JP2000343275A - Brazing filler metal, and flux for brazing aluminum or aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brazing tiller metal capable of achieving the brazing by feeding the brazing filler metal excellent in brazeability at <=570 deg.C, simple and necessary minimum in quantity, and a flux for brazing aluminum or aluminum alloy. SOLUTION: The brazing filler metal consists of a non-corrosive flux containing KAlF4 and K3AlF6, and at least one kind selected from a group consisting of K2CO3, SrF2 and MgF2, and a powder brazing filler metal containing, by weight, 5-13% Si, >=2% Cu, 1-5% Zn and 0.5-5% N, and the balance Al with inevitable impurities, and the total content of Cu and Zn is >=5%. The flux contains KF, AlF3 and K2CO3, or contains KF, AlF3 and MgF2, or KF, AlF3 and SrF2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing material and a brazing flux effective for low-temperature brazing of aluminum or an aluminum alloy material at a temperature of 570.degree. The simple and necessary minimum amount of brazing is required for parts where the brazing sheet is difficult to apply in a complicated shape such as a joint with a slow rise in temperature or a joint between a header and a pipe in a member that is large and has a different heating rate depending on the brazing part. The present invention relates to a brazing material and a brazing flux capable of supplying a material.

[0002]

2. Description of the Related Art Conventionally, a brazing sheet is generally used for brazing a heat exchanger made of aluminum alloy for automobiles. Further, in brazing at a joint where the shape of the header and the pipes or the like is complicated, for example, a ring-shaped brazing filler metal or a paste-like powder brazing filler metal is used.

[0003] Brazing materials and their brazing methods include:
Usually, for example, in the case of Al-Si based brazing materials such as JIS A4343 and A4045, these brazing materials are heated to about 600 ° C.

Further, as a low-temperature brazing aluminum alloy brazing material for brazing at a temperature lower than 600 ° C.,
For example, there is an Al-Si-Cu-Zn brazing material, and the brazing material is heated to 580 [deg.] C. to perform brazing (Japanese Patent Laid-Open No. 8-104936).

Further, when a Zn-Al-based brazing material is used, it is heated to about 450 ° C. and brazed (JP-A-6-79495, etc.).

[0006] Furthermore, a method of using an Al-Si- (Zn) -based core material and a Cu-Ni-based clad material as a foil has been proposed (Development of a fluxes, low temperat).
urealuminum brazing process: Flexless low temperature aluminum brazing method; ALUMINUM Vol. 71, No. 19
February 1995, pp. 215-219).

On the other hand, as a brazing powder and a brazing method using a brazing powder, a method using an aluminum brazing powder and a paste containing Nocolok (trade name) flux and liquid polyisobutylene and / or a hydrogenated product thereof is used. (JP-A-4-333390).

Further, an aluminum brazing material containing an aluminum powder, a metal powder lower than aluminum and a flux material has been disclosed (Japanese Patent Application Laid-Open No. 6-179094).

Further, there is disclosed an aluminum brazing paste for torch brazing or in-furnace brazing of an aluminum member containing an aluminum alloy powder, a flux, an organic polymer binder and an organic solvent (JP-A-6-3157).
No. 89 and JP-A-7-155987).

[0010] Furthermore, an aluminum alloy, a substance higher than the melting point of the aluminum alloy, and an aluminum brazing material containing a flux have been disclosed (Japanese Unexamined Patent Publication No. Hei 7-1995).
No. 284982).

[0011] A mixed powder compact containing Al, Si and a flux component as a brazing material component (processed into a flat plate or a wire)
Which specifies the content of the brazing filler metal Si, the weight ratio between the brazing filler metal and the flux, and the density thereof (Japanese Patent Laid-Open No. 6-304).
778) and a method of brazing an aluminum material containing Mg by using a chloride-based flux (JP-A-6-91393).

Furthermore, there has been proposed a technique of brazing an Mg-containing aluminum alloy by using a fluoride-containing non-corrosive flux, containing a potential lowering component in the brazing filler metal (JP-A-9-1384). .

Furthermore, there has been proposed a method in which an Al-Si alloy brazing powder is applied as a binder to a joint of a core portion of an automobile radiator, capacitor, evaporator, or the like, and is heated and brazed (JP-A-3-114654). No.).

A method of brazing aluminum to a metal surface using an alloy braze having a melting point lower than the melting point of the surface to be joined has been proposed.
504485). In this method, a coating mixture composed of a metal powder of Si, Cu, and Ge and a fluoride-based flux or the like is applied to the bonding surface, and the aluminum materials are brazed at a temperature of 500 to 650 ° C.

Further, in the ternary phase diagram of brazing material made of Al, Si, Cu and Zn, and KF, LiF and CsF, 5
A flux-containing Al alloy brazing material comprising a flux having a liquidus temperature of 50 ° C. or lower has been proposed (Japanese Patent Application Laid-Open No. 7-1177).

Further, a method has been proposed in which a metal powder having a melting point of 340 to 550 ° C., a binder and a flux are interposed in a joint portion and brazing is performed (JP-A-3-358).
No. 94).

In the brazing of an aluminum alloy material, an oxide film formed on the surface of the aluminum alloy material impairs the wetting and fluidity of the brazing material. There is a need to remove the coating.

Conventionally, for brazing aluminum or aluminum alloy materials, Japanese Patent Publication No. 62-46280 proposes a flux composition comprising a mixture of KAlF ₃ and K ₃ AlF ₆ . However, such a flux melts at the eutectic point of KF-AlF ₃ and acts as a flux, but its melting onset temperature is 560 ° C. For this reason, the brazing temperature is necessarily 560 ° C. or higher.

On the other hand, Japanese Patent Application Publication No. 1-48120 discloses that a compound having a melting point of 560 ° C. or more can act as a flux when the molar ratio of aluminum fluoride to cesium fluoride is 67/33 or less. A flux comprising a cesium fluoroaluminate having a composition corresponding to 26/74 or a mixed composition of cesium fluoroaluminate and aluminum fluoride is disclosed.

[0020]

However, in the brazing method using a generally used Al-Si brazing material, since the brazing material is heated to about 600 ° C., the power cost for heating is reduced. And the life of the furnace and the jig are shortened, so that the production cost of the heat exchanger is increased. Further, there is a problem that the application target is limited to the joining of the high melting point material due to the restriction from the melting point of the brazing material.

In the case of the Al-Si-Cu-Zn-based alloy disclosed in Japanese Patent Application Laid-Open No. 8-104936,
By adjusting the contents of i, Cu and Zn, brazing at 570 ° C. or less is possible, but in a high Cu and high Zn composition having a low melting point, the wettability of the brazing is insufficient,
There is a problem that sufficient brazing performance cannot be obtained.

Further, when a conventional Zn-Al-based brazing material disclosed in Japanese Patent Application Laid-Open No. 6-79495 is used,
Since chloride-based corrosive flux is used, cleaning after brazing is required, and there is a problem that waste liquid treatment is required due to environmental and pollution problems. Furthermore, this Zn-A
When an l-type brazing material is used as a sheet material, there is a problem in rollability for forming the sheet material.

Further, according to the method described in ALUMINUM Vol. 71, Feb. 1995, pp. 215 to 219, a Cu—N—N—Al—Si—Zn alloy is used as a brazing material.
Since the clad foil in which the i-based alloy is laminated is used, there are problems that the production cost is extremely high and mass production is difficult.

On the other hand, the method using the above-mentioned conventional powder brazing material (Japanese Patent Application Laid-Open Nos. 6-179094 and 6-31)
In JP-A-5789, JP-A-7-155987, JP-A-7-284982, JP-A-6-304778 and JP-A-9-1384, brazing is performed at a low temperature of 570 ° C. or lower. There is a problem that can not be.

Further, those using a conventional binder (JP-A-4-333390, JP-A-3-114654)
Japanese Patent Application Laid-Open No. 3-35894 and Japanese Patent Application Laid-Open No. 3-35894 have a problem that the cost is increased because a binder is used.

Further, the brazing material disclosed in Japanese Patent Application Laid-Open No. Hei 6-91393 is for brazing an aluminum material containing Mg, and thus has a problem that the applicable range is narrow.

Furthermore, the brazing material disclosed in Japanese Patent Publication No. 6-504485 is a powder mixture of Nocolok (trade name) flux, an aluminum alloy, and one metal powder such as Si which forms a eutectic alloy. Is applied and brazed by Nocoloc at about 600 ° C. In the heating process, the aluminum alloy material to be joined and the Si particles in the flux react to form an Al-Si alloy, which acts as a brazing material. It is then brazed. For this reason, the brazing mechanism is different. The brazing temperature is 570 ° C
There is a problem that it is above.

The brazing material disclosed in Japanese Patent Application Laid-Open No. 7-1177 has a problem that the cost increases because CsF is used.

In the flux disclosed in Japanese Patent Publication No. 1-48120, cesium fluoroaluminate cannot be used in large quantities because potassium fluoraluminate is not available in large quantities and is expensive. There is a problem. Further, there is a problem that brazing cannot be performed at a temperature of 560 ° C. or less.

The present invention has been made in view of the above problems, and has excellent brazing properties at a temperature of 570 ° C. or less, and can be brazed and joined by supplying a necessary and minimum amount of brazing material. It is an object of the present invention to provide a brazing material and a flux for brazing aluminum or an aluminum alloy material.

[0031]

The brazing material according to the present invention contains KAlF ₄ and K ₃ AlF ₆ and at least one selected from the group consisting of K ₂ CO ₃ , SrF ₂ and MgF _2. A non-corrosive flux containing 5 to 13% by weight of Si, 2% or more by weight of Cu, 1 to 5% by weight of Zn and 0.5 to 5% by weight of Ni, with the balance being Al and inevitable impurities. And the total content of the Cu and Zn is 5% by weight or more.

In this case, the non-corrosive flux is K
The AlF ₄ —K ₃ AlF ₆ —SrF ₂ system or the non-corrosive flux is preferably composed of a KAlF ₄ —K ₃ AlF ₆ —MgF ₂ system. The content of the brazing powder is [A], and the content of the non-corrosive flux is [B].
Where the ratio [A] / [B] of the above [A] and [B]
Is preferably from 95/5 to 60/40. Further, the average particle diameter of the powder brazing material is preferably 300 μm or less. Still further, a mixture of the non-corrosive flux and the powdered brazing material is supplied to a joint between members to be brazed.

The flux for brazing the first aluminum or aluminum alloy material according to the present invention is KF, AlF
₃ and K ₂ CO ₃ , and the KF content is 23.9.
54.5 mass%, the content of the AlF ₃ is 20.5
To 53.1% by mass, and the content of K ₂ CO ₃ is 0.5 to 25.0% by mass.

The flux for brazing the second aluminum or aluminum alloy material according to the present invention is KF, AlF
₃ and MgF ₂ , the KF content is 23.9 to 54.5% by mass, the AlF ₃ content is 25.5 to 53.1% by mass, and the MgF ₂ content is 0. 5 to 25.0% by mass.

The flux for brazing the third aluminum or aluminum alloy material according to the present invention is KF, AlF
₃ and SrF ₂ , the KF content is 28.5 to 54.5% by mass, the AlF ₃ content is 25.5 to 53.1% by mass, and the SrF ₂ content is 0. 5 to 20.0% by mass.

In this case, the KF and the AlF_ThreeIs
Some or all K_ThreeAlF₆Or KAlF_FourAdded as
Can be done. The flux is, for example, powder
It is mixed in powder form. In addition, K in water or alcohol_Two
CO_ThreeAnd KF, AlF _Three, K_ThreeAlF₆And KAl
F_FourOne or more selected from the group consisting of the water or
Disperse in alcohol and apply to the joint surface of the brazing material
You can do so. As for the type of alcohol,
Although not particularly limited, ethyl alcohol,
Use tyl alcohol and isopropyl alcohol
Can be

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a brazing material according to an embodiment of the present invention and a flux for brazing aluminum or an aluminum alloy material will be described in detail. The inventors of the present application have conducted intensive studies and found that the flux was KAlF ₄ −
Based on the K ₃ AlF ₆ system, the KAlF ₄ and K ₃ A
By adding a non-corrosive flux composed of a compound obtained by appropriately adding at least one selected from the group consisting of K ₂ CO ₃ , SrF ₂ and MgF ₂ to IF ₆ ,
It has been found that at a brazing temperature of 570 ° C. or less, it has an effect of effectively destroying the oxide film on the joint surface. For this reason, brazing at a low temperature of 570 ° C. or less is possible,
The wettability with the aluminum joining member is also good.

Further, by specifying the brazing material composition and the flux composition, the mixing ratio between the brazing material composition and the flux composition, and the average particle size of the brazing material, the brazing property is excellent at 570 ° C. or less, and it is simple and necessary. It has been found that brazing can be performed by supplying an amount of brazing material. Further, since a non-corrosive flux is used, post-cleaning for preventing corrosion is not required.

Further, as a flux that melts at a temperature of 560 ° C. or less, a flux composed of a mixture of KF, AlF ₃ and K ₂ CO ₃ at a predetermined ratio was found, and by using this flux, a temperature of 560 ° C. We have found that brazing is possible below. In addition to this composition, 5
KF, AlF ₃ , MgF ₂ and K ₂ CO ₃
And a mixture formed by mixing one selected from the group consisting of at a predetermined ratio. It has been found that brazing can be performed at 560 ° C. or less even using this flux.

The reasons for limiting the composition of the brazing material of the present invention and the flux for brazing aluminum or aluminum alloy material will be described below.

Non-corrosive flux As the non-corrosive flux, KAlF ₄ -K ₃ AlF ₆
Based on the system, the KAlF ₄ and K ₃ AlF ₆
Furthermore, the oxide film on the joint surface can be formed at a brazing temperature of 570 ° C. or less by using a compound composed of a compound to which at least one selected from the group consisting of K ₂ CO ₃ , SrF ₂ and MgF ₂ is appropriately added. It has the effect of effectively destroying. Therefore, brazing at a low temperature of 570 ° C. or less is possible. Also, since it is a non-corrosive flux, post-cleaning when chloride is used is not necessary, and it can be used easily. K ₂ CO ₃ is less expensive than CsF or the like.

Si: 5 to 13% by weight Si has an effect of lowering the melting point of the flux-containing aluminum alloy brazing material. When the content of Si is less than 5% by weight, the effect of lowering the melting point is insufficient. On the other hand, S
When the content of i exceeds 13% by weight, the melting point of the flux-containing aluminum alloy brazing material exceeds 570 ° C.
Brazing at 570 ° C. or less cannot be performed. Therefore, S
The content of i is preferably 5 to 13% by weight.
Note that a more preferable Si content is 7 to 12% by weight.

Cu: 2% by weight or more Cu has a function of lowering the melting point of the flux-containing aluminum alloy brazing material. If the Cu content is less than 2% by weight, the melting point of the flux-containing aluminum alloy brazing material is 5%.
Since the temperature exceeds 70 ° C., brazing at 570 ° C. or less cannot be performed. Therefore, the content of Cu is preferably set to 2% by weight or more. The upper limit of the Cu content is not particularly limited, but if the Cu content is large, the potential of the brazing material portion after brazing becomes more noble than the potential of the tube material or the like to be protected from corrosion, which is inconvenient. If the Cu content is 6% by weight or less, there is no practical problem.

Zn: 1 to 5% by weight or more Zn has a function of lowering the melting point of the flux-containing aluminum alloy brazing material. If the Zn content is less than 1% by weight, the melting point of the flux-containing aluminum alloy brazing material is 5%.
Since the temperature exceeds 70 ° C., brazing at 570 ° C. or less cannot be performed. On the other hand, when the content of Zn exceeds 5% by weight,
It preferentially corrodes the braze fillet and degrades the corrosion resistance of the braze joint. Therefore, the content of Zn is 1
It is preferable that the content be 5 to 5% by weight.

The total content of Cu and Zn: 5% by weight or less
If the total content of upper Cu and Zn is less than 5% by weight, the melting point of the flux-containing aluminum alloy brazing material exceeds 570 ° C, so that brazing at 570 ° C or less cannot be performed. The Cu content exceeds 6% by weight or Z
If the content of n exceeds 5% by weight, the effect of lowering the melting point of the flux-containing aluminum alloy brazing material is saturated, so that further addition of Cu and Zn only increases the cost. Therefore, the total content of Cu and Zn is preferably set to 5% by weight or more.

Ni: 0.5 to 5% by weight Ni has an effect of improving wettability with a joining member made of an aluminum alloy during brazing. For this reason, Ni is an essential additive element for forming a good fillet. When the content of Ni is less than 0.5% by weight, the effect of improving the wettability is insufficient. On the other hand, N
When the content of i exceeds 5% by weight, the wettability decreases.
Therefore, the content of Ni is preferably set to 0.5 to 5% by weight. A more preferred Ni content is 1 to 3% by weight.

The addition of a small amount of an alkali metal or an alkaline earth metal to the powder brazing material further improves the brazing performance due to the effect of refinement of eutectic Si in the Al—Si alloy. The addition of a trace amount into the brazing material is not restricted.

The content of the brazing powder [A] and the non-corrosive
Ratio [A] / [B] to the content [B] of the resin: 95/5
When the content [B] of the non-corrosive flux of from 60/40 to less than 5% by weight, the effect of destroying the oxide film at the joint is insufficient.
For this reason, the brazing property deteriorates. On the other hand, when the content [B] of the non-corrosive flux exceeds 40% by weight, brazing itself is possible, but the appearance of the fillet portion becomes dirty due to the residue of the flux, which leads to poor appearance of the product. Therefore, the ratio [A] / [B] of the content [A] of the brazing powder and the content [B] of the non-corrosive flux is 95/5 to 60.
/ 40 is preferable.

Average particle size of powdered brazing material : 300 μm or less If the average particle size of powdered brazing material exceeds 300 μm, brazing is possible but the powdered brazing material is uniformly dispersed and suspended in the paste with the flux. It becomes difficult and workability deteriorates.
Therefore, it is preferable that the average particle diameter of the powder brazing material is 300 μm or less. The more preferable average particle size of the powder brazing material is 100 μm or less.

Filter for aluminum or aluminum alloy material
Flux for brazing The flux for brazing aluminum or aluminum alloy material according to the present invention has the following composition.

When KF, AlF ₃ and K ₂ CO ₃ are contained, KF: 23.9 to 54.5% by mass, AlF ₃ :
20.5 to 53.1% by mass, K ₂ CO ₃ : 0.5 to 2
When containing 5.0% by mass, KF, AlF ₃ and MgF ₂ , KF: 2
3.9 to 54.5% by mass, AlF ₃ : 25.5 to 5
3.1% by mass, MgF ₂ : 0.5 to 25.0% by mass When KF, AlF ₃ and SrF ₂ are contained, KF: 2
8.5 to 54.5% by mass, AlF ₃ : 25.5 to 5
3.1 wt%, SrF _2: 0.5 to 20.0 wt%.

Aluminum or aluminum according to the present invention
Flux for brazing alloys is KF and AlF_Three
And then K_TwoCO_Three, MgF_TwoAnd SrF_TwoAt least one of
Contains seeds. KF and AlF_ThreeMixed state
For the flux of_TwoCO _Three, MgF_TwoOr SrF_TwoTo
When added, the melting point of the flux decreases, and
Brazing temperature below 560 ° C, which could not be brazed with
Brazing becomes possible.

In this case, if the content of K ₂ CO ₃ is 0.5% by mass or more, the effect of lowering the melting point of the flux can be obtained. However, if the content of K ₂ CO ₃ in the flux exceeds 25.0% by mass and the concentration is too high, the melting point will increase and the concentration of fluoride will decrease, conversely. Fluorine required for brazing is reduced, and is not suitable for brazing aluminum and aluminum alloy materials. Therefore, the content of K ₂ CO ₃ is set to 0.5 to 25.0% by mass.

When K ₂ CO ₃ is used, the proportions of the other components, KF and AlF ₃ , are 23.9% by mass or more, respectively.
0.5 mass% or more is necessary, and the content of KF is 23.9.
When the content is less than 2% by mass and the content of AlF ₃ is less than 20.5% by mass, the melting point of the flux becomes high, which is not suitable for low-temperature brazing. On the other hand, if the KF content exceeds 54.5% by mass and the AlF ₃ content exceeds 53.1% by mass, the melting point of the flux also becomes high, which is not suitable for low-temperature brazing.

Therefore, the content of KF is 23.9 to 5
4.5 mass%, and the content of AlF ₃ is 20.5 to 5
3.1 mass%, and the content of K ₂ CO ₃ is 0.5 to 2
5.0 mass%. More preferably, KF is 33.1
To 54.0% by mass, and AlF ₃ is 36.0 to 5%.
3.1% by mass and K ₂ CO ₃ is 1.0 to 15.0% by mass.

Also, MgF ₂ and SrF ₂ have the same effect as K ₂ CO ₃ . That is, MgF ₂ and SrF ₂ are also K ₂ C
As with O ₃ , the flux of the mixed state of KF and AlF ₃ lowers the melting point of the flux, enabling brazing at a brazing temperature of 560 ° C. or less, which could not be brazed with a conventional flux. .

When the content of MgF ₂ or SrF ₂ is 0.5
If it is at least% by mass, an effect of lowering the melting point of the flux can be obtained. However, also in this case, the content of MgF _{2 in} the flux exceeds 25.0% by mass, or Sr
If the content of F ₂ exceeds 20.0% by mass and the concentration is too high, the melting point will increase, and the concentration of fluoride will decrease. And becomes unsuitable for brazing aluminum and aluminum alloy materials. Therefore, the content of MgF ₂ is 0.1.
5 to 25.0% by mass, the content of SrF ₂ is 0.5 to 2
0.0 mass%.

When MgF ₂ is used, the proportions of the other components, KF and AlF ₃ , are 23.9% by mass or more, respectively.
5.5 mass% or more is necessary, and the content of KF is 23.9.
If the content is less than 2% by mass and the content of AlF ₃ is less than 25.5% by mass, the melting point of the flux becomes high, which is not suitable for low-temperature brazing. Further, the content of KF exceeds 54.5% by mass,
When the content of F ₃ exceeds 53.1% by mass, the melting point of the flux also becomes high, which is not suitable for low-temperature brazing.

Therefore, the content of KF is 23.9 to 5
4.5 mass%, and the content of AlF ₃ is 25.5 to 5
3.1 mass%, and the content of MgF ₂ is 0.5 to 2
5.0 mass%. More preferably, KF is 33.1
To 53.8% by mass, and AlF ₃ is 41.2 to 5%.
3.1% by mass, and MgF ₂ is 0.8 to 15.0% by mass.

When SrF ₂ is used, the proportions of the other components, KF and AlF ₃ , need to be 28.5% by mass or more and 25.5% by mass or more, respectively.
If the content is less than 8.5% by mass and the content of AlF ₃ is less than 25.5% by mass, the melting point of the flux becomes high, which is not suitable for low-temperature brazing. Further, the content of KF exceeds 54.5% by mass,
If the content of AlF ₃ exceeds 53.1% by mass, the melting point of the flux also becomes high, which is not suitable for low-temperature brazing. Therefore, the content of KF is 28.5 to 5
4.5 mass%, and the content of AlF ₃ is 25.5 to 5
3.1 mass%, and the content of SrF ₂ is 0.5 to 2
0.0 mass%. More preferably, KF is 33.1
To 54.0% by mass, and AlF ₃ is 36.0 to 5%.
3.1% by mass, and SrF ₂ is 1.0 to 15.0% by mass.

The flux for brazing aluminum or aluminum alloy material according to the present invention uses a mixture of powders of the respective components within the above-mentioned range as a flux. The flux of the present invention can be brazed at a brazing temperature of 560 ° C. or less by suspending the flux in a liquid such as water or alcohol and then heating.

K ₂ CO ₃ has some solubility in water. Therefore, in the present invention, before brazing,
If water is used to apply the flux to the joint surface of the brazing material, K ₂ CO ₃ is dissolved in an aqueous solution in advance, and a substance defined in the present invention other than K ₂ CO ₃ is used. After being dispersed and applied in this solution and dried, the composition may be brazed so as to have the composition specified in the claims of the present invention. Even when such a coating method is used, the flux before brazing is the same as the case where K ₂ CO ₃ is mixed with other fluorides and suspended in an aqueous solution, and the effect on brazing is not recognized. .

Further, the flux according to the present invention comprises K ₃ AlF ₆ or KAl which is a composite fluoride of KF and AlF _3.
The F ₄ even when used as a raw material of a flux, there is no change in the brazing.

[0064]

EXAMPLES Examples of the brazing material and the flux for brazing aluminum or aluminum alloy material within the scope of the present invention will be specifically described below by comparing the brazing property of an aluminum alloy plate with a comparative example. . FIG. 1 is a schematic view showing a brazed joint.

First Example An aluminum alloy having the composition shown in Table 1 below was melted and manufactured by an atomizing method in a non-oxidizing atmosphere. In addition, it can also be manufactured by a pulverizing method using a ball mill or the like.

Next, the powder was classified into various particle sizes and used as a powder brazing material. And the flux shown in the following Table 2 was mixed, and it tested after grinding | pulverizing with a ball mill. In order to mix the powdered brazing material and the flux, ion-exchanged water is used as a dispersion liquid to form a paste, and the concentration is set to 20%. The mixing ratio of the powdered brazing material and the flux is the weight ratio shown in Table 3 below. A brazing material was produced. Note that ethyl alcohol can be used instead of ion-exchanged water.

Next, JIS H4000 was used as a test piece.
A3003 material having a plate thickness of 1 mm, a width of 20 mm, and a length of 60 mm as specified in the above was used. As shown in FIG. 1, using two test pieces 1, one is made horizontal in the width direction, and the other one is made vertical to the width direction on the test piece 1 in which the horizontal direction is formed. The brazing material 2 was applied to the joints of the test pieces 1 in an amount of 1 to 2 g per sheet. Then, a brazing heating test was performed by heating at 570 ° C. for 5 minutes in a nitrogen gas atmosphere. Thereafter, the appearance of the test piece 1 and the state of fillet formation in the cross section were evaluated.

The fillet shape is JIS Z3263 (1
980), and brazing at 605 ° C. using Nocolok® flux as the non-corrosive flux.

Further, the corrosion resistance was evaluated by the CASS test to evaluate the preferential corrosion of the fillet.

The evaluation of the state of fillet formation was evaluated as A when it was almost the same as the standard, B when it was slightly inferior, and C when brazing was possible but the fillet formation was unstable.

Regarding the evaluation of the appearance of the brazing, A having a clean surface with a small amount of flux residue was designated as A, and one having a slight flux residue or discoloration was designated as B. Those having a rough surface or having a black surface and a dirty surface were designated C.

The preferential corrosion of the fillet portion was evaluated as ○ when no preferential corrosiveness of the fillet portion was observed, and Δ when the fillet portion had a slight tendency to corrode but did not penetrate. Was evaluated as x, which resulted in penetration corrosion. Table 4 shows the results.

In Table 4, "-" indicates that the evaluation could not be performed.

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

[Table 3]

[0077]

[Table 4]

As shown in Table 4, Examples Nos. 1 to 12 falling within the scope of the present invention were excellent in brazing properties at 570 ° C. or lower and corrosion resistance of the fillet portion. On the other hand, in Comparative Examples 13 to 19, good results could not be obtained with respect to the brazing property and the corrosion resistance of the fillet portion.

Comparative Example No. 13 could not be brazed at 570 ° C. because the content of Si was less than the range of the present invention.

Comparative Example No. 14 could not be brazed at 570 ° C. because the content of Si exceeded the range of the present invention.

In Comparative Example No. 15, since the Ni content was less than the range of the present invention, the wettability of the joint between the test pieces was reduced, and the fillets were formed but unstable.

In Comparative Example No. 16, since the Ni content exceeded the range of the present invention, the wettability of the joint between the test pieces was reduced and a fillet was formed, but was unstable.

Comparative Example No. 17 did not contain any flux, so that the oxide film formed on the surface of the joint between the test pieces could not be destroyed and could not be brazed at 570 ° C. Was.

Comparative Example No. 18 had good brazing performance because the flux content exceeded the range of the present invention, but the flux residue left the surface clean and was unsuitable as a brazing product. It was judged.

In Comparative Example No. 19, since the Zn content was beyond the range of the present invention, the fillet portion penetrated due to preferential corrosion.

Comparative Example No. 20 could not be brazed at 570 ° C. because the Cu content was less than the range of the present invention.

Comparative Example No. 21 could not be brazed at 570 ° C. because the total content of Cu and Zn was less than the range of the present invention.

Comparative Example No. 22 could not be brazed at 570 ° C. because the Zn content was less than the range of the present invention.

Comparative Example No. 23 could not be brazed at 570 ° C. because the composition of the flux was out of the range of the present invention.

[0090]Second embodiment A flux having a composition falling within the scope of the present invention (Example N
o.1 to 3) were prepared. In addition, the comparative material (Comparative Example No.
1) is described in JP-B-60-46280.
Of the flux composition that melts at the lowest temperature
A flux having the following characteristics was used. Example No. 1
The composition of the mixture was 45.2% by mass KF-53.0% by mass A.
IF_Three-1.8 mass% K_TwoCO_ThreeAnd the set of Example No. 2
The composition is 46.1 mass% KF-53.1 mass% AlF_Three−
0.8 mass% MgF_TwoAnd the composition of Example No. 3 was 4
4.7 mass% KF-52.8 mass% AlF_Three-2.5 quality
% SrF _TwoIt is. Also, the flux of Comparative Example No. 1
The composition is 46.8% by mass KF-53.2% by mass AlF_Three
It is.

FIG. 2 is a perspective view showing the shape and arrangement of test materials in the gap filling brazing test. A gap filling brazing test was performed on the examples and comparative examples to evaluate the brazing property. As shown in FIG. 2, in the gap filling brazing test, a columnar spacer 5 is placed on a second test material 4 having a horizontal plate width direction and in a height direction and a plate width direction of the test material 4. Are arranged in parallel. The first test material 3 is placed on the test material 4 such that the width direction of the first test material 3 is perpendicular to the upper surface of the test material 4 and the spacer 5 is at a predetermined position. Note that the first test material 3 is fixed to the second test material 4 with the wire 10 so that the first test material 3 does not fall.

In this brazing test, a brazing sheet was used as the test material 3. A material equivalent to JIS 3003 is used as a core material and a base material of the brazing sheet, and Al-7.5 mass% Si-4.0 mass% Cu-4 is used so that the brazing material starts melting at a temperature of 550 ° C. or less. .
An aluminum alloy having a composition of 0 mass% Zn-2.0 mass% Ni was used. The plate thickness of the brazing sheet is 2.0 mm, and the brazing material is clad on both sides of the core at a rate of 5% with respect to the plate thickness of the brazing sheet.

Further, the first test material 3 has a plate width of 25 mm,
The length of the plate is 55 mm, and the second test material 4 is JIS3
003 equivalent material, plate width 25mm, plate length 6
0 mm. The spacer 5 is made of SUS304 and has a diameter of 4 mm.

The flux used was suspended at a mass ratio of 10% by mass with respect to water, and was sprayed so as to be about 5 g / m ^{2 over the} entire surface of the test materials 3 and 4 by spraying. Coated and dried.

Thereafter, the brazing test is performed by heating and brazing in an infrared heating furnace in a nitrogen atmosphere having an oxygen concentration of 200 mass ppm or less and a dew point of -40 ° C. or less. The heating temperature was 510 to 590 ° C., and the heating holding time at the target temperature in the temperature range was 2 minutes. Figure 3 is a schematic view showing a filling length F _L of the brazing material after brazing. After brazing was measured in the first test material 3 filling length F _L of the wood at the junction 6 formed between the second test material 4.
In the brazing test, if the filling length _FL is 30 mm or more, it is sufficient for practical use. FIG. 4 is a graph showing the brazing property of the flux by taking the brazing holding temperature on the horizontal axis and the filling length on the vertical axis, and FIG. 5 shows the brazing holding temperature on the horizontal axis and the filling length on the vertical axis. FIG. 3 is a graph showing the brazing property of a flux. In FIG. 4, ○ indicates Example No. 1 and ● indicates Comparative Example No. 1. In FIG. 5, ○ indicates the example No.
2, No. 3 and No. 2 indicate Comparative Example No. 1, respectively. The results are shown in FIGS.

As shown in FIGS. 4 and 5, in Examples Nos. 1 to 3, even when the brazing holding temperature was lower than 560 ° C., the filling length exceeded 30 mm, which was sufficient for practical use. Was something. On the other hand, in Comparative Example No. 1, the brazing temperature had to be 560 ° C. or higher to be practical.

Third Example Using a flux having the composition shown in Tables 5 to 8 below, a brazing-filling brazing test was performed under the same conditions as in the second example except that the temperature of the soldering heat was set to 550 ° C. The filling length was measured. In the evaluation of the brazing test, those having a filling length of 30 mm or more were rated as ○, those with a filling length of 10 mm or more and less than 30 mm were rated as Δ, and those with a filling length of less than 10 mm were rated x. Tables 5 and 6 show the results of the flux composed of KF, AlF ₃ and K ₂ CO ₃ . Also, KF, AlF ₃ and M
Table 7 shows the results of the flux composed of gF ₂ . Furthermore,
Table 8 shows the results of the flux composed of KF, AlF ₃ and SrF ₂ .

[0098]

[Table 5]

[0099]

[Table 6]

As shown in Tables 5 and 6, Example No.
Nos. 1 to 20 had a long filling length and were sufficiently practical. In particular, Examples Nos. 3 to 8 and 13 and 17
Since the composition of the flux was within the preferred range, the filling length was long and the evaluation was good.

On the other hand, since Comparative Example No. 57 did not contain K ₂ CO ₃ , the filling length was short and the evaluation was poor, so that it was not practically usable. Comparative Examples No. 58, 59 and 6
In No. _{3, since} the content of K ₂ CO ₃ is less than the lower limit of the present invention, the filling length is short and the evaluation is poor. Comparative Examples No. 60 and 6
In No. 1, since the contents of KF and K ₂ CO ₃ are less than the lower limit of the present invention, the filling length is short and the evaluation is poor. Comparative Example No. 62
Means that the content of AlF ₃ exceeds the upper limit of the present invention and K ₂ CO ₃
Is less than the lower limit of the present invention, the filling length is short and the evaluation is poor. In Comparative Examples Nos. 64 and 65, since the contents of AlF ₃ and K ₂ CO ₃ are less than the lower limit of the present invention, the filling length is short and the evaluation is poor.

[0102]

[Table 7]

As shown in Table 7, in Examples Nos. 21 to 39, even when the brazing temperature was 550 ° C., the filling length was long, and the evaluation was sufficient for practical use. In particular, since Examples Nos. 22 to 28 and 32 to 36 were within the preferred ranges, the filling length was even longer and the evaluation was good.

At a step, since Comparative Example No. 66 did not contain MgF ₂ , the filling length was shortened at a brazing temperature of 550 ° C., and the evaluation was poor, and it was not possible to sufficiently endure practical use. In Comparative Examples Nos. 67 and 69, the content of AlF ₃ exceeds the upper limit of the present invention, and the content of MgF ₂ is lower than the lower limit of the present invention. In Comparative Example No. 68, the content of KF was less than the lower limit of the present invention, and the content of MgF ₂ exceeded the upper limit of the present invention. In Comparative Example No. 70, since the content of AlF ₃ was less than the lower limit of the present invention, the filling length was short, and the evaluation was poor.

[0105]

[Table 8]

As shown in Table 8, in Examples Nos. 40 to 56, even at a brazing temperature of 550 ° C., the filling length was long and brazing sufficient for practical use could be performed. . In particular, in Examples Nos. 41 to 46 and 50 to 54, since the composition of the flux was within the preferable range, the evaluation in the brazing test was good even when the brazing temperature was 550 ° C.

On the other hand, in Comparative Example No. 71, the flux was Sr.
F_TwoIs not contained, the filling length is shortened and 5
At a brazing temperature of 50 ° C, sufficient brazing can be performed.
Did not. Comparative Examples No. 72 and 75 are AlF_ThreeContent of
Exceeding the upper limit of the present invention, SrF _TwoContent of the present invention
Since it is less than the limit value, the filling length is shortened, and its evaluation is
bad. Comparative Example No. 73 is SrF_TwoIs the lower limit of the present invention.
Since it is less than the value, the filling length is shortened and the evaluation is bad.
No. In Comparative Example No. 74, the KF content was lower than the lower limit of the present invention.
Full, SrF_TwoExceeds the upper limit of the present invention
, The filling length is shortened, and its evaluation is bad. Comparison
Example No. 76 is AlF_ThreeIs less than the lower limit of the present invention.
SrF_TwoContent exceeds the upper limit of the present invention.
, The filling length is shortened, and the evaluation is poor.

Fourth Embodiment Using the fluxes having the same contents of KF and AlF ₃ and different compositions of the raw materials of the flux, the respective compositions shown in Tables 9 and 10 below were used, and the gap filling was performed under the same test conditions as in the third embodiment. A brazing test was performed to measure the filling length. In the flux of the present embodiment, KF and AlF ₃ were used as the fluoride of the raw material of the flux, and the total amount of the fluoride as the fluoride of the raw material of the flux was replaced with the composite fluoride instead of KF and AlF _3. Certain KF and AlF ₃ were used. The results are shown in Tables 9 and 10. In Tables 9 and 10, "-" indicates that the element was not added.

[0109]

[Table 9]

As shown in Table 9 above, even when a flux was produced by replacing the fluoride of Example No. 1 with a composite fluoride as in Example No. 2, the filling length exceeded 30 mm, It was enough to withstand practical use.

[0111]

[Table 10]

As shown in Table 10 above, even if the flux of Example Nos. 3 and 5 was replaced with a composite fluoride as in Examples Nos. 4 and 6, a filling length was obtained. It was more than 30 mm and could sufficiently withstand practical use.

Fifth Example A gap filling brazing test was performed under the same conditions as in the third example by using fluxes having the same composition as shown in Table 11 below, and changing the application form of the flux, and the filling length was measured. .

In Example No. 1, each component of the flux was mixed and then applied to the joint surface of the first test material. In Examples Nos. 2 and 3, K ₂ CO ₃ was previously dissolved in water and ethyl alcohol, and the solution was applied to the joint surface of the first test material and dried, and then KF, AlF ₃ and K K so that the content of ₂ CO ₃ is the same as in Example No. 1.
F and AlF ₃ are applied to the joint surface. This 3
Two examples were compared. Table 11 shows the results.

[0115]

[Table 11]

As shown in Table 11 above, in Examples Nos. 1 to 3, the filling length was long and the length exceeded 30 mm, regardless of the flux application form, and brazing that could sufficiently withstand practical use was carried out. We were able to.

[0117]

As described in detail above, in the present invention,
By specifying the composition of the brazing material and the composition of the non-corrosive flux, the brazing property is excellent at 570 ° C. or less, and the brazing can be performed by simply supplying the required minimum amount of brazing material. Further, since a non-corrosive flux is used, post-cleaning for preventing corrosion is not required. Therefore, a part where a brazing sheet is difficult to be applied in a complicated shape such as a joint having a low temperature rise or a joint between a header and a pipe in a large-sized member such as a heat exchanger material for an automobile and having a different heating rate depending on a brazing portion. Can be applied to

Further, by defining the mixing ratio between the brazing filler metal composition and the non-corrosive flux and the average particle size of the brazing filler metal,
The brazing property is further excellent at 570 ° C. or less, and brazing can be performed by supplying a simple and necessary minimum amount of brazing material.

In the flux of the present invention, since the composition of the flux is appropriately specified, when brazing aluminum or an aluminum alloy material, the brazing temperature is preferably set to 560 ° C. or lower and 530 ° C. or higher. it can.
For this reason, the limitation due to the melting point of the aluminum or aluminum alloy material used for the brazing material used for brazing and the core material is relaxed, and many aluminum or aluminum alloy materials can be used as the brazing core material.

Further, according to the brazing using the flux of the present invention, the brazing temperature can be reduced to 530 ° C. or less, and the time for raising the temperature during brazing can be shortened. Heating energy can be reduced, thereby reducing heating cost and installation cost of the heating equipment or repair cost for damage to the heating equipment.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a brazed joint.

FIG. 2 is a perspective view showing the shape and arrangement of test materials in a gap filling brazing test.

3 is a schematic view showing a filling length F _L of the brazing material after brazing.

FIG. 4 is a graph showing the brazing property of the flux, with the horizontal axis representing the brazing holding temperature and the vertical axis representing the filling length.

FIG. 5 is a graph showing the brazing property of the flux, with the horizontal axis representing the brazing holding temperature and the vertical axis representing the filling length.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Test piece 2; Brazing material 3, 4; Test material 5; Spacer 6; Joint 10; Wire

Claims (10)

[Claims] 1. KAlF_FourAnd K_ThreeAlF₆And K_TwoC
O_Three, SrF_TwoAnd MgF _TwoSelected from the group consisting of
A non-corrosive flux containing at least one
i: 5 to 13% by weight, Cu: 2% by weight or more, Zn: 1
To 5% by weight and Ni: 0.5 to 5% by weight.
And a brazing powder consisting of Al and unavoidable impurities.
And the total content of the Cu and Zn is 5% by weight.
A brazing material characterized by the above. 2. The content of the powder brazing material is [A],
When the content of the non-corrosive flux is [B],
The brazing material according to claim 1, wherein the ratio [A] / [B] of [A] and [B] is from 95/5 to 60/40. 3. An average particle size of the brazing powder is 300 μm.
The brazing material according to claim 1 or 2, wherein m is equal to or less than m. 4. The brazing method according to claim 1, wherein a mixture of said non-corrosive flux and said brazing powder is supplied to a joint between members and brazed.
Brazing material according to the item. 5. A flux used for brazing aluminum or aluminum alloy material, the flux comprising KF, Al
It contains F ₃ and K ₂ CO _3, and the content of KF is 23.
9 to 54.5% by mass, and the content of AlF ₃ is 20.
5 to 53.1% by mass, and the content of K ₂ CO ₃ is 0.5
A flux for brazing aluminum or an aluminum alloy material, wherein the flux is from 2 to 25.0% by mass. 6. A flux used for brazing aluminum or aluminum alloy material, the flux comprising KF, Al
Containing F ₃ and MgF _2, the content of the KF 23.9
-54.5 mass%, and the content of AlF ₃ is 25.5.
A flux for brazing aluminum or an aluminum alloy material, wherein the content of MgF ₂ is 0.5 to 25.0% by mass. 7. A flux used for brazing aluminum or aluminum alloy material, the flux comprising KF, Al
Containing F ₃ and SrF _2, the content of the KF 28.5
-54.5 mass%, and the content of AlF ₃ is 25.5.
A flux for brazing aluminum or an aluminum alloy material, wherein the content of SrF ₂ is 0.5 to 20.0 mass%. 8. The method according to claim 5, wherein the KF and the AlF ₃ are partially or entirely added as K ₃ AlF ₆ or KAlF _4. Flux for brazing aluminum alloy materials. 9. The flux for brazing aluminum or an aluminum alloy material according to claim 5, wherein the flux is mixed in a powder form. 10. A method for dissolving K ₂ CO ₃ in water or alcohol, dispersing at least one selected from the group consisting of KF, AlF ₃ , K ₃ AlF ₆ and KAlF _{4 in the} water or alcohol, The flux for brazing aluminum or an aluminum alloy material according to any one of claims 5 to 9, wherein the flux is applied to a joint surface of a brazing material.