Aluminum alloy and aluminum alloy brazing sheets

Abstract

To provide aluminum alloys and aluminum alloy brazing sheets with high thermal conductivity and strength. [Solution] An aluminum alloy is used, characterized in that its chemical composition contains, by mass%, Si: 0.03~1.00%, Fe: 0.20~1.20%, Sc: 0.01~0.30%, with the remainder being Al and unavoidable impurities, and the mass ratio of Sc to Si, Sc / Si, is 0.02~4.00, as well as an aluminum alloy brazing sheet having this aluminum alloy as the core material.

Description

[Technical Field]

[0001] This disclosure relates to aluminum alloys and aluminum alloy brazing sheets. [Background technology]

[0002] In recent years, motor-powered vehicles such as HEVs (hybrid electric vehicles), BEVs (battery electric vehicles), PHEVs (plug-in hybrid electric vehicles), and FCVs (fuel cell vehicles) have emerged, and their development and practical application are progressing. Unlike conventional gasoline-powered vehicles, these vehicles are equipped with new heat exchangers such as battery coolers, inverter coolers, and chillers. Due to their structure, battery coolers and inverter coolers have surface-to-surface contact with the battery, so the materials used for the heat exchangers must have high thermal conductivity.

[0003] Among common types of aluminum, pure aluminum, which does not contain additive elements, has high thermal conductivity. Therefore, to improve the thermal conductivity of a heat exchanger, it is sufficient to use pure aluminum. However, since heat exchangers for automobiles also require durability and vibration resistance, aluminum alloys, which have been strengthened by adding manganese (Mn) to aluminum, are generally used.

[0004] On the other hand, since Mn is an element that significantly reduces the thermal conductivity of aluminum, it is difficult to achieve high thermal conductivity in aluminum alloys even when Mn is added.

[0005] For example, Patent Document 1 discloses an aluminum alloy with excellent heat resistance, characterized by having a microstructure that satisfies at least one of the following (a) and (b). (a) The Al-Zr dispersed particles have a size of 35 to 450 angstroms and a spacing of 0.005 to 0.6 μm. (b) The Al-Sc dispersed particles have a size of 35–450 angstroms and a spacing of 0.005–0.6 μm.

[0006] Patent Document 2 discloses a high-strength aluminum alloy sheet material for heat exchangers with excellent erosion resistance, which is constructed by applying a powder brazing agent or a brazing agent composition containing a powder brazing agent to one or both of the surfaces of an aluminum alloy sheet.

[0007] Patent Document 3 discloses a high-strength aluminum alloy clad material for heat exchangers that has excellent erosion resistance, comprising an aluminum alloy core material with a sacrificial anode skin material bonded to one side and a brazing material made of an Al-Si alloy or Al-Si-Zn alloy bonded to the other side.

[0008] Patent Document 4 describes the properties of an aluminum alloy material before brazing as having a fibrous structure of 90% or more or 10% or less, an electrical conductivity in the range of 43-53% (IACS), and a dispersion of 3 × 10⁻¹⁶ particles with an equivalent circular diameter of 0.1-5 μm on the surface of the aluminum alloy material. 2 ~5×10 4 pieces / mm 2 In addition, the aluminum alloy material properties after brazing are such that the microstructure is in a recrystallized state, the crystal grain size of the recrystallized structure is 300 μm or more, the electrical conductivity is in the range of 45-55% (IACS), and the dispersed particles on the surface of the aluminum alloy material with an equivalent circular diameter of 0.1-5 μm are 3 × 10⁻¹⁶. 3 ~5×10 5 pieces / mm 2 Disclosed is a high-strength aluminum alloy material for automotive heat exchanger fins, which is manufactured by brazing and has excellent formability and erosion resistance, and is characterized by being within the range of [specified range]. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 9-95750 [Patent Document 2] Japanese Patent Publication No. 2006-176851 [Patent Document 3] Japanese Patent Publication No. 2006-176852 [Patent Document 4] Patent No. 5186185 [Overview of the project] [Problems that the invention aims to solve]

[0010] This disclosure is made in view of the above circumstances and aims to provide an aluminum alloy and an aluminum alloy brazing sheet having high thermal conductivity and strength. [Means for solving the problem]

[0011] The gist of this disclosure is as follows: [1] The chemical composition is, in mass%, Si: 0.03~1.00%, Fe: 0.20~1.20%, Contains Sc: 0.01~0.30%, The remainder consists of Al and unavoidable impurities. An aluminum alloy characterized in that the mass ratio of Sc to Si, which is Sc / Si, is 0.02 to 4.00. [2] The average equivalent circle diameter of Al-Si-Sc intermetallic compounds is 0.10 to 1.20 μm. The number density of the aforementioned Al-Si-Sc intermetallic compound is 1,000 to 20,000 particles / mm³ 2 The aluminum alloy described in [1] is characterized by being the same as the aluminum alloy described in [1]. [3] The tensile strength is 100 to 150 MPa, The aluminum alloy according to [1] or [2], characterized in that it has an electrical conductivity of 40% IACS or higher. [4] Brazing heat treatment in which the temperature range is 575~630℃ and held for more than 0 minutes and 20 minutes or less, After undergoing aging heat treatment, which involves holding the material at a temperature range of 150-450°C for 0-4 hours, The 0.2% yield strength is 40 MPa or higher. The aluminum alloy according to any one of [1] to [3], characterized in that its electrical conductivity is 40% IACS or more. [5] The chemical composition is, in mass%, Cu: more than 0.00% and at most 0.90%, Mn: more than 0.00% and at most 0.30%, Cr: more than 0.00% and at most 0.30%, Zn: more than 0.00% and at most 1.00%, Ti: more than 0.00% and at most 0.30%, Ni: more than 0.00% and at most 0.30%, Zr: more than 0.00% and at most 0.30%, V: more than 0.00% and at most 0.30%, and Mg: more than 0.00% and at most 1.00%, and further contains one or more of the above, characterized in that it is the aluminum alloy according to any one of [1] to [4]. [6] A core material, and A brazing material disposed on one or both sides of the core material, and The core material is The chemical composition is, in mass%, Si: 0.03 to 1.00%, Fe: 0.20 to 1.20%, Sc: contains 0.01 to 0.30%, The balance consists of Al and inevitable impurities, The aluminum alloy brazing sheet, characterized in that the mass ratio of Sc / Si, which is the mass ratio of Sc to Si, is 0.02 to 4.00. [7] The core material is The average value of the equivalent circle diameter of the Al-Si-Sc-based intermetallic compound is 0.10 to 1.20 μm, The number density of the Al-Si-Sc-based intermetallic compound is 1000 to 20000 pieces / mm 2 The aluminum alloy brazing sheet according to [6], characterized in that it is so. [8] The tensile strength is 100 to 150 MPa, The aluminum alloy brazing sheet according to [6] or [7], characterized in that its electrical conductivity is 40% IACS or more. <00001[9] Brazing heat treatment in which the temperature range is 575~630℃ and held for more than 0 minutes and 20 minutes or less, After undergoing aging heat treatment, which involves holding the material at a temperature range of 150-450°C for 0-4 hours, The 0.2% yield strength is 40 MPa or higher. An aluminum alloy brazing sheet according to any one of the following [6] to [8], characterized in that it has an electrical conductivity of 40% IACS or higher.

[10] The chemical composition of the core material is, in mass%, Cu: more than 0.00%, less than 0.90%, Mn: more than 0.00%, less than 0.30%, Cr: more than 0.00%, less than 0.30%, Zn: more than 0.00%, less than 1.00%, Ti: more than 0.00%, less than 0.30%, Ni: more than 0.00%, less than 0.30%, Zr: more than 0.00%, less than 0.30%, V: more than 0.00%, less than 0.30%, and An aluminum alloy brazing sheet according to any one of the following [6] to [9], characterized in that it further contains one or more Mg in an amount greater than 0.00% and 1.00% or less.

[11] The chemical composition of the brazing material is, in mass%, It contains Si: 3.00~13.00%, Optional, Zn: 0.10~6.00%, and Mg: Contains one or more elements in an amount of 0.10-3.00%, The aluminum alloy brazing sheet according to any one of [6] to

[10] , characterized in that the remainder consists of Al and unavoidable impurities. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide aluminum alloys and aluminum alloy brazing sheets having high thermal conductivity and strength. [Modes for carrying out the invention]

[0013] The inventors investigated aluminum alloys that possess high thermal conductivity while maintaining the strength required for automotive heat exchangers, and obtained the following findings. The aluminum alloy has a chemical composition in which, by mass%, Si: 0.03~1.00%, Fe: 0.20~1.20%, and Sc: 0.01~0.30%, with the remainder being Al and unavoidable impurities, and the mass ratio of Sc to Si, Sc / Si, is 0.02~4.00. This allows it to have high thermal conductivity while maintaining the strength required for automotive heat exchangers.

[0014] The aluminum alloys related to this disclosure will be described in detail below. Note that the numerical ranges indicated by "~" below include both the lower and upper limits. Numbers indicated as "less than" or "greater than" do not include the numerical range. All "%" figures for chemical composition represent "mass%".

[0015] Si: 0.03~1.00% Si is an element that enhances the strength of aluminum alloys through solid solution strengthening and by precipitation as Al-Fe-Si and / or Al-Si-Sc intermetallic compounds. If the Si content is less than 0.03%, the desired strength cannot be obtained in brazing heat treatment and aging heat treatment. Therefore, the Si content should be 0.03% or more. On the other hand, if the Si content exceeds 1.00%, the electrical conductivity of the aluminum alloy decreases. Furthermore, the melting point decreases, and localized melting occurs during brazing. Therefore, the Si content should be 1.00% or less.

[0016] Fe: 0.20~1.20% Fe is an element that enhances the strength of aluminum alloys by precipitating as Al-Fe and / or Al-Fe-Si intermetallic compounds. If the Fe content is less than 0.20%, the desired strength cannot be obtained in brazing heat treatment and aging heat treatment. Therefore, the Fe content should be 0.20% or more. Preferably, the Fe content is 0.30% or more. On the other hand, if the Fe content exceeds 1.20%, coarse intermetallic compounds are formed during casting, reducing rollability. Therefore, the Fe content should be 1.20% or less. Preferably, the Fe content is 1.10% or less.

[0017] Sc: 0.01~0.30% Sc (carbon dioxide) is an element that enhances the strength of aluminum alloys by precipitating as Al-Sc and / or Al-Si-Sc intermetallic compounds. If the Sc content is less than 0.01%, the desired strength cannot be obtained in brazing heat treatment and aging heat treatment. Therefore, the Sc content should be 0.01% or more. On the other hand, if the Sc content exceeds 0.30%, coarse intermetallic compounds are formed during casting, reducing rollability. Furthermore, the high cost of the base alloy increases manufacturing costs. Therefore, the Sc content should be kept below 0.30%.

[0018] Sc / Si: 0.02~4.00 If the mass ratio of Sc to Si, Sc(mass%) / Si(mass%), is less than 0.02%, sufficient Al-Sc and / or Al-Si-Sc intermetallic compounds necessary for ensuring strength cannot be deposited, and the desired strength cannot be obtained in brazing heat treatment and aging heat treatment. Therefore, Sc / Si should be 0.02 or higher. Preferably, Sc / Si is 0.05 or higher, 0.10 or higher, or 0.15 or higher. On the other hand, if the Sc / Si ratio exceeds 4.00, the electrical conductivity of the aluminum alloy decreases. Therefore, the Sc / Si ratio should be 4.00 or less. Preferably, the Sc / Si ratio is 3.50 or less, 3.00 or less, 2.50 or less, or 2.00 or less.

[0019] The remainder of the chemical composition of the aluminum alloy consists of Al and unavoidable impurities. In this disclosure, unavoidable impurities refer to elements that are inevitably mixed in during the manufacture of the aluminum alloy. Unavoidable impurities may be present in an amount that does not affect the properties of the aluminum alloy foil relating to this disclosure.

[0020] The aluminum alloy relating to this disclosure may contain one or more of the following optional elements in place of a portion of the remaining Al. Since the following optional elements are not required, the lower limit is 0%.

[0021] Cu: more than 0.00%, less than 0.90% Cu is an element that increases the strength of aluminum alloys through solid solution strengthening. From the viewpoint of further increasing strength, Cu may be included. To ensure the effect of strength improvement, it is preferable that the Cu content be 0.10% or more. On the other hand, if the Cu content exceeds 0.90%, the electrical conductivity of the aluminum alloy decreases. Furthermore, the melting point decreases, and localized melting occurs during brazing. Therefore, it is preferable to keep the Cu content at 0.90% or less.

[0022] Mn: more than 0.00%, less than 0.30% Mn is an element that increases the strength of aluminum alloys through solid solution strengthening and by precipitation as an intermetallic compound. From the viewpoint of further increasing strength, Mn may be included. On the other hand, if the Mn content exceeds 0.30%, the electrical conductivity decreases. Therefore, it is preferable to keep the Mn content at 0.30% or less.

[0023] Cr: more than 0.00%, less than 0.30% Cr is an element that increases the strength of aluminum alloys through solid solution strengthening and by precipitation as an intermetallic compound. From the viewpoint of further increasing strength, Cr may be included. On the other hand, if the Cr content exceeds 0.30%, the electrical conductivity decreases. Furthermore, coarse intermetallic compounds are formed during casting, reducing rollability. Therefore, it is preferable to keep the Cr content below 0.30%.

[0024] Zn: more than 0.00%, less than 1.00% Zinc is an element that can be present when scrap materials are generated during the production of aluminum alloy brazing sheets, or when aluminum alloy brazing sheets that have been used in the market are reused as core material. When these recycled materials are used, they may contain Zn. On the other hand, if the Zn content exceeds 1.00%, the electrical conductivity and corrosion resistance of the aluminum alloy decrease. Therefore, it is preferable to keep the Zn content at 1.00% or less.

[0025] Ti: more than 0.00%, less than 0.30% Ti is an element that increases the strength of aluminum alloys through solid solution strengthening and by precipitation as an intermetallic compound. From the viewpoint of further increasing strength, Ti may be included. On the other hand, if the Ti content exceeds 0.30%, the electrical conductivity decreases. Furthermore, coarse intermetallic compounds are formed during casting, reducing rollability. Therefore, it is preferable to keep the Ti content below 0.30%.

[0026] Ni: more than 0.00%, less than 0.30% Ni is an element that increases the strength of aluminum alloys through solid solution strengthening and by precipitation as an intermetallic compound. Ni may be included to further enhance strength. On the other hand, if the Ni content exceeds 0.30%, the electrical conductivity decreases. Furthermore, coarse intermetallic compounds are formed during casting, reducing rollability. Therefore, it is preferable to keep the Ni content below 0.30%.

[0027] Zr: more than 0.00%, less than 0.30% Zr is an element that increases the strength of aluminum alloys through solid solution strengthening and by precipitation as an intermetallic compound. From the viewpoint of further increasing strength, Zr may be included. On the other hand, if the Zr content exceeds 0.30%, the electrical conductivity decreases. Furthermore, coarse intermetallic compounds are formed during casting, reducing rollability. Therefore, it is preferable to keep the Zr content below 0.30%.

[0028] V: Over 0.00% and below 0.30% V is an element that enhances the strength of aluminum alloys by solid solution strengthening and by precipitating as intermetallic compounds. From the perspective of further enhancing strength, V may be contained. On the other hand, when the V content exceeds 0.30%, the electrical conductivity decreases. Furthermore, coarse intermetallic compounds are generated during casting, and the rolling property deteriorates. Therefore, it is preferable that the V content be 0.30% or less.

[0029] Mg: Over 0.00% and below 1.00% Mg is an element that enhances the strength of aluminum alloys by solid solution strengthening and by age hardening. Furthermore, by containing Mg, fluxless brazing becomes possible. From these perspectives, Mg may be contained. On the other hand, when the Mg content exceeds 1.00%, the electrical conductivity decreases. Therefore, it is preferable that the Mg content be 1.00% or less.

[0030] Average value of the equivalent circle diameter of Al-Si-Sc-based intermetallic compounds: 0.10 - 1.20 μm Number density of Al-Si-Sc-based intermetallic compounds: 1000 - 20000 per mm 2 The aluminum alloy according to the present disclosure has an average value of the equivalent circle diameter of Al-Si-Sc-based intermetallic compounds of 0.10 - 1.20 μm, and a number density of Al-Si-Sc-based intermetallic compounds of 1000 - 20000 per mm 2 is preferable. By preferably controlling the average value of the equivalent circle diameter and the number density of Al-Si-Sc-based intermetallic compounds, the strength of the aluminum alloy can be further enhanced.

[0031] The average value of the equivalent circle diameter and the number density of Al-Si-Sc-based intermetallic compounds are obtained by the following method. For aluminum alloys, the cross-section of the plate thickness parallel to the rolling direction is processed using a cross-section polisher (registered trademark) manufactured by JEOL Ltd. Ten secondary electron images are acquired from the processed cross-section using a field emission scanning electron microscope (FE-SEM: JEOL Ltd. JSM-7900F) at a magnification of 10,000x and an acceleration voltage of 15kV. The equivalent circular diameter and number density of Al-Si-Sc intermetallic compounds are calculated from the acquired images. Furthermore, elemental analysis of intermetallic compounds in the acquired images is performed using the EDS attached to the FE-SEM, and intermetallic compounds in which Si is detected at 1.0 wt% or more and Sc is detected at 0.3 wt% or more are identified as Al-Si-Sc intermetallic compounds.

[0032] Tensile strength: 100-150 MPa The tensile strength is preferably 100 to 150 MPa. If the tensile strength is 100 MPa or higher, it can be used for automotive heat exchangers. If the tensile strength is 150 MPa or lower, automotive heat exchangers can be molded without processing defects during molding.

[0033] Tensile strength is obtained by the following method. For the tensile test, a JIS No. 5 test specimen is taken from the aluminum alloy in accordance with JIS Z 2241:2022, along the rolling direction. The collected test specimen is subjected to a tensile test using a universal tensile testing machine (Shimadzu AGS-X 100kN) at a tensile speed of 3 to 10 mm / min. The tensile strength is determined by the maximum stress. The tensile test is performed three times, and the tensile strength is obtained by calculating the average value of these tests.

[0034] Electrical conductivity: 40% IACS or higher The electrical conductivity is preferably 40% IACS or higher. If the electrical conductivity is 40% IACS or higher, it can be judged to have excellent electrical conductivity. There is no particular upper limit to the electrical conductivity, but for example, it may be 65% IACS or lower. Here, electrical conductivity and thermal conductivity are proportional, and if electrical conductivity is high, it can be determined that thermal conductivity is also high. In this disclosure, electrical conductivity, which is proportional to thermal conductivity, is evaluated as an indicator of thermal conductivity.

[0035] Electrical conductivity is obtained by measuring it at room temperature using an eddy current conductivity meter, in accordance with the conductivity measurement method of JIS H 0505:2024.

[0036] (After brazing heat treatment and aging heat treatment) 0.2% yield strength: 40MPa or more Electrical conductivity: 40% IACS or higher If, after brazing heat treatment and aging heat treatment, the 0.2% proof stress is 40 MPa or higher and the electrical conductivity is 40% IACS or higher, then high electrical conductivity and strength can be achieved even when used as a heat exchanger for automobiles. In this disclosure, the brazing heat treatment is defined as a heat treatment held at a temperature range of 575 to 630°C for more than 0 minutes and 20 minutes or less, and the aging heat treatment is defined as a heat treatment held at a temperature range of 150 to 450°C for 0 to 4 hours. The aging heat treatment may or may not be performed after the brazing heat treatment, but performing the aging heat treatment can further increase the electrical conductivity and strength. In this disclosure, it is preferable that the 0.2% proof stress and electrical conductivity are within the above range whether or not the aging heat treatment is performed, or whether or not the aging heat treatment is performed under the above conditions.

[0037] The 0.2% yield strength of aluminum alloys after brazing heat treatment and aging heat treatment is obtained by performing a tensile test using the method described above. The method for measuring the electrical conductivity of aluminum alloys after brazing heat treatment and aging heat treatment is the same as described above, so the explanation is omitted.

[0038] Next, we will describe the aluminum alloy brazing sheet related to this disclosure. The aluminum alloy brazing sheet according to this disclosure comprises a core material and brazing material disposed on one or both sides of the core material. The aluminum alloy brazing sheet may have a three-layer structure in which brazing material made of aluminum alloy is clad as a cladding layer on both sides of the core material made of aluminum alloy, or it may have a two-layer structure in which the brazing material is disposed on only one side of the core material. Furthermore, the aluminum alloy brazing sheet may have a multi-layer structure for the brazing material. For example, it may have a structure in which one or more additional layers of brazing material are provided between the core material and the brazing material, or a multi-layer structure in which one or more additional layers such as sacrificial material are provided between the core material and the brazing material. Alternatively, it may have a three-layer structure in which brazing material is placed on one side of the core material and sacrificial material is provided on the opposite side.

[0039] The aluminum alloy described above is used as the core material for the aluminum alloy brazing sheet. Since the aluminum alloy brazing sheet core material has the same chemical composition and structure as the aluminum alloy described above, their explanation will be omitted. When measuring the microstructure of the core material of an aluminum alloy brazing sheet, the measurement should be taken at the cross-sectional area of ​​the aluminum alloy brazing sheet at its thickness.

[0040] The aluminum alloy brazing sheet according to this disclosure preferably has a tensile strength of 100 to 150 MPa and an electrical conductivity of 40% IACS or higher. If the tensile strength is 100 MPa or higher, it can be used for automotive heat exchangers. Furthermore, if the tensile strength is 150 MPa or lower, automotive heat exchangers can be molded without processing defects during molding. Additionally, if the electrical conductivity is 40% IACS or higher, it can be considered to have excellent electrical conductivity. There is no particular upper limit to the electrical conductivity, but for example, it may be 65% IACS or lower. The methods for measuring tensile strength and electrical conductivity are the same as for aluminum alloys, so the explanation will be omitted.

[0041] The aluminum alloy brazing sheet according to this disclosure preferably has a 0.2% proof stress of 40 MPa or more and an electrical conductivity of 40% IACS or more after undergoing brazing heat treatment held at a temperature range of 575 to 630°C for more than 0 minutes and 20 minutes or less, and aging heat treatment held at a temperature range of 150 to 450°C for 0 to 4 hours. If the 0.2% proof stress is 40 MPa or more and the electrical conductivity is 40% IACS or more after brazing heat treatment and aging heat treatment, it can exhibit high electrical conductivity and strength even when used as a heat exchanger for automobiles. The 0.2% yield strength of the aluminum alloy brazed sheet after brazing heat treatment and aging heat treatment is obtained by the same method as for the aluminum alloy. The method for measuring the electrical conductivity of an aluminum alloy brazing sheet after brazing heat treatment and aging heat treatment is the same as for aluminum alloys.

[0042] The brazing material for aluminum alloy brazing sheets is an Al-Si aluminum alloy, and its chemical composition preferably contains 3.00 to 13.00% Si by mass, and optionally contains one or more of 0.10 to 6.00% Zn and 0.10 to 3.00% Mg. Zn and Mg may be omitted.

[0043] Si: 3.00~13.00% Si is an element included to lower the melting point of Al, allowing it to melt during brazing and bond with other components. If the Si content is less than 3.00%, sufficient molten solder may not be obtained, potentially resulting in brazing defects. Therefore, it is preferable to have a Si content of 3.00% or more. On the other hand, if the Si content exceeds 13.00%, the core material may melt, making it impossible to maintain the shape of the heat exchanger. Furthermore, the increased amount of molten solder can lead to solder being supplied to areas beyond what is necessary, potentially causing clogging in the heat exchanger. Therefore, it is preferable to keep the Si content below 13.00%.

[0044] The remainder of the chemical composition of the brazing material consists of Al and unavoidable impurities. A portion of the remaining Al may be replaced with one or more of the following optional elements. Since the following optional elements are not required, their lower limit is 0%.

[0045] Zn: 0.10~6.00% Zn is an element that lowers the potential of the brazing material and protects the core material from corrosion through sacrificial anode action. To reliably obtain this effect, it is preferable that the Zn content be 0.10% or more. On the other hand, if the Zn content exceeds 6.00%, the corrosion rate increases, and the brazing material corrodes prematurely, making it impossible to obtain the desired corrosion resistance for an aluminum alloy brazing sheet. Therefore, it is preferable to keep the Zn content at 6.00% or less.

[0046] Mg: 0.10~3.00% The inclusion of magnesium (Mg) enables fluxless brazing. To improve brazing performance, it is preferable that the Mg content be 0.10% or higher. On the other hand, if the Mg content exceeds 3.00%, the electrical conductivity decreases. Furthermore, the amount of MgO generated on the surface increases, inhibiting brazing properties. Therefore, it is preferable to keep the Mg content at 3.00% or less.

[0047] In addition to the elements mentioned above, the brazing material may further contain 0.80% by mass or less of Fe.

[0048] Next, a preferred manufacturing method for producing the aluminum alloy relating to this disclosure will be described. A preferred method for producing an aluminum alloy according to this disclosure involves casting, homogenization, hot rolling, cold rolling, and annealing.

[0049] casting The casting method is not particularly limited; for example, aluminum alloys may be cast using a semi-continuous casting method.

[0050] Homogenization treatment It is preferable to perform a homogenization treatment on the cast aluminum alloy by holding it at a temperature range of 500°C or higher and less than 630°C for 2 hours or more and less than 15 hours. By performing the homogenization treatment under these conditions, high thermal conductivity and strength can be obtained in the aluminum alloy. If the holding temperature is 630°C or higher, or the holding time exceeds 15 hours, the aluminum alloy will partially melt during the homogenization process and will not be able to maintain its shape. The holding temperature is preferably 520°C or higher and 600°C or lower.

[0051] Hot rolling In hot rolling, it is preferable to set the finishing temperature (the exit temperature at the final stage) to 280°C or higher in order to obtain the desired properties. More preferably, the finishing temperature is 350°C or higher.

[0052] cold rolling While there are no particular limitations on the cold rolling conditions, it is preferable to perform cold rolling under conditions where the reduction ratio per pass is 20-50% from the viewpoint of ensuring manufacturability.

[0053] Annealing In annealing, it is preferable to set the average heating rate to 30-70°C / h and hold the material in the temperature range of 300-430°C for 1-10 hours. Holding the material at a temperature of 300°C or higher during annealing allows for complete recrystallization, while holding it at 430°C or lower suppresses secondary recrystallization of the core material, resulting in uniform recrystallized grains.

[0054] The aluminum alloy relating to this disclosure can be stably manufactured by the method described above. The brazing material can be manufactured, for example, by obtaining an ingot through semi-continuous casting, followed by homogenization and hot rolling. In the homogenization process of the brazing material, it is preferable to hold it at a temperature range of 400 to 550°C for 1 to 10 hours in order to improve machinability.

[0055] The aluminum alloy brazing sheet relating to this disclosure can be manufactured by bonding an aluminum alloy (core material) produced by the method described above with a brazing material, hot rolling (clad rolling), cold rolling, and annealing.

[0056] bonding The aluminum alloy (core material) manufactured using the method described above is combined with a sheet-shaped brazing material. The cladding ratio when bonding should be set within the range of brazing material:core material = 5-20%:80-95%.

[0057] Hot rolling The core material and the brazing material are bonded together and then hot-rolled (clad-rolled) using a hot-rolling mill. In hot-rolling, it is preferable to set the finished temperature (the exit temperature at the final stage) to 280°C or higher in order to obtain the desired properties. More preferably, the finished temperature is 350°C or higher.

[0058] cold rolling While there are no particular limitations on the cold rolling conditions, it is preferable to perform cold rolling under conditions where the reduction ratio per pass is 20-50% from the viewpoint of ensuring manufacturability.

[0059] Annealing It is preferable to perform annealing to recrystallize the core material and brazing material. In annealing, it is preferable to have an average heating rate of 30 to 70°C / h and to hold the material in the temperature range of 300 to 430°C for 1 to 10 hours. By holding the material at a temperature of 300°C or higher during annealing, recrystallization can be completed, and by keeping the temperature below 430°C, secondary recrystallization of the core material's structure can be suppressed, resulting in uniform recrystallized grains.

[0060] By the method described above, the aluminum alloy brazing sheet relating to this disclosure can be manufactured stably. [Examples]

[0061] Next, the effects of one aspect of this disclosure will be described in more detail by reference to examples. However, the conditions in the examples are merely examples of conditions adopted to confirm the feasibility and effectiveness of this disclosure, and this disclosure is not limited to these examples of conditions. This disclosure may adopt various conditions as long as they do not depart from the gist of this disclosure and achieve the objectives of this disclosure.

[0062] Aluminum alloys having the chemical compositions shown in Tables 1A to 1D were produced using a semi-continuous casting method and the HOMO (homogenization treatment) conditions (shown in Tables 2A to 2D) and hot rolling conditions (shown in Tables 2A to 2D). Cold rolling was performed under conditions where the reduction ratio per pass was 30%, and annealing was carried out at an average heating rate of 50°C / h, held at 360°C for 5 hours. The resulting aluminum alloy sheet had a thickness of 1 mm.

[0063] For the obtained aluminum alloy (core material), the average value and number density of the Al-Si-Sc intermetallic compound, tensile strength, electrical conductivity, and the 0.2% proof stress and electrical conductivity after brazing heat treatment and aging heat treatment were measured using the method described above. However, the brazing heat treatment was performed by raising the temperature from room temperature to 600°C, holding it for 5 minutes, and then cooling it to room temperature at an average cooling rate of 100°C / min. The aging heat treatment was performed by holding it at 300°C for 30 minutes. The results obtained are shown in Tables 2A to 2D. Underlined text in the table indicates that the information is outside the scope of this disclosure, that the manufacturing conditions are undesirable, or that the characteristic values ​​are undesirable.

[0064] If the tensile strength was between 100 and 150 MPa, it was judged to have high strength and was deemed acceptable. On the other hand, if the tensile strength was outside the above range, it was judged to not have high strength and was deemed unacceptable. If the electrical conductivity was 40% IACS or higher, it was judged to have high thermal conductivity and was deemed acceptable. On the other hand, if the electrical conductivity was less than 40% IACS, it was judged to have low thermal conductivity and was deemed unacceptable.

[0065] The 0.2% proof stress after brazing heat treatment and aging heat treatment was evaluated according to the following criteria. If the evaluation was "acceptable" or higher, i.e., the 0.2% proof stress was 40 MPa or higher, it was judged to be acceptable. 100MPa or more: Excellent (◎) 60 MPa or higher, less than 100 MPa: Good (○) 40 MPa or higher, less than 60 MPa: Possible (△) Less than 40 MPa: Not possible (×)

[0066] The electrical conductivity after brazing heat treatment and aging heat treatment was evaluated according to the following criteria. If the evaluation was "acceptable" or higher, i.e., if the electrical conductivity was 40% IACS or higher, it was judged as passing the test. 55%IACS or higher: Excellent (◎) 50% or higher, less than 55%: Good (○) 40% or more IACS, less than 50% IACS: Acceptable (△) Less than 40% IACS: Not acceptable (×)

[0067] Furthermore, brazing materials having the chemical composition shown in Table 3 were manufactured by a semi-casting method. The brazing materials were subjected to a homogenization treatment by holding them at 450°C for 1 hour, and then hot-rolled to the assembly thickness. The obtained brazing material and the aforementioned aluminum alloy (core material) (before brazing heat treatment and aging heat treatment) were bonded together in the combinations shown in Tables 4A to 4D, with a brazing material:core material ratio of 10%:90%. A 1 mm thick aluminum alloy brazing sheet was then manufactured by hot rolling (clad rolling), cold rolling, and annealing. Furthermore, cold rolling was performed under conditions where the reduction ratio per pass was 30%, followed by annealing at an average heating rate of 50°C / h and holding at 360°C for 5 hours.

[0068] For the core material of the obtained aluminum alloy brazing sheet, the average value and number density of the Al-Si-Sc intermetallic compound, tensile strength, electrical conductivity, and the 0.2% yield strength and electrical conductivity after brazing and aging heat treatment were measured using the method described above. The conditions for brazing and aging heat treatment were the same as those for the aluminum alloy. The results obtained are shown in Tables 4A to 4D. The evaluation criteria for tensile strength, electrical conductivity, and 0.2% yield strength and electrical conductivity after brazing heat treatment and aging heat treatment were the same as those for aluminum alloys.

[0069] Furthermore, in order to evaluate the effects of brazing heat treatment and aging heat treatment on aluminum alloys and aluminum alloy brazing sheets before brazing heat treatment and aging heat treatment, brazing heat treatment and aging heat treatment were performed under the conditions described in Tables 5A and 5B. The 0.2% yield strength and electrical conductivity of aluminum alloys and aluminum alloy brazing sheets after brazing heat treatment and aging heat treatment were measured using the method described above. The evaluation criteria were the same as those described above.

[0070] [Table 1A]

[0071] [Table 1B]

[0072] [Table 1C]

[0073] [Table 1D]

[0074] [Table 2A]

[0075] [Table 2B]

[0076] [Table 2C]

[0077] [Table 2D]

[0078] [Table 3]

[0079] [Table 4A]

[0080] [Table 4B]

[0081] [Table 4C]

[0082] [Table 4D]

[0083] [Table 5A]

[0084] [Table 5B]

[0085] As shown in Tables 1A to 5B, the aluminum alloy and aluminum alloy brazing sheet according to the examples exhibit high thermal conductivity and strength. On the other hand, the aluminum alloy and aluminum alloy brazing sheet according to the comparative examples show deterioration in one or more properties.

Claims

1. The chemical composition is expressed in mass percent. Si: 0.03-1.00%, Fe: 0.20-1.20%, Contains Sc: 0.01-0.30%, The remainder consists of Al and unavoidable impurities. An aluminum alloy characterized in that the mass ratio of Sc to Si, which is Sc / Si, is 0.02 to 4.

00.

2. The average equivalent circle diameter of Al-Si-Sc intermetallic compounds is 0.10 to 1.20 μm. The number density of the Al-Si-Sc intermetallic compound is 1,000 to 20,000 particles / mm². ２ The aluminum alloy according to claim 1, characterized in that it is the same as described in claim 1.

3. The tensile strength is 100 to 150 MPa. The aluminum alloy according to claim 1, characterized in that its electrical conductivity is 40% IACS or higher.

4. The tensile strength is 100 to 150 MPa. The aluminum alloy according to claim 2, characterized in that its electrical conductivity is 40% IACS or higher.

5. Brazing heat treatment, in which the temperature range is 575 to 630°C and held for more than 0 minutes and 20 minutes or less, and After aging heat treatment, which involves holding the material at a temperature range of 150 to 450°C for 0 to 4 hours, The 0.2% proof stress is 40 MPa or higher. An aluminum alloy according to any one of claims 1 to 4, characterized in that its electrical conductivity is 40% IACS or higher.

6. The aforementioned chemical composition is, in mass%, Cu: more than 0.00%, 0.90% or less, Mn: more than 0.00%, less than 0.30%, Cr: more than 0.00%, 0.30% or less, Zn: more than 0.00%, less than 1.00%, Ti: more than 0.00%, less than 0.30%, Ni: more than 0.00%, less than 0.30%, Zr: more than 0.00%, less than 0.30%, V: more than 0.00%, less than 0.30%, and The aluminum alloy according to any one of claims 1 to 4, further characterized by containing one or more Mg in an amount greater than 0.00% and less than or equal to 1.00%.

7. The aforementioned chemical composition is, in mass%, Cu: more than 0.00%, 0.90% or less, Mn: more than 0.00%, less than 0.30%, Cr: more than 0.00%, 0.30% or less, Zn: more than 0.00%, less than 1.00%, Ti: more than 0.00%, less than 0.30%, Ni: more than 0.00%, less than 0.30%, Zr: more than 0.00%, less than 0.30%, V: more than 0.00%, less than 0.30%, and The aluminum alloy according to claim 5, further characterized by containing one or more Mg in an amount greater than 0.00% and less than or equal to 1.00%.

8. The heartwood and, The core material comprises a brazing material arranged on one or both sides thereof, The aforementioned core material is The chemical composition is expressed in mass percent. Si: 0.03-1.00%, Fe: 0.20-1.20%, Contains Sc: 0.01-0.30%, The remainder consists of Al and unavoidable impurities. An aluminum alloy brazing sheet characterized in that the mass ratio of Sc to Si, which is Sc / Si, is 0.02 to 4.

00.

9. The aforementioned core material is The average equivalent circle diameter of Al-Si-Sc intermetallic compounds is 0.10 to 1.20 μm. The number density of the Al-Si-Sc intermetallic compound is 1,000 to 20,000 particles / mm². ２ The aluminum alloy brazing sheet according to claim 8, characterized in that it is the same as the aluminum alloy brazing sheet according to claim 8.

10. The tensile strength is 100 to 150 MPa. The aluminum alloy brazing sheet according to claim 8, characterized in that its electrical conductivity is 40% IACS or higher.

11. The tensile strength is 100 to 150 MPa. The aluminum alloy brazing sheet according to claim 9, characterized in that its electrical conductivity is 40% IACS or higher.

12. Brazing heat treatment, in which the temperature range is 575 to 630°C and held for more than 0 minutes and 20 minutes or less, and After aging heat treatment, which involves holding the material at a temperature range of 150 to 450°C for 0 to 4 hours, The 0.2% proof stress is 40 MPa or higher. An aluminum alloy brazing sheet according to any one of claims 8 to 11, characterized in that its electrical conductivity is 40% IACS or higher.

13. The chemical composition of the core material is, in mass%, Cu: more than 0.00%, 0.90% or less, Mn: more than 0.00%, less than 0.30%, Cr: more than 0.00%, 0.30% or less, Zn: more than 0.00%, less than 1.00%, Ti: more than 0.00%, less than 0.30%, Ni: more than 0.00%, less than 0.30%, Zr: more than 0.00%, less than 0.30%, V: more than 0.00%, less than 0.30%, and An aluminum alloy brazing sheet according to any one of claims 8 to 11, further characterized by containing one or more Mg in an amount greater than 0.00% and less than or equal to 1.00%.

14. The chemical composition of the core material is, in mass%, Cu: more than 0.00%, 0.90% or less, Mn: more than 0.00%, less than 0.30%, Cr: more than 0.00%, 0.30% or less, Zn: more than 0.00%, less than 1.00%, Ti: more than 0.00%, less than 0.30%, Ni: more than 0.00%, less than 0.30%, Zr: more than 0.00%, less than 0.30%, V: more than 0.00%, less than 0.30%, and The aluminum alloy brazing sheet according to claim 12, further characterized by containing one or more Mg in an amount greater than 0.00% and less than or equal to 1.00%.

15. The chemical composition of the aforementioned brazing material is, in mass%, Contains Si: 3.00-13.00%, Optional, Zn: 0.10–6.00%, and Mg: Contains one or more elements in an amount of 0.10-3.00%, The aluminum alloy brazing sheet according to any one of claims 8 to 11, characterized in that the remainder consists of Al and unavoidable impurities.

16. The chemical composition of the aforementioned brazing material is, in mass%, Contains Si: 3.00-13.00%, Optional, Zn: 0.10–6.00%, and Mg: Contains one or more elements in an amount of 0.10-3.00%, The aluminum alloy brazing sheet according to claim 12, characterized in that the remainder consists of Al and unavoidable impurities.

17. The chemical composition of the aforementioned brazing material is, in mass%, Contains Si: 3.00-13.00%, Optional, Zn: 0.10–6.00%, and Mg: Contains one or more elements in an amount of 0.10-3.00%, The aluminum alloy brazing sheet according to claim 13, characterized in that the remainder consists of Al and unavoidable impurities.

18. The chemical composition of the aforementioned brazing material is, in mass%, Contains Si: 3.00-13.00%, Optional, Zn: 0.10–6.00%, and Mg: Contains one or more elements in an amount of 0.10-3.00%, The aluminum alloy brazing sheet according to claim 14, characterized in that the remainder consists of Al and unavoidable impurities.

Images