JPH027382B2 - - Google Patents

Description

[Detailed description of the invention]

This invention provides the following advantages when manufacturing an Al alloy heat exchanger by brazing fin material to the tube material.
This invention relates to a heat exchanger fin material made of a brazing sheet that exhibits excellent sagging resistance against heating during the brazing process. Conventionally, Al alloy heat exchangers, which are generally used in automobile radiators and air conditioners, are made by cladding an Al-Si alloy brazing material on one or both sides of an Al-Mn alloy core material. For example, the fin material that is made into a brazing sheet is
Manufactured by brazing to Al-Mn alloy tube material. However, when manufacturing the above-mentioned Al alloy heat exchanger, Si in the brazing filler metal constituting the fin material diffuses into the concentric material during brazing heating, resulting in deterioration of the sagging resistance of the fin material. This deformation of the fin material not only impairs the finish of the product, but also often causes problems such as incomplete brazing of the fin material to the pipe material. Therefore, from the above-mentioned viewpoint, the present inventors conducted research to develop a heat exchanger fin material made of a brazing sheet that does not deform during brazing heating and exhibits excellent droop resistance. The core material constituting the heat exchanger fin material consisting of a sheet is expressed in weight% (hereinafter % indicates weight%): Mn: 1 to 1.5%, Si: 0.3 to 0.9%, Zr: 0.02 to 0.2%, Ni Cr: 0.05~0.3%, Mg: 0.05~0.5%, if necessary, Cr: 0.05~0.3%, and the remainder is Al and inevitable impurities. In the resulting heat exchanger fin material, the core material that constitutes it has a structure in which various intermetallic compounds are finely and uniformly dispersed and precipitated in the base material, and due to this structure, it has a high recrystallization temperature. Because of this, the recrystallized grains of the core material are coarsened during brazing in the manufacturing process of the heat exchanger, and the intrusion of the brazing material from the grain boundaries in the core material is significantly suppressed. As a result, it was discovered that the fin material, in combination with the excellent high-temperature strength brought about by the above-mentioned structure, shows excellent sag resistance and enables good brazing. . This invention was made based on the above knowledge, and includes a core material of an Al alloy having a
In a heat exchanger fin material made of a brazing sheet made by cladding an Al-Si alloy brazing material, the core material is Mn: 1 to 1.5%, Si: 0.3 to 0.9%, Zr: 0.02 to 0.2%, Ni. Cr: 0.05~0.3%, Mg: 0.05~0.5%, and if necessary, Cr: 0.05~0.3%, with the remainder consisting of Al and inevitable impurities. This heat exchanger fin material has excellent sag resistance. Next, the reason why the composition of the core material constituting the heat exchanger fin material of the present invention is limited as described above will be explained. (a) Mn The Mn component combines with the constituent components Al, Si, Ni, etc. to form Al-Mn-Si compounds and Al-Mn-
Forms intermetallic compounds such as Si-Ni compounds,
This intermetallic compound precipitates finely and uniformly in the base material, increasing the recrystallization temperature during brazing heating,
In addition to promoting the coarsening of recrystallized grains in the core material, it also has the effect of improving the high temperature strength of this material, and as a result, it has the effect of improving the sagging resistance of the fin material. If the content is less than 1.0%, the desired effect cannot be obtained, and if the content exceeds 1.5%, no further improvement effect will be obtained. Therefore, the content was set at 1.0 to 1.5%. (b) Si The Si component has the effect of promoting the dispersion and precipitation of intermetallic compounds such as Al-Mn compounds and Ar-Zr compounds, but if its content is less than 0.3%, the desired effect cannot be achieved. No effect, while 0.9
If the content exceeds 0.3%, the sagging resistance of the fin material tends to deteriorate, so the content was set at 0.3% to 0.9%. (c) Zr The Zr component forms an Al-Zr compound that finely and uniformly disperses and precipitates in the matrix, significantly increasing the recrystallization temperature and causing re-crystallization in the core material during brazing heating. In addition to coarsening the crystal grains, the Al-Zr compound has the effect of significantly improving the sagging resistance of the fin material by improving its high-temperature strength.
If the content is less than 0.02%, the desired effect cannot be obtained, and on the other hand, if the content exceeds 0.2%, no further improvement effect will be obtained, and instead, it will be easier to form giant crystals during melting and casting, resulting in deterioration of workability. Therefore, its content was set at 0.02 to 0.2%. (d) Ni The Ni component, like the Mn and Zr components, forms Al-Ni compounds and Al-Mn-Ni compounds that are finely and uniformly dispersed and precipitated in the base material and are stable even at high temperatures, and are used as fin materials. However, if the content is less than 0.05%, the desired sagging resistance cannot be secured, while if the content exceeds 0.3%, the coarse Al-Ni Crystallized substances are more likely to form, and the recrystallization temperature decreases significantly due to the formation of coarse crystallized substances.As a result, the recrystallized grains in the core material become fine during brazing heating, and the recrystallized grains from the grain boundaries become fine. The penetration of the filler metal will be promoted and the sagging resistance of the filler metal will deteriorate, so its content should be reduced.
It was set at 0.05-0.3%. (e) Mg The Mg component has the effect of improving the strength of the core material, but if the content is less than 0.05%, the desired high strength cannot be secured, but on the other hand, if the content exceeds 0.5% Since the sagging resistance of the fin material tends to deteriorate, its content was set at 0.05 to 0.5%. (f) Cr For the Cr component, like Mn, an Al-Cr compound is dispersed and precipitated in the base material, and the recrystallized grains in the core material are coarsened during brazing heating to improve the sag resistance of the fin material. It is included as necessary when particularly excellent sagging resistance is required, but if the content is less than 0.05%, the desired effect of improving the above function cannot be obtained; on the other hand, 0.3
Even if the content exceeds 0.0%, no further improvement effect will be obtained, and instead, it will become easier to form giant crystals during melting and casting, impairing workability. Therefore, the content is set at 0.05 to 0.5%. Ta. Next, the heat exchanger fin material of the present invention will be specifically explained using examples. Al alloy 1 of the present invention for core material having the final component composition shown in Table 1, respectively, by a normal melting method.
~14, Comparative Al alloys 1 to 6 for core materials and Al alloys for brazing metal were melted and cast into ingots, and then subjected to homogenization treatment. In addition, comparative Al alloys 1 to 6 for core materials all have compositions in which the content of one of the constituent components (marked with * in Table 1) is outside the scope of the present invention. . Next, the Al alloy ingot obtained as a result was hot rolled into a plate with a thickness of 8 mm for the core material.

【table】

[Table] Hot-rolled plates, and those for brazing filler metals are similarly hot-rolled to a plate thickness of 5 mm, and the Al alloy hot-rolled plates for brazing filler metals are further cold-rolled. A cold-rolled plate with a thickness of 1 mm was used. In this state, for core material
A cold-rolled Al alloy plate for brazing filler metal was superimposed on each of the Al alloy hot-rolled plates, and both sides were clad by hot rolling to a thickness of 1.6 mm. min, holding temperature: 370°C, holding time: 2 hours, intermediate annealing is performed as appropriate between the intermediate cold rolling processes, and the final plate thickness is 0.16 mm, and the final cooling is 35%. Heat exchanger fin materials 1 to 14 of the present invention having a rolling reduction ratio of 1 to 14, and Al alloys in which the content of any one of the constituent components is outside the range of the present invention (the comparative Al alloys 1 to 6 for core material) ) Comparative heat exchanger fin materials 1 to 6 each having a core material constructed of the following were manufactured. The various heat exchanger fin materials obtained as a result were subjected to sagging resistance tests under conditions considered to be the most severe. That is, the sagging resistance test is performed using width: 30
Using a test piece with dimensions of mm x length: 140 mm,

【table】

[Table] As shown in the front view in Figure 1, this test piece 1
is inserted into the upper end of the outer flange part 2a of the horizontal F-type test piece holding jig 2, and the middle part thereof is supported by the tip of the inner flange part 2b to hold the test piece 1 inside. Hold it horizontally with a length of 40 mm protruding from the flange part 2b, and in this state,
This was carried out by holding the test piece 1 at a temperature of 625° C. for 10 minutes in a nitrogen gas atmosphere of 1 atm, which corresponds to the brazing heating conditions, and measuring the drooping amount d of the tip of the test piece 1 after the holding. The measurement results are shown in Table 2. From the results shown in Table 2, heat exchanger fin materials 1 to 14 of the present invention all exhibit excellent sagging resistance, hardly cause "sagging" or deformation during brazing, and achieve good brazing. On the other hand, as seen in Comparative Heat Exchanger Fin Materials 1 to 6, when the content of any of the constituent components deviates from the range of this invention, the sag resistance becomes poor. It is clear that it will become a thing. As mentioned above, the heat exchanger fin material of the present invention exhibits excellent sagging resistance during brazing heating, so there is almost no occurrence of "settling" or deformation, and brazing can be performed in good condition with a high yield. It is possible to do this.

[Brief explanation of drawings]

FIG. 1 is a front view showing a test piece holding jig used in the sagging resistance test. 1... Test piece, 2... Test piece holding jig, 2a,
2b...Flange part.

Claims (1)

[Claims] 1 Al-Si on one or both sides of the Al alloy core material
In the heat exchanger fin material made of a brazing sheet made by cladding the brazing filler metal of a system alloy, the above core materials are contained in weight% of Mn: 1 to 1.5%, Si: 0.3 to 0.9%, Zr: 0.02 to 0.2%, A heat exchanger fin material with excellent sag resistance characterized by being composed of an Al alloy having a composition of Ni: 0.05 to 0.3%, Mg: 0.05 to 0.5%, and the remainder consisting of Al and inevitable impurities. . 2 Al-Si on one or both sides of the Al alloy core material
In the heat exchanger fin material made of a brazing sheet made by cladding the brazing filler metal of a system alloy, the above core materials are contained in weight% of Mn: 1 to 1.5%, Si: 0.3 to 0.9%, Zr: 0.02 to 0.2%, Ni: 0.05 to 0.3%, Mg: 0.05 to 0.5%, Cr: 0.05 to 0.3%, and the rest is Al and inevitable impurities. Excellent heat exchanger fin material.