Method for manufacturing an aluminum alloy clad material for press forming, aluminum alloy clad material for press forming, and press-formed product

Abstract

A method for manufacturing an aluminum alloy clad material for press forming, the aluminum alloy clad material for press forming including a core material, and a first skin material and a second skin material joined to both sides of the core material to sandwich the core material, the method including: Step A, preparing a first aluminum alloy by using a discarded aluminum alloy clad material for a vehicle heat exchanger containing Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti as additive elements; Step B, preparing a second aluminum alloy in which at least a content ratio of Si and Cu is lower than that in the first aluminum alloy; Step C, forming a sheet for the core material by using the first aluminum alloy; Step D, independently forming a sheet for the first skin material and a sheet for the second skin material by using the second aluminum alloy; and Step E, rolling the sheet for the first skin material and the sheet for the second skin material in a state in which the sheet for the first skin material and the sheet for the second skin material are arranged to sandwich the sheet for the core material.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an aluminum alloy clad material for compression molding, an aluminum alloy clad material for compression molding, and a compression molded product. More specifically, it relates to a method for manufacturing an aluminum alloy clad material for compression molding with superior recycling efficiency compared to the prior art, an aluminum alloy clad material for compression molding manufactured by the method, and a compression molded product manufactured using the aluminum alloy clad material for compression molding. Background Technology

[0002] In recent years, the demand for recycled resources has been increasing across various sectors. Since aluminum alloys produced from reduced bauxite consume a significant amount of electricity, recycling is essential from the perspectives of resource conservation and cost reduction.

[0003] For example, Patent Document 1 discloses a recycling method comprising: melting recycled aluminum alloy into liquid metal; adding magnesium, silicon, or copper as alloying elements to the liquid metal to form a modified liquid metal; casting the modified liquid metal; and rolling the cast alloy, wherein the modified liquid metal contains 50% or more recycled aluminum alloy. According to the recycling method described in Patent Document 1, metal products with high strength and high formability can be cast from aluminum alloy scrap.

[0004] Reference List Patent documents Patent document 1: JP2020-514556A (JP7163304B). Summary of the Invention

[0005] Technical issues The inventors have investigated ways to improve recycling efficiency by limiting the amount of aluminum alloy material to be recycled and by limiting the amount of aluminum alloy material to be manufactured. When the same material is simply recycled repeatedly, there is a problem of increased impurity concentration, and when the material is repeatedly recycled to the same alloy composition, the amount of primary aluminum to be added increases, resulting in decreased recycling efficiency.

[0006] The present invention aims to provide a method for manufacturing aluminum alloy cladding materials for compression molding that improves recycling efficiency. Another object of the present invention is to provide an aluminum alloy cladding material for compression molding that can be manufactured by this method, and a compression-molded product manufactured using the aluminum alloy cladding material for compression molding.

[0007] Solution to the problem According to embodiments of the present invention, solutions described in the following projects are provided.

[0008] [Project 1] A method for manufacturing an aluminum alloy cladding material for compression molding, the aluminum alloy cladding material for compression molding comprising a core material, and a first cladding material and a second cladding material joined to both sides of the core material to clamp the core material, the method comprising: Step A: The first aluminum alloy is prepared using waste of aluminum alloy cladding material for vehicle heat exchangers containing Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti as additive elements; Step B: Prepare a second aluminum alloy, wherein the content of Si and Cu in the second aluminum alloy is less than the content of Si and Cu in the first aluminum alloy; Step C: Form a sheet for the core material using the first aluminum alloy; Step D, using a second aluminum alloy to independently form sheets for the first cladding material and sheets for the second cladding material; and Step E involves rolling the sheet material for the first covering material and the sheet material for the second covering material in a state where the sheet material for the core material is clamped.

[0009] In addition to Si and Cu, the additive elements contained in the second aluminum alloy may also include at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn, and Ti. Mn, Cr, Zn, and Ti contribute to the hue and / or material strength after anodizing.

[0010] [Project 2] According to the manufacturing method described in Project 1, the waste aluminum alloy cladding material of the vehicle 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.

[0011] [Project 3] According to the manufacturing method described in Project 1 or 2, the first aluminum alloy contains 10% by mass or more of scrap.

[0012] [Project 4] According to the manufacturing method described in Project 1 or 2, the first aluminum alloy contains 50% by mass or more of scrap.

[0013] [Project 5] According to any one of items 1 to 4, in the manufacturing method, step A includes adding any one of the additive elements and / or primary aluminum, such that the first aluminum alloy comprises Si: 0.50 wt% or more, Fe: 0.05 wt% or more, Cu: 0.12 wt% or more, Mn: 0.60 wt% or more, Mg: 0.30 wt% or more, Cr: 0.01 wt% or more, Zn: 0.11 wt% or more, and Ti: 0.01 wt% or more, with the balance being aluminum and unavoidable impurities.

[0014] [Project 6] According to the manufacturing method described in Project 5, step A includes the step of adding any one of the additive elements and / or primary aluminum, such that the first aluminum alloy contains Si: 2.00 wt% or less, Fe: 1.00 wt% or less, Cu: 1.00 wt% or less, Mn: 1.80 wt% or less, Mg: 0.80 wt% or less, Cr: 0.03 wt% or less, Zn: 1.50 wt% or less, and Ti: 0.30 wt% or less.

[0015] [Project 7] According to any one of items 1 to 6, the sheet for the first cladding material and the sheet for the second cladding material are formed by dividing a sheet for the cladding material formed using a second aluminum alloy.

[0016] [Project 8] An aluminum alloy cladding material for compression molding, comprising: Core material; and A first covering material and a second covering material are joined to both sides of the core material to clamp the core material, wherein, The core material is formed of an aluminum alloy containing, as additive elements, Si: 0.50 wt% or more, Fe: 0.05 wt% or more, Cu: 0.12 wt% or more, Mn: 0.60 wt% or more, Mg: 0.30 wt% or more, Cr: 0.01 wt% or more, Zn: 0.11 wt% or more, and Ti: 0.01 wt% or more, with the balance being aluminum and unavoidable impurities. The first cladding material and the second cladding material are each independently formed of aluminum alloy, wherein the content of Si and Cu in the aluminum alloy is less than that in the core material.

[0017] In addition to Si and Cu, the first coating material and the second coating material may also contain at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn and Ti.

[0018] [Project 9] According to the cladding material described in Project 8, 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.

[0019] [Project 10] A compression-molded product manufactured using an aluminum alloy cladding material for compression molding as described in item 8 or 9.

[0020] [Project 11] The manufacturing method according to any one of items 1 to 7, wherein the waste material of the pressed product according to item 10 is used instead of the waste material of the aluminum alloy cladding material of the vehicle heat exchanger.

[0021] Beneficial effects of the invention According to one embodiment of the present invention, a method for manufacturing an aluminum alloy cladding material for compression molding can be provided, which can improve recycling efficiency. According to another embodiment of the present invention, a compression molded aluminum alloy cladding material that can be manufactured by the manufacturing method, and a compression molded product manufactured using the compression molded aluminum alloy cladding material can be provided. Detailed Implementation

[0022] The following describes a method for manufacturing an aluminum alloy cladding material for compression molding, the aluminum alloy cladding material for compression molding, and a compression molded product according to embodiments of the present invention.

[0023] The method for manufacturing aluminum alloy cladding material for compression molding according to an embodiment of the present invention improves recycling efficiency by using waste aluminum alloy cladding material from vehicle heat exchangers as raw materials for recycling aluminum alloys.

[0024] The aluminum alloy cladding material for compression molding manufactured by the manufacturing method according to an embodiment of the present invention includes a core material, and a first cladding material and a second cladding material joined to both sides of the core material to clamp the core material. The manufacturing method according to an embodiment of the present invention includes the following steps.

[0025] A first aluminum alloy is prepared using waste aluminum alloy cladding material from vehicle heat exchangers containing Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti as additive elements. Using the first aluminum alloy, a sheet material for forming the core material is formed.

[0026] A second aluminum alloy is prepared, wherein the content of Si and Cu in the second aluminum alloy is less than that in the first aluminum alloy. Using the second aluminum alloy, a sheet for forming the first cladding material and a sheet for forming the second cladding material are formed. The second aluminum alloy used to form the sheet for the first cladding material and the sheet for the second cladding material can be selected independently. That is, the sheet for the first cladding material and the sheet for the second cladding material can have different compositions or the same compositions. From a productivity point of view, the sheet for the first cladding material and the sheet for the second cladding material are preferably formed by dividing a sheet for the cladding material formed using the second aluminum alloy.

[0027] The sheet metal for the first cladding material and the sheet metal for the second cladding material are rolled while being clamped between the sheet metal for the core material. The rolling step can be a hot rolling step and / or a cold rolling step. Through the rolling step, a pressed aluminum alloy cladding material comprising the core material, the first cladding material, and the second cladding material is obtained. The obtained pressed aluminum alloy cladding material can be heat-treated as needed.

[0028] Examples of heat treatment include four types: homogenization treatment performed after ingot manufacturing and before hot rolling; intermediate heat treatment performed after hot rolling and before cold rolling; solution treatment performed after cold rolling; and artificial aging treatment performed after solution treatment. Note that intermediate heat treatment can be omitted.

[0029] Heat treatment is performed to uniformly disperse small crystalline precipitates, thereby improving the formability of aluminum alloy sheets for pressing.

[0030] For example, homogenization is performed at temperatures above the solid solubility limit of approximately 500°C or higher, and below approximately 600°C, for approximately 24 hours or less. When the treatment time exceeds approximately 24 hours, the crystal precipitates may become coarser. Furthermore, when the treatment temperature is below approximately 500°C, time is required and throughput is reduced.

[0031] Intermediate heat treatment is performed, for example, at about 300°C or higher and about 500°C or lower, preferably about 400°C. The heat treatment time is, for example, about 2 hours or longer and about 24 hours or less. Intermediate heat treatment reduces the size of crystal precipitates formed during the hot rolling step, reduces strain generated during the hot rolling step, and enables recrystallization. Intermediate heat treatment may be omitted.

[0032] Solution treatment is performed to fully dissolve the crystalline precipitates generated by heating, rolling, etc. Solution treatment is preferably carried out at a temperature below the solidus line and preferably above the solubility limit. The heat treatment time is, for example, longer than about 0 seconds and 12 hours or less. After solution treatment, cooling by air or water is preferred to prevent the dissolved crystalline precipitates from re-precipitating.

[0033] Artificial aging is performed at a temperature of about 100°C or higher and about 200°C or lower for about 4 hours or longer and about 24 hours or less. By utilizing artificial aging to precipitate elements contained in the solid solution in a supersaturated state, the strength can be made close to the target strength.

[0034] The steps for preparing the first aluminum alloy will be described. The first aluminum alloy is used to form a sheet for the core material, which will become the core material for the aluminum alloy cladding material used in pressing. As the first aluminum alloy, scrap of aluminum alloy cladding material from a vehicle heat exchanger containing Si, Fe, Cu, Mn, Mg, Cr, Zn, and Ti as additive elements is used. The scrap of aluminum alloy cladding material from the vehicle heat exchanger, for example, contains Si: 0.50 wt% or more, Fe: 0.10 wt% or more, Cu: 0.10 wt% or more, Mn: 0.50 wt% or more, Mg: 0.05 wt% or more, Cr: 0.01 wt% or more, Zn: 0.10 wt% or more, and Ti: 0.01 wt% or more. The composition of the scrap is determined by melting the scrap and following the method according to JISH 1351-1972.

[0035] Adding any one of the additive elements and / or primary aluminum to the scrap such that the first aluminum alloy comprises, for example, 0.50 wt% or more Si, 0.05 wt% or more Fe, 0.12 wt% or more Cu, 0.60 wt% or more Mn, 0.30 wt% or more Mg, 0.01 wt% or more Cr, 0.11 wt% or more Zn, and 0.01 wt% or more Ti, with the balance being aluminum and unavoidable impurities. Furthermore, adding any one of the additive elements and / or primary aluminum to the scrap such that the first aluminum alloy comprises, for example, 2.00 wt% or less Si, 1.00 wt% or less Fe, 1.00 wt% or less Cu, 1.80 wt% or less Mn, 0.80 wt% or less Mg, 0.03 wt% or less Cr, 1.50 wt% or less Zn, and 0.30 wt% or less Ti.

[0036] The first aluminum alloy preferably contains 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more of scrap. The higher the mass fraction of scrap, the smaller the amount of primary aluminum to be added.

[0037] The content of at least Si and Cu in the second aluminum alloy (also referred to as the second content) is less than the content of Si and Cu in the first aluminum alloy (also referred to as the first content). The at least Si and Cu in the second aluminum alloy includes at least Si and Cu, the content of which increases with the amount of scrap from the press-formed product manufactured using the aluminum alloy cladding material for press forming. In addition to Si and Cu, the additive elements in the second aluminum alloy may also include at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn, and Ti. In this case, the content of any one or more additive elements from the group consisting of Fe, Mn, Mg, Cr, Zn, and Ti (the second content) in the second aluminum alloy may be less than the content in the first aluminum alloy (the first content), or the content of at least one element selected from the group consisting of Fe, Mn, Mg, Cr, Zn, and Ti, excluding Si and Cu, may not be less than the first content.

[0038] According to the above manufacturing method, an aluminum alloy cladding material for compression molding can be obtained, comprising: a core material; and a first cladding material and a second cladding material, which are joined to both sides of the core material to clamp the core material, wherein the core material is formed of an aluminum alloy containing, as additive elements, Si: 0.50 wt% or more, Fe: 0.05 wt% or more, Cu: 0.12 wt% or more, Mn: 0.60 wt% or more, Mg: 0.30 wt% or more, Cr: 0.01 wt% or more, Zn: 0.11 wt% or more, and Ti: 0.01 wt% or more, with the balance being aluminum and unavoidable impurities, and the first cladding material and the second cladding material are each independently formed of an aluminum alloy, wherein the content of at least Si and Cu in the aluminum alloy is less than the content of Si and Cu in the core material. The aluminum alloy of the core material 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.

[0039] In the overall aluminum alloy cladding material for pressing, the content of at least Si and Cu in each added element of the first aluminum alloy is adjusted to not exceed the upper limit of the first content. Therefore, even when the waste from the pressed product manufactured using the aluminum alloy cladding material for pressing contains impurities and the content of at least Si and Cu in the waste increases, it is possible to suppress or reduce the amount exceeding the upper limit of the first content. Therefore, in the above-described method for manufacturing the cladding material, when the waste from the pressed product manufactured using the above-described aluminum alloy cladding material for pressing replaces the waste from the aluminum alloy cladding material for the vehicle heat exchanger, it is possible to reduce the amount of primary aluminum required to prepare the first aluminum alloy and improve recycling efficiency.

[0040] In the method for manufacturing aluminum alloy cladding material for compression molding according to an embodiment of the present invention, the first content and the second content are based on the thickness of the core material, the thickness of the first cladding material and the second cladding material, the required properties of the core material, the first cladding material and the second cladding material, and the content of additive elements including at least Si and Cu that will be excessively included in the waste.

[0041] The core material has a thickness of, for example, 0.1 mm or more and 10.0 mm or less, and the first and second covering materials each have a thickness of, for example, 0.005 mm or more and 3 mm or less. The covering material has a thickness of, for example, about 5% or more and about 30% or less of the core material thickness.

[0042] The composition of the first aluminum alloy is, for example: Si: 0.50% by mass or more and 2.00% by mass or less, Fe: 0.05% by mass or more and 1.00% by mass or less, Cu: 0.12% by mass or more and 1.00% by mass or less, Mn: 0.60% by mass or more and 1.80% by mass or less, Mg: 0.30% by mass or more and 0.80% by mass or less, Cr: 0.01% by mass or more and 0.03% by mass or less, Zn: 0.11% by mass or more and 1.50% by mass or less, and Ti: 0.01% by mass or more and 0.30% by mass or less.

[0043] When the added elements Si and Cu are excessively included in the first aluminum alloy due to the use of scrap, the composition of the second aluminum alloy is, for example: Si: 0.20% by mass or more and 1.00% by mass or less, Fe: more than 0.0% by mass and 0.50% by mass or less, Cu: more than 0.0% by mass and 0.30% by mass or less, and Mg: 0.20% by mass or more and 1.00% by mass or less.

[0044] When the first and second cladding materials are to exhibit improved compressibility (surface quality) and / or improved surface treatability, the composition of the second aluminum alloy can be adjusted, for example, as follows: Si: 0.30% by mass or more and 0.70% by mass or less, Fe: more than 0.0% by mass and 0.40% by mass or less, Cu: more than 0.0% by mass and 0.15% by mass or less, and Mg: 0.30% by mass or more and 0.70% by mass or less.

[0045] The second aluminum alloy may not contain any of the aforementioned additive elements. In the second aluminum alloy, the content of one or more additive elements that would be excessively present in the scrap may be less than the content of one or more additive elements in the first aluminum alloy. Depending on the desired properties of the first and second cladding materials, the second aluminum alloy may contain one or more additive elements (e.g., Zn, Mn, Cr, Ti, Ga, and Ni) in greater quantities than those in the first aluminum alloy. Furthermore, both the first and second aluminum alloys may contain additive elements other than those exemplified.

[0046] The aluminum alloy cladding material for pressing according to embodiments of the present invention can be manufactured by known methods (e.g., see JPH01-252759A). The entire disclosure of JPH01-252759A is incorporated herein by reference. The melting, casting, rolling, and heat treatment (annealing, etc.) of aluminum alloy raw materials, including scrap, can be performed by known methods.

[0047] The aluminum alloy cladding material for compression molding according to embodiments of the present invention is suitable for manufacturing various compression molded products (e.g., automotive housings such as bumpers and front panels, and housings for electronic devices such as smartphones, tablets, and laptops). Furthermore, waste from compression molded products manufactured using the aluminum alloy cladding material for compression molding according to embodiments of the present invention is suitable for manufacturing the aluminum alloy cladding material for compression molding according to embodiments of the present invention.

[0048] Industrial applicability The method for manufacturing aluminum alloy cladding material for compression molding, the aluminum alloy cladding material for compression molding, and the compression molded product according to embodiments of the present invention can improve the recycling efficiency of aluminum alloy materials. Embodiments of the present invention can be combined with known recycling methods, such as the recycling method described in Patent Document 1.

Claims

1. A method for manufacturing an aluminum alloy cladding material for press forming, the aluminum alloy cladding material for press forming comprising a core material, and a first cladding material and a second cladding material joined to both sides of the core material to clamp the core material, the method comprising: Step A: The first aluminum alloy is prepared using waste of aluminum alloy cladding material for vehicle heat exchangers containing Si, Fe, Cu, Mn, Mg, Cr, Zn and Ti as additive elements; Step B: Prepare a second aluminum alloy, wherein the content of Si and Cu in the second aluminum alloy is less than the content of Si and Cu in the first aluminum alloy; Step C: Use the first aluminum alloy to form a sheet for the core material; Step D: Using the second aluminum alloy, sheet materials for the first cladding material and sheet materials for the second cladding material are formed independently of each other; as well as Step E involves rolling the sheet material for the first covering material and the sheet material for the second covering material in a state where they are positioned to clamp the sheet material for the core material.

2. The manufacturing method according to claim 1, wherein, The scrap aluminum alloy cladding material of the vehicle 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.

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

4. The manufacturing method according to claim 1 or 2, wherein, The first aluminum alloy contains 50% by mass or more of the scrap.

5. The manufacturing method according to claim 1 or 2, wherein, Step A includes adding any of the added elements and / or primary aluminum, such that the first aluminum alloy comprises Si: 0.50 wt% or more, Fe: 0.05 wt% or more, Cu: 0.12 wt% or more, Mn: 0.60 wt% or more, Mg: 0.30 wt% or more, Cr: 0.01 wt% or more, Zn: 0.11 wt% or more, and Ti: 0.01 wt% or more, with the balance being aluminum and unavoidable impurities.

6. The manufacturing method according to claim 5, wherein, Step A includes adding any of the added elements and / or the primary aluminum, such that the first aluminum alloy contains Si: 2.00 wt% or less, Fe: 1.00 wt% or less, Cu: 1.00 wt% or less, Mn: 1.80 wt% or less, Mg: 0.80 wt% or less, Cr: 0.03 wt% or less, Zn: 1.50 wt% or less, and Ti: 0.30 wt% or less.

7. The manufacturing method according to claim 1 or 2, wherein, The sheet material for the first cladding material and the sheet material for the second cladding material are formed by dividing a sheet material for cladding material formed using the second aluminum alloy.

8. An aluminum alloy cladding material for compression molding, comprising: core material; as well as A first covering material and a second covering material are joined to both sides of the core material to clamp the core material, wherein... The core material is formed of an aluminum alloy comprising, as additive elements, 0.50% or more Si, 0.05% or more Fe, 0.12% or more Cu, 0.60% or more Mn, 0.30% or more Mg, 0.01% or more Cr, 0.11% or more Zn, and 0.01% or more Ti, with the balance being aluminum and unavoidable impurities. The first coating material and the second coating material are each independently formed of an aluminum alloy, wherein the content of Si and Cu in the aluminum alloy is less than the content of Si and Cu in the core material.

9. The coating material according to claim 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.

10. A compression-molded product manufactured using an aluminum alloy cladding material for compression molding as described in claim 8 or 9.

11. The manufacturing method according to claim 1, wherein, The waste material of the compression-molded product as described in claim 10 is used to replace the waste material of the aluminum alloy cladding material of the vehicle heat exchanger.