Rolled material made of aluminum alloy, cladding material, and brazing sheet

Abstract

To provide a rolled material.SOLUTION: A rolled material contains Cr by 0.05 mass% or more and 1.00 mass% or less, Fe by 0.05 mass% or more and 1.00 mass% or less, Si by 0.05 mass% or more and 1.50 mass% or less, the balance consisting of Al and inevitable impurities, mass% of Fe and Si satisfies the relation of 0.8Fe≤Si, an intermetallic compound containing Cr having a diameter of 0.01 μm or more and less than 5.00 μm in a circle equivalent diameter is 10 or more in an observation visual field per 10000 μm2 of a RD-TD parallel surface, and furthermore, an intermetallic compound having a diameter of 10 μm or more in a circle equivalent diameter is less than 3 in an observation visual field per 10000 μm2 of a RD-TD parallel surface.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to rolled materials, clad materials, and brazing sheets made of aluminum alloys.

Background Art

[0002] Aluminum is known as a metal with relatively good corrosion resistance. However, when exposed to a chloride environment, the oxide film is destroyed and corrosion occurs. In this case, the corrosion tends to progress in the thickness direction of the material, penetrating the material in a relatively short time and causing problems such as a decrease in material strength and leakage of the contents. Therefore, when using aluminum, it is necessary to perform some anti-corrosion treatment. Common anti-corrosion methods include surface treatment using a coating film with excellent environmental resistance, joining a sacrificial anode material, or laminating as a multi-layer material for sacrificial corrosion protection. Patent Documents 1 and 2 disclose clad materials composed of a brazing material, a sacrificial material, and a core material. Patent Document 3 discloses a surface treatment method for improving corrosion resistance by sealing an anodic oxide film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although the performance of the anti-corrosion method is excellent, the surface treatment is costly. In addition, if there are coating irregularities in the surface treatment, there is a risk of corrosion. There is also a risk of corrosion when the material is damaged by external factors during use in the market.

[0005] Therefore, an object of the present invention is to provide a rolled material, a clad material, and a brazing sheet made of a highly corrosion-resistant aluminum alloy.

Means for Solving the Problems

[0006] In the production of a rolled material made of an aluminum alloy added with Cr, Fe, and Si, the inventors have found that by controlling the production conditions to densely distribute a compound containing Cr, even when corrosion occurs on the alloy surface, the corroded portion is covered with a highly corrosion-resistant film containing Cr using the corrosion as a driving force, thereby suppressing the progress of corrosion.

[0007] The rolled material made of the aluminum alloy of the present invention contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance being Al and unavoidable impurities, Fe and Si satisfying the relationship of 0.8Fe ≦ Si, and the intermetallic compound containing Cr having a diameter of 0.01 μm or more and less than 5.00 μm in terms of equivalent circle diameter is 10 or more in the observation field of view per 10000 μm 2 in the RD-TD parallel plane, and further, the intermetallic compound having a diameter of 10 μm or more in terms of equivalent circle diameter is less than 3 in the observation field of view. RD is the rolling direction, and TD is the transverse direction perpendicular to RD and the thickness direction (normal direction). The RD-TD parallel plane is a plane formed by shaving the surface of the rolled material and parallel to RD and TD.

[0008] Cr: 0.05% by mass or more and 1.00% by mass or less By densely distributing the compound containing Cr, Cr is concentrated on the alloy surface layer when the compound is decomposed by slight corrosion, and a corrosion-resistant oxide film containing Cr is formed on the corroded portion, thereby improving the corrosion resistance of the alloy. When Cr is less than 0.05% by mass, a sufficient corrosion resistance effect (formation of a highly corrosion-resistant oxide film containing Cr) cannot be obtained, and when it exceeds 1.00% by mass, coarse intermetallic compounds are generated during casting, resulting in a decrease in rollability.

[0009] Fe: 0.05 mass% or more and 1.00 mass% or less Fe is distributed as intermetallic compounds such as Al-Fe-based and Al-Fe-Si-based. By devising the manufacturing conditions, the Fe sites can be doped with Cr, and the intermetallic compounds containing Cr can be densely distributed. If Fe is less than 0.05 mass%, the manufacturing cost will increase. If it exceeds 1.00 mass%, coarse intermetallic compounds will be generated during casting, resulting in a decrease in rollability.

[0010] Si: 0.05 mass% or more and 1.50 mass% or less When Si is contained together with Fe, the formation of Al-Fe-Si-based intermetallic compounds with a smaller cathodic reaction compared to Al-Fe-based intermetallic compounds is favored, and a highly corrosion-resistant oxide film containing Cr is formed against mild corrosion, improving the corrosion resistance of the alloy. If Si is less than 0.05 mass%, sufficient effect (formation of a highly corrosion-resistant oxide film containing Cr) cannot be obtained. If Si exceeds 1.50 mass%, the solidus temperature decreases, resulting in leakage during casting.

[0011] (Relationship between the contents of Fe and Si) Fe and Si have a relationship of 0.8Fe ≦ Si with respect to the mass% of the composition of the aluminum alloy (hereinafter referred to as the relational expression). By satisfying the above relational expression, the formation of Al-Fe-Si-based intermetallic compounds with a smaller cathodic reaction than Al-Fe-based intermetallic compounds can be favored, and a highly corrosion-resistant oxide film containing Cr can be formed against mild corrosion, improving the corrosion resistance of the alloy. If the relational expression cannot be satisfied, the formation of Al-Fe-based compounds becomes dominant, resulting in a decrease in corrosion resistance.

[0012] (Distribution of fine intermetallic compounds) In the observation field per 10000 μm of the RD-TD parallel plane, there are 10 or more intermetallic compounds containing Cr having a diameter equivalent to a circle of 0.01 μm or more and less than 5.00 μm. 2 ​The dense distribution of fine intermetallic compounds containing Cr causes Cr to concentrate on the alloy surface layer when the intermetallic compounds containing Cr are decomposed by slight corrosion, generating a corrosion-resistant oxide film containing Cr on the corroded part and improving the corrosion resistance of the alloy. The fine intermetallic compounds containing Cr are 10000 μm 2 If there are less than 10 in the observation field per 10000 μm

[0013] (Distribution of coarse intermetallic compounds) In the 10000 μm of the RD-TD parallel plane 2 in the observation field per 10000 μm, there are less than 3 intermetallic compounds having a diameter equivalent to a circle of 10 μm or more. When a large number of coarse intermetallic compounds having a diameter equivalent to a circle of 10 μm or more are distributed, they become the starting points of corrosion, and further inhibit the formation of the oxide film containing Cr, thus reducing the corrosion resistance of the alloy.

[0014] (Corrosion resistance after SWAAT test) The corroded part of the test material loaded for 24 hours in the SWAAT test (Sea Water Acidified Test: conforming to ASTM's G85-A) contains Cr in the film. The formation of a film containing Cr with slight corrosion as the driving force improves the corrosion resistance of the alloy.

[0015] The rolled material of the present invention preferably contains 0.05% by mass or more and 1.00% by mass or less of Ti. Ti can improve the corrosion resistance of the rolled material because it controls the corrosion form in a planar manner and reduces the corrosion rate by forming layers with different Ti concentrations in a layered manner by the peritectic reaction during casting and subsequent appropriate rolling processes. If Ti is less than 0.05% by mass, the improvement in corrosion resistance is low. If Ti exceeds 1.00% by mass, coarse intermetallic compounds are generated during casting and the rollability decreases. The rolled material of the present invention may further contain any one or a plurality of elements among Mn, Mg, Cu, Zn, Zr, V, Sr, Sc, Mo.

[0016] The rolled material of the present invention preferably contains 0.10% by mass or more and 2.00% by mass or less of Mn. Mn precipitates as intermetallic compounds such as Al-Mn-based, Al-Mn-Si-based, Al-Mn-Si-Fe-based, etc., and can improve the material strength of the rolled material. When Mn is less than 0.10% by mass, the effect of improving the material strength is low. When Mn exceeds 2.00% by mass, coarse intermetallic compounds are generated during casting, resulting in a decrease in rollability.

[0017] The rolled material of the present invention preferably contains 0.01% by mass or more and 3.00% by mass or less of Mg. Mg can precipitate as a solid solution or as intermetallic compounds such as Mg2Si, etc., and improve the material strength of the rolled material. When Mg is less than 0.01% by mass, the effect of improving the material strength is low. When Mg exceeds 3.00% by mass, the material strength of the rolled material is too high, making it difficult to manufacture the material (rolling).

[0018] The rolled material of the present invention preferably contains 0.01% by mass or more and 1.00% by mass or less of Cu. Cu can improve the material strength of the rolled material by solid solution. When Cu is less than 0.01% by mass, the effect of improving the material strength is low. When Cu exceeds 1.00% by mass, the material strength of the rolled material is too high, making it difficult to manufacture the material (rolling).

[0019] The rolled material of the present invention preferably contains 0.01% by mass or more and 8.00% by mass or less of Zn. Zn solidifies and makes the natural potential of the material of the rolled material lower than that of other members, achieving a sacrificial corrosion protection effect. When Zn is less than 0.01% by mass, the effect is insufficient. When Zn exceeds 8.00% by mass, the potential is excessively lowered and the corrosion rate increases.

[0020] The rolled material of the present invention preferably contains any one or a plurality of elements of Zr, V, Sr, Sc, Mo, each element in an amount of 0.01% by mass or more and 0.50% by mass or less. Zr, V, Sr, Sc, and Mo can form intermetallic compounds to improve the material strength of the rolled material. If Zr, V, Sr, Sc, and Mo are less than 0.05% by mass, the effect of improving the material strength is low. If Zr, V, Sr, Sc, and Mo exceed 0.50% by mass, coarse intermetallic compounds are generated during casting, resulting in a decrease in rollability.

[0021] The present invention relates to a clad material comprising a core material and a skin material joined to one or both sides of the core material, wherein the skin material is made of the rolled material. The skin material contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance consisting of Al and unavoidable impurities. Fe and Si satisfy the relationship of 0.8Fe ≤ Si. The number of intermetallic compounds containing Cr with an equivalent circle diameter of 0.01 μm or more and less than 5.00 μm is 10 or more per observation field of 10,000 μm2 in the RD-TD parallel plane, and the number of intermetallic compounds with an equivalent circle diameter of 10 μm or more is less than 3 in the observation field. The skin material may further contain any one or a plurality of elements among Mn, Mg, Cu, Zn, Zr, V, Sr, Sc, and Mo.

[0022] The present invention relates to a brazing sheet comprising a core material made of an aluminum alloy and a brazing material joined to one or both sides of the core material, wherein the core material is made of the rolled material. The core material contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance consisting of Al and unavoidable impurities. Fe and Si satisfy the relationship of 0.8Fe ≤ Si. The number of intermetallic compounds containing Cr with an equivalent circle diameter of 0.01 μm or more and less than 5.00 μm is 10 or more per observation field of 10,000 μm2 in the RD-TD parallel plane, and the number of intermetallic compounds with an equivalent circle diameter of 10 μm or more is less than 3 in the observation field. The core material may further contain any one or a plurality of elements among Mn, Mg, Cu, Zn, Zr, V, Sr, Sc, and Mo.

Advantages of the Invention

[0023] According to the present invention, intermetallic compounds containing Cr are densely distributed, and a highly corrosion-resistant film containing Cr is formed using slight corrosion as a driving force, so that the corrosion resistance can be maintained over a long period of time.

Mode for Carrying Out the Invention

[0024] The rolled material made of an aluminum alloy according to an embodiment of the present invention contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, and the balance consists of Al and unavoidable impurities.

[0025] Cr: 0.05% by mass or more and 1.00% by mass or less Cr densely distributes compounds containing Cr, so that when the compounds are decomposed by slight corrosion, Cr is concentrated on the alloy surface layer to form a corrosion-resistant oxide film containing Cr in the corroded part, thereby improving the corrosion resistance of the alloy. If Cr is less than 0.05% by mass, a sufficient corrosion resistance effect (formation of a highly corrosion-resistant oxide film containing Cr) cannot be obtained, and if it exceeds 1.00% by mass, coarse intermetallic compounds are generated during casting, resulting in a decrease in rollability.

[0026] Fe: 0.05% by mass or more and 1.00% by mass or less Fe is distributed as intermetallic compounds such as Al-Fe-based and Al-Fe-Si-based. By devising the manufacturing conditions, these compounds containing Fe can be doped with Cr at Fe sites, and intermetallic compounds containing Cr can be densely distributed. If Fe is less than 0.05% by mass, the manufacturing cost increases, and if it exceeds 1.00% by mass, coarse intermetallic compounds are generated during casting, resulting in a decrease in rollability.

[0027] Si: 0.05% by mass or more and 1.50% by mass or less When Si is contained together with Fe, the formation of Al-Fe-Si-based compounds with a smaller cathodic reaction compared to Al-Fe-based compounds is favored, and a Cr-containing oxide film is formed against mild corrosion, thereby improving the corrosion resistance of the alloy. If Si is less than 0.05% by mass, a sufficient effect (formation of a highly corrosion-resistant oxide film containing Cr) cannot be obtained. If Si exceeds 1.50% by mass, the solidus temperature decreases and bleeding occurs during casting.

[0028] (Relationship between the contents of Fe and Si) Fe and Si have a relationship of 0.8Fe ≤ Si with respect to the mass% of the composition of the aluminum alloy (hereinafter referred to as the relational expression). By satisfying the above relational expression, the formation of Al-Fe-Si-based compounds with a smaller cathodic reaction than Al-Fe-based compounds can be favored, and a Cr-containing oxide film can be formed against mild corrosion, thereby improving the corrosion resistance of the alloy. If the relational expression cannot be satisfied, the formation of Al-Fe-based compounds becomes dominant and the corrosion resistance decreases.

[0029] The rolled material made of an aluminum alloy according to an embodiment of the present invention may contain any one or a plurality of elements among Ti, Mn, Mg, Cu, Zn, Zr, V, Sr, Sc, and Mo.

[0030] Preferably, the rolled material contains Ti in an amount of 0.05% by mass or more and 1.00% by mass or less. Ti can improve the corrosion resistance of the rolled material because it controls the corrosion form in a planar manner by forming layers with different Ti concentrations in a layered manner by the peritectic reaction during casting and subsequent appropriate rolling processes, thereby reducing the corrosion rate. If Ti is less than 0.05% by mass, the improvement in corrosion resistance is low. If Ti exceeds 1.00% by mass, coarse intermetallic compounds are generated during casting and the rollability decreases.

[0031] Preferably, the rolled material contains Mn in an amount of 0.10% by mass or more and 2.00% by mass or less. Mn precipitates as intermetallic compounds such as Al-Mn-based, Al-Mn-Si-based, and Al-Mn-Si-Fe-based, and can improve the material strength of the rolled material. If the Mn content is less than 0.10% by mass, the effect of improving the material strength is low. If the Mn content exceeds 2.00% by mass, coarse intermetallic compounds are formed during casting, resulting in a decrease in rollability.

[0032] Preferably, the rolled material contains 0.01% to 3.00% by mass of Mg. Mg can be dissolved or precipitated as intermetallic compounds such as Mg2Si to improve the material strength of the rolled material. If the Mg content is less than 0.01% by mass, the effect of improving the material strength is low. If the Mg content exceeds 3.00% by mass, the material strength of the rolled material is too high, making it difficult to manufacture the material (rolling).

[0033] Preferably, the rolled material contains 0.01% to 1.00% by mass of Cu. Cu can improve the material strength of the rolled material by solid solution. If the Cu content is less than 0.01% by mass, the effect of improving the material strength is low. If the Cu content exceeds 1.00% by mass, the material strength of the rolled material is too high, making it difficult to manufacture the material (rolling).

[0034] Preferably, the rolled material contains 0.01% to 8.00% by mass of Zn. Zn is dissolved to make the natural potential of the material of the rolled material lower than that of other members, achieving a sacrificial corrosion prevention effect. If the Zn content is less than 0.01% by mass, the effect is insufficient. If the Zn content exceeds 8.00% by mass, the potential is excessively lowered and the corrosion rate increases.

[0035] Preferably, the rolled material contains any one or a plurality of elements of Zr, V, Sr, Sc, and Mo, each element in an amount of 0.01% to 0.50% by mass. Zr, V, Sr, Sc, and Mo can form intermetallic compounds to improve the material strength of the rolled material. If the content of Zr, V, Sr, Sc, and Mo is less than 0.05% by mass, the effect of improving the material strength is low. If the content of Zr, V, Sr, Sc, and Mo exceeds 0.50% by mass, coarse intermetallic compounds are formed during casting, resulting in a decrease in rollability.

[0036] (Distribution of fine intermetallic compounds) In the observation field per 10,000 μm of the RD-TD parallel plane, there are 10 or more intermetallic compounds containing Cr with an equivalent circle diameter of 0.01 μm or more and less than 5.00 μm. The RD-TD parallel plane is formed by shaving the surface of the rolled material and is a plane parallel to RD and TD. 2 When the fine intermetallic compounds containing Cr are densely distributed, when the intermetallic compounds containing Cr are decomposed by slight corrosion, Cr is concentrated on the alloy surface layer to generate a corrosion-resistant oxide film containing Cr in the corroded part, and the corrosion resistance of the alloy can be improved. The fine intermetallic compounds containing Cr are 10,000 μm If there are less than 10 per observation field per 10,000 μm, an oxide film containing Cr cannot be generated. 2 If there are less than 10 per observation field per 10,000 μm, an oxide film containing Cr cannot be generated.

[0037] (Distribution of coarse intermetallic compounds) In the observation field per 10,000 μm of the RD-TD parallel plane 2 In the observation field per 10,000 μm, there are less than 3 intermetallic compounds with an equivalent circle diameter of 10 μm or more. If a large number of coarse intermetallic compounds with an equivalent circle diameter of 10 μm or more are distributed, they will become the starting points of corrosion, and further inhibit the formation of an oxide film containing Cr, so the corrosion resistance of the alloy will decrease.

[0038] (Corrosion of the rolled material) In the rolled material, the intermetallic compounds containing Cr are densely distributed, and a film containing Cr is generated using slight corrosion as the driving force. This oxide film containing Cr has high corrosion resistance. The condition for confirming the oxide film is to conduct a SWAAT test (Sea Water Acidified Test: conforming to ASTM's G85-A) on a test specimen made of the aluminum alloy with the above composition for 24 hours. In the test specimen that has undergone the SWAAT test, a corroded part is generated, and surface analysis in the thickness direction is performed on this corroded part by X-ray photoelectron spectroscopy (hereinafter referred to as XPS). This XPS measurement is carried out every 1.2 nm in depth with the sputtering time converted to SiO2 equivalent as the depth. The oxide film is defined as the range from the surface layer until the concentrations (intensities) of O and Al are reversed in the depth direction (O > Al on the surface layer side), and the presence or absence of Cr is confirmed at any measurement point in the oxide film. When Cr is present, a peak appears near 574 eV.

[0039] (Manufacturing method) The manufacturing method of the aluminum alloy sheet material includes an ingot manufacturing process for manufacturing an ingot, a homogenization process for homogenizing the ingot, a facing process for facing the ingot, a soaking heat treatment process for subjecting the faced ingot to soaking heat treatment, and a rolling process (hot rolling process and cold rolling process) for rolling the faced ingot.

[0040] (Ingot manufacturing process) The ingot manufacturing process manufactures an ingot (slab) by melt casting. The ingot is made of an aluminum alloy containing 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance being Al and inevitable impurities. This aluminum alloy may contain any one or more of Ti, Mn, Mg, Cu, Zn, Zr, V, Sr, Sc, and Mo. The aluminum alloy preferably contains 0.05% by mass or more and 1.00% by mass or less of Ti. The aluminum alloy preferably contains 0.10% by mass or more and 2.00% by mass or less of Mn. The aluminum alloy preferably contains 0.01% by mass or more and 3.00% by mass or less of Mg. The aluminum alloy preferably contains 0.01% by mass or more and 1.00% by mass or less of Cu. The aluminum alloy preferably contains 0.01% by mass or more and 8.00% by mass or less of Zn. The aluminum alloy preferably contains any one or more of the elements Zr, V, Sr, Sc, and Mo, each element being 0.01% by mass or more and 0.50% by mass or less. The casting temperature is 700 °C or more and less than 790 °C, preferably 730 °C or more and less than 770 °C. If the casting temperature during casting is less than 700 °C, the time staying in the crystallization temperature range during casting becomes long, and coarse intermetallic compounds that cannot be sufficiently crushed in the rolling process are generated. If the casting temperature during casting is 790 °C or more, it becomes impossible to manufacture due to molten metal leakage. The cooling rate is 0.1 °C / s or more, preferably 1 °C / s or more. If the cooling rate during casting is less than 0.1 °C / s, the time staying in the crystallization temperature range during casting becomes long, and coarse intermetallic compounds that cannot be sufficiently crushed in the rolling process are generated.

[0041] (Homogenization process) In the homogenization process, the state of heating the ingot to 400 °C or more and less than 600 °C, preferably the state of heating to 430 °C or more and less than 580 °C, is maintained. The holding time is 1 hour or more and 12 hours or less, preferably 3 hours or more and 10 hours or less. By performing heat treatment of the ingot at a predetermined temperature, Al-Fe-based and Al-Fe-Si-based intermetallic compounds are precipitated, and further Cr doping into Fe sites is promoted. If the temperature is less than 400 °C, a sufficient effect (homogenization) cannot be obtained. If the temperature is 600 °C or higher, the precipitates coarsen or redissolve, resulting in a sparse distribution.

[0042] (Surface machining) The upper and lower surfaces of the ingot are machined to remove the segregated portions and the oxide film.

[0043] (Soaking heat treatment) In the soaking heat treatment, the machined ingot is heated before processing. The heating temperature is maintained in a state of being heated to 450 °C or higher and less than 550 °C. The holding time is 1 hour or more and 12 hours or less, preferably 1 hour or more and 10 hours or less. The heating temperature and holding time of the soaking heat treatment are examples and are not limiting.

[0044] (Rolling process) In the hot rolling process, the machined ingot is rolled. The temperature in this hot rolling is 400 °C or higher and 500 °C or lower, and the rolling time is 5 minutes or more, preferably 10 minutes or more. By maintaining a state of applying dynamic strain at a high temperature for a predetermined time, the diffusion rate of Cr is improved due to grain boundaries and dislocations, promoting the doping of Cr into the Fe sites in the Al-Fe-based and Al-Fe-Si-based intermetallic compounds. If the rolling time is less than 5 minutes, the doping of Cr into the Fe sites in the intermetallic compounds becomes insufficient.

[0045] (Equivalent strain in hot rolling) In the hot rolling process, the equivalent strain ε in hot rolling shown in the following formula (1) is required to exceed 5.0 (ε > 5.0). ε = (2 / √3)ln(t0 / t) Formula (1) Here, t0 is the thickness of the slab (machined ingot) before the hot rolling process, and t is the thickness of the finished thick plate after passing through the hot rolling process. By controlling the hot rolling so as to satisfy the above condition (ε > 5.0), the coarse intermetallic compounds generated during casting can be crushed.

[0046] The cold rolling process rolls the thick plate that has undergone the hot rolling process. In cold rolling, the reduction ratio per pass is such that the reduction ratio per pass at a sheet thickness of 0.5 mm or more is 25% or more. By having a reduction ratio of 25% or more, intermetallic compounds containing Cr can be pulverized and densely dispersed.

[0047] Through the cold rolling process, a rolled material made of the aluminum alloy with the above composition is completed. The method for manufacturing an aluminum alloy sheet material performs solution treatment, intermediate annealing, and final annealing as required.

[0048] In the method for manufacturing a rolled material according to an embodiment of the present invention, by using an aluminum alloy in which the content ratio of Fe and Si is adjusted and added together with Cr as a raw material and controlling the manufacturing conditions of casting, homogenization treatment, and rolling, a compound with a small cathodic reaction can be preferentially generated, and coarse crystallized products can be suppressed. Thereby, it is possible to prevent a coarse intermetallic compound from becoming a starting point of corrosion and to prevent the formation of a Cr-containing film from being inhibited.

[0049] In the rolled material according to an embodiment of the present invention, due to the dense distribution of fine intermetallic compounds containing Cr, when the fine intermetallic compounds containing Cr are decomposed by fine corrosion, an oxide film having high corrosion resistance containing the decomposed Cr is formed. Thereby, it is possible to use the rolled material for a long period even if it is a single layer. Forming the surface of a conventional aluminum alloy as an anodic oxide film results in high costs. Also, if there are coating irregularities in the surface treatment, there is a risk of corrosion. There is a risk of corrosion when the surface is damaged by external factors during use in the market. Furthermore, when using a sacrificial anode material, corrosion of the sacrificial anode material will inevitably occur for sacrificial corrosion. If the corrosion products clog the flow path of the device or adhere to the surface of the device material, it may reduce the performance of the device and also damage the appearance of the device. In the case of applications such as air conditioner indoor units, since the corrosion products are scattered, it is not desirable. On the other hand, according to the rolled material according to the embodiment of the present invention, by forming an oxide film containing Cr using corrosion as a driving force, the generation of corrosion products can be suppressed, clogging of the flow path can be prevented, and the function and appearance of the material surface can be maintained well. In addition, the conventionally surface-treated plate materials and multi-layer materials will reduce the recyclability from the perspective of realizing a carbon-neutral society that has attracted attention in recent years. Without using such conventional corrosion prevention methods, the rolled material according to the embodiment of the present invention can be used as a single layer.

[0050] The rolled material according to the embodiment of the present invention can be used as the skin material of the clad material, and for example, it can be directly or through an intermediate layer bonded to one side or both sides of a core material made of a 3000 series aluminum alloy. The rolled material can be used as the core material of the brazing sheet. For example, a brazing material made of a 3000 series aluminum alloy is directly or through an intermediate layer bonded to one side or both sides of the core material.

Examples

[0051] The corrosion resistance of an aluminum alloy rolled material (sheet thickness 1 mm, temper O) formed by changing the materials and manufacturing conditions was evaluated.

[0052] (Materials) As the materials used for manufacturing, those containing Cr, Fe, Si with the balance being Al and inevitable impurities and those containing Cr, Fe, Si, Ti with the balance being Al and inevitable impurities were used. The mass % of Cr, Fe, Si, Ti in each sample is as shown in Table 1. Materials 1 to 9 contain 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance being Al and inevitable impurities, and the contents of Fe and Si (% by mass) satisfy the relationship of 0.8Fe ≤ Si. Materials 10 to 12 contain 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, 0.05% by mass or more and 1.50% by mass or less of Si, and 0.05% by mass or more and 1.00% by mass or less of Ti, with the balance being Al and inevitable impurities, and the contents of Fe and Si satisfy the relationship of 0.8Fe ≤ Si. Hereinafter, the ranges of 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, 0.05% by mass or more and 1.50% by mass or less of Si, and 0.05% by mass or more and 1.00% by mass or less of Ti may all be referred to as the first composition ranges. For Materials 42 to 47, the content of any one of Cr, Fe, and Si is not controlled within the first composition range. Among these, for Sample 46, the contents of Fe and Si do not satisfy the relationship of 0.8Fe ≤ Si. For Samples 49 and 50, the content of Ti exceeds the upper limit value. For Material 48, the contents of Cr, Fe, and Si are controlled within the first composition range, but the contents of Fe and Si do not satisfy the relationship of 0.8F ≤ Si.

[0053]

Table 1

[0054] (Manufacturing method) The manufacturing method of the aluminum alloy sheet material includes an ingot manufacturing process for manufacturing an ingot, a homogenization process for homogenizing the ingot, a facing process for facing the ingot, a soaking heat treatment process for subjecting the faced ingot to a soaking heat treatment, and a rolling process (hot rolling process and cold rolling process) for rolling the faced ingot.

[0055] (Ingot manufacturing process) The ingot manufacturing process manufactures an ingot (slab) by melting and casting. The casting temperature is 700°C or higher and less than 790°C. The cooling rate is 0.1°C / s or higher.

[0056] (Homogenization process) In the homogenization process, the ingot is maintained in a state of being heated to 400°C or higher and less than 600°C. The holding time is 5 hours.

[0057] (Surface machining) The upper and lower surfaces of the ingot are surface-machined to remove the segregated parts and the oxide film.

[0058] (Soaking heat treatment) In the soaking heat treatment, the surface-machined ingot is heated before processing.

[0059] (Rolling process) In the hot rolling process, the surface-machined ingot is rolled. The temperature in this hot rolling is 400°C or higher and 500°C or lower, and the rolling time is 5 minutes or longer.

[0060] (Equivalent strain in hot rolling) In the hot rolling process, it is a condition that the equivalent strain ε in hot rolling shown in the above formula (1) exceeds 5.0 (ε>5.0).

[0061] In the cold rolling process, the thick plate that has undergone the hot rolling process is rolled. The reduction ratio per pass in cold rolling is such that the reduction ratio per pass when the plate thickness is 0.5 mm or more is 25% or more. Then, by performing the final annealing at 360°C for 3 hours, the rolled material is made into an O-quality with a plate thickness of 1 mm.

[0062] The casting pouring temperature, casting cooling rate, homogenization treatment temperature, hot rolling time at 400°C or higher and 500°C or lower, equivalent strain in hot rolling, and reduction ratio per cold rolling pass of each manufacturing method are shown in Table 2. Note that for manufacturing methods A to F, the casting pouring temperature, casting cooling rate, homogenization treatment temperature, hot rolling time at 400°C or higher and 500°C or lower, equivalent strain in hot rolling, and reduction ratio per cold rolling pass are controlled within the above ranges, while for manufacturing methods G to M, the casting pouring temperature, casting cooling rate, homogenization treatment temperature, hot rolling time at 400°C or higher and 500°C or lower, equivalent strain in hot rolling, and reduction ratio per cold rolling pass are outside the above ranges.

[0063]

Table 2

[0064] Rolled materials were prepared using materials (any of materials 1 to 12, 42 to 50) and manufacturing conditions (any of manufacturing methods A to M) to obtain samples 1 to 12, 42 to 50, 58 to 69, 99 to 107, 115 to 136, 181 to 191, and the number of compounds, corrosion weight loss, and corrosion depth of each sample 1 to 12, 42 to 50, 58 to 69, 99 to 107, 115 to 136, 181 to 191 were measured.

[0065] i. Number of compounds (distribution state) From samples 1 to 12, 42 to 50, 58 to 69, 99 to 107, 115 to 136, 181 to 191, mechanical polishing and electrolytic polishing of the cut-out sample pieces were performed to produce thin films, and TEM (transmission electron microscope) was used to measure fine compounds and coarse compounds with an observation field of 10000 μm 2 (100 μm square). The presence or absence of Cr in the compounds was determined by EPMA for compounds larger than 1 μm and by EDS-based composition analysis for compounds 1 μm or less. Fine compounds are intermetallic compounds having a circular equivalent diameter of 0.01 μm or more and less than 5.00 μm. Coarse compounds are intermetallic compounds having a circular equivalent diameter exceeding 10 μm. Table 3 and Table 4 show the numbers of fine compounds and coarse compounds.

[0066] II. Film analysis of the corroded part of the rolled material The film on the corroded part of the test piece loaded in the SWAAT test for 24 hours was analyzed. After loading the test piece cut from the rolled material in the SWAAT test for 24 hours, the test piece was washed with pure water and dried sufficiently, and the presence or absence of Cr in the film was determined by performing XPS measurement on the surface layer of the material. The case where Cr was detected in the film was regarded as good, and the case where it was not detected was regarded as bad. Tables 3 and 4 show the film analysis results of each of Samples 1 to 12, 42 to 50, 58 to 69, 99 to 107, 115 to 136, and 181 to 191, with good being designated as A and bad being designated as C. The SWAAT test is a cycle test in which 5% NaCl at pH 3 is used as the corrosion solution, spraying is performed at 50 °C for 30 minutes, and wetting is performed at 50 °C for 90 minutes for one cycle. XPS measurement was performed every 1.2 nm in terms of the depth converted to SiO2 in terms of the sputtering time. The oxide film was defined as the range from the surface layer to the point where the concentrations of O and Al are reversed (O > Al on the surface layer side), and the presence or absence of Cr detection (a peak appearing near 574 eV when Cr is present) was determined at any measurement point in the oxide film.

[0067] III. Corrosion weight loss The test piece was cut out from the rolled material to 80 mm × 20 mm, one side and the edge were protected by masking, and the corrosion test was performed in a state of one-sided exposure. The corrosion test was loaded in the SWAAT test for 1320 hours and evaluated by the weight change (corrosion weight loss) before and after the corrosion test. When the corrosion weight loss is less than 5.0 mg / cm 2 it is regarded as good, and when the corrosion weight loss is less than 5.0 mg / cm 2 but not less than 10.0 mg / cm 2 it is regarded as slightly good, and when it is 10.0 mg / cm 2 or more, it is evaluated as bad. Tables 3 and 4 show the evaluation of the corrosion weight loss of each sample, with good being designated as A, slightly good being designated as B, and bad being designated as C.

[0068] IV. Corrosion depth After subjecting the test specimens cut from the rolled material to SWAAT for 1320 hours, the corrosion depth of the test specimens was evaluated. In this evaluation, first, the deepest corroded part on the exposed surface of the test specimen was identified using a non-contact step measuring instrument. Next, the cross-section was exposed by resin-embedding and polishing the identified location, and the thinnest thickness t1 of the test specimen after corrosion was measured by observation. The difference from the thickness t0 of the test specimen measured in advance before the SWAAT test was defined as the corrosion depth (=t0 - t1). A corrosion depth of less than 60 μm was considered good, a corrosion depth of 60 μm or more and less than 120 μm was considered somewhat good, and a corrosion depth of 120 μm or more was considered poor. Tables 3 and 4 show the evaluation of the corrosion depth of each of the test specimens 1 - 12, 42 - 50, 58 - 69, 99 - 107, 115 - 136, 181 - 191, with good being designated as A, somewhat good being designated as B, and poor being designated as C.

[0069] Ho. Evaluation of corrosion resistance The corrosion resistance of the specimens was evaluated from the corrosion weight loss and the corrosion depth. When both the evaluation of the corrosion weight loss and the evaluation of the corrosion depth were very good (A), it was considered extremely good. When one was good (A) and the other was somewhat good (B), it was considered good. When both were somewhat good (B), it was considered somewhat good. When either one was poor (C), it was considered poor. Tables 3 and 4 show the evaluation of the corrosion resistance of each of the test specimens 1 - 12, 42 - 50, 58 - 69, 99 - 107, 115 - 136, 181 - 191, with extremely good being designated as AA, good being designated as A, somewhat good being designated as B, and poor being designated as C.

[0070]

Table 3

[0071]

Table 4

[0072] In Samples 1 to 9, 58 to 66, and 115 to 118, a material containing Cr of 0.05% by mass or more and 1.00% by mass or less, Fe of 0.05% by mass or more and 1.00% by mass or less, and Si of 0.05% by mass or more and 1.50% by mass or less, with the balance being Al and inevitable impurities, and satisfying the relationship of 0.8Fe ≤ Si between the contents of Fe and Si, was used to produce a rolled material by any one of Manufacturing Methods A to F in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled. In Samples 49 and 106, a material containing Cr of 0.05% by mass or more and 1.00% by mass or less, Fe of 0.05% by mass or more and 1.00% by mass or less, and Si of 0.05% by mass or more and 1.50% by mass or less, and containing Ti outside the range of 0.05% by mass or more and 1.00% by mass or less, with the balance being Al and inevitable impurities, and satisfying the relationship of 0.8Fe ≤ Si between the contents of Fe and Si, was used to produce a rolled material by any one of Manufacturing Methods A and F in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled. As a result, a compound with a small cathodic reaction was preferentially generated, and fine intermetallic compounds containing Cr could be densely distributed, and coarse precipitates thereon could be suppressed. Furthermore, in the corroded part of the surface layer, it was confirmed that the corrosion loss was small, the corrosion depth was shallow, and an oxide film containing Cr in which the intermetallic compound was decomposed was formed, and the corrosion resistance was good.

[0073] In Samples 10 to 12, 67 to 69, and 126 to 129, a material containing Cr of 0.05% by mass or more and 1.00% by mass or less, Fe of 0.05% by mass or more and 1.00% by mass or less, Si of 0.05% by mass or more and 1.50% by mass or less, and Ti of 0.05% by mass or more and 1.00% by mass or less, with the balance being Al and inevitable impurities, and satisfying the relationship of 0.8Fe ≤ Si between the contents of Fe and Si, was used to produce a rolled material by any one of Manufacturing Methods A to F in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled. As a result, a compound with a small cathodic reaction was preferentially generated, and fine intermetallic compounds containing Cr could be densely distributed, and coarse precipitates thereon could be suppressed. Furthermore, in the corroded part of the surface layer, it was confirmed that the corrosion loss was small, the corrosion depth was shallow, and an oxide film containing Cr in which the intermetallic compound was decomposed was formed, and the corrosion resistance was good.

[0074] Samples 42, 99, 181 to 184 were produced by any of manufacturing methods A to F in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled, using material 42 with Cr outside the range of 0.05% by mass or more and 1.00% by mass or less. Also, samples 185 to 191 were produced by any of manufacturing methods G to M in which the manufacturing conditions of casting, homogenization treatment, and rolling were not controlled, using material 42 with Cr outside the range of 0.05% by mass or more and 1.00% by mass or less. Regardless of the control of the manufacturing conditions of casting, homogenization treatment, and rolling, it was confirmed that when the Cr content is low, the corrosion resistance is low.

[0075] Samples 119 to 125 contain Cr at 0.05% by mass or more and 1.00% by mass or less, Fe at 0.05% by mass or more and 1.00% by mass or less, and Si at 0.05% by mass or more and 1.50% by mass or less, with the balance being Al and inevitable impurities, and using material 1 in which the Fe and Si contents satisfy the relationship of 0.8Fe ≤ Si, were produced by any of manufacturing methods G to M in which any control of the manufacturing conditions of casting, homogenization treatment, and rolling was not performed. Samples 130 to 136 contain Cr at 0.05% by mass or more and 1.00% by mass or less, Fe at 0.05% by mass or more and 1.00% by mass or less, Si at 0.05% by mass or more and 1.50% by mass or less, and Ti at 0.05% by mass or more and 1.00% by mass or less, with the balance being Al and inevitable impurities, and using material 10 in which the Fe and Si contents satisfy the relationship of 0.8Fe ≤ Si, were produced by any of manufacturing methods G to M in which any control of the manufacturing conditions of casting, homogenization treatment, and rolling was not performed. Without controlling the manufacturing conditions of casting, homogenization treatment, and rolling, the distribution of fine intermetallic compounds and coarse intermetallic compounds could not be controlled, and the corrosion resistance was poor.

[0076] Samples 46, 48, 103, 105 were produced by any of manufacturing methods A, F in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled, using materials 46, 48 in which the Fe and Si contents do not satisfy the relationship of 0.8Fe ≤ Si. It was confirmed that when the relationship of the material does not satisfy 0.8Fe ≦ Si, the formation of coarse compounds (Al-Fe based compounds) becomes dominant and the corrosion resistance deteriorates.

[0077] Samples 43, 45, 47, 50, 100, 102, 104 and 107 are produced by either manufacturing method A or F that controls the manufacturing conditions of casting, homogenization treatment, and rolling using any of materials 43, 45, 47 and 50, but any of the contents of Cr, Fe, Si and Ti is high and the production of rolled materials could not be carried out. Also, samples 44 and 101 are produced by either manufacturing method A or F that controls the manufacturing conditions of casting, homogenization treatment, and rolling using material 44 with a low Fe content, but any of the contents of Cr, Fe, Si and Ti is high, and material 15 was not manufactured because the cost increases.

Example

[0078] The tensile strength Rm of rolled materials made of aluminum alloy manufactured by changing the material and manufacturing conditions was evaluated.

[0079] (Material) The materials used for the production of rolled materials made of aluminum alloy contain Cr, Fe, Si, and also contain any one or a plurality of elements of Ti, Mn, Mg, Cu, Zr, V, Sr, Sc, Mo, and the balance consists of Al and inevitable impurities. The mass % of Cr, Fe, Si, Ti, Mn, Mg, Cu, Zr, V, Sr, Sc, Mo of each material is as shown in Table 5. The materials 13 to 28 and 33 to 41 contain 0.05% to 1.00% by mass of Cr, 0.05% to 1.00% by mass of Fe, and 0.05% to 1.50% by mass of Si, and further contain any one or a plurality of elements of Ti, Mn, Mg, Zr, V, Sr, Sc, and Mo. The balance is Al and inevitable impurities, and the content of Fe and Si further satisfies the relationship of 0.8Fe ≤ Si. Here, Ti is 0.05% to 1.00% by mass, Mn is 0.10% to 2.00% by mass, Mg is 0.01% to 3.00% by mass, Cu is 0.01% to 1.00% by mass, and any one or a plurality of elements of Zr, V, Sr, Sc, and Mo are 0.01% to 0.50% by mass for each element. Hereinafter, the range of 0.10% to 2.00% by mass of Mn, the range of 0.01% to 3.00% by mass of Mg, the range of 0.01% to 1.00% by mass of Cu, and the range of 0.01% to 0.50% by mass for each element of any one or a plurality of elements of Zr, V, Sr, Sc, and Mo may all be referred to as the second composition range. The contents of Mn, Mg, and Cu in the materials 51 to 55 are not controlled within the second composition range.

[0080]

Table 5

[0081] (Manufacturing method) The manufacturing method of the aluminum alloy sheet material includes an ingot manufacturing process for manufacturing an ingot, a homogenization process for homogenizing the ingot, a facing process for facing the ingot, a soaking heat treatment process for subjecting the faced ingot to a soaking heat treatment, and a rolling process (hot rolling process and cold rolling process) for rolling the faced ingot. The manufacturing method is any one of the manufacturing methods A to M in Table 2 above.

[0082] Rolled materials were manufactured by changing the material (any one of Materials 13 to 28, 33 to 41, 51 to 55) and the manufacturing conditions (any one of Manufacturing Methods A to M), and were designated as Samples 13 to 28, 33 to 41, 51 to 55, 70 to 85, 90 to 98, 108 to 112, 137 to 158, 170 to 180. The strength of each of Samples 13 to 28, 33 to 41, 51 to 55, 70 to 85, 90 to 98, 108 to 112, 137 to 158, 170 to 180 was measured. Samples were cut out parallel to the rolling direction from each of Samples 13 to 28, 33 to 41, 51 to 55, 70 to 85, 90 to 98, 108 to 112, 137 to 158, 170 to 180, and No. 13 Type B test pieces were prepared according to the Metallic Materials - Tensile Testing Method (JIS Z2241:2011), and the tensile strength Rm was measured. The tensile strength Rm was judged as good when it was 140 MPa or more, slightly good when it was 100 MPa or more and less than 140 MPa, and poor when it was less than 100 MPa. Table 6 and Table 7 show the tensile strength Rm of each of Samples 13 to 28, 33 to 41, 51 to 55, 70 to 85, 90 to 98, 108 to 112, 137 to 158, 170 to 180, where good is represented as A, slightly good as B, and poor as C. Also, the measurement of the number of compounds, the film analysis at the corroded part of the rolled material, the corrosion weight loss, the corrosion depth, and the evaluation of corrosion resistance performed in Example 1 were similarly carried out for each of Samples 13 to 28, 33 to 41, 51 to 55, 70 to 85, 90 to 98, 108 to 112, 137 to 158, 170 to 180 in Example 2, and these measured values and evaluations are shown together in Table 6 and Table 7.

[0083]

Table 6

[0084]

Table 7

[0085] In Samples 13 - 28, 33 - 41, 70 - 85, 90 - 98, 137 - 158, and 170 - 180, with Mn at 0.10 mass% or more and 2.00 mass% or less, Mg at 0.01 mass% or more and 3.00 mass% or less, Cu at 0.01 mass% or more and 1.00 mass% or less, and any one or more of the elements Zr, V, Sr, Sc, and Mo at 0.01 mass% or more and 0.50 mass% or less per element, by using any of Materials 13 - 28 or 33 - 41 to which any one or more of the elements Mn, Mg, Zr, V, Sr, Sc, and Mo were added, the tensile strength Rm could be made good or slightly good. Among these, Samples 13 - 28, 33 - 41, 70 - 85, 90 - 98, 137 - 140, 148 - 151, and 170 - 173 had Cr at 0.05 mass% or more and 1.00 mass% or less, Fe at 0.05 mass% or more and 1.00 mass% or less, and Si at 0.05 mass% or more and 1.50 mass% or less, and by using any of Materials 13 - 28 or 33 - 41 where the content of Fe and Si satisfied the relationship 0.8Fe ≤ Si, and by manufacturing the rolled material by any of Manufacturing Methods A - F that controlled the manufacturing conditions of casting, homogenization treatment, and rolling, the corrosion resistance could also be made good. That is, compounds with a small cathodic reaction could be preferentially generated, fine intermetallic compounds containing Cr could be densely distributed, and coarse precipitates could be suppressed thereon. Furthermore, in the corroded part of the surface layer, it was confirmed that the corrosion loss was small, the corrosion depth was shallow, and an oxide film containing Cr in which the intermetallic compound was decomposed was formed, and the corrosion resistance was good. Samples 141 - 158 and 174 - 180 had good or slightly good tensile strength Rm, but used aluminum alloys manufactured without controlling the manufacturing conditions of casting, homogenization treatment, and rolling, and had poor corrosion resistance (C).

[0086] In Samples 55 and 112, a rolled material was produced by any of Manufacturing Methods A and F using Material 55 in which Cu was outside the second composition range. The tensile strength Rm of Samples 55 and 112 was slightly good, but there were few fine compounds and many coarse compounds, and the corrosion resistance was poor (C).

[0087] For Samples 51, 53, 108 and 110, rolled materials were produced by either Manufacturing Method A or F using Materials 51 and 53 with low Mn or Mg content. In these rolled materials, the tensile strength Rm was low and defective, but the corrosion resistance of Samples 51, 53, 108 and 110 was good or slightly good.

[0088] Samples 52, 54, 109 and 111 were to produce rolled materials using either Material 52 or 54 with high Mn or Mg content, but the production of the rolled materials could not be carried out.

Examples

[0089] The corrosion depth of a one-sided clad material using a rolled aluminum alloy material formed by changing the material and manufacturing conditions as a sacrificial material was evaluated.

[0090] (Material) As the material used for manufacturing the rolled aluminum alloy material, those containing Cr, Fe, Si, Zn and the balance consisting of Al and inevitable impurities were used. Some materials further contained Ti. Materials 29 to 31 contain 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, 0.05% by mass or more and 1.50% by mass or less of Si, 0.01% by mass or more and 8.00% by mass or less of Zn, with the balance being Al and inevitable impurities, and further satisfying the relationship of 0.8Fe ≤ Si for the contents of Fe and Si. Material 32 contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, 0.05% by mass or more and 1.50% by mass or less of Si, 0.05% by mass or more and 1.00% by mass or less of Ti, 0.01% by mass or more and 8.00% by mass or less of Zn, with the balance being Al and inevitable impurities, and further satisfying the relationship of 0.8Fe ≤ Si for the contents of Fe and Si. For Materials 56 and 57, the Zn content is not controlled within the range of 0.01% by mass or more and 8.00% by mass or less. The mass percentages of Cr, Fe, Si, Ti, and Zn in each of Materials 29 to 32, 56 and 57 are as shown in Table 8.

[0091]

Table 8

[0092] (Manufacturing method) The manufacturing method of the aluminum alloy sheet material includes an ingot manufacturing process for manufacturing an ingot, a homogenization process for homogenizing the ingot, a facing process for facing the ingot, a soaking heat treatment process for subjecting the faced ingot to soaking heat treatment, and a rolling process (hot rolling process and cold rolling process) for rolling the faced ingot. The manufacturing method is any one of the manufacturing methods A to M in Table 2 above.

[0093] (Evaluation of corrosion depth) A rolled material is produced from the material (any one of 29 to 32, 56, and 57) and the manufacturing conditions (any one of the manufacturing methods A to M), and further, using this rolled material as a sacrificial material, it is bonded to a core material made of an aluminum alloy of the JIS 3003 series to produce a single-sided clad material with a plate thickness of 0.2 mm and a clad ratio of 10%. After cladding, final annealing is performed at 360 °C for 3 hours to make the clad material in the O temper, and these are used as Samples 29 to 32, 56, 57, 86 to 89, 113 to 114, and 159 to 169. The corrosion depth of each of Samples 29 to 32, 56, 57, 86 to 89, 113 to 114, and 159 to 169 was measured and the corrosion depth was evaluated. A test piece cut out from the single-sided clad material was loaded in the SWAAT test for 1320 hours with the sacrificial material side exposed. The SWAAT test is a cycle test with a cycle of spraying 5% NaCl with a pH of 3 as a corrosion solution at 50 °C for 30 minutes and wetting at 50 °C for 90 minutes, similar to Example 1. In the evaluation, first, the deepest corroded part on the exposed surface of the test piece was identified using a non-contact step measuring instrument, and then the cross-section was exposed by resin embedding and polishing the identified location, and the thinnest thickness t1 of the test piece after corrosion was measured by observation, and the difference from the thickness t0 of the test piece measured in advance before the SWAAT test was taken as the corrosion depth (=t0 - t1). A corrosion depth of less than 15% of the plate thickness before the SWAAT test was judged as good, a corrosion depth of 15% or more and less than 35% of the plate thickness was judged as slightly good, and a corrosion depth of 35% or more of the plate thickness was judged as bad. Table 9 shows the evaluation of the corrosion depth of each of the samples 29 to 32, 56, 57, 86 to 89, 113 to 114, and 159 to 169, with good being designated as A, slightly good as B, and poor as C. Also, the measurement of the number of compounds and the film analysis of the corroded part of the rolled material performed in Example 1 were similarly carried out on the sacrificial materials of each sample in Example 3, and these measured values and evaluations are shown together in Table 9.

[0094]

Table 9

[0095] For samples 29 to 32, 86 to 89, and 159 to 162, by using any of the materials 29 to 32 with a Zn content of 0.01 mass% or more and 8.00 mass% or less, the corrosion depth could be made good (A) or slightly good (B). Also, Cr was detected in the film on the corroded part of the test specimen loaded with the SWAAT test.

[0096] For samples 56, 57, 113, and 114, rolled materials manufactured by either manufacturing method A or F using any of materials 56 and 57 outside the range of 0.01 mass% or more and 8.00 mass% or less in Zn content were used. The erosion depth of the sacrificial material made of this rolled material was poor (C). Also, Cr was detected in the film on the corroded part of the test specimens of samples 56, 57, 113, and 114 loaded with the SWAAT test.

[0097] For samples 163 to 169, rolled materials manufactured by any of manufacturing methods G to M using material 29 with a Zn content of 0.01 mass% or more and 8.00 mass% or less were used. The erosion depth of the sacrificial material made of this rolled material was poor (C). Also, Cr could not be detected in the film on the corroded part of the test specimens loaded with the SWAAT test.

Claims

1. It contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance consisting of Al and unavoidable impurities, Fe and Si satisfy the relationship of 0.8Fe ≤ Si, Intermetallic compounds containing Cr having a diameter equivalent to a circle of 0.01 μm or more and less than 5.00 μm are present in an observation field of view per 10,000 μm ２ in the parallel plane of RD-TD in a number of 10 or more, Furthermore, an aluminum alloy rolled material characterized in that the number of intermetallic compounds having a diameter equivalent to a circle of 10 μm or more is less than 3 in the observation field of view.

2. The rolled material according to Claim 1, characterized in that it contains 0.05% by mass or more and 1.00% by mass or less of Ti.

3. The rolled material according to Claim 1 or Claim 2, characterized in that it further contains any one or a plurality of elements selected from 0.10% by mass or more and 2.00% by mass or less of Mn, 0.01% by mass or more and 3.00% by mass or less of Mg, 0.01% by mass or more and 1.00% by mass or less of Cu, 0.01% by mass or more and 8.00% by mass or less of Zn, 0.01% by mass or more and 0.50% by mass or less of Zr, 0.01% by mass or more and 0.50% by mass or less of V, 0.01% by mass or more and 0.50% by mass or less of Sr, 0.01% by mass or more and 0.50% by mass or less of Sc, and 0.01% by mass or more and 0.50% by mass or less of Mo.

4. A clad material comprising a core material and a skin material directly or via an intermediate layer bonded to one or both sides of the core material, wherein the skin material contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, with the balance consisting of Al and unavoidable impurities, Fe and Si satisfy the relationship of 0.8Fe ≤ Si, Intermetallic compounds containing Cr having a diameter equivalent to a circle of 0.01 μm or more and less than 5.00 μm are present in an observation field of view of about 10,000 μm ２ per 10 or more in the RD-TD parallel plane, Furthermore, a clad material characterized in that the number of intermetallic compounds having a diameter equivalent to a circle of 10 μm or more is less than 3 in the observation field of view.

5. The clad material according to Claim 4, characterized in that the skin material contains 0.05% by mass or more and 1.00% by mass or less of Ti.

6. The clad material according to claim 4 or claim 5, wherein the skin material further contains any one or a plurality of elements selected from the group consisting of 0.10% by mass or more and 2.00% by mass or less of Mn, 0.01% by mass or more and 3.00% by mass or less of Mg, 0.01% by mass or more and 1.00% by mass or less of Cu, 0.01% by mass or more and 8.00% by mass or less of Zn, 0.01% by mass or more and 0.50% by mass or less of Zr, 0.01% by mass or more and 0.50% by mass or less of V, 0.01% by mass or more and 0.50% by mass or less of Sr, 0.01% by mass or more and 0.50% by mass or less of Sc, and 0.01% by mass or more and 0.50% by mass or less of Mo.

7. A brazing sheet comprising a core material made of an aluminum alloy and a brazing material bonded directly or via an intermediate layer to one or both sides of the core material, wherein the core material contains 0.05% by mass or more and 1.00% by mass or less of Cr, 0.05% by mass or more and 1.00% by mass or less of Fe, and 0.05% by mass or more and 1.50% by mass or less of Si, and the balance consists of Al and unavoidable impurities, Fe and Si satisfy the relationship of 0.8Fe ≤ Si, Intermetallic compounds containing Cr having a diameter equivalent to a circle of 0.01 μm or more and less than 5.00 μm are present in an observation field of view per 10,000 μm ２ or more in the RD-TD parallel plane, and further, the number of intermetallic compounds having a diameter of 10 μm or more in terms of equivalent circle diameter is less than 3 in the observation field of view.

8. The brazing sheet according to claim 7, wherein the core material contains 0.05% by mass or more and 1.00% by mass or less of Ti.

9. The brazing sheet according to claim 7 or claim 8, wherein the core material further contains any one or a plurality of elements selected from the group consisting of 0.10% by mass or more and 2.00% by mass or less of Mn, 0.01% by mass or more and 3.00% by mass or less of Mg, 0.01% by mass or more and 1.00% by mass or less of Cu, 0.01% by mass or more and 8.00% by mass or less of Zn, 0.01% by mass or more and 0.50% by mass or less of Zr, 0.01% by mass or more and 0.50% by mass or less of V, 0.01% by mass or more and 0.50% by mass or less of Sr, 0.01% by mass or more and 0.50% by mass or less of Sc, and 0.01% by mass or more and 0.50% by mass or less of Mo.

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