JPH06104875B2 - Al alloy fin material for heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is excellent in high-temperature strength during brazing and also excellent in room-temperature strength after brazing (hereinafter referred to as room-temperature strength), and further excellent sacrificial anode. The present invention relates to an Al alloy fin material for a heat exchanger that also has an effect.

[Prior Art] Al and Al alloys are widely used as tube materials and fin materials for automobile heat exchangers such as car air conditioners and radiators. Most of such heat exchangers use the above-mentioned component as Al.
-Manufactured by using a Si-based alloy as a brazing material.

[Problems to be solved by the invention]

However, during this brazing, each member is kept at a high temperature of 600 ° C or higher. Therefore, the conventional Al alloy fin material is plastically deformed by the restraint force or the self-weight of the jig when brazing with the pipe material, and as designed. Since the size and shape of the heat exchanger cannot be given to the heat exchanger, there is a problem that when the heat exchanger is used, the air flow is obstructed to lower the heat exchange performance, and in some cases, it becomes difficult to mount.

Further, in these heat exchangers, there is a strong demand for thinning the fin material in order to reduce the weight, but in the conventional Al alloy fin material, the strength after brazing is not sufficient, and if the thickness is reduced, the heat There is a problem that plastic deformation occurs due to the flow of air when the exchanger is used, which obstructs the flow of air and reduces heat exchange performance.

[Means for solving problems]

Therefore, the inventors of the present invention conducted research to develop an Al alloy fin material having excellent strength at room temperature and high temperature from the above viewpoints, and as a result, Mn: more than 1.5% to 2%, Si: 0.3 to 0.75 %, Mg: 0.41 to 1.3%, Zr: 0.03 to 0.15%, Zn: 0.1 to 2%, and, if necessary, Cr: 0.03% to 0.3%, with the balance being Al. The fin material composed of an Al alloy that has a composition of inevitable impurities (above wt%) has excellent room temperature and high temperature strength due to the Mn and Si, and Zr that compose this alloy, and further improves the room temperature due to Mg. The strength is improved, and the addition of Cr further promotes the above-mentioned action brought about by Mn, Si, and Zr, and Zn makes the alloy itself electrochemically base, resulting in an excellent sacrificial anode. Will have an effect and therefore this Al alloy fin material Has obtained the knowledge that there is no plastic deformation during brazing and that it can sufficiently cope with weight reduction.

The present invention has been made based on the above findings, and the reason why the component composition ranges are limited as described above will be described below.

(A) Mn The Mn component has the function of improving not only the room temperature strength but also the high temperature strength when kept at the temperature in the furnace during brazing by being contained together with Si. This is due to the presence of Al-Mn-Si-based fine compounds that are stable even at high temperatures. That is, in the Al-Mn-based alloy, when the Mn content exceeds 1.5% by weight, a large amount of coarse Al-Mn compound is formed and the workability is deteriorated.
When Si is contained as an alloy component in this, the composition of the above-mentioned compound changes, and the compound itself finely and uniformly disperses, so that it has excellent room temperature and high temperature strength. However, if the content is 1.5 wt% or less, S
The desired high strength cannot be ensured in relation to the i content, and even if the content exceeds 2% by weight, the effect of further improving the strength cannot be obtained, but rather a giant crystal is formed. Since the workability is deteriorated, the content thereof is set to more than 1.5% by weight to 2% by weight.

(B) Si Si is an essential component for ensuring high strength as described above when contained together with Mn. However, if the content is less than 0.3% by weight, desired high strength can be secured. However, if its content exceeds 0.75%, Al-Mn-
Since a coarsening tendency appears in the Si compound, which causes a decrease in strength, the content was set to 0.3 to less than 0.75% by weight.

(C) The Mg Mg component has the effect of improving the room temperature strength of the fin material by solid solution hardening, and the effect exhibited with the increase of the content also increases, but especially when the fin material is thinned. 0 when sufficient room temperature strength is required.
Must contain at least 41% by weight. Further, when Mg having such a content is contained together with Zn, the electric potential becomes effectively base, and an excellent sacrificial anode effect can be exhibited. Therefore, if its content is less than 0.41% by weight,
It is not possible to secure the desired excellent room temperature strength and sacrificial anode effect, and if the content exceeds 1.3% by weight, the workability will decrease, so the content should be 0.41 to 1.3% by weight. I decided.

(D) Zr Zr component binds to Al to form a fine compound in a dispersed manner, thereby further enhancing the strength improving effect provided by the Al-Mn-Si compound, and further improving the normal temperature and high temperature strength. However, if the content is less than 0.03% by weight, the desired strength-improving effect cannot be obtained, while if the content exceeds 0.15% by weight, the workability deteriorates. Was set to 0.03 to 0.15% by weight.

(E) For the Zn Zn component, the fin material is made electrochemically base,
It has an effect of giving an excellent sacrificial anode effect, but if its content is less than 0.1% by weight, the effect is not sufficient,
On the other hand, even if the content exceeds 2% by weight, the further effect cannot be exhibited, so the content was set to 0.1 to 2% by weight. It should be noted that this content does not essentially affect workability, strength, and the like.

(F) Cr The Cr component has the action of forming an Al-Cr-based fine compound that disperses in the matrix similarly to Zr, and further improves the room temperature and high temperature strength, so it is contained as necessary. If the content is less than 0.03% by weight, the desired strength-improving effect cannot be obtained, while if the content exceeds 0.3% by weight, the workability is deteriorated, so the content is 0.03 to 0.
Determined to be 3% by weight.

〔Example〕

Next, the Al alloy fin material of the present invention will be described with reference to examples.

Using a normal melting furnace, adjusting the molten metal having the component composition shown in Tables 1 to 3, respectively, after casting to form an ingot,
After homogenizing heat treatment under normal conditions, and then chamfering this ingot, hot-rolled to a hot-rolled sheet with a thickness of 3 mm, and then cold-rolling while adding appropriate intermediate annealing. As a result, the present invention Al alloy fin materials 1 to 12 and comparative Al alloy fin materials 1 to 4 each having a plate thickness of 0.1 mm were manufactured.

In each of the comparative Al alloy fin materials 1 to 4, a composition having a component content (marked with * in Table 3) that influences the strength of the constituent components deviates from the range of the present invention to the lower side. It has.

Then, from the various fin materials obtained as a result, a tensile test piece with a parallel part width: 7 mm × parallel part length: 15 mm was made, and a tensile test was conducted in an atmospheric furnace at 600 ° C to measure the high temperature tensile strength. did.

Also, test pieces with a width of 20 mm and a length of 80 mm were cut out from the various fin materials described above and cut in a vacuum of 10 ^-4 torr and in a nitrogen gas atmosphere.
After heat treatment under conditions equivalent to brazing at 0 ° C. for 5 minutes and cooling to room temperature, A room temperature tensile test was performed. . Further, for the test pieces which were subjected to the heat treatment corresponding to the above brazing of the present invention Al alloy fin materials 1 to 12 and comparative Al alloy fin materials 1 to 4, the concentration: 3.5
Pitting potential was measured in% saline. The above results are summarized in Tables 1 to 3.

〔The invention's effect〕

From the results shown in Tables 1 to 3, the Al alloy fin materials 1 to 12 of the present invention are all excellent in high temperature strength and particularly excellent in room temperature strength, and further, by containing Zn, the high temperature strength and room temperature strength are improved. It is clear that the pitting potential becomes more base while maintaining a high level, and that it has an excellent sacrificial anode effect.

On the other hand, as seen in the comparative Al alloy fin materials 1 to 4, when the content of any one of the strength improving components among the constituent components deviates from the range of the present invention to the lower side, at least the high temperature strength and the room temperature strength are obtained. It is clear that either will come down.

As described above, the Al alloy fin material of the present invention has excellent high-temperature strength and normal-temperature strength, and further has an excellent sacrificial anode effect. The shape of the heat exchanger can be reduced because the members can be easily thinned, and the tube body can be protected by the excellent sacrificial anode effect. It has industrially useful properties such as the ability to significantly extend the service life of.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yu Takeuchi 67-7 Futatsuya, Susono City, Shizuoka Prefecture (56) References JP-A-55-140098 (JP, A) JP-A-56-142845 (JP, A) JP-A-58-64339 (JP, A)

Claims (2)

[Claims] 1. By weight%, Mn: more than 1.5% to 2%, Si: 0.3 to less than 0.75%, Mg: 0.41 to 1.3%, Zr: 0.03 to 0.15%, Zn: 0.1 to 2%, An Al alloy fin material for a heat exchanger, which is excellent in room temperature and high temperature strength and has a sacrificial anode effect, characterized by being composed of an Al alloy having the composition of Al and the unavoidable impurities. 2. By weight%, Mn: more than 1.5% to 2%, Si: 0.3 to less than 0.75%, Mg: 0.41 to 1.3%, Zr: 0.03 to 0.15%, Zn: 0.1 to 2%, , And further, Cr: 0.03% to 0.3%, and the balance is composed of an Al alloy having a composition consisting of Al and unavoidable impurities. Aluminum alloy fin material for ware.