Aluminum alloy drawn material

Abstract

Provided is an aluminum alloy sheet that can be blended with various types of aluminum scraps at a high recycling rate and has excellent mechanical properties and formability. 【Solution means】The aluminum alloy sheet has an aluminum alloy part. The aluminum alloy part contains, in mass% based on the total mass of the aluminum alloy part, Si: 1.0% or more and 7.5% or less, Fe: 0.15% or more and 0.8% or less, and Mn: 0.3% or more and 1.0% or less, and the contents of Cu, Mg, and Zn are regulated to be below predetermined contents. When the contents of Si and Mg in the total mass of the aluminum alloy part are [Si] and [Mg] in mass%, respectively, the value α obtained by the formula (1): α = [Si] - 2×[Mg] is 0 or more, and the value β obtained by the formula (2): β = [Si] + 2.25×[Mg] is 7.5 or less, and the ratio A / B of the number density of precipitate particles is 1.1×10 -3 or more and 5.0×10 -3 or less.

Description

Technical Field

[0001] The present invention relates to an aluminum alloy rolled material.

Background Art

[0002] In recent years, achieving carbon neutrality has become an issue for society as a whole, and various methods for solving the above problems have been studied. For example, from the perspective of resource depletion, recycling of various materials has advanced, and recycling of metals that are consumed in large quantities has been carried out for a long time. For example, aluminum consumes a large amount of electricity during the production of new ingots and emits CO 2 . Therefore, by reducing the amount of new ingots used through recycling, the CO 2 emissions during the production of aluminum alloy materials can be significantly reduced. However, due to the influence of impurities in the scraps used for recycling, there are various problems in applying recycling to rolled materials compared to casting materials. Patent Document 1 proposes a method for producing an aluminum alloy for automotive members in which aluminum alloy casting scraps are added with sash scraps, aluminum can scraps (UBC: Used Beverage Can), or ingots, melted to dilute impurities, and component adjustment is performed as necessary.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even when using the manufacturing method described in Patent Document 1 above, it is necessary to make the Si content in the alloy after component adjustment, for example, 4.85% by mass or less. In addition, when the usage rate of casting part scraps or automotive casting scraps is increased, the elongation and bendability of the obtained aluminum alloy material are significantly reduced.

[0005] The present invention has been made in view of such problems, and is an aluminum alloy sheet that can be manufactured with a high recycling rate using various types of aluminum alloy scraps, and has excellent mechanical properties such as elongation and strength, and particularly has a high formability. The purpose is to provide an aluminum alloy sheet.

Means for Solving the Problems

[0006] The above object of the present invention is achieved by the configuration of the following [1] related to the following aluminum alloy sheet.

[0007] [1] An aluminum alloy sheet having an aluminum alloy part, The aluminum alloy part is based on the total mass of the aluminum alloy part, Si: 1.0% by mass or more and 7.5% by mass or less, Fe: 0.15% by mass or more and 0.8% by mass or less, and Mn: 0.3% by mass or more and 1.0% by mass or less, and contains Cu: 0.5% by mass or less, Mg: 2.0% by mass or less, Zn: 0.7% by mass or less, and The balance consists of Al and unavoidable impurities, When the content of Si in the total mass of the aluminum alloy part is [Si] in mass%, and the content of Mg in the total mass of the aluminum alloy part is [Mg] in mass%, The value α calculated by the following formula (1) is 0 or more, and the value β calculated by the following formula (2) is 7.5 or less, Formula (1): α = [Si] - 2 × [Mg] Formula (2): β = [Si] + 2.25 × [Mg] The aluminum alloy part has precipitate particles, Among the precipitate particles, the number density of precipitate particles having an equivalent circle diameter of 0.1 μm or more is A (pieces / mm 2 ), and the number density of precipitate particles having an equivalent circle diameter of less than 0.1 μm is B (pieces / mm 2) When it is set as such, the ratio A / B of the number density A and the number density B is 1.1×10 -3 or more and 5.0×10 -3 or less, and it is an aluminum alloy drawn material characterized by this.

[0008] Moreover, a preferred embodiment of the present invention related to an aluminum alloy drawn material relates to the following [2] to [4].

[0009] [2] The number density A (pieces / mm 2 ) of precipitate particles having an equivalent circle diameter of 0.1 μm or more is 1.9×10 4 or more and 4.0×10 4 or less, and it is the aluminum alloy drawn material according to [1].

[0010] [3] The number density B (pieces / mm 2 ) of precipitate particles having an equivalent circle diameter of less than 0.1 μm is 3.0×10 6 or more and 2.5×10 7 or less, and it is the aluminum alloy drawn material according to [1] or [2].

[0011] [4] The ratio A / B of the number density A and the number density B is 1.2×10 -3 or more, and it is the aluminum alloy drawn material according to any one of [1] to [3].

Effect of the Invention

[0012] According to the present invention, it is possible to blend various types of aluminum scraps at a high recycling rate, and it is possible to provide an aluminum alloy drawn material having excellent mechanical properties such as elongation and strength, and particularly high formability.

Mode for Carrying Out the Invention

[0013] Aluminum alloy scraps are expected to become difficult to obtain from the market due to the future expansion of demand. Therefore, the inventors of the present application have intensively studied aluminum alloy rolling materials that can be compounded with various alloy scraps without being limited to specific alloy scraps. The structure has a great influence on the mechanical properties of the material, and the Si and Mg contents and their ratios greatly affect the formability of the aluminum alloy material. Also, when there are many precipitate particles with a predetermined equivalent circle diameter or more and few precipitate particles with a diameter less than the predetermined equivalent circle diameter, it leads to a decrease in formability and insufficient strength. On the other hand, when there are few precipitate particles with a predetermined equivalent circle diameter or more and many precipitate particles with a diameter less than the predetermined equivalent circle diameter, it leads to coarsening of the recrystallized grains. Therefore, the inventors of the present application have found the optimal range of the number density of precipitate particles in the aluminum alloy part and the optimal range of the formula representing the balance between the Si content and the Mg content.

[0014] Hereinafter, the aluminum alloy rolling material and its manufacturing method according to the embodiment of the present invention will be described. In this specification, the "aluminum alloy rolling material" may be simply referred to as the "rolling material".

[0015] [Aluminum alloy rolling material] The aluminum alloy rolling material according to this embodiment has an aluminum alloy part having the following alloy composition. Hereinafter, the chemical components contained in the aluminum alloy part in the aluminum alloy rolling material and the reasons for limiting their contents will be described in detail.

[0016] <Aluminum alloy part> (Si: 1.0 mass% or more and 7.5 mass% or less) Si is an element that easily forms Si compounds and Si particles of a size that can serve as recrystallization nuclei. On the other hand, when the Si content becomes excessive, the Si compounds and Si particles are more likely to coarsen, leading to a decrease in elongation and a deterioration in formability. Note that Si is an element contained in various aluminum alloy scraps. In the present embodiment, since the value calculated by a specific formula using the Si content, the number density of precipitate particles, and the ratio A / B of the number density of precipitate particles are defined within an appropriate range, even with a high recycling rate, mechanical properties such as elongation and strength are good, and the formability of the aluminum alloy part can be improved.

[0017] If the Si content in the aluminum alloy part is less than 1.0 mass%, there will be a shortage of precipitates of a size that can serve as recrystallization nuclei. Also, if the Si content in the aluminum alloy part is less than 1.0 mass%, it is necessary to reduce the usage amount of aluminum alloy scraps with a high Si content, and the recycling rate cannot be improved. Therefore, the Si content in the aluminum alloy part should be 1.0 mass% or more based on the total mass of the aluminum alloy part, preferably 1.5 mass% or more, and more preferably 2.0 mass% or more. On the other hand, if the Si content in the aluminum alloy part exceeds 7.5 mass%, large Si compounds and Si particles are likely to be formed, leading to a decrease in elongation and a deterioration in formability. Therefore, the Si content in the aluminum alloy part should be 7.5 mass% or less based on the total mass of the aluminum alloy part, preferably 6.0 mass% or less, and more preferably 5.0 mass% or less.

[0018] (Fe: 0.15 mass% or more and 0.8 mass% or less) Fe is an element that easily forms intermetallic compounds of a size that can serve as recrystallization nuclei. Therefore, when the Fe content is less than 0.15% by mass, there is a shortage of precipitates of a size that can serve as recrystallization nuclei. Also, since aluminum alloy scraps generally contain Fe, in order to make the Fe content in the aluminum alloy part less than 0.15% by mass, it is necessary to use high-purity aluminum ingots, which increases the manufacturing cost. Therefore, the Fe content in the aluminum alloy part is preferably 0.15% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.25% by mass or more with respect to the total mass of the aluminum alloy part. On the other hand, when the Fe content in the aluminum alloy part exceeds 0.8% by mass, large intermetallic compounds are likely to be formed during casting, resulting in a decrease in elongation and a reduction in formability. Therefore, the Fe content in the aluminum alloy part is preferably 0.8% by mass or less, more preferably 0.75% by mass or less, and even more preferably 0.7% by mass or less with respect to the total mass of the aluminum alloy part.

[0019] (Mn: 0.3% by mass or more and 1.0% by mass or less) Mn is an element that has the effect of improving the strength of the aluminum alloy part. When the Mn content in the aluminum alloy part is less than 0.3% by mass, the effect of improving the strength cannot be sufficiently obtained. Therefore, the Mn content with respect to the total mass of the aluminum alloy part is 0.3% by mass or more, preferably 0.4% by mass or more, and more preferably 0.5% by mass or more. On the other hand, when the Mn content in the aluminum alloy part exceeds 1.0% by mass, large intermetallic compounds are likely to be formed during casting, resulting in a decrease in elongation and a reduction in formability. Therefore, the Mn content in the aluminum alloy part is preferably 1.0% by mass or less, more preferably 0.95% by mass or less, and even more preferably 0.9% by mass or less with respect to the total mass of the aluminum alloy part.

[0020] (Cu: 0.5% by mass or less) Cu is an element that affects the strength and formability of the rolled material. Generally, Cu is contained in aluminum alloy scraps. However, in this embodiment, the Cu content in the aluminum alloy part may be 0% by mass. However, when Cu is contained in the aluminum alloy part for the purpose of improving strength, the Cu content in the aluminum alloy part is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, based on the total mass of the aluminum alloy part. On the other hand, when the Cu content in the aluminum alloy part exceeds 0.5% by mass, the elongation decreases, leading to a decrease in formability. Therefore, the Cu content in the aluminum alloy part is 0.5% by mass or less, preferably 0.45% by mass or less, more preferably 0.4% by mass or less, based on the total mass of the aluminum alloy part.

[0021] (Mg: 2.0% by mass or less) Mg is an element that affects the strength and formability of the rolled material. In this embodiment, the Mg content in the aluminum alloy part may be 0% by mass. However, when Mg is contained in the aluminum alloy part for the purpose of improving strength, the Mg content in the aluminum alloy part is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total mass of the aluminum alloy part. On the other hand, when the Mg content in the aluminum alloy part exceeds 2.0% by mass, large Mg compounds are likely to be formed, resulting in a decrease in elongation and a decrease in formability. Therefore, the Mg content in the aluminum alloy part is 2.0% by mass or less, preferably 1.5% by mass or less, more preferably 1.0% by mass or less, based on the total mass of the aluminum alloy part.

[0022] (Zn: 0.7% by mass or less) In this embodiment, Zn contained in the aluminum alloy part may be 0% by mass. However, since Zn is generally contained in aluminum alloy scraps, the Zn content in the aluminum alloy part is considered to be 0.1% by mass or more based on the total mass of the aluminum alloy part. On the other hand, if the Zn content in the aluminum alloy part exceeds 0.7% by mass, the elongation may decrease due to an increase in precipitates such as MgZn2, leading to a decrease in formability. Also, if the Zn content in the aluminum alloy part exceeds 0.7% by mass, the pitting potential becomes lower and the corrosion rate increases. Therefore, the Zn content in the aluminum alloy part is 0.7% by mass or less based on the total mass of the aluminum alloy part, preferably 0.65% by mass or less, and more preferably 0.6% by mass or less.

[0023] (Other elements) In the aluminum alloy sheet according to this embodiment, the total of Al, Si, Fe, Mn, Cu, Mg, and Zn in the aluminum alloy part is preferably 98.5% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more based on the total mass of the aluminum alloy part. In addition, examples of other elements of the above elements include Cr, Zr, Ni, Sn, Sr, Sb, and Ca. Since these elements may be contained in aluminum alloy scraps, they may also be contained in the aluminum alloy part obtained using these alloy scraps. In this embodiment, the contents of Cr, Zr, Ni, Sn, Pb, Sr, Sb, and Ca in the aluminum alloy part are not particularly limited. For example, the Cr content is preferably 0.1% by mass or less, the Zr content is preferably 0.1% by mass or less, the Ni content is preferably 0.2% by mass or less, the Sn content is preferably 0.1% by mass or less, the Sr content is preferably 0.18% by mass or less, the Sb content is preferably 0.5% by mass or less, and the Ca content is preferably 0.1% by mass or less.

[0024] (Balance: Al and inevitable impurities) In the aluminum alloy rolled material according to this embodiment, the remainder of the aluminum alloy part is Al and inevitable impurities. Examples of the inevitable impurities include Na and the like. Note that the Na content in the aluminum alloy part is preferably 0.002% by mass or less with respect to the total mass of the aluminum alloy part. Further, the Al content in the aluminum alloy part is preferably 80% by mass or more with respect to the total mass of the aluminum alloy part, and the total amount of the inevitable impurities in the aluminum alloy part is preferably 0.15% by mass or less with respect to the total mass of the aluminum alloy part.

[0025] Next, an equation using the Si content and the Mg content in the aluminum alloy part, and the crystal grain size will be described.

[0026] (Value α calculated by formula (1): 0 or more) If the Mg content increases too much with respect to the Si content, the strength increases due to the effect of solid solution strengthening or precipitation effect, and the elongation decreases. In this embodiment, the effects of the Si content and the Mg content on the formability are shown in Table (1) below. That is, when the value α calculated by Table (1) below becomes a value smaller than 0, the elongation decreases and the formability of the aluminum alloy part deteriorates. Therefore, the above value α is 0 or more, preferably 0.5 or more, and more preferably 0.75 or more.

[0027] Formula (1): α = [Si] - 2×[Mg]

[0028] (Value β calculated by formula (2): 7.5 or less) When both the Si content and the Mg content are high, 2 the precipitates of Mg Si increase, and the elongation decreases due to the influence of the precipitates. In this embodiment, the influence of the precipitates is shown by the following formula (2). That is, when the value β calculated by the following formula (2) exceeds 7.5, the elongation of the aluminum alloy part decreases. Therefore, the above value β is 7.5 or less, preferably 7.0 or less, and more preferably 6.5 or less.

[0029] Formula (2): β = [Si] + 2.25×[Mg] However, in the above formulas (1) and (2), [Si] is the value representing the content of Si in terms of mass% with respect to the total mass of the aluminum alloy part, and [Mg] is the value representing the content of Mg in terms of mass% with respect to the total mass of the aluminum alloy part.

[0030] (Ratio A / B of the number density of precipitate particles: 1.1×10 -3 or more and 5.0×10 -3 or less) In this embodiment, among the precipitate particles included in the aluminum alloy part, the number density of precipitate particles having an equivalent circle diameter of 0.1 μm or more is A (particles / mm 2 ), and the number density of precipitate particles having an equivalent circle diameter of less than 0.1 μm is B (particles / mm 2 ), and the ratio between the two is defined. Specifically, when the ratio A / B of the number density A to the number density B exceeds 5.0×10 -3 , excessive coarse precipitates leading to strain concentration occur, and the formability deteriorates. Therefore, the ratio A / B of the number density A to the number density B is 5.0×10 -3 or less, preferably 4.5×10 -3 or less, and more preferably 4.0×10 -3 or less. On the other hand, when the ratio A / B of the number density A to the number density B is less than 1.1×10 -3 , the precipitate particles having a size that can serve as nuclei for recrystallization decrease, and the fine crystal grains that suppress recrystallization increase. As a result, the crystal grains coarsen, leading to a decrease in elongation and formability. Therefore, the ratio A / B of the number density A to the number density B is 1.1×10 -3 or more, preferably 1.2×10 -3 or more, more preferably 1.4×10 -3 or more, and even more preferably 1.7×10 -3 or more.

[0031] (Number density A of precipitate particles having an equivalent circle diameter of 0.1 μm or more: 1.9×10 4 particles / mm 2 or more and 4.0×10 4particles / mm 2 or less) Among the precipitate particles in the aluminum alloy part, when the number density A of the precipitate particles having an equivalent circle diameter of 0.1 μm or more is 4.0×10 4 particles / mm 2 or less, the formability can be further improved. Therefore, the number density A of the precipitate particles having an equivalent circle diameter of 0.1 μm or more is preferably 4.0×10 4 particles / mm 2 or less, more preferably 3.7×10 4 particles / mm 2 or less, and even more preferably 3.4×10 4 particles / mm 2 or less. On the other hand, when the number density A of the precipitate particles having an equivalent circle diameter of 0.1 μm or more is 1.9×10 4 particles / mm 2 or more, the coarsening of the crystal grains can be suppressed, and the elongation and formability can be further improved. Therefore, the number density A of the precipitate particles having an equivalent circle diameter of 0.1 μm or more is preferably 1.9×10 4 particles / mm 2 or more, more preferably 2.2×10 4 particles / mm 2 or more, and even more preferably 2.5×10 4 particles / mm 2 or more.

[0032] (Number density B of precipitate particles having an equivalent circle diameter of less than 0.1 μm: 3.0×10 6 particles / mm 2 or more, 2.5×10 7 particles / mm 2 or less) Among the precipitate particles in the aluminum alloy part, when the number density B of the precipitate particles having an equivalent circle diameter of less than 0.1 μm is 2.5×10 7 particles / mm 2 or less, the coarsening of the recrystallized grains can be suppressed, and the elongation and formability can be further improved. Therefore, the number density B of the precipitate particles having an equivalent circle diameter of less than 0.1 μm is preferably 2.5×10 7 particles / mm 2 or less, more preferably 2.3×107 pieces / mm 2 It is more preferably below, 2.0×10 7 pieces / mm 2 It is even more preferably below. On the other hand, when the number density B of precipitate particles having an equivalent circle diameter of less than 0.1 μm is 3.0×10 6 pieces / mm 2 or more, the strength can be further improved. Therefore, the number density B of precipitate particles having an equivalent circle diameter of less than 0.1 μm is 3.0×10 6 pieces / mm 2 or more, preferably 6.0×10 6 pieces / mm 2 or more, more preferably 1.0×10 7 pieces / mm 2 It is even more preferably below.

[0033] <Manufacturing method of aluminum alloy part> The manufacturing method of the aluminum alloy part in this embodiment will be specifically described below.

[0034] The manufacturing method of the aluminum alloy part in this embodiment includes, for example, a step of casting an aluminum alloy having the above chemical composition, a step of homogenization treatment, a step of hot rolling, a step of cold rolling, and a step of annealing.

[0035] Furthermore, each step will be described in detail. [Melting, casting] An ingot of a predetermined shape is produced from a molten metal obtained by melting an aluminum alloy having the above chemical composition. The method of melting and casting the aluminum alloy is not particularly limited, and a conventional method or a known method may be used.

[0036] [Homogenization heat treatment] Next, the cast aluminum alloy ingot is subjected to homogenization heat treatment. The conditions for the homogenization heat treatment are set such that the ratio of the number density of precipitates of 0.1 μm or more that serve as recrystallization nuclei and the number density of precipitates of less than 0.1 μm that suppress recrystallization but improve strength is within an appropriate range. For example, it is preferably 450°C to 620°C, more preferably 470°C to 600°C, and even more preferably 480°C to 580°C.

[0037] [Hot rolling] Hot rolling is performed on the aluminum alloy material after the homogenization heat treatment. The starting temperature and the finishing temperature of the hot rolling are set such that the ratio of the number density of precipitates of 0.1 μm or more that serve as recrystallization nuclei and the number density of precipitates of less than 0.1 μm that suppress recrystallization but improve strength is within an appropriate range. For example, the starting temperature is preferably 440°C to 610°C, and the finishing temperature is preferably 230°C to 400°C. More preferably, the starting temperature is 470°C to 570°C, and the finishing temperature is 250°C to 370°C.

[0038] [Cold rolling] Cold rolling is performed on the aluminum alloy material after the hot rolling. The strain applied during cold rolling is set to an appropriate range of rolling reduction in order to promote recrystallization during the final annealing. For example, it is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more.

[0039] [Final annealing] Final annealing treatment is performed on the aluminum alloy sheet that has been subjected to the above cold rolling. If the temperature of the final annealing treatment at this time is less than 280°C, recrystallization will not occur sufficiently, resulting in a decrease in elongation. Therefore, the final annealing temperature is preferably 280°C or higher, more preferably 290°C or higher, and even more preferably 300°C or higher. On the other hand, when the final annealing temperature is 330°C or lower, the ratio of the number density of precipitate particles of 0.1 μm or more and the number density of precipitate particles of less than 0.1 μm can be easily adjusted to the desired range, and the elongation can be improved. Therefore, the final annealing temperature is preferably 330°C or lower, more preferably 320°C or lower. The holding time at the final annealing temperature is not particularly limited and can be, for example, 1 hour or more and 5 hours or less. Also, the cooling rate after the final annealing is not particularly limited. Further, the final annealing treatment may be performed in a batch annealing furnace or a continuous annealing furnace, but it is preferable to use a continuous annealing furnace.

[0040] Note that the aluminum alloy part in this embodiment can be manufactured from various aluminum alloy scraps with a high recycling rate, and the content of each component and the ratio of the number density of precipitate particles are adjusted so as to obtain excellent mechanical properties. The recycling rate is a value expressed as a percentage of the mass of the used aluminum alloy scraps with respect to the total mass of the obtained aluminum alloy part. If the recycling rate is 50% or more, an aluminum alloy part can be obtained using a sufficient amount of aluminum alloy scraps, and sufficient reduction of the manufacturing cost and CO 2 emission can be achieved. Therefore, a high recycling rate is preferably 50% or more, more preferably 60% or more, still more preferably 75% or more, and particularly preferably 90% or more.

[0041] The aluminum alloy rolled product according to this embodiment may have a part thereof constituted by an aluminum alloy part, or all of the aluminum alloy rolled product may be constituted by an aluminum alloy part. An example in which a part of the aluminum alloy rolled product is constituted by an aluminum alloy part will be described.

[0042] The aluminum alloy rolled product according to this embodiment may be composed of a clad material having a core material and a skin material laminated on at least a part of the surface of the core material. Examples of the skin material include sacrificial anode materials. Hereinafter, the components contained in the sacrificial anode material, which is an example of the core material and the skin material contained in the aluminum alloy rolled product, and the reasons for limiting their contents will be described below.

[0043] <Core material> The core material is made of the above aluminum alloy part. Therefore, the reasons for limiting each component contained in the core material and its content are as described in the explanation of the above aluminum alloy part.

[0044] <Sacrificial anode material> (Zn: 0.50 mass% or more and 6.00 mass% or less) Zn in the sacrificial anode material is an element that has the effect of lowering the potential of the base material and enhancing the sacrificial corrosion prevention effect against the core material, thereby preventing pitting corrosion and crevice corrosion. If the Zn content in the sacrificial anode material is 0.50 mass% or more, a sufficient sacrificial corrosion prevention effect can be obtained. Therefore, the Zn content in the sacrificial anode material is preferably 0.50 mass% or more, more preferably 0.60 mass% or more, and even more preferably 0.70 mass% or more based on the total mass of the sacrificial anode material. Also, when the Zn content in the sacrificial anode material is 6.00 mass% or less, it is possible to prevent the self-corrosion property of the sacrificial anode material from increasing too much and suppress the decrease in the corrosion resistance of the aluminum alloy drawn material. Therefore, the Zn content in the sacrificial anode material is preferably 6.00 mass% or less, more preferably 5.70 mass% or less, and even more preferably 5.50 mass% or less based on the total mass of the sacrificial anode material.

[0045] (Si: 0.05 mass% or more and 1.50 mass% or less) Si in the sacrificial anode material is an element that has the effect of improving the strength of the sacrificial anode material. If the Si content in the sacrificial anode material is 0.05 mass% or more, the effect of improving the strength can be obtained. Therefore, the Si content in the sacrificial anode material is preferably 0.05 mass% or more, more preferably 0.10 mass% or more, and even more preferably 0.15 mass% or more based on the total mass of the sacrificial anode material. Also, when the Si content in the sacrificial anode material is 1.50 mass% or less, it is possible to prevent the formation of large Si compounds and Si grains and suppress the decrease in formability. Therefore, the Si content in the sacrificial anode material is preferably 1.50 mass% or less, more preferably 1.45 mass% or less, and even more preferably 1.40 mass% or less based on the total mass of the sacrificial anode material.

[0046] (Fe: 0.05 mass% or more and 2.00 mass% or less) Fe in the sacrificial anode material forms an Al-Fe-Mn-Si-based compound together with Si and Mn, and is an element having an effect of improving strength by dispersion strengthening. If the Fe content in the sacrificial anode material is 0.05 mass% or more, the effect of improving strength can be obtained. Therefore, the Fe content in the sacrificial anode material is preferably 0.05 mass% or more, more preferably 0.10 mass% or more, and even more preferably 0.12 mass% or more with respect to the total mass of the sacrificial anode material. Further, when the Fe content in the sacrificial anode material is 2.00 mass% or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Fe content in the sacrificial anode material is preferably 2.00 mass% or less, more preferably 1.80 mass% or less, and even more preferably 1.60 mass% or less with respect to the total mass of the sacrificial anode material.

[0047] (Mg: 3.00 mass% or less) Mg in the sacrificial anode material is an element that improves the strength of the sacrificial anode material itself by precipitating Mg 2 Si. However, in the present embodiment, the Mg content in the sacrificial anode material may be 0 mass%. Further, when the Mg content in the sacrificial anode material is 3.00 mass% or less, it can be easily crimped during hot clad rolling. Therefore, the Mg content in the sacrificial anode material is preferably 3.00 mass% or less, more preferably 2.80 mass% or less, and even more preferably 2.60 mass% or less with respect to the total mass of the sacrificial anode material.

[0048] (Mn: 1.80 mass% or less) Mn in the sacrificial anode material is an element that has the effect of improving strength by dissolving in the base material or forming an Al-Mn-Si-based intermetallic compound together with Si. However, in the present embodiment, the Mn content in the sacrificial anode material may be 0% by mass. Further, when the Mn content in the sacrificial anode material is 1.80% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in formability can be suppressed. Therefore, the Mn content in the sacrificial anode material is preferably 1.80% by mass or less, more preferably 1.60% by mass or less, and even more preferably 1.40% by mass or less with respect to the total mass of the sacrificial anode material.

[0049] (Cu: 0.50% by mass or less) When the Cu content in the sacrificial anode material is 0.50% by mass or less, the pitting potential of the sacrificial anode material can be prevented from nobilizing, and the effect of sacrificial corrosion can be sufficiently obtained. Therefore, the Cu content in the sacrificial anode material is preferably 0.50% by mass or less, more preferably 0.40% by mass or less, and even more preferably 0.30% by mass or less with respect to the total mass of the sacrificial anode material.

[0050] (Cr: 0.30% by mass or less) Cr in the sacrificial anode material is an element that has the effect of improving strength by solid solution strengthening. However, in the present embodiment, the Cr content in the sacrificial anode material may be 0% by mass. Further, when the Cr content in the sacrificial anode material is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Cr content in the sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less with respect to the total mass of the sacrificial anode material.

[0051] (Ti: 0.30% by mass or less) Ti in the sacrificial anode material is an element having the effect of improving strength by solid solution strengthening. However, in this embodiment, the Ti content in the sacrificial anode material may be 0% by mass. Also, when the Ti content in the sacrificial anode material is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in workability can be suppressed. Therefore, the Ti content in the sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less with respect to the total mass of the sacrificial anode material.

[0052] (Zr: 0.30% by mass or less) Zr in the sacrificial anode material is an element having the effect of improving strength by solid solution strengthening. However, in this embodiment, the Zr content in the sacrificial anode material may be 0% by mass. Also, when the Zr content in the sacrificial anode material is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in workability can be suppressed. Therefore, the Zr content in the sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less with respect to the total mass of the sacrificial anode material.

[0053] (V: 0.30% by mass or less) V in the sacrificial anode material is an element having the effect of improving strength by solid solution strengthening. However, in this embodiment, the V content in the sacrificial anode material may be 0% by mass. Also, when the V content in the sacrificial anode material is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in workability can be suppressed. Therefore, the V content in the sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less with respect to the total mass of the sacrificial anode material.

[0054] (Balance: Al and inevitable impurities) The remainder of the sacrificial anode material contained in the aluminum alloy rolled product is Al and inevitable impurities. The inevitable impurities include Ca, Be, Sb, rare earth elements, Li, etc. Specifically, they may be contained in the range of Ca: 0.05% by mass or less, Be: 0.01% by mass or less, and other elements: less than 0.01% by mass. Also, the total amount of inevitable impurities in the sacrificial anode material is preferably 0.05% by mass or less based on the total mass of the sacrificial anode material.

[0055] <Form of the aluminum alloy rolled product> In this embodiment, the form of the aluminum alloy rolled product is not particularly limited. As described above, it may be a plate-shaped aluminum alloy rolled product consisting only of the aluminum alloy part, or it may be in a form in which a plate-shaped core material and a plate-shaped skin material are laminated. When laminated, the skin material may be laminated only on a part of the surface of the core material, or may be laminated on the entire surface of one or both surfaces. Also, it may be a clad material obtained by extrusion. For example, the skin material may be laminated on at least one of the inner and outer surfaces of a hollow extruded material, or on the outer surface of a solid extruded material.

Examples

[0056] Examples are given below to more specifically explain this embodiment. However, the present invention is not limited to these examples, and modifications can be made and implemented within the range that conforms to the gist of the present invention, and all of them are included in the technical scope of the present invention.

[0057] <Manufacture of the aluminum alloy rolled product> The aluminum alloy raw material was melted at a temperature of 730°C. Then, by casting this at a temperature of 700°C, an ingot for the core material with a thickness of 50 mm, a width of 145 mm, and a length of 250 mm was produced. Also, an ingot for the sacrificial anode material containing 0.15% by mass of Si, 0.25% by mass of Fe, and 1.0% by mass of Zn was manufactured.

[0058] Next, the obtained ingots for the core material and the sacrificial anode material were subjected to a homogenization treatment at an appropriate temperature in the range of 480°C to 540°C for 4 hours to obtain a homogenized material for the core material and a homogenized material for the sacrificial anode material. The appropriate soaking temperature varies depending on the components. In this embodiment, the soaking temperature was set to a temperature 70°C to 150°C lower than the solidus temperature. Then, the homogenized material for the sacrificial anode material was rolled and laminated on one surface of the homogenized material for the core material to produce a clad material for rolling. At that time, it was laminated by calculating so that the clad ratio of the sacrificial anode material would be 17%. In the hot rolling process, the clad material for rolling with a thickness of 50 mm, a width of 145 mm, and a length of 100 mm was hot-rolled until the thickness became 2.5 mm and the length became about 1.8 m. The starting temperature of the hot rolling was set to an appropriate temperature in the range of 470°C to 530°C. The appropriate starting temperature of the hot rolling varies depending on the components and was set to a temperature 80°C to 160°C lower than the solidus temperature. Also, the finishing temperature of the hot rolling was set to an appropriate temperature in the range of 280°C to 320°C. The appropriate finishing temperature of the hot rolling varies depending on the components and was set to a temperature 0°C to 30°C higher than the recrystallization temperature.

[0059] After that, cold rolling was performed on the aluminum alloy plate subjected to hot rolling. In the cold rolling process, the aluminum alloy plate after hot rolling with a thickness of 2.5 mm and a length of about 1.8 m was cold-rolled until the thickness became 0.15 mm. Then, the aluminum alloy plate subjected to cold rolling was subjected to a final annealing treatment in a continuous annealing furnace. The temperature of this final annealing treatment was set to an appropriate temperature in the range of 300°C to 320°C and held for 1 hour to 5 hours. The appropriate final annealing temperature varies depending on the components and was set to a temperature 10°C to 30°C higher than the recrystallization temperature. As a result, a rolled material (aluminum alloy extended material) of the above size in which a core material made of an aluminum alloy part and a sacrificial anode material are laminated was obtained.

[0060] The contents of the respective components in the obtained aluminum alloy extended material, the values obtained by the formula, the number density of the precipitate particles, the ratio of the number density of the precipitate particles, and the evaluation results of the tensile strength and elongation are shown in Tables 1 and 2 below. Note that the balance of the respective components of the aluminum alloy extended material shown in Table 1 is Al and unavoidable impurities.

[0061] <Evaluation of Aluminum Alloy Extruded Material> (Evaluation of Mechanical Properties) In accordance with the "Tensile Test Method for Metallic Materials" of JIS Z 2241:2023, No. 13B test pieces described in Appendix B were taken from the obtained aluminum alloy extruded material, and a tensile test was carried out in the range of 10 to 35 °C, and the tensile strength and elongation after fracture were measured. As the evaluation criteria, those with a tensile strength of 120 MPa or more and an elongation of 14% or more were judged to have good mechanical properties. Since a high formability can be obtained when the aluminum alloy extruded material has excellent elongation, specifically, when the elongation is 14% or more, it can be judged that the formability is particularly excellent.

[0062] In this example, a multi-layer rolled material in which a core material made of an aluminum alloy part and a sacrificial anode material are laminated is produced, and the mechanical properties are judged according to the above evaluation criteria. However, even a single plate made only of the aluminum alloy part can be judged according to the above criteria. This is because, in terms of strength, the single plate tends to be improved compared to the multi-layer rolled material. Also, although the elongation of the single plate tends to be lower than that of the multi-layer rolled material, since the thickness of the sacrificial anode material is extremely thin at 30 μm or less compared to the thickness of the multi-layer rolled material, it is considered that the elongation will not decrease even for a single plate.

[0063] (Measurement of Precipitate Number Density) The number density of precipitate particles with an equivalent circle diameter of 0.1 μm or more and the number density of precipitate particles with an equivalent circle diameter of less than 0.1 μm are obtained by calculating the number per unit area of precipitates in 20 fields of view using a scanning electron microscope with a magnification of 1000 times. In this embodiment, the total area of 0.21 mm 2 is measured in 20 fields of view. Then, the number density can be calculated by actually dividing the total number of the above compounds in 20 fields of view by 0.21 mm 2 of the area.

[0064]

Table 1

[0065]

Table 2

[0066] <Evaluation Results of Aluminum Alloy Elongated Materials> As shown in Table 1 above, in Invention Examples 1 to 13, the content of components contained in the aluminum alloy elongated material (aluminum alloy part), the value calculated by the formula, and the ratio of the number density of precipitate particles were within the ranges defined in the present invention, and the mechanical properties were good.

[0067] On the other hand, as shown in Table 2 above, in Comparative Examples 1 and 2, the ratio A / B of the number density of precipitate particles was smaller than the range defined in the present invention. Therefore, the elongation became smaller.

[0068] In Comparative Examples 3 and 4, the value α calculated from Formula (1) and the ratio A / B of the number density of precipitate particles were smaller than the ranges defined in the present invention. Therefore, the elongation became smaller.

[0069] In Comparative Example 5, since the Si content was less than the lower limit defined in the present invention, the elongation became smaller.

[0070] In Comparative Example 6, since the Si content, the value α calculated from Formula (1), and the ratio A / B of the number density of precipitate particles were less than the lower limits defined in the present invention, the elongation became smaller.

[0071] In Comparative Examples 7 and 8, since the value β calculated from Formula (2) and the ratio A / B of the number density of precipitate particles exceeded the upper limits defined in the present invention, the elongation became smaller.

[0072] Comparative Example 9 is an example using 100% of the material scraps for automotive heat exchangers. Since the Mn content exceeded the upper limit defined in the present invention and the ratio A / B of the number density of precipitate particles was less than the lower limit defined in the present invention, the elongation became smaller.

[0073] Comparative Example 10 is an example using 100% of used beverage cans (UBC). The Si content and the value α calculated by formula (1) were less than the lower limit defined in the present invention. Therefore, due to solid solution strengthening and precipitation strengthening, the tensile strength became larger and the elongation became smaller compared with the inventive examples.

[0074] Comparative Example 11 is an example using 100% of sash scraps. The Si content, Mn content, and the value α calculated from formula (1) were less than the lower limit defined in the present invention. Therefore, the tensile strength became smaller.

[0075] Comparative Example 12 is an example using 100% of alloy symbol AC4C material defined in JIS H 5202:2010. The Mn content was less than the lower limit defined in the present invention, and the value β calculated by formula (2) exceeded the upper limit defined in the present invention. Therefore, the tensile strength decreased.

[0076] In Comparative Example 13, the Fe content and the ratio A / B of the number density of precipitate particles were less than the lower limit defined in the present invention. Therefore, the elongation became smaller.

[0077] Also, in Comparative Example 14, the Fe content and Mn content, and in Comparative Example 15, the Cu content exceeded the upper limit defined in the present invention, so the elongation became smaller.

[0078] In Comparative Example 16, the Mn content and the ratio A / B of the number density of precipitate particles exceeded the upper limit defined in the present invention, so the elongation became smaller.

[0079] In Comparative Example 17, the Zn content exceeded the upper limit defined in the present invention, so the elongation became smaller.

[0080] As shown by these results, in the aluminum alloy rolled material according to the present invention, the aluminum alloy part can be blended with various types of aluminum scraps at a high recycling rate, and the content of each component, the values α and β calculated from specific components, and the ratio A / B of the number density of precipitate particles are appropriately controlled. Therefore, even in a rolled material of a single plate composed only of the aluminum alloy part or a rolled material in which the aluminum alloy part and the skin material are laminated, mechanical properties such as elongation and strength are excellent, and particularly excellent elongation enables high formability to be obtained.

Claims

1. An aluminum alloy wrought material having an aluminum alloy part, The aluminum alloy portion has, with respect to the total mass of the aluminum alloy portion, Si: 1.0% by mass or more and 7.5% by mass or less, Fe: 0.15% by mass or more and 0.8% by mass or less, and Mn: 0.3% by mass or more and 1.0% by mass or less; Cu: 0.5% by mass or less, Mg: 2.0% by mass or less, Zn: 0.7% by mass or less; The balance is Al and unavoidable impurities. When the content of the Si relative to the total mass of the aluminum alloy portion is [Si] in mass%, and the content of the Mg relative to the total mass of the aluminum alloy portion is [Mg] in mass%, The value α calculated by the following formula (1) is 0 or more, and the value β calculated by the following formula (2) is 7.5 or less, Formula (1): α=[Si]-2×[Mg] Formula (2): β=[Si]+2.25×[Mg] the aluminum alloy portion has precipitate particles, The number density of precipitate particles having a circle equivalent diameter of 0.1 μm or more among the precipitate particles is defined as A (particles / mm ２ , the number density of precipitate particles with a circle equivalent diameter of less than 0.1 μm is defined as B (particles / mm ２ ), the ratio A / B of number density A to number density B is 1.1×10 －３ That's it, 5.0 x 10 －３ 1. An aluminum alloy wrought material, characterized in that:

2. The number density A (pieces / mm ２ ) is 1.9 x 10 ４ That's it, 4.0 x 10 ４ 2. The aluminum alloy wrought product according to claim 1, wherein:

3. The number density B (pieces / mm ２ ) is 3.0 x 10 ６ That's it, 2.5 x 10 ７ 3. The aluminum alloy wrought material according to claim 1 or 2, wherein:

4. The ratio A / B of the number density A to the number density B is 1.2×10 －３ 2. The aluminum alloy wrought product according to claim 1, characterized in that

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