KR20240106699A - High strength aluminum alloy sheet and method of manufacturing the same - Google Patents

Abstract

The present invention provides a high-strength aluminum alloy sheet and a manufacturing method thereof. According to one embodiment of the present invention, the high-strength aluminum alloy sheet has, in weight percent, iron (Fe): more than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, and manganese (Mn): 0%. Greater than 0.15%, Copper (Cu): 0.15% to 0.4%, Magnesium (Mg): 0.8% to 1.2%, Zinc (Zn): Greater than 0% to 0.25%, Chromium (Cr): 0.04% to 0.35%, Titanium (Ti): more than 0% ~ 0.15%, and the balance includes aluminum (Al) and inevitable impurities, yield strength (YS): 300 MPa ~ 420 MPa, tensile strength (TS): 350 MPa ~ 500 MPa, and elongation (EL): satisfies 3% to 10%.

Description

High strength aluminum alloy sheet and method of manufacturing the same}

The technical idea of the present invention relates to aluminum alloy, and more specifically, to a high-strength aluminum alloy sheet and a method of manufacturing the same.

In order to improve the safety and fuel efficiency of automobiles, demand for technologies to make materials lighter and stronger is increasing. In order to respond to these demands, attempts are being made to partially use aluminum alloy materials instead of steel materials such as steel plates for reinforcing materials such as panels and door beams in the automobile body. Furthermore, in order to further reduce the weight of automobile bodies, it is required to expand the application of aluminum alloy materials to automobile structural members such as frames and pillars, which especially contribute to lightweighting.

Aluminum alloy is the most widely used lightweight metal material after steel due to its excellent specific strength and relatively low cost. As such, aluminum alloy is in the spotlight as a lightweight material, but because its mechanical properties are lower than steel materials, there is a need to develop technology to overcome the low strength of aluminum alloy.

Korean Patent Registration No. 10-1950595

The technical problem to be achieved by the technical idea of the present invention is to provide a high-strength aluminum alloy sheet and a manufacturing method thereof.

However, these tasks are illustrative, and the technical idea of the present invention is not limited thereto.

According to one aspect of the present invention, a high-strength aluminum alloy sheet and a manufacturing method thereof are provided.

According to one embodiment of the present invention, the high-strength aluminum alloy sheet has, in weight percent, iron (Fe): more than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, and manganese (Mn): 0%. Greater than 0.15%, Copper (Cu): 0.15% to 0.4%, Magnesium (Mg): 0.8% to 1.2%, Zinc (Zn): Greater than 0% to 0.25%, Chromium (Cr): 0.04% to 0.35%, Titanium (Ti): exceeding 0% ~ 0.15%, and the balance includes aluminum (Al) and inevitable impurities,

Yield strength (YS): 300 MPa ~ 420 MPa, tensile strength (TS): 350 MPa ~ 500 MPa, and elongation (EL): 3% ~ 10% can be satisfied.

According to one embodiment of the present invention, the high-strength aluminum alloy sheet may include dynamic precipitates having a particle size of 10 nm to less than 100 nm.

According to one embodiment of the present invention, the dynamic precipitate may include at least one of Mg ₂ Si, AlFeSi, Al ₁₅ Si ₂ Mn ₄ , and Al ₁₃ Cr ₄ Si ₄ .

According to an embodiment of the present invention, the method for manufacturing the high-strength aluminum alloy sheet is, in weight percent, iron (Fe): more than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, manganese (Mn) : More than 0% ~ 0.15%, Copper (Cu): 0.15% ~ 0.4%, Magnesium (Mg): 0.8% ~ 1.2%, Zinc (Zn): More than 0% ~ 0.25%, Chromium (Cr): 0.04% ~ Manufacturing a cast material with an alloy composition containing 0.35%, titanium (Ti): more than 0% to 0.15%, and the balance containing aluminum (Al) and inevitable impurities; Homogenizing heat treatment of the casting material at 500°C to 600°C; Cryogenically cooling the homogenized heat-treated cast material to -160°C to -195°C; forming a primary rolled material by cryogenically rolling the cryogenically cooled casting material at a rolling end temperature of -160°C to -190°C; And it may include forming a secondary rolled material by warm rolling the cryogenically rolled primary rolled material at a rolling end temperature of 150°C to 250°C.

According to one embodiment of the present invention, the step of forming the primary rolled material may be performed at a reduction rate of 30% to 45%.

According to one embodiment of the present invention, the step of forming the secondary rolled material may be performed at a reduction rate of 40% to 55%.

According to an embodiment of the present invention, the high-strength aluminum alloy sheet manufactured by the method for manufacturing the high-strength aluminum alloy sheet has a yield strength (YS): 300 MPa to 420 MPa and a tensile strength (TS): 350 MPa to 500 MPa. , and elongation (EL): 3% to 10% can be satisfied.

According to one embodiment of the present invention, the high-strength aluminum alloy sheet includes dynamic precipitates having a particle size of 10 nm to less than 100 nm, and the dynamic precipitates are Mg ₂ Si, AlFeSi, Al ₁₅ Si ₂ Mn. It may include at least one of ₄ , and Al ₁₃ Cr ₄ Si ₄ .

According to the technical idea of the present invention, the method of manufacturing a high-strength aluminum alloy sheet is characterized in that it is manufactured by performing cryogenic rolling and warm rolling without performing a heat treatment process such as recrystallization heat treatment and aging heat treatment after conventional rolling. .

By performing the cryogenic rolling, the influence of heat generated during rolling can be minimized, the dynamic recovery of aluminum grains can be suppressed to maximize stored energy, and the nucleation sites can be increased to refine the grains. and the strength can be increased accordingly. Additionally, the nucleation sites of precipitates can be increased by cryogenic rolling.

The warm rolling increases the formation of dynamic precipitates, thereby increasing strength, and compensating for ductility that may be reduced due to suppression of dynamic recovery.

Additionally, since the present invention performs only the rolling process without an additional heat treatment process, productivity can be increased by omitting the heat treatment process.

The effects of the present invention described above have been described as examples, and the scope of the present invention is not limited by these effects.

Figure 1 is a process flow chart showing a method of manufacturing a high-strength aluminum alloy sheet according to an embodiment of the present invention.
Figure 2 is a graph showing the hardness of a high-strength aluminum alloy sheet according to an embodiment of the present invention.
Figure 3 is a photograph showing the microstructure of a high-strength aluminum alloy sheet according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those skilled in the art, and the following examples may be modified into various other forms, and the embodiments of the present invention may be modified. The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided to make the present disclosure more faithful and complete and to fully convey the technical idea of the present invention to those skilled in the art. In this specification, like symbols refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Accordingly, the technical idea of the present invention is not limited by the relative sizes or spacing drawn in the attached drawings.

In order to achieve carbon neutrality and eco-friendly goals, lightweighting of transportation equipment, including automobiles, is required. To meet this, the use of lightweight metals such as aluminum and magnesium has increased, and high strength is necessary.

Conventional 30 kg age hardening type (T6 treatment) Al-Mg-Si alloy generally used Al6061. Changes in the strength and physical properties of the Al6061 alloy are closely related to grain control in the microstructure and generation of MgSi precipitates.

The conventional method of manufacturing aluminum alloy sheets is cold rolling at a temperature of 20°C to 30°C with a reduction ratio of 60% to 90%, and heat treatment at a temperature of 180°C to 220°C for 3 to 7 hours. In the conventional method, because aluminum has high stacking fault energy, dynamic recovery is easy, and because it is limited to grain nucleation sites with low stored energy, there is a limit to grain refinement. Additionally, during mass production, it is difficult to manage before heat treatment after homogenization. The reason is that natural aging may occur due to a delay in the process, and it is difficult to form an optimal supersaturated solution state, thereby limiting the maximization of the aging effect. In addition, a large amount of Mg ₂ Si precipitates are generated, and the heat treatment process time is long for miniaturization, resulting in a decrease in productivity.

Hereinafter, a high-strength aluminum alloy sheet, which is one aspect of the present invention, will be described.

The high-strength aluminum alloy sheet, which is an aspect of the present invention, has, in weight percent, iron (Fe): more than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, manganese (Mn): more than 0% to 0.15%. , Copper (Cu): 0.15% to 0.4%, Magnesium (Mg): 0.8% to 1.2%, Zinc (Zn): >0% to 0.25%, Chromium (Cr): 0.04% to 0.35%, Titanium (Ti) : Exceeding 0% ~ 0.15%, and the balance includes aluminum (Al) and inevitable impurities.

Hereinafter, the role and content of each component included in the high-strength aluminum alloy sheet according to the present invention will be described as follows. At this time, the content of the component elements all refers to weight percent based on the entire aluminum alloy sheet.

Iron (Fe): >0% to 0.7%

Iron (Fe) improves strength by being dissolved in the matrix, and furthermore, it is dispersed as a crystallized product, which has the effect of preventing strength decline, especially at high temperatures. If the iron content exceeds 0.7%, coarse intermetallic compounds are generated during casting, which may cause problems with manufacturability. Therefore, it is desirable to add iron in an amount exceeding 0% to 0.7% of the total weight of the aluminum alloy sheet.

Silicon (Si): 0.4% to 0.8%

Silicon is a major element that affects castability and strength. When the silicon content is less than 0.4%, the effect of improving castability and strength is not significant. If the silicon content exceeds 0.8%, the amount of liquid produced increases, which can dramatically reduce the material strength during heating, makes it difficult to maintain the shape of the sheet, and causes surface defects during plastic processing of aluminum alloy. This can happen. Therefore, it is desirable to add silicon in an amount of 0.4% to 0.8% of the total weight of the aluminum alloy sheet.

Manganese (Mn): Greater than 0% to 0.15%

Manganese forms an intermetallic compound with iron and silicon, acting as a dispersion reinforcement, and is an important addition element that is dissolved in solid solution in the aluminum matrix and improves strength through solid solution strengthening. In addition, manganese is an element that improves elongation and workability by increasing the recrystallization temperature, suppressing the growth of grains, and preventing stress concentration due to strain processing during the hot working process. If the manganese content exceeds 0.15%, coarse intermetallic compounds are likely to be formed, which may reduce processability and corrosion resistance. Therefore, it is preferable to add manganese in an amount exceeding 0% to 0.15% of the total weight of the aluminum alloy sheet.

Copper (Cu): 0.15% to 0.4%

Copper forms an Al ₂ Cu compound with aluminum and forms fine equiaxed crystal grains, thereby increasing the eutectic phase present at the grain boundaries, thereby improving strength. When the copper content is less than 0.15%, the effect of improving strength is not significant. If the copper content exceeds 0.4%, surface defects may occur. Therefore, it is desirable to add copper in an amount of 0.15% to 0.4% of the total weight of the aluminum alloy sheet.

Magnesium (Mg): 0.8% to 1.2%

Magnesium is an element that improves strength by forming a Mg ₂ Si compound with silicon. If the magnesium content is less than 0.8%, the strength improvement effect is not significant. If the magnesium content exceeds 1.2%, the extrudability, surface roughness, and dimensional precision of the aluminum alloy may be greatly reduced, and furthermore, the tendency for oxidation of the molten metal during casting increases. Therefore, it is desirable to add magnesium in an amount of 0.8% to 1.2% of the total weight of the aluminum alloy sheet.

Zinc (Zn): >0% to 0.25%

Zinc improves strength through solid solution strengthening and can further improve the strength of aluminum alloy sheets by implementing a precipitation strengthening effect. If the zinc content exceeds 0.25%, the magnesium-zinc phase may be excessively formed and ductility may be reduced. Therefore, it is preferable to add zinc in an amount exceeding 0% to 0.25% of the total weight of the aluminum alloy sheet.

Chromium (Cr): 0.04% to 0.35%

Chromium has the effect of uniformly distributing the crystalline phase in the aluminum alloy sheet and refining the crystalline phase and crystal grains. In addition, chromium can further improve the strength and ductility of the aluminum alloy sheet by controlling the dynamic recrystallization characteristics during the manufacturing process. If the chromium content is less than 0.04%, the distribution of the crystalline phase is reduced and coarse intermetallic compounds are generated, which may reduce the formability and strength of the aluminum alloy sheet. If the chromium content exceeds 0.35%, it may be difficult to refine the crystalline phase and crystal grains. Therefore, it is desirable to add chromium in an amount of 0.04% to 0.35% of the total weight of the aluminum alloy sheet.

Titanium (Ti): >0% to 0.15%

Titanium is an element that improves castability and, when added to aluminum alloy, contributes to improving strength by refining the ingot structure. If the titanium content exceeds 0.15%, defects such as pores and segregation may occur, or elongation and formability may decrease. Therefore, it is preferable to add titanium in an amount exceeding 0% to 0.15% of the total weight of the aluminum alloy sheet.

The remaining component of the aluminum alloy sheet is aluminum (Al). However, in the normal manufacturing process, unintended impurities may inevitably be introduced from raw materials or the surrounding environment, so this cannot be ruled out. Since these impurities are known to anyone skilled in the ordinary manufacturing process, all of them are not specifically mentioned in this specification.

In addition, the technical idea of the present invention is not limited thereto, and may include, for example, aluminum commercial material A6061.

The high-strength aluminum alloy sheet may satisfy yield strength (YS): 300 MPa to 420 MPa, tensile strength (TS): 350 MPa to 500 MPa, and elongation (EL): 3% to 10%.

The high-strength aluminum alloy sheet may include dynamic precipitates having a particle size of 10 nm to less than 100 nm. The dynamic precipitate may include at least one of Mg ₂ Si, AlFeSi, Al ₁₅ Si ₂ Mn ₄ , and Al ₁₃ Cr ₄ Si ₄ . The dynamic precipitates may be formed within grains or at grain boundaries of the aluminum matrix. Here, precipitates formed as elements diffuse through heat treatment will be referred to as static precipitates, and precipitates formed through rolling will be referred to as dynamic precipitates.

Manufacturing method of high-strength aluminum alloy sheet

Figure 1 is a process flow chart showing a method of manufacturing a high-strength aluminum alloy sheet according to an embodiment of the present invention.

Referring to Figure 1, the manufacturing method of the aluminum alloy sheet is, in weight percent, iron (Fe): more than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, manganese (Mn): more than 0%. ~ 0.15%, Copper (Cu): 0.15% ~ 0.4%, Magnesium (Mg): 0.8% ~ 1.2%, Zinc (Zn): > 0% ~ 0.25%, Chromium (Cr): 0.04% ~ 0.35%, Titanium (Ti): more than 0% to 0.15%, and the balance is a step of manufacturing a cast material with an alloy composition containing aluminum (Al) and inevitable impurities (S10); Homogenizing heat treatment of the casting material at 500°C to 600°C (S20); Cryo-cooling the homogenization heat-treated casting material to -160°C to -195°C (S30); forming a primary rolled material by cryogenically rolling the cryogenically cooled casting material at a rolling end temperature of -160°C to -190°C (S40); and forming a secondary rolled material by warm rolling the cryogenically rolled primary rolled material at a rolling end temperature of 150°C to 250°C (S50).

Casting material manufacturing stage (S10)

In the step of manufacturing a cast material (S10), alloy elements are added to molten aluminum in an amount that satisfies the alloy composition and melted, thereby producing, for example, a semi-finished cast material. In one embodiment, in the step of manufacturing the cast material, the cast material is manufactured through a DC (direct chilled) process using molten aluminum alloy alloyed at 650°C to 750°C.

Homogenization heat treatment step (S20)

In the homogenization heat treatment step (S20), the cast material manufactured as described above is subjected to homogenization heat treatment at 500°C to 600°C. The homogenization heat treatment step may be performed for 10 to 24 hours so that the composition of the entire casting material is uniform. By the homogenization heat treatment step, the cast material is homogenized by solidifying the precipitated phase and crystalline phase such as incomplete Mg ₂ Si, AlFeSi, etc. generated during the casting process. If the homogenization heat treatment temperature is less than 500°C, the precipitates in the matrix are not sufficiently dissolved and it may be difficult to solidify the crystalline phase. When the homogenization heat treatment temperature exceeds 600°C, the cast material is locally re-melted and high-melting point compounds are precipitated, which may lower formability during rolling.

Cryogenic cooling step (S30)

The cast material subjected to the homogenization heat treatment is cryogenically cooled to -160°C to -195°C by spraying liquid nitrogen.

Cryogenic rolling step (S40)

The cryogenically cooled cast material is cryogenically rolled at a rolling end temperature of -160°C to -190°C to form a primary rolled material. The step of forming the primary rolled material may be performed at a reduction rate of 30% to 45%. The cryogenic rolling may be performed in one or more to ten or more rolling passes.

Warm rolling step (S50)

The cryogenically rolled primary rolled material is warm-rolled at a rolling end temperature of 150°C to 250°C to form a secondary rolled material. The step of forming the secondary rolled material may be performed at a reduction rate of 40% to 55%. The warm rolling may be performed in one or more to ten or more rolling passes.

The method for manufacturing a high-strength aluminum alloy sheet according to the technical idea of the present invention is characterized by manufacturing it by performing cryogenic rolling and warm rolling without performing a heat treatment process such as recrystallization heat treatment and aging heat treatment after conventional rolling.

By performing the cryogenic rolling, the influence of heat generated during rolling can be minimized, the dynamic recovery of aluminum grains can be suppressed to maximize stored energy, and the nucleation sites can be increased to refine the grains. and the strength can be increased accordingly. Additionally, the nucleation sites of precipitates can be increased by cryogenic rolling.

The warm rolling increases the formation of dynamic precipitates, thereby increasing strength, and compensating for ductility that may be reduced due to suppression of dynamic recovery.

Additionally, since the present invention performs only the rolling process without an additional heat treatment process, productivity can be increased by omitting the heat treatment process.

Experiment example

Below, preferred experimental examples are presented to aid understanding of the present invention. However, the following experimental examples are only intended to aid understanding of the present invention, and the present invention is not limited by the following experimental examples. Any information not described here can be technically inferred by anyone skilled in the art, so description thereof will be omitted.

Table 1 is a table showing the composition of the high-strength aluminum alloy of the examples of the present invention along with comparative examples. The remainder in Table 1 consists of aluminum (Al) and impurities that are inevitably contained during the manufacturing process. The unit of content of each ingredient is weight%.

division Fe Si Mn Cu Mg Zn Cr Ti Example 1 0.22 0.55 0.02 0.24 0.98 0.01 0.06 0.08 Example 2 0.22 0.55 0.02 0.23 1.01 0.01 0.07 0.08 Example 3 0.22 0.56 0.02 0.24 1.02 0.01 0.07 0.09 Comparative Example 1 0.22 0.55 0.02 0.24 1.01 0.01 0.06 0.07 Comparative example 2 0.21 0.56 0.02 0.22 0.99 0.01 0.05 0.08 Comparative Example 3 0.22 0.56 0.02 0.24 1.01 0.01 0.06 0.07

Referring to Table 1, the comparative examples and examples satisfy the composition range of the present invention.

Table 2 is a table showing the process conditions with the high-strength aluminum alloy of the examples of the present invention along with comparative examples.

division Homogenization
temperature
(℃) room temperature
rolling temperature
(℃) cryogenic
rolling temperature
(℃) Warm
rolling temperature
(℃) heat treatment
temperature
(℃) heat treatment
hour
(city) Example 1 531 - -196 175 - Example 2 530 - -193 178 - Example 3 534 - -190 182 - Comparative Example 1 530 25 - - 200 5 Comparative example 2 535 23 - - 205 5 Comparative Example 3 529 26 - - 197 5

Referring to Table 2, the comparative examples are manufactured by a process consisting of homogenization treatment, room temperature rolling, and heat treatment, while the embodiments of the present invention are manufactured by a process consisting of homogenization treatment, cryogenic rolling, and warm rolling.

Table 3 is a table showing the mechanical properties of the high-strength aluminum alloy of the examples of the present invention, including yield strength, tensile strength, and elongation along with comparative examples.

division yield strength
(MPa) tensile strength
(MPa) elongation
(%) Example 1 401 418 7 Example 2 394 407 6 Example 3 408 420 5 Comparative Example 1 241 290 8 Comparative example 2 246 285 10 Comparative Example 3 250 297 9

Referring to Table 3, Examples 1 to 3 satisfied the target range of the present invention for yield strength (YS), tensile strength (TS), and elongation (EL). Comparative Examples 1 to 3 do not satisfy the target range of the present invention because the yield strength (YS) and tensile strength (TS) are each lower than the lower limit of the target range of the present invention. On the other hand, the elongation was somewhat higher in the comparative examples than in the examples.

Figure 2 is a graph showing the hardness of a high-strength aluminum alloy sheet according to an embodiment of the present invention.

Referring to Figure 2, it can be seen that the comparative example showed the highest hardness when heat treated for 12 hours, while the example showed higher hardness than the highest hardness of the comparative example even though such heat treatment was not performed. Therefore, it can be seen that the strength of the aluminum alloy increases when cryogenic rolling and warm rolling are performed compared to when heat treatment is performed.

Figure 3 is a photograph showing the microstructure of a high-strength aluminum alloy sheet according to an embodiment of the present invention. In Figure 3, (a), (b), and (c) are comparative examples, and (d), (e), and (f) are examples.

Referring to Figures 3 (a) and (d), it can be seen that there is almost no difference in microstructure between the comparative example and the example as an optical microscope picture.

Referring to Figures 3 (b) and (e), transmission electron micrographs show crystal grains stretched by rolling in comparative examples and examples. In the case of the comparative example, precipitates as indicated by arrows appeared, whereas in the examples they did not appear.

Referring to Figures 3 (b) and (e), the comparative example is a scanning electron microscope photograph showing relatively large-sized precipitates, and the precipitates were analyzed as Mg ₂ Si. On the other hand, the example is a transmission electron microscope photograph, and it can be seen that a large amount of nanomillimeter-sized precipitates are formed, as indicated by the arrow.

In this example, it can be seen that by performing cryogenic rolling and warm rolling and not performing subsequent heat treatment, the driving force for generating precipitates increases and a large number of nucleation sites are generated. In addition, it can be seen that the recovery of stretched crystal grains and the generation of dynamic fine nano-precipitates are promoted along with grain refinement behavior. Due to this grain refinement and the formation of dynamic fine nano-precipitates, the strength can be dramatically increased without significantly reducing the elongation. On the other hand, in the case of conventional rolling followed by heat treatment, it can be seen that precipitates having a size of at least several hundred nano millimeters or more are formed.

The technical idea of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible without departing from the technical idea of the present invention. It will be clear to those skilled in the art.

Claims (8)

By weight percent, iron (Fe): greater than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, manganese (Mn): greater than 0% to 0.15%, copper (Cu): 0.15% to 0.4%, Magnesium (Mg): 0.8% to 1.2%, Zinc (Zn): more than 0% to 0.25%, Chromium (Cr): 0.04% to 0.35%, Titanium (Ti): more than 0% to 0.15%, and the balance is aluminum. Contains (Al) and inevitable impurities,
Yield strength (YS): 300 MPa to 420 MPa, tensile strength (TS): 350 MPa to 500 MPa, and elongation (EL): 3% to 10%.
High-strength aluminum alloy sheet. According to claim 1,
The high-strength aluminum alloy sheet contains dynamic precipitates having a particle size of 10 nm to less than 100 nm.
High-strength aluminum alloy sheet. According to claim 1,
The dynamic precipitate includes at least one of Mg ₂ Si, AlFeSi, Al ₁₅ Si ₂ Mn ₄ , and Al ₁₃ Cr ₄ Si ₄ .
High-strength aluminum alloy sheet. By weight percent, iron (Fe): greater than 0% to 0.7%, silicon (Si): 0.4% to 0.8%, manganese (Mn): greater than 0% to 0.15%, copper (Cu): 0.15% to 0.4%, Magnesium (Mg): 0.8% to 1.2%, Zinc (Zn): more than 0% to 0.25%, Chromium (Cr): 0.04% to 0.35%, Titanium (Ti): more than 0% to 0.15%, and the balance is aluminum. Manufacturing a cast material with an alloy composition containing (Al) and inevitable impurities;
Homogenizing heat treatment of the casting material at 500°C to 600°C;
Cryogenically cooling the homogenized heat-treated cast material to -160°C to -195°C;
forming a primary rolled material by cryogenically rolling the cryogenically cooled casting material at a rolling end temperature of -160°C to -190°C; and
Including, forming a secondary rolled material by warm rolling the cryogenically rolled primary rolled material at a rolling end temperature of 150°C to 250°C.
Manufacturing method of high-strength aluminum alloy sheet. According to claim 4,
The step of forming the primary rolled material is performed at a reduction rate of 30% to 45%,
Manufacturing method of aluminum alloy sheet. According to claim 4,
The step of forming the secondary rolled material is performed at a reduction rate of 40% to 55%,
Manufacturing method of high-strength aluminum alloy sheet. According to claim 4,
The high-strength aluminum alloy sheet manufactured by the method for manufacturing the high-strength aluminum alloy sheet,
Yield strength (YS): 300 MPa to 420 MPa, tensile strength (TS): 350 MPa to 500 MPa, and elongation (EL): 3% to 10%.
Manufacturing method of high-strength aluminum alloy sheet. According to claim 7,
The high-strength aluminum alloy sheet,
Contains dynamic precipitates having a particle size of 10 nm to less than 100 nm,
The dynamic precipitate includes at least one of Mg ₂ Si, AlFeSi, Al ₁₅ Si ₂ Mn ₄ , and Al ₁₃ Cr ₄ Si ₄ .
Manufacturing method of high-strength aluminum alloy sheet.