the present invention, in order to advantageously obtain such a high-strength Al alloy forging material according to the present invention, the ingot made of the Al alloy obtained by DC casting is heated at a temperature of 30 ° C./hour or more. After heating at a speed of 490 ° C. or higher and lower than 550 ° C. and holding at that temperature for 1 to 20 hours, immediately perform hot forging using a forging die heated to 200 to 500 ° C. Before the temperature of the obtained forged material becomes less than 480 ° C., it is cooled at a cooling rate of 50 ° C./second or more to the temperature of artificial aging, and then heated to 160 to 220 ° C. for 1 to 30 hours. The gist of the present invention is also a method for producing a high-strength Al alloy forging material characterized by performing artificial aging treatment.

  According to the present invention as described above, the Vickers hardness in an arbitrary cross section of the forged material is further improved as compared with the conventional 6000 series Al—Mg—Si based alloy. Is 110 HV10 or more, the average crystal grain size in the surface layer portion of the forging is 150 μm or less, and the maximum grain size of the intermetallic compound is less than 5 μm, and can be suitably used as a structural member for vehicles, corrosion resistance and workability Thus, a high-strength Al alloy forging material having excellent characteristics can be provided, and an Al alloy forging material having such excellent characteristics can be produced industrially advantageously. And the Al alloy forging material can be used suitably as suspension parts, such as a suspension in a vehicle.

It is a figure which shows the forging material manufactured in an Example, Comprising: (a) is the front explanatory drawing, (b) is BB sectional explanatory drawing in (a).

  In short, as a result of repeated studies by the present inventors on the relationship between the alloy components in the extruded materials and forged materials of Al-Mg-Si alloys, strength, corrosion resistance, and material structure, the amount of Mg and the amount of Si are specified. Al alloy with high corrosion resistance, high strength, and homogeneous material structure by adjusting the relationship of the above, further defining the range of Cu amount, Fe amount, Ti amount and controlling the cross-sectional structure by devising the manufacturing conditions It became clear that a forged material can be obtained and its workability can be improved. Specifically, when the Vickers hardness in an arbitrary cross section of the Al alloy forging material is 110HV10 or more and the surface layer portion of the forging material, in other words, the thickness thereof is T, the depth from the surface to T / 4. When the average crystal grain size in the region of the length region is 150 μm or less, problems such as orange peel are advantageously suppressed, and the maximum grain size of the intermetallic compound is less than 5 μm, thereby improving workability. I was able to work effectively.

Here, if the significance and reasons for limitation of the alloy components in the Al alloy that gives the forging material according to the present invention are described, first, Si (silicon) coexists with Mg, and precipitates Mg ₂ Si particles in the matrix. And exhibits the characteristics of improving strength. Therefore, the Si content needs to be in the range of 0.4 to 1.3% by mass. On the other hand, when the Si content is less than 0.4% by mass, sufficient strength is obtained. If it is not obtained and exceeds 1.3% by mass, no improvement in strength can be expected, and the maximum particle size of the intermetallic compound increases. The more preferable content range of this Si is 0.6-1.2 mass%.

Further, Mg (magnesium) coexists with Si and functions to precipitate Mg ₂ Si particles in the matrix and improve the strength of the alloy. The necessary content for this purpose is in the range of 0.6 to 1.2% by mass. On the other hand, if the content is less than 0.6% by mass, sufficient strength cannot be obtained, and 1.2% by mass. If the content exceeds V, deformation resistance increases and problems such as poor forging workability are caused. In addition, the more preferable content range of this Mg is 0.65-1.15 mass%.

  Furthermore, Cu (copper) has a function of improving the strength of the alloy by solid solution in the matrix, and for that purpose, it is necessary to contain it in the range of 0.03 to 0.8 mass%. There is. If the Cu content is less than 0.03% by mass, the effect is not sufficient, and if it exceeds 0.8% by mass, problems such as a decrease in corrosion resistance are caused. A more preferable content range of Cu is 0.05 to 0.75% by mass.

  Furthermore, Fe (iron) has the effect of making the crystal grains fine, and for that purpose, its content needs to be in the range of 0.04 to 0.5 mass%. When the Fe content is less than 0.04% by mass, the effect is not sufficient, and when it exceeds 0.5% by mass, a huge intermetallic compound is formed, and forgeability is reduced. Raise the problem.

  In addition, Ti (titanium) also has an effect of making crystal grains fine, and for that purpose, it needs to be contained within a range of 0.005 to 0.10% by mass. When the content is less than 0.005% by mass, the effect is not sufficient. When the content exceeds 0.10% by mass, a huge intermetallic compound is formed, and forgeability is reduced. Raise the problem.

  In addition to the above-described essential alloy components, the Al alloy used in the present invention may be one or more of Mn (manganese), Cr (chromium), and Zr (zirconium) as necessary. Is added to contribute to the refinement of crystal grains. These Mn, Cr, and Zr play the role of precipitating Al-Mn- (Si) -based, Al-Cr-based, and Al-Zr-based fine compounds in the matrix to form and maintain subcrystalline grains, respectively. Is. The content of these elements is in the range of Mn: 0.01 to 0.9% by mass, Cr: 0.01 to 0.25% by mass, Zr: 0.01 to 0.25% by mass, In the amount range, one kind or a combination of two or more kinds are added. If the content of these elements is less than the respective lower limit, the effect is not sufficient, and if the content exceeds the upper limit, a huge intermetallic compound is formed, causing problems such as a reduction in forgeability. To do.

  The Al alloy according to the present invention is composed of Al and inevitable impurities in addition to the above alloy components. This inevitable impurity is inevitably mixed in the preparation of the target Al alloy, and its content is controlled so that it exists at a known impurity ratio. In general, the total content of such inevitable impurities is 0.15% by mass or less.

  By the way, when producing a forging material according to the present invention comprising an Al alloy having such an alloy composition, first, an ingot comprising an Al alloy having the alloy composition as described above is obtained by DC casting according to a conventional method, and The obtained Al alloy ingot was heated to a temperature of 490 ° C. or more and less than 550 ° C. at a temperature increase rate of 30 ° C./hour or more without performing homogenization treatment, and then at that temperature for 1 to 20 hours. It is held at a high temperature, and then forging starts immediately at that temperature.

  Here, when a sand mold or a die cast ingot is used instead of an ingot obtained by DC casting, a variation in the microstructure of the surface layer is large, so that it is difficult to obtain a homogeneous structure. This causes a problem that makes it difficult to exhibit the characteristics. The homogenization treatment is a heat treatment in which the ingot is kept at a high temperature for a certain period of time and then cooled to homogenize the material structure. During the cooling after this homogenization treatment, the ingot is dissolved in the Al matrix. Since the solute elements that have been deposited are coarsely precipitated, there is a problem that the effect of refining the crystal grains becomes small. Therefore, in the present invention, such a homogenization treatment is not performed. .

  In the present invention, the Al alloy ingot obtained by the DC casting is heated at 30 ° C./hour or more as the heating for forging which is the next step without performing such a homogenization treatment. The temperature was increased to a temperature of 490 ° C. or higher and lower than 550 ° C., and the temperature was maintained at that temperature for 1 to 20 hours. Here, when the rate of temperature increase is less than 30 ° C./hour, the solute element dissolved in the Al matrix phase is coarsely precipitated in the process of temperature increase. Causes problems such as smallness. Note that the upper limit of the rate of temperature increase is generally about 200 ° C./hour from a technical point of view. In addition, if the heating temperature for forging described above is less than 490 ° C., the temperature after forging becomes less than 480 ° C., causing a problem that it is difficult to sufficiently exhibit properties such as strength. Furthermore, when heated to 550 ° C or higher, the graphite lubrication between the mold and the Al material does not function during forging, and the material may not adhere to the mold and may not be manufactured. Provoke. In addition, as such a heating temperature for forging, it is more preferable to adopt within a range of 495 ° C to 545 ° C. Moreover, when the holding time after heating and heating is less than 1 hour, coarse intermetallic compounds produced during casting are likely to remain, and even if the holding time exceeds 20 hours, a good material can be obtained. Industrially, it takes a long time to occupy the furnace and raises the problem of high cost.

  Next, the Al alloy ingot heated and held at such a temperature is immediately cooled to a desired product shape using a forging die heated to a temperature of 200 to 500 ° C. without being cooled. Thus, hot forging is performed. In this hot forging, the same forging operation as in the past is adopted, and for example, forging operations such as roughing, intermediate and finishing can be performed several times depending on the product shape. In this case, the hot forging operation is advanced without reheating during the process. When the temperature of the forging die is less than 200 ° C., the temperature of the surface layer of the material suddenly decreases when the material is deformed in contact with the die. There are problems such as low strength, and at temperatures exceeding 500 ° C., a good material structure can be obtained, but the effect of the graphite-based lubricant used to suppress adhesion between the mold and the material For this reason, the mold and the material are difficult to separate from each other, causing problems such as a decrease in productivity. In particular, as the temperature of the forging die, a temperature in the range of 200 ° C. or more and less than 350 ° C. is advantageously employed.

  And the forging material to which the desired shape obtained by performing such hot forging is applied at a cooling rate of 50 ° C./second or more before the temperature after forging becomes less than 480 ° C., It is cooled to below the temperature of artificial aging and quenched. When quenching is performed after the temperature of the forging material obtained by this forging is lower than 480 ° C., the solute atoms are not sufficiently infiltrated, causing problems such as failure to obtain strength. In addition, when the cooling rate is less than 50 ° C./second, solute atoms are precipitated during cooling, so that the solute atoms are not sufficiently infiltrated into the Al matrix, thereby obtaining strength. It causes problems such as disappearance. The upper limit of the cooling rate is generally set to about 1200 ° C./second from a technical point of view. Further, in order to obtain cooling at a cooling rate of 50 ° C./second or higher, operations such as water cooling and quenching into warm water of 80 ° C. or lower are employed. In forced air cooling by cooling or using a fan or the like, it is difficult to achieve a large cooling rate, and the cooling rate is often less than 50 ° C./second.

  After that, the forging material cooled in this way is heated to a temperature of 160 to 220 ° C. and subjected to an artificial aging treatment for 1 to 30 hours, thereby being excellent in properties such as strength. It becomes a forging material. Here, when such artificial aging treatment conditions are out of regulation, specifically, the precipitation is not sufficient at a treatment temperature of less than 160 ° C. or a treatment time of less than 1 hour, so that sufficient strength cannot be obtained, In addition, when the processing temperature exceeds 220 ° C., coarse precipitates are generated, causing a problem that sufficient strength cannot be obtained. Further, when the processing time exceeds 30 hours, overaging occurs. Insufficient strength cannot be obtained.

  And in the Al alloy forging material obtained by performing such artificial aging treatment, the Vickers hardness in the arbitrary cross section becomes 110HV10 or more, and the average grain size in the surface layer portion is In addition to being 150 μm or less, the maximum particle size of the intermetallic compound is less than 5 μm. In addition, when the Vickers hardness in the arbitrary cross section of this forging material will be less than 110HV10, the strength of a forging material will run short and there exists a problem which tends to cause the damage in use. Here, such hardness is measured in the vicinity of the surface of the forging because the crystal grains are coarsened near the surface and the hardness tends to be low compared to the inside of the forging. It can be said that it is desirable. Further, the average crystal grain size in the surface layer portion of the forged material and the maximum grain size of the intermetallic compound also affect the properties such as strength. In the present invention, the average crystal grain size is 150 μm or less, and the metal By adjusting the maximum particle size of the intermetallic compound to be less than 5 μm, an Al alloy forged material having excellent properties such as strength was advantageously realized.

  Some examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Needless to say. In addition to the following examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements can be made.

  In the following examples, a forged material (test material) 10 obtained by hot forging has a shape and dimensions as shown in FIG. 1, and the evaluation of the characteristics is performed by forging. It was obtained by measuring according to the following test method at the site A shown in FIG.

-Measurement of average crystal grain size of surface layer-
The cross section of the forged material 10 in FIG. 1B is subjected to paper polishing, buffing, and electrolytic polishing, followed by polarization microstructure observation, and an average crystal grain size is calculated by a cutting method. The average crystal grain size in the region up to the depth position was evaluated.

-Measurement of maximum particle size of intermetallic compounds-
The cross section shown in FIG. 1 (b) is adopted as an arbitrary cross section of the forging material 10, and after performing paper polishing and buff polishing, the largest intermetallic compound is photographed with an optical microscope, and image analysis is performed between the metals. The maximum particle size of the compound was measured.

-Measurement of surface layer hardness-
After carrying out paper polishing on the cross section shown in FIG. 1 (b), the Vickers hardness (load: 98 N) is measured according to JIS Z 2244 at a depth position of 6 mm from the forged material surface at the A site. It was measured.

-Evaluation of corrosion resistance-
The forged material (test material) 10 was subjected to a salt spray test based on JIS Z 2371, and the maximum corrosion depth after 720 hours was measured and evaluated as the maximum pitting corrosion depth.

-Example of the present invention-
First, Al alloys having various alloy compositions shown in Table 1 below were melted, and then ingots were formed into various billets having a diameter of 46 mm according to a normal DC casting method. Next, the various billets (ingots) thus obtained were externally cut to have a diameter of 40 mm, and then heated from room temperature at a heating rate of 35 ° C./hour without homogenization. Then, various pre-forging heat treatments as shown in Table 2 below are performed, and then, under various conditions shown in Table 2, forgings 10 having the shapes as shown in FIG. Formed. And immediately after completion | finish of the hot forging, it cooled to room temperature. In the cooling of each forged material 10, the cooling rate was changed by changing the condition of water cooling or hot water cooling. After that, artificial aging treatment was performed on each hot forging material 10 under various processing conditions shown in Table 2 to obtain various hot forging materials 10 of T6 tempering as test materials. It was. The test material No. The forging material according to No. 13 is one that is cooled to 150 ° C. after forging is completed and immediately subjected to artificial aging treatment.

  Next, for the test materials composed of the various forgings 10 thus obtained, the average crystal grain size of the surface layer portion and the maximum particle size of the intermetallic compound are measured, respectively, and the hardness and corrosion resistance of the surface layer portion are evaluated. The results are shown in Table 3 below.

  As is apparent from the results of Table 3, the test material No. Each of the forged materials 10 according to 1 to 15 has an average crystal grain size of the surface layer portion of 150 μm or less, and even if the hardness of the surface layer portion is 110 HV10 or more, and 5 μm It can be seen that the above-described coarse intermetallic compound does not exist and is an Al alloy forged material excellent in corrosion resistance.

-Comparative example-
Al alloys having various alloy compositions shown in the following Table 4 were melted, and various billets were ingoted in the same manner as in the above-described examples of the present invention. Next, the various billets (ingots) thus obtained were externally cut so as to have a diameter of 40 mm, and then heated at a heating rate of 35 ° C./second without performing a homogenization treatment. The test material No. 1 made of T6 tempered forging material 10 was subjected to hot forging and artificial aging treatment under the production conditions shown in Table 5 below. 16-39 were obtained. The cooling rate after forging was changed by changing the water cooling or forced air cooling conditions.

  The test material No. The forged material according to No. 35 is obtained by adopting a condition consisting of preliminarily holding a homogenization treatment at 540 ° C. for 5 hours and then cooling in a manufacturing process for obtaining the forged material. In addition, test material No. The forging material according to No. 36 is obtained by performing a solution treatment consisting of holding at 540 ° C. for 5 hours after forging and cooling, followed by water-cooling quenching, and then artificial aging treatment. Furthermore, the test material No. The forging material according to No. 39 is one that is heated to a target temperature under the condition of a temperature increase rate of 25 ° C./hour as heating for forging.

  The obtained test material No. For 16 to 39, the average crystal grain size of the surface layer part and the maximum grain size of the intermetallic compound were measured in the same manner as in the previous invention example, and the hardness and corrosion resistance of the surface layer part were evaluated. The results are shown in Table 6 below.

  As apparent from the comparison of Table 4 to Table 6, the test material No. 16, 18, 20, 22, 29, 32, and 34, respectively, because the amount of Mg, Si, Cu, or Fe is small, or because the heating temperature or mold temperature before forging is low, Alternatively, it is recognized that the hardness is low due to the slow cooling rate. In addition, test material No. The forged material according to No. 22 has a small amount of Fe, so that the crystal grains of the surface layer are coarsened. The forging material according to No. 17 has a problem that a desired shape cannot be obtained due to a large amount of added Mg and a high deformation resistance of forging. The forged material according to No. 21 has a problem that the corrosion resistance is lowered due to a large amount of Cu.

  In addition, test material No. Forging materials according to 19, 23, 25, 26, 27, 28, and 30 have a large amount of Si, Fe, Ti, Mn, Cr, or Zr, respectively, or heating time before forging. It is recognized that the problem that the maximum particle size of the intermetallic compound is 5.0 μm or more is inherent because it is short. In addition, test material No. The forging material according to No. 24 has a small amount of Ti, and the test material No. Since the forging material according to No. 35 is subjected to reheating for forging after the homogenization treatment, the test material No. Since the forging material according to 36 is subjected to water-cooling quenching after the solution treatment, each of the forging materials has a problem that the crystal grain size in the surface layer portion becomes coarse.

  Furthermore, test material No. Since the forging materials according to 31 and 33 have high heating temperatures and mold temperatures, respectively, the graphite lubrication between the mold and the Al material does not function and adheres, and the material does not come off the mold. It became clear that the intended forging material could not be obtained. In addition, test material No. The forging material according to No. 37 has a low artificial aging temperature and a short time, so that sufficient hardness cannot be obtained. Since the forging material according to No. 38 has a high artificial aging temperature and a long time, the problem arises that the maximum particle size of the intermetallic compound increases and the hardness decreases. The test material No. The forged material according to No. 39 has a low temperature rise rate during heating for forging, and therefore the maximum grain size of the intermetallic compound is increased, and the average crystal grain size in the surface layer portion of the forged material is also increased. Is recognized.

10 Al alloy forging material A Characteristic evaluation part

Claims (3)

  On a mass basis, Mg: 0.6-1.2%, Si: 0.4-1.3%, Cu: 0.03-0.8%, Fe: 0.04-0.5%, and Ti : A forging made of an Al alloy having an alloy composition containing 0.005 to 0.10%, the balance being Al and inevitable impurities, and having a Vickers hardness of 110HV10 or more in an arbitrary cross section, and A high-strength Al alloy forging material excellent in corrosion resistance and workability, characterized in that the average crystal grain size in the surface layer is 150 μm or less and the maximum grain size of the intermetallic compound is less than 5 μm.   The Al alloy is one or two of Mn: 0.01 to 0.9%, Cr: 0.01 to 0.25%, and Zr: 0.01 to 0.25% on a mass basis. The high-strength Al alloy forging material excellent in corrosion resistance and workability according to claim 1, further comprising the above. In the method for producing the high-strength Al alloy forging according to claim 1 or 2,
After the ingot made of the Al alloy obtained by DC casting is heated to a temperature of 490 ° C. or more and less than 550 ° C. at a temperature increase rate of 30 ° C./hour or more, and held at that temperature for 1 to 20 hours, Immediately, hot forging is performed using a forging die heated to 200 to 500 ° C., and before the temperature of the obtained forged material becomes less than 480 ° C., at a cooling rate of 50 ° C./second or more, A method for producing a high-strength Al alloy forging, characterized by cooling to an aging temperature or lower, and then heating to 160 to 220 ° C. and performing an artificial aging treatment for 1 to 30 hours.

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