JP4448758B2 - Aluminum alloy clad material for heat exchangers with excellent brazing, corrosion resistance and hot rolling properties - Google Patents

Description

The present invention relates to an aluminum alloy clad material used in heat exchangers, particularly automobile heat exchangers, in particular evaporators, condensers, radiators, which are joined by brazing in an inert gas atmosphere using a fluoride-based flux or a cesium-based flux. The present invention relates to an aluminum alloy clad material for a heat exchanger excellent in brazing property, corrosion resistance and hot rolling property, which is suitable as a tube material for an aluminum alloy automobile heat exchanger such as a heater, an intercooler, and an oil cooler.

  2. Description of the Related Art An automobile heat exchanger, for example, a radiator, includes a tube and a header that have fins on the outer surface and the inner surface serves as a passage for working fluid (refrigerant). As a tube material for such an automobile radiator or heater, an aluminum alloy having a two-layer structure in which an Al—Mn alloy such as JIS A3003 is used as a core and an Al—Si alloy brazing material is clad on one side of the core. A clad material, a three-layer aluminum alloy clad material in which a brazing material is clad on one surface of the core material and a sacrificial anode material of an Al-Zn alloy or Al-Zn-Mg alloy is clad on the other surface is used. It has been.

  Aluminum alloy heat exchangers are often joined by brazing with an inert gas atmosphere using a fluoride flux or a cesium flux, and the Al-Si brazing filler metal is an aluminum alloy heat exchanger. When the tube is manufactured, it is clad for joining the tube and the fin, joining the tube and the header plate, or brazing when manufacturing the tube from the clad plate. The sacrificial anode material is used, for example, on the inner surface side of the tube, and exerts a sacrificial anode action in contact with the working fluid, thereby preventing pitting corrosion and crevice corrosion of the core material.

  In recent years, with the demand for lighter automobiles, automobile heat exchangers are also required to be made thinner from the viewpoint of energy saving and resource saving, and the tube materials are also becoming thinner. In order to reduce the thickness of the tube material, it is necessary to further increase the strength of the material, and the core material contains a large amount of Mn, Cu, Si, etc., but the inclusion of these elements reduces the corrosion resistance of the core material. Therefore, a material configuration has been proposed in which a large amount of Zn is added to the sacrificial anode material to ensure a potential difference from the core material and to ensure the sacrificial anode effect. In addition, a material structure in which Mg is added to the core material and the sacrificial anode material to further increase the strength has been proposed.

However, when Mg is added to the core material or sacrificial anode material, Mg diffuses to the surface of the brazing material in the brazing process and reacts with the flux to form a compound such as MgF ₂ , which functions as a flux. There is a problem that a sufficient brazing strength cannot be obtained because the brazing defect occurs or Mg in the material is reduced.

  This problem also arises when the aluminum alloy clad material having the three-layer structure is bent and welded to form a flat tube, and a header plate is assembled to this and integrally brazed. However, in recent years, energy saving and work efficiency have been improved. A plate material that is increasing in use from the viewpoint is formed into a tube shape without being welded only by bending, that is, as shown in FIGS. 1 and 2, a brazing material 4 on one side of a core material 3, and another side surface By simply bending the aluminum alloy clad material clad with the sacrificial anode material 5 to the sacrificial anode material 5 at both ends 6 or both ends 6 and both ends 7, the B-type tube is simply bent. This is a particular problem in brazing dies that have the shape 1 or 2 and are manufactured by assembling and integrally brazing the header plate. Conventionally, in order to solve this problem, a method of providing an intermediate material made of an aluminum alloy containing Mn between a core material and a brazing material has been proposed (see Patent Documents 1, 2, and 3).

  Although the diffusion of Mg from the core material and the sacrificial anode material is suppressed by providing the intermediate material of the Al—Mn alloy, for example, the intermediate material of the Al—Mn alloy on one side of the Al—Mn alloy core material. An aluminum alloy clad material is produced in which an Al—Si alloy brazing material is clad through a layer and a sacrificial anode material made of an Al—Zn alloy or an Al—Zn—Mg alloy is clad on the other surface of the core material. In this case, since the intermediate material layer and the sacrificial anode material preferentially extend over the brazing material and the core material during the hot rolling, the clad rate in the rolling direction of the clad material varies, and particularly in the clad material that is thinned, If there is a part where the clad rate is slightly different, the material characteristics such as brazing and corrosion resistance will be greatly different, which makes it difficult to produce a stable clad material. .

In a four-layer clad material in which an intermediate material is clad on one side of an Al-Mn alloy core material and an Al-Si-Mg brazing material is clad on the other surface of the intermediate material and the core material, the deformation resistance of the intermediate material is cored. It has also been proposed to obtain stable clad hot-rollability as 70 to 130% of the deformation resistance of the material (see Patent Document 4), but an Al—Zn alloy instead of a brazing material on the other surface of the core material Alternatively, when a sacrificial anode material made of an Al—Zn—Mg alloy is clad, improvement in clad hot rolling property cannot be obtained, and as described above, the intermediate material layer and the sacrificial anode material are formed during hot rolling. A phenomenon that preferentially extends over brazing material and core material occurs.
JP-A-62-212094 JP-A-4-36432 JP-A-4-36435 Japanese Patent Laid-Open No. 10-53828

  The inventors clad an Al—Si alloy brazing material on one side of an Al—Mn alloy core material through an intermediate layer of Al—Mn alloy, and clad a sacrificial anode material on the other surface of the core material. In order to obtain the aluminum alloy clad that can solve the above-mentioned problems in the tube material of the heat exchanger and can achieve corrosion resistance, high strength for thinning and proper hot rolling properties, The combination of brazing material, brazing material and sacrificial anode material was studied.

  In order to achieve sufficient strength and corrosion resistance for the thinned clad material, and to obtain appropriate hot rollability in its production, a low-strength Al-Zn alloy such as the conventional A7072 alloy is applied as a sacrificial anode material In such a case, as will be described below, the strength decrease is large, and the increase in strength cannot be achieved. When Mg is added to the sacrificial anode material, a sufficient strength can be obtained, but as described above, there are problems in brazability and hot rolling property.

  That is, when the thickness of the clad material is relatively large as in the conventional case, such as 0.3 mm, the thickness of the sacrificial anode material layer is required to be about 0.030 mm in order to maintain the corrosion resistance of the inner surface. Since the ratio to the total plate thickness is 10%, even if a low-strength alloy such as an A7072 alloy is used as the sacrificial anode material, the strength decrease as a tube material is slight, but the thickness of the clad material is 0 Even when the thickness is reduced to 15 mm, the thickness of the sacrificial anode material layer is also required to be about 0.030 mm in order to maintain the corrosion resistance of the inner surface, and the proportion of the total plate thickness is 20%. When a low-strength alloy such as an A7072 alloy is used as the sacrificial anode material, the strength is greatly reduced.

  As a result of repeated tests and studies, by adding Zn and Mn to the sacrificial anode material, the strength of the sacrificial anode material is improved and the corrosion resistance is maintained, and sufficient strength and corrosion resistance are achieved in the thinned cladding material. The hot-rollability can also be combined with an Al—Si alloy brazing material, an Al—Mn alloy intermediate material, an Al—Mn alloy core material, and a sacrificial anode material containing Zn and Mn. It has been found that good hot clad rollability can be obtained when hot rolling.

  The present invention has been made as a result of further investigation based on the above knowledge, and its purpose is to suppress the diffusion of Mg from the core material to the brazing material surface in the brazing process and to react with the flux. It does not impair brazeability, has good hot clad rollability in the manufacturing process, does not cause variations in the clad rate, and can achieve high strength and excellent corrosion resistance. Aluminum alloy clad materials used in exchangers, especially automotive heat exchangers, especially evaporators, condensers, radiators, heaters, intercoolers, joined by brazing in an inert gas atmosphere using fluoride or cesium fluxes, Aluminum for heat exchangers suitable as a tube material for aluminum alloy automotive heat exchangers such as oil coolers It is to provide an alloy cladding material.

In order to achieve the above object, an aluminum alloy clad material for a heat exchanger according to claim 1 is formed by clad a sacrificial anode material on one surface of a core material and clad a brazing material on the other surface with an intermediate material. A four-layer clad material of an alloy, the core material comprising Mn: 0.8 to 1.8%, Mg: 0.1 to 1.0%, and composed of an aluminum alloy composed of the balance Al and impurities. The intermediate material is an aluminum alloy containing Mn: 0.8 to 1.8%, Cu: 0.4 to 0.8% , Si: 0.7 to 1.1% , and the balance Al and impurities. The sacrificial anode material is composed of an aluminum alloy containing Mn: 0.8 to 1.8%, Zn: 0.5 to 10%, the balance Al and impurities, and the brazing material is Si: 6 Aluminum containing about 13%, balance Al and impurities It is characterized by being comprised with a hum alloy.

The aluminum alloy clad material for a heat exchanger according to claim 2 is the aluminum alloy clad material for heat exchanger according to claim 1, wherein the core material contains Mn: 0.8 to 1.8%, Mg: 0.1 to 1.0%, Si: 0.7-1.1%, Fe: 0.5-1.0%, Cu: 0.8% or less, Ni: 0.1-1.0%, Cr: 0.02-0.3 %, Zr: 0.02 to 0.3%, Ti: 0.05 to 0.35%, or one or more of them, and the balance being composed of an aluminum alloy composed of Al and impurities. Features.

An aluminum alloy clad material for a heat exchanger according to claim 3 is the aluminum alloy clad material according to claim 1 or 2, wherein the intermediate material is further Fe : 0.5-1.0%, Ni: 0.1-1.0%, Cr : 0.02-0.3%, Zr: 0.02-0.3%, Ti: 0.05-0.35% of 1 type or 2 types or more are contained.

The aluminum alloy clad material for a heat exchanger according to claim 4 is the aluminum alloy clad material according to any one of claims 1 to 3 , wherein the sacrificial anode material is further Si: 0.7 to 1.1%, Fe: 0.5 to 1. 1% of 0%, Ni: 0.1-1.0%, Cr: 0.02-0.3%, Zr: 0.02-0.3%, Ti: 0.05-0.35% It contains a seed or two or more kinds.

The aluminum alloy clad material for a heat exchanger according to claim 5 is any one of claims 1 to 4 , wherein the brazing material is further Fe: 0.8 to 2.0%, Zn: 0.5 to 5.0. %, Cu: 0.5~5.0%, Sr : characterized in that it contains one or more of 0.005% to 0.1%.

Aluminum alloy clad sheet according to claim 6, in any one of claims 1 to 5, wherein the core material further, V: 0.01~0.3%, B: 0.01~0.3 % Of 1% or 2%.

Aluminum alloy clad sheet according to claim 7, in any one of claims 1 to 6, wherein the intermediate member further, V: 0.01~0.3%, B: 0.01~0.3 % Of 1% or 2%.

Aluminum alloy clad sheet according to claim 8, in any one of claims 1 to 7, wherein the sacrificial anode material further, V: 0.01~0.3%, B: 0.01~0. It is characterized by containing one or two of 3%.

The aluminum alloy clad material for a heat exchanger according to claim 9 is the aluminum alloy clad material for heat exchanger according to any one of claims 1 to 8 , wherein the brazing material further includes one or two of In: 0.05% or less and Sn: 0.05% or less. It contains seeds.

According to the present invention, Mg diffusion from the core material to the brazing material surface is suppressed in the brazing process, and it does not adversely affect the brazing property by reacting with the flux. It is possible to achieve high strength and excellent corrosion resistance without any variation in cladding ratio, and aluminum alloy cladding material used in heat exchangers, especially automotive heat exchangers, especially fluoride-based. Aluminum for heat exchangers suitable as a tube material for aluminum alloy automotive heat exchangers such as evaporators, condensers, radiators, heaters, intercoolers, and oil coolers that are joined by brazing in an inert gas atmosphere using flux or cesium flux An alloy cladding material is provided .

Hereinafter, the components of the core material, the intermediate material, the sacrificial anode material and the brazing material in the aluminum alloy clad material of the present invention and the reasons for the limitation will be described.
(Core material)
Mn: 0.8 to 1.8%
Mn functions to improve the corrosion resistance by improving the strength of the core material and making the potential of the core material noble and increasing the potential difference from the sacrificial anode material. The preferable content of Mn is in the range of 0.8 to 1.8%. If the content is less than 0.8%, the effect is small. If the content exceeds 1.8%, a coarse compound is produced during casting, and the rolling processability is low. It decreases and it becomes difficult to obtain a healthy plate (core material). A more preferable content range of Mn is 1.0 to 1.3%.

Mg: 0.1 to 1.0%
Mg improves the strength of the core material. The preferable content of Mg is in the range of 0.1 to 1.0%. If the content is less than 0.1%, the effect is small. If the content exceeds 1.0%, an inert gas is used using a fluoride-based flux. When heat brazing is performed in an atmosphere, even if an intermediate material is disposed, Mg diffuses to the brazing material surface during brazing and reacts with the fluoride-based flux, brazing properties are easily hindered, such as MgF ₂ A compound is formed and a brazing defect is likely to occur. A more preferable content range of Mg is 0.1 to 0.6%.

Si: 0.7 to 1.1%
Si has the effect of improving the strength of the core material. The preferable content of Si is in the range of 0.7 to 1.1%. If the content is less than 0.7%, the effect is small. If the content exceeds 1.1%, the corrosion resistance of the core material decreases, and The melting point is lowered, and local melting tends to occur during brazing with heating. The more preferable content range of Si is 0.8 to 1.0%.

Fe: 0.5 to 1.0%
Fe has the effect of improving the strength of the core material. The preferable content of Fe is in the range of 0.5 to 1.0%. If the content is less than 0.5%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the core material increases. The more preferable content range of Fe is 0.5 to 0.8%.

Cu: 0.8% or less Cu functions to improve the corrosion resistance by improving the strength of the core material, making the potential of the core material noble, and increasing the potential difference from the sacrificial anode material. Further, Cu in the core material diffuses into the sacrificial anode material and the intermediate material at the time of heat brazing, and forms a gentle Cu concentration gradient in the thickness direction of the sacrificial anode material and the intermediate material. The potential on the side becomes noble, the potential on the surface side of the sacrificial anode material and the surface side of the intermediate material becomes base, and a gentle potential gradient is formed in the thickness direction of the sacrificial anode material and intermediate material. Becomes a full corrosive type. The preferable content of Cu is in the range of 0.8% or less. If it exceeds 0.8%, the corrosion resistance of the core material is lowered, and the melting point is lowered, so that local melting is likely to occur during heat brazing. The more preferable content range of Cu is 0.4 to 0.6%.

Ni: 0.1 to 1.0%
Ni functions to improve the strength of the core material. The preferable content of Ni is in the range of 0.1 to 1.0%. If the content is less than 0.1%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the core material increases. A more preferable content range of Ni is 0.5 to 0.8%.

Cr: 0.02-0.3%, Zr: 0.02-0.3%
When Cr and Zr are contained within the above range, the crystal grain size of the core material is coarsened, and Mg grain boundary diffusion during brazing heating is suppressed. If the content is less than 0.02%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected. The more preferable content ranges of Cr and Zr are each 0.05 to 0.2%.

Ti: 0.05 to 0.35%
Ti is divided into a high concentration region and a low region in the thickness direction of the core material, and these regions are alternately distributed in a layered manner, and the low Ti concentration region corrodes preferentially compared to the high region. It has the effect of layering the corrosion form, and this effect prevents the progress of intergranular corrosion in the plate thickness direction and improves the pitting corrosion resistance of the material. The preferable content of Ti is in the range of 0.05 to 0.35%. If it is less than 0.05%, the effect is small, and if it exceeds 0.35%, casting becomes difficult and workability is reduced. It becomes difficult to produce sound materials. A more preferable content range of Ti is 0.1 to 0.2%.

V: 0.01 to 0.3%, B: 0.01 to 0.3%
When V and B are contained within the above range, the crystal grain size of the core material is coarsened, and Mg grain boundary diffusion during brazing heating is suppressed. If the content is less than 0.01%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected.

(Intermediate material)
Mn: 0.8 to 1.8%
Mn improves the strength of the intermediate material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the sacrificial anode material and the brazing material. The preferable content of Mn is in the range of 0.8 to 1.8%. If the content is less than 0.8%, the effect is small. If the content exceeds 1.8%, a coarse compound is produced during casting, and the rolling processability is low. It becomes difficult to obtain a healthy plate material. A more preferable content range of Mn is 1.0 to 1.3%.

Si: 0.7 to 1.1%
Si improves the strength of the intermediate material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the sacrificial anode material and the brazing material. The preferable content of Si is in the range of 0.7 to 1.1%. If the content is less than 0.7%, the effect is small. If the content exceeds 1.1%, the corrosion resistance of the intermediate material decreases, and The melting point is lowered, and local melting tends to occur during brazing with heating. The more preferable content range of Si is 0.8 to 1.0%.

Fe: 0.5 to 1.0%
Fe improves the strength of the intermediate material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the sacrificial anode material and the brazing material. The preferable content of Fe is in the range of 0.5 to 1.0%. If the content is less than 0.5%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the intermediate material increases. The more preferable content range of Fe is 0.5 to 0.8%.

Cu: 0.8% or less Cu improves the strength of the intermediate material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the sacrificial anode material, and the brazing material. Further, it functions to make the potential of the intermediate material noble and increase the potential difference from the brazing material to improve the anticorrosion effect. Furthermore, Cu in the intermediate material diffuses into the core material and the brazing material during the heat brazing to form a gentle Cu concentration gradient in the thickness direction of the core material and the brazing material. As a result, the intermediate material and the core material Since the potential on the surface side of the brazing material becomes base and a gentle potential gradient is formed in the thickness direction of the brazing material, the corrosion form becomes a full corrosion type. The preferable content of Cu is in the range of 0.8% or less. If it exceeds 0.8%, the corrosion resistance of the intermediate material is lowered, and the melting point is lowered, so that local melting is likely to occur during heat brazing. The more preferable content range of Cu is 0.4 to 0.6%. In addition, when making Cu contain in an intermediate material, it is desirable not to add Zn.

Ni: 0.1 to 1.0%
Ni functions to improve the strength of the intermediate material, increase the deformation resistance during hot rolling, and reduce the difference in deformation resistance between the core material, the sacrificial anode material and the brazing material. The preferable content of Ni is in the range of 0.1 to 1.0%. If the content is less than 0.1%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the intermediate material increases. A more preferable content range of Ni is 0.5 to 0.8%.

Cr: 0.02-0.3%, Zr: 0.02-0.3%
When Cr and Zr are contained within the above range, the grain size of the intermediate material is coarsened and Mg grain boundary diffusion during brazing heating is suppressed. If the content is less than 0.02%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected. The more preferable content ranges of Cr and Zr are each 0.05 to 0.2%.

Ti: 0.05 to 0.35%
Ti is divided into a high concentration region and a low region in the thickness direction of the intermediate material, and these regions are alternately distributed in layers, and the low Ti concentration region corrodes preferentially compared to the high region. It has the effect of layering the corrosion form, and this effect prevents the progress of intergranular corrosion in the plate thickness direction and improves the pitting corrosion resistance of the material. The preferable content of Ti is in the range of 0.05 to 0.35%. If it is less than 0.05%, the effect is small, and if it exceeds 0.35%, casting becomes difficult and workability is reduced. It becomes difficult to produce sound materials. A more preferable content range of Ti is 0.1 to 0.2%.

V: 0.01 to 0.3%, B: 0.01 to 0.3%
When V and B are contained within the above range, the grain size of the intermediate material is coarsened, and Mg grain boundary diffusion during brazing heating is suppressed. If the content is less than 0.01%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected.

In: 0.05% or less, Sn: 0.05% or less In the case where Cu is not contained in the intermediate material, the addition of In and Sn makes the potential of the intermediate material low, and ensures the sacrificial anode effect on the core material. It functions to prevent pitting and crevice corrosion of the material. The preferred content is in the range of 0.05% or less, and if it exceeds 0.05%, the self-corrosion property of the intermediate material increases. More preferable content ranges of In and Sn are 0.01 to 0.03%, respectively.

(Sacrificial anode material)
Mn: 0.8 to 1.8%
Mn improves the strength of the sacrificial anode material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the intermediate material and the brazing material. Further, as a result of the pitting corrosion being dispersed by the Al—Mn compound as a starting point of corrosion, the corrosion resistance is improved. The preferable content of Mn is in the range of 0.8 to 1.8%. If the content is less than 0.8%, the effect is small. If the content exceeds 1.8%, a coarse compound is produced during casting, and the rolling processability is low. It becomes difficult to obtain a healthy plate material. A more preferable content range of Mn is 1.0 to 1.3%.

Zn: 0.5 to 10.0%
Zn lowers the potential of the sacrificial anode material, maintains the sacrificial anode effect on the core material, and prevents pitting corrosion and crevice corrosion of the core material. The preferable content of Zn is in the range of 0.5 to 10.0%. If the content is less than 0.5%, the effect is small, and if it exceeds 10.0%, the self-corrosion property of the sacrificial anode material increases. A more preferable content range of Zn is 2.0 to 5.0%.

Si: 0.7 to 1.1%
Si improves the strength of the sacrificial anode material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the intermediate material and the brazing material. In addition, as a result of the Al—Mn—Fe—Si based compound becoming a starting point of corrosion and the corrosion being dispersed, the corrosion resistance is improved. The preferable content of Si is in the range of 0.7 to 1.1%. If the content is less than 0.7%, the effect is small. If the content exceeds 1.1%, the corrosion resistance of the sacrificial anode material is lowered. The more preferable content range of Si is 0.8 to 1.0%.

Fe: 0.5 to 1.0%
Fe improves the strength of the sacrificial anode material, increases the deformation resistance during hot rolling, and reduces the difference in deformation resistance between the core material, the intermediate material and the brazing material. In addition, as a result of the Al—Mn—Fe—Si based compound becoming a starting point of corrosion and the corrosion being dispersed, the corrosion resistance is improved. The preferable content of Fe is in the range of 0.5 to 1.0%. If the content is less than 0.5%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the sacrificial anode material increases. The more preferable content range of Fe is 0.5 to 0.8%.

Ni: 0.1 to 1.0%
Ni functions to improve the strength of the sacrificial anode material, increase the deformation resistance during hot rolling, and reduce the difference in deformation resistance from the core material, intermediate material and brazing material. The preferable content of Ni is in the range of 0.1 to 1.0%. If the content is less than 0.1%, the effect is small, and if it exceeds 1.0%, the self-corrosion property of the sacrificial anode material increases. A more preferable content range of Ni is 0.5 to 0.8%.

Ti: 0.05 to 0.35%
Ti is divided into high-concentration regions and low-concentration regions in the thickness direction of the sacrificial anode material, and these regions are alternately distributed in layers, and the low-Ti concentration regions corrode preferentially over the high regions. This has the effect of making the corrosion form into a layer, and this effect prevents the progress of intergranular corrosion in the plate thickness direction and improves the pitting corrosion resistance of the material. The preferable content of Ti is in the range of 0.05 to 0.35%. If it is less than 0.05%, the effect is small, and if it exceeds 0.35%, casting becomes difficult and workability is reduced. It becomes difficult to produce sound materials. A more preferable content range of Ti is 0.1 to 0.2%.

Cr: 0.02-0.3%, Zr: 0.02-0.3%
When Cr and Zr are contained within the above range, the grain size of the sacrificial anode material is coarsened, and Mg grain boundary diffusion during brazing heating is suppressed. If the content is less than 0.02%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected. The more preferable content ranges of Cr and Zr are each 0.05 to 0.2%.

V: 0.01 to 0.3%, B: 0.01 to 0.3%
V and B, when contained within the above range, make the grain size of the sacrificial anode material coarse and suppress Mg grain boundary diffusion during brazing heating. If the content is less than 0.01%, the effect is small. If the content exceeds 0.3%, the effect is saturated, and no further effect can be expected.

In: 0.05% or less, Sn: 0.05% or less In and Sn lower the potential of the sacrificial anode material, ensure the sacrificial anode effect on the core material, and prevent pitting corrosion and crevice corrosion of the core material. It works as follows. The preferred content is in the range of 0.05% or less, and if it exceeds 0.05%, the self-corrosion property of the sacrificial anode material increases. More preferable content ranges of In and Sn are 0.01 to 0.03%, respectively.

(Brazing material)
Si: 6-13%
As the brazing material, a commonly used Al—Si alloy containing 6 to 13% of Si is applied. If Si is less than 6%, the fluidity is lowered and does not act effectively as a wax. If Si exceeds 13%, it is difficult to produce a sound material.

Fe: 0.8 to 2.0%
Fe forms an Al-Fe-based or Al-Fe-Si-based compound, and these compounds serve as a starting point for corrosion to disperse the corrosion. As a result, the corrosion resistance of the outer surface (the brazing filler metal side) is improved. The preferable content of Fe is in the range of 0.8 to 2.0%. If the content is less than 0.8%, the effect is small, and if it exceeds 2.0%, the corrosion resistance of the outer surface is lowered. A more preferable content range of Fe is 0.8 to 1.0%.

Zn: 0.5 to 5.0%
Zn lowers the potential of the brazing material, maintains the sacrificial anode effect on the intermediate material and the core material, and prevents pitting corrosion and crevice corrosion of the core material from the outer surface. Further, the coexistence with Cu lowers the melting point of the brazing material. The preferable content of Zn is in the range of 0.5 to 5.0%. If the content is less than 0.5%, the effect is small, and if it exceeds 5.0%, the self-corrosion of the brazing material increases. The more preferable content range of Zn is 0.9 to 1.5%.

Cu: 0.5 to 5.0%
Cu coexists with Zn to lower the melting point of the brazing material. The preferable content of Cu is in the range of 0.5 to 5.0%. If the content is less than 0.5%, the effect is small. If the content exceeds 5.0%, the self-corrosion resistance of the brazing material increases. A more preferable content range of Cu is 1 to 3%.

Sr: 0.005 to 0.1%
Sr has the effect of making the presence form of Si particles finer and uniform, and as a result, the melting of the brazing becomes uniform and the brazing property is improved. Moreover, since the presence form of the Si particles after brazing becomes uniform, the corrosion resistance of the outer surface is improved. The preferable content of Sr is in the range of 0.005 to 0.1%. If the content is less than 0.005%, the effect is small, and even if the content exceeds 0.1%, the effect is saturated. The effect cannot be expected. In addition, an equivalent effect is acquired also by containing Na: 1-100 ppm and Sb: 0.001-0.5%.

In: 0.05% or less, Sn: 0.05% or less In and Sn make the sacrificial anode effect on the intermediate material and the core material reliable by lowering the potential of the brazing material, and pitting corrosion and gaps in the core material. Functions to prevent corrosion. The preferable content is in the range of 0.05% or less, and when it exceeds 0.05%, the self-corrosion property of the brazing material increases. More preferable content ranges of In and Sn are 0.01 to 0.03%, respectively.

  The aluminum alloy clad material of the present invention is formed by, for example, ingot-making an aluminum material constituting a core material, an intermediate material, a sacrificial anode material and a brazing material by, for example, continuous casting, and after homogenizing treatment as necessary, for example, an intermediate material The ingots of the sacrificial anode material and the brazing material are each hot-rolled to a predetermined thickness and then combined with the core material ingot to form a clad material by hot rolling according to a conventional method, and then cold-rolled, intermediate It is manufactured by setting it to a predetermined thickness by annealing and cold rolling. The ingot of the core material is also hot-rolled to a predetermined thickness, several hot-rolled core materials are stacked, and hot-clad rolling is combined with the intermediate material, sacrificial anode material and brazing material hot-rolled material You can also

  In this case, the core material, intermediate material, sacrificial anode material and brazing material are deformed during hot rolling after combination (hot rolling temperature: 400 to 500 ° C.) by adjusting the components of each constituent material of the aluminum alloy clad material, for example. Resistance ratio, (deformation resistance of brazing material / deformation resistance of intermediate material), (deformation resistance of brazing material / deformation resistance of core material), (deformation resistance of brazing material / deformation resistance of sacrificial anode material), (intermediate material) (Deformation resistance of core material / deformation resistance of core material), (deformation resistance of intermediate material / deformation resistance of sacrificial anode material), and (deformation resistance of core material / deformation resistance of sacrificial anode material) in the range of 0.7 to 1.4 As a result, it is possible to reduce the preferential extension of the intermediate material and the sacrificial anode material, and to achieve good hot clad rollability without causing variations in the clad rate.

  Examples of the present invention will be described below in comparison with comparative examples. These examples show one embodiment of the present invention, and the present invention is not limited to these examples.

Example 1
Alloys for core materials having compositions shown in Tables 1-2 by continuous casting, alloys for intermediate materials having compositions shown in Tables 3-4, alloys for sacrificial anode materials having compositions shown in Tables 5-6, and Tables 7-7 The alloy for brazing filler metal having the composition shown in FIG. 8 was ingot, and among the obtained ingots, the ingots for the core alloy, the intermediate alloy, and the sacrificial anode alloy were homogenized.

  Next, the ingot of the alloy for intermediate material, the alloy for sacrificial anode material, and the alloy for brazing material is hot-rolled to a predetermined thickness, and the hot-rolled sheet and the ingot of the core material alloy are heated as a combined material. Cold rolling was performed to obtain a clad material. Thereafter, a plate material (cladding material, tempered H14) having a thickness of 0.15 mm was obtained by cold rolling, intermediate annealing, and cold rolling. The composition of the clad material was 0.02 to 0.03 mm for the intermediate material, 0.02 to 0.03 mm for the sacrificial anode material, 0.02 to 0.03 mm for the brazing material, and the rest as the core material.

  Using the obtained aluminum alloy clad material as a test material, (1) Tensile strength, (2) Brazing property, (3) Corrosion resistance of the inner surface (sacrificial anode material side), (3) Between each constituent material The deformation resistance ratio was evaluated. The results are shown in Tables 9-15.

  Tensile strength: The obtained clad material (test material) is applied as a single plate with fluoride-based flux and heated to a brazing temperature of 600 ° C. (material temperature) in a nitrogen gas atmosphere. Go and measure the tensile strength.

  Brazing property: As shown in FIG. 3, a gap is formed between the obtained clad material (test material) and the 3003 alloy plate (thickness: 1.0 mm) via the spacer rod. Combined with each other, fixed with a thin wire of SUS304 to produce an inverted T-shaped gap filling test piece (dimension unit: mm), applied with a fluoride-based flux, and 600 ° C. (material temperature) in a nitrogen gas atmosphere The brazing temperature was evaluated by measuring the filling length of the brazing material.

Corrosion resistance of the inner surface (sacrificial anode material side): The obtained clad material (test material) is heated to a brazing temperature of 600 ° C. (material temperature) in a nitrogen gas atmosphere by applying a fluoride flux as a single plate. After that, the inner surface was subjected to a corrosion test under the following conditions.
Corrosion solution: Cl ⁻ : 300 ppm, SO ₄ ²⁻ : 100 ppm, Cu ²⁺ : 10 pm
Specific liquid volume: 5 mL / cm ²
Seal: The brazing filler metal surface and the end surface were sealed with silicon resin.
Test method: After immersing in a corrosive liquid heated to 88 ° C. for 8 hours, a cycle of cooling and holding at 25 ° C. for 16 hours was repeated for 4 months, and the maximum corrosion depth was measured.

Deformation resistance ratio between each component: For the core material, the ingot is homogenized, and for the intermediate material, sacrificial anode material and brazing material, the ingot is hot-rolled into a hot-rolled material. A cylindrical test piece having a diameter of 8 mm and a height of 16 mm is cut out and subjected to an upsetting test at 400 to 500 ° C., which is the same as the hot clad rolling temperature, and the deformation resistance is measured. Deformation resistance of brazing material / deformation resistance of intermediate material), (deformation resistance of brazing material / deformation resistance of core material), (deformation resistance of brazing material / deformation resistance of sacrificial anode material), (deformation resistance of intermediate material / core material) Deformation resistance), (deformation resistance of intermediate material / deformation resistance of sacrificial anode material), and (deformation resistance of core material / deformation resistance of sacrificial anode material). The upsetting test conditions were that the stroke speed was 10 mm / min, the upsetting rate was changed from 20% to 80%, the deformation resistance was measured, and the average value was obtained. Regarding the measurement of deformation resistance, a load-displacement diagram and a stress-strain diagram are obtained by upsetting tests, and the correction coefficient f obtained from the maximum load P, initial cross-sectional area A ₀ , and upsetting rate of each test. Thus, the deformation resistance at each upsetting rate is calculated from the equation of deformation resistance = P / (A ₀ × f) to obtain an average value (Kosakada, Kawasaki, Mori: Annals of the CIRP, Vol. 30, No.1, see 1981).

As can be seen in Tables 9-15, the test materials No. 1-133 (No. 2, 4, 36, 38, 70, 72, 75, 77, 80, 82, 85, 87, 90, 92, 95, 97, 100, 103, 105, 108, 110, 113, 115, 118, 120, 123, 125, 128, 130, and 133) all have a tensile strength exceeding 190 MPa, and have excellent brazing properties with a filling length exceeding 10 mm in the gap filling test. The maximum corrosion depth in the internal corrosion test was less than 0.1 mm, and it had good corrosion resistance. The deformation resistance ratio between the components was also in the range of 0.7 to 1.4. The test material No. 2, 4, 36, 38, 70, 72, 75, 77, 80, 82, 85, 87, 90, 92, 95, 97, 100, 103, 105, 108, 110, 113, 115, 118, 120, Reference numerals 123, 125, 128, 130, and 133 are shown as reference examples.

In addition, as a method for improving the brazing property, in order to control the amount of Mg in the core material that diffuses through the intermediate material to the brazing material side, the heat pattern during brazing is calculated by integrating the diffusion coefficient of Mg over time, _{D (t) dt = D 0} exp {-Q / RT (t)} ( where, D _0: number term vibration ^{(1.24 × 10 -4 m 2 /} s), Q: activation energy (131000J / mol ), R: gas constant (8.3145 J / mol · K), T: temperature (K), t: time (s)) are controlled to be 3 × 10 ⁻¹⁰ (m ² ) or less, intermediate material It is effective to set the Mg concentration at the interface with the brazing material to 0.1% or less. As a result of obtaining the time integral of the diffusion coefficient at the time of brazing, it was 2 × 10 ⁻¹⁰ for all the test materials. It was.

Comparative Example 1
The core material alloy having the composition shown in Table 16 and the sacrificial anode material alloy having the composition shown in Table 17 were ingot by continuous casting and treated in the same manner as in Example 1. The material, the sacrificial anode material, and the brazing material are combined and hot-rolled to obtain a clad material, and then a plate material (clad material, tempered H14) having a thickness of 0.15 mm is obtained by cold rolling, intermediate annealing, and cold rolling. It was. The configuration of the clad material is the same as in Example 1, the intermediate material is 0.020 to 0.030 mm, the sacrificial anode material is 0.020 to 0.030 mm, the brazing material is 0.020 to 0.030 mm, and the rest is the core. A material was used.

  Using the obtained clad material as a test material, (1) Tensile strength, (2) Brazing property, (3) Corrosion resistance of the inner surface (sacrificial anode material side), (3) Each component The deformation resistance ratio between them was evaluated. The results are shown in Table 18.

  As shown in Table 18, the test material No. No. 134 is inferior in tensile strength because the core material does not contain Mg. Test material No. No. 135 is inferior in tensile strength because the sacrificial anode material does not contain Mn. In addition, since the deformation resistance ratio between each component is as large as 1.5, the variation in the clad rate is large, and it is outside the range of the clad rate tolerance (median ± median × 0.2) defined by JIS. .

It is sectional drawing which shows the Example of the tube material (B type tube shape) manufactured from the aluminum alloy clad material by this invention. It is sectional drawing which shows the other Example of the tube material (B type tube shape) manufactured from the aluminum alloy clad material by this invention. FIG. 3 is a diagram showing an inverted T-shaped gap filling test piece manufactured in Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 B type tube shape 2 B type tube shape 3 Core material 4 Brazing material 5 Sacrificial anode material 6 Both end surfaces 7 Both end portions

Claims (9)

A four-layer clad material of aluminum alloy in which a sacrificial anode material is clad on one surface of a core material and a brazing material is clad on the other surface with an intermediate material, and the core material has a Mn: 0.8 to 1 0.8% (mass%, the same shall apply hereinafter), Mg: 0.1 to 1.0%, the balance being composed of an aluminum alloy composed of Al and impurities, the intermediate material is Mn: 0.8 to 1.8 %, Cu: 0.4 to 0.8% , Si: 0.7 to 1.1% , the balance being made of an aluminum alloy composed of Al and impurities, the sacrificial anode material is Mn: 0.8 to 1.8%, Zn: 0.5 to 10%, and composed of an aluminum alloy composed of the balance Al and impurities, and the brazing material contains Si: 6 to 13%, and the balance Al and impurities Brazeability, corrosion resistance and Aluminum alloy clad material for heat exchangers with excellent hot rollability. The core material contains Mn: 0.8 to 1.8%, Mg: 0.1 to 1.0%, Si: 0.7 to 1.1%, Fe: 0.5 to 1 0.0%, Cu: 0.8% or less, Ni: 0.1-1.0%, Cr: 0.02-0.3%, Zr: 0.02-0.3%, Ti: 0.05 The brazing property, corrosion resistance, and hot rolling property according to claim 1, characterized in that it comprises one or more of ~ 0.35% and is composed of an aluminum alloy consisting of the balance Al and impurities. Excellent aluminum alloy clad material for heat exchangers. The intermediate material is further Fe : 0.5-1.0%, Ni: 0.1-1.0%, Cr: 0.02-0.3%, Zr: 0.02-0.3% Ti: 0.05-0.35% of 1 type or 2 types or more are contained, The heat exchange excellent in brazing property, corrosion resistance, and hot rolling property of Claim 1 or 2 characterized by the above-mentioned Aluminum alloy clad material for equipment. The sacrificial anode material is further Si: 0.7-1.1%, Fe: 0.5-1.0%, Ni: 0.1-1.0%, Cr: 0.02-0.3 %, Zr: 0.02-0.3%, Ti: 0.05-0.35% of 1 type or 2 types or more are contained, The any one of Claims 1-3 characterized by the above-mentioned. Aluminum alloy clad material for heat exchangers with excellent brazing, corrosion resistance and hot rolling properties. The brazing material is further Fe: 0.8-2.0%, Zn: 0.5-5.0%, Cu: 0.5-5.0%, Sr: 0.005-0.1% The aluminum alloy clad material for a heat exchanger excellent in brazing property, corrosion resistance, and hot rolling property according to any one of claims 1 to 4, characterized by containing one or more of them. The core material further contains one or two of V: 0.01 to 0.3% and B: 0.01 to 0.3%. The aluminum alloy clad material for heat exchangers excellent in brazing property, corrosion resistance and hot rollability according to any one of the above. The intermediate material further contains one or two of V: 0.01 to 0.3% and B: 0.01 to 0.3%. The aluminum alloy clad material for heat exchangers excellent in brazing property, corrosion resistance and hot rollability according to any one of the above. The sacrificial anode material further contains one or two of V: 0.01 to 0.3% and B: 0.01 to 0.3%. The aluminum alloy clad material for heat exchangers having excellent brazeability, corrosion resistance, and hot rolling properties. The brazing material according to any one of claims 1 to 8 , wherein the brazing material further contains one or two of In: 0.05% or less and Sn: 0.05% or less. Aluminum clad material for heat exchangers with excellent corrosion resistance and hot rollability.

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