JP2025076873A - Manufacturing method of aluminum alloy clad material for press molding, aluminum alloy clad material for press molding, and press molded product - Google Patents

Abstract

To provide a method for manufacturing an aluminum alloy clad material for press molding which can improve recycling efficiency.SOLUTION: A method for manufacturing an aluminum alloy clad material for press molding having a first skin material and a second skin material joined to both sides of core materials so as to sandwich the core materials, includes: a step A of preparing a first aluminum alloy, using a scrap of an aluminum alloy clad material of a heat exchanger for an automobile, which includes Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti as additional elements; a step B of preparing a second aluminum alloy having percentage contents of at least Si and Cu less than percentage contents in the first aluminum alloy; a step C of forming a plate material for a core material, using the first aluminum alloy; a step D of each independently forming a plate material for a first skin material and a plate material for a second skin material, using the second aluminum alloy; and a step E of rolling the plate materials in a state in which the plate material for the first skin material and the plate material for the second skin material are arranged so as to sandwich the plate materials for the core material.SELECTED DRAWING: None

Description

The present invention relates to a manufacturing method for aluminum alloy clad material for press molding, an aluminum alloy clad material for press molding, and a press molded product, and in particular to a manufacturing method for aluminum alloy clad material for press molding that has better recycling efficiency than conventional methods, an aluminum alloy clad material for press molding manufactured by such a manufacturing method, and a press molded product manufactured using such an aluminum alloy clad material for press molding.

In recent years, there has been an increasing demand for recycling resources in various fields. Aluminum alloys, which are produced by reducing bauxite, consume a huge amount of electricity, so there is a demand to promote recycling from the perspective of resource conservation and cost reduction.

For example, Patent Document 1 discloses a recycling method including the steps of melting recycled aluminum alloy into liquid metal, adding magnesium, silicon, or copper as an alloying element to the liquid metal to form a modified liquid metal, casting the modified liquid metal, and rolling the cast alloy, characterized in that the modified liquid metal contains 50% or more recycled aluminum alloy. According to the recycling method described in Patent Document 1, it is possible to cast a metal product with high strength and high formability from aluminum alloy scrap.

Special Publication No. 2020-514556 (Patent No. 7163304)

The inventors have investigated ways to improve recycling efficiency by limiting the scrap aluminum alloy materials to be recycled and the aluminum alloy materials to be produced by recycling. Simply repeatedly recycling the same type of material increases the impurity concentration, and repeatedly recycling the same alloy composition increases the amount of virgin aluminum added, resulting in a decrease in recycling efficiency.

The present invention aims to provide a method for producing an aluminum alloy clad material for press molding that can improve recycling efficiency. The present invention also aims to provide an aluminum alloy clad material for press molding that can be produced by such a production method, and a press-molded product produced using such an aluminum alloy clad material for press molding.

According to an embodiment of the present invention, the following solutions are provided:

[Item 1]
A method for producing an aluminum alloy clad material for press molding, comprising: a core material; and a first skin material and a second skin material joined to both sides of the core material so as to sandwich the core material, the method comprising the steps of:
A step A of preparing a first aluminum alloy using scrap of an aluminum alloy clad material of an automobile heat exchanger, the scrap containing Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti as additive elements;
A step B of preparing a second aluminum alloy having a content rate of at least Si and Cu less than that of the first aluminum alloy;
A step C of forming a core plate material using the first aluminum alloy;
A step D of forming a first skin plate and a second skin plate using the second aluminum alloy,
a step E of rolling the first skin plate and the second skin plate in a state in which the first skin plate and the second skin plate are arranged so as to sandwich the core plate;
A manufacturing method comprising:

The additive elements contained in the second aluminum alloy may further include at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn, and Ti, in addition to Si and Cu. Mn, Cr, Zn, and Ti contribute to the color tone and/or material strength after anodizing.

[Item 2]
2. The method according to claim 1, wherein the scrap of the aluminum alloy clad material of the automotive heat exchanger contains Si: 0.50% by mass or more, Fe: 0.10% by mass or more, Cu: 0.10% by mass or more, Mn: 0.50% by mass or more, Mg: 0.05% by mass or more, Cr: 0.01% by mass or more, Zn: 0.10% by mass or more, and Ti: 0.01% by mass or more.

[Item 3]
3. The manufacturing method according to item 1 or 2, wherein the first aluminum alloy contains 10% by mass or more of the scrap.

[Item 4]
3. The manufacturing method according to claim 1, wherein the first aluminum alloy contains 50% by mass or more of the scrap.

[Item 5]
5. The manufacturing method according to any one of items 1 to 4, wherein the step A includes a step of adding any one of the additive elements and/or new aluminum ingot so that the first aluminum alloy contains 0.50% by mass or more of Si, 0.05% by mass or more of Fe, 0.12% by mass or more of Cu, 0.60% by mass or more of Mn, 0.30% by mass or more of Mg, 0.01% by mass or more of Cr, 0.11% by mass or more of Zn, and 0.01% by mass or more of Ti, with the remainder being aluminum and unavoidable impurities.

[Item 6]
Item 6. The manufacturing method according to item 5, wherein the step A includes adding any of the additive elements and/or new aluminum ingot so that the first aluminum alloy contains 2.00% by mass or less of Si, 1.00% by mass or less of Fe, 1.00% by mass or less of Cu, 1.80% by mass or less of Mn, 0.80% by mass or less of Mg, 0.03% by mass or less of Cr, 1.50% by mass or less of Zn, and 0.30% by mass or less of Ti.

[Item 7]
7. The manufacturing method according to any one of items 1 to 6, wherein the first skin plate and the second skin plate are formed by dividing one skin plate formed using the second aluminum alloy.

[Item 8]
1. An aluminum alloy clad material for press molding, comprising a core material and a first skin material and a second skin material joined to both sides of the core material so as to sandwich the core material,
the core material is formed of an aluminum alloy containing, as additive elements, 0.50% by mass or more of Si, 0.05% by mass or more of Fe, 0.12% by mass or more of Cu, 0.60% by mass or more of Mn, 0.30% by mass or more of Mg, 0.01% by mass or more of Cr, 0.11% by mass or more of Zn, and 0.01% by mass or more of Ti, with the remainder being aluminum and unavoidable impurities;
The first skin material and the second skin material are each independently formed of an aluminum alloy having a content of at least Si and Cu less than that of the core material.
Clad material.

The first skin material and the second skin material may further contain at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn and Ti in addition to Si and Cu.

[Item 9]
9. The clad material according to item 8, wherein the aluminum alloy of the core material contains Si: 2.00% by mass or less, Fe: 1.00% by mass or less, Cu: 1.00% by mass or less, Mn: 1.80% by mass or less, Mg: 0.80% by mass or less, Cr: 0.03% by mass or less, Zn: 1.50% by mass or less, and Ti: 0.30% by mass or less.

[Item 10]
10. A press-molded product produced using the aluminum alloy clad material for press molding according to item 8 or 9.

[Item 11]
The manufacturing method according to any one of items 1 to 7, wherein scrap of the press-molded product according to item 10 is used instead of the scrap of the aluminum alloy clad material of the automotive heat exchanger.

According to an embodiment of the present invention, a method for producing an aluminum alloy clad material for press molding that can improve recycling efficiency is provided. According to another embodiment of the present invention, an aluminum alloy clad material for press molding that can be produced by such a production method, and a press-molded product produced using such an aluminum alloy clad material for press molding are provided.

The following describes a method for producing an aluminum alloy clad material for press molding, an aluminum alloy clad material for press molding, and a press molded product according to an embodiment of the present invention.

The method for producing press-molded aluminum alloy clad material according to an embodiment of the present invention improves recycling efficiency by using scrap aluminum alloy clad material from automotive heat exchangers as the recycled aluminum alloy raw material.

The press-molding aluminum alloy clad material manufactured by the manufacturing method according to an embodiment of the present invention has a core material and a first skin material and a second skin material joined to either side of the core material so as to sandwich the core material. The manufacturing method according to an embodiment of the present invention includes the following steps.

A first aluminum alloy is prepared using scrap of an aluminum alloy clad material for an automobile heat exchanger, the scrap containing Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti as additive elements. The first aluminum alloy is used to form a core plate material for forming a core material.

A second aluminum alloy is prepared, the content of at least Si and Cu being less than the content in the first aluminum alloy. The second aluminum alloy is used to form a first skin plate for forming the first skin and a second skin plate for forming the second skin. The second aluminum alloy for forming the first skin plate and the second skin plate can be selected independently. That is, the compositions of the first skin plate and the second skin plate may be different from each other or the same. From the viewpoint of productivity, it is preferable to form the first skin plate and the second skin plate by dividing one skin plate formed using the second aluminum alloy.

The first skin plate and the second skin plate are arranged so as to sandwich the core plate and are rolled. The rolling process may be a hot rolling process and/or a cold rolling process. After the rolling process, an aluminum alloy clad material for press molding having a core material, a first skin material, and a second skin material is obtained. The obtained aluminum alloy clad material for press molding may be subjected to a heat treatment as necessary.

Examples of heat treatments include homogenization treatment, which is performed after ingot casting and before the hot rolling process; intermediate heat treatment, which is performed after the hot rolling process and before the cold rolling process; solution treatment, which is performed after the cold rolling process; and artificial aging treatment, which is performed after the solution treatment. Note that the intermediate heat treatment may be omitted.

Heat treatment is carried out to uniformly disperse small crystal precipitates in order to improve the formability of the aluminum alloy sheet for press forming.

The homogenization treatment is carried out, for example, at a temperature of about 500°C to about 600°C, which is higher than the solubility limit, for about 24 hours or less. If the treatment exceeds about 24 hours, the crystal precipitates may become coarse. Furthermore, if the treatment temperature is less than about 500°C, it takes a long time and the throughput decreases.

The intermediate heat treatment is performed, for example, at about 300°C to about 500°C, preferably about 400°C. The heat treatment time is, for example, about 2 hours to about 24 hours. The intermediate heat treatment reduces the size of the crystal precipitates produced in the hot rolling process, and reduces the distortion caused in the hot rolling process, allowing recrystallization. The intermediate heat treatment may be omitted.

Solution treatment is performed to heat the crystal precipitates generated by rolling or the like to fully dissolve them. The solution treatment is preferably performed at a temperature lower than the solidus and preferably higher than the solubility limit line. The heat treatment time is, for example, more than about 0 seconds and not more than 12 hours. After the solution treatment, it is preferable to cool the material by air or water to prevent the dissolved crystal precipitates from re-precipitating.

Artificial aging is performed at a temperature of about 100°C to about 200°C for about 4 hours to about 24 hours. By using artificial aging, the elements contained in the solid solution in a supersaturated state are precipitated, allowing the material to approach the desired strength.

The process of preparing the first aluminum alloy will be described. The first aluminum alloy is used to form a core plate material that will be the core material of the aluminum alloy clad material for press molding. Scrap of an aluminum alloy clad material for an automobile heat exchanger, which contains Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti as additive elements, is used for the first aluminum alloy. The scrap of an aluminum alloy clad material for an automobile heat exchanger contains, for example, Si: 0.50 mass% or more, Fe: 0.10 mass% or more, Cu: 0.10 mass% or more, Mn: 0.50 mass% or more, Mg: 0.05 mass% or more, Cr: 0.01 mass% or more, Zn: 0.10 mass% or more, and Ti: 0.01 mass% or more. The composition of the scrap is determined by melting the scrap and following a method conforming to JIS H 1351-1972.

Any of the additive elements and/or virgin aluminum ingot are added to the scrap so that the first aluminum alloy contains, for example, Si: 0.50 mass% or more, Fe: 0.05 mass% or more, Cu: 0.12 mass% or more, Mn: 0.60 mass% or more, Mg: 0.30 mass% or more, Cr: 0.01 mass% or more, Zn: 0.11 mass% or more, and Ti: 0.01 mass% or more, with the remainder consisting of aluminum and unavoidable impurities. In addition, any of the above-mentioned additive elements and/or new aluminum ingot are added to the scrap so that the first aluminum alloy contains, for example, Si: 2.00 mass% or less, Fe: 1.00 mass% or less, Cu: 1.00 mass% or less, Mn: 1.80 mass% or less, Mg: 0.80 mass% or less, Cr: 0.03 mass% or less, Zn: 1.50 mass% or less, and Ti: 0.30 mass% or less.

The first aluminum alloy preferably contains 10% by mass or more of scrap, more preferably 30% by mass or more, and even more preferably 50% by mass or more. The greater the mass fraction of scrap, the less virgin aluminum ingot can be added.

The content of at least Si and Cu in the second aluminum alloy (sometimes referred to as the second content) is less than the content in the first aluminum alloy (sometimes referred to as the first content). At least Si and Cu in the second aluminum alloy include at least Si and Cu whose content increases due to scrap of a press-molded product manufactured using an aluminum alloy clad material for press molding. The additive elements in the second aluminum alloy may further include at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn and Ti in addition to Si and Cu. In this case, the content (second content) of any one or more additive elements of Fe, Mn, Mg, Cr, Zn and Ti in the second aluminum alloy may be smaller than the content (first content) in the first aluminum alloy, and the content of at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn and Ti other than Si and Cu may not be smaller than the first content.

According to the above manufacturing method, an aluminum alloy clad material for press molding is obtained, which has a core material and a first skin material and a second skin material joined to either side of the core material so as to sandwich the core material, in which the core material contains, as additive elements, the following: Si: 0.50% by mass or more, Fe: 0.05% by mass or more, Cu: 0.12% by mass or more, Mn: 0.60% by mass or more, Mg: 0.30% by mass or more, Cr: 0.01% by mass or more, Zn: 0.11% by mass or more, and Ti: 0.01% by mass or more, with the remainder being formed of an aluminum alloy consisting of aluminum and unavoidable impurities, and the first skin material and the second skin material are each independently formed of an aluminum alloy in which the content of at least Si and Cu is less than the content in the core material. The aluminum alloy core contains, for example, Si: 2.00% by mass or less, Fe: 1.00% by mass or less, Cu: 1.00% by mass or less, Mn: 1.80% by mass or less, Mg: 0.80% by mass or less, Cr: 0.03% by mass or less, Zn: 1.50% by mass or less, and Ti: 0.30% by mass or less.

The content of at least Si and Cu of each additive element of the first aluminum alloy in the entire aluminum alloy clad material for press molding is adjusted so as not to exceed the upper limit of the first content. Therefore, even if impurities are contained in the scrap of the press-molded product manufactured using the aluminum alloy clad material for press molding and the content of at least Si and Cu contained in the scrap increases, it is possible to suppress the content from exceeding the upper limit of the first content, or to reduce the amount by which the content exceeds the upper limit of the first content. Therefore, in the manufacturing method of the clad material, by using scrap of the press-molded product manufactured using the aluminum alloy clad material for press molding instead of scrap of the aluminum alloy clad material of the automobile heat exchanger, it is possible to reduce the amount of new aluminum ingot required to prepare the first aluminum alloy, and to improve recycling efficiency.

The first and second content rates in the method for producing an aluminum alloy clad material for press molding according to an embodiment of the present invention depend on the thickness of the core material, the thickness of the first and second skin materials, and the properties required for the core material, the first and second skin materials, and the content of additive elements, including at least Si and Cu, that will be contained in excess in the scrap.

The thickness of the core material is, for example, 0.1 mm or more and 10.0 mm or less, and the thicknesses of the first skin material and the second skin material are each, independently, for example, 0.005 mm or more and 3 mm or less. The thickness of the skin material is, for example, about 5% or more and about 30% or less of the thickness of the core material.

The composition of the first aluminum alloy is, for example,
Si: 0.50 mass% or more and 2.00 mass% or less Fe: 0.05 mass% or more and 1.00 mass% or less Cu: 0.12 mass% or more and 1.00 mass% or less Mn: 0.60 mass% or more and 1.80 mass% or less Mg: 0.30 mass% or more and 0.80 mass% or less Cr: 0.01 mass% or more and 0.03 mass% or less Zn: 0.11% by mass or more and 1.50% by mass or less Ti: 0.01% by mass or more: 0.30% by mass or less.

In the case where the additive elements to be contained in the first aluminum alloy by using the scrap are Si and Cu, the composition of the second aluminum alloy is, for example,
Si: 0.20 mass% or more and 1.00 mass% or less Fe: More than 0.0 mass% and 0.50 mass% or less Cu: More than 0.0 mass% and 0.30 mass% or less Mg: 0.20 mass% or more and 1.00 mass% or less.

In the case where the first skin material and the second skin material are intended to have the effect of improving press moldability (surface quality) and/or improving surface treatability, the composition of the second aluminum alloy can be adjusted, for example, as follows.
Si: 0.30 mass% or more and 0.70 mass% or less Fe: More than 0.0 mass% and 0.40 mass% or less Cu: More than 0.0 mass% and 0.15 mass% or less Mg: 0.30 mass% or more and 0.70 mass% or less

The second aluminum alloy may not contain any of the above-mentioned additive elements. In addition, the second aluminum alloy may have a lower content of one or more additive elements that will be contained in the scrap than the content of the one or more additive elements in the first aluminum alloy. Depending on the properties required for the first skin material and the second skin material, the second aluminum alloy may have a higher content of one or more additive elements (e.g., Zn, Mn, Cr, Ti, Ga, or Ni) than the first aluminum alloy. In addition, the first aluminum alloy and the second aluminum alloy may contain additive elements other than the exemplified additive elements.

The press-molding aluminum alloy clad material according to the embodiment of the present invention can be manufactured by known methods (see, for example, JP 01-252759 A). The entire disclosure of JP 01-252759 A is incorporated herein by reference. The melting (dissolving), casting, rolling, and heat treatment (annealing, etc.) of the aluminum alloy raw material including scrap can be carried out by known methods.

The press-molded aluminum alloy clad material according to the embodiment of the present invention can be suitably used for manufacturing various press-molded products (e.g., automobile housings such as bumpers and fronts, housings for electronic devices such as smartphones, tablet terminals, and notebook computers, etc.). Furthermore, scrap of press-molded products manufactured using the press-molded aluminum alloy clad material according to the embodiment of the present invention can be suitably used for manufacturing the press-molded aluminum alloy clad material according to the embodiment of the present invention.

The manufacturing method of the aluminum alloy clad material for press molding, the aluminum alloy clad material for press molding, and the press molded product according to the embodiments of the present invention can improve the recycling efficiency of aluminum alloy materials. The embodiments of the present invention can also be used in combination with known recycling methods, such as the recycling method described in Patent Document 1.

Claims (11)

A method for producing an aluminum alloy clad material for press molding, comprising: a core material; and a first skin material and a second skin material joined to both sides of the core material so as to sandwich the core material, the method comprising the steps of:
A step A of preparing a first aluminum alloy using scrap of an aluminum alloy clad material of an automobile heat exchanger, the scrap containing Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti as additive elements;
A step B of preparing a second aluminum alloy having a content rate of at least Si and Cu less than that of the first aluminum alloy;
A step C of forming a core plate material using the first aluminum alloy;
A step D of forming a first skin plate and a second skin plate using the second aluminum alloy,
A step E of rolling the first skin plate and the second skin plate in a state in which the core plate is sandwiched between the first skin plate and the second skin plate;
A manufacturing method comprising: The manufacturing method according to claim 1, wherein the scrap of the aluminum alloy clad material of the automotive heat exchanger contains Si: 0.50 mass% or more, Fe: 0.10 mass% or more, Cu: 0.10 mass% or more, Mn: 0.50 mass% or more, Mg: 0.05 mass% or more, Cr: 0.01 mass% or more, Zn: 0.10 mass% or more, and Ti: 0.01 mass% or more. The manufacturing method according to claim 1 or 2, wherein the first aluminum alloy contains 10% by mass or more of the scrap. The manufacturing method according to claim 1 or 2, wherein the first aluminum alloy contains 50% by mass or more of the scrap. The manufacturing method according to claim 1 or 2, wherein step A includes a step of adding any of the additive elements and/or new aluminum ingot so that the first aluminum alloy contains Si: 0.50 mass% or more, Fe: 0.05 mass% or more, Cu: 0.12 mass% or more, Mn: 0.60 mass% or more, Mg: 0.30 mass% or more, Cr: 0.01 mass% or more, Zn: 0.11 mass% or more, and Ti: 0.01 mass% or more, with the remainder consisting of aluminum and inevitable impurities. The manufacturing method according to claim 5, wherein step A includes a step of adding any of the additive elements and/or new aluminum ingot so that the first aluminum alloy contains Si: 2.00 mass% or less, Fe: 1.00 mass% or less, Cu: 1.00 mass% or less, Mn: 1.80 mass% or less, Mg: 0.80 mass% or less, Cr: 0.03 mass% or less, Zn: 1.50 mass% or less, and Ti: 0.30 mass% or less. The manufacturing method according to claim 1 or 2, wherein the first skin plate material and the second skin plate material are formed by dividing one skin plate material formed using the second aluminum alloy. 1. An aluminum alloy clad material for press molding, comprising a core material and a first skin material and a second skin material joined to both sides of the core material so as to sandwich the core material,
the core material is formed of an aluminum alloy containing, as additive elements, 0.50% by mass or more of Si, 0.05% by mass or more of Fe, 0.12% by mass or more of Cu, 0.60% by mass or more of Mn, 0.30% by mass or more of Mg, 0.01% by mass or more of Cr, 0.11% by mass or more of Zn, and 0.01% by mass or more of Ti, with the remainder being aluminum and unavoidable impurities;
The first skin material and the second skin material are each independently formed of an aluminum alloy having a content of at least Si and Cu less than that of the core material.
Clad material. The clad material according to claim 8, wherein the aluminum alloy of the core material contains Si: 2.00 mass% or less, Fe: 1.00 mass% or less, Cu: 1.00 mass% or less, Mn: 1.80 mass% or less, Mg: 0.80 mass% or less, Cr: 0.03 mass% or less, Zn: 1.50 mass% or less, and Ti: 0.30 mass% or less. A press-molded product manufactured using the aluminum alloy clad material for press molding according to claim 8 or 9. The manufacturing method according to claim 1 , wherein scrap of the press-molded product according to claim 10 is used in place of the scrap of the aluminum alloy clad material of the heat exchanger for an automobile.