JPS5856016B2 - Method for manufacturing aluminum alloy extruded shapes for fluid passage materials in heat exchangers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum alloy extruded shape for heat exchangers and a method for manufacturing the same, and more specifically, it has excellent corrosion resistance as a heat exchanger, and has improved extrudability and bending workability. The present invention relates to fluid passage materials for aluminum heat exchangers.

In recent years, the use of aluminum heat exchangers in transportation equipment and industrial equipment has expanded significantly.

These are often manufactured by brazing, and a plating sheet clad with an Al-8i brazing alloy is used as a part of the member.

For example, in a car air conditioner for an automobile, the working fluid (e.g. Freon gas) passage material is pure aluminum pipe material (including shapes), and the cooling fins on the air side are made of Al-Mn, A.
l-Mg-8i alloy as core material, Al-8i) Al
A plating sheet whose skin material is a Si-Mg alloy is used.

However, when such a heat exchanger is used in a severely corrosive environment, pitting corrosion may occur from the outside (air side) of the fluid passage material, resulting in leakage of the working fluid.

To explain this using drawings, in FIG. 1, 1 is a fluid passage member, 2 is a fin, and both are fillet portions 3
However, with conventional constituent materials, the potential of the fillet portion 3 becomes noble, the fluid passage material 1 side becomes an anode, a corrosion current flows as shown by the arrow, and pitting corrosion 4 occurs in the fluid passage material 2. Occur.

As a method for preventing such pitting corrosion, it has been considered to use an aluminum alloy (for example, Al-Zn1AlSn system) having a base potential for the fins, and to prevent the fluid passage material from corroding by its sacrificial anode action.

For example, the A3003 alloy has excellent corrosion resistance as a heat exchanger unit, but it has poor extrudability, resulting in high material costs and poor bending workability, resulting in poor product precision.

The present invention aims to provide an aluminum alloy extruded shape for a heat exchanger that further enhances the anticorrosion effect, has good extrudability and bending workability, is inexpensive, and has good product precision.

That is, in the present invention, M n 0.30 to 0.7%, C
Contains u0.07-0.20% and 0.06% or less Ti and 0.05% or less B in total of 0.01-0.06%, further Fe≦0.60%, Si≦0 .30%, M
g≦0.05%, Cr≦0.05%, Zn≦0.20%
However, Fe is always larger than Si, and the remaining Al
This is an aluminum alloy extruded shape for a fluid passage material of a heat exchanger, characterized by comprising the following.

The present invention also provides an alloy material having the above composition at a temperature of 500 to 620'C.
This is a method for manufacturing an aluminum alloy extruded shape for a heat exchanger, which is characterized in that the aluminum alloy extruded shape for a heat exchanger is manufactured by soaking for 3 hours or more and then extruding.

In the alloy composition according to the present invention, Mn enhances the potential of the fluid passage material in the heat exchanger and increases the relative potential difference with the anti-corrosion fin material, making it useful for preventing corrosion of the fluid passage material. If it is less than .30%, there is no effect, and if it exceeds 0.7%, the extrudability and bending workability deteriorate, which is not preferable.

Like Mn, Cu is responsible for the potential as a fluid passage material and is useful for its corrosion prevention.If it is less than 0.07%, it has no effect, and if it exceeds 0.20%, the extrudability decreases and the fluid passage material is Self-corrosion of the material increases.

Ti and B serve to refine the structure of the ingot and improve its extrudability and bendability.

If the total amount of both Ti and B is less than 0.01%, the above effect will not be obtained, and if the total amount of both exceeds 0.06%, a compound will be formed during casting, causing material defects.

F eXS t N Mgs CrlZ When n exceeds the upper limit, extrudability is inhibited.

In particular, Cr also inhibits bending workability, and Zn makes the potential less noble and deteriorates the corrosion resistance of the fluid passage material.

In addition, in the manufacturing method, soaking at 500 to 620°C for 3 hours or more causes the eutectic composition to infiltrate, and Mn appropriately aggregates and precipitates in the matrix, improving extrudability and improving re-extrudability. It is effective in preventing coarsening of crystal grains.

If this temperature is less than 500'C, extrudability deteriorates significantly, and
Mn precipitates too finely, leading to coarsening of crystal grains.

If it exceeds 620'C, there is a risk of melting and it is inappropriate.

Next, Examples and Comparative Examples of the present invention will be explained, and the test results will be described.

First, the chemical composition of the alloy material is shown in Table 1.

The alloy ingots of Arashi 1 to Arashi 20 in Table 1 above were heated to 550°C.
The product was soaked for 8 hours at 5000C, extruded into a porous tube with 25 holes, and bent into a serpentine tube shape.

The test results for extrudability and bending workability are shown in Table 2.

The above extruded section is used as a working fluid passage, and the fin material is made of AI-1,2%Mn-0,05%Sn alloy as the core material and A7-10%5i-1,5%Mg as the skin. An evaporator for a car air conditioner was made by vacuum brazing a plating sheet at 10'' Torr at 600°C for 3 minutes.

Table 3 shows the potential of this working fluid passage in a 3% NaClj (pH=3) aqueous solution (v: saturated calomel electrode reference) and the results of the corrosion test.

Corrosion test was conducted using 3% NaCl (pH=3) aqueous solution at 400C.
A dry-wet alternating test was conducted in which 4% NaCl (pH = 3) and 0.5% NaCl (pH = 3) were immersed in water for 30 minutes and dried at 50°C for 30 minutes for 1 month.
26&/1CuCA! A CASS test was conducted in which a solution of No. 2 was sprayed at 40° C. for one month.

Next, the alloys of Arashi 1 to 7 were soaked at 480°C for 8 hours, and a porous tube having 25 holes was extruded at 500°C and bent into a serpentine tube shape.

The results are shown in Table 4.

As is clear from the above test results, the profile of the present invention not only has good corrosion resistance but also excellent extrudability and bending workability.

On the other hand, if the composition of each component is out of the range and the soaking temperature is low, the intended purpose cannot be achieved.

The shape material according to the present invention is suitable for car air conditioner evaporators, condensers, oil coolers, etc., but application examples other than those mentioned above are as follows.

Application example 1 Alloy ingots of Arashi 1 to 7 were soaked at 600℃ for 4 hours,
It was extruded at 520° C. into a porous tube with 3 holes and bent into a serpentine tube shape.

On the other hand, the fin material has A70.6%M g -0.4%5
i-0.2% Cu alloy as core material, l? - Using a plating sheet made of 12% Si as a skin material,
An oil cooler was produced by flux brazing at 90° C. for 5 minutes.

Application Example 2 Alloy ingots of Ganes 1 to 7 were soaked at 520°C for 15 hours, extruded at 500°C into a porous tube having 4 holes, and bent into a serpentine tube shape.

On the other hand, the fin material contains Al-0.8%Mn-1%Zn.
Using alloy as core material, kl-10%5i-0,01%B i
- Using a plating sheet made of 0,005% Be, connect the porous tube to the N2 gas atmosphere (dew point: 65°C).
Hereinafter, a condenser for a car air conditioner was manufactured by performing brazing in an inert gas atmosphere for 6,000,012 minutes at an oxygen concentration of 5 or less.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the corrosion state of a conventional heat exchanger. 1... Fluid passage material, 2... Fin, let portion, 4... Pitting corrosion. 3...Fui

Claims (1)

[Claims] I Mn 0.30-0.7%, Cu O, 07-0
．． Contains 0.01 to 0.06% in total of 20% and 0.06% or less of Ti and 0.05% or less of B, and further contains F.
e≦0.60%, SiS2.30%, Mg≦0.05%
, Cr2O, 05%, and Zn≦0.20%, with the exception that Fe is always greater than Si, and the remainder is Al. 2 Mn 0.30-0.7%, CuO, 07-0
．． Contains 0.01 to 0.06% in total of 20% and 0.06% or less Ti and 0.05% or less B, and roughly F
e≦0.60%, SiS2.30%, Mg≦0.05%
, Cr2O, 05%, Zn≦0.20% is allowed, however, Fe is always greater than Si, and the remaining 1' is 5%.
A method for producing an aluminum alloy extruded shape for a fluid passage material of a heat exchanger, which comprises soaking at 00 to 620°C for 3 hours or more and then extruding it.