JPH0483844A - Al and al alloy for heat exchanger fin material by brazing - Google Patents

Abstract

PURPOSE:To improve the heat conductivity of a fin material by using Al in which the content of Fe and Si components is regulated to prescribed one or below. CONSTITUTION:This is Al for a heat exchanger fin material by brazing constituted of <=0.2% Fe, <=0.1% Si and the balance Al with inevitable impurities, by which a fin material excellent in heat conductivity can be obtd. Furthermore, the allay obtd. by independently or compositely adding 0.01 to 0.3$ Zr and 0.01 to 0.3% Cr to the Al, in which the content of Fe and Si is regulated to the above range has improved buckling resistance while it maintains heat conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to Aff and A2 alloys for fin materials of AI2 heat exchangers bonded by brazing. This invention relates to β and Al2 alloys for fin materials that can improve the heat exchange efficiency (cooling capacity) of exchangers.

AJ2 heat exchanger made by brazing generally consists of a passage (hereinafter referred to as a tube) for passing a refrigerant such as water and fins for dissipating heat. A hole tube or an electric resistance welded flat tube made of a plating sheet clad with an Aβ-Si brazing material is used. As the fin material, a plating sheet made of a core material 1 clad with A°C-3i brazing material 2 on both sides, as shown in Figure 1, or a bare fin material without cladding with a brazing material 2 is used. ing.

A specific example of a brazed heat exchanger made of helium is shown in FIG. In FIG. 2(A), the evaporator (B) is a condenser, and both are made by combining the extruded flat multi-hole tube 3 and the fin material of the plating sheet shown in FIG. (C) is a radiator, and an ERW flat tube 3 is made from a plating sheet clad with Aj2-3i brazing material on one side, and this tube (brazing material is on the outside of the tube) is connected to bare fin material. It is a combination. The tubes and corrugated fins of these heat exchangers are assembled by flux brazing, vacuum brazing, or inert gas atmosphere brazing at a temperature of about 600°C.

By the way, in conventional AJZ heat exchangers made by such brazing, Ag-M, which has good buckling resistance, was used as the fin material 4.
N-based alloys, such as 3003 alloy (A A -0,05~
0.20wt%Cu-1.0~1.5wt%Mn alloy [hereinafter wt% is simply abbreviated as %]) or 3203 alloy (
A fl -1.0~1.5% Mn alloy) is used as a core material, and an Al2-Si alloy brazing filler metal (Ag-5~12
%Si alloy)Ag2. -Si -Mg alloy filler metal (Ag
2. -5 to 12% 5i-0,5 to 2% Mg alloy), etc., with a thickness of 0.1 to 0.2 mm (plating sheet), or the above 300 with a thickness of 0.1 to 0.2 mm.
A bare sheet of 3.3203 alloy is used.

However, Ag such as 3003 alloy and 3203 alloy
- Although the fin material 4 made of Mn-based alloy has excellent buckling resistance, it cannot necessarily be said that it has high thermal conductivity, and this was the cause of poor heat dissipation of a heat exchanger using this fin material. .

On the other hand, in recent years, heat exchangers, especially those for automobiles, have become lighter and smaller, and there is a demand for thinner fins and improved heat exchanger performance, that is, improved heat exchange efficiency (cooling capacity). ing.

Therefore, there is an increasing demand for the development of fin materials that have various properties such as (1) excellent thermal conductivity, and (2) no fin settling or deformation during brazing bonding.

As a result of extensive research to develop a fin material that meets these requirements, the present inventors found that Fe and S in Ag
The thermal conductivity of the fin material can be improved by using Ag2 in which the content of the i component is regulated below a predetermined amount, and furthermore, by adding a predetermined amount of Zr or Cr to this, the buckling resistance of the fin material can be improved. We have discovered that it is possible to further improve performance. The present invention has been made based on this knowledge.

That is, the present invention provides (1) a heat exchanger fin material Aj2 (hereinafter referred to as first
(2) Fe 0.2% or less, Si 0.1% or less, Z
A heat exchanger fin formed by brazing and joining, characterized in that it contains one or two of r0.01-0.3% and Cr 0.01-0.3%, with the remainder being octabeta and inevitable impurities. This invention provides an Ag alloy for materials (hereinafter referred to as the second invention).

The effects of each component and the content thereof in the present invention will be described below (the reasons for limiting them as described above).

(a) Fe, 5i By regulating Fe to 0.20% or less and Si to 0.10% or less, the thermal conductivity of Ag is increased and the buckling resistance during brazing is significantly improved. I can do it. Fe%
By suppressing Si within this range, it is possible to increase the recrystallized grain size of the core material immediately before brazing in the brazing sheet fin material, reducing the diffusion of Si in the brazing material to the core material grain boundaries, and improving the fin material. It is possible to improve the buckling resistance of.

If the content of Fe and Si exceeds the above range, thermal conductivity and buckling resistance will deteriorate.

(b) Zr0.01 in Ag with the amounts of Zr, Cr Fe, and Si regulated within the above ranges.
An alloy to which Cr 0.01=0.3% is added alone or in combination has further improved buckling resistance while maintaining thermal conductivity. This addition amount is 0.01
If it is less than 0.3%, the buckling resistance will not be improved sufficiently, and if it exceeds 0.3%, large intermetallic compounds will crystallize, leading to a decrease in plastic workability and thermal conductivity.

In the present invention, unavoidable impurities such as Cu, Ti, Mn, etc. are equivalent to Afl base metal of 142% or more (Cu 0.99%).
0.02% or less, and Ti and Mn are each 0.03% or less), there is no problem.

The fin material using the Afl for fin material and the Ag alloy of the present invention is used as a semi-rigid plate in the form of a plating sheet or a plate in which both sides of the core material are coated with a brazing material. Thickness is usually 0.1-0.2mm, width about 20-10mm
The range is 01.

In the present invention, the An of the first invention is a fin for an evaporator as shown in FIG.
mm). In addition, the Aj2 alloy of the second invention has even better buckling resistance, so it can be used not only for the evaporator fins shown in Figure 2 (a), but also for the condenser or radiator fins (usually , fin width 20 to 40n+m).

Evaluation of the heat conduction properties of the fin material can be performed as follows. AI2 and Aβ for heat exchanger fin materials of the present invention
The thermal conductivity properties of the alloy were tested and evaluated according to this method.

(1) Since the thermal conductivity of a material is proportional to its electrical conductivity, thermal conductivity characteristics can be predicted by measuring electrical conductivity.

(2) Actually form fins from thin plates for fin material, assemble them into a heat exchanger, and measure the heat exchange coefficient (cooling capacity) to confirm its effectiveness.

There are no particular restrictions on the method of manufacturing the Aρ and 19 alloy plates of the present invention, and they can be manufactured by any conventional method. First, an ingot containing each component is made, and the Al1 obtained in this way is
The Aρ alloy ingot is soaked, hot-rolled, then cold-rolled, intermediately annealed if necessary, and finally made into a semi-hard thin plate for use.

Next, the present invention will be explained in more detail based on examples.

Example 1 Aβ and A of the compositions shown in Table 1 were prepared by a conventional dissolution method.
l1. The alloy was melted and water-cooled to form an ingot. Although not shown in the same table, these A℃ and An alloys all contain CuO902% or less and Ti0.0% as unavoidable impurities.
3% or less, Mn 0.03% or less (conventional alloy only 1.1%
).

Next, this ingot was subjected to soaking treatment at a temperature of 550°C for 3 hours, and then both sides were face-sided.
1-9% Si alloy) plates were combined, heated again to a temperature of 500°C and hot-rolled to obtain a laminated plate with a thickness of 5 mm.

This was cold rolled to a thickness of 0.2 am, and then intermediate annealed (
360° C. for 2 hours) and cold rolled to a thickness of 0.16 mm (cladding ratio of brazing metal: 10% on one side) to prepare a sample of a laminated fin material.

Regarding this sample, the electrical conductivity and amount of droop (buckling resistance) after brazing heat (610° C. x 3 minutes) were measured. The results are shown in Table 2.

Note that the electrical conductivity is a value when compared with the electrical conductivity of pure copper as 100. To measure the amount of droop, cut out a sample with a width of 22 mm and a length of 50 mm, and cut one end of the sample by 30 mm as shown in Figure 3.
The other end was fixed to a jig so as to protrude, and the amount of drooping of the tip after heating was measured. 012aI if the amount of droop (h) is 2■ or less
A value exceeding II+ and 5 mm or less was indicated by ○, and a value exceeding 5 mm was indicated by an X.

A prototype fin material (pressure: 0.16 a+m, semi-rigid board) consisting of only a bare core material without a brazing material 4045 plate was made, and the amount of conductivity droop was measured in the same manner as above. The results are shown in Table 3.

Table 1 Table 2 Table 3 Example 2 AI2 and An alloy thin plate samples for fin materials prepared in Example 1 (No. 1 to 7 (invention alloy) and No.

13 (conventional alloy)) was used to prototype an evaporator with corrugated fins shown in Figure 2 (a) (fin width 100 mm; tube is an extruded 20-hole tube, 1
050 pure Ag, outer peripheral wall thickness (1.8 mm; inert gas brazing using fluoride flux).

Regarding this core, the cooling capacity, the buckling resistance of the fins, and the maximum pitting depth of the tube in a corrosion test were measured. Regarding the cooling capacity test, fin material sample No. 1.3, 5
．． 7 and 13.

The test method and judgment method are as follows.

(1) Cooling capacity test JIS D 1618 (automobile air conditioner test method)
I followed the instructions.

(2) Fin buckling resistance When brazing, it is assumed that there is no brazing failure between the fin and the extruded tube due to fin buckling, and the distance between the bent tubes (β: 22 mm before brazing) is set before and after brazing. A reduction of 0.3 mm or less was considered to be a buckling-resistant housing.

(3) Corrosion test The core was filled with N2 gas at a pressure of 15 kg/crrr, and a CASS test was conducted for 720 hours (1 month), and the time until pressure leakage was compared. If there was no pressure leak, the maximum pitting depth that occurred in the tube was measured and compared.

The results are shown in Table 4.

Example 3 61 alloy thin plate sample No. for fin material created in Example 1
, 4 to 7.13 was used to prototype the capacitor shown in FIG. 2 (b) (fin width: 22 mm).

The tube is extruded 4-hole, pure aluminum 1050, outer wall thickness 0.8 mm, inert gas brazing using fluoride slacks). This core was tested for cooling capacity and fin buckling resistance in the same manner as in Example 2.

For the cooling capacity test, fin material sample No.

4.6.13. The results are shown in Table 5.

Table 5 As described above, according to the present invention (first invention), it is possible to obtain a fin material that does not suffer from settling or deformation during soldering of the fin and has improved thermal conductivity and buckling resistance. Therefore, not only the heat dissipation characteristics of the heat exchanger are improved, but also the size and weight of the heat exchanger can be reduced.

Furthermore, according to the present invention (second invention), it is possible to provide a fin material with even better buckling resistance. Therefore, it is possible to reduce the thickness of the fin material of the layer 1, and it is possible to manufacture a small and lightweight f-exchanger with excellent heat dissipation characteristics.

[Brief explanation of the drawing]

Figure 1 is a side sectional view showing an example of a plating sheet for fins, Figures 2 (a), (b), and (c) each show an example of an Aβ heat exchanger, and (a) shows an evaporator.
(B) is an explanatory diagram showing a condenser (C) is a radiator. FIG. 3 is an explanatory diagram showing an example of a buckling resistance testing device. 1... Fin material 2... Brazing material 3... Tube 4... Corrugated fin 5... Jig 6... Sample diagram Figure 3 Figure 2 (A) (C)

Claims (2)

[Claims] (1) Al for heat exchanger fin material by brazing, characterized in that Fe is 0.2 wt% or less, Si is 0.1 wt% or less, and the balance is Al and unavoidable impurities. (2) Fe 0.2 wt% or less, Si 0.1 wt% or less, Zr 0.01 to 0.3 wt%, Cr 0.01 to 0.3
An Al alloy for heat exchanger fin material formed by brazing and bonding, characterized in that it contains one or two of these wt%, and the remainder consists of Al and unavoidable impurities.