Brazing sheet

Abstract

To provide a brazing sheet.SOLUTION: A brazing sheet has a brazing material cladded on at least one surface of a core material, wherein the brazing material contains Si in an amount of 1.5 mass% or more and 14.0 mass% or less, one of V and Ti in an amount of 0.010 mass% or more and 1.5 mass% or less, with the balance consisting of Al and inevitable impurities, the core material contains the other one of V and Ti in an amount of 0.010 mass% or more and 0.5 mass% or less, with the balance consisting of Al and inevitable impurities, an RD-TD parallel surface of the brazing material has less than 5 intermetallic compounds containing one of V and Ti having a diameter of 10.000 μm or more in a circle equivalent diameter in an observation visual field of 10000 μm2, and an RD-TD parallel surface of the core material has 10 or more intermetallic compounds containing the other one of V and Ti having a diameter of 0.01 μm or more and less than 5.00 μm in a circle equivalent diameter in an observation visual field of 10000 μm2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a brazing sheet. [Background technology]

[0002] Heat exchangers made from aluminum alloys use brazing to join the various components. Brazing is done by using a brazing sheet made of an Al-Si alloy with a solidus temperature of 580°C or less, attached to a core material, and then melting only the brazing material through heat treatment at around 600°C. The molten brazing material flows between the components and cools, achieving a strong metallic bond. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-17116 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional brazing is an excellent technology that can firmly join many joints at once, but it also has some challenges. Brazing involves high-temperature heat treatment of a heat exchanger structure, but because there are various parts with different thicknesses, sizes, arrangements, and shapes, there are differences in the rate at which these parts heat up. In other words, parts that heat up easily may be exposed to a high-temperature environment for longer than parts that heat up more slowly, or they may even overheat. When this happens, the molten brazing filler metal erodes the core material, significantly affecting the material's strength and corrosion resistance.

[0005] To address this erosion of the core material by the molten brazing filler metal, Patent Document 1 improves the erosion resistance of the brazing sheet by coarsening the recrystallized grains of the core material during brazing heating. However, the molten brazing filler metal can be concentrated locally due to capillary force or gravity, and if an excessive amount of molten brazing filler metal is supplied, there is a risk that the erosion resistance will not be achieved.

[0006] Therefore, an object of the present invention is to provide a brazing sheet having excellent erosion resistance. [Means for solving the problem]

[0007] In response to the above-mentioned problems, the inventors discovered that by including one of V and Ti in the brazing filler metal and the other of V and Ti in the core metal, and further controlling the distribution of coarse compounds containing one of V and Ti in the brazing filler metal, and controlling the distribution of fine compounds containing the other of V and Ti in the core metal, when the clad material is heat-treated, a high-melting-point compound is generated between one of V and Ti in the molten brazing filler metal (hereinafter, the "molten brazing filler metal" may be referred to as the molten brazing filler metal) and the other of V and Ti in the core metal, thereby reducing erosion of the core material by the molten brazing filler metal.

[0008] The present invention provides a brazing sheet having a brazing filler metal clad on at least one surface of a core material, wherein the brazing filler metal contains 1.5 mass% or more and 14.0 mass% or less of Si, 0.010 mass% or more and 1.5 mass% or less of one of V and Ti, and the balance being Al and unavoidable impurities, and the core material contains 0.010 mass% or more and 0.5 mass% or less of the other of V and Ti, and the balance being Al and unavoidable impurities, and the RD-TD parallel plane of the brazing filler metal has a thickness of 10,000 μm. 2 In the observation field of the core material, there are less than five intermetallic compounds having a circle equivalent diameter of 10.00 μm or more and containing one of the two, and the RD-TD parallel plane of the core material is 10,000 μm 2 The present invention is characterized in that, in the observation field, there are 10 or more intermetallic compounds each having a circle-equivalent diameter of 0.01 μm or more and less than 5.00 μm and containing the other intermetallic compound.

[0009] Specifically, when the brazing filler metal contains one of V and Ti and the core material contains the other of V and Ti, if the brazing filler metal contains V, the core material contains Ti, and if the brazing filler metal contains Ti, the core material contains V.

[0010] [Brazing material] Si: 1.5% by mass or more and 14.0% by mass or less Silicon is added to form a fillet at the joint during brazing. If the silicon content is less than 1.5 mass%, the brazing filler will be insufficient and the joint will be insufficient. If the silicon content exceeds 14.0 mass%, the material will become hard and brittle, making it difficult to manufacture.

[0011] Ti: 0.010 mass% or more and 1.5 mass% or less When the molten brazing filler metal erodes the core material, the Ti in the brazing filler metal forms a high-melting point compound with the V contained in the core material as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the Ti content is less than 0.010 mass%, the effect is insufficient, but if the Ti content exceeds 1.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0012] V: 0.010 mass% or more and 1.5 mass% or less When the molten brazing filler metal erodes the core material, the V in the brazing filler metal forms a high-melting point compound with the Ti contained in the core material as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the V content is less than 0.010 mass%, the effect is insufficient, and if the V content exceeds 1.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0013] The RD-TD parallel plane of the brazing material has a circle equivalent diameter of 10.00 μm or more, and is 10,000 μm of an intermetallic compound containing either V or Ti. 2 The distribution of coarse intermetallic compounds is controlled by limiting the number of particles per unit area to less than 5. RD is the rolling direction, TD is the transverse direction perpendicular to the RD and normal direction, and the RD-TD parallel plane of the brazing material is a plane parallel to the rolling direction and the transverse direction, and is a plane formed by scraping the surface of the brazing sheet. If the intermetallic compound containing either V or Ti in the brazing filler metal is coarse, the intermetallic compound is difficult to decompose when the brazing filler metal is melted, the amount of V or Ti in the molten braze is reduced, and when the molten braze takes in the core material, sufficient reaction with the other of V and Ti added to the core material is not achieved, making it impossible to reduce erosion of the core material by the molten braze.

[0014] [Heartwood] Ti: 0.010 mass% or more and 0.5 mass% or less When the molten brazing filler metal erodes the core material, the Ti in the core material forms a high-melting-point compound with the V contained in the brazing filler metal as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the Ti content is less than 0.010 mass%, the effect is insufficient, and if the Ti content exceeds 0.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0015] V: 0.010 mass% or more and 0.5 mass% or less When the molten brazing filler metal erodes the core material, the V in the core material forms a high-melting-point compound with the Ti contained in the brazing filler metal as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the V content is less than 0.010 mass%, the effect is insufficient, and if the V content exceeds 0.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0016] The upper limits of the Ti and V contents of the brazing filler metal are set higher than the upper limits of the Ti and V contents of the core metal. When the Si content is high, the solidus temperature of aluminum drops significantly, which lowers the temperature at which compounds derived from Ti and V crystallize, and the V content at which coarse intermetallic compounds form or the Ti content shifts to the higher side. Therefore, the upper limits of Ti and V in the brazing filler metal are higher than those in the core metal.

[0017] The RD-TD parallel plane of the core material has a circle equivalent diameter of 0.01 μm or more and less than 5.00 μm, and is 10,000 μm of an intermetallic compound containing V or Ti. 2The distribution of fine intermetallic compounds is controlled by setting the number of particles per square inch to 10 or more. The RD-TD parallel surface of the core material is a surface parallel to the rolling direction and the cross direction, and is formed by scraping the surface of the brazing sheet down to the inside of the core material.

[0018] The core material contains fine intermetallic compounds containing V or Ti, with a particle size of 10,000 μm. 2 By distributing 10 or more per molten solder, when the molten solder takes in the core material, the core material supplies the other of V and Ti to the molten solder containing one of V and Ti, and one of the Ti and V in the solder material and the other of the V and Ti in the core material form a compound, thereby reducing erosion of the core material by the molten solder. 10,000 μm of intermetallic compound in the core 2 If the number per unit area is less than 10, the erosion of the core material by the molten brazing filler metal cannot be reduced.

[0019] In the brazing sheet of the present invention, the core material may further contain any one of the following additional elements 1 to 4, or any combination of two or more thereof. The core material further contains, as additional elements 1, 0.10 mass % to 2.0 mass % of Mn, 0.05 mass % to 1.5 mass % of Si, 0.05 mass % to 1.0 mass % of Fe, and 0.010 mass % to 2.0 mass % of Cu.

[0020] Mn: 0.10 mass% or more and 2.0 mass% or less By including Mn in the core material, intermetallic compounds such as Al-Mn, Al-Mn-Si, and Al-Mn-Si-Fe compounds are precipitated, improving the strength of the material. If the Mn content is less than 0.10% by mass, the effect is insufficient, and if the Mn content exceeds 2.0% by mass, coarse intermetallic compounds are formed during casting, resulting in a decrease in rollability.

[0021] Si in heartwood: 0.05% by mass or more and 1.5% by mass or less The Si content of the core material not only improves material strength through solid solution, but also precipitates as Al-Mn-Si or Al-Mn-Si-Fe intermetallic compounds, which improves material strength. If the Si content of the core material is less than 0.05% by mass, sufficient effect cannot be obtained, and if the Si content of the core material exceeds 1.5% by mass, the solidus temperature drops and the core material will not be able to maintain its shape during brazing.

[0022] Fe: 0.05 mass% or more and 1.0 mass% or less Fe is added to improve material strength by precipitating as intermetallic compounds such as Al-Mn-Fe and Al-Mn-Si-Fe. If the Fe content is less than 0.05% by mass, costs increase, while if the Fe content exceeds 1.0% by mass, coarse intermetallic compounds (crystallized particles) form during casting, reducing rollability.

[0023] Cu: 0.010 mass% or more and 2.0 mass% or less Cu is added to form a solid solution to improve material strength. If the Cu content is less than 0.010 mass%, the effect is insufficient, but if the Cu content exceeds 2.0 mass%, the material strength becomes too high, making it difficult to manufacture the material.

[0024] The core material further contains, as an additional element 2, Mg in an amount of 0.01% by mass or more and 1.0% by mass or less.

[0025] Mg: 0.01 mass% or more and 1.0 mass% or less Mg is added to improve material strength by precipitating as a solid solution or intermetallic compounds such as Mg2Si. If the Mg content is less than 0.01% by mass, the effect is insufficient, while if the Mg content exceeds 1.0% by mass, the material strength becomes too high, making it difficult to manufacture the material.

[0026] The core material further contains, as an additional element 3, Zn in an amount of 0.01 mass % or more and 5.0 mass % or less.

[0027] Zn in heartwood: 0.01% by mass or more and 5.0% by mass or less Zn in the core material is added to reduce the corrosion rate of the sacrificial protective material by dissolving in solid solution and making the natural potential less noble, thereby controlling the potential difference with the sacrificial protective material. If the Zn content of the core material is less than 0.01% by mass, the effect is insufficient, but if the Zn content of the core material exceeds 5.0% by mass, the potential becomes too noble, reducing the self-corrosion resistance.

[0028] The core material further contains, as additional elements 4, one or more of 0.01 mass % to 0.35 mass % of Cr, 0.01 mass % to 0.35 mass % of Zr, and 0.01 mass % to 1.0 mass % of Sr.

[0029] Cr: 0.01 mass% or more and 0.35 mass% or less Cr is added to form intermetallic compounds to improve material strength. If the Cr content is less than 0.01% by mass, the effect is insufficient, while if the Cr content exceeds 0.35% by mass, coarse intermetallic compounds are formed during casting, reducing rollability.

[0030] Zr: 0.01 mass% or more and 0.35 mass% or less Zr is added to form intermetallic compounds to improve material strength. If the Zr content is less than 0.01% by mass, the effect is insufficient, while if the Zr content exceeds 0.35% by mass, coarse intermetallic compounds are formed during casting, reducing rollability.

[0031] Sr: 0.01 mass% or more and 1.0 mass% or less Sr is added to form intermetallic compounds to improve material strength. If the Sr content is less than 0.01% by mass, the effect is insufficient, while if the Sr content exceeds 1.0% by mass, coarse intermetallic compounds are formed during casting, reducing rollability.

[0032] In the brazing sheet of the present invention, the brazing filler metal preferably further contains 0.01 mass % to 5.0 mass % of Zn.

[0033] Zn: 0.01 mass% or more and 5.0 mass% or less Zn forms a potential gradient through solid solution and diffusion that causes the natural potential to change from noble to noble from the surface layer of the material in the depth direction, causing the corrosion to become planar, significantly improving the through-thickness life during material corrosion. If the Zn content is less than 0.01% by mass, sufficient effect cannot be obtained, and if the Zn content exceeds 5.0% by mass, the potential becomes excessively noble, increasing the rate of self-corrosion.

[0034] The brazing sheet of the present invention has, for example, one surface formed of a brazing material and the other surface formed of a sacrificial material. [Effects of the Invention]

[0035] According to the present invention, one of the V and Ti in the molten brazing filler metal and the other of the V and Ti in the core material are sufficiently reacted to form a compound with a high melting point, thereby reducing erosion of the core material by the molten brazing filler metal. DETAILED DESCRIPTION OF THE INVENTION

[0036] A brazing sheet according to an embodiment of the present invention will be described. A brazing sheet comprises a core material made of an aluminum alloy and a brazing filler metal made of an aluminum alloy clad on at least one surface of the core material. The surface formed by the brazing filler metal is brought into contact with another member, such as an aluminum plate or a copper plate, and heated, thereby joining the core material to the other member with the brazing filler metal.

[0037] In a brazing sheet, the brazing filler metal contains one of V and Ti, and the core material contains the other of V and Ti. Specifically, if the core material contains Ti, the brazing filler metal contains V, and if the core material contains V, the brazing filler metal contains Ti. Hereinafter, a brazing sheet in which the brazing filler metal contains V and the core material contains Ti may be referred to as a surface V-containing type, and a brazing sheet in which the brazing filler metal contains Ti and the core material contains V may be referred to as a surface Ti-containing type.

[0038] [Brazing material] The composition of the brazing filler metal is 1.5 mass % to 14.0 mass % Si, 0.010 mass % to 1.5 mass % of one of V and Ti, and the balance being Al and unavoidable impurities.

[0039] Si: 1.5% by mass or more and 14.0% by mass or less Silicon is added to form molten brazing fillets during brazing and to form fillets at the joint. If the Si content is less than 1.5% by mass, there will be insufficient molten brazing filler. If the Si content exceeds 14.0% by mass, the material will become hard and brittle, making it difficult to manufacture.

[0040] V: 0.010 mass% or more and 1.5 mass% or less When the molten brazing filler metal erodes the core material, the V in the brazing filler metal forms a high-melting point compound with the Ti contained in the core material as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the V content is less than 0.010 mass%, the effect is insufficient, and if the V content exceeds 1.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0041] Ti: 0.010 mass% or more and 1.5 mass% or less When the molten brazing filler metal erodes the core material, the Ti in the brazing filler metal forms a high-melting point compound with the V contained in the core material as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the Ti content is less than 0.010 mass%, the effect is insufficient, but if the Ti content exceeds 1.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0042] The RD-TD parallel plane of the brazing material has a circle equivalent diameter of 10.00 μm or more, and the intermetallic compound containing V or Ti has a diameter of 10,000 μm or more. 2 The distribution of coarse intermetallic compounds is controlled by limiting the number of particles per unit area to less than 5. The RD-TD parallel surface of the brazing filler metal is a surface parallel to the RD (rolling direction) and TD (transverse direction), and is formed by scraping the surface of the brazing sheet. If the intermetallic compounds containing V or Ti in the brazing filler metal are coarse, the intermetallic compounds are difficult to decompose when the brazing filler metal is melted. If the amount of V or Ti in the molten brazing filler metal is reduced, the V in the molten brazing filler metal and the Ti in the core material do not react sufficiently, or the Ti in the molten brazing filler metal and the V in the core material do not react sufficiently, and the erosion of the core material by the molten brazing filler metal cannot be reduced.

[0043] [Heartwood] The composition of the core material contains 0.010 mass % or more and 0.5 mass % or less of V or Ti, with the balance being Al and unavoidable impurities.

[0044] V: 0.010 mass% or more and 0.5 mass% or less When the molten brazing filler metal erodes the core material, the V in the core material forms a high-melting-point compound with the Ti contained in the brazing filler metal as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the V content is less than 0.010 mass%, the effect is insufficient, and if the V content exceeds 0.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0045] Ti: 0.010 mass% or more and 0.5 mass% or less When the molten brazing filler metal erodes the core material, the Ti in the core material forms a high-melting-point compound with the V contained in the brazing filler metal as a different layer at the brazing filler metal / core material interface, reducing the erosion of the core material by the molten brazing filler metal. If the Ti content is less than 0.010 mass%, the effect is insufficient, and if the Ti content exceeds 0.5 mass%, coarse intermetallic compounds are formed during casting, reducing rollability.

[0046] The core material can contain more V and Ti than the brazing filler metal, and the upper limits of the V and Ti contents of the brazing filler metal are set higher than the upper limits of the V and Ti contents of the core material. This is because a high Si content significantly lowers the solidus temperature of aluminum, and this lowering of the temperature at which V-derived compounds or Ti-derived compounds crystallize lowers, shifting the V or Ti content at which coarse intermetallic compounds form to a higher value.

[0047] The RD-TD parallel plane of the core material has a circle equivalent diameter of 0.01 μm or more and less than 5.00 μm, and is 10,000 μm of an intermetallic compound containing V or Ti. 2 The distribution of fine intermetallic compounds is controlled by setting the number of particles per square inch to 10 or more. The RD-TD parallel surface of the core material is a surface parallel to the RD (rolling direction) and TD (transverse direction), and is formed by scraping the surface of the brazing sheet down to the inside of the core material. The core material contains fine intermetallic compounds containing V or Ti, with a particle size of 10,000 μm. 2 By distributing 10 or more particles per 10000μm, when the molten brazing filler metal takes in the core material, the core material supplies V or Ti to the molten brazing filler metal containing V or Ti. This allows the V in the molten brazing filler metal to react with the Ti in the core material to form a compound, or the Ti in the molten brazing filler metal to react with the V in the core material to form a compound, thereby reducing the erosion of the core material by the molten brazing filler. 2 If the number per unit area is less than 10, the erosion of the core material by the molten brazing filler metal cannot be reduced.

[0048] (Brazing sheet manufacturing method) The manufacturing method of the brazing sheet comprises a brazing material manufacturing process, a core material manufacturing process, and a clad material manufacturing process.

[0049] A. Brazing material manufacturing process The brazing material manufacturing process includes an ingot manufacturing process for manufacturing an ingot, a homogenizing process for homogenizing the ingot, a facing process for facing the ingot, a soaking process for soaking the faced ingot, and a hot rolling process for rolling the soaked ingot.

[0050] A-1. Ingot manufacturing process The ingot manufacturing process involves producing ingots (slabs) by casting. The ingot for the brazing material is made of an aluminum alloy containing 1.5 mass % to 14.0 mass % of Si, 0.010 mass % to 1.5 mass % of V or Ti, and the balance being Al and unavoidable impurities. The casting temperature is 640°C or higher and lower than 710°C, preferably 660°C or higher and lower than 690°C. If the casting temperature is lower than 640°C, the time spent in the crystallization temperature range during casting is prolonged, resulting in the formation of coarse intermetallic compounds that cannot be sufficiently crushed during the rolling process. If the casting temperature is higher than 710°C, molten metal leakage will occur, making production impossible. The cooling rate is 0.10°C / sec or more, preferably 1°C / sec or more. If the cooling rate during casting is less than 0.10°C / sec, the time spent in the crystallization temperature range during casting will be long, and coarse intermetallic compounds will be generated that cannot be sufficiently crushed in the rolling process.

[0051] To improve the corrosion resistance of the clad material, the ingot may be produced by adding Zn, the amount of Zn being 0.01% by mass or more and 5.0% by mass or less.

[0052] A-2. Homogenization process In the homogenization step, the ingot is heated to a temperature of 400° C. or higher and lower than 510° C., and preferably maintained at a temperature of 430° C. or higher and lower than 490° C. The holding time is 1 hour or longer and 3 hours or shorter. The homogenization treatment rounds the corners of the eutectic Si in the ingot, improving the strength of the brazing filler metal and extending its lifespan. If the homogenization treatment temperature is less than 400°C, the brazing filler metal cannot have the desired strength. If the homogenization treatment temperature is 510°C or higher, the shape of the coarse intermetallic compounds containing V or Ti becomes closer to spheres, making them less likely to be crushed during the subsequent rolling process.

[0053] A-3. Facing process In the facing process, the top and bottom surfaces of the ingot are faced to remove segregated areas and oxide films.

[0054] A-4.Soaking process In the soaking step, the ingot is held at a temperature of, for example, 430° C. or higher and 530° C. or lower for 1 hour or higher and 12 hours or lower before being processed.

[0055] A-5. Hot rolling process In the hot rolling process, the facing ingot is rolled to form a rolled material, which is used as a brazing filler metal.

[0056] [Equivalent strain in hot rolling] In the hot rolling process, the condition is that the equivalent strain ε in the hot rolling, as shown in the following formula (1), exceeds 2.0 (ε>2.0). ε=(2 / √3)ln(t0 / t) Equation (1)

[0057] Here, t0 is the thickness of the slab (face-ground ingot) before the hot rolling process, and t is the thickness of the plate finished after the hot rolling process. By controlling the hot rolling so as to satisfy the above condition (ε>2.0), it is possible to crush the coarse intermetallic compounds generated during casting.

[0058] B. Heartwood manufacturing process The core material manufacturing process includes an ingot manufacturing process for manufacturing an ingot, a homogenizing process for homogenizing the ingot, and a facing process for facing the ingot.

[0059] B-1. Ingot manufacturing process The ingot manufacturing process involves producing ingots (plate-shaped slabs) by casting. The ingot for the core material is made of an aluminum alloy containing 0.010% by mass or more and 0.5% by mass or less of V or Ti, with the remainder being Al and unavoidable impurities. When the brazing filler metal contains V, the ingot for the core material contains Ti, and when the brazing filler metal contains Ti, the ingot for the core material contains V. The casting method is not particularly limited, and a conventional method can be used. In order to improve the strength of the core material, the ingot may be constructed by adding any one of the additional elements 1 to 4 or any combination of a plurality of additional elements.

[0060] The additive elements 1 are Mn, Si, Fe, and Cu. The additive amount of Mn is 0.10% by mass or more and 2.0% by mass or less, the additive amount of Si is 0.05% by mass or more and 1.5% by mass or less, the additive amount of Fe is 0.05% by mass or more and 1.0% by mass or less, and the additive amount of Cu is 0.010% by mass or more and 2.0% by mass or less.

[0061] The additional element 2 is Mg. The amount of Mg added is 0.01% by mass or more and 1.0% by mass or less.

[0062] The additional element 3 is Zn. The amount of Zn added is 0.01 mass % or more and 5.0 mass % or less.

[0063] The additional element 4 is any one or a combination of Cr, Zr, and Sr. The amount of Cr added is 0.01% by mass or more and 0.35% by mass or less, the amount of Zr added is 0.01% by mass or more and 0.35% by mass or less, and the amount of Sr added is 0.01% by mass or more and 1.0% by mass or less.

[0064] B-2. Homogenization process In the homogenization process, the ingot is heated to a temperature of 400°C or higher but lower than 600°C, and then maintained at a temperature of preferably 430°C or higher but lower than 580°C. The holding time is 1 hour or higher but 12 hours or lower, and preferably 3 hours or higher but 10 hours or lower. The homogenization treatment promotes the precipitation and growth of intermetallic compounds containing V or Ti. If the homogenization treatment temperature is lower than 400°C, sufficient precipitation and growth of intermetallic compounds cannot be obtained, while if the homogenization treatment temperature is higher than 600°C, the intermetallic compounds will grow coarsely.

[0065] B-3. ​​Facing process The top and bottom surfaces of the ingot are chamfered to remove segregated areas and oxide films.

[0066] The manufacturing method and conditions for the core ingot (plate-shaped slab) are not limited to those described above, as long as the ingot is suitable for cladding the rolled material.

[0067] C. Clad material manufacturing process The clad material manufacturing process includes an assembly process in which the rolled material is assembled onto an ingot (plate-shaped slab) for the core material, a soaking process in which the rolled material and the ingot for the core material are soaked, a hot rolling process in which the rolled material and the ingot (plate-shaped slab) are rolled and bonded together to form the clad material, and a cold rolling process in which the clad material formed in the hot rolling process is thinned.

[0068] C-1.Soaking process In the soaking process, the rolled material and the ingot (plate-shaped slab) are stacked together after the assembly process and are maintained at a temperature of, for example, 430°C to 530°C for 1 hour to 12 hours. When forming a brazing sheet into a double-sided clad type, the ingot (plate-shaped slab) is sandwiched between two rolled materials.

[0069] C-2. Hot rolling process In the hot rolling step, the rolling time between 400°C and 500°C is 5 minutes or more, preferably 10 minutes or more. By rolling for 5 minutes or more in the high temperature range between 400°C and 500°C, during which dynamic strain is introduced, the precipitation of fine intermetallic compounds containing V or Ti and having an equivalent circle diameter of 0.01 μm or more and less than 5.00 μm is promoted in the core material. If the rolling time between 400°C and 500°C is less than 5 minutes, the fine intermetallic compounds cannot be sufficiently distributed.

[0070] C-3. Cold rolling process In the cold rolling process, the reduction rate per pass is set to 25% or more for plate thicknesses of 0.5 mm or more, which crushes the coarse intermetallic compounds containing V or Ti in the core material and allows for the dense distribution of fine intermetallic compounds containing V or Ti. Through this clad material manufacturing process, a brazing sheet is completed in which the brazing material is clad on the core material. If necessary, intermediate annealing may be performed on the clad material between the hot rolling process and the cold rolling process, or during the cold rolling process, and final annealing may be performed on the clad material after the cold rolling process. The intermediate annealing and final annealing are performed, for example, by holding the temperature at 200°C to 450°C for 1 hour to 12 hours. If only intermediate annealing is performed, the brazing sheet will be tempered H1n, and if final annealing is performed, it will be tempered H2n or O depending on the annealing conditions.

[0071] Brazing sheets are used, for example, in the manufacture of heat exchanger components, and components made of brazing sheets with brazing filler metal are brazed to other components. The brazing conditions are, for example, to place the sheet in a heating furnace, heat it up to 600°C at an average heating rate of 100°C / min, hold it at 600°C for 3 minutes, then cool it down to 150°C at a cooling rate of 100°C / min, and then air-cool it to room temperature.

[0072] Because the components of a heat exchanger vary in thickness, size, arrangement, and shape, differences in their heating rates occur. Even if a brazing sheet-equipped component using this embodiment is exposed to a high-temperature environment for a longer period of time than a component that is more difficult to heat, causing the brazing material in the brazing component to melt, the brazing material contains a sufficient amount of either V or Ti because the brazing material is formed with a controlled distribution of small coarse intermetallic compounds. Meanwhile, the core material of the brazing component contains a tightly controlled distribution of fine intermetallic compounds containing either V or Ti. This allows V and Ti to react at the interface between the brazing material and the core material to form a high-melting-point compound. The formation of this compound reduces erosion of the core material by the molten brazing material.

[0073] By using the brazing sheet of this embodiment for parts exposed to high-temperature environments, the degree of freedom in controlling the brazing process is improved, shortening the brazing process time and enabling multiple brazing, etc. This also saves energy in the brazing heat treatment process, which can reduce CO2 emissions.

[0074] The brazing filler metal contains either V or Ti, and the distribution of coarse intermetallic compounds with a circle equivalent diameter of 10.00 μm or more is 10,000 μm 2If the number of V and Ti particles is not controlled to less than 5 per 10000 μm, the V and Ti particles contained in the core material cannot react sufficiently with the other of the V and Ti particles. 2 If the number is not controlled to 10 or more per atom, the V and Ti contained in the brazing material cannot react sufficiently with the other.

[0075] Previously, materials have been developed to prevent erosion of core materials by molten brazing filler metal, but these have not been sufficient. Brazing heat treatment requires enormous amounts of energy and precise control of factors such as temperature rise and hold times, heat exchanger placement, and heat application. The brazing sheet of an embodiment of the present invention eliminates the need for precise control of heat treatment equipment, shortening the brazing process time and improving the flexibility of brazing process control. Furthermore, the use of the brazing sheet of an embodiment of the present invention reduces erosion by molten brazing filler metal, enabling the manufacture of products and parts with excellent strength and corrosion resistance, and allowing them to be used for a long period of time. This also contributes to energy savings in the brazing heat treatment process, which has become increasingly important in recent years as a means of reducing CO2 emissions.

[0076] The present invention can be implemented without being limited to the above description. The parts of the present invention can be used as materials for assemblies in which parts are joined together by heat treatment, for example, as headers, tubes, fins, etc. in radiators, condensers, etc. Furthermore, they can be used as plates in stacked heat exchangers such as oil coolers. [Example]

[0077] Brazing sheets with brazing material clad on one side were produced using different materials and manufacturing conditions, and the erosion resistance of the core material due to molten brazing material was evaluated.

[0078] (material) The brazing sheet is configured as a surface V-containing type or a surface Ti-containing type, and the Si, V, and Ti contents of each material (ingot) used to form the brazing material and core material are shown in Table 1. Materials 1 to 3 are materials for producing a surface V-containing brazing sheet, and the ingot for the brazing material is an aluminum alloy containing 1.5% by mass to 14.0% by mass of Si, 0.010% by mass to 1.5% by mass of V, and the balance being Al and unavoidable impurities.Furthermore, the ingot for the core material is an aluminum alloy containing 0.010% by mass to 0.5% by mass of Ti, and the balance being Al and unavoidable impurities.

[0079] Materials 4 to 6 are materials for producing surface Ti-containing brazing sheets, and the ingot for the brazing material is made of an aluminum alloy containing 1.5 mass% to 14.0 mass% Si, 0.010 mass% to 1.5 mass% Ti, and the balance being Al and unavoidable impurities.Furthermore, the ingot for the core material is made of an aluminum alloy containing 0.010 mass% to 0.5 mass% V, and the balance being Al and unavoidable impurities.

[0080] Materials 29 and 30 are materials for producing a surface V-containing brazing sheet, in which the ingot (plate-shaped slab) for the brazing material is an aluminum alloy containing Si and V, with the balance being Al and unavoidable impurities, and the ingot (plate-shaped slab) for the core material is an aluminum alloy containing Ti, with the balance being Al and unavoidable impurities, but the Si content of the ingot for the brazing material is outside the range of 1.5 mass% or more and 14.0 mass% or less.

[0081] Materials 31 and 32 are materials for producing a surface V-containing brazing sheet, and the ingot for the brazing material is an aluminum alloy containing Si and V, with the balance being Al and unavoidable impurities, and the ingot for the core material is an aluminum alloy containing Ti, with the balance being Al and unavoidable impurities, but the V content of the ingot for the brazing material is outside the range of 0.010 mass% or more and 1.5 mass% or less.

[0082] Materials 33 and 34 are materials for producing a surface V-containing brazing sheet, in which the ingot for the brazing material is an aluminum alloy containing Si and V, with the balance being Al and unavoidable impurities, and the ingot for the core material is an aluminum alloy containing Ti, with the balance being Al and unavoidable impurities, but the Ti content of the ingot for the core material is outside the range of 0.010 mass% or more and 0.5 mass% or less.

[0083] Materials 36 and 37 are materials for producing a surface Ti-containing brazing sheet, in which the ingot for the brazing material is made of an aluminum alloy containing Si and Ti with the balance being Al and unavoidable impurities, and the ingot for the core material is made of an aluminum alloy containing V with the balance being Al and unavoidable impurities, but the Ti in the ingot for the brazing material is outside the range of 0.010 mass% or more and 1.5 mass% or less. In the material 35, the ingot for the brazing material and the ingot for the core material contain V, but neither contains Ti. In the material 38, the ingot for the brazing material and the ingot for the core material contain Ti, but neither contains V.

[0084] [Table 1]

[0085] (Brazing sheet manufacturing method) The manufacturing method of the brazing sheet comprises a brazing material manufacturing process, a core material manufacturing process, and a clad material manufacturing process.

[0086] a. Brazing material manufacturing process The brazing material manufacturing process includes an ingot manufacturing process for manufacturing an ingot, a homogenizing process for homogenizing the ingot, a facing process for facing the ingot, a soaking process for soaking the faced ingot, and a hot rolling process for rolling the soaked ingot.

[0087] a-1. Ingot manufacturing process The ingot manufacturing process involves producing ingots (slabs) by casting. The pouring temperature is 640°C or higher and lower than 710°C. The cooling rate is 0.10°C / sec or more.

[0088] a-2. Homogenization process In the homogenization process, the ingot is heated to a temperature of 400°C or higher but lower than 510°C and maintained at this temperature for two hours.

[0089] a-3. Facing process In the facing process, the top and bottom surfaces of the ingot are faced to remove segregated areas and oxide films.

[0090] a-4.Soaking process In the soaking treatment step, the ingot is held at a temperature of 430°C or higher and 530°C or lower for 1 hour or higher and 12 hours or shorter before processing the ingot.

[0091] a-5. Hot rolling process In the hot rolling process, the facing ingot is rolled to form a rolled material, which is used as a brazing filler metal.

[0092] (equivalent strain in hot rolling) In the hot rolling step, the condition is that the equivalent strain ε in the hot rolling represented by the above formula (1) exceeds 2.0 (ε>2.0).

[0093] b. Core material manufacturing process (slabs for core materials) The plate-shaped slabs are produced through homogenization and facing.

[0094] In the homogenization process, the core ingot is heated to a temperature of 400°C or higher and lower than 600°C and maintained at this temperature for 8 hours.

[0095] The upper and lower surfaces of the ingot for the core material are then chamfered to remove segregated areas and oxide films, and the resulting product is made into a plate-shaped slab for the core material.

[0096] c. Clad material manufacturing process The clad material manufacturing process includes an assembly process in which the rolled material is assembled into a core ingot (plate-shaped slab); a soaking process in which the rolled material and the core ingot are soaked; a hot rolling process in which the rolled material and the core ingot are rolled and bonded together to form the clad material; and a cold rolling process in which the clad material formed in the hot rolling process is thinned.

[0097] c-1.Soaking process In the soaking treatment step, the rolled material and the plate-shaped slab were stacked on top of each other after the assembling step, and the rolled material and the plate-shaped slab were held at a temperature of 480° C. for 3 hours.

[0098] c-2. Hot rolling process The hot rolling step is carried out at a temperature between 400°C and 500°C for 5 minutes or more.

[0099] c-3. Cold rolling process In the cold rolling process, the reduction rate per pass for plate thicknesses of 0.5 mm or more is 25% or more. Then, final annealing is performed at 360°C for 3 hours to give the brazing sheet an O temper with a plate thickness of 1 mm.

[0100] The casting temperature, casting cooling rate, homogenization temperature, equivalent strain in hot rolling of the rolled material, rolling time in the clad material manufacturing process, and reduction rate per cold rolling pass of the clad material for each manufacturing method are shown in Table 2. Note that for manufacturing methods A to G, the casting temperature, casting cooling rate, homogenization temperature, equivalent strain in hot rolling of the rolled material, rolling time in the clad material manufacturing process, and reduction rate per cold rolling pass of the clad material are controlled within the above-mentioned ranges, while for manufacturing methods H to N, any of the casting temperature, casting cooling rate, homogenization temperature, equivalent strain in hot rolling of the rolled material, rolling time in the clad material manufacturing process, and reduction rate per cold rolling pass of the clad material are outside the above-mentioned ranges.

[0101] [Table 2]

[0102] Single-sided clad brazing sheets were produced using the material (any of materials 1 to 6, 29 to 38) and manufacturing conditions (any of manufacturing methods A to N) to produce samples 1 to 6, 29 to 38, 45 to 57. The chemical compounds of each of samples 1 to 6, 29 to 38, 45 to 57 before heat treatment equivalent to brazing was measured, and heat treatment equivalent to brazing was performed on each of samples 1 to 6, 29 to 38, 45 to 57, and the erosion resistance of samples 1 to 6, 29 to 38, 45 to 57 was evaluated.

[0103] [Number of compounds (distribution)] B. Coarse intermetallic compounds The surface layers of samples 1-6, 29-38, and 45-57 were polished with abrasive grains of approximately 0.1 μm, and a fully automatic particle analysis of the brazing material was performed from the surface direction using an EPMA (electron probe microanalyzer). Furthermore, a thin film was prepared by mechanically polishing and electrolytically polishing the sample pieces cut out from the brazing material that constitutes the surface layer, and a 10,000 μm RD-TD parallel plane was observed using a TEM (transmission electron microscope). 2 The observation field was a 100 μm square, and coarse compounds were measured. In the case of a brazing filler metal for a V-surface brazing sheet, coarse compounds were those with a circle-equivalent diameter exceeding 10.00 μm and containing V. In the case of a Ti-surface brazing filler metal for a Ti-surface brazing sheet, coarse compounds were those with a circle-equivalent diameter exceeding 10.00 μm and containing Ti.

[0104] B. Fine intermetallic compounds Samples 1 to 6, 29 to 38, and 45 to 57 were etched to expose the central part of the plate thickness, and then polished with abrasive grains of approximately 0.1 μm. Fully automatic particle analysis of the core material was performed from the surface direction using an EPMA (electron probe microanalyzer). Sample pieces cut from the central part of the plate thickness were mechanically polished and electrolytically polished to prepare thin films, and a 10,000 μm RD-TD parallel plane was observed using a TEM (transmission electron microscope). 2The fine compounds in the core material were measured using an observation field of 100 μm square. For the core material of a V-surface-containing brazing sheet, the fine compounds were those with a circle-equivalent diameter of 0.01 μm to 5.00 μm and containing V. For the core material of a Ti-surface-containing brazing sheet, the fine compounds were those with a circle-equivalent diameter of 0.01 μm to 5.00 μm and containing Ti. Table 3 shows the number of coarse compounds in the brazing filler metal and the number of fine compounds in the core material.

[0105] [Erosion resistance] Samples 1 to 6, 29 to 38, and 45 to 57 were cut into test pieces measuring 60 mm in length and 25 mm in width, and then subjected to a heat treatment equivalent to brazing while hanging the test pieces in a heating furnace with the long sides parallel to the direction of gravity. The conditions for the heat treatment equivalent to brazing were to heat the test pieces to 600°C at an average heating rate of 100°C / min, hold at 600°C for 3 minutes, then cool to 150°C at a cooling rate of 100°C / min, and then air-cool to room temperature. The brazing filler pool formed at the bottom of the test piece after heat treatment equivalent to brazing is embedded in resin, and the cross section of the bottom of the test piece where the pool has formed is observed, and the thickness of the uneroded part of the test piece that remains uneroded by the molten brazing filler is measured. Here, the following equation (2) is defined as the erosion coefficient S. S = (thickness of core material before brazing - uneroded thickness after brazing) / thickness of core material before brazing (2) The "uneroded thickness after brazing" is the remaining thickness of the core material at the point where the brazing erosion is deepest. The erosion resistance was evaluated as follows: an erosion coefficient S of less than 1.8 was good; an erosion coefficient S of 1.8 or more but less than 2.4 was fair; and an erosion coefficient S of 2.4 or more was poor. Table 3 shows the evaluation of the erosion resistance of each sample, with "A" indicating good, "B" indicating fairly good, and "C" indicating poor.

[0106] [Table 3]

[0107] Samples 1 to 3 and 45 to 50 are surface V-containing brazing sheets. The brazing filler metal, core material, and clad material were manufactured from one of Materials 1 to 3, in which the brazing filler metal ingot contained 1.5 mass% to 14.0 mass% Si, 0.010 mass% to 1.5 mass% V, and the balance was Al and unavoidable impurities, and the core material ingot contained 0.010 mass% to 0.5 mass% Ti, and the balance was Al and unavoidable impurities, by controlling the manufacturing conditions of casting, homogenization, and rolling, using one of Manufacturing Methods A to G. As a result, the RD-TD parallel surface of the brazing material is 10,000 μm 2 In the observation field of the specimen, the distribution of coarse intermetallic compounds containing V with a diameter of 10.00 μm or more in equivalent circle diameter is controlled to less than 5 particles, and the RD-TD parallel plane of the core material is 10,000 μm. 2 In the observation field, 10 or more fine intermetallic compounds containing Ti and having a circle equivalent diameter of 0.01 μm or more and less than 5.00 μm are densely distributed. In erosion resistance tests, it was confirmed that by allowing the V in the molten filler metal to react sufficiently with the Ti in the core material to form a compound with a high melting point, erosion of the core material by the molten filler metal was reduced.

[0108] Samples 4 to 6 are surface Ti-containing brazing sheets. The brazing filler metal ingot contained 1.5 to 14.0 mass% Si, 0.010 to 1.5 mass% Ti, with the balance being Al and unavoidable impurities, and the core ingot contained 0.010 to 0.5 mass% V, with the balance being Al and unavoidable impurities. Materials 4 to 6 were manufactured into brazing filler metals, core materials, and clad materials by manufacturing method A, which controlled the manufacturing conditions for casting, homogenizing, and rolling. The brazing filler metal had a distribution of less than five coarse intermetallic compounds, while the core material had a dense distribution of 10 or more fine intermetallic compounds. In an erosion resistance test, it was confirmed that the Ti in the molten brazing filler metal and the V in the core material reacted sufficiently to form a high-melting-point compound, thereby reducing erosion of the core material by the molten brazing filler metal.

[0109] Sample 31 is a surface V-containing brazing sheet, and as an ingot for brazing filler metal, the Si content satisfies the requirement of 1.5 mass% or more and 14.0 mass% or less, but the V content is 0.005 mass% which is outside the range of 0.010 mass% or more and 0.5 mass% or less. The ingot for the core material contains V of 0.010 mass% or more and 0.5 mass% or less, with the remainder being Al and unavoidable impurities. Using material 31, brazing filler metal, core material, and clad material were manufactured by manufacturing method A, in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled. In the erosion resistance test of Sample 31, when the V content of the brazing filler metal was low, sufficient reaction between the V in the molten brazing filler metal and the Ti in the core metal was not achieved, and erosion could not be reduced. Sample 33 is a surface V-containing brazing sheet, and the ingot for the brazing filler metal contains 1.5 mass% or more and 14.0 mass% or less of Si, 0.010 mass% or more and 1.5 mass% or less of Ti, with the remainder consisting of Al and unavoidable impurities. The ingot for the core material has a Ti content of 0.005 mass%, which is outside the range of 0.010 mass% or more and 0.5 mass% or less. Using material 33, the brazing filler metal, core material, and clad material were manufactured by manufacturing method A, in which the manufacturing conditions for casting, homogenization treatment, and rolling were controlled. In the erosion resistance test of Sample 33, when the Ti content of the core material was low, sufficient reaction between the V in the molten brazing filler metal and the Ti in the core material was not achieved, and erosion could not be reduced.

[0110] Sample 36 is a brazing sheet containing Ti on the surface. The brazing filler metal ingot contains Si of 1.5% by mass or more and 14.0% by mass or less, but the Ti content is outside the range of 0.010% by mass or more and 0.5% by mass or less, and the core material ingot contains V of 0.010% by mass or more and 0.5% by mass or less, with the remainder being Al and unavoidable impurities. Using material 36, brazing filler metal, core material, and clad material were manufactured by manufacturing method A, in which the manufacturing conditions of casting, homogenization treatment, and rolling were controlled. In erosion resistance tests, when the brazing filler metal contained a small amount of Ti, the Ti in the molten brazing filler metal did not react sufficiently with the V in the core material, and erosion could not be reduced.

[0111] Samples 51 to 57 are surface-V-containing brazing sheets. The brazing filler metal ingot contained 1.5 to 14.0 mass% Si, 0.010 to 1.5 mass% V, and the remainder was Al and unavoidable impurities. The core ingot contained 0.010 to 0.5 mass% Ti, and the remainder was Al and unavoidable impurities. Brazing filler metals, core materials, and clad materials were manufactured from Material 1 by one of manufacturing methods H to N, which did not control any of the manufacturing conditions of casting, homogenization, or rolling. It was confirmed that, unless any of the manufacturing conditions of casting, homogenization, or rolling was controlled, it was impossible to achieve a small distribution of coarse intermetallic compounds in the brazing filler metal, or a dense distribution of fine intermetallic compounds in the core material. Furthermore, erosion resistance tests showed that sufficient reaction between the V in the molten brazing filler metal and the Ti in the core material was not achieved, resulting in a failure to reduce erosion.

[0112] In addition, Sample 35 had poor erosion resistance because both the brazing filler metal and the core material contained V and neither contained Ti, and Sample 38 had poor erosion resistance because both the brazing filler metal and the core material contained Ti and neither contained V.

[0113] Furthermore, for samples 30, 32, 34, and 37, any of materials 30, 32, 34, and 37 could not be manufactured using manufacturing method A. This is shown as "Manufacturing NG" in Table 3. Furthermore, for sample 29, due to a lack of brazing filler metal, the erosion resistance was not evaluated and the brazing was evaluated as poor (shown as "Brazing NG" in Table 3). Note that for sample 29, the counts of coarse intermetallic compounds in the brazing filler metal and the counts of fine intermetallic compounds in the core material are omitted. [Example]

[0114] The tensile strength Rm of brazing sheets, which were clad with brazing material on one side and manufactured using different materials and under different manufacturing conditions, was evaluated.

[0115] (material) The brazing sheet is configured as either a V-surface-containing or Ti-surface-containing type, and in either case, the brazing filler metal contains 1.5 to 14.0% by mass of Si and 0.010 to 1.5% by mass of V or Ti, and the core metal contains 0.010 to 0.5% by mass of V or Ti. Hereinafter, the Si content in the brazing filler metal ingot (plate-shaped slab) for constructing this V-surface-containing or Ti-surface-containing brazing sheet is defined as 1.5 to 14.0% by mass, the V or Ti content is 0.010 to 1.5% by mass, and the V or Ti content is 0.010 to 0.5% by mass. Furthermore, the V or Ti content in the core ingot (plate-shaped slab) is defined as 0.010 to 0.5% by mass. The Si, V, or Ti content in the brazing filler metal ingot and the V or Ti content in the core ingot are collectively referred to as the essential content.

[0116] In materials 7 to 18 and 39 to 44, the ingot for the brazing material and the ingot for the core material contain the essential contents, and the ingot for the core material further contains Mn, Si, Fe, and Cu. Materials 19 to 21 and 25 to 27 include the ingot for the brazing material and the ingot for the core material, each containing the essential contents, and the ingot for the core material further contains Mn, Si, Fe, and Cu, and any one of Mg, Cr, Zr, and Sr. The materials 22, 24 include the brazing ingot and the core ingot containing the essential contents, with the brazing ingot further containing Zn and the core ingot further containing Mn, Si, Fe and Cu. The material 23 includes an ingot for brazing material and an ingot for core material each containing the essential contents, the ingot for brazing material further containing Zn, and the ingot for core material further containing Mn, Si, Fe, Cu and Zn.

[0117] In the core ingot, the Mn content is 0.10% by mass to 2.0% by mass, the Si content is 0.05% by mass to 1.5% by mass, the Fe content is 0.05% by mass to 1.0% by mass, and the Cu content is 0.010% by mass to 2.0% by mass. Materials 39 to 44 have at least one of the contents of Mn, Si, Fe, and Cu outside these content ranges. Furthermore, in the core ingot, the core has a Mg content of 0.01% by mass or more and 1.0% by mass or less, a Zn content of 0.01% by mass or more and 5.0% by mass or less, a Cr content of 0.01% by mass or more and 0.35% by mass or less, a Zr content of 0.01% by mass or more and 0.35% by mass or less, and a Sr content of 0.01% by mass or more and 1.0% by mass or less. The Zn content of the ingot for the brazing filler metal is set to 0.01 mass % or more and 5.0 mass % or less.

[0118] Furthermore, material 28 is intended to form a brazing sheet that does not fall into either the surface V-containing type or the surface Ti-containing type, and neither the brazing filler metal ingot nor the core material ingot contains V, and neither the brazing filler metal ingot nor the core material ingot contains Ti.

[0119] The compositions of each of Materials 7 to 44 are shown in Table 4. The remainder of each brazing filler metal ingot and core metal ingot, not shown in Table 4, is aluminum and unavoidable impurities.

[0120] [Table 4]

[0121] (Brazing sheet manufacturing method) The manufacturing method of the brazing sheet includes a rolled material manufacturing process for manufacturing a rolled material for the brazing material, and a clad material manufacturing process for rolling and bonding the rolled material and a plate-shaped slab for the core material to form a brazing sheet. The manufacturing method of the rolled material for the brazing material includes an ingot manufacturing process for manufacturing an ingot, a homogenizing process for homogenizing the ingot, a facing process for facing the ingot, a soaking process for soaking the faced ingot before processing it, and a hot rolling process for rolling the soaked ingot (plate-shaped slab). The plate-shaped slab for the core material was manufactured through homogenization and facing, similar to the plate-shaped slab of Example 1. The casting pouring temperature, casting cooling rate, homogenization treatment temperature, equivalent strain of the hot rolling of the rolled material, rolling time in the clad material manufacturing process, and reduction rate per pass of cold rolling of the clad material for each manufacturing method are as shown in Table 2. After the cold rolling process, final annealing was performed at 360°C for 3 hours to produce a brazing sheet with an O temper and a thickness of 1 mm.

[0122] Brazing sheets clad with brazing material on one side were produced using the material (any of materials 7 to 44) and manufacturing conditions (any of manufacturing methods A to N) to produce samples 7 to 28, 39 to 44, and 58 to 96, and the strength of each of samples 7 to 28, 39 to 44, and 58 to 96 was measured. Samples were cut out parallel to the rolling direction from each of Samples 7 to 28, 39 to 44, and 58 to 96 to prepare No. 13B test pieces according to the tensile testing method for metallic materials (JIS Z2241:2011), and the tensile strength Rm was measured. A tensile strength Rm of 150.0 MPa or more was judged as good, 120.0 MPa or more and less than 150.0 MPa was judged as fair or acceptable, and less than 120.0 MPa was judged as poor (failed). In Tables 5 and 6, the tensile strength Rm of each of Samples 7 to 28, 39 to 44, and 58 to 96 is represented by A for good, B for fair, and C for poor. Tables 5 and 6 also show measurements of the chemical compounds of each of Samples 7 to 28, 39 to 44, and 58 to 96 before the brazing-equivalent heat treatment performed in Example 1, and evaluations of erosion resistance after the brazing-equivalent heat treatment was performed on each of Samples 7 to 28, 39 to 44, and 58 to 96.

[0123] [Table 5]

[0124] [Table 6]

[0125] Samples 7 to 28 and 58 to 96 had good or fairly good tensile strength Rm. Of these, Samples 7 to 27, 58 to 63, 71 to 76, and 84 to 89 also had good or fairly good erosion resistance. Samples 64 to 70, 77 to 83, and 90 to 96 were produced by a method (any of H to N in Table 2) that did not control any of the casting, homogenization, and rolling, and therefore had poor erosion resistance. Sample 28 was produced by production method A, which controlled the casting, homogenization, and rolling, but in Material 28, neither the brazing filler metal ingot nor the core ingot contained V, and neither the brazing filler metal ingot nor the core ingot contained Ti, and therefore had poor erosion resistance. Samples 39 and 40 had poor tensile strength Rm. These were produced by production method A, which controlled casting, homogenization, and rolling. However, in material 39 of sample 39, the Mn content was not controlled within the range of 0.10 mass% to 2.0 mass%, and the Si content was not controlled within the range of 0.05 mass% to 1.5 mass%, and in material 40 of sample 40, the Cu content was not controlled within the range of 0.010 mass% to 2.0 mass%. The materials 39 and 40 of Samples 39 and 40 contained the essential content and therefore had good erosion resistance.

[0126] Furthermore, for Samples 41, 43, and 44, an attempt was made to manufacture any of Materials 41, 43, and 44 using Manufacturing Method A, but manufacturing was not possible. This is shown as "Manufacturing NG" in Table 5. Furthermore, Sample 42 was not manufactured due to the high cost, as the Fe content of the core material was less than 0.050 mass% (shown as "Cost NG" in Table 5).

Claims

1. A brazing sheet having a brazing material clad on at least one surface of a core material, The brazing filler metal contains 1.5 mass % or more and 14.0 mass % or less of Si, 0.010 mass % or more and 1.5 mass % or less of one of V and Ti, and the balance being Al and inevitable impurities, the core material contains 0.010% by mass or more and 0.5% by mass or less of the other of V and Ti, with the remainder being Al and unavoidable impurities; The RD-TD parallel plane of the brazing material is 10000 μm ２ In the observation field of The RD-TD parallel plane of the core material is 10,000 μm ２ a brazing sheet characterized in that, in an observation field of the above, there are 10 or more intermetallic compounds each having a circle-equivalent diameter of 0.01 μm or more and less than 5.00 μm and containing the other metal;

2. 2. The brazing sheet according to claim 1, wherein the core material further contains any one of the following additional elements 1 to 4 or any combination of multiple elements. Additional element 1: Mn, Si, Fe, and Cu, in which the Mn content is 0.10 mass% or more and 2.0 mass% or less, the Si content is 0.05 mass% or more and 1.5 mass% or less, the Fe content is 0.05 mass% or more and 1.0 mass% or less, and the Cu content is 0.010 mass% or more and 2.0 mass% or less. Additional element 2: Mg, and the Mg content is 0.01 mass % or more and 1.0 mass % or less. Additional element 3: Zn, and the Zn content is 0.01 mass % or more and 5.0 mass % or less. Additional element 4: Any one or any combination of Cr, Zr, and Sr, wherein the Cr content is 0.01 mass% or more and 0.35 mass% or less, the Zr content is 0.01 mass% or more and 0.35 mass% or less, and the Sr content is 0.01 mass% or more and 1.0 mass% or less.

3. 3. The brazing sheet according to claim 1, wherein the brazing filler metal further contains Zn in an amount of 0.01 mass % to 5.0 mass %.

4. 3. The brazing sheet according to claim 1, wherein the other surface is formed of a sacrificial material.

5. 3. The brazing sheet according to claim 1, wherein the brazing filler metal further contains Zn in an amount of 0.01 mass % to 5.0 mass % both inclusive, and the other surface is formed of a sacrificial material.

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