JP2007131872A - Aluminum alloy clad material for heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy clad material by which manufacturing can be simplified and also manufacturing costs can be reduced and which has excellent strength and brazability and can be suitably used for a reinforcing material etc. for heat exchangers. <P>SOLUTION: The clad material is composed of two layers constituted in such a way that one side of a core material having a composition consisting of >1.2 to 1.8% Mn, >0.8 to 1.4% Si, 0.4 to 1.0% Cu, 0.05 to <0.2% Mg and the balance Al with inevitable impurities is clad with a brazing filler metal having a composition consisting of 6 to 12% Si and the balance Al with inevitable impurities or a brazing filler metal having a composition consisting of 6 to 12% Si, 0.2 to 5.0% Zn and the balance Al with inevitable impurities. Moreover, overall sheet thickness is 1.0 to 3.5 mm, and the cladding ratio of the brazing filler metal is 5 to 15%. By this method, high strength can be obtained without deteriorating brazability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-strength aluminum alloy clad material excellent in brazing property, which is used in a heat exchanger such as an automobile radiator or a heater core, and is particularly suitable as a reinforcing material.

The reinforcing material used in the heat exchanger for automobiles is a two-layer structure in which an Al-Mn alloy such as JIS3003 alloy is used as a core material and a brazing material made of an Al-Si alloy such as JIS4343 is clad on one side. The material is used. Also, an Al—Mn alloy such as JIS3003 alloy is used for the core material, an Al—Zn alloy such as JIS7072 alloy is clad on one side of the core material, and an Al—Si alloy such as JIS4343 or JIS4045 alloy is used on the other side. A three-layer material clad with an alloy skin material is also used.
Reinforcing materials improve the structural strength of heat exchangers in response to the recent demands for reduction in size and thickness in heat exchangers such as radiators and heater cores.

As materials for high strength, clad materials are proposed in Patent Documents 1 and 2. All of these materials contain Mg in the core material, and those proposed in Patent Document 1 have been proposed in Patent Document 2 in which the strength is improved by the Al—Mg—Zn-based alloy of the core material. The strength is improved in the same way by adding 0.4% or more of Mg to the core material.
Japanese Patent Laid-Open No. 55-161044 JP 2002-273597 A

  However, in the material for high strength described above, Mg contained in the core material has a great influence on the brazing property. Therefore, it is possible to prevent Mg from diffusing and be able to achieve good brazing. In addition to providing a layer, the mounting bracket is also brazed on the other surface on the brazing material side, so that it is composed of a four-layer material that is further clad. For this reason, there exists a problem that cost becomes high in manufacturing, On the other hand, if the said intermediate | middle layer is abbreviate | omitted, there exists a problem that brazability will be impaired.

  The present invention has been made in view of such problems, and is a high-strength material after brazing, and achieves excellent brazing properties on both the brazing material and the core material, as a low-cost material. The present invention provides an aluminum alloy clad material that can be used as a reinforcing material for heat exchangers.

That is, the aluminum alloy clad material for a heat exchanger of the present invention is in mass%, Mn: more than 1.2 to 1.8%, Si: more than 0.8 to 1.4%, Cu: 0.4 to 1. Si: 6-12% is contained on one side of the core material having a composition comprising 0%, Mg: less than 0.05 to 0.2%, and the remainder consisting of Al and inevitable impurities, and the remainder being Al and inevitable impurities A brazing material having a composition consisting of Si: 6-12%, Zn: 0.2-5.0%, the remainder comprising two layers clad with a brazing material composed of Al and unavoidable impurities, The plate thickness is 1.0 to 3.5 mm, and the clad rate of the brazing material is 5 to 15%.
The aluminum alloy clad material for a heat exchanger of the present invention is used as a structural material of a heat exchanger and assembled by brazing. As the use location, it can be used for a reinforcing material such as a side support or a header plate.

Below, the composition etc. which are prescribed | regulated by this invention are demonstrated.
(1) Core material composition (mass%)
Mn: more than 1.2 to 1.8%
Mn has the effect | action which improves an intensity | strength by making it dissolve in a core material base, or disperse | distributes as an Al-Mn type compound, and improves an intensity | strength. However, if it is 1.2% or less, the effect is insufficient. On the other hand, if it is more than 1.8%, the rolling workability is lowered due to the formation of a coarse Al-Mn compound, or the workability of the clad material Decreases. Therefore, the Mn content is set within the above range. For the same reason as described above, the desirable lower limit is 1.4% and the desirable upper limit is 1.6%.

Si: more than 0.8 to 1.4%
Even when Si is used alone, it is dissolved in the matrix to improve the strength. Furthermore, by coexisting with Mn, it becomes an Al—Mn—Si based compound and is dispersed in the substrate to improve the strength. However, if it is 0.8% or less, the effect of improving the strength is poor. On the other hand, if it is more than 1.4%, the melting point of the core material is lowered, so the content is set in the above range. For the same reason as described above, the desirable upper limit is 1.2%.

Cu: 0.4 to 1.0%
Cu is dissolved in the matrix to improve the strength. However, if it is less than 0.4%, the effect is not sufficient. On the other hand, if it exceeds 1.0%, the melting point is lowered and the melting point of the core material is lowered. Therefore, the content is set in the above range. For the same reason as described above, the desirable lower limit is 0.6%, and the desirable upper limit is 0.8%.

Mg: 0.05 to less than 0.2% Mg is dissolved in the matrix to improve the strength, and coexist with Si to improve the material strength by Al-Mg-Si aging precipitation after brazing. . However, if it is less than 0.05%, strength improvement cannot be expected, and if it exceeds 0.2%, it diffuses to the brazing material side during brazing and reacts with the flux to inhibit brazing, so its content Is defined in the above range. For the same reason as described above, a desirable lower limit is 0.1%.

(2) Brazing material composition (mass%)
Si: 6-12%
As the Al—Si brazing material or the Al—Si—Zn brazing material, Si content in the above range is required.

Zn: 0.2-5.0%
Zn is dissolved in the matrix and has the effect of lowering the potential of the brazing material. In particular, when this clad material is used as a reinforcing material for a capacitor, the necessity for the corrosion environment increases due to the influence of the snow melting agent and the like. Further, when the plate thickness is thin, more corrosion resistance is required, so addition of Zn is necessary. For these reasons, Zn is contained in the brazing material as desired. However, when used in capacitors with severe corrosive environments, the corrosion resistance is not sufficient if it is less than 0.2%, while the corrosion of the brazing filler metal layer becomes significant if it exceeds 5%. Determine. For the same reason, the desirable lower limit is 0.5% and the desirable upper limit is 3%.

Clad material plate thickness: 1.0-3.5mm
Heat exchangers vary from relatively small heater cores to large radiators. A small heat exchanger such as a heater core may have a thickness of 1.0 mm for weight reduction. A large heat exchanger such as a radiator or an intercooler or a heat exchanger with high internal pressure requires a thick material. And if the clad material plate thickness is less than 1.0 mm, the effect as a reinforcing material cannot be obtained. On the other hand, even if it is thicker than 3.5 mm, the effect as a reinforcing material does not increase. The thickness is determined within the above range.

Cladding rate: 5-15%
The brazing material needs to have a thickness for joining with other members and maintaining corrosion resistance. When the plate thickness is thin, a clad rate of 10 to 15% is appropriate for the brazing material, while when the plate thickness is thick, a clad rate of 5 to 10% is appropriate. When the plate thickness is thin and the cladding ratio is lower than 5%, the brazing material for joining is not sufficient, and the thickness of the brazing material as a sacrificial material for the core material is not sufficient. On the other hand, when the clad rate is higher than 15%, the core material is thin, so that the strength is not sufficient. When the clad material is thick, the brazing material becomes excessive, and erosion of other members due to brazing becomes remarkable. For these reasons, the cladding ratio of the brazing material is set within the above range.

  The aluminum alloy clad material for heat exchanger of the present invention is in mass%, Mn: more than 1.2 to 1.8%, Si: more than 0.8 to 1.4%, Cu: 0.4 to 1.0% Mg: 0.05 to less than 0.2%, the remainder of the core material composed of Al and unavoidable impurities on one side, Si: 6 to 12%, the remainder consisting of Al and unavoidable impurities Brazing material of composition or Si: 6-12%, Zn: 0.2-5.0%, the remainder consists of two layers clad with a brazing material of a composition consisting of Al and unavoidable impurities, and the overall plate thickness Is 1.0 to 3.5 mm and the clad rate of the brazing material is 5 to 15%, so that high strength can be obtained without impairing the brazing property, and the reinforcing material for the heat exchanger assembled by brazing It can use suitably as.

  A core material and a brazing material adjusted to have the composition of the present invention are prepared. The core material and the brazing material can be produced by a conventional method. For example, an aluminum alloy having a predetermined component is melted, and an aluminum alloy plate having a predetermined thickness is formed by hot rolling. In the manufacturing process, it is possible to appropriately perform heat treatment such as homogenization or annealing. The aluminum alloy plate may be produced by continuous casting.

The core material and the brazing material are clad so that the clad rate of the brazing material is 5 to 15% and the overall plate thickness is 1.0 to 3.5 mm. The clad is usually performed by clad rolling (hot rolling and cold rolling), but the present invention is not limited to this.
The obtained aluminum alloy clad material is processed into an appropriate shape as needed, assembled with other members constituting the heat exchanger, and subjected to brazing. In the heat exchanger 1 shown in FIG. 1, the aluminum alloy clad material of the present invention is used for the reinforcing material 2 as a side support, and the heat exchanger 1 is assembled by being assembled with other tubes 3, fins 4, header plates 5, and the like. Constitute. The brazing conditions are not particularly limited as the present invention. For example, a fluoride-based non-corrosive flux is applied to a structure assembled as a member or as a radiator core, and brazing heat treatment is performed in an inert gas atmosphere or the like.
In the obtained heat exchanger 1, the reinforcing material 2 is brazed well, and the reinforcing material has high strength.

An aluminum alloy adjusted to the composition shown in Tables 1 and 2 is melted as a core material and a brazing material by a conventional method, and the brazing alloy is heated to a predetermined thickness, and the brazing alloy and the core material are used. A clad material was produced by hot rolling in combination with an alloy. Each clad material was cold rolled to a predetermined thickness (1.6 mm) at a clad rate shown in Table 3, and heat treated under the condition of 380 ° × 12 h to obtain an O material.
About the obtained test material, the evaluation test was done on the following conditions about the intensity | strength and brazing property after brazing, and the evaluation result was shown in Table 3.

[Tensile test]
For the strength after brazing, a tensile test according to JISZ2201 was performed on a material obtained by heating an aluminum alloy clad material at 600 ° C. for 5 minutes in an inert gas atmosphere.

[Brassability]
For brazing on the brazing material side, a sample with a width of 30 mm and a length of 60 mm is cut out from an aluminum alloy clad material, and a JIS 3003 alloy plate with a thickness of 1.0 mm is cut out into a width of 20 mm and a length of 50 mm from the brazing material side. The test was carried out using an inverted T-shaped test piece that was assembled perpendicularly to the aluminum alloy clad material.
The brazing property on the core material side is obtained by cutting a sample having a width of 30 mm and a length of 60 mm from an aluminum alloy clad material, using the core material side as an upper surface, JIS3003 alloy as a core material, and JIS4343 alloy on both surfaces at a ratio of 5%. A clad brazing sheet having a thickness of 1.0 mm was cut into a width of 20 mm and a length of 50 mm, and an inverted T-shaped test piece was assembled perpendicularly to an aluminum alloy clad material.

The evaluation of brazing was evaluated as ◎ for those with good fillet formation and no brazing, ◯ for those with a small fillet but no brazing, and x for those with small fillets and brazing. .
As shown in Table 3 below, the test material of the present invention has high tensile strength and excellent brazing properties on both the brazing material side and the core material side.

  As mentioned above, although this invention was demonstrated based on the said embodiment and Example, this invention is not limited to the content of the manufacturing method etc. which were described in these, It can change within the scope of the present invention. is there.

It is a figure which shows the heat exchanger using the clad material of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Reinforcement material 3 Tube 4 Fin 5 Header plate

Claims (1)

  In mass%, Mn: more than 1.2 to 1.8%, Si: more than 0.8 to 1.4%, Cu: 0.4 to 1.0%, Mg: less than 0.05 to 0.2% On the one side of the core material composed of Al and unavoidable impurities, and the balance containing Si and 6 to 12% of the brazing material or Si: 6 to 12%. Zn: It is composed of two layers clad with a brazing material containing 0.2 to 5.0% and the remainder consisting of Al and inevitable impurities, and the overall plate thickness is 1.0 to 3.5 mm. The aluminum alloy clad material for heat exchangers is characterized in that the clad rate of the heat exchanger is 5 to 15%.

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