JP2012086250A - Aluminum alloy clad plate and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an aluminum alloy clad plate, which can improve deep drawability and stress corrosion cracking resistance while securing adhesiveness of a skin material and core material.SOLUTION: The aluminum alloy clad plate 10 is configured by covering both surfaces of the core material 12 comprising an Al-Mg-based aluminum alloy with the skin material 11 comprising an Al-Mn-based aluminum alloy. The method of manufacturing the aluminum alloy clad plate 10 includes casting the core material 12 by pouring an Al-Mg-based aluminum alloy molten metal 12a that becomes the core material 12 into between a pair of skin materials 11 that faces each other, where the Al-Mn-based aluminum alloy on surfaces 11d is in a solid-liquid coexisting state.

Description

  The present invention relates to a method for producing an aluminum alloy clad material comprising a skin material coated on both surfaces of a core material, and more particularly to a method for producing an aluminum alloy clad material excellent in deep drawability and stress corrosion cracking.

  Conventionally, steel plates are often used for automobiles and the like, but in recent years, aluminum alloys have been used for some parts in order to reduce the weight of vehicles from the viewpoint of environmental resistance. As such an aluminum alloy plate (aluminum alloy), a 5000 series aluminum alloy (Al-Mg series aluminum alloy) as defined by JIS standards is used. Since this Al-Mg-based aluminum alloy contains Mg at a higher concentration than other aluminum alloys, the same strength as steel can be obtained, and the formability is superior to other aluminum alloys. ing.

  However, since the Al—Mg-based aluminum alloy has extremely small local elongation (elongation from tensile strength to fracture), workability such as bending may be inferior to that of a steel plate. Therefore, for example, Al—Mg-based aluminum alloy (JIS standard 5000-based aluminum alloy) containing 3.5 to 10% by mass of Mg is used as a core material, and Mn is contained on both sides of 0.8 to 1.6%. There has been proposed an aluminum alloy laminated plate (aluminum alloy clad material) in which the Al—Mn based aluminum alloy (JIS standard 3000 series aluminum alloy) is used as a skin material and joined by hot rolling (see, for example, Patent Document 1).

  The aluminum alloy clad material obtained in this way has the local elongation of the Al-Mn aluminum alloy as the skin material larger than the local elongation of the Al-Mg aluminum alloy as the core material. Local elongation can be improved.

JP-A-6-228691

  By the way, the Al-Mg-based aluminum alloy improves the deep drawability as the amount of Mg added (content) is increased, but stress corrosion cracking may decrease as a contradiction. Therefore, by applying an aluminum alloy clad material as described in Patent Document 1, an Al—Mn-based aluminum alloy that is resistant to stress corrosion cracking is coated as a skin material. Seems to be.

  However, since the aluminum alloy clad material described in Patent Document 1 is a clad material in which the skin material and the core material are joined by hot rolling, due to the difference in strength and alloy components between the skin material and the core material, It may be difficult to ensure the adhesion of the core material.

  The present invention has been made in view of such problems, and its object is to improve the deep drawability and stress corrosion cracking resistance while ensuring the adhesion between the skin material and the core material. Another object of the present invention is to provide a method for producing an aluminum alloy clad material.

  As a result of intensive studies to solve the above problems, the inventors have ensured that the joint surface between the two is in a molten state (at least in order to secure the adhesion between the skin material and the core material that can withstand the formability by deep drawing. It was considered preferable to join in a semi-molten state. From this point of view, for example, (1) A method of preparing a core material made of an Al—Mg-based aluminum alloy and casting the core material with a molten Ml—Mn-based alloy serving as a skin material, (2 ) A method of casting these molten metals sequentially between rolls and casting them is also conceivable.

  However, generally, the melting point (about 568 to 652 ° C.) of the Al—Mg-based aluminum alloy as the core material is lower than the melting point (about 629 ° C. to 657 ° C.) of the Al—Mn-based aluminum alloy as the skin material. In the method shown in (1), when the core material is brought into contact with the melted skin material, the core material is melted and cannot be maintained in a desired shape, and the components of the skin material and the core material are It will be mixed. In the case of the method shown in (2), the same result as in (1) is obtained, and furthermore, it is difficult to coat the skin material under the same heating conditions on both surfaces of the core material. As a result, a new finding was obtained that the obtained clad material could not sufficiently exhibit the effect of improving deep drawability and stress corrosion cracking resistance.

  The present invention is based on such knowledge, and the method for producing an aluminum alloy clad material according to the present invention includes a skin made of an Al-Mn aluminum alloy on both surfaces of a core material made of an Al-Mg aluminum alloy. A method for producing an aluminum alloy clad material coated with a material, wherein in the production method, between the pair of skin materials in which at least the facing Al-Mn-based aluminum alloy is in a solid-liquid coexistence state, the core material and The core material is cast by pouring a molten Al-Mg aluminum alloy.

  According to the present invention, the surface of the skin material serving as the joint surface of the core material is in a solid-liquid coexistence state, and the core material is obtained by pouring a molten Al-Mg-based aluminum alloy serving as the core material into the surface in this state. Since casting is performed, a diffusion layer having high adhesion in which the Mg component of the core material diffuses into the material of the skin material is formed between both surfaces of the core material and the skin material. At the same time, since the molten Al-Mg aluminum alloy is brought into contact with the surface of the skin material, the diffusion layers on both sides are in a substantially homogeneous state. Furthermore, since the melting point of the skin material is higher than the melting point of the core material, even if a molten metal as the core material is poured, the skin material is not deformed and a clad material having a good bonded state is obtained. be able to.

  In addition, Al—Mg-based aluminum alloys easily form oxides due to the addition of Mg. However, since the molten Al—Mg-based aluminum alloy is directly brought into contact with the surface of the skin material, oxides are present at the interface. An aluminum alloy clad material that is difficult to be formed and has high bondability can be obtained. In this way, the rolled material obtained by rolling the obtained aluminum-based alloy clad material (ingot material) is superior in deep drawability to conventional ones and also has improved stress corrosion cracking resistance.

  Here, the Al—Mg-based aluminum alloy referred to in the present invention means a material corresponding to a component of a 5000-based aluminum alloy defined in JIS standards, and the Al—Mn-based aluminum alloy referred to in the present invention is It means a material corresponding to the component of 3000 series aluminum alloy specified in JIS standard.

  In addition, the solid-liquid coexisting skin material may be a skin material that has been heated to a semi-molten state in which the solid phase and the liquid phase coexist, and after the metal material is dissolved, the solid phase and the liquid phase May be a semi-solidified skin material, and at least the temperature condition of the surface of the skin material should ensure a temperature between the solidus and liquidus.

  However, as a more preferred embodiment, a pair of skin materials whose opposite surfaces are in the solid-liquid coexistence state are cast by flowing a molten Al-Mn aluminum alloy serving as the skin material at opposing positions.

  In the case where the skin material is made to be in a semi-molten state by heating, the surface of the skin material is heated to a solid-liquid coexistence state, and then the molten metal is poured by arranging them facing each other, which is a complicated operation. However, according to this aspect, the aluminum alloy clad material can be manufactured more easily and continuously.

  Moreover, as a more preferable aspect, Mg contained in the Al—Mg-based aluminum alloy is an aluminum alloy in the range of 4.5 to 5.5% by mass, and contained in the Al—Mn-based aluminum alloy. An aluminum alloy having Mn in the range of 1.0 to 3.0% by mass is used.

  According to this aspect, an aluminum alloy clad material excellent in deep drawability and stress corrosion cracking resistance can be suitably produced. That is, when the content of Mg contained in the Al-Mg-based aluminum alloy constituting the core material is less than 4.5% by mass, the workability of deep drawing decreases and exceeds 5.5% by mass. In such a case, the fluidity of the molten metal may be reduced. Further, when the Mn contained in the Al—Mn-based aluminum alloy constituting the skin material is less than 1.0% by mass, the elongation decreases and becomes brittle, and the Mn exceeds 3.0% by mass. If so, the crystal grains become coarse and the moldability may be reduced.

  According to the present invention, it is possible to improve the deep drawability and stress corrosion cracking resistance of the aluminum alloy clad material while ensuring the adhesion between the skin material and the core material.

The figure for demonstrating the process of manufacturing the skin material of the aluminum alloy clad material which concerns on this embodiment. The figure for demonstrating the process of pouring the molten metal of the core material of the aluminum alloy clad material which concerns on this embodiment. The figure for demonstrating the manufacturing process of the aluminum alloy clad material which concerns on this embodiment. It is the photograph which showed the joining state of the aluminum alloy cladding material which concerns on Example 1 and Comparative Example 1, (a) is the photograph figure which showed the joining state of the aluminum alloy cladding material which concerns on Example 1, b) is a photographic view showing the bonding state of the aluminum alloy clad material according to Comparative Example 1. The enlarged photograph figure of the junction part of the aluminum alloy clad material which concerns on Example 1. FIG. The figure which showed the result of the deep drawing test of Example 1 and Comparative Examples 2 and 3. The figure which showed the result of the stress corrosion cracking of Example 1 and Comparative Examples 2 and 3.

  Below, with reference to drawings, it explains based on the embodiment which can manufacture the aluminum alloy clad material concerning the present invention suitably.

  FIG. 1 is a diagram for explaining a process of manufacturing a skin material of an aluminum alloy clad material according to the present embodiment, and FIG. 2 is a process of pouring a molten metal of the core material of the aluminum alloy clad material according to the present embodiment. FIG. 3 is a diagram for explaining a manufacturing process of the aluminum alloy clad material according to the present embodiment.

  As shown in FIGS. 1-3, it is the manufacturing apparatus 30 which manufactures an aluminum alloy clad material, and is an apparatus for performing what is called a composite ingot casting. The manufacturing apparatus 30 includes a pair of first molten metal nozzles 31 and 31 that supply a molten metal 11a of an Al—Mn-based aluminum alloy, and a second molten metal nozzle 32 that supplies a molten metal 12a of an Al—Mg-based aluminum alloy. ing. Above these nozzles 31, 32 are a chamber (not shown) for storing the molten metal, a heating unit (not shown) for heating the molten metal in the chamber and controlling the temperature of the molten metal, and the nozzle 31. , 32 is provided with a throttle (not shown) for adjusting the flow rate of the molten metal supplied to.

  Separation plates 34 and 34 are provided between the first molten metal nozzles 31 and 31 and the second molten metal nozzle 32, and the molten metal 11a of the Al-Mn based aluminum alloy and the Al-Mg based aluminum alloy are separated. The molten metal 12a is not mixed. Further, the separation plate 34 is provided with a temperature adjusting device (not shown) for adjusting the temperature of the molten metal 11a, 12a.

  Further, water cooling jackets 36 and 36 are provided outside the first molten metal nozzles 31 and 31, and the cooling water W is supplied to the molten metal 11 a of the Al—Mn-based aluminum alloy supplied from the first molten metal nozzle 31. By supplying, the molten metal 11a is cooled.

  The wall surface of the water cooling jacket 36 and the wall surface of the separation plate 34 act as a mold at the time of casting, and it is possible to cast the skin material to a predetermined thickness from the molten metal 11a of the Al—Mn based aluminum alloy.

  A cylinder 39 that can be moved up and down is provided at the lower part of the manufacturing apparatus 30, and a block 37 that receives the Al—Mn-based aluminum alloy and the Al—Mg-based aluminum alloy at the upper part, and the block 37 And a plate 38 fixed to the cylinder 39.

  By using such an apparatus 30, the aluminum alloy clad material according to the present embodiment is manufactured. Specifically, as shown in FIG. 1, first, the cylinder 39 is moved to the upper limit, and a pair of first molten metal nozzles 31, a space formed in the water cooling jacket 36, the separation plate 34, and the block 37, The molten metal 11a of Al-Mn type aluminum alloy is supplied from 31.

  As a result, the molten metal 11a is cooled in a portion adjacent to the block 37, and an Al—Mn based aluminum alloy solid phase portion 11c is formed. Between the molten metal 11a and the solid phase portion 11c, Al—Mn is formed. The solid-liquid coexistence part 11b in which the solid phase and the liquid phase of the system aluminum alloy coexist is formed. In addition, the temperature of this solid-liquid coexistence part 11b is the temperature between the temperature of the solidus line of an Al-Mn type aluminum alloy, and the temperature of a liquidus line.

  Next, as shown in FIG. 2, a solid-liquid coexistence portion 11 b is formed on the surface 11 d serving as the skin material below the separation plate 34 (so that the surface 11 d is in a solid-liquid coexistence state). The cylinder 39 is lowered and the molten metal 11a is suspended.

  At this time, the cooling water W is allowed to flow from the water cooling jacket 36 to cool the molten metal 11a. In this way, by flowing the Al—Mn-based aluminum alloy melt 11a serving as the skin material at the opposed positions, a pair of skin materials in which the opposed surfaces 11d are in a solid-liquid coexistence state can be cast. Since the surface 11d is in a semi-solid state, it becomes a self-supporting surface for maintaining the shape of the skin material.

  In such a state, the molten metal 12a of the Al—Mg-based aluminum alloy is supplied from the second molten metal nozzle 32. As a result, the molten metal 12a is cooled in a portion adjacent to the block 37, and an Al—Mg-based aluminum alloy solid phase portion 12c is formed. Between the molten metal 12a and the solid phase portion 12c, Al—Mg is formed. The solid-liquid coexistence part 12b in which the solid phase and the liquid phase of the system aluminum alloy coexist is formed. In addition, the temperature of this solid-liquid coexistence part 12b is a temperature between the temperature of the solidus line of Al-Mg type aluminum alloy, and the temperature of a liquidus line.

  In this way, as shown in FIG. 2, at least the Al—Mn-based aluminum which is the core material between the pair of skin materials 11 in which the Al—Mn-based aluminum alloy on the surfaces 11d and 11d facing each other is in a solid-liquid coexistence state. The core material 12 is cast by pouring a molten aluminum alloy.

  Further, as shown in FIG. 3, by lowering the cylinder 39, an aluminum alloy clad material in which the skin material 11 made of an Al-Mn aluminum alloy is coated on both surfaces of the core material 12 made of an Al-Mg aluminum alloy. (Ingot material) 10 is continuously cast.

  In this way, the surface 11d of the skin material 11 serving as the joint surface of the core material 12 is in a solid-liquid coexistence state, and the Al—Mg-based aluminum alloy melt 12a serving as the core material 12 is poured into the surface 11d in this state. Since the core material 12 is cast by this, a diffusion layer 12d with high adhesion in which components such as Mg of the core material diffuse into the surface layer of the skin material 11 is provided between the core material 12 and the skin materials 11 and 11. The diffusion layers 12d on both sides are in a substantially homogeneous state.

  In addition, although Al—Mg-based aluminum alloy is easy to form an oxide by adding Mg, the Al—Mg-based aluminum alloy molten metal 12a is directly brought into contact with the surface 11d of the skin material 11, so that the interface is formed at the interface. Can form an aluminum alloy clad material 10 that is difficult to form oxides and has high bondability.

  In the embodiment, the Al—Mn-based aluminum alloy is a material corresponding to a component of the 3000-based aluminum alloy specified in JIS standards, and the Mn contained in the Al—Mn-based aluminum alloy is 1.0. It is preferable to use an aluminum alloy in the range of ˜3.0% by mass.

  On the other hand, the Al—Mg-based aluminum alloy is a material corresponding to the component of the 5000-based aluminum alloy specified in JIS standards, and Mg contained in the Al—Mg-based aluminum alloy is 4.5 to 5.5 mass. It is preferable to use those within the range of%. By using an alloy material in such a range, the aluminum alloy clad material 10 excellent in deep drawability and stress corrosion cracking resistance can be suitably manufactured.

  The thickness of the skin material of the aluminum alloy clad material (ingot material) 10 is preferably in the range of 5 to 10% of the total thickness. By setting it as such a range, the effect of the stress corrosion cracking resistance by a skin material can be improved, and the deep drawability effect by a core material can be improved. Such an aluminum alloy clad material can be manufactured by adjusting the position (interval) between the separation plate 34 and the water cooling jacket 36.

  Further, an aluminum alloy clad material (rolled material) in which a cast aluminum alloy clad material (ingot material) 10 is rolled to cover both surfaces of a core material made of a 5000 series aluminum alloy and a skin material made of a 3000 series aluminum alloy. ) Can be obtained. This rolled material is excellent in deep drawability and stress corrosion cracking resistance as compared with the conventional material.

  Hereinafter, the present invention will be described by way of examples. The following examples are carried out in accordance with the present embodiment shown above, but do not limit the present invention.

Example 1
An aluminum alloy clad material was manufactured using the apparatus shown in FIG. Specifically, a molten metal containing 5.5% by mass of Mg as a molten Al-Mg aluminum alloy (JIS standard: equivalent to 5023 aluminum alloy) and 1.0 Mn as a molten Al-Mn aluminum alloy. A molten metal containing mass% (JIS standard: equivalent to 3003 aluminum alloy) was prepared.

  Next, a molten metal of Al—Mn based aluminum alloy at a temperature of 620 ° C. was poured to lower the cylinder so that the surface below the separation plate was in a solid-liquid coexistence state. In this state, a molten Al—Mg-based aluminum alloy at a temperature of 580 ° C. is poured between a pair of skin materials in which the Al—Mn-based aluminum alloy on the opposite surface is in a solid-liquid coexistence state, and the skin material is cored. These were cast while being joined to the material. The surface temperature of the Al—Mn-based aluminum alloy is a temperature between the liquidus temperature and the solidus temperature, and here, the temperature of the molten metal of the Al—Mn-based aluminum alloy so as to be 610 ° C. Adjusted by managing.

  The thickness of the skin material was 10% of the total thickness. The cast aluminum alloy clad material (ingot material) thus obtained is hot-rolled to 1 mm and cold-rolled, so that Al—Mn-based aluminum is formed on both surfaces of the core material made of an Al—Mg-based aluminum alloy. An aluminum alloy clad material (rolled material) coated with an alloy skin material was obtained.

(Comparative Example 1)
In the same manner as in Example 1, an aluminum alloy clad material was produced. The difference from the example is that the surface temperature of the molten Al-Mn-based aluminum alloy is 580 ° C. by controlling the temperature of the Al—Mn-based aluminum alloy. The ingot material was manufactured by pouring a molten Al-Mg aluminum alloy under the same conditions.

(Comparative Examples 2 and 3)
In Comparative Example 2, an aluminum alloy material containing 5.5% by mass of Mg corresponding to the core material of Example 1 was manufactured. In Comparative Example 3, an aluminum alloy material containing 4.5% by mass of Mg corresponding to the core material of Example 1 was manufactured. In addition, these aluminum alloy materials are the same thickness as the aluminum alloy clad material of Example 1.

<Microscopic observation of joint part>
The joint portion between the skin material and the core material of Example 1 and Comparative Example 1 was observed with a microscope. The results are shown in FIG. 4 and FIG. FIG. 4A is a photographic view showing the bonding state of the aluminum alloy cladding material according to Example 1, and FIG. 4B shows the bonding state of the aluminum alloy cladding material according to Comparative Example 1. FIG. FIG. 5 is an enlarged photograph of the joined portion of the aluminum alloy clad material according to the first embodiment.

<Deep drawing test>
Using an Erichsen testing machine, the deep drawing tests of Example 1 and Comparative Examples 2 and 3 were performed. Specifically, a deep drawing test was performed on each material under the conditions of drawing speed: 20 mm / min, wrinkle holding force: 30 kN, mold: blank φ120 mm, drawing mold t = 1.2, punch diameter 50 mm, The drawing height (drawing depth) at which deep drawing can be performed (until breakage) was measured. The result is shown in FIG.

<Stress corrosion cracking test>
The stress corrosion cracking test of Example 1 and Comparative Examples 2 and 3 was performed. Specifically, a bending load was repeatedly applied using a three-point bending jig in accordance with ASTME 39-99 under predetermined salt spray conditions. The result is shown in FIG.

[Results and discussion]
As shown in FIGS. 4A and 4B, in the aluminum alloy clad material of Example 1, the Al—Mn aluminum alloy that is the skin material and the Al—Mg aluminum alloy that is the core material are well bonded. However, the aluminum alloy clad material of Comparative Example 1 had an unjoined portion.

  Further, as shown in FIG. 5, in the case of Example 1, the Mg component of the core material is the skin material between the Al—Mn aluminum alloy that is the skin material and the Al—Mg aluminum alloy that is the core material. A diffusion layer was formed on the surface layer of the film. This elemental diffusion of Mg was confirmed by EPMA.

  As described above, the aluminum alloy clad material of Example 1 was satisfactorily bonded because Al—Mg serving as a core material was placed between a pair of skin materials in which an Al—Mn-based aluminum alloy is in a solid-liquid coexistence state. This is probably because a diffusion layer was formed by pouring a molten aluminum alloy.

  Further, as shown in FIG. 6, the aluminum alloy clad material of Example 1 has a higher deep drawing height than the aluminum alloy materials of Comparative Examples 2 and 3, and is about 8% deeper than that of Comparative Example 2. It can be said that the drawing height is high and the deep drawing property is good. The reason for this is considered to be that uniform elongation (elongation to tensile strength) was improved by using an Al—Mn aluminum alloy for the skin material.

  Furthermore, as shown in FIG. 7, the aluminum alloy clad material of Example 1 does not generate stress corrosion cracking even when applied repeatedly 100 times, and Comparative Examples 2 and 3 are less than 30 times. Corrosion cracking occurred. In the case of Example 1, this reason is considered to be because the stress corrosion cracking was improved by using an Al—Mn aluminum alloy for the skin material.

  As mentioned above, although embodiment of this invention has been explained in full detail using drawing, a concrete structure is not limited to this embodiment, Even if there is a design change in the range which does not deviate from the gist of the present invention. These are included in the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Aluminum alloy clad material, 11 ... Skin material, 11a: Molten metal (Al-Mn aluminum alloy), 11b: Solid-liquid coexistence part (Al-Mn aluminum alloy), 11c: Solid phase part (Al-Mn aluminum alloy), 11d: surface in solid-liquid coexistence state, 12 ... core material, 12a: molten metal (Al-Mg aluminum alloy), 12b: solid-liquid coexistence part (Al-Mg aluminum alloy), 12c: solid phase part (Al-Mg aluminum alloy) ), 30: Aluminum alloy clad manufacturing apparatus, 31: First molten nozzle, 32: Second molten nozzle, 34: Separation plate, 36: Water cooling jacket, 37: Block, 38: Plate, 39: Cylinder, W: Cooling water

Claims (3)

A method for producing an aluminum alloy clad material in which a skin material made of an Al-Mn aluminum alloy is coated on both surfaces of a core material made of an Al-Mg aluminum alloy,
In the manufacturing method, the core is obtained by pouring a molten Al-Mg aluminum alloy serving as the core material between a pair of skin materials in which at least the facing Al-Mn aluminum alloy is in a solid-liquid coexistence state. A method for producing an aluminum alloy clad material characterized by casting a material.   2. A pair of skin materials in which the opposed surfaces are in the solid-liquid coexistence state are cast by flowing a molten Al-Mn aluminum alloy serving as the skin material at opposing positions. The manufacturing method of the aluminum alloy clad as described in 2.   Using an aluminum alloy in which Mg contained in the Al-Mg-based aluminum alloy is in the range of 4.5 to 5.5 mass%, Mn contained in the Al-Mn-based aluminum alloy is 1.0 to 3 The method for producing an aluminum alloy clad material according to claim 1 or 2, wherein an aluminum alloy in the range of 0.0 mass% is used.

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