JPH0790454A - Aluminum alloy brazing sheet for heat exchanger and method for manufacturing aluminum alloy heat exchanger - Google Patents

Abstract

(57) [Summary] [Constitution] S of brazing filler metal exceeding 7.0 wt% and 12.0 wt% or less
i, containing more than 0.1 wt% and not more than 8.0 wt% Cu, 0.5
Zn over 6.0 wt% over wt%, 0.3 over 0.002 wt%
In of less than wt%, Sn of more than 0.002 wt% and less than 0.3 wt%
Aluminum alloy containing one or more of the above, and the core material is more than 0.6 wt% and 1.2 wt% or less of Si, 0.05
An aluminum alloy containing Mn in an amount of more than 2.0 wt% and less than 2.0 wt% and a sacrificial material containing Z in an amount of more than 0.5 wt% and less than 6.0 wt%
n, more than 0.002 wt% and 0.3 wt% or less In, 0.002 wt%
An aluminum alloy brazing sheet comprising an aluminum alloy containing one or more Sn of more than 0.3 wt% and less than 0.3 wt%. [Effect] The aluminum alloy material of the present invention has high strength, excellent corrosion resistance, no melting at the time of brazing, and when a heat exchanger is manufactured, it can be reduced in size and weight, and has an outstanding industrial effect. is there.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy brazing sheet for a heat exchanger used as a constituent member of a heat exchanger for automobiles and the like and a method for producing an aluminum alloy heat exchanger using the brazing sheet. Yes, in more detail, it is used as a tube material by electric sewing etc. or as a header material as it is, it has high strength after brazing, excellent external and internal corrosion resistance after being used as a heat exchanger member, and The present invention relates to an aluminum alloy brazing sheet for a heat exchanger having excellent heat exchange performance as a heat exchanger, and a method for manufacturing an aluminum alloy heat exchanger using the brazing sheet.

[0002]

2. Description of the Related Art A heat exchanger such as a radiator has a plurality of flat tubes (1) integrally formed with corrugated thin fins (2) as shown in FIG. Both ends of the flat tube (1) are opened in the space formed by the header (3) and the tank (4), and the flat tube (1) is passed through from the space on the side of one tank to a high temperature. The refrigerant is sent to the space on the side of the other tank (4), and heat exchanged in the tubes (1) and fins (2) to circulate the refrigerant that has become low temperature.

The tube material and header material of such a heat exchanger are, for example, JIS3003 (Al-0.15 wt% Cu).
-1.1 wt% Mn) alloy as a core material, and JIS707 as an inner lining material on the inner side of the core material, that is, the side that is constantly in contact with the refrigerant.
2 (Al-1 wt% Zn) alloy, and a brazing sheet in which a brazing material such as JIS4045 (Al-10 wt% Si) alloy is usually clad outside the core material, and fins are corrugated. It is integrally assembled with other members by brazing. As a brazing method, a flux brazing method, a Nocolock brazing method using a non-corrosive flux, or the like is performed, and brazing is performed by heating to a temperature near 600 ° C.

By the way, in recent years, heat exchangers have been in the direction of weight reduction and downsizing, and therefore, thinning of materials has been desired. However, when the thickness is reduced by the conventional method, many problems occur.

First, the phenomenon that the fins buckle during brazing, or the wax diffuses into the fins and melts, is more likely to occur as the fins become thinner.
μm and brazing sheet fins are limited to 100 μm. When buckling occurs, the ventilation efficiency increases and the thermal efficiency of the heat exchanger decreases. In addition, the heat exchange performance of the heat exchanger is
It is determined by the thermal conductivity of the fin, and the intermetallic compound precipitated in the fin during brazing heat re-dissolves, but the higher the heating temperature, the larger the solid solution limit of alloying elements and the greater the diffusion rate. Therefore, re-dissolution becomes easy to proceed.
As a result, the heat conductivity of the fins is greatly reduced, and the heat exchange performance of the heat exchanger is also deteriorated.

Further, in order to solve the problem that the heat efficiency of the heat exchanger decreases as the material becomes thinner, fins having excellent thermal conductivity have been developed. For example, a fin material made of Al--Zr alloy has been developed. Proposed. However, such a fin material has low strength and has a problem that the brazing material is likely to diffuse when the brazing material is heated.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of such a situation, the present invention provides an aluminum alloy brazing sheet for a heat exchanger, which is excellent in strength and corrosion resistance after brazing, and is also excellent in heat efficiency of the heat exchanger, and We have developed a manufacturing method that can reduce the size and weight of an aluminum alloy heat exchanger and improve its thermal efficiency. That is, a tube material made of a core alloy, a sacrificial alloy, and a brazing alloy according to the present invention is combined with a fin material that has been conventionally used as a heat exchanger, and brazing is performed at a temperature lower than the conventional 600 ° C. The above-mentioned effect is exhibited when this is done.

That is, the first brazing sheet of the present invention
Is a three-layer aluminum alloy brazing sheet for a heat exchanger in which a brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy and a sacrificial material made of an aluminum alloy is clad on the other side. Si more than 7.0 wt% and less than 12.0 wt%, 0.1
Contains more than 8.0 wt% Cu and more than 0.5 wt%
% Zn over 6.0 wt% and under 0.3 wt% over 0.002 wt%
% Or less In, 0.002 wt% or more and 0.3 wt% or less Sn of 1 type or 2 or more are contained, and the balance is aluminum alloy consisting of aluminum and unavoidable impurities. Si less than wt%, more than 0.05 wt%
An aluminum alloy containing 2.0% by weight or less of Mn and the balance of aluminum and unavoidable impurities.
Zn over 0.5 wt% and under 6.0 wt%, over 0.002 wt%
An aluminum alloy comprising 0.3% by weight or less of In and 0.002% by weight or more and 0.3% by weight or less of Sn, and an aluminum alloy comprising the balance aluminum and inevitable impurities. It is a brazing sheet.

The second of the brazing sheets of the present invention is:
In a three-layer aluminum alloy brazing sheet for a heat exchanger, in which a brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy and a sacrificial material made of an aluminum alloy is clad on the other side, the brazing material is 7.0 wt. %, 12.0 wt% or less Si, 0.1 wt% to 8.0 wt% or less Cu, further 0.5 wt% to 6.0 wt% Zn, 0.002 wt% to 0.3 wt% In, 1 of Sn over 0.002wt% and under 0.3wt%
Aluminum alloy containing at least one of the above, with the balance aluminum and unavoidable impurities, with a core material of 0.6
Si of more than 1.2 wt% and more than wt%, 2.0 wt of more than 0.05 wt%
% Or less of Mn, more than 0.05 wt% and 0.5 wt%
Cu below 0.03 wt% over 0.5 wt% Mg below 0.03
Cr of more than 0.3% by weight and over 0.3% by weight of 0.03% by weight
% Or less Zr, 0.03 wt% or more and 0.3 wt% or less Ti, 0.
An aluminum alloy containing more than 03 wt% and less than 1.5 wt% Ni, one or more, and the balance aluminum and unavoidable impurities. The sacrificial material exceeds 0.5 wt%.
It contains one or two or more of Zn of 6.0 wt% or less, In of more than 0.002 wt% and 0.3 wt% or less, and Sn of 0.002 wt% or more and 0.3 wt% or less, with the balance aluminum and inevitable impurities. Is an aluminum alloy brazing sheet.

The third brazing sheet of the present invention is:
In a three-layer aluminum alloy brazing sheet for a heat exchanger, in which a brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy and a sacrificial material made of an aluminum alloy is clad on the other side, the brazing material is 7.0 wt. %, 12.0 wt% or less Si, 0.1 wt% to 8.0 wt% or less Cu, further 0.5 wt% to 6.0 wt% Zn, 0.002 wt% to 0.3 wt% In, 1 of Sn over 0.002wt% and under 0.3wt%
Aluminum alloy containing at least one of the above, with the balance aluminum and unavoidable impurities, with a core material of 0.6
Si of more than 1.2 wt% and more than wt%, 2.0 wt of more than 0.05 wt%
% Or less of Mn, aluminum alloy consisting of balance aluminum and unavoidable impurities, and 0.5 wt% of sacrificial material
% Over 6.0 wt% Zn, 0.002 wt% over 0.3 wt
% Or less of In, 0.002 wt% or more and 0.3 wt% or less of Sn, and one or more kinds of Sn are contained, and further 0.05 wt% or more and 2.5 wt% or less of Mg, 0.05 wt% or more and 1.6 wt% or less. The aluminum alloy brazing sheet is characterized in that it is an aluminum alloy containing one or two of Mn, and the balance aluminum and unavoidable impurities.

The fourth brazing sheet of the present invention is:
In a three-layer aluminum alloy brazing sheet for a heat exchanger, in which a brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy and a sacrificial material made of an aluminum alloy is clad on the other side, the brazing material is 7.0 wt. %, 12.0 wt% or less Si, 0.1 wt% to 8.0 wt% or less Cu, further 0.5 wt% to 6.0 wt% Zn, 0.002 wt% to 0.3 wt% In, An aluminum alloy containing 1 or 2 or more of Sn of more than 0.002 wt% and 0.3 wt% or less, with the balance being aluminum and unavoidable impurities, and a core material of 0.6 wt
%, 1.2 wt% or less of Si, 0.05 wt% or more, 2.0 wt%
It contains the following Mn, and more than 0.05 wt% and less than 0.5 wt% Cu, more than 0.03 wt% and less than 0.5 wt% Mg, 0.03 wt
%, 0.3 wt% or less Cr, 0.03 wt% or more, 0.3 wt%
Zr below, 0.03 wt% to over 0.3 wt% Ti, 0.03
An aluminum alloy containing more than 1.5 wt% and less than 1.5 wt% Ni, and the balance aluminum and unavoidable impurities, and the sacrificial material exceeds 0.5 wt%
It contains one or more Zn of 6.0 wt% or less, In of 0.002 wt% or more and 0.3 wt% or less, or Sn of 0.002 wt% or more and 0.3 wt% or less, and further exceeds 0.05 wt% and 2.5 wt%.
% Aluminum or less, and an aluminum alloy brazing sheet containing one or two of more than 0.05 wt% and less than 1.6 wt% Mn, the balance being aluminum and unavoidable impurities. is there.

Further, in the method for producing a heat exchanger of the present invention, when the heat exchanger is produced by the brazing method using the brazing sheet according to any of the above inventions, the brazing heating temperature is higher than 570 ° C and lower than 585 ° C. This is a method for manufacturing an aluminum alloy heat exchanger.

First, the structure of the brazing sheet of the present invention will be described. The aluminum alloy material for a heat exchanger of the present invention is a brazing sheet having a three-layer structure as shown in FIG. That is, a high-strength aluminum alloy is used as a core material (5), a brazing material (6) is provided on one surface of the core material, and a sacrificial material (7) is provided on the other surface. When assembling a heat exchanger using this brazing sheet, the brazing material of the brazing sheet is used on the outside and the sacrificial material is used on the side of the refrigerant passage.

The core material alloy according to the present invention is a high strength alloy and has a high Si content. That is, the core material exceeds 0.6 wt%
Si of 1.2 wt% or less, M of more than 0.05 wt% and 2.0 wt% or less
An aluminum alloy containing n and the balance aluminum and unavoidable impurities, as well as 0.05 wt.
% Cu less than 0.5 wt% and less than 0.03 wt% 0.5 wt%
Mg below 0.03 wt% over 0.3 wt% Cr below 0.03
Zr more than 0.3 wt% and more than 0.3 wt%
% Or less of Ti, and one or more of Ni of more than 0.03 wt% and less than 1.5 wt% are added to the aluminum alloy.

In the present invention, brazing is performed with the brazing temperature in the range of more than 570 ° C and less than 585 ° C. This is because when the brazing temperature is 570 ° C. or lower, the brazing material according to the present invention has a composition that does not melt and cannot be brazed.
Also, when brazing the heat exchanger above 585 ℃,
Since the intermetallic compound precipitated in the fin material is redissolved, the thermal conductivity of the fin is lowered, and the heat efficiency of the heat exchanger is lowered. Therefore, the higher the heating temperature, the larger the solid solution limit of the alloying elements and the higher the diffusion rate, so that the re-solid solution is likely to proceed.Therefore, lowering the brazing temperature improves the thermal conductivity of the fin. Found to be effective, 585
It has been found that if the temperature is not higher than 0 ° C, the re-dissolution rate is low, and the thermal conductivity is not significantly reduced.

Further, by lowering the brazing temperature, the high temperature buckling resistance of the fin is also improved. First, we found that most of the buckling of fins is due to the high temperature creep phenomenon in the fins at high temperatures, and that the fins suddenly occur at temperatures higher than 590 ° C (the fins weaken). Therefore, if the temperature is 585 ° C or lower, buckling due to this will not occur. Furthermore, although there is buckling due to the diffusion of wax in the fin, it was found that the diffusion of wax occurs rapidly around 595 ° C at higher temperatures. Therefore, if the temperature is 585 ° C or less, the diffusion of the wax will be small, and the buckling of the fins will be less likely to occur as a whole.

Therefore, when a heat exchanger is manufactured using the three-layer brazing sheet of the present invention, if the brazing is performed at 585 ° C. or less, the heat conductivity of the fins is improved, that is, the heat efficiency of the heat exchanger is improved. Is improved. It should be noted that lowering the brazing temperature in this way also has the effect of extending the life of the brazing furnace.

Next, the role of each additive element of the core alloy will be described below. Si contributes to the strength improvement. Si is 0.6wt%
In the following cases, the strength improving effect is not sufficient, and if it exceeds 1.2 wt%, a coarse compound is formed in the core material, and if corrosion progresses beyond the sacrificial material layer, the corrosion resistance decreases. That is, if a large amount of Si is added to the core material in order to increase the strength, the corrosion resistance of the refrigerant passage constituting member is sharply lowered. As a result of intensive investigations by the inventors regarding the cause of this corrosion, it is found that Si in the core material diffuses into the sacrificial material layer and that the constituents of the sacrificial material (for example, Zn)
It has been found that the components of the sacrificial material change greatly as compared with those before brazing due to the diffusion into the core material, which causes the sacrificial effect to decrease and the corrosion resistance to decrease. Therefore, Si is 0.6wt
% And 1.2 wt% or less, but stable characteristics are exhibited especially near 0.8 wt%.

Mn is an essential element for distributing the intermetallic compound in the alloy and improving the strength without lowering the corrosion resistance. If the amount is less than 0.05 wt%, it is not sufficient, and if added in excess of 2.0 wt%, the formability deteriorates and the brazing sheet cracks during processing such as assembly.

Cu exists in the alloy in a solid solution state and improves the strength. When Cu is 0.05 wt% or less, the strength improving effect is not sufficient. Considering corrosion resistance, the upper limit of Cu is 0.5wt
% Or less is desirable. Therefore, Cu exceeds 0.5 wt% and 0.5
Although it is less than wt%, stable characteristics are exhibited especially at 0.1 to 0.3 wt%.

Mg is a solid solution in the alloy and Mg ₂ Si
Exists as a fine precipitation phase of and improves the strength. 0.05
If it is less than wt%, there is no effect, and if it exceeds 0.5 wt%, when brazing using a non-corrosive flux, the flux reacts with Mg and brazing becomes impossible.

Cr, Zr, and Ti all have the function of forming a fine intermetallic compound and improving the strength of the alloy.
However, if 0.03wt% or less is not effective, 0.3wt%
If added in excess of%, the formability will decrease and the brazing sheet will crack during processing such as assembly.

Ni also has the function of forming a fine intermetallic compound and improving the strength of the alloy. However, if it is less than 0.03 wt%, there is no effect, and if it is added in excess of 1.5 wt%, the formability deteriorates and the brazing sheet cracks during processing such as assembly.

The above are the components of the core alloy of the present invention.
Fe is a typical element of unavoidable impurities.
May be contained as long as it is 1.2 wt% or less.
Further, elements other than the above, such as B added for refining the structure of the ingot, may be contained if the content is 0.05 wt% or less.

Next, the brazing alloy of the present invention will be described. When the conventional tube material and fin material were combined and brazed at around 600 ° C, it was extremely difficult to maintain the tube material at high strength and further improve the heat efficiency of the heat exchanger. The present invention solves this problem by combining a tube material made of a core material alloy, a sacrificial material alloy, and a brazing material alloy according to the present invention with a fin material that has been conventionally used, as a heat exchanger. It is effective when brazing at a temperature lower than ℃.

That is, various studies have been conducted on the improvement of the heat efficiency of the heat exchanger, and the tube material made of the core material alloy according to the present invention, the sacrificial material alloy, and the brazing material conventionally used is combined with the conventional fin material. If the conventional 600
At a brazing heat temperature near ℃, the re-solution of the intermetallic compound that had been precipitated in the aluminum alloy of the fin material is likely to proceed, and as a result, the thermal conductivity of the fin material decreases, The problem remains that the heat efficiency of the exchanger is low.

Therefore, in the present invention, Cu is added to the brazing alloy to lower the melting point as compared with the conventional brazing material, so that brazing can be sufficiently performed at a temperature lower than the conventional one. Further, the present invention is characterized by adding one or more of Zn, In and Sn in order to prevent deterioration of external corrosion resistance due to addition of Cu. As described above, if the brazing sheet clad with the brazing alloy of the present invention was brazed at a temperature of around 600 ° C., it can be brazed at a temperature of 585 ° C. or lower. Is improved, and the heat efficiency as a heat exchanger is improved as compared with the conventional one. In this way, an alloy having a lower brazing temperature than the conventional brazing alloy was developed.

The role of each element of the brazing alloy and the reason for the limitation will be described below. Here, the alloy composition of the brazing filler metal according to the present invention has a brazing filler metal content of more than 7.0 wt% and not more than 12.0 wt% Si,
Contains more than 0.1 wt% and less than 8.0 wt% Cu, 0.5 wt%
Over 0.006 wt% Zn, over 0.002 wt% 0.3 wt%
It is an aluminum alloy containing the following In and one or more kinds of Sn in an amount of more than 0.002 wt% and not more than 0.3 wt% and the balance aluminum and unavoidable impurities. The reasons for limitation are described below.

The addition of Si lowers the melting point of the alloy, but if the amount is 7.0 wt% or less, the melting point is not sufficiently lowered and brazing cannot be performed at a temperature of 585 ° C. or less. Furthermore, the amount is 12.0 wt%
On the other hand, if the temperature exceeds 580 ° C, the melting point rises, so that brazing cannot be performed at temperatures below 585 ° C.

The addition of Cu lowers the melting point of the alloy and improves the wax flowability. If the amount of Cu is 0.1 wt% or less, the brazing property improving effect is not sufficient, and if the amount exceeds 8.0 wt%, the melting point of the alloy decreases and the brazing property stabilizes, but the potential of the brazing material becomes noble. Too much, the core material will be preferentially corroded,
Corrosion resistance decreases. In addition, the rolling workability of the alloy decreases,
It cannot be manufactured as a brazing sheet for heat exchangers. Therefore, although Cu is more than 0.1 wt% and 8.0 wt% or less, stable characteristics are exhibited particularly at 0.5 to 3.5 wt%.

The addition of Zn lowers the melting point of the alloy. Furthermore, in the brazing filler metal alloy containing Cu as in the present invention, the occurrence of swelling due to external corrosion can be suppressed, but the potential of the brazing filler metal becomes nobler than that of the core material, and the external corrosion progresses in a pit-like manner and its speed is increased. There is a problem that is fast. The addition of Zn lowers the potential of the brazing material, brings the potential of the brazing material closer to that of the core material, and improves the corrosion resistance. However, when the amount exceeds 6.0 wt%, the self-corrosion resistance of the brazing material is deteriorated and the rolling workability of the alloy is deteriorated, which makes it unsuitable as a brazing material used for a brazing sheet for a heat exchanger.

In and Sn also make the electric potential of the brazing material base and improve the corrosion resistance of the refrigerant passage constituting member. The amount is 0.002
If it is less than wt%, the effect is not sufficient, and if it exceeds 0.3 wt%, the rolling workability of the alloy is deteriorated.

The additive elements of the brazing filler metal according to the present invention are as described above, but Fe can be contained as an unavoidable impurity if it is 1.0 wt% or less. However, Fe forms an intermetallic compound when the brazing solidifies, which is the starting point of corrosion. Therefore, the Fe content is preferably 0.5 wt% or less. Fe
Other inevitable impurities other than 0.05
You may contain if it is less than wt%.

The role of each additional element of the sacrificial alloy will be described.
When a sacrificial alloy as in the present invention and a high Si-added core alloy are combined, Si added to the core alloy diffuses into the sacrificial layer during brazing, canceling the sacrificial effect of the sacrificial material. Will end up. Therefore, it is conceivable to increase Zn in the sacrificial material, but if Zn is increased, the melting point of the sacrificial material is lowered and the sacrificial material is melted during brazing. However, since the low melting point brazing material is used in the present invention, it is possible to increase Si of the core alloy and increase Zn of the sacrificial alloy.

That is, the sacrificial material according to the present invention includes Zn of more than 0.5 wt% and 6.0 wt% or less, In of more than 0.002 wt% and 0.3 wt% or less, and Sn of more than 0.002 wt% and 0.3 wt% or less. An aluminum alloy containing one or more kinds and the balance aluminum and unavoidable impurities, or an aluminum alloy containing 0.05% by weight or more and 2.5% by weight or less, or 0.05% by weight or more and 1.6% by weight or less Mn. It is an aluminum alloy with one or two added.

The addition of Zn gives the alloy a sacrificial effect. However, if the amount is 0.5 wt% or less, the effect is not sufficient, and if the amount exceeds 6.0 wt%, the melting point decreases, and even if the brazing alloy according to the present invention is used, it melts during brazing.

The addition of In and Sn also gives a sacrificial effect to the alloy. However, if the amount is less than 0.002 wt%, the effect is not sufficient, and if the amount exceeds 0.3 wt%, the rolling workability of the alloy is deteriorated and it becomes unsuitable as a sacrificial material used for a brazing sheet of three-layer material.

The addition of Mg increases the strength of the sacrificial material and improves the strength of the entire material. However, if the amount is less than 0.05 wt%, there is no effect, and if it exceeds 2.5 wt%, the melting point decreases, and even if the brazing alloy according to the present invention is used, it will melt during brazing.

The addition of Mn also increases the strength of the sacrificial material and improves the strength of the entire material. However, if the amount is less than 0.05 wt%, there is no effect, and if it exceeds 1.6 wt%, the rolling workability of the alloy deteriorates, and it becomes unsuitable as a sacrificial material used for a brazing sheet of three-layer material.

Although the additive elements of the sacrificial material of the present invention are as described above, Si can be contained as an unavoidable impurity if it is 0.5 wt% or less, but 0.1 wt% or less is preferable. F
e can be contained if it is 0.8 wt% or less, but 0.1 wt%
The following is desirable. Elements other than the above, such as Cr, Zr, and Ti for improving strength, may be contained as impurity elements as long as the content is 0.05 wt% or less.

The brazing sheet of the present invention is a three-layer material having the above alloy composition, and the brazing material and the sacrificial material each have a thickness of usually about 30 μm. Since the coverage varies depending on the plate thickness of the member used, it is not limited to this value.

The above-mentioned three-layer material of the present invention is used for a heat exchanger by being made into a tube by electric sewing or brazing as a header material as it is.

Here, the brazing conditions of the present invention are limited in temperature as described above, but other conditions may be almost the same as the conventional one. That is, it is not particularly limited as long as it is a flux brazing method, a nocolock brazing method using a non-corrosive flux, or the like. Assembling before brazing, cleaning, and flux coating depending on the case may be performed as usual. In this case, the flux can be brazed in the temperature range of the present invention even if a cesium-based flux is used.

In the present invention, the steps after heating are not particularly limited. Processes such as aging treatment, flux removal, and painting may be performed as is conventionally done.

As a method of brazing at a temperature lower than the normal brazing temperature, there is known a method of brazing at a temperature of about 500 ° C., which is called low temperature brazing. This method has a problem that the brazing material is easily corroded after brazing because an Al-Zn alloy or Zn alloy containing 20% or more of Zn is usually used as a brazing material. not being used. Furthermore, Al
In a Zn-based alloy, if the amount of Zn added exceeds 8%, the rolling property becomes very poor, so it is impossible to manufacture a brazing sheet by combined rolling, and a brazing sheet for low-temperature brazing is industrially stable. The manufacturing method to supply is not established. Therefore, brazing must be used for placing or the like, and the types of members that can be manufactured are limited. However, the inventors have found that it is possible to improve the characteristics of the heat exchanger even at a brazing temperature of 585 ° C. or lower, which is much higher than the low temperature brazing, and developed the brazing sheet of the present invention. Is.

Further, there is an alloy known as a brazing aluminum alloy having a low melting point in the past (for example, JP-A-3-
57588 publication). These are mainly developed for brazing castings, and contain a large amount of Cu or add a large amount of Zn as described above, so that they are cracked when rolling is performed. There was a problem and the brazing sheet could not be manufactured. If it cannot be used as a brazing sheet, it is not practical for industrially manufacturing a heat exchanger. The present invention has developed a brazing sheet that solves these problems.

[0047]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 An aluminum alloy brazing material having the composition shown in Tables 1 to 3 and a sacrificial material were clad on both sides of an aluminum alloy core material having the composition shown in Tables 4 to 6 to form aluminum. Plate thickness for alloy tube material
0.25 mm three-layer brazing sheet plates 1 to 40 and A to G were manufactured by a usual method. At this time, the clad ratio of the brazing material is 10% and the clad ratio of the sacrificial material is 15%. Further, Fe and Si are contained as impurity elements in the sacrificial material, respectively.
It is contained within the range of 01 to 0.2 wt%. These plate materials,
Heating was performed in N ₂ gas under the conditions shown in Tables 7 and 8.

The obtained plate material was subjected to a tensile test and an internal corrosion resistance test with the brazing material part as the outer side and the sacrificial layer part as the inner side. As for the brazing property, the brazing property was visually evaluated by a T-shaped fluidity test. Regarding the rollability, the condition of the rolled plate during cold rolling was visually observed to evaluate whether or not there were rolling defects such as edge cracks, rough skin, and plate breaks. Further, regarding the melting when the brazing heat is applied, the plate was visually observed after heating, and the presence or absence thereof was evaluated.

For the internal corrosion resistance test, a plate material with the brazing material masked is dipped in tap water containing 10 ppm of Cu ²⁺ ions for 5 months and subjected to a cycle corrosion test at 80 ° C. × 8 hours and room temperature × 16 hours. The pit depth generated on the surface of the sacrificial material was determined by the depth of focus method using an optical microscope. And these results are shown in Tables 7-8.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

[Table 5]

[0056]

[Table 6]

[0057]

[Table 7]

[0058]

[Table 8]

From Tables 7 and 8, Comparative Examples A and B had different compositions of the core material and the sacrificial material according to the present invention, and the brazing heat was applied at 575 ° C., but they were melted. In Comparative Example C, the sacrificial material did not contain any of Zn, In, and Sn, and the internal corrosion resistance was lowered, and through holes were formed. Comparative Example D is outside the range of the brazing alloy according to the present invention,
Since the wax does not melt below 585 ° C, heating was performed at 600 ° C, but the sacrificial material melted. In Comparative Example E, Cu and Zn, which are brazing alloys, were added in a larger amount than the range of the present invention, and the brazing sheet could not be manufactured because it cracked during rolling. Conventional example F has a plate thickness of 0.4
The one used in mm has a thin plate thickness of 0.25 mm as described above, and is inferior in strength and corrosion resistance to the present invention. Further, Conventional Example G is an example in which the core material contains more Cu than Conventional Example F, but is inferior in corrosion resistance.

From the above evaluation results, the aluminum brazing sheet according to the method of the present invention has the same internal corrosion resistance as the conventional one, and the strength, brazing property and rollability are slightly improved as compared with the conventional one or the conventional one. is there. Therefore, when using it as a brazing sheet,
There is no problem.

Next, as Example 2, the brazing sheet according to the present invention was evaluated for brazing property and thermal efficiency when used as a heat exchanger in combination with fins.

Example 2 An aluminum alloy fin material having a plate thickness of 0.06 mm and made of a bare material having a composition shown in Nos. 1 and 2 of Table 9 and compositions shown in Nos. 3 to 21 shown in Tables 9 and 10 10% of brazing filler metal having the composition shown in No. 3 to 21 on one side of the core material
Clad with the thickness of
As shown in Table 11, the radiator shown in FIG. 1 was assembled by combining an electric resistance welded tube material having a plate thickness of 0.3 mm clad with a thickness of 0.3% and a header plate material having a plate thickness of 1 mm having the same structure. That is, member numbers No. 3, No. 4, No. 6-
The sacrificial material composition of No. 16 is Al-4wt% Zn-2wt% Mg alloy, the material of No. 5 is Al-2wt% Zn, and the material of No. 17 is Al-2wt% Zn-2wt% Mg. alloy,
The member No. 18 has an Al-4 wt% Zn alloy, the member No. 19 has an Al-2 wt% Mg-0.09 wt% Sn alloy, and the member No. 20 has an Al-1 wt% Zn alloy, Material No. 21 is Al-6wt% Zn-2.4wt% Mg
It is an alloy.

Here, as the tube material, a coil-shaped plate material having a plate thickness of 0.3 mm shown in Table 9 and Table 10 is manufactured by a usual method,
This coiled plate was slittered to a width of 35.0 mm according to the size of the electric resistance welded pipe. Then, this strip was processed into an electric resistance welded pipe having a width of 16.0 and a thickness of 2.2 mm by using an electric resistance welded pipe manufacturing apparatus. A coil-shaped plate material having the same structure and a plate thickness of 1.0 mm was slitted to a width of 60 mm to form a strip for a header plate.

The assembled radiator was coated with a 10% concentration solution of a flux obtained by mixing 3% of cesium flux with potassium fluoride flux and exposed in N ₂ gas.
The brazing was performed by heating under 11 brazing conditions. With respect to the obtained radiator, it was examined by observing the appearance whether or not the crushed condition of the fins and tubes and the brazing property for forming the fillet were good. The results are shown in Table 11. In addition, the heat efficiency of the normally brazed heat exchanger was investigated. The thermal efficiency was measured according to JIS D 1618 (Testing method for air conditioners for automobiles), and Table 11 shows the rate of improvement with respect to the thermal efficiency of the conventional heat exchanger (of (19) in Table 11). .

[0065]

[Table 9]

[0066]

[Table 10]

[0067]

[Table 11]

[0068]

[Table 12]

In the method of the present invention, the heat exchanger is manufactured without the fins being crushed, and the manufactured radiator is excellent in thermal efficiency.

[0070]

INDUSTRIAL APPLICABILITY As described above, the aluminum alloy material of the present invention has high strength and excellent corrosion resistance, does not melt when brazing, and when a heat exchanger is manufactured, it can be made compact and lightweight, which is remarkable in industry. It has a great effect.

[Brief description of drawings]

FIG. 1 is a perspective view, partly in section, showing a radiator.

FIG. 2 is a cross-sectional view showing the structure of a brazing sheet.

[Explanation of symbols]

 1 Flat tube 2 Fins 3 Header 4 Tank 5 Core material 6 Brazing material 7 Sacrificial material

Claims (5)

[Claims] 1. A brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy, and a sacrificial material made of an aluminum alloy is clad on the other side.
Aluminum alloy brazing sheets for heat exchangers with a layered structure containing more than 7.0 wt% and 12.0 wt% or less of brazing filler metal
i, containing Cu of more than 0.1 wt% and less than 8.0 wt%, Zn of more than 0.5 wt% and less than 6.0 wt%, In of more than 0.002 wt% and less than 0.3 wt%, and more than 0.002 wt% of 0.3 wt% An aluminum alloy containing one or more of the following Sn and the balance aluminum and unavoidable impurities, and the core material is more than 0.6 wt% and 1.2 wt% or less of Si, 0.05 wt%
% And 2.0 wt% or less of Mn, and an aluminum alloy containing the balance aluminum and unavoidable impurities,
Zn of more than 0.5 wt% and less than 6.0 wt% of sacrificial material, 0.002 wt
%, 0.3 wt% or less In, 0.002 wt% or more 0.3 wt%
% Or less of Sn, and an aluminum alloy brazing sheet comprising an aluminum alloy containing the balance aluminum and unavoidable impurities. 2. A brazing material made of an aluminum alloy is clad on one surface of a core material made of an aluminum alloy, and a sacrificial material made of an aluminum alloy is clad on the other surface.
Aluminum alloy brazing sheets for heat exchangers with a layered structure containing more than 7.0 wt% and 12.0 wt% or less of brazing filler metal
i, containing Cu of more than 0.1 wt% and less than 8.0 wt%, Zn of more than 0.5 wt% and less than 6.0 wt%, In of more than 0.002 wt% and less than 0.3 wt%, and more than 0.002 wt% of 0.3 wt% An aluminum alloy containing one or more of the following Sn and the balance aluminum and unavoidable impurities, and the core material is more than 0.6 wt% and 1.2 wt% or less of Si, 0.05 wt%
%, 2.0% by weight or less of Mn, and 0.05% by weight
Over 0.5 wt% and less than Cu, 0.03 wt% over 0.5 wt% and less Mg, 0.03 wt% over 0.3 wt% and less Cr, 0.03 wt
% Over 0.3 wt% Zr, 0.03 wt% over 0.3 wt%
The following sacrificial material is used as an aluminum alloy containing one or more of the following Ti and more than 0.03 wt% and less than 1.5 wt% Ni, and the balance aluminum and unavoidable impurities.
Zn over 0.5 wt% and under 6.0 wt%, over 0.002 wt%
An aluminum alloy comprising 0.3% by weight or less of In and 0.002% by weight or more and 0.3% by weight or less of Sn, and an aluminum alloy comprising the balance aluminum and inevitable impurities. Brazing sheet. 3. A brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy, and a sacrificial material made of an aluminum alloy is clad on the other side.
Aluminum alloy brazing sheets for heat exchangers with a layered structure containing more than 7.0 wt% and 12.0 wt% or less of brazing filler metal
i, containing Cu of more than 0.1 wt% and less than 8.0 wt%, Zn of more than 0.5 wt% and less than 6.0 wt%, In of more than 0.002 wt% and less than 0.3 wt%, and more than 0.002 wt% of 0.3 wt% An aluminum alloy containing one or more of the following Sn and the balance aluminum and unavoidable impurities, and the core material is more than 0.6 wt% and 1.2 wt% or less of Si, 0.05 wt%
% And 2.0 wt% or less of Mn, and an aluminum alloy containing the balance aluminum and unavoidable impurities,
Zn of more than 0.5 wt% and less than 6.0 wt% of sacrificial material, 0.002 wt
%, 0.3 wt% or less In, 0.002 wt% or more 0.3 wt%
% Or less of Sn, containing 1 or 2 or more, and more than 0.05 wt% Mg less than 2.5 wt% and more than 0.05 wt%
An aluminum alloy brazing sheet comprising one or two kinds of Mn of 1.6 wt% or less, the balance being aluminum and unavoidable impurities. 4. A brazing material made of an aluminum alloy is clad on one side of a core material made of an aluminum alloy, and a sacrificial material made of an aluminum alloy is clad on the other side.
Aluminum alloy brazing sheets for heat exchangers with a layered structure containing more than 7.0 wt% and 12.0 wt% or less of brazing filler metal
i, containing Cu of more than 0.1 wt% and less than 8.0 wt%, Zn of more than 0.5 wt% and less than 6.0 wt%, In of more than 0.002 wt% and less than 0.3 wt%, and more than 0.002 wt% of 0.3 wt% An aluminum alloy containing one or more of the following Sn and the balance aluminum and unavoidable impurities, and the core material is more than 0.6 wt% and 1.2 wt% or less of Si, 0.05 wt%
%, 2.0% by weight or less of Mn, and 0.05% by weight
Over 0.5 wt% and less than Cu, 0.03 wt% over 0.5 wt% and less Mg, 0.03 wt% over 0.3 wt% and less Cr, 0.03 wt
% Over 0.3 wt% Zr, 0.03 wt% over 0.3 wt%
The following sacrificial material is used as an aluminum alloy containing one or more of the following Ti and more than 0.03 wt% and less than 1.5 wt% Ni, and the balance aluminum and unavoidable impurities.
Zn over 0.5 wt% and under 6.0 wt%, over 0.002 wt%
Contains 0.3 wt% or less of In, 0.002 wt% or more and 0.3 wt% or less of Sn, and contains 0.05 wt.
%, Mg less than 2.5 wt% and less than 0.05 wt%, 1.6 wt%
An aluminum alloy brazing sheet comprising one or two of the following Mn, and an aluminum alloy comprising the balance aluminum and inevitable impurities. 5. A brazing heating temperature is 570 ° C. when a heat exchanger is manufactured by a brazing method using the brazing sheet according to any one of claims 1 to 4.
And a temperature of 585 ° C or less, a method for manufacturing an aluminum alloy heat exchanger.