TWI692531B - Aluminum alloy material and method for producing the same - Google Patents

Abstract

The present invention relates to an aluminum alloy material and a method for producing the same. An aluminum slab is firstly provided and subjected to a homogenizated process, thereby obtaining a homogenizated aluminum slab. Next, a cooling process including multiple cooling steps is performed to the homogenizated aluminum slab, so as to adjust a solid-solution amount of a cooled aluminum slab. Then, a hot rolling process and a cold rolling process are performed to the cooled aluminum slab, thereby producing the aluminum alloy material of the present invention. The aluminum alloy material has a suitable amount of pinning particles, thereby enhancing baking strength and pressure resistance of the aluminum alloy material.

Description

Aluminum alloy material and its manufacturing method

The invention relates to an aluminum alloy, in particular to provide an aluminum alloy material with good pressure resistance and baking strength and a manufacturing method thereof.

The market for canned beverages is fiercely competitive, and in order to create new products to increase sales. Some businesses add more carbon dioxide (CO ₂ ) to beverages to increase the content of bubbles in the beverage and increase the taste. However, more carbon dioxide also greatly increases the pressure inside the bottle, which makes the beverage cans have to withstand higher pressures. In addition, in order to reduce the cost of beverage cans, the thickness of the aluminum sheet for making the can body is further thinned to reduce the strength of the can body.

In addition, in order to increase the identification of the beverage can, the bottle body must be painted before filling the beverage. Therefore, the beverage can must be further baked to dry the paint and sterilize the can at the same time. At the same time, the high temperature of the baking process can easily induce the elimination, reorganization and recovery of polygons in the material, and further reduce the strength of the beverage can. Accordingly, in order to prevent thinner bottles from being able to withstand higher pressures in bottles, the quality requirements of beverage cans are becoming stricter.

A conventional method is to control the size of the precipitated particles of the aluminum alloy material to be greater than 1 μm, and adjust the density of the secondary precipitated phase, but the strength after baking cannot be effectively improved, and has a higher lug rate, which cannot Meet the needs of back-end applications. Another conventional method is to add Mg ₂ Si and Al ₆ Mn to the aluminum embryo to reduce the lug ratio of the aluminum alloy material produced, but the strength drop after baking is too large to meet the needs of the application.

Another conventional method is by adjusting the heat treatment parameter settings (for example: increasing the treatment temperature, extending the treatment time or increasing the quenching speed) and/or additionally adding a heat treatment process (for example: adding an intermediate annealing process before the cold rolling process), To adjust the baking strength and pressure resistance of aluminum alloy materials. However, none of these conventional methods have effectively improved the strength of aluminum alloy materials after baking. In addition, the additional intermediate annealing process can easily increase the production cost of aluminum alloy materials, which does not meet the environmental protection requirements of economic efficiency and energy saving.

In view of this, there is an urgent need to provide an aluminum alloy material and a manufacturing method thereof to improve the defects of conventional aluminum alloy materials.

Therefore, one aspect of the present invention is to provide a method for manufacturing an aluminum alloy material, which can adjust the precipitates of the aluminum alloy material obtained by the specific parameters of the homogenization process, the stage cooling and the hot rolling process The quantity and size, and furthermore, during the baking process, can suppress the coarsening of the secondary grains and the dissipation of the difference row, thus improving the baking strength and pressure resistance of the aluminum alloy material.

Another aspect of the present invention is to provide an aluminum alloy material, which is manufactured by the foregoing manufacturing method.

According to one aspect of the present invention, a method for manufacturing an aluminum alloy material is proposed. The aluminum embryo system is provided first and undergoes a homogenization process to obtain a homogenized aluminum embryo. Among them, the material of the aluminum embryo is 3000 series aluminum alloy, and the temperature of the homogenization process is not less than 615°C. Then, the homogenized aluminum embryo is subjected to a cooling process to obtain a cooled aluminum embryo. The cooling process includes a first cooling step, a second cooling step, and a third cooling step, where the first cooling step is to cool the homogenized aluminum embryo to 520°C within 2 hours to 6 hours, and the second cooling step is within 3 hours It is cooled from 520°C to 350°C, and the third cooling step is quenched from 350°C water to room temperature. Next, a hot rolling process is performed on the cooled aluminum blank to obtain a hot rolled aluminum coil, and a cold rolling process is performed on the hot rolled aluminum coil to obtain an aluminum alloy material.

According to an embodiment of the invention, the aforementioned aluminum blank includes greater than 0.2 weight percent copper and greater than 0.2 weight percent zinc.

According to an embodiment of the invention, the temperature of the aforementioned homogenization process is less than the melting point of the aluminum embryo.

According to an embodiment of the invention, the aforementioned homogenization process is performed for at least 12 hours.

According to an embodiment of the invention, the aforementioned hot rolling process includes a hot rough rolling step and a hot finishing rolling step, and the interval between the hot rough rolling step and the hot finishing rolling step is not more than 360 seconds.

According to an embodiment of the present invention, the temperature of the finished coil in the aforementioned hot rolling process is greater than 350°C.

According to an embodiment of the present invention, the cooling rate of the aforementioned hot rolled aluminum coil is not greater than 1°C per minute.

According to an embodiment of the present invention, before the aforementioned cold rolling process, the manufacturing method does not perform an intermediate annealing process.

According to another aspect of the present invention, an aluminum alloy material is proposed, which is manufactured by the aforementioned manufacturing method. This aluminum alloy material contains 30 to 80 pinned particles per cubic micrometer (μm ³ ) of unit volume, and the diameter of each pinned particle is less than 1 μm.

According to an embodiment of the present invention, after baking at 220° C., the yield strength of the aforementioned aluminum alloy material is greater than 260 MPa, and the decrease in yield strength is not greater than 20 MPa.

The aluminum alloy material of the present invention and its manufacturing method are used to control the number and size of the precipitated particles of the aluminum alloy material through the specific parameters of the homogenization process, the staged cooling of the cooling process and the hot rolling process to provide appropriate The pinning force, in the baking process of the back-end application, effectively suppresses the coarsening of secondary grains and the dissipation of the differential rows in the aluminum alloy material, thus improving the baking strength and pressure resistance of the aluminum alloy material.

100‧‧‧Method

110/120/131/133/135/140/150/160‧‧‧Operation

130‧‧‧cooling process

In order to have a more complete understanding of the embodiments of the present invention and its advantages, please refer to the following description and cooperate with the corresponding drawings. It must be emphasized that the various features are not drawn to scale and are for illustration purposes only. The contents of the related drawings are explained as follows: [FIG. 1] is a flowchart showing a method for manufacturing an aluminum alloy material according to an embodiment of the present invention.

The manufacture and use of embodiments of the present invention are discussed in detail below. However, it can be understood that the embodiments provide many applicable inventive concepts that can be implemented in a variety of specific contents. The specific embodiments discussed are for illustration only and are not intended to limit the scope of the invention.

Please refer to FIG. 1, which is a flowchart illustrating a method of manufacturing an aluminum alloy material according to an embodiment of the present invention. The method 100 first provides an aluminum blank, as shown in operation 110. The material of aluminum embryo can be 3000 series aluminum alloy. In some embodiments, the aluminum blank may be 3104 aluminum alloy, 3004 aluminum alloy, other suitable aluminum alloy materials, or any mixture of the foregoing materials. In such embodiments, the aluminum blank may include greater than 0.2 weight percent copper and greater than 0.2 weight percent zinc. Among them, the content of copper and zinc does not exceed the standard content (that is, the standard content of 3000 series aluminum alloy). If the content of copper or zinc is less than 0.2 weight percent, the aluminum alloy material obtained has poor pressure resistance, and cannot meet the application requirements of the back end. If the content of copper or zinc is greater than the standard content, the aluminum alloy material prepared cannot meet the specified specifications, and too much copper or zinc is easy to reduce the corrosion resistance of the aluminum alloy material, so that the aluminum alloy material is easy to be corroded defect.

Then, the aluminum embryo is subjected to a homogenization process, as shown in operation 120. When the homogenization process is performed, the components in the aluminum embryo can be evenly distributed and distributed, which is beneficial to the formation of subsequent precipitates, which can further improve the baking strength and pressure resistance of the aluminum alloy material obtained. Secondly, when casting aluminum embryos, part of the composition tends to form precipitated particles of larger size. During the homogenization process, these precipitated particles can be further refined and reduced. The temperature of the homogenization process is not less than 615℃. In some embodiments, the temperature of the homogenization process is less than the melting of the aluminum embryo point. If the temperature of the homogenization process is less than 615°C, the components in the aluminum embryo cannot be uniformly diffused, which is not conducive to the formation of subsequent precipitates, thus reducing the baking strength and pressure resistance of the aluminum alloy material obtained. In some embodiments, the homogenization process is performed for at least 12 hours.

After operation 120 is performed, a cooling process 130 is performed on the homogenized aluminum embryo produced by the homogenization process. The cooling process 130 includes a multi-stage cooling step (operation 131 to operation 135 shown in FIG. 1) to adjust the number, size and distribution of the precipitates of the aluminum alloy material. First, the first cooling step is performed first to control the size of the precipitate. In some embodiments, the first cooling step is to slowly cool the homogenized aluminum embryo from the temperature of the homogenization process to 520°C. In some embodiments, the first cooling step is to cool the homogenized aluminum embryo to 520°C within 2 hours to 6 hours. If the first cooling step is to cool to less than 520°C, the amount of precipitates will be too much and too dense, which will reduce the baking strength and pressure resistance of the aluminum alloy material produced.

After the first cooling step, the second cooling step is performed to further reduce the temperature of the aluminum blank. In the second cooling step, in order to avoid a large amount of precipitates, the aluminum embryo must be quickly cooled to a set temperature (that is, a temperature lower than the temperature range where precipitates are likely to form) to control the density of the subsequent pinned particles, and The prepared aluminum alloy material can meet the application requirements. In some embodiments, the second aluminum cooling step is within 3 hours, and the aluminum embryo cooled by the first cooling step is cooled to a temperature of 350°C or lower. In other words, in the cooling process 130 of the present invention, the precipitates in the aluminum embryo are mainly precipitated during the first cooling step.

After the second cooling step, the third cooling step is performed. Since the temperature of the aluminum embryo in the second cooling step is already lower than the temperature at which precipitates are easily formed, the cooling rate of the third cooling step is not particularly limited. In some embodiments, in order to shorten the time of the cooling process, the third cooling step can be directly water quenched to room temperature without the aluminum embryo deforming.

After the cooling process 130 is performed, a hot rolling process is performed on the obtained cooled aluminum blank to obtain a hot rolled aluminum coil, as shown in operation 140. In some embodiments, the hot rolling process includes a hot rough rolling step and a hot finish rolling step. Generally speaking, after the hot rough rolling step, due to the limitations of the equipment, the hot rolled aluminum sheet after the hot rough rolling must be transported to the hot finishing mill after a residence time for the subsequent hot finish rolling step (may It is understood that this residence time is the interval time between the hot rough rolling step and the hot finish rolling step). However, the hot rolling process is carried out at a high temperature, so in order to avoid excessive residence time causing the precipitation in the aluminum sheet to precipitate again, the residence time is not more than 360 seconds. Secondly, in order to avoid the temperature of the aluminum alloy sheet produced by the hot rough rolling step decreasing too much, it needs to be reheated, so the residence time is not more than 360 seconds.

In some embodiments, the temperature of the finished coil in the hot rolling process may be greater than 350°C, and the cooling rate of the hot rolled aluminum coil produced in the hot rolling process is not greater than 1°C/min to maintain the required amount of solution .

After operation 140, the hot-rolled aluminum coil is cold-rolled to obtain the aluminum alloy material of the present invention, as shown in operations 150 and 160. In some embodiments, the cold rolling volume of the cold rolling process may be 85% to 90%. In the prepared aluminum alloy material, through the aforementioned homogenization process, cooling process and hot rolling process, the aluminum alloy material has pinned particles (ie, precipitates) with a particle size of less than 1 μm. In some specific examples, the particle density of the pinned particles on the aluminum alloy material is 30 particles/μm ³ to 80 particles/μm ³ .

In the back-end application, after the baked aluminum alloy material is baked at 220°C, the yield strength of the aluminum alloy material is greater than 260 MPa, and the reduction in yield strength is not greater than 20 MPa. Accordingly, the aluminum alloy material prepared by the present invention has good baking strength. Secondly, since the pinned particles are distributed in the aluminum alloy material, the pinned particles can provide the pinning force, and can effectively suppress the movement of grain boundaries and dislocations. Therefore, after baking at high temperature, the average size of the secondary grains of the aluminum alloy material in the lateral direction (that is, perpendicular to the rolling direction) is not greater than 1.5 μm, and the secondary grains are not significantly coarsened. In addition, during baking, the pinned particles can effectively suppress the movement of the differential row, and can reduce the dissipation speed of the differential row, thereby suppressing the degree of reduction of the differential row density (ie, the suppression of the recovery speed). In some specific examples, after baking, the difference in row density of the aluminum alloy material is not less than 10 ¹² cm/cm ³ .

Since the aluminum alloy material of the present invention has an appropriate number of pinned particles, the pressure resistance of the prepared aluminum alloy material is not less than 6.4Kg/cm ² , which can meet the requirements of back-end applications.

In some embodiments, before the cold rolling process, the manufacturing method 100 of the present invention does not require an intermediate annealing process. Therefore, the manufacturing method 100 of the present invention can effectively reduce energy loss and shorten process time.

In an application example, the aluminum alloy material of the present invention has an appropriate amount of precipitates, which can effectively pin the grain boundaries and the movement of the differential row during baking, thereby suppressing secondary grains of the aluminum alloy material after baking Coarseness and difference The speed of dissipation. Therefore, the prepared aluminum alloy material has good baking strength and pressure resistance.

The following examples are used to illustrate the application of the present invention, but it is not intended to limit the present invention. Anyone who is familiar with this art can make various changes and modifications without departing from the spirit and scope of the present invention.

Preparation of aluminum alloy materials

The aluminum alloy materials of Examples 1 to 4 and Comparative Examples 1 to 7 are prepared according to Table 1 below.

Example 1

First, the aluminum alloy raw material that meets the specifications of the 3104 aluminum alloy is subjected to a casting process to obtain the aluminum blank of Example 1. Among them, the contents of copper and zinc are 0.23% by weight. Then, the aluminum embryo is homogenized at a temperature greater than 615°C. After 12 hours, the aluminum blank was cooled, and the cooling process was divided into three stages. In the first cooling step, the aluminum embryo was cooled from the homogenization temperature to 520°C within 3.8 hours. Then, a second cooling step was performed to cool from 520°C to 350°C in 2.14 hours. Next, the aluminum blank was directly cooled to room temperature by water quenching.

After the cooling process, the aluminum blank is hot rolled. Among them, the aluminum alloy sheet produced by the hot rough rolling step undergoes a hot finish rolling step after a residence time of 196 seconds. The temperature of the finished coil of the hot-rolled aluminum coil produced in the hot finish rolling step is 362°C, and the cooling rate is 0.62°C/min. The aluminum coil produced by the hot rolling process is further subjected to a cold rolling process with a cold rolling amount of 85% to 90% to obtain The aluminum alloy material of Example 1 was evaluated by the following evaluation method, and the results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 6

Examples 2 to 4 and Comparative Examples 1 to 6 use the same manufacturing method as the aluminum alloy material of Example 1, except that Examples 2 to 4 and Comparative Examples 1 to 6 Change the content of copper and zinc in the aluminum embryo, as well as the parameter settings of the cooling process, hot rolling process and cold rolling process. The conditions and evaluation results are shown in Table 1, and are not repeated here.

Comparative Example 7

Comparative Example 7 uses the same manufacturing method as the aluminum alloy material of Example 1, except that Comparative Example 7 changes the content of copper and zinc in the aluminum embryo, and after performing the homogenization process, using specific equipment in Within 5 hours, the aluminum embryo was slowly cooled from the homogenization temperature to 480°C to 520°C, and the hot rolling process was directly performed in the same equipment. After the hot rolling process and the cold rolling process, the aluminum alloy material of Comparative Example 7 can be produced. The obtained aluminum alloy raw material was evaluated by the following evaluation method, and the results are shown in Table 1.

Evaluation project 1. Particle density

The particle density of the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 was measured with a transmission electron microscope (TEM).

2. Lug rate

The lug ratio of the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 is measured by a method well known to those of ordinary skill in the technical field to which the present invention pertains, and is performed according to the following criteria Evaluation:

◎: The lug rate is about 1%.

○: The lug rate is about 2%.

×: The lug rate is about 3%.

3. Secondary grain size after baking

First, the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 are placed in an environment of 220° C. to perform a baking process. Then, the size of the secondary grains in the aluminum alloy material is measured with a transmission electron microscope. The secondary grain size refers to the long axis of the equivalent ellipse corresponding to the secondary grain in the lateral direction (that is, perpendicular to the rolling direction).

4. Poor row density after baking

First, the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 are placed in an environment of 220° C. to perform a baking process. Then, a transmission electron microscope is used to measure the differential row density in the aluminum alloy material.

5. Yield strength after baking

First, the yield strength of the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 is measured by methods and instruments well known to those skilled in the art.

Then, the aluminum alloy materials were placed in an environment of 220°C for the baking process. After the baking process is performed, the methods and instruments well-known to those skilled in the art of the present invention are used to measure the baking The yield strength of the aluminum alloy material, and calculate the reduction of the yield strength of the aluminum alloy material before and after baking.

6. Pressure resistance

First, the aluminum alloy materials prepared in Examples 1 to 4 and Comparative Examples 1 to 7 are placed in an environment of 220° C. to perform a baking process. Then, the pressure resistance of the baked aluminum alloy material is measured by methods and instruments well known to those of ordinary skill in the technical field to which the present invention belongs.

Please refer to table 1. In Examples 1 to 4, since the prepared aluminum alloy material has an appropriate number of pinning particles (30 to 80 pinning particles per cubic micrometer of aluminum alloy material), the baking process is performed At this time, these pinning particles can provide sufficient pinning force to limit the movement of secondary grains and differential rows, and can inhibit the coarsening of secondary grains and the degree of differential row dissipation, thereby ensuring the baking of aluminum alloy materials It still has good yield strength, and reduces the drop of yield strength of aluminum alloy materials after baking. Accordingly, the aluminum alloy materials prepared in Examples 1 to 4 have good baking strength. In addition, since the baked aluminum alloy material has good yield strength, it also has good pressure resistance.

In Comparative Example 1, because the time of the first cooling step is too long, the cooling rate is too slow, which leads to coarsening of the pinned particles precipitated, so during baking, the pinning particles inhibit the grain coarsening The effect and the limiting effect of the dissipation of the difference are reduced. According to this, after the baking process, the aluminum alloy material prepared in Comparative Example 1 has a larger strength drop and has a lower yield strength. In Comparative Example 2, since the time of the second cooling step is too long, and The cooling rate of the second cooling step is too slow, and the precipitation amount of the precipitates is greatly increased, thereby further reducing the amount of solid solution in the aluminum alloy material, and thus reducing the strengthening phase therein. Accordingly, after the baking process, the manufactured aluminum alloy material has poor baking strength, and the aluminum alloy material has poor lug ratio, which reduces the finished properties of the aluminum alloy material.

Obviously, the aluminum alloy material of the present invention controls the precipitation amount and size of the pinning particles through multiple stages of cooling, so as to increase the pinning force provided by it, and can improve the baking strength and pressure resistance of the aluminum alloy material produced. To meet the needs of back-end applications.

In Comparative Examples 3 to 5, since the residence time of the hot rolling process is extended (ie Comparative Example 3), the precipitates in the aluminum alloy material are greatly precipitated at this stage, and the solid solution amount of the aluminum alloy material is reduced, Furthermore, the yield strength and pressure resistance after baking are reduced. Secondly, too low the temperature of the finished coil and too fast cooling rate both reduce the amount of solid solution in the aluminum alloy material, and reduce the baking strength and pressure resistance of the aluminum alloy material.

According to this, the method for manufacturing the aluminum alloy material of the present invention can adjust the solid solution amount of the hot rolled aluminum coil produced by an appropriate hot rolling process, and thus effectively reinforce the aluminum alloy material, so the aluminum alloy material of the present invention Can have good baking strength and pressure resistance.

In addition, in Comparative Example 6, the aluminum blank contains too little copper and zinc, which reduces the pressure resistance of the aluminum alloy material produced, so it cannot meet the needs of back-end applications. In Comparative Example 7, since the aluminum alloy material is manufactured with specific equipment, the equipment cost is relatively high. Furthermore, since the aluminum alloy material of Comparative Example 7 is slowly cooled to the set temperature (480°C to 520°C), it is directly hot rolled Therefore, the aluminum alloy material of Comparative Example 7 lacks the aforementioned second cooling step of the present invention. Therefore, the aluminum alloy material of Comparative Example 7 has too many precipitated particles and has a higher strength drop, so it has poorer pressure resistance.

According to the foregoing description, it can be seen that the manufacturing method of the aluminum alloy material of the present invention adjusts the number and size of the pinned particles precipitated in the aluminum alloy material through a homogenization process, a staged cooling and a hot rolling process with specific parameters, and It can provide proper pinning force, thereby improving the baking strength and pressure resistance of aluminum alloy materials.

Although the present invention has been disclosed as above in the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various modifications and changes without departing from the spirit and scope of the present invention. Retouching, therefore, the protection scope of the present invention shall be subject to the scope defined in the appended patent application.

100‧‧‧Method

110/120/131/133/135/140/150/160‧‧‧Operation

130‧‧‧cooling process

Claims (10)

An aluminum alloy material manufacturing method includes: providing an aluminum embryo, wherein the material of the aluminum embryo is 3000 series aluminum alloy; performing a homogenization process on the aluminum alloy blank to obtain a homogenized aluminum embryo, wherein the One of the temperatures of the homogenization process is not less than 615°C; a cooling process is performed on the homogenized aluminum embryo to obtain a cooled aluminum embryo, wherein the cooling process includes: performing a first cooling step, wherein the first cooling step is Cooling the homogenized aluminum blank from the temperature of the homogenization process to 520°C within 2 hours to 6 hours; performing a second cooling step, wherein the second cooling step is cooling from 520°C to 350 within 3 hours ℃; and a third cooling step, wherein the third cooling step is quenched from 350 ℃ water to room temperature; a hot rolling process is performed on the cooled aluminum blank to produce a hot rolled aluminum coil; and the hot The aluminum alloy material can be prepared by rolling an aluminum coil through a cold rolling process. The method for manufacturing an aluminum alloy material as described in item 1 of the patent application scope, wherein the aluminum blank contains greater than 0.2 weight percent copper and greater than 0.2 weight percent zinc. The method for manufacturing an aluminum alloy material as described in item 1 of the patent application range, wherein the temperature of the homogenization process is less than one melting point of the aluminum embryo. The method for manufacturing an aluminum alloy material as described in item 3 of the patent application scope, wherein the homogenization process is performed for at least 12 hours. The method for manufacturing an aluminum alloy material as described in item 1 of the patent scope, wherein the hot rolling process includes a hot rough rolling step and a hot finish rolling step, and the hot rough rolling step is separated from the hot finish rolling step by one The time is not greater than 360 seconds. The method for manufacturing an aluminum alloy material as described in item 1 of the patent application scope, wherein the temperature of one of the finished coils in the hot rolling process is greater than 350°C. The method for manufacturing an aluminum alloy material as described in item 6 of the patent application range, wherein the cooling rate of one of the hot-rolled aluminum coils is not more than 1°C per minute. For the manufacturing method of the aluminum alloy material as described in item 1 of the patent application scope, before the cold rolling process, the manufacturing method does not perform the intermediate annealing process. An aluminum alloy material produced by the manufacturing method as described in any one of claims 1 to 8, wherein the aluminum alloy material contains 30 to 30 micrometers per cubic micrometer (μm ³ ) 80 pinned particles, and the particle size of each pinned particle is less than 1 μm. The aluminum alloy material as described in item 9 of the patent application scope, wherein after a baking process at 220°C, one of the aluminum alloy materials has a yield strength greater than 260 MPa, and the reduction in yield strength is not greater than 20 MPa.

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