JPS59185757A - Fin material for aluminum heat exchanger manufactured by vacuum brazing - Google Patents

Abstract

PURPOSE:To obtain the titled fin material having improved corrosion resistance and an improved sacrificial anode effect by adding restricted amounts of Sn and Zn to Al or by further adding Mg and Mn, Zr or Cr. CONSTITUTION:This fin material for an Al heat exchanger manufactured by vacuum brazing consists of, by weight, 0.02-0.1% Sn, 0.04-0.09% Zn and the balance Al with inevitable impurities or further contains 0.05-1% Mg and one or more among 0.1-1.5% Mn, 0.02-0.2% Zr and 0.02-0.3% Cr. The fin material having said alloy composition is electrochemically base, has superior corrosion resistance, and prevents well the corrosion of a tube material by the significant sacrificial anode effect. The heat exchanger can be used for a long period because of the corrosion resistance of the tube and fin materials.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fin material with excellent corrosion resistance and sacrificial anode effect, which is used in manufacturing aluminum heat exchangers by vacuum brazing.

Conventionally, aluminum heat exchangers have been widely used, for example, in automobile radiators, air conditioners, and the like. This heat exchanger is usually made of fin material with a purity of 9
9.70% or more M (J engineering 51070 material) or purity:
A thin plate of 99.80% or more M (J engineering S1080 material) or these thin plates is used as a core material, and both sides of this core material are coated with U-
Either a phrasing sheet made of 8i alloy brazing material cladding is used, and the pipe material is M-M, which is formed by brazing or extrusion.
N-based alloy tube material or M-Mn-based alloy as core material,
A composite tube material made by cladding an Ag-8i alloy brazing filler metal on the surface of this core material is used, and these fin materials and tube materials are
They are manufactured by assembling them together in the presence of a brazing material, assembling them into a heat exchanger shape, and vacuum brazing them in this state.

However, in this conventional heat exchanger, the corrosion resistance of the fin material is poor, and the sacrificial anode effect of the fin material on the tube material is not sufficiently satisfactory, so that the service life is reached in a relatively short period of time.

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to develop a fin material that has excellent corrosion resistance and has an excellent sacrificial anode effect, that is, is electrochemically less noble than pipe material. As a result, it contained, in weight%, Eln: 0.02 to 0.1%, Zn: 0.04 to 0.09%, and, if necessary, Mg: 0.05 to 1%, Mn: 0.1-1.5%, Zr: 0.02-0.2%, Cr: 0.02-0.3%, and the remaining 9 contains M. M alloys with a composition consisting of unavoidable impurities have superior corrosion resistance and electrochemically less noble properties than pure M materials such as 1070 and 1080 materials. When used as a fin material in an exchanger, the excellent sacrificial anode effect protects the pipe material from corrosion, and the excellent corrosion resistance and corrosion resistance of the fin material itself means that the heat exchanger can be used for an extremely long period of time. I found out that it is possible.

Therefore, this invention has been made based on the above knowledge, and the reason why the component composition is limited to the above general composition will be explained below.

(') The 5n Sn component has the effect of making the fin material electrochemically less noble, thereby exerting an excellent sacrificial anode effect on the tube material, but if its content is less than 0.02%, the above effect will not be achieved. The desired effect cannot be obtained, and on the other hand, even if the content exceeds 0.14, no further improvement effect will appear due to the above action, and the corrosion resistance will deteriorate rather strongly. L& was set at 0.02 to 0.1.

(b) Zn The Zn component has the effect of significantly improving the corrosion resistance of the fin material, but if its content is less than 0.04%, the desired excellent corrosion resistance cannot be secured; ．． 09
Even if Zn is contained in excess of 5%, not only will no further improvement in corrosion resistance be seen, but vacuum brazing will result in significant evaporation of Zn, leading to problems such as furnace contamination. The content was determined to be 0.04% to 0.09%.

(c) Mg The Mg component not only impairs the sacrificial anode effect of the fin material, but also has the effect of further improving corrosion resistance. However, if the content is less than 0.05%, the desired effect of improving corrosion resistance cannot be obtained.On the other hand, if the content exceeds 1%, the effect of improving corrosion resistance will not be saturated; Since the high temperature sagging resistance decreases, the content 'io was determined to be 05 to 1%.

(d) Mn, Cr, and Zr These components have the effect of particularly improving high-temperature strength, thereby further improving the sagging resistance of the fin material, which is sometimes required for vacuum brazing, so they are excellent materials. It is contained as necessary when drooping resistance is required, but the content is Mn: less than 0.1%, Or: 0.02%, respectively.
% and Zr: less than 0.02%, the desired high temperature strength improvement effect cannot be obtained, while Mn: 1.5%, Or: 0
．． Mn: 0.1-1.5%, Cr: 0.1% to 1.5%, Cr: 0.1% to 1.5%, Cr: 0.1% to 1.5%, Cr: 0.1% to 1.5%, Cr: 0.1% to 1.5%, Cr: 0.1% to 1.5%, and Zr dicrystallized products, etc.
: 0.02-0.3%, and Zr: 0.02-0
．． It was set at 2%.

Note that the fin material of the present invention contains F as an unavoidable impurity.
e: 0.5% or less, Si: Q, 3% or less, Ou: 0.0
3% or less or Ti: 0.03% or less may be contained, but as long as these allowable values are not exceeded, the properties of the 9 fin material will not be impaired in any way.

Next, the fin material of the present invention will be specifically explained using examples.

Examples M alloys 1 to 20 for fin materials of the present invention and M alloys 1 to 3 for comparative fin materials, each having the composition shown in Table 1, were prepared by a conventional melting method. M alloy for pipe material and M for brazing material
After preparing and casting a molten alloy, it was subjected to homogenization heat treatment, and after the face side was subjected to hot rolling to obtain a hot rolled sheet with a thickness of 8 mm, and then this M for fin material of the present invention was prepared. Alloy 1
~20 and comparison fin material M alloys 1 to 3 are cold rolled to a thickness of 0.2 van by cold rolling a part of the hot rolled sheets. ~3
was manufactured. In addition, some of the hot-rolled sheets of M alloy for pipe materials and the hot-rolled sheets of M alloy for brazing filler metal are cold-rolled to a thickness of 1 m (hereinafter the former will be referred to as thin sheets for pipe materials). And so. Next, the remaining M alloys 1 to 20 for fin materials of the present invention
Comparatively, all cold-rolled plates of the above-mentioned M alloy for brazing filler metal were laminated on both sides of each of the hot-rolled plates of M alloys 1 to 3 for fin material, hot rolled in this state to clad, and then Composite fin materials 1 to 20 of the present invention and comparative composite fin materials 1 to 3 each having a plate thickness of 0.2 wn were manufactured by cold rolling. Furthermore, regarding the remaining hot-rolled sheet of the above-mentioned M alloy for pipe material, a cold-rolled sheet of the above-mentioned M-alloy for brazing material is superimposed on one side thereof, and in this state, hot rolling is performed to clad it, and further cold rolling is performed. A composite thin plate for pipe material having a plate thickness of 1 mm was manufactured by applying the following steps.

Next, the resulting fin materials of the present invention 1 to 20, comparative fin materials 1 to 32, composite fin materials of the present invention 1 to 20. A test piece was cut out from each of Comparative Composite Fin Materials 1 to 3, and the test piece was held at a temperature of 600°C for 10 minutes in a vacuum, and then subjected to forced cooling heat treatment.
Immersed in saline solution with a concentration of 5.5%, l mA/cr
Measure the dissolution potential with an anodic current of l applied,
The remaining test pieces were immersed in saline solution adjusted to pH 3 for 20 hours, and the corrosion weight loss after the test was measured.

In addition, the present invention fin materials 1 to 269 and the comparative fin materials 1
~3, composite thin plate for pipe material, and composite fin material of the present invention 1~
20 and comparative composite fin materials 1 to 3 and the thin plate for pipe material,
Fin material dimensions: 30mm x 80+nm, tube material thin plate and composite thin plate dimensions: 50 wm x 80 tM
rl, assemble the fin material upright along the longitudinal center line of the thin pipe material plate placed horizontally, and in this state, heat the fin material in a vacuum of 10 torr at a temperature of 600°C for 10 minutes.
Vacuum brazing was carried out under the condition of holding for 50 minutes, and the test piece after vacuum brazing was subjected to 0ASS test for 500 hours to measure the number of pitting corrosion and maximum pitting depth of the thin pipe plate or composite thin plate, The state of erosion of the wood was observed.

In addition, the corrosion state is extremely slight corrosion: ◎ mark,
Those with normal corrosion are marked with ○, those with relatively large amount of corrosion are marked with △, those with significant corrosion are marked with x, and those with only a small amount of fin material remaining are marked with XX. These results are shown in Table 2.

From the results shown in Table 2, it can be seen that the fin materials 1 to 20 of the present invention and the composite fin materials 1 to 20 of the present invention all have excellent corrosion resistance and electrochemically abrasive properties. Comparative fin materials 1 to 3 and comparative composite fin materials 1 to 3, which do not contain Sn and/or Zn, exhibit an excellent sacrificial anode effect and sufficiently protect the pipe material from corrosion. It is clear that at least one of the corrosion resistance and the sacrificial anode effect is inferior.

As mentioned above, the fin material of the present invention has excellent corrosion resistance and also has an excellent sacrificial anode effect, so when it is put into practical use, it will protect the pipe material well from corrosion.
Coupled with the excellent corrosion resistance of the fin material itself, it has industrially useful properties such as allowing heat exchangers to be used for an extremely long period of time.

Applicant: Mitsubishi Aluminum Corporation Agent Tomi 1) Kazuo and 1 other person 243-

Claims (4)

[Claims] (1) A vacuum containing Sn: 0102 to 0.1%, Zn: 0.04 to 0.09%, and having a composition (the above weight %) with the remainder consisting of M and unavoidable impurities. Fin material for aluminum heat exchangers manufactured by brazing. (2) Contains Sn: 0102-0.1%, Zn: 0.04-0.09%, and further contains Mg: 0.05-1%, with the remainder being free from M and inevitable impurities. A fin material for an aluminum heat exchanger manufactured by vacuum brazing, characterized by having a composition (the above weight %). (3) Sn: 0.02-0.1%, Zn: 0.
04 to 0.09%, and further contains Mn: 0.1 to 1.5%, Zr: 0.02 to 0.2%, Or: 0. Manufactured by vacuum brazing, characterized in that it contains one or more of the following: '02 to 0.3%, with the remainder consisting of M and unavoidable impurities (weight percent). Fin material for aluminum heat exchangers. (4) Sn: 0.02-0.1%, Zn: 0.0
4 to 0.09%, and further contains one of the following: Mn: 0.1 to 1.5%, Zr: 0.02 to 0.2%, Cr: 0.02 to 0.3%. Manufactured by vacuum brazing, characterized in that it contains two or more species, Mg: 0.05 to 1, and the remainder has a composition (by weight %) of M and unavoidable impurities. Fin material for aluminum heat exchangers.