JPH03114662A - Heat exchanger - Google Patents

Abstract

PURPOSE:To obtain a heat exchanger excellent in a corrosion resistance by applying an Al-Si alloy brazing filler having a limited diameter with the use of a binder for the joining of the fin and pipe of the heat exchanger and an Al alloy header incorporating more than one of Cu and Mn of a limited wt. ratio and executing the heat brazing. CONSTITUTION:By using the Al alloy material incorporating Cu and Mn for header 2, Cu and Mn allow Al and Al alloy to be noble electrochemically and the corrosion to the brazed header 2 to be prevented. The Al alloy incorporating more than one of 0.05-0.7w% Cu and 0.1-1.2wt.% Mn is therefore used. An Al-Si alloy brazing filler having 10-200mum diameter is applied with the use of a binder for the joining of a fin 3 and a pipe 1 and the header 2, heated and brazed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a heat exchanger manufactured by A that is used, for example, in automobile radiators, air conditioner condensers, evaporators, and the like.

[Background of the invention]

For example, heat exchangers that have many joints such as extruded pipes and fins, or pipes and l\＼dar, and the joints have complicated shapes, are conventionally made with Al-3i added to the core material of the layer alloy. The heat exchanger material was made of a plating sheet clad with brazing material, which was then joined by brazing. This method has excellent productivity and is practically useful because the complex core portions can be completely joined by heating at -degrees. However, if a plating sheet is used for a thin material such as a fin, the solder on the surface of the material will penetrate into the base material during heating, significantly reducing the deformation resistance of the material at high temperatures, and the brazing will easily occur due to its own weight. Due to deformation (sagging), the desired shape cannot be maintained, which may deteriorate the bonding strength in some cases. In addition, brazing is not desirable from the viewpoint that it is preferable to supply the minimum amount of solder to a part.In other words, brazing is not desirable because it is preferable to supply the minimum amount of solder to parts other than the part. Therefore, the corrosion resistance of this part is poor. In other words, ΔSi alloy solder is electrochemically responsible for pure Δ1 such as JIS 1050, and if wire type 1 is used for tubes or fins, corrosion of these materials will be accelerated and penetration will occur relatively early. Pores are formed and life is shortened.

[Disclosure of the invention]

As a result of various studies in order to improve the external corrosion resistance of extruded pipe materials covered with ^1-Si-based wax, the present inventor has developed a ^1 alloy containing Cu and Mn (a brazing sheet containing this as a core material) for the header. It has been discovered that the corrosion resistance of a heat exchanger is significantly improved when the heat exchanger is used (including the cases of 1 to 1), and the present invention has been achieved based on this finding. That is, a first object of the present invention is to provide a heat exchanger with excellent corrosion resistance. A second object of the present invention is to provide a heat exchanger in which the desired shape can be maintained because the fins are less likely to deform, and there is no problem with joint strength. Furthermore, a third object of the present invention is to provide a heat exchanger with good productivity. The object of the present invention is to provide a fin, a tube, and a 0.05 to 0.0.
A heat exchanger comprising a header made of a Δ1 alloy containing one or more selected from 7% by weight of Cu and 0.1 to 1.2% by weight of Mn, the heat exchanger comprising: The joining of the core portions is achieved by a heat exchanger characterized in that 8l-Si alloy brazing powder with a diameter of 10 to 200μI11 is applied using a binder and heated and brazed. be done. By the way, the heat exchanger of the present invention is obtained by applying a conventional flux brazing method using fluorides, chlorides, etc., and the brazing material is Al-3i alloy, Het-5i-
Zn alloy can be used, and Si in this brazing filler metal powder
The content is, for example, 7 to 12% by weight, and the Zn content is, for example, 0.
．． It is 5 to 10% by weight. The brazing temperature was set at 580 to 630°C, which is the melting temperature of the wax. If the diameter of the brazing powder is too small (less than 10 μW), the surface area of the powder will become large and the amount of oxide will increase, resulting in poor brazing properties and will be difficult to handle due to the fine powder. If it is too large, the material
In particular, it is important to set the concentration to 10 to 200 μl+ because it will not be possible to apply thinly and uniformly to bent portions. The above brazing alloy powder has little variation in composition, and
In addition, it is fine and easily melts at high temperatures, ensuring excellent brazing properties. The reason why 31 alloy material containing Cu or 14n is used for the header is that the conventionally used pure AI is electrochemically less noble than the brazing filler metal, and if the brazing filler metal corrodes, the header will be severely eroded. By preventing. That is,
Cu and Kn electrochemically enrich the Al alloy, and by using this material, the header becomes more sensitive than the solder, and the solder acts as a sacrificial anode for the header, thereby preventing corrosion. be. Here, if the Cu content is too small, less than 0.05% by weight, the above effects will not be sufficient, and conversely, even if the content exceeds 0.7% by weight, further effects will not be exhibited.
Since the corrosion resistance of the material itself deteriorates, it is important that the Cu content is within the range of 0.05 to 0.7% by weight. In addition, if the Mn content is too small (less than 0.1% by weight), the above effects will not be sufficient, and conversely, even if the Mn content exceeds 1.2% by weight, further effects will not be exhibited, and the extrusion It is important that the content of Mn is within the range of 0.1% by weight to 1.2% by weight, since this results in poor properties and lowers the productivity of the material. In addition, the fin material includes ^β-Mn alloy, Hel-14n-Z
n alloys are used.

[Examples and comparative examples]

Line type L extruded multi-hole pipe (0.5m+nt) 1 and various types ^
Assemble the header plate 2 made of A.1 as shown in FIG.
A fin (0,1+aτAt>3) having a t%Zn alloy composition was inserted. Note that the surface of the extruded multi-hole tube 1 or the bent part of the fin 3 was preliminarily coated with Al 9.1iut%5i-1 with an average grain size of 35 μm.
, 5u+t% Zn alloy brazing powder is applied using a binder made of acrylic resin. In addition, if the header is not a plating sheet, there are 8l-9, 1u+t between the extruded multi-hole tube 1 and the header plate 2 in the assembly.
A mixture of %Si wax powder and binder was applied by spraying. After spraying fluoride flux on the assembly shown in Figure 1, it was dried and heated for 6 hours in a nitrogen gas atmosphere.
Heat treatment was performed for 15 minutes at 00'C for brazing. In order to investigate the corrosion resistance of the heat exchanger obtained in this way, 72
A 0-hour CASS test was conducted, and the results are shown in Table 1. As is clear from Table 1, in the heat exchanger of the present invention, local corrosion of the header is slight. Furthermore, brazing causes almost no deformation of the fins, and the joint between the tube and the fins is also good.

[Brief explanation of drawings]

FIG. 1 is an assembly diagram of an extruded multi-hole tube, a header plate, and a fin. 1... Extruded multi-hole pipe, 2... Header plate, 3...
fin.

Claims (1)

[Claims] Fins, tubes, 0.05-0.7% by weight of Cu and 0
．． A heat exchanger comprising a header made of an Al alloy containing one or more selected from 1 to 1.2% by weight of Mn, the bonding of the core portion of this heat exchanger being 10 to 200% by weight.
1. A heat exchanger characterized in that the Al-Si alloy brazing powder having a diameter of μm is coated with a binder and heated and brazed.