JPH07179972A - Al alloy brazing sheet for heat exchanger structural member - Google Patents

Abstract

PURPOSE:To prepare an Al alloy brazing sheet for heat exchanger structural member, capable of holding high strength even after brazing treatment. CONSTITUTION:This Al alloy brazing sheet can be produced by cladding at least one side of a core material of Al alloy, which has a composition consisting of, by weight, 0.7-1.5% Si, 1.5-3% Mn, 0.01-0.25% V, 0.01-O.25% Zr, 0.01-0.25% Cr, and the balance Al with inevitable impurities and further containing, if necessary, one or >=2 kinds among 0.2-1.5% Fe, 0.02-0.25% Ti, 0.05-0.3% Mg, and 0.05-1% Cu, with a brazing filler metal of Al-Si alloy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when used as a structural member for assembling and manufacturing a heat exchanger by brazing, retains high strength even after brazing.
l alloy brazing sheet.

[0002]

2. Description of the Related Art Conventionally, for example, as structural members such as pipes and header plates of heat exchangers such as radiators of automobiles, Japanese Patent Laid-Open No. 57-5840 and Japanese Patent Laid-Open No. 5-58840 have been used.
Many other Al alloy brazing sheets are used, including the Al alloy brazing sheet described in Japanese Patent No. 8082.

[0003]

On the other hand, with the recent miniaturization and weight reduction of heat exchangers, there is a strong demand for thin structural members of the heat exchanger. In all of the Al alloy brazing sheets, the strength after brazing is remarkably reduced, and therefore it is not possible to satisfactorily cope with thinning.

[0004]

Therefore, the present inventors have
From the above viewpoint, focusing on the Al alloy brazing sheet for heat exchanger structural members, which is obtained by clad a brazing material of Al-Si alloy on at least one surface of the core material of Al alloy,
As a result of research to develop an Al alloy brazing sheet that retains high strength even when it is assembled into a heat exchanger by brazing to form a structural member,
In% by weight (hereinafter,% is indicated by% by weight), Si: 0.7 to
1.5%, Mn: 1.5 to 3%, V: 0.01 to
0.25%, Zr: 0.01 to 0.25%, Cr:
If it is composed of an Al alloy containing 0.01 to 0.25% and the balance of Al and unavoidable impurities, the resulting Al alloy brazing sheet will diffuse and penetrate from the brazing material during the brazing process. The solid solution of the Si component to the core material is prevented by the formation of Al-Mn-Si-based compound finely precipitated in the matrix, and as a result, the solidus temperature of the core material is prevented from lowering and local melting is eliminated. , A Si component contained as a solid solution as an alloy component and the Al-Mn
The -Si compound maintains high strength even after brazing, and the co-inclusion of V, Zr, and Cr further suppresses solid solution of the Si component in the core material, and Al-Mn-Si. Since the formation of the system-based compound is promoted, high strength after brazing is secured, and further Fe: 0.2 to 1.5%, Ti:
When 0.02 to 0.25% of either or both of them are contained, the above Al-Mn-Si is contained in these components.
Since it has the effect of refining the system compound, the strength after brazing will be improved, and also in the above core material,
Mg: 0.05-0.3%, Cu: 0.05-1
According to the research result, it is possible to improve the strength after brazing by using either of these components, or both of them.

The present invention was made based on the above research results, and Si: 0.7 to 1.5%,
Mn: 1.5 to 3%, V: 0.01 to 0.25%,
Zr: 0.01-0.25%, Cr: 0.01-0.
25%, and if necessary, Fe: 0.2
~ 1.5%, Ti: 0.02-0.25%, M
g: 0.05 to 0.3%, Cu: 0.05 to 1%,
Brazing, in which a brazing material of an Al-Si alloy is clad on at least one surface of a core material of an Al alloy containing one or more of the above, and the balance consisting of Al and unavoidable impurities. It is characterized by an Al alloy brazing sheet for a heat exchanger structural member having high strength even after the treatment.

Next, in the Al alloy brazing sheet of the present invention, the reason why the component composition of the core material constituting the Al alloy brazing sheet is limited as described above will be explained. (A) Si The Si component is solid-solved in the base material and Al-Mn-S.
Although it has an action of forming an i-type compound to secure the strength after brazing treatment, if the content is less than 0.7%, the desired high strength cannot be secured, while the content is 1. 5
%, The melting point will be sharply lowered, and local melting will occur during the brazing process.
It was set at ~ 1.5%.

(B) Mn The Mn component is Al-Mn- which is dispersed and precipitated in the matrix by combining with the Si component which diffuses and penetrates from the brazing material during the brazing process.
It forms an Si-based compound, thereby suppressing the solid solution of diffused Si into the core material base, and also has the action of ensuring the strength after brazing by the formation of the Al-Mn-Si-based compound, but its content is When the content is less than 1.5%, the desired effect cannot be obtained, while when the content exceeds 3%, the hot workability is deteriorated.
It was set to 5 to 3%, preferably 1.5 to 2.0%.

(C) V, Zr, and Cr In the coexistence of these components, the solid solution of Si in the brazing filler metal during the brazing treatment is suppressed and Al-Mn- It has the effect of promoting the formation of Si-based compounds and thus contributing to the improvement of strength. Therefore, even if the content of any of these components is V: less than 0.01%,
When Zr: less than 0.01% and Cr: less than 0.01%, the desired effect cannot be obtained, while V: 0.25%, Z in any of these components.
If r: 0.25% and Cr: 0.25% are exceeded, the hot workability is deteriorated, so the contents are V: 0.01 to 0.25% and Z, respectively.
r: 0.01 to 0.25%, and Cr: 0.01 to
It was set at 0.25%.

(D) Fe and Ti These components include Al-M which precipitates on the substrate as described above.
The n-Si compound is finely divided and has an action of contributing to the improvement of strength after brazing treatment, so that it is contained as necessary, but the contents thereof are Fe: less than 0.2% and T, respectively.
If i: less than 0.02%, the desired strength-improving effect cannot be obtained, while if the contents exceed Fe: 1.5% and Ti: 0.25%, respectively, the hot workability deteriorates. Therefore, the content of Fe: 0.2 to 1.5
%, Ti: 0.02 to 0.25%.

(E) Mg and Cu These components have the action of forming a solid solution in the base material and also improving the strength after brazing, so they are contained as necessary, but their contents are , Mg: 0.3%, respectively
If less than Cu and less than 0.05% Cu, the desired strength-improving effect cannot be obtained.
If it exceeds 3% and Cu: 1%, the melting point of the core material sharply decreases and local melting occurs during brazing, so the content of Mg: 0.05-0.3% , C
u: It was defined as 0.05 to 1%.

[0011]

EXAMPLES Next, the Al alloy brazing sheet of the present invention will be specifically described by way of examples. Al alloys 1 to 40 for core materials and Al alloys 1 to 4 for brazing materials having the component compositions shown in Tables 1 to 4 were melted and cast into ingots by a usual melting method. Under normal conditions,
After subjected to homogenizing heat treatment, hot-rolled to a hot-rolled sheet with a thickness of 8 mm, and the hot-rolled sheet for brazing material is cold-rolled. .9 mm, in the case of double-sided clad, a cold-rolled sheet with a plate thickness of 1 mm, and the hot-rolled sheet for core material and the cold-rolled sheet for brazing material are superposed according to the combinations shown in Tables 5 and 6, and hot rolled. The aluminum alloy brazing sheet of the present invention (hereinafter referred to as the present invention sheet) 1 to 33 and the comparative Al alloy brazing sheet (hereinafter referred to as the following) were obtained by clad by rolling and subsequently cold rolling to a plate thickness of 0.5 mm. , Comparative sheet) 1 to 7 were manufactured. In each of Comparative Sheets 1 to 7, the content of at least any one of the alloy components constituting the Al alloy of the core material (marked with * in the table) falls outside the range of the present invention. It is a thing. Then, with respect to various sheets obtained as a result, the tensile strength was measured for the purpose of evaluating the strength before the brazing treatment, and further, the brazing treatment conditions, that is, those obtained by clad Al alloys 1 and 2 for brazing filler metal. The atmosphere is a vacuum of 10 ^-4 torr, the others are nitrogen atmospheres, and the temperature is 600 ° C.
After being held at room temperature for 5 minutes, the tensile strength after heat treatment under the condition of air cooling was measured. The measurement results are shown in Tables 5 and 6.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

[0016]

[Table 5]

[0017]

[Table 6]

[0018]

From the results shown in Tables 1 to 6, the sheets of the present invention 1 to 33 retain the high strength before the brazing treatment even after the brazing treatment, while the comparative sheets 1 to 33 retain the high strength before the brazing treatment. As shown in Fig. 7, if any of the constituent components of the Al alloy of the core material deviates to the lower content, the strength after brazing decreases as compared with the strength before brazing. It is clear that it is remarkable. As described above, since the Al alloy brazing sheet of the present invention retains high strength after brazing and before brazing, when applied as a structural member of a heat exchanger in which brazing is essential in the manufacturing process. The thickness of the heat exchanger can be reduced, which greatly contributes to downsizing and weight reduction of the heat exchanger.

Claims (4)

[Claims] 1. An Al alloy core material having Al on at least one surface thereof.
In an Al alloy brazing sheet for a heat exchanger structural member, which is obtained by clad with a brazing material of a Si-based alloy, the core material is, by weight%, Si: 0.7 to 1.5%, Mn: 1.5 to 3%, V: 0.01 to 0.25%, Zr: 0.01 to 0.
25%, Cr: 0.01 to 0.25%, and the balance being composed of an Al alloy having a composition of Al and unavoidable impurities, which maintains high strength even after brazing. Al alloy brazing sheet for heat exchanger structural members. 2. An Al alloy core material having Al on at least one surface thereof.
In an Al alloy brazing sheet for a heat exchanger structural member, which is obtained by clad with a brazing material of a Si-based alloy, the core material is, by weight%, Si: 0.7 to 1.5%, Mn: 1.5 to 3%, V: 0.01 to 0.25%, Zr: 0.01 to 0.
25%, Cr: 0.01 to 0.25%, and further Fe: 0.2 to 1.5%, Ti: 0.02 to 0.
25%, one or two of them, and the rest being composed of an Al alloy having a composition of Al and unavoidable impurities, heat exchange maintaining high strength after brazing Alloy brazing sheet for vessel structural members. 3. An Al alloy core material having Al on at least one surface thereof.
In an Al alloy brazing sheet for a heat exchanger structural member, which is obtained by clad with a brazing material of a Si-based alloy, the core material is, by weight%, Si: 0.7 to 1.5%, Mn: 1.5 to 3%, V: 0.01 to 0.25%, Zr: 0.01 to 0.
25%, Cr: 0.01 to 0.25%, and further Mg: 0.05 to 0.3%, Cu: 0.05 to 1
%, One or two of, and the balance being composed of an Al alloy having a composition of Al and unavoidable impurities, characterized in that it retains high strength even after brazing. Al alloy brazing sheet for structural members. 4. An Al alloy core material having Al on at least one surface thereof.
In an Al alloy brazing sheet for a heat exchanger structural member, which is obtained by clad with a brazing material of a Si-based alloy, the core material is, by weight%, Si: 0.7 to 1.5%, Mn: 1.5 to 3%, V: 0.01 to 0.25%, Zr: 0.01 to 0.
25%, Cr: 0.01 to 0.25%, and further Fe: 0.2 to 1.5%, Ti: 0.02 to 0.
One or two of 25%, Mg: 0.05 to 0.3%, Cu: 0.05 to 1
%, One or two of, and the balance being composed of an Al alloy having a composition of Al and unavoidable impurities, characterized in that it retains high strength even after brazing. Al alloy brazing sheet for structural members.