JPH08164493A - Aluminum alloy brazing filler metal containing flux - Google Patents

Abstract

PURPOSE: To provide the aluminum alloy brazing filler metal containing the flux whose melting point is low, and which facilitates the uniform feeding of the flux, and excellent in the corrosion resistance and the brazeability. CONSTITUTION: The aluminum alloy brazing filler metal containing the flux contains the brazing filter metal composition and the flux composition, and the brazing filler metal and the flux are blended at the weight ratio of 99.9:01 to 70:30. The brazing filler metal has the composition consisting of, by weight, 30-60% Zn and 2-8% Si, and the addition element group (I) in order to improve the corrosion resistance and/or the additional element group (II) in order to improve the brazeability, and the balance Al with inevitable impurities, and the Fe content in the impurities is regulated to be <=0.01%. The addition element group (I) contains one or two or more kinds of 0.001-0.01% Be, 0.001-0.01% La, 0.001-0.01% Sr, 0.5-1.5% Mn, and 0.1-0.5% Cr, while the addition element group (II) contains 0.02-0.2% In, 0.05-0.4% Bi, and 0.05-0.4% Sn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux-containing aluminum alloy brazing material used for brazing a low melting point aluminum alloy material such as a casting material.

[0002]

2. Description of the Related Art In manufacturing a brazed product of a low melting point aluminum alloy material, a casting material such as AC4C alloy or AC2B alloy is used, and it is necessary to perform brazing at a temperature of 550 ° C. or lower due to restrictions on its melting point. is there. As a brazing material suitable for such a temperature condition, a brazing material having a melting point lower than that of a conventional Al-Si alloy brazing material is required.

Further, in the brazing of a low melting point aluminum alloy material, a flux is used to remove the oxide generated in the joint part and perform a good joint, as in the brazing of a normal aluminum material. As a method of supplying flux,
It is common to supply the flux suspension by coating and supply the gaseous flux into the brazing atmosphere. But,
With these supply methods, the brazing work is troublesome, it is difficult to make the amount of flux uniform, and an excessive amount of flux contaminates the brazed product and deteriorates the appearance quality and surface processability of the brazed product. There were problems such as.

Therefore, the present applicant has previously proposed a flux-containing brazing material for low-temperature brazing, which can be brazed at a lower temperature than the Al-Si alloy brazing material and can supply a fixed amount of flux to the joint at the same time. Developed (Japanese Patent Application No. 5-133317)
issue). This brazing material is a brazing alloy having a melting point lower than that of an Al-Si alloy, for example, an Al-Zn-Si alloy, and a brazing material component and a flux.

[0005]

However, the Al-Zn-Si alloy brazing material described above has the advantage that it can be brazed at a lower temperature than the Al-Si alloy brazing material.
It was not enough in terms of corrosion resistance. Therefore, the brazed product using the AC4C alloy casting material may be corroded from the brazed portion, and although the AC4C alloy cast product itself has good corrosion resistance, there is room for improvement in the corrosion resistance of the brazed product. In addition, when brazing a material having a low melting point among casting materials, the brazing temperature also becomes low. Therefore, an Al—Zn—Si alloy brazing material having a lower melting point than the Al—Si system may be used. In some cases, the flowability was not sufficient, and there was room for improvement in terms of brazing.

The present invention has been made in view of the above circumstances, and has a low melting point, easy uniform supply of flux, good corrosion resistance and brazing ability, or both of them. It is intended to provide a flux-containing aluminum alloy brazing material.

[0007]

The first flux-containing aluminum alloy brazing filler metal according to the present invention contains a brazing filler metal component and a flux component, and the brazing filler metal component and the flux component are weighted for the purpose of improving corrosion resistance. 99.
A flux-containing aluminum alloy brazing filler metal compounded in a ratio of 9: 0.1 to 70:30, wherein the brazing filler metal component contains Zn: 30 to 60 wt%, Si: 2 to 8 wt%, and Be. : 0.001-0.01 wt%, La:
0.001-0.01 wt%, Sr: 0.001-0.0
1 wt%, Mn: 0.5 to 1.5 wt%, Cr: 0.1
One or more of 0.5 wt% is contained, the balance is Al and unavoidable impurities, and the Fe content in the impurities is regulated to 0.01 wt% or less. .

The second flux-containing aluminum alloy brazing material contains a brazing material component and a flux component for the purpose of improving brazing property, and the brazing material component and the flux component are in a weight ratio of 99.9. : 0.1 to 70:
A flux-containing aluminum alloy brazing material blended at a ratio of 30, wherein the brazing material component is Zn: 30 to 6
0 wt%, Si: 2 to 8 wt%, and In: 0.
02-0.2 wt%, Bi: 0.05-0.4 wt%, S
n: One or more of 0.05 to 0.4 wt% is contained, the balance is Al and unavoidable impurities, and the Fe content in the impurities is regulated to 0.01 wt% or less. It is a feature.

Further, the third flux-containing aluminum alloy brazing material contains a brazing material component and a flux component, and the brazing material component and the flux component are in a weight ratio, for the purpose of improving corrosion resistance and brazing property. 99.
A flux-containing aluminum alloy brazing filler metal compounded in a ratio of 9: 0.1 to 70:30, wherein the brazing filler metal component contains Zn: 30 to 60 wt%, Si: 2 to 8 wt%, and Be. : 0.001-0.01 wt%, La:
0.001-0.01 wt%, Sr: 0.001-0.0
1 wt%, Mn: 0.5 to 1.5 wt%, Cr: 0.1
One or more of 0.5 wt% are contained, and In: 0.02-0.2 wt% and Bi: 0.05-0.
4 wt%, Sn: 0.05 to 0.4 wt%, containing one or more of them, consisting of the balance Al and unavoidable impurities, and the Fe content in the impurities is regulated to 0.01 wt% or less. It is characterized by becoming.

Each of these three types of flux-containing aluminum alloy brazing filler metal is composed of a brazing filler metal component and a flux component, and each brazing filler metal component is Al or Zn.
And main component elements of Si and Be, La, Sr, Mn
And an additional element group (hereinafter abbreviated as "Be group") having an effect of improving the corrosion resistance of Cr, and / or In, B
and an additive element group (hereinafter abbreviated as “In group”) having an effect of improving brazing properties of i and Sn.
That is, the brazing material component of the first flux-containing aluminum alloy brazing material is the main component element group and Be group, the second flux-containing aluminum alloy brazing material is the main component element group and In group, and the third flux-containing aluminum alloy brazing material. The material is composed of a main element group, a Be group, and an In group.

Al, Zn, Si which are the main element groups
Among them, Zn has the effect of lowering the melting point of the brazing filler metal, and in the brazing filler metal component composition, when the Zn content is less than 30%, it is 55
If the melting point does not fall to the point where brazing is possible at 0 ° C or lower, and if it exceeds 60 wt%, the melting point can be further lowered, but the melting temperature range of the brazing filler metal widens, and shrinkage cavities during solidification occur. There is a fear that the airtightness of the brazed portion may be deteriorated. Therefore, the Zn content is 30-60.
Must be wt%. The preferable lower limit of the Zn content is 35 wt%, and particularly 40 wt% is preferable. On the other hand, Zn
The upper limit value of is preferably 55% by weight, and particularly preferably 50% by weight. Further, Si has the effect of lowering the melting point of the brazing material and narrowing the melting temperature range. Si content is 2wt
If it is less than 8%, the above effect is poor, and if the content exceeds 8 wt%, not only the effect is saturated but also the workability is deteriorated. Therefore, the Si content needs to be 2 to 8 wt%, and the preferable lower limit of the Si content is 3 wt%, and the preferable upper limit thereof is 6 wt%.

Each element of the above Be group, Be, La, Sr,
Mn and Cr are components effective in improving the corrosion resistance by adding a trace amount. B in brazing filler metal composition
e content is less than 0.001 wt%, La content is 0.00
When the content is less than 1 wt%, the Sr content is less than 0.001 wt%, the Mn content is less than 0.5 wt% and the Cr content is less than 0.1 wt%, the effect of improving corrosion resistance is poor and the Be content is 0. The effect of improving the corrosion resistance is saturated even if the content exceeds 0.01 wt%, the La content is 0.01 wt%, the Sr content is 0.01 wt%, the Mn content is more than 1.5 wt%, and the Cr content is more than 0.5 wt%. Therefore, the Be content is 0.001 to 0.01 wt.
%, The preferable lower limit of Be content is 0.005 wt%, and the preferable upper limit is 0.008 wt%.
%. The La content is required to be 0.001 to 0.01 wt%, the preferable lower limit is 0.005 wt%, and the preferable upper limit is 0.008 wt%. The Sr content needs to be 0.001 to 0.01 wt%, the preferred lower limit is 0.005 wt%, and the preferred upper limit is 0.008 wt%. Mn content is 0.5 ~ 1.5wt
%, The preferred lower limit is 0.7 wt%, and the preferred upper limit is 1.0 wt%. The Cr content needs to be 0.1 to 0.5 wt%, the preferred lower limit is 0.13 wt%, and the preferred upper limit is 0.2 wt%.
The above trace amount additive element can improve the corrosion resistance by including at least one in the brazing filler metal composition, but it is possible to synergistically improve the corrosion resistance by using any two or more kinds in combination, and by extension, the corrosion resistance will be excellent. It becomes possible to provide accessories.

Each element of the above In group, In, Bi and S
n is a component effective in improving brazing property by adding a trace amount. In content less than 0.02 wt%, Bi
Content is less than 0.05wt%, Sn content is 0.05wt%
If less than, the brazeability improvement effect is poor,
In content is 0.2 wt%, Bi content is 0.4 wt%, S
Even if the n content exceeds 0.4 wt%, the brazing property improving effect is saturated. Therefore, the In content is 0.02-0.2 wt.
%, The preferred lower limit is 0.05 wt%, and the preferred upper limit is 0.1 wt%. The Bi content must be 0.05 to 0.4 wt%, the preferred lower limit is 0.1 wt%, and the preferred upper limit is 0.2 wt%.
Is. The Sn content must be 0.05 to 0.4 wt%, the preferred lower limit is 0.1 wt%, and the preferred upper limit is 0.2 wt%. The brazing property can be improved by including even one kind of the trace amount additive element in the brazing material component composition, but the brazing property can be synergistically improved by using any two or more kinds in combination. It is possible to provide a brazed product having excellent brazing property.

In the brazing filler metal composition, the balance of each of the above elements is Al, and the presence of unavoidable impurities is allowed, but the presence of a large amount of Fe as impurities promotes the generation of shrinkage cavities during solidification. It is necessary to regulate the Fe content to 0.01 wt% or less.

The flux component, which is another component of the flux-containing aluminum alloy brazing material, is not particularly limited as long as its melting point is not higher than the melting point of the brazing material component. Systematic or chloride based fluxes can be used. The fluoride-based flux may be, for example, a complex mixture of 45.8% KF-54.2% AlF ₃ or a complex mixture containing a eutectic composition or a composition range close to this, KAlF ₄ , K ₂ AlF. ₅ , K
₃ AlF ₆ , AlF ₃ , CsF, BiF ₃ , LiF or the like may be used. Further, as the chloride-based flux, for example, one containing BaCl ₂ , NaCl, KCl, and ZnCl ₂ as a main component is preferable, and a BaCl ₂ —NaCl—KCl ternary eutectic composition is a typical example.

Further, in the composition of the flux-containing aluminum alloy brazing material, the content ratio of the brazing material component and the flux component is 99.9: 0.1 to 7 by weight.
It needs to be 0:30. This is because when the amount of flux is less than 99.1: 0.1, sufficient flux action cannot be exhibited and good bonding becomes difficult, while 70:
This is because if the amount of flux exceeds 30 and it becomes large, it becomes brittle and solidification becomes difficult. A particularly preferable ratio of the brazing material component to the flux component is 99: 1 to 85: by weight.
15 and more preferably in the range of 98: 2 to 90:10.

The flux-containing aluminum alloy brazing material according to the present invention is generally Al powder, Zn powder, Si.
It is usually manufactured by mixing powder, brazing filler metal powder such as Be powder and flux component powder at a predetermined ratio, filling the mixed powder in a container and degassing to solidify the powder by hot pressing or the like. The density of the brazing material becomes smaller than the theoretical value calculated from each of the material powders alone due to the residual internal air. However, when the density of the brazing material becomes significantly lower than the theoretical value, although the material powder is solidified,
There is a risk that the pores will be connected to the inside and become brittle, and it is difficult to carry out secondary molding into a shape suitable for the joining material.
In practice, the function as a flux-containing aluminum alloy brazing material is inferior, and therefore it is preferably 90% or more of the theoretical value. Further, the brazing material powder and the flux material powder are preferably finely pulverized in order to uniformly mix them and densify the brazing material structure. When the flux-containing aluminum alloy brazing filler metal is manufactured by such a method, it is not always necessary to use Al, Zn, Si, Be or the like as a starting material alone, but an alloy powder or the like having a predetermined composition is used. It is good, or these may be used together.

[0018]

All of the first to third flux-containing aluminum alloy brazing filler metals according to the present invention have a low melting point of 550 since they contain Al, Zn and Si as the main components.
It can be brazed at a low temperature of ℃ or less, and since it contains a flux, it is easy to uniformly supply the flux to the joint. Further, since the Fe content is regulated to 0.01 wt% or less, shrinkage cavities during solidification are suppressed and brazing property is improved.

Further, a predetermined amount of Be, La, Sr, M
The first and third brazing filler metals containing one or more of n and Cr exhibit excellent corrosion resistance due to these effects. In addition, a predetermined amount of In, B
In the second and third brazing filler metals containing one or more of i and Sn, the brazing property which is far superior to that in the case where the Fe content is simply regulated is exerted by these actions. . Particularly, in each of the above-mentioned additional element groups, 2
The combined use of one or more kinds of materials improves synergistically the corrosion resistance or brazing property of the brazing material.

[0020]

EXAMPLES Next, specific examples of the flux-containing aluminum alloy brazing material of the present invention will be described.

As a brazing filler metal component, A having an average particle size of 44 μm
1 powder, Zn powder having an average particle size of 44 μm, average particle size of 5 μm
Si powder, Be powder with an average particle size of 1 μm, La
Powder, Sr powder, Mn powder, Cr powder, In powder, Bi
Powder and Sn powder were used. Further, as a flux component, 65 mol% AlF ₃ -3 having an average particle diameter of 15 μm
5 mol% CsF, and 55 mo with an average particle size of 15 μm
Two kinds of fluoride-based flux of 1% BiF ₃ -45 mol% LiF were used.

In producing the flux-containing aluminum alloy brazing material, the powder materials were first mixed in the proportions shown in Table 1 below to prepare mixed powder. However, the Fe content in Table 1 was not intentionally blended, but was contained as an impurity as a result of blending material powders other than Fe. Then, the mixed powder was filled in a cylindrical can made of A1100 and having a diameter of 3 inches and a height of 200 mm, and the container was sealed. The container was placed in a furnace at 400 ° C., and a pipe pinch provided on the upper part of the can. It was degassed and heated under a vacuum of 1 Torr or less. Then, the pipe pinch is welded to seal the can, and the can is kept at 400 ° C. and a maximum pressure of 4 using a hot press.
When thermocompression-molded at 00 tons, the green compact of the mixed powder was solidified and substantially integrated with the container. At this time, the height of the container solidified by pressing is 1
It became 10 mm. Then, after removing the can by cutting,
The green compact was heated to 400 ° C. in the atmosphere and extruded into a flat plate having a thickness of 3 mm and a width of 30 mm.

[0023]

[Table 1]

Corrosion tests and brazing tests were carried out on the flux-containing aluminum alloy brazing materials shown in the respective examples and comparative examples in Table 1. The corrosion test was also performed on the AC4C alloy casting material and the AC2B alloy casting material used for the brazing test.

(Corrosion test) As the flux-containing aluminum alloy brazing material, a material extruded by the above-mentioned method was once melted and solidified into a rod shape having a diameter of 10 mm and a length of 100 mm was used as a test piece. As for the alloy casting material, the same shape was used as a test piece. And JASO M6
The corrosion test was performed on each of the above test pieces based on the combined cycle corrosion test (CCT) in the 09-91 automobile material test method. Specifically, a spray test of spraying a 5% sodium chloride solution on a test piece for 2 hours at 35 ° C in the first step was performed, and in the second step, 60 ° C, 20-30% RH (relative humidity) for 4 hours. A drying test is conducted, and at the third stage, 50 ° C,
A wetting test was performed for 2 hours at 95% RH or more, and 30 cycles were carried out with this as one cycle, and then the corrosion weight loss per unit area of the test piece was obtained.

(Brazability test) The flux-containing aluminum alloy brazing material extruded by the above-mentioned method is 30 mm × 30 mm
AC4C alloy castings and AC2
The sample was placed on a flat plate of B alloy casting having a thickness of 3 mm, a width of 50 mm and a length of 50 mm, and heated at 550 ° C. for 3 minutes in a nitrogen atmosphere, and the wetting spread of the wax was observed and evaluated.

The results of these tests are shown in Table 2.

[0028]

[Table 2]

From the above test results, the flux-containing aluminum alloy brazing material according to the example of the present invention can be supplied with a predetermined amount of flux to the joint portion to achieve good brazing, and Be, La, Sr. , Mn, Cr
By adding one or more of
It was confirmed that the corrosion resistance was improved to the same level as or better than that of the B alloy casting. In particular, when two kinds of trace additive elements were used in combination, remarkable improvement in corrosion resistance was recognized. It is also presumed that the corrosion resistance of the brazed product of the AC4C alloy casting material is improved to be equal to or higher than that of the brazed product of the AC2B alloy casting material by the improvement of the corrosion resistance. Also, I
It was also confirmed that the brazing property was further improved by adding one or more of n, Bi and Sn.

[0030]

As described above, each of the first to third flux-containing aluminum alloy brazing filler metals of the present invention contains a brazing filler metal component and a flux component, and the brazing filler metal component and the flux component. Is 99. by weight.
A flux-containing aluminum alloy brazing filler metal compounded in a ratio of 9: 0.1 to 70:30, wherein the brazing filler metal component comprises Zn in an amount of 30 to 60 wt% in addition to Al as a main component.
i: 2 to 8 wt% and the Fe content in the impurities is regulated to 0.01 wt% or less.
In low-temperature brazing at a temperature of ℃ or less, a predetermined amount of flux can be easily supplied to the joint, and shrinkage cavities during solidification can be suppressed to achieve good brazing.

Further, in the first and third flux-containing aluminum alloy brazing filler metals, as the brazing filler metal component,
In addition to Al, Zn and Si, Be: 0.001 to 0.
01 wt%, La: 0.001-0.01 wt%, Sr:
0.001-0.01 wt%, Mn: 0.5-1.5 wt
%, Cr: 0.1 to 0.5 wt%, and by containing one or more of them, excellent corrosion resistance is exhibited.
In particular, when two or more of these trace additive elements are used in combination, the corrosion resistance is synergistically improved. By improving the corrosion resistance of the aluminum alloy brazing material, it is possible to improve the corrosion resistance of various brazed products of low melting point aluminum alloy materials such as AC4C alloy castings using the brazing material.

In the second and third flux-containing aluminum alloy brazing filler metals, A is used as the brazing filler metal component.
In addition to 1, Zn, and Si, In: 0.02-0.2 wt
%, Bi: 0.05 to 0.4 wt%, Sn: 0.05 to
By containing one or two or more of 0.4 wt%, the brazing property is further improved as compared with the case where the Fe content is simply regulated. In particular, when two or more kinds of these trace additive elements are used in combination, the brazing property is synergistically improved, and by extension, the quality of various brazing products of the low melting point aluminum alloy material can be improved.

Claims (3)

[Claims] 1. A flux-containing aluminum alloy braze containing a brazing material component and a flux component, and the brazing material component and the flux component being blended in a weight ratio of 99.9: 0.1 to 70:30. The brazing filler metal component is Zn: 30-60 wt%, Si: 2-
Contains 8 wt%, Be: 0.001-0.01 wt
%, La: 0.001 to 0.01 wt%, Sr: 0.00
1 to 0.01 wt%, Mn: 0.5 to 1.5 wt%, Cr:
One or more of 0.1 to 0.5 wt% is contained, the balance is Al and unavoidable impurities, and the Fe content in the impurities is regulated to 0.01 wt% or less. Aluminum alloy brazing material containing flux. 2. A flux-containing aluminum alloy braze containing a brazing material component and a flux component, and the brazing material component and the flux component being blended in a weight ratio of 99.9: 0.1 to 70:30. The brazing filler metal component is Zn: 30-60 wt%, Si: 2-
8 wt%, In: 0.02-0.2 wt%,
Bi: 0.05 to 0.4 wt%, Sn: 0.05 to 0.4
A flux-containing aluminum alloy containing at least one of wt% and consisting of balance Al and unavoidable impurities, and Fe content in the impurities being regulated to 0.01 wt% or less Material. 3. A flux-containing aluminum alloy solder containing a brazing material component and a flux component, and the brazing material component and the flux component being blended in a weight ratio of 99.9: 0.1 to 70:30. The brazing filler metal component is Zn: 30-60 wt%, Si: 2-
Contains 8 wt%, Be: 0.001-0.01 wt
%, La: 0.001 to 0.01 wt%, Sr: 0.00
1 to 0.01 wt%, Mn: 0.5 to 1.5 wt%, Cr:
One or more of 0.1 to 0.5 wt% is contained, and In: 0.02 to 0.2 wt% and Bi: 0.0
5 to 0.4 wt% and Sn: 0.05 to 0.4 wt% and one or more of them, and the balance is Al and inevitable impurities, and the Fe content in the impurities is 0.01 wt% or less. A flux-containing aluminum alloy brazing material characterized by being regulated by