JPH03230889A - Aluminum alloy brazing material - Google Patents

Abstract

PURPOSE:To allow the brazing of members which are heretofore difficult to be brazed and to impart excellent tensile strength and toughness to a brazed and joined part by specifying the compsn. of an aluminum alloy brazing material. CONSTITUTION:The aluminum alloy brazing material contains 4 to 12wt.% Si, 15 to 55wt.% Zn and 0.05 to 1.0wt.% Be, and consists of the balance aluminum and unavoidable impurities. A fillet which has a low m. p., and is sufficient for the joined part by adequately flowing is formed in this way and the joining members which are heretofore difficult to be brazed are surely and securely joined.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to aluminum alloy brazing filler metals, particularly aluminum alloy castings, die castings, Aρ-Cu series, A, Q-Cu-
The present invention relates to an aluminum alloy brazing material suitably used for brazing joining members including Mg-based, A-, and Q-Zn-Mg-based high-strength alloys.

2. Description of the Related Art When joining members made of aluminum or its alloy are brazed to each other, an Aρ-Si type brazing material has conventionally been used. By the way, for example, aluminum intake manifolds for automobiles, which are formed by brazing wrought materials and cast materials, and various parts used in moving vehicles, industrial machinery, home appliances, office equipment, etc. When casting materials, die casting, high-strength alloys, etc. are included, it is necessary to use a material with a low melting point as a brazing material since the melting point of the casting materials is generally low. Therefore, conventionally, in such brazing, a brazing material made by adding zinc and copper to an AΩ-8i alloy to lower the melting point has been used, and a representative example is the 4245 alloy, which is the lowest melting point brazing material currently available. (Typical composition AJ2-10wt%Si-10wt%Zn
-3wt%Cu).

Problems to be Solved by the Invention However, even when such a brazing material is used, depending on the type of casting material, the melting point is still too high, making it difficult to perform good brazing.

In other words, when brazing a casting material such as AC4C, for example, the solidus temperature of AC4C is 577°C, so the liquidus temperature of the brazing material should be about 547°C, which is about 30°C lower. However, even the representative composition of the 4245 alloy mentioned above had a liquidus temperature of 560°C (solidus temperature of 510°C), and could not fully exhibit its function as a brazing material.

On the other hand, it is generally required that the brazing filler metal impart sufficient mechanical properties such as strength and toughness to the brazed joint.

This invention was made in view of the above circumstances, and aims to reduce the melting point of materials that are conventionally difficult to braze, such as cast materials such as AC4C, die cast materials such as ADC12, and high-strength alloys. The purpose of the present invention is to provide an aluminum alloy brazing filler metal that can be attached to a brazed joint and provide excellent tensile strength and toughness to a brazed joint.

Means for solving the problem
wt%, Be: 0.05 to 1.0 wt%,
This is achieved by using an aluminum alloy brazing material consisting of the balance aluminum and unavoidable impurities.

To explain the significance of adding each element in the brazing material of the present invention and the reason for its limitation, Si is necessary for lowering the melting point of the brazing material and increasing fluidity. However, if the content is less than 4 wt%, these effects will be poor, and if the content exceeds 12 wt%, the melting point will rise sharply, making it impossible to use it as a brazing filler metal. A particularly preferred content of Sl is 5 to 8 wt%.

Zn is an extremely effective element for lowering the melting point of brazing filler metal. However, if the content is less than 15 wt%, the effect will be poor, and if it exceeds 55 wt%, processability will deteriorate. A particularly preferable Zn content is 20 to 50 wt%.

Be contributes to improving the mechanical properties such as strength and elongation of the brazing filler metal without impairing the low melting point effect of Si, Zn, and ultimately improves the mechanical properties of the brazed joint (fillet) after brazing. It has the effect of improving. However, if it is less than 0.05 wt%, the above effects cannot be exhibited. On the other hand, if it exceeds 1.0 νt%, the effect will be saturated, resulting in economic waste. A particularly preferable content of Be is 0.10
~0.5wt%.

The method for producing the aluminum alloy brazing material according to the present invention is not particularly limited, and for example, it may be extruded into a wire rod by an extrusion method according to a conventional method, or it may be drawn into a wire rod, or hot rolling according to a conventional method. It may be manufactured into a plate material or the like by cold rolling, or any other manufacturing method may be applied. Although it is of course possible to use this brazing filler metal alone, it is also possible to use a plating sheet made of pure AΩ such as A1100.1050 or A30033003 alloy and clad with this brazing filler metal on one or both sides as a skin material. It may also be used in the form of When this brazing filler metal is used in the form of a plating sheet, it has the advantage of being easier to process than when it is used alone.

Effects of the Invention The aluminum alloy brazing material according to the present invention has a melting point much lower than that of conventionally known brazing materials by combining each element within a predetermined range. Therefore, it is useful not only for brazing aluminum wrought materials, but also for casting materials, especially casting materials with a low solidus temperature such as AC4C, die casting, and high strength alloys such as Aρ-Cu type 2219 alloy. Even when brazing, it can flow appropriately and form a sufficient fillet at the joint, making it possible to achieve reliable and strong joining of these joining members, which has been difficult in the past.

Therefore, by applying it to split casting and joining of cast materials,
It becomes possible to provide a variety of complex and thin-walled components that are not available in the past.

In addition, according to the brazing material of the present invention, it is possible to braze AΩ and SUS, etc. at a relatively low temperature, thereby suppressing the growth of a brittle alloy layer, and making it possible to braze dissimilar metals, which was not possible before. .

Furthermore, since the brazing material itself has excellent mechanical properties such as strength, it is possible to impart excellent strength and toughness to the brazed joint.

Example Next, examples of this invention will be shown.

Aluminum alloy billets having various compositions shown in Table 1 were cast by a conventional method, and then hot extruded into wire rods to obtain various brazing filler metals.

Next, the solidus temperature and liquidus temperature of each brazing filler metal obtained above were examined. In addition, tensile strength and elongation of samples Nos. 1 to 3 were measured. The results are also shown in Table 1.

Next, brazing was performed using the above-mentioned brazing material, and its brazing properties were examined. Brazing involves assembling an aluminum cast pipe made of AC4C to a pure aluminum plate so that the pipe end is in contact with the plate surface, placing each brazing filler metal near the inside of the contact area between the aluminum plate and the cast pipe, and applying chlorine. Brazing was carried out in a furnace using system flux at an ambient temperature of 560°C. Then, the state of the joint after brazing was visually observed. The results are also shown in Table 1.

Margin below L As can be seen from the results in Table 1 above, the product implementing the present invention (Sample No. 2) has a low melting point, and therefore, as is clear from the results of the brazing test, it is suitable for joining members including AC4C etc. It was confirmed that a sufficient and good fillet could be formed at the joint and excellent brazing properties could be achieved.

Moreover, since both tensile strength and elongation were excellent, it was naturally predicted that the tensile strength of the brazed joint would also be excellent. On the other hand, N without Be addition
No. 3 had poor mechanical properties, and No. 4 and conventional No. 5, in which the amount of Zn was outside the composition range of the present invention, had high melting points and were virtually impossible to braze.

In addition to the compositions listed in the table above, Afi-8wt%
S i -20wt%Z n -0,2wt%B e
SA 42-10wt%S i -50wt%Z n
-0,5wt%Be and/l-5wt%S i -30
When the same test as above was conducted for wt%Z n-0 and 1wt%Be, low solidus and liquidus temperatures, excellent mechanical properties, and a good brazed state were also obtained.

Claims (1)

[Claims] Si: 4 to 12 wt%, Zn: 15 to 55 wt%, Be
:0.05 to 1.0 wt%, the balance being aluminum and unavoidable impurities.