KR101489745B1 - Three-layer aluminum alloy clad sheet and the method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a three-layer-structured aluminum alloy multilayer clad sheet and a method for manufacturing thereof. More specifically, provided are an aluminum alloy multilayer clad sheet composed of a first layer and a third layer made of a 6000-series aluminum sheet; and a second layer made of a 5000-series aluminum sheet, which is interposed between the first layer and the third layer, and of which a thickness ratio of the first layer, the second layer, to the third layer is 1 : 1.5-2.5 : 0.9-1.1; and a method for manufacturing thereof. The three-layer-structured aluminum alloy multilayer clad plate according to the present invention has an effect of improving mechanical strength such as strength and elongation by bonding aluminum alloy plate materials having different mechanical properties and anisotropy at a specific thickness ratio. In addition, formability is excellent as anisotropy is offset due to different deformation behavior of each alloy layer. Furthermore, a plate material for a vehicle manufacture with the aluminum alloy multilayer clad plate has an advantage of exhibiting lightweightedness of a vehicle body due to aluminum, and excellent corrosion resistance, strength and formability.

Description

[0001] The present invention relates to a three-layered aluminum alloy clad sheet and a method for manufacturing the same,

The present invention relates to an aluminum alloy multi-layered clad sheet and a method of manufacturing the same, and more particularly, to an aluminum alloy multi-layered clad sheet having a three-layered structure of an aluminum 6000 series alloy and a core material of an aluminum 5000 series alloy.

Aluminum alloy is a material having various characteristics such as high strength, corrosion resistance and processability while maintaining a light characteristic of aluminum by adding a certain amount of alloy element to aluminum. Particularly, the aluminum alloy has an excellent non-strength, and its usage as a lightweight automobile is gradually increasing.

Meanwhile, the aluminum alloy is classified according to the kind and amount of the alloy element to be added. Among them, the 5000-series aluminum alloy to which magnesium is added has a large work hardening and excellent moldability as the magnesium content increases, . However, as the magnesium content increases, the corrosion resistance is lowered and stretcher strain marks are generated and applied to the inner plates of automobiles.

On the other hand, the 6000-series aluminum alloy containing magnesium and silicon has an excellent appearance and has a large age hardening effect, which is applied to the outer shell of an automobile, but it has a disadvantage in that it has insufficient formability.

In order to overcome such disadvantages, researches have recently been made to produce an aluminum multi-layer plate made of various alloy layers and to utilize it as a plate excellent in corrosion resistance and moldability.

A clad plate such as an aluminum multi-layer plate is a multi-layer composite plate in which two or more metal plates having different properties are laminated and joined together. For example, a multilayer clad plate having high strength, high corrosion resistance, and processability can be manufactured by joining 6000-type plate materials having excellent corrosion resistance to both surfaces of a 5000-type plate material excellent in strength and workability.

As a method for producing a clad plate composed of various alloy layers, a method of joining different types of metals by adhesives or the like to form a multi-layer structure, rolling or rolling the plate at room temperature or high temperature, and casting and bonding are generally known.

On the other hand, in order to produce products having various shapes by using an aluminum alloy sheet material, a sheet material forming process is performed. The plate material forming process is generally performed by a press forming method in which a plate material is placed on a die having a desired shape and then pressed with a punch.

At this time, the formability depends on the type of alloy, mechanical properties, and the texture of the material developed inside the material. Aluminum alloy sheet has its own microstructure and texture developed through the manufacturing process such as rolling and heat treatment. The plastic deformation behavior necessarily has an anisotropy depending on the direction of the plate material.

Such anisotropy affects the forming process of the plate material. In the case of anisotropic plate material, the deep-drawing process, which is a molding method for producing a seamless hollow container, causes ear generation phenomenon in which the height of the top end of the container is not constant. Such earing must be cut and removed, which is never desirable in terms of productivity.

On the other hand, Korean Patent No. 10-0662727 discloses a manufacturing method of a steel and aluminum clad material and a centrifugal casting machine therefor as a conventional technique related to an aluminum alloy multilayer clad plate. Specifically, the present invention provides a method of manufacturing a steel and aluminum clad material, comprising the steps of: polishing a surface of a steel material to be bonded to have a predetermined roughness; coating aluminum on the polished surface of the steel material by vacuum deposition to have a predetermined thickness; ; Preheating the aluminum coated steel to a predetermined temperature; And cooling the preheated steel material at a predetermined speed while bringing the molten aluminum heated to a predetermined temperature into contact with the aluminum-coated surface of the steel material, followed by cooling the steel material and the aluminum clad material. There is a bar.

However, when the aluminum clad material is manufactured by the above-described method, the process is complicated and the light advantage of aluminum is not included because of the steel.

Accordingly, the inventors of the present invention have been studying the improvement of the mechanical properties and the moldability of the clad plate, and by bonding aluminum alloy sheets having different mechanical properties and anisotropy to each other at a specific thickness ratio, Alloy multi-layer clad plate and completed the present invention.

An object of the present invention is to provide an aluminum alloy multilayer clad plate.

It is another object of the present invention to provide a method of manufacturing an aluminum alloy multi-layer clad sheet.

Furthermore, it is an object of the present invention to provide an aluminum alloy multilayer clad sheet manufactured according to the above-described manufacturing method.

Still further, an object of the present invention is to provide an automotive sheet material including the aluminum alloy multilayer clad sheet.

According to an aspect of the present invention,

A first layer and a third layer made of an aluminum 6000 series plate material; And

And a second layer made of an aluminum 5000 series sheet material disposed between the first layer and the third layer; Wherein the thickness ratio of the first layer, the second layer, and the third layer is 1: 1.5 to 2.5: 0.9 to 1.1.

Further, according to the present invention,

Laminating the aluminum alloy sheet material in a three-layer structure of a first layer which is an aluminum 6000 series plate, a second layer which is an aluminum 5000 series plate and a third layer which is an aluminum 6000 series plate at a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1 Step 1);

A step (step 2) of joining the laminated sheet material of step 1 by cold rolling at a reduction ratio of 30 to 70%;

(Step 3) cold-rolling the rolled multi-layered sheet material in step 2 at a reduction ratio of 30 to 70%;

And a step (step 4) of heat-treating the multi-layered sheet rolled in the step 3 to a temperature of 490 to 520 degrees Celsius.

Further,

There is provided an aluminum alloy multilayer clad sheet produced according to the above manufacturing method.

Go further. According to the present invention,

And an aluminum alloy multi-layer clad plate.

The three-layered aluminum alloy multi-layered clad sheet according to the present invention has an effect of improving mechanical strength such as strength and elongation by bonding aluminum alloy sheets having different mechanical properties and anisotropy to each other at a specific thickness ratio.

In addition, due to the different deformation behavior of each alloy layer, the anisotropy is canceled and the moldability is excellent.

Further, the automobile plate made of the aluminum alloy multi-layered clad sheet has advantages in weight reduction of the automobile body due to aluminum and excellent corrosion resistance, strength and moldability.

1 is a schematic view showing an example of a method for producing an aluminum alloy multilayer clad sheet according to the present invention;
FIG. 2 is a graph showing the temperatures at which heat treatment and aging treatment are carried out in the process for producing an aluminum alloy multi-layered clad sheet according to the present invention;
3 is a photograph of a section of the aluminum alloy multilayer clad sheet produced in Example 2, Comparative Example 3 and Comparative Example 4, observed with an optical microscope;
4 is a schematic view showing a method of measuring a molding height, an amount of ear generation, and a return rate after deep drawing molding;
5 is a photograph showing the shapes of the cups obtained by deep-drawing the aluminum alloy multi-layer clad sheets produced in the control groups 1 and 2 and Example 2 of the present invention.

The present invention

A first layer and a third layer made of an aluminum 6000 series plate material; And

And a second layer made of an aluminum 5000 series sheet material disposed between the first layer and the third layer; Wherein the thickness ratio of the first layer, the second layer, and the third layer is 1: 1.5 to 2.5: 0.9 to 1.1.

Hereinafter, the aluminum alloy multilayer clad sheet according to the present invention will be described in detail.

The present invention provides an aluminum alloy multi-layered clad sheet having a three-layer structure of an aluminum 6000 series alloy and a core material of an aluminum 5000 series alloy.

Aluminum alloys have been increasingly used as automobile lightweight materials due to their excellent non-strength. However, due to the disadvantage that aluminum 5000 alloy is not good in corrosion resistance and aluminum 6000 alloy is inferior in moldability, .

Accordingly, the present invention provides an aluminum alloy multi-layered clad plate made of an aluminum 5000 series alloy as a core material and an aluminum alloy multi-layer clad plate as an aluminum 6000 series alloy, and an aluminum 5000 alloy based on an aluminum 6000 series alloy excellent in corrosion resistance, , All of the advantages of the two alloys can be shown.

In addition, by having the optimum thickness ratio of the core material / the material / core material, it has a high yield strength and elongation, and the anisotropy is canceled by the combination of each material, so that the moldability can be improved, It can be applied as plate for automobile.

Meanwhile, the aluminum alloy multi-layer clad sheet according to the present invention includes the first layer; The second layer and the third layer have a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1.

The second layer preferably has a thickness ratio of 1.5 to 2.5 as compared to the first layer. If the second layer contains a core material of aluminum 5000 series alloy in a ratio of less than 1.5 as compared with the first layer, There is a problem in that the strength of the aluminum alloy multi-layered clad sheet is significantly reduced. When the second layer contains a core material of an aluminum 5000 series alloy in a proportion of more than 2.5 as compared with the first layer, There is a falling problem.

The third layer preferably has a thickness ratio of 0.9 to 1.1 as compared to the first layer. If the third layer has a thickness ratio of less than 0.9 or greater than 1.1 as compared to the first layer, The symmetrical structure of the first layer and the third layer may be broken and the plate material may be bent when rolled, and the formability according to the direction of the top and bottom faces may be changed during molding, have.

At this time, the aluminum alloy multi-layer clad sheet may be subjected to heat treatment after rolling.

The rolling can be performed at a reduction rate of 30 to 70% at room temperature, and if the rolling is performed at a reduction rate of less than 30%, the atomic access between the plates to be bonded is difficult, When the rolling is performed at a reduction ratio exceeding 70%, there is a problem that the rolling material itself can not be rolled due to a too high reduction ratio or the plate material cracks during rolling.

The heat treatment may be performed at a temperature of 490 to 520 ° C. If the heat treatment is performed at a temperature of less than 490 ° C., the strength is not sufficiently high. If the heat treatment is performed at a temperature higher than 520 ° C. The effect of improving the anisotropy is deteriorated.

On the other hand, the aluminum alloy multi-layered clad sheet of the three-layer structure can have a yield strength of not less than 115 MPa and an elongation of not less than 30.2%, and the standard deviation of the elongation measured in the rolling direction, Lt; RTI ID = 0.0 > 0 to 0.54. ≪ / RTI >

The aluminum alloy multi-layered clad sheet according to the present invention exhibits an excellent yield strength and elongation as compared with a conventional plate material such as commercial 5023 aluminum alloy or commercial 6022 aluminum alloy, The anisotropy of each layer of the alloy multi-layered clad sheet is canceled, thereby exhibiting excellent moldability.

Further, according to the present invention,

Laminating the aluminum alloy sheet material in a three-layer structure of a first layer which is an aluminum 6000 series plate, a second layer which is an aluminum 5000 series plate and a third layer which is an aluminum 6000 series plate at a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1 Step 1);

A step (step 2) of joining the laminated sheet material of step 1 by cold rolling at a reduction ratio of 30 to 70%;

(Step 3) cold-rolling the rolled multi-layered sheet material in step 2 at a reduction ratio of 30 to 70%;

And a step (step 4) of heat-treating the multi-layered sheet rolled in the step 3 to a temperature of 490 to 520 degrees Celsius.

An example of a method of manufacturing an aluminum alloy multi-layered clad sheet according to the present invention is shown in the schematic view of FIG. 1. Hereinafter, a method of manufacturing an aluminum alloy multi-layered clad sheet according to the present invention will be described in detail with reference to the drawings.

In the manufacturing method of the present invention, the step 1 is a step of forming a first layer of an aluminum 6000 series plate, a second layer of an aluminum 5000 series plate and a third layer of an aluminum 6000 series plate at a thickness ratio of 1: 1.5 to 2.5: Layer structure of the aluminum alloy sheet.

Conventionally, aluminum 5000 alloy is not good in corrosion resistance, and aluminum 6000 alloy is inferior in moldability.

Accordingly, the present invention provides an aluminum alloy multi-layered clad plate made of an aluminum 5000 series alloy as a core material and an aluminum alloy multi-layer clad plate as an aluminum 6000 series alloy, and an aluminum 5000 alloy based on an aluminum 6000 series alloy excellent in corrosion resistance, , All of the advantages of the two alloys can be shown.

In addition, by having the optimum thickness ratio of the core material / the material / core material, it has a high yield strength and elongation, and the anisotropy is canceled by the combination of each material, so that the moldability can be improved, It can be applied as plate for automobile.

Meanwhile, the aluminum alloy multi-layer clad sheet according to the present invention includes the first layer; The second layer and the third layer have a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1.

The second layer preferably has a thickness ratio of 1.5 to 2.5 as compared to the first layer. If the second layer contains a core material of aluminum 5000 series alloy in a ratio of less than 1.5 as compared with the first layer, There is a problem in that the strength of the aluminum alloy multi-layered clad sheet is significantly reduced. When the second layer contains a core material of an aluminum 5000 series alloy in a proportion of more than 2.5 as compared with the first layer, There is a falling problem.

The third layer preferably has a thickness ratio of 0.9 to 1.1 as compared to the first layer. If the third layer has a thickness ratio of less than 0.9 or greater than 1.1 as compared to the first layer, The symmetrical structure of the first layer and the third layer may be broken and the plate material may be bent when rolled, and the formability according to the direction of the top and bottom faces may be changed during molding, have.

In the manufacturing method of the present invention, the step 2 is a step of cold-rolling and joining the laminated plates of the step 1 at a reduction ratio of 30 to 70%.

In the present invention, rolling is performed at room temperature unlike hot rolling in which a plate is preheated or a roll is preheated, thereby saving energy and reducing the processing cost.

At this time, the rolling of step 2 may be performed at a reduction rate of 30 to 70%. If the rolling is performed at a reduction ratio of less than 30%, the bonding force of the clad sheet material is lowered because the atomic approach between the plates to be bonded is difficult, and the rolling is performed at a reduction ratio exceeding 70% There is a problem in that the sheet itself can not be rolled due to a too high reduction ratio or cracks occur in the sheet during rolling.

In the manufacturing method of the present invention, the step 3 is a step of cold-rolling the rolled multi-layered sheet material in the step 2 at a reduction ratio of 30 to 70%.

In the present invention, a process of rolling the aluminum multi-layered clad sheet of the three-layer structure once subjected to the bonding may be further performed. Through this process, the bonding strength of the aluminum alloy clad sheet may be improved.

At this time, the rolling may be performed at a reduction rate of 30 to 70%.

If the rolling is performed at a reduction ratio of less than 30%, the bonding strength at the bonding interface may not be sufficiently improved. If the rolling is performed at a reduction ratio exceeding 70%, it is too high There is a problem in that the rolling material itself can not be rolled due to the reduction ratio or the plate material cracks during rolling.

In the manufacturing method of the present invention, the step 4 is a step of heat-treating the multi-layered sheet rolled in the step 3 to a temperature of 490 to 520 degrees, and may further include a step of water cooling.

On the other hand, the anisotropy means a phenomenon in which the forming characteristics are changed depending on the direction of the metal plate when bending, stretching, deep drawing or the like is performed using a metal plate. Anisotropy occurs in the aluminum alloy sheet due to development of texture .

However, as in the present invention, by performing the heat treatment on the aluminum alloy multi-layered plate, the aggregate structure is changed, so that the anisotropy is lowered. In addition, the mechanical properties of the material are improved by various strengthening mechanisms such as solidification, precipitation, recrystallization, and grain growth during the heat treatment.

The heat treatment may be performed at a temperature of 490 to 520 degrees.

If the heat treatment is performed at a temperature of less than 490 deg. C, the strength is not sufficiently high. If the heat treatment is performed at a temperature exceeding 520 deg. C, the effect of improving anisotropy is deteriorated.

The heat treatment may be performed for 30 seconds to 3 minutes. If the heat treatment is performed for less than 30 seconds, there is a problem that the strength is not sufficiently high or the effect of improving anisotropy is poor. Minute, there is a problem that the strength may be reduced due to the growth of unnecessary crystal grains.

The method may further include washing the aluminum alloy sheet joined surface before the step of stacking the aluminum alloy sheet material of step 1.

When the surface of the aluminum multi-layer alloy plate to be joined is washed, foreign substances are prevented from entering the inside of the clad plate when laminated and bonded, and the joining between the plate materials is performed more smoothly.

At this time, the aluminum alloy sheet joining surface may be washed using an organic solvent, preferably, acetone.

The method of manufacturing an aluminum alloy multi-layered clad sheet according to the present invention may further include the step of aging the aluminum alloy multi-layered clad sheet produced according to the method.

When the aging treatment is carried out, anisotropy of the aluminum alloy multi-layered clad sheet is improved and excellent mechanical properties can be obtained.

At this time, the aging treatment may be performed at a temperature of 100 to 150 degrees for 30 minutes to 2 hours, and may further include a step of water cooling.

If the aging treatment is carried out below the temperature and time range, the strength is not sufficiently high. If the aging treatment is performed for a time exceeding the temperature and time range, the strength may be lowered There is a problem.

Further,

There is provided an aluminum alloy multilayer clad sheet produced according to the above manufacturing method.

In the case of the aluminum alloy multi-layered clad sheet produced according to the above-described manufacturing method, since the layers are laminated at the optimum thicknesses of the core material, the substrate and the core material, they have high yield strength and elongation, do.

Further, since the rolling is performed at room temperature, there is an effect that the normal cost of the manufacturing is reduced, and the bonding strength of the aluminum alloy clad sheet is improved through additional rolling.

Further, the anisotropy is lowered through the heat treatment step, and an aluminum alloy multilayer clad plate improved in mechanical properties by various strengthening mechanisms such as solidification, precipitation, recrystallization, grain growth and the like can be provided.

Accordingly, the aluminum alloy multi-layered clad sheet of the three-layer structure can have a yield strength of not less than 115 MPa and an elongation of not less than 30.2%. The aluminum alloy multi-layered clad sheet has a standard deviation of elongation measured in the rolling direction, May exhibit low anisotropy of 0 to 0.54.

Go further. According to the present invention,

And an aluminum alloy multi-layer clad plate.

Aluminum alloys have been increasingly used as automobile lightweight materials due to their excellent non-strength. However, due to the disadvantage that aluminum 5000 alloy is not good in corrosion resistance and aluminum 6000 alloy is inferior in moldability, .

Accordingly, the present invention can provide both of the advantages of the two alloys by providing an aluminum alloy multilayer clad plate as a core material of an aluminum 5000 alloy based on an aluminum 6000 alloy excellent in corrosion resistance and having high strength, By having the ratio of thickness of / material / core material, it has high yield strength and elongation, and the anisotropy is canceled by the combination of each material.

Accordingly, the aluminum alloy multi-layer clad sheet of the present invention, which is light in weight, has excellent corrosion resistance and mechanical strength, and has improved moldability, can be applied as an excellent automobile plate material by using an aluminum alloy.

Hereinafter, embodiments of the present invention will be described in more detail. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Control 1

A commercial 5023 aluminum alloy was compared as a control.

Control group 2

A commercial 6022 aluminum alloy was compared as a control.

≪ Example 1 >

Step 1: Using a 5023 aluminum alloy sheet having a thickness of 2 mm as a core and a 6022 aluminum alloy sheet having a thickness of 1 mm as a base, the joint surfaces of the sheet were washed with acetone and then laminated in a three-layer structure of 6022/5023/6022.

Step 2: The aluminum alloy multilayer clad sheet laminated in step 1 was cold-rolled at a reduction ratio of 50%.

Step 3: The aluminum alloy multilayer clad sheet rolled in Step 2 was further cold-rolled at a reduction ratio of 50%.

Step 4: The aluminum alloy multi-layered clad sheet rolled in Step 3 was heat-treated at a temperature of 500 ° C for 1 minute and cooled to prepare an aluminum alloy multi-layered clad sheet.

≪ Example 2 >

An aluminum alloy multilayer clad sheet was prepared in the same manner as in Example 1 except that the aluminum alloy multilayer clad sheet prepared in Example 1 was aged at a temperature of 120 degrees for 1 hour and then cooled.

≪ Comparative Example 1 &

An aluminum alloy multilayer clad sheet was produced in the same manner as in Example 1, except that the thickness of the 6022 aluminum alloy sheet was 2 mm in the step 1 of Example 1 above.

≪ Comparative Example 2 &

An aluminum alloy multilayer clad sheet was prepared in the same manner as in Example 1, except that the thickness of the 6022 aluminum alloy sheet was 0.5 mm in the step 1 of Example 1 above.

≪ Comparative Example 3 &

An aluminum alloy multilayer clad sheet was produced in the same manner as in Example 2 except that the heat treatment temperature in step 3 of Example 2 was 480 degrees.

≪ Comparative Example 4 &

An aluminum alloy multilayer clad sheet was produced in the same manner as in Example 2 except that the heat treatment temperature in step 3 of Example 2 was 530 deg.

Thickness ratio Heat treatment temperature (degree) Whether the aging process Example 1 1: 2: 1 500 × Example 2 1: 2: 1 500 ○ Comparative Example 1 1: 1: 1 500 × Comparative Example 2 1: 4: 1 500 × Comparative Example 3 1: 2: 1 480 ○ Comparative Example 4 1: 2: 1 530 ○

Experimental Example 1 Analysis of Mechanical Strength and Elongation According to Thickness Ratios of Core Material and Substance of Aluminum Alloy Multi-Layer Clad Plate

The tensile strength, yield strength and elongation of the aluminum alloy multilayer clad sheet produced in Example 1 and Comparative Example 1 and Comparative Example 2 were measured, and the results are shown in Table 2.

division Thickness ratio Tensile Strength (MPa) Yield strength (MPa) Elongation (%) Example 1 1: 2: 1 259.1 115.5 30.2 Comparative Example 1 1: 1: 1 228.2 99.5 24.8 Comparative Example 2 1: 4: 1 263.1 112.3 28.2

As shown in Table 2, the yield strength of Example 1 was 115.5 MPa, which is about 16% higher than Comparative Example 1 and about 3% higher than Comparative Example 2. The elongation percentage of Example 1 was 30.2%, which was about 22% higher than that of Comparative Example 1 and about 7% higher than Comparative Example 2. In the case of Comparative Example 1 in which the core material thickness ratio was the smallest at 1: 1: 1, the tensile strength was the lowest at 228.2 MPa. In Comparative Example 2 where the core material thickness ratio was the highest at 1: 4: 1, the elongation was 24.8 %, Respectively.

In the case of Comparative Example 2 in which the thickness ratio of the core material increased, the tensile strength showed a high value but the yield strength and the elongation rate were low. In Comparative Example 1 in which the thickness ratio of the core material decreased, Both elongation rates appeared to be disadvantageous.

As a result, it can be seen that the yield strength and the elongation both have high values in the case of Example 1 in which the ratio of the thicknesses of the substrate, the core material, and the substrate is 1: 2: 1.

<Experimental Example 2> Anisotropic Analysis of Aluminum Alloy Multi-Layer Clad Plate with Heat Treatment Temperature

In order to analyze the anisotropy of the aluminum alloy multi-layer clad sheet produced in Example 2 and Comparative Examples 3 and 4, tensile strength, yield strength and elongation were measured in the rolling direction, the 45 degree direction and the vertical direction, The microstructure photographs shown in Table 3 and observed with an optical microscope are shown in FIG.

division Heat treatment temperature
(Degree) Tensile Strength (MPa) Yield strength (MPa) Elongation (%) Rolling
direction 45 degrees
direction Perpendicular
direction Average Standard Deviation Rolling
direction 45 degrees
direction Perpendicular
direction Average Standard Deviation Rolling
direction 45 degrees
direction Perpendicular
direction Average Standard Deviation Example 2 500 265.1 263.1 266.9 264.6 1.83 124.9 123.1 124.5 123.9 0.94 30.3 30.1 29.1 29.9 0.54 Comparative Example 3 480 250.1 251.2 250.7 250.8 0.52 113.6 113.1 114.6 113.6 0.71 29.6 26.8 29.2 28.1 1.51 Comparative Example 4 530 274.5 267.9 274.5 271.2 3.81 129.5 130.9 129.4 130.2 0.84 27.4 26.5 29.0 27.4 1.18

(Mean = (rolling direction x 2 + 45 degrees direction x 4 + vertical direction x 2) / 8)

As shown in Table 3, in Example 2, not only the best elongation was 29.9% on average, but also the standard deviation of elongation along the direction was the smallest at 0.54. In Comparative Example 3 where the heat treatment temperature was 480 DEG C, the tensile strength and the yield strength decreased sharply to an average of 250.8 MPa and an average of 113.6 MPa. In Comparative Example 4 where the heat treatment temperature was 530 DEG C, The anisotropy increases sharply with the standard deviation of 3.81.

As shown in FIG. 3, in the case of Comparative Example 3 in which the heat treatment temperature was 480 degrees, in the case of Comparative Example 4 in which the grain size of the core was the smallest about 30 to 50 占 퐉 and the heat treatment temperature was 530 占Is about 70 탆 to 130 탆, and the size of the crystal grains increases as the heat treatment temperature is increased. Also, in the case of the substrate, the grain size became larger as the heat treatment temperature was increased. Particularly, it can be confirmed that crystal grains are clearly grown at a high temperature in the core 5023 aluminum alloy sheet.

As a result, when the heat treatment is carried out at a temperature of 500 ° C., the highest elongation is exhibited and the anisotropy of the elongation is the smallest.

EXPERIMENTAL EXAMPLE 3 Moldability Analysis by Deep Drawing

In order to measure the moldability of the aluminum alloy multi-layered clad sheet produced in Example 2, the deep draw test was performed as in the control group 1 and the control group 2, the pass rate was calculated as shown in Fig. 4, And FIG. 5, respectively.

division Molding height (mm) Ear generation (mm) Ear rate (%) Ear location Example 2 27.5 1.4 5.2 Rolling direction, 45 ° direction, vertical direction Control 1 27.5 1.6 5.9 45 degrees Control group 2 27.3 2.1 7.9 Rolling direction, vertical direction

As shown in Fig. 5, the percent enthalpy (%) was calculated by dividing the generated height h by the amount of generated ear Δh after the deep drawing test, and then multiplying by 100.

 As shown in Table 4, the aluminum alloy multi-layered clad sheet produced in Example 2 exhibited a significantly lower value of 5.2% compared to that of Control 1 and Control 2, which were 5.9% and 7.9% in the single materials.

As a result, it can be seen that the anisotropy is canceled by the deformation behavior of each alloy layer in the case of the multi-layer alloy clad sheet than in the case of a single material, and it is understood that the alloy layer has excellent formability.

Claims (16)

A first layer and a third layer made of an aluminum 6000 series plate material; And
And a second layer made of an aluminum 5000 series sheet material disposed between the first layer and the third layer; Wherein the second layer and the third layer have a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1, and an elongation of 30.2% or more.
The method according to claim 1,
And has a yield strength of 115 MPa or more.
delete The method according to claim 1,
An elongation standard deviation in a rolling direction, a 45 degree direction and a vertical direction is 0 to 0.54.
The method according to claim 1,
Wherein the aluminum alloy multi-layered clad sheet is manufactured by rolling and then heat-treating the aluminum alloy multi-layered clad sheet.
6. The method of claim 5,
Wherein the rolling is cold-rolled.
6. The method of claim 5,
Wherein the rolling is performed at a reduction rate of 30 to 70%.
6. The method of claim 5,
Wherein the heat treatment is performed at a temperature of 490 to 520 degrees.
Laminating the aluminum alloy sheet material in a three-layer structure of a first layer which is an aluminum 6000 series plate, a second layer which is an aluminum 5000 series plate and a third layer which is an aluminum 6000 series plate at a thickness ratio of 1: 1.5 to 2.5: 0.9 to 1.1 Step 1);
A step (step 2) of joining the laminated sheet material of step 1 by cold rolling at a reduction ratio of 30 to 70%;
(Step 3) cold-rolling the rolled multi-layered sheet material in step 2 at a reduction ratio of 30 to 70%;
And annealing the multi-layered plate rolled in step 3 to a temperature of 490 to 520 degrees (step 4).
10. The method of claim 9,
Further comprising the step of cleaning the aluminum alloy sheet joining surface before the aluminum alloy sheet stacking step of step 1 is performed.
10. The method of claim 9,
Wherein the heat treatment in step 4 is performed for 30 seconds to 3 minutes.
10. The method of claim 9,
Further comprising the step of aging the aluminum alloy multi-layer clad sheet produced according to the method.
13. The method of claim 12,
Wherein the aging treatment is performed at a temperature of 100 to 150 ° C.
13. The method of claim 12,
Wherein the aging treatment is performed for 30 minutes to 2 hours.
An aluminum alloy multilayer clad plate produced by the manufacturing method of claim 9.
A plate for an automobile comprising the aluminum alloy multilayer clad plate of claim 1.

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