JPH05277787A - Material and the joining method for joining heat exchanger parts made of aluminum - Google Patents

Abstract

PURPOSE:To assure long-term reliability and to reduce a cost by lowering the joining temp. in a brazing stage for a heat exchanger made of aluminum. CONSTITUTION:The material for joining consisting contg. 0.5 to 5.0wt.% Al and 1.5 to 10.0wt.% Sn or further, contg. one or two kinds of <=5wt.% Cu and <=0.5wt.% Ti and consisting of the balance Zn is used. This method consists in heating a part or the whole of the joining parts consisting of Al or Al alloy to 440 to 510 deg.C and joining these parts or coating at least a part of the joining parts consisting of Al or Al alloy with the material for joining, then heating a part or the whole of the joining parts to 440 to 510 deg.C and joining these parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining material for aluminum heat exchanger parts and a joining method therefor, and particularly, by lowering the joining temperature in the brazing process, ensuring long-term reliability and cost reduction. Is a measure.

[0002]

2. Description of the Related Art Since a heat exchanger made of Al or Al alloy has a complicated structure, a brazing sheet clad with an Al--Si alloy brazing filler metal is generally used as a part of a component of an assembly. The temperature is raised to about 600 ° C., which is just below the melting point of the core material, and the components are assembled by brazing in the furnace by Nocolock brazing method or vacuum brazing method.

[0003]

In general, an aluminum heat exchanger is brazed by using an Al—Si alloy brazing material in the form of a brazing sheet, so that the joining temperature is about 600 ° C.
Since it is close to the melting point of materials other than brazing filler metal,
Strict temperature control is indispensable, and since it is necessary to maintain it in a vacuum or inert gas atmosphere, equipment cost,
There is a problem that running cost is high. Also, the melting point of the brazing filler metal used for the skin material limits the material used for the core material. Further, since the clad material is used, there is a problem that the waste cannot be reused.

[0004]

As a result of various studies in view of the above, the present invention has made it possible to join aluminum heat exchanger components at a lower temperature, reduce costs, and ensure long-term reliability. The joining material and its joining method were developed.

That is, one of the bonding materials of the present invention is Al0.
5 to 5.0 wt%, Sn 1.5 to 10.0 wt%,
Alternatively, 1 of Cu 5 wt% or less and Ti 0.5 wt% or less
It is characterized in that it contains two or more species and the balance is Zn.

One of the joining methods of the present invention is Al0.5.
.About.5.0 wt%, Sn 1.5 to 10.0 wt%, or further containing one or two kinds of Cu 5 wt% or less and Ti 0.5 wt% or less, and using the bonding material consisting of the balance Zn, It is characterized in that a part or the whole of a joining part made of Al or an Al alloy is heated to 440 to 510 ° C. to join.

Further, another one of the joining methods of the present invention is Al
A bonding material containing 0.5 to 5.0 wt% and Sn 1.5 to 10.0 wt%, or further containing one or two of Cu 5 wt% or less and Ti 0.5 wt% or less, and the balance Zn. Is coated on at least a part of a joint part made of Al or an Al alloy, and then a part or the whole of the joint part is 440 to 5
It is characterized in that it is heated to 10 ° C. for bonding.

[0008]

As described above, according to the present invention, at least a part of a portion that needs to be thermally joined by using a solder or a brazing material in joining a heat exchanger component made of Al or Al alloy,
A bonding material containing 0.5 to 5.0 wt% of Al and 1.5 to 10.0 wt% of Sn, or 1 or 2 kinds of 5 wt% or less of Cu and 0.5 wt% or less of Ti, and the balance Zn. By using the joining method, a brazing sheet is not required and the joining can be performed at a lower temperature.
It is also possible to use a high-strength material having a relatively low liquidus point, such as an IS5000-based alloy (Al-Mg-based alloy), and it is possible to reduce the thickness of the joined parts.

Further, since it is also possible to form the heat exchanger parts into the shape at the time of joining and then to cover and join the above-mentioned joining material, it is possible to remove scraps such as when a joining material such as a brazing sheet is used. The problem that turning is difficult and practically impossible is solved, and the cost can be reduced due to thinning. As a method of coating the joining material, which is a Zn-based alloy, on the joint parts, hot dip plating using flux, hot dipping using ultrasonic waves in combination, etc. are economically advantageous. Alternatively, the material to be treated may be treated with zincate and then hot-dip plated.

The addition of Al in the bonding material of the present invention is performed by melting Z
n for preventing the oxidation of n, lowering the melting point, facilitating the hot dip plating and bonding work, and improving the strength and bonding strength by refining the crystal grains.
The reason for limiting the content to 5 to 5.0 wt% is that if less than 0.5 wt%, these effects are insufficient, and if it exceeds 5.0 wt%, it is good in terms of preventing oxidation of molten Zn and improving strength, Is increased to deteriorate the spreadability of the Zn-based alloy and deteriorate the workability of bonding.

The addition of Sn is to lower the melting point of the Zn-based alloy as a bonding material and improve the spreadability, hot-dip galvanizing property and bondability, and the addition amount of Sn is 1.5-10.
The reason why the amount is limited to 0 wt% is that if the amount is less than 1.5 wt%, these effects are insufficient, and if the amount exceeds 10.0 wt%, the above properties are excellent but the strength is weakened.

The addition of Cu is intended to improve the wettability between the Zn-based alloy as the joining material and the Al or Al alloy material to improve the strength, and the addition amount of Cu is limited to 5 wt% or less. The reason is that if it exceeds 5 wt%, the melting point becomes too high and the workability of joining is deteriorated.

The addition of Ti is for the purpose of preventing oxidation of the Zn-based alloy as a bonding material, improving wettability with Al or an Al alloy material, and preventing a change in color, and the addition amount of Ti is 0.5 wt%. The reason why the content is limited to the following is that if the content exceeds 0.5 wt%, the melting point becomes too high and the workability of bonding is deteriorated.

In the joining method of the present invention, the joining temperature is set to 440 to 510 ° C. for the following reason. The melting point of the Zn-based alloy that is the bonding material is approximately 410 ° C.
The reason is as follows, but if the temperature is lower than 440 ° C., the spreadability and wettability of the Zn-based alloy cannot be secured, and it is difficult to perform sound bonding. Further, when the temperature exceeds 510 ° C., overheating occurs, defects such as blowholes are likely to occur in the joint portion, and excessive heating is disadvantageous in terms of energy cost. The melting point (liquidus point) of Zn-based alloy is 360
It is preferably in the range of ˜430 ° C.

[0015]

EXAMPLES The present invention will be described below with reference to examples. JI
After forming a multi-hole tube by hot extrusion using an S1100 (Al-0.12 wt% Cu) alloy, a Zn-based alloy having the composition shown in Table 1 was also applied to the outside of the tube by using ultrasonic waves together. JIS3003 coated with a thickness of 30 to 40 μm, bent in a meandering shape, and corrugated in between.
A fin material made of an (Al-0.15 wt% Cu-1.1 wt% Mn) alloy was sandwiched and joined at the temperatures shown in Table 1 to assemble the serpentine type capacitor shown in FIG. In the figure, (1) shows a tube and (2) shows a fin. Next, for comparison, the fins are brazed sheets (the skin material is JIS40
A similar serpentine type capacitor was assembled by a conventional method using 45 (Al-10 wt% Si) brazing filler metal), and the bonding temperature at which a sound bonding portion was obtained was compared with the above-mentioned invention example. The coating temperature of the Zn-based alloy on these extruded tubes was the same as the joining temperature.

[0016]

[Table 1]

According to the example of the present invention, compared with the conventional brazing using the Al-Si alloy brazing material, about 100 to 1 is used.
Bonding can be performed at a temperature as low as 50 ° C. As a result of examining the soundness of the joint portion between the tube and the fin after forming the capacitor, it was confirmed that a joint having no defect such as a joint defect was obtained.

Although the capacitor has been described above as an example, the present invention is not limited to this, and can be applied to rooting of plates and tubes, joining of fins of radiator cores and tubes of aluminum heat exchanger parts in general. Needless to say.

[0019]

As described above, according to the present invention, the joining temperature of the aluminum heat exchanger can be lowered and the thickness of the parts can be reduced. In particular, the Zn-based alloy, which is the joining material, can be used as the tube material. On the other hand, since it has a sacrificial action on the tube material because it is electrochemically base, it has an industrially remarkable effect such that long-term reliability against pitting corrosion of the tube material can be secured.

[Brief description of drawings]

FIG. 1 is a perspective view showing a serpentine type capacitor.

[Explanation of symbols]

 1 tube 2 fins

Claims (3)

[Claims] 1. Al 0.5 to 5.0 wt%, Sn 1.5 to
Contains 10.0 wt% or further Cu 5 wt% or less, Ti
Contains 1 or 2 of 0.5 wt% or less, and balance Zn
A material for joining aluminum heat exchanger parts, which is made of 2. Al 0.5-5.0 wt%, Sn 1.5-
Contains 10.0 wt% or further Cu 5 wt% or less, Ti
Contains 1 or 2 of 0.5 wt% or less, and balance Zn
A method for joining aluminum heat exchanger parts, characterized in that a part or the whole of the joining part made of Al or an Al alloy is heated to 440 to 510 ° C. for joining using the joining material consisting of. 3. Al 0.5 to 5.0 wt%, Sn 1.5 to
Contains 10.0 wt% or further Cu 5 wt% or less, Ti
Contains 1 or 2 of 0.5 wt% or less, and balance Zn
After coating at least a part of a joining part made of Al or an Al alloy with a joining material consisting of Al, a part or the whole of the joining part is heated to 440 to 510 ° C. for joining and is made of aluminum heat. How to join exchange parts.