JPH0472032A - Aluminum fin material for automobile heat exchanger - Google Patents

Abstract

PURPOSE:To obtain an Al alloy having excellent heat conductivity and furthermore excellent in strength at the time of thinning by adding specified allay elements to Al. CONSTITUTION:As a fin material for an automobile heat exchanger, an Al alloy having a compsn. contg., by weight, 0.2 to 1.0% Si and 0.05 to 0.5% Mg, or furthermore contg. 0.03 to 0.3% Zr or one or >= two kinds among 0.5 to 3.0% Zn, 0.01 to 0.1% In and 0.01 to 0.1% Sn independently or compositely and the balance Al is used. The Al allay for a fin material easily thinnable and small in the deterioration of strength at the time of the thinning as well as excellent in heat conductivity can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aluminum fin material used in a heat exchanger for an automobile.

[Conventional technology]

As shown in FIG. 1, an automobile heat exchanger is manufactured by brazing and joining an electric resistance welded tube made of a plating sheet clad with a brazing material on the outside to fin materials, hengoo materials, and the like.

This fin material requires appropriate strength to be processed at room temperature, such as corrugated processing and assembly with tube material.

Its strength is approximately 14 to 18 kgf/lj.

In addition, since it is exposed to high temperatures of 600°C during brazing, the thinnest fin material may be deformed due to the restraint of the tube material and steel jig, resulting in core deformation and brazing conditions. High temperature strength and sagging resistance are required.

Furthermore, excellent thermal conductivity is required to ensure heat exchange performance.

What is currently mainly used as a material that satisfies these required qualities is A1-Mn-based 3003 alloy or an alloy in which Zn and In+Sn are added to this alloy.

[Problem to be solved by the invention]

However, recently automatic heat exchangers have become more compact and have improved performance (
There is a strong demand for improvements in heat dissipation characteristics.
For this reason, it is necessary to further reduce the thickness of the fin material and improve its thermal conductivity.

3003, which has been conventionally used for such situations.
In terms of strength, alloys can be made thinner, but when the walls are made thinner, heat dissipation decreases due to a decrease in the fin cross-sectional area.
It is necessary to improve thermal conductivity.

However, this 3003 series alloy has about 1.1 wt% of Mn added, and due to the solid solution of Mn in the alloy, the electrical conductivity, which indicates thermal conductivity, is about 38%lAC3, which is among the lowest among aluminum alloys. There is a problem in that thermal conductivity is an obstacle to improving performance.

[Means to solve the problem]

The present invention was developed as a result of intensive studies to solve this problem, and the invention of claim 1 is based on Si0.2-1
．． 0iyt% and Mg 0.05 to 0.5t%, and the balance A1 and unavoidable impurities. 2-1.011t%, Mg
0.05-0.5wt% and Zr 0.03-0.3
An aluminum fin material for an automobile heat exchanger, characterized in that the aluminum fin material contains 5iO02 to 1.0 wt%, and the remainder consists of Aj2 and unavoidable impurities.
@t% and Mg0.05-0.5wt%, and further contains Zn0.5-3.0wt%, In0.01-0.
An aluminum fin material for an automobile heat exchanger, characterized in that the aluminum fin material contains one or more of 1wt% and 0.01 to 0.1ist% of Sn, and the remainder consists of AI2 and unavoidable impurities. The invention of No. 4 is S i0
．． 2 to 1.0 wt%, Mg 0.05 to 0.5 wt%, and Zr 0.03 to 0.3 wt%, and further Zn
0.5-3.0wt%, In 0.01-0.1wt%
, one or two of Sn 0.01-0.1wt%
This is an aluminum fin material for an automobile heat exchanger, which is characterized in that it contains at least 10% of the aluminum fin material, and the remainder consists of Af and unavoidable impurities.

[Effect]

The reason for adding each additive element and the reason for limitation in the present invention are as follows.

Si has the effect of improving material strength by solid solution in An and precipitation of a compound (MgzSi) with M, but the amount added is limited to 0.2 to 1.0 wt%.
If it is less than 1.0 wt%, the effect will not be sufficient, and if it exceeds 1.0 wt%, the melting point will rise, causing trouble in brazing, and the thermal conductivity will also decrease.

Like Si, Mg can be dissolved in Al as a solid solution and as a compound with St (
The precipitation of MgzSi ) has the effect of improving material strength. The amount added was limited to 0.05 to 0.5 wt% because less than 0.05 wt% is ineffective.
If it exceeds %, the brazing properties will deteriorate, and when a fluoride flux is used, a Mg-F compound will be formed, which will significantly reduce the oxide film-destroying effect of the flux.

Zr is effective in improving material strength and sagging resistance.

It also has the effect of coarsening the grain size and preventing deformation at high temperatures. The addition amount was limited to 0.03 to 0.3 wt% because it is ineffective if it is less than 0.03 wt%.
%, plastic workability and thermal conductivity decrease. In addition, Cr, Ti, and Mn have the same effect as Zr, so one or more of these can be added at 0.03
~0.3 wt% may be added.

Zn, In, and Sn all have the effect of making the potential of the fin material less noble and increase the sacrificial anode effect. The amount of Zn added
0.5-3.0wt%, In 0.01-0.1wt
% and Sn 0.01 to 0.1 wt% because below the lower limit, there is no effect, and above the upper limit, the effect is saturated.

〔Example〕

Next, 21 types of pair fins having the alloy components shown in Table 1, which will further specifically explain the present invention with reference to Examples, were fabricated by the following method.

After melting and mold casting in a conventional manner, both sides were faced and 52
Perform homogenization treatment at 0°C for 3 hours, then further heat at 500°
C was hot rolled to a thickness of 5m, and then cold rolled to a thickness of 0.5m.
After the fin material had a thickness of 15 mm, it was subjected to intermediate annealing at 380°C for 2 hours, and finally cold rolled to obtain a fin material with a thickness of 0.1 m. Note that the amount of Fe as an impurity was 0.3 ht%.

After brazing the above fin material in the atmosphere at 600'CX 10ml, the tensile strength and electrical conductivity were measured. In addition, a 3003 core plating sheet (1,000 tm thick) is corrugated to a width of 15 mm, a fin height of 10 mm, and a pitch of 2.5 mws, and coated with 4343 brazing filler metal on both sides at a clad ratio of 10%. As shown in Figure 2, the silk is combined with fluoride Franks (K, 6I! F4, Al, F,
A mixture of (a mixture of) was applied at a concentration of 3%, and after drying, brazing properties were investigated by applying brazing heat at 600° C. x 3 rn in a N2 atmosphere. Brazing property was evaluated by evaluating the bonding condition between the fin and plating sheet and the presence or absence of buckling of the fin.

In addition, the brazed core is tested by CASS (JIS) for 200 hours.
H8681), and the depth of focus generated on the praising sheet was measured by the depth of focus method. The results are shown in Table 2.

As is clear from Table 1 and Table 2, Examples N111 to 13 of the present invention have a strength after brazing of 9 kgf/- or more, and a 50% lAC
It has an electrical conductivity of 3 or more, and its brazing properties and sacrificial anode action are similar to those of the conventional material 21.

On the other hand, comparative example Nci14.1 with low Si and Mg content
Comparative example Na16, which has a large amount of Mg, generates a large amount of reaction products with the fluoride flux and cannot be brazed, and comparative side stone 17, which has a large amount of Si, has difficulty bonding with the tube during brazing. There were problems with brazing properties, such as melting at joints and crushing of the core. Further, in Comparative Example klB, 19.20, which has a large amount of Zn, In, and Sn, corrosion of the fins is significant, and there is a risk that the core structure will be destroyed due to self-corrosion of the fins during a long-term corrosion resistance test.

〔Effect of the invention〕

As mentioned above, the fin material of the present invention has fin strength after brazing and sacrificial anode action comparable to conventional materials, and has significantly superior heat exchange performance than conventional materials, and has a remarkable industrial effect. be.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a heat exchanger for an automobile, and FIG. 2 is a combination diagram of a fin material and plating sheet used in an example. DESCRIPTION OF SYMBOLS 1... Fin, 2... ERW pipe, 3... Header plate, 4... Resin tank, 5... Placing sheet.

Claims (1)

[Claims] 1) Si0.2-1.0wt% and Mg0.05-0
．． An aluminum fin material for an automobile heat exchanger, characterized in that the aluminum fin material contains 5 wt% and the remainder consists of Al and unavoidable impurities. 2) Si0.2-1.0wt%, Mg0.05-0.5
An aluminum fin material for an automobile heat exchanger, characterized in that it contains 0.03 to 0.3 wt% of Zr and 0.03 to 0.3 wt% of Zr, and the remainder consists of Al and inevitable impurities. 3) Si0.2-1.0wt% and Mg0.05-0
．． 5 wt%, further Zn0.5 to 3.0 wt%,
In0.01~0.1wt%, Sn0.01~0.1w
An aluminum fin material for an automobile heat exchanger, characterized in that the aluminum fin material contains one or more of t% and the remainder consists of Al and unavoidable impurities. 4) Si0.2-1.0wt%, Mg0.05-0.5
wt% and Zr0.03-0.3wt%, and further contains Zn0.5-3.0wt%, In0.01-0.1w
An aluminum fin material for an automobile heat exchanger, characterized in that the aluminum fin material contains one or more of t% and Sn0.01 to 0.1wt%, and the remainder consists of Al and unavoidable impurities.