KR20170106613A - Fabrication method of aluminum alloy clad sheets and aluminum alloy clad sheets fabricated by the method - Google Patents

Abstract

The present invention relates to a method for manufacturing an aluminum alloy clad plate and an aluminum alloy clad plate manufactured using the same. More specifically, the present invention relates to a method for rolling and joining a plate directly rolled from molten steel at a high temperature. Accordingly, the present invention is able to reduce the manufacturing cost and simplify the process due to no execution of a step of performing wire brushing or heat treatment to perform surface treatment on a surface performed when a conventional aluminum alloy clad plate is manufactured. In addition, the aluminum alloy clad plate manufactured by the manufacturing method above shows low density and high strength and corrosion resistance, and thus has an advantage that when being used in parts of transportation equipment, the fuel efficiency of transportation equipment can be increased and environmental pollution can be reduced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an aluminum alloy clad sheet and an aluminum alloy clad sheet produced using the same,

The present invention relates to a method of manufacturing an aluminum alloy clad plate and an aluminum alloy clad plate manufactured using the same.

Today, aluminum is the second most commonly used metal material after steel industry. Aluminum can be made into various kinds of alloys such as high strength, corrosion resistance and workability according to the kind and amount of added elements such as Cu, Si, Mn, Mg, Zn, and Li. Change.

In other words, aluminum can be made lightweight due to its low density, but it is difficult to use as a material for a structure because of its low tensile strength. On the other hand, aluminum alloy can be strengthened by processing and heat treatment after addition of other elements in spite of low density In recent years, aluminum alloys have attracted attention as lightweight materials having high strength.

Aluminum alloy is a lightweight material with high strength and is used as a material for parts and large structures to lighten various transportation equipments such as automobile, railway car, aircraft, space ship, ship and so on. In addition, And are being studied as measures to cope with various global regulations for environmental pollution and global warming suppression.

Aluminum alloy of 7000 series, which is aluminum alloy with very high strength, which is equivalent to iron among representative aluminum alloys, is an Al-Zn- (Mg, Cu) alloy and can save fuel by lightening parts when used in transportation equipment parts. The effect has a very big advantage. However, the 7000 aluminum alloy has a disadvantage that it is insensitive to stress corrosion cracking, and thus has a disadvantage that it is poor in corrosion resistance, so that it is difficult to use in a corrosive environment. Accordingly, it is necessary to develop a 7000-series aluminum alloy having high strength and excellent corrosion resistance.

Meanwhile, in recent years, studies have been made to fabricate a clad plate in which a plurality of alloys are laminated in multiple layers in order to manufacture an aluminum plate excellent in characteristics, in order to complement the disadvantages of each aluminum alloy.

A clad plate material refers to a multi-layered composite plate in which two or more metal plates having different properties are laminated and joined together, and a multi-layer composite plate having a combination of the characteristics of the respective materials.

Thus, as a method for compensating for the disadvantage of the 7000-series aluminum alloy having poor corrosion resistance, it is possible to manufacture a clad plate material obtained by bonding a 6000-series aluminum alloy excellent in corrosion resistance and surface treatment to the surface of the 7000- When a clad plate material in which a 6000-system aluminum alloy is bonded to the surface of an aluminum alloy is manufactured, an aluminum alloy plate having both the strength of the 7000-system aluminum and the corrosion resistance that is an advantage of the 6000-system aluminum alloy can be manufactured.

As a conventional technique related to an aluminum alloy clad sheet manufacturing method, Korean Patent Registration No. 10-0662727 discloses a method of manufacturing a steel sheet and an aluminum alloy clad sheet. Specifically, the present invention provides a method of manufacturing a steel and aluminum alloy clad sheet material, comprising the steps of: polishing a surface of a steel material to be joined to have a predetermined roughness; Coating an aluminum alloy on the polished surface of the steel material by a vacuum deposition method so as to have a predetermined thickness; Preheating the aluminum alloy coated steel to a predetermined temperature; And cooling the preheated steel material at a predetermined speed so that the aluminum alloy melt heated to a predetermined temperature is brought into contact with the surface of the steel material coated with the aluminum alloy and cooling the preheated steel material. A manufacturing method has been disclosed.

However, when the aluminum alloy clad sheet is manufactured by the above-described method, there is a problem that the process is complicated because it involves a surface treatment and heating for joining the plate.

Korean Patent Laid-Open No. 10-2011-0032440 discloses a method for manufacturing a high strength aluminum alloy clad sheet. Specifically, there is provided a method of manufacturing a brazing material, comprising the steps of: preparing a brazing material comprising a core made of an aluminum alloy thin-cast and an Al-Si based alloy; A material washing step of washing the core material and the brazing material; A brushing step of wire-brushing the outer surface of the core material and the brazing material; A first roll bonding step of laminating the core and the brazing material and roll bonding; A first rolling step of first rolling the roll-bonded core and the brazing material; An annealing step of annealing the primary rolled core and the brazing material; And a second rolling step of secondarily rolling the annealed core and the brazing material to complete a high strength clad plate for brazing.

However, in the case of manufacturing the aluminum alloy clad sheet by the above method, there is a problem in that a process for joining is complicated, such as wire brushing and surface treatment for joining the produced workpiece and core material, and then heating is performed.

Accordingly, the present inventors have developed a method for producing an aluminum alloy clad sheet material in which aluminum alloy clad sheet material is directly or indirectly rolled and rolled in combination in order to simplify the manufacturing process and reduce manufacturing cost. The present invention has been accomplished on the basis of this invention. The present invention has been accomplished on the basis of these findings.

Korean Patent No. 10-0662727 Korean Patent Publication No. 10-2011-0032440

It is an object of the present invention to provide a method for manufacturing an aluminum alloy clad plate and an aluminum alloy clad plate manufactured using the same.

In order to achieve the above object,

(Step 1) of directly rolling a 7000-series aluminum alloy into a 7000-series aluminum alloy core;

Maintaining the manufactured 7000-series aluminum alloy core at a temperature of 380 to 480 캜 (step 2);

(Step 3) of directly rolling a 6000-series aluminum alloy to prepare a 6000-series aluminum alloy article;

Maintaining the manufactured 6000-based aluminum alloy film at a temperature of 380 to 480 캜 (step 4); And

(Step 5) of placing a 6000-series aluminum alloy substrate maintained at a temperature of 380 to 480 캜 on both sides of a 7000-series aluminum alloy core material maintained at a temperature of 380 to 480 캜, followed by rolling and joining A method for producing a clad sheet material is provided.

In addition,

The aluminum alloy clad sheet is manufactured by the above-described method, and includes a 7000-series aluminum alloy core material and a 6000-series aluminum alloy material disposed on both sides of the 7000-series aluminum alloy core material, and has corrosion resistance and high strength.

A method of manufacturing an aluminum alloy clad sheet material according to the present invention is a method of rolling and joining a sheet material rolled directly from a melt at a high temperature state. The surface of the aluminum alloy clad sheet material is processed by wire brushing or heat treatment, The manufacturing cost can be reduced, and the process can be simplified. In addition, the aluminum alloy clad plate manufactured by the above manufacturing method has advantages of low fuel density, high strength and corrosion resistance, and can improve the fuel efficiency of transport equipment and reduce environmental pollution when used as a material for a transportation equipment structure Have.

1 is a device used for producing an aluminum alloy clad sheet of the present invention,
2 is an optical microscope photograph showing a heat-treated section of an aluminum alloy clad sheet manufactured according to an embodiment of the present invention.

The present invention

(Step 1) of directly rolling a 7000-series aluminum alloy into a 7000-series aluminum alloy core;

Maintaining the manufactured 7000-series aluminum alloy core at a temperature of 380 to 480 캜 (step 2);

(Step 3) of directly rolling a 6000-series aluminum alloy to prepare a 6000-series aluminum alloy article;

Maintaining the manufactured 6000-based aluminum alloy film at a temperature of 380 to 480 캜 (step 4); And

(Step 5) of placing a 6000-series aluminum alloy substrate maintained at a temperature of 380 to 480 캜 on both sides of a 7000-series aluminum alloy core material maintained at a temperature of 380 to 480 캜, followed by rolling and joining A method for producing a clad sheet material is provided.

Hereinafter, a method of manufacturing the aluminum alloy clad sheet of the present invention will be described in detail for each step with reference to the drawings.

In the method for producing an aluminum alloy clad sheet according to the present invention, step 1 is a step of directly rolling a 7000-series aluminum alloy into a molten aluminum to produce a 7000-series aluminum alloy core.

7000 series aluminum alloy has a higher strength as the content of added elements such as zinc increases, but it is easy to cause casting defects due to the expansion of the high-coexistence region, and the workability is reduced, The cost of the final material is high. In order to overcome these disadvantages, various researches have been carried out to realize the manufacturing cost of 7000 aluminum alloy in a simple manufacturing process. One of them is a direct rolling method of a molten metal capable of directly producing a plate from a molten metal.

1, the 7000-series aluminum alloy melt 1 is injected between a pair of rotating rolling rolls 2, and then the 7000-series aluminum alloy melt (FIG. 1) 1) is cooled and rolled to form a core. At this time, it is necessary to use a rolling roll having excellent thermal conductivity in order to manufacture the 7000-series aluminum alloy core material by the direct melt rolling method which is directly rolled from the above-mentioned molten metal. In order to solidify the 7000-series aluminum alloy melt for a short period of time passing through the rolling roll 1, the 7000-series aluminum alloy melt must be cooled at a significantly high cooling rate. Therefore, the rolling roll 1 may be made of copper A rolling roll 1 of a copper alloy may be used.

However, the material of the rolling roll 1 is not limited thereto, and a rolling roll 1 of another material capable of rapidly cooling the 7000-series aluminum alloy melt may be used.

In the method of manufacturing the aluminum alloy clad sheet according to the present invention, step 2 is a step of maintaining the manufactured 7000-series aluminum alloy core at a temperature of 380 to 480 캜.

Conventionally, a method of manufacturing a clad plate material made of various alloy layers by a process of wire-brushing and heat-treating an outer surface of a plate material followed by rolling has been disclosed. On the other hand, in the case of the method for producing the aluminum alloy clad sheet of the present invention, the rolling joining is continuously performed after the step of rolling directly from the molten metal. In order to achieve a uniform joining without cracking during the rolling joining, 6000 series aluminum alloy substrate is important. To this end, it is preferable to maintain the 7000-series aluminum alloy core at a temperature of 380 to 480 캜.

If the holding temperature of the 7000-series aluminum alloy core is lower than 380 ° C, the joining strength is lowered or the plate material cracks when the 7000-series aluminum alloy core and the 6000-series aluminum alloy frame are rolled If the holding temperature of the 7000-series aluminum alloy core material exceeds 480 ° C, there is a possibility that the material may melt and break down.

In the method for producing an aluminum alloy clad sheet according to the present invention, Step 3 is a step of directly rolling the 6000-series aluminum alloy to melt the 6000-series aluminum alloy sheet.

The 6000-series aluminum alloy is an aluminum alloy excellent in corrosion resistance, and is laminated on the surface of the 7000-series aluminum alloy having poor corrosion resistance, whereby an aluminum clad plate material having corrosion resistance and high strength can be manufactured.

At this time, the 6000 aluminum alloy substrate can be rolled at a relatively low rolling reduction rate when it is bonded to the 7000 aluminum alloy core material by the direct rolling method. On the other hand, the direct rolling of the molten metal for producing the 6000-series aluminum alloy substrate can be performed in the same manner as in the case of manufacturing the 7000-series aluminum alloy core material.

In the method of manufacturing an aluminum alloy clad sheet according to the present invention, step 4 is a step of maintaining the produced 6000-series aluminum alloy article at a temperature of 380 to 480 캜.

When the 6000-series aluminum alloy substrate is manufactured by the direct rolling method, it is preferable that the 6000-based aluminum alloy substrate is rolled and then maintained at a temperature of 380 to 480 ° C because the 7000- For the same reason that it is maintained at a temperature of 480 캜.

If the temperature at which the 6000 aluminum alloy substrate is directly melted and maintained at a temperature lower than 380 ° C, the temperature of the joining portion is too low during the rolling process with the 7000-series aluminum alloy core material, If the holding temperature of the 6000-series aluminum alloy substrate exceeds 480 ° C, there is a possibility that the material may be melted and fracture may occur.

Meanwhile, the 6000-series aluminum alloy substrate can be manufactured by a conventional method of manufacturing a rolled sheet material, for example, by a method of heat-treating after cold rolling.

In particular, in the case where the 6000-series aluminum alloy substrate is manufactured by a conventional method for manufacturing a rolled plate and is positioned at both sides of the 7000-series aluminum alloy core material at room temperature, the 7000-series aluminum alloy core material is maintained at 430 to 480 캜 Is more preferable. This is for uniformly joining the 6000-series aluminum alloy substrate at room temperature with the 7000-series aluminum alloy without causing cracks during rolling.

If the temperature of the 7000-series aluminum alloy core is lower than 430 ° C. when the 6000-series aluminum alloy substrate is placed on both sides of the 7000-series aluminum alloy core material at room temperature, the temperature of the junction portion is too high If the holding temperature of the 7000-series aluminum alloy substrate exceeds 480 DEG C, there is a possibility that the material may be melted and fracture may occur have.

In the method for producing an aluminum alloy clad sheet according to the present invention, step 5 is a step of forming a 6000-series aluminum alloy substrate maintained at a temperature of 380 to 480 캜 on both sides of a 7000-series aluminum alloy core material maintained at a temperature of 380 to 480 캜 And then rolling and joining.

Preferably, the 6000-based aluminum alloy substrate is placed on both sides of the 7000-based aluminum alloy core material, and the rolling reduction is performed at 15 to 45%.

1, the 7000-series aluminum alloy core material and the 6000-series aluminum alloy ingot are rolled by the rolling joining roll 5 to join them. At this time, the reduction rate is due to the difference in thickness before and after passing through the rolling roll 5, and as the reduction rate is higher, the rolled aluminum alloy clad plate material can be manufactured.

However, when the reduction rate is too high, cracks may be generated on the surface of the aluminum clad sheet material during rolling bonding, and if the reduction rate is too small, a problem may arise that the bonding may not be properly performed at the time of rolling bonding, It is important that the rolling joint is performed.

That is, when the reduction rate is less than 15%, the aluminum alloy clad plate material may not be bonded, and when the reduction rate is more than 45%, the aluminum alloy clad material Cracks may be generated in the plate material.

Conventionally, in order to manufacture a clad sheet by the rolling joining method, a reduction ratio of not less than 40% must be applied, and the surface of the sheet must be subjected to surface treatment such as wire brushing before rolling. In addition, since cracks may occur in the plate during the process of rolling joining at a high reduction ratio, the plate must be subjected to heat treatment and surface treatment before the rolling joining, so that the manufacturing process is complicated and the manufacturing cost is high. On the other hand, in the case of the present invention, the surface treatment process such as wire brushing can be omitted by rolling-bonding the directly melted plate material directly, and rolling bonding can be performed even with a low rolling reduction. In addition, since the plate material directly rolled in the molten metal is heated, the rolling process can be omitted or minimized, thereby simplifying the manufacturing process and reducing the manufacturing cost.

The method of manufacturing an aluminum alloy clad sheet according to the present invention preferably further comprises cold rolling after the rolling joining step. This is for calibrating irregularities or wrinkles that may be formed on the surface of the rolled aluminum alloy clad sheet and further increasing the bonding strength of the joining surface. The thickness and thickness of the aluminum alloy clad sheet produced through the cold rolling process The plate shape can be adjusted more precisely.

In addition,

The aluminum alloy clad sheet is manufactured by the above-described method and has high corrosion resistance and high strength, including a 7000-series aluminum alloy core material and a 6000-series aluminum alloy material disposed on both sides of the 7000-series aluminum alloy core material.

Hereinafter, the aluminum alloy clad sheet of the present invention will be described in detail.

The present invention provides an aluminum alloy clad plate having a three-layer structure of a 7000-series aluminum alloy core and a 6000-series aluminum alloy frame.

Aluminum alloy has been used as lightweight automobile for automobiles due to its excellent non-strength, and the amount of aluminum alloy is gradually increasing. Especially, it is a material attracting attention as a material for lightening 7000 aluminum alloy. However, the 7000-series aluminum alloy has a disadvantage that it is difficult to use in a corrosive environment due to its poor corrosion resistance, which limits its use.

In the present invention, a 6000-series aluminum alloy having excellent corrosion resistance is laminated on the surface of the 7000-series aluminum alloy in order to compensate for the poor corrosion resistance of the 7000-series aluminum alloy.

Further, the aluminum alloy clad plate was manufactured by rolling the 7000-series aluminum alloy sheet directly from the molten metal and then rolling the 6000-series aluminum alloy sheet to obtain a tensile strength of 500 MPa or more and an elongation of 15% or more Is an aluminum alloy clad plate material.

Accordingly, the aluminum alloy clad plate of the present invention having the high strength of the 7000-series aluminum alloy and the corrosion resistance of the 6000-series aluminum alloy, and having a high tensile strength and elongation, And the aluminum alloy clad plate is low in density and can be used as a material for a structure of a transportation device, it has an advantage that the fuel efficiency of the transportation equipment can be increased and the environmental pollution can also be reduced.

Hereinafter, the present invention will be described in detail with reference to the drawings through examples and experimental examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following Examples.

Example 1 Production of Aluminum Alloy Clad Plate (1)

The aluminum alloy clad sheet of the present invention was produced through the following steps.

Step 1: A 7075 aluminum alloy ingot was melted at 740 캜 to prepare a molten metal. Then, the above-prepared molten metal 1 was rolled by a top / bottom rolling roll 1 made of Cu-Cr material having a diameter of 300 mm using the apparatus of Fig. 1 to obtain a 7075 aluminum alloy core material (3 ).

At this time, the upper / lower rolling rolls 1 were preheated to 100 ° C to remove moisture, and the speed of the rolling rolls 1 during the rolling was maintained at 5.652 m / min to 6.123 m / min.

Step 2: The 7075 aluminum alloy core material 3 prepared above was heated so as to be maintained at a temperature of 460 캜.

Step 3: A 6022 aluminum alloy sheet having a thickness of about 1 mm was cold-rolled into a plate having a thickness of 0.2 mm and then heat-treated at 350 DEG C for 1 hour to prepare a 6022 aluminum alloy substrate (4).

Step 4: The prepared 6022 aluminum alloy substrate (4) was maintained at room temperature.

Step 5: The 6022 aluminum alloy substrate at the normal temperature was placed on both sides of 7075 aluminum alloy core material (3) maintained at a temperature of 460 캜, followed by rolling bonding using a rolling roll (5). At this time, the rolling joint was performed at a reduction ratio of 18%.

Step 6: The rolled-bonded aluminum alloy sheet material was cold-rolled to produce an aluminum alloy clad sheet material.

Example 2: Production of an aluminum alloy clad sheet (2)

An aluminum alloy clad sheet material was prepared in the same manner as in Example 1, except that the rolling reduction of Examples 1 to 5 was carried out at a reduction ratio of 36%.

≪ Example 3 > Production of aluminum alloy clad sheet (3)

An aluminum alloy clad sheet material was prepared in the same manner as in Example 1, except that the rolling reduction of Examples 1 to 5 was carried out at a reduction ratio of 43%.

Example 4 Production of Aluminum Alloy Clad Plate (4)

The holding temperature of the 7075 aluminum alloy core material (3) prepared in the above step 2 of Example 1 was changed to 400 ° C, and the 6022 aluminum alloy material (4) was prepared by the direct rolling method of molten steel in the above step 3, The aluminum alloy clad sheet material was produced in the same manner as in Example 1,

At this time, the production of the 6022 aluminum alloy support (4) through direct melt-rolling was carried out through the following process.

6022 aluminum alloy ingot was melted at a temperature of 740 占 폚 to prepare a molten metal. Then, the molten metal 1 prepared above was fed to a top / bottom rolling roll 1 of Cu-Cr material having a diameter of 300 mm using the apparatus shown in Fig. To prepare a 6000-series aluminum alloy substrate (3) having a thickness of about 0.2 mm.

At this time, the upper / lower rolling rolls 1 were preheated to 100 ° C to remove moisture, and the speed of the rolling rolls 1 during the rolling was maintained at 5.652 m / min to 6.123 m / min.

≪ Comparative Example 1 > Production of aluminum alloy clad sheet (5)

An aluminum alloy clad sheet was produced in the same manner as in Example 1, except that the holding temperature of the 7075 aluminum alloy core material (3) prepared in the above step 2 of Example 1 was changed to 400 ° C.

≪ Comparative Example 2 > Production of aluminum alloy clad sheet material (6)

An aluminum alloy clad sheet was produced in the same manner as in Example 1 except that the rolling reduction of Example 1 to 5 was carried out at a reduction ratio of 48%.

≪ Comparative Example 3 > Production of aluminum alloy clad sheet (7)

Except that the holding temperature of the 7075 aluminum alloy core material 3 prepared in the above step 2 of Example 4 was changed to 350 ° C and the holding temperature of the aluminum alloy material 6022 of 6022 was changed to 350 ° C in the above step 4 The aluminum alloy clad sheet material was produced in the same manner as in Example 4.

≪ Comparative Example 4 > Production of aluminum alloy clad sheet (8)

An aluminum alloy clad sheet material was produced in the same manner as in Example 4 except that the rolling reduction of Example 4 to Step 5 was carried out at a reduction ratio of 56%.

The manufacturing conditions used in Examples 1 to 4 and Comparative Examples 1 to 4 were summarized in Table 1 below.

Core material recipe Core holding temperature Recipe Holding temperature Reduction rate Example 1 Direct rolling of molten metal 460 ° C Cold rolling Room temperature 18% Example 2 Direct rolling of molten metal 460 ° C Cold rolling Room temperature 36% Example 3 Direct rolling of molten metal 460 ° C Cold rolling Room temperature 43% Example 4 Direct rolling of molten metal 400 ° C Direct rolling of molten metal 400 ° C 18% Comparative Example 1 Direct rolling of molten metal 400 ° C Cold rolling Room temperature 18% Comparative Example 2 Direct rolling of molten metal 460 ° C Cold rolling Room temperature 48% Comparative Example 3 Direct rolling of molten metal 350 ℃ Direct rolling of molten metal 350 ℃ 18% Comparative Example 4 Direct rolling of molten metal 400 ° C Direct rolling of molten metal 400 ° C 56%

Experimental Example 1 Cracking and Evaluation of Bonding of Aluminum Alloy Clad Plate (1)

 When the 6000-series aluminum alloy substrate of the aluminum alloy clad sheet manufactured by the manufacturing method of the present invention is kept at room temperature, cracks of the aluminum alloy clad sheet due to the holding temperature of the 7000-series aluminum alloy core and the reduction ratio at the rolling- The following experiment was carried out on the aluminum alloy clad sheet produced by Examples 1 to 3 and Comparative Examples 1 and 2. [

The surface cracks of the aluminum alloy clad sheet materials produced in Examples 1 to 3 and Comparative Examples 1 and 2 were examined by an optical microscope, and it was verified whether or not the joints were bonded through a plurality of bonding tests. The results are shown in Table 2 below.

Whether or not Whether cracks have occurred Example 1 Bonded Almost none Example 2 Bonded Almost none Example 3 Bonded Almost none Example 4 Bonded Almost none Comparative Example 1 Not bonded Almost none Comparative Example 2 Bonded Slight occurrence Comparative Example 3 Bonded Severe Comparative Example 4 Bonded Very severe

As shown in Table 2, in Examples 1 to 3 in which the 6022 aluminum alloy substrate was maintained at room temperature and the temperature of the core material of 7075 aluminum alloy was maintained at 460 ° C, the bonding was good and cracks hardly occurred Able to know. On the other hand, in the case of Comparative Example 1 in which the 6022 aluminum alloy substrate was kept at room temperature and the temperature of the 7075 aluminum alloy core was maintained at 400 ° C, it was found that no crack occurred but no bonding occurred.

Further, in Examples 1 to 3, in which rolling reduction was performed under the condition of a rolling reduction of 45% or less, cracks hardly occurred, whereas in Comparative Example 2, which was performed at a reduction ratio of 45% or more, It is seen that it started to occur.

In this case, when the aluminum alloy clad sheet of the present invention is manufactured while keeping the 6022 aluminum alloy substrate at room temperature, the temperature of the 7075 aluminum alloy core is maintained at a temperature of at least 400 ° C and the reduction rate is 45% It can be understood that aluminum alloy clad sheet material having excellent bonding can be produced without causing cracking.

≪ Experimental Example 2 > Cracking and Evaluation of Bonding of Aluminum Alloy Clad Plate (2)

 In the case where the aluminum alloy clad sheet manufactured by the manufacturing method of the present invention is manufactured by directly rolling the 6000-series aluminum alloy substrate, the aluminum alloy clad sheet material The following experiment was carried out on the aluminum alloy clad sheet produced in Example 4, Comparative Examples 3 and 4 to confirm whether or not cracks were generated and bonded.

The surface cracks of the aluminum alloy clad sheet prepared in Example 4 and Comparative Examples 3 and 4 were confirmed by optical microscopy and the bonding was verified through a number of bonding tests, Respectively.

As shown in Table 2, in the case of Comparative Example 3 where the temperature of the 7075 aluminum alloy core material and the 6022 aluminum alloy substrate were kept at 350 캜, the bonding occurred but the cracks were severe, while the 7075 aluminum alloy core material and 6022 It can be seen that Example 4 in which the temperature of the aluminum alloy substrate is maintained at 400 캜 has excellent bonding and cracking properties.

Further, it was found that cracking hardly occurred in Example 4 which was carried out under the condition of the rolling reduction of 45% or less, but in Comparative Example 4 which was carried out at the rolling reduction of 45% or more, have.

In this case, when the 6000-series aluminum alloy substrate is directly rolled by melting, the temperature of the 7000-series aluminum alloy core is maintained at a temperature of at least 350 ° C, and rolled to a rolling reduction of 45% It is possible to produce an aluminum alloy clad sheet material having excellent adhesion even when the aluminum alloy clad sheet material is not produced.

<Experimental Example 3> Evaluation of physical properties of aluminum alloy clad sheet

In order to measure the tensile strength, yield strength and elongation of the aluminum alloy clad sheet produced by the manufacturing method of the present invention, the following experiment was conducted on the aluminum alloy clad sheet produced by Example 4.

The aluminum alloy clad sheet produced in Example 4 was subjected to solution treatment at 480 占 폚 for 1 hour and then aging at 120 占 폚 for 16 hours. The heat-treated aluminum alloy clad sheet was observed through a scanning electron microscope (SEM) to observe its cross section. The results are shown in Fig. 2. In order to measure the tensile strength, 1.5 mm / min. The results are shown in Table 3. &lt; tb &gt; &lt; TABLE &gt;

Tensile Strength (MPa) Yield strength (MPa) Elongation (%) 503 417 15.0%

As shown in FIG. 2, it can be seen that the aluminum alloy clad sheet was uniformly formed with thicknesses of about 0.6 mm and 0.05, respectively, for the 7075 aluminum alloy core and the 6022 aluminum alloy substrate.

On the other hand, as shown in Table 3, the aluminum alloy clad sheet has a tensile strength of 500 MPa or more and an elongation of 15% or less.

As a result, the aluminum alloy clad plate manufactured by the manufacturing method of the present invention is superior in corrosion resistance due to the 6022 aluminum alloy used as a lightweight material and as a substrate, and has excellent strength and formability as a result, It can be expected that when used as transportation material that requires mechanical property, formability and corrosion resistance such as railroad and ship, it can increase fuel efficiency of transportation equipment and reduce environmental pollution.

1: melt
2: Rolling roll
3: 7000 series aluminum alloy core material
4: 6000 series aluminum alloy frame
5: Rolling joint roll

Claims (7)

(Step 1) of directly rolling a 7000-series aluminum alloy into a 7000-series aluminum alloy core;
Maintaining the manufactured 7000-series aluminum alloy core at a temperature of 380 to 480 캜 (step 2);
(Step 3) of directly rolling a 6000-series aluminum alloy to prepare a 6000-series aluminum alloy article;
Maintaining the manufactured 6000-based aluminum alloy film at a temperature of 380 to 480 캜 (step 4); And
(Step 5) of placing a 6000-series aluminum alloy substrate maintained at a temperature of 380 to 480 캜 on both sides of a 7000-series aluminum alloy core material maintained at a temperature of 380 to 480 캜, followed by rolling and joining Clad sheet material.
The aluminum alloy according to claim 1, wherein the manufactured 7000-series aluminum alloy core material is maintained at 430 to 480 캜 and the 6000-series aluminum alloy material is placed at both sides of the 7000-series aluminum alloy core material at room temperature Clad sheet material.
The method of claim 1, wherein the rolling joint of step 5 is performed at a reduction of 15 to 45%.
The method of claim 1, wherein the aluminum alloy clad sheet manufacturing method further comprises a cold rolling step after the rolling joining step.
An aluminum alloy clad sheet comprising a 7000-series aluminum alloy core material and a 6000-series aluminum alloy substrate disposed on both sides of the 7000-series aluminum alloy core material, which is manufactured by the manufacturing method of claim 1, and has corrosion resistance and high strength.
The aluminum alloy clad sheet according to claim 5, wherein the aluminum alloy clad sheet has a tensile strength of 500 MPa or more and an elongation of 15% or more.
The aluminum alloy clad plate according to claim 5, wherein the aluminum alloy clad plate is used as a material for a lightweight structure.

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