JPS5928547A - Copper alloy for radiator fin of automobile - Google Patents

Abstract

PURPOSE:To increase corrosion resistance and attain light weight and durability for a long life without deteriorating thermal conductivity and heat resistance by composing a copper alloy of specified rate of Zn, Cr, Zr and Cu. CONSTITUTION:A copper alloy for radiator fin of automobile composed of 0.1- 2wt% Zn, 0.01-0.2wt% Cr or 0.01-0.3wt% Zr and remainder Cu is provided. This alloy does not appreciably decrease its thermal conductivity and heat resistance and has excellent corrosion resistance even if it is in corrosive environment where chlorine and sulfur are mixed together. Therefore, the radiator increases its life and is modified to light weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper alloy for fins of automobile radiators, and is an attempt to improve corrosion resistance without significantly reducing the heat dissipation properties of conventional alloys.

An automobile radiator is used to prevent the temperature of the engine from rising.It circulates water, which is a cooling medium, between the engine and the radiator, and cools the engine by dissipating the heat of the water that has risen in temperature in the engine. is being carried out.

A radiator usually consists of a tube through which water passes and fins that transfer heat from the tube and dissipate the heat into the atmosphere.
This is then forced to blow air to promote heat dissipation. Conventionally, the fins of such a C radiator (:u K
A copper alloy thin plate with a thickness of 0.0:3 to 0.2 mm containing wt% is used.

However, recently, the driving environment for automobiles has deteriorated significantly as chlorine, nitrogen oxides, sulfur dioxide gas, etc. have increased in the air, and chlorine compounds, which are antifreeze agents, are being sprayed on roads. Corrosion of radiators installed in automobiles is accelerating year by year.

Radiators are usually installed at the front of the car to improve heat dissipation, and the contaminated air is forcibly blown onto them.They also come into contact with corrosive media due to anti-freezing agents jumping up from the road, so they are under severe conditions for corrosion. It is placed below. On the other hand, when the radiator fins corrode, heat dissipation performance deteriorates.
As corrosion progresses further, it falls off from the tube, significantly reducing heat dissipation.

In recent years, automobiles have been required to be 1-digit (in order to save energy and reduce exhaust gas), and radiators, which are some parts of automobiles, are no exception, and the fins that are their constituent parts are also required to be thinner and lighter. Therefore, in addition to improving the heat dissipation per unit area of fins, maintaining their service life is an important issue.

Under this situation, the current fin materials are Cu, K, and Cd.

A material to which 0.1 to +wt% of one or both of Sn is added has almost no resistance to corrosion (improvement of this is desired).

In view of this, as a result of detailed observation of the corrosion state of the fin, the present invention found that corrosion is caused by the formation of multiple layers of cuprous oxide, an oxide, on the metal surface of the fin, and the presence of chlorine and sulfur at the interface between the cuprous oxide and the metal. As a result of research on corrosion-resistant materials under these conditions, we developed a fin material with excellent corrosion resistance. So 7, n O, 1~
2. Q wt% and CrO, 01-0.2 wt%,
The present invention relates to a copper alloy for a fin of an automobile radiator, which contains any one of ZrO201 to Q and 3 wt%, and the remainder is copper.

That is, in the present invention, by adding a small amount of Zn to Cu,
Chlorine, without significantly reducing the unique thermal conductivity of u.
Improves corrosion resistance in air containing nitrogen oxides, sulfur dioxide gas, etc.
By adding a small amount of seeds, the corrosion resistance is further improved due to the mutual effect with the addition of Zn, and the heat resistance is also enhanced.

However, in the alloy of the present invention, the Zn content is 0.1 to 2w.
The reason why it is limited to t% is that if it is less than 1wt%, the effect of improving corrosion resistance will be small, and if it exceeds 2wt%, the thermal conductivity, which is important as a fin material, will be significantly reduced.

The reason why the content of Cr and Zr is limited as above is that if the content of both is less than 0.01wt%, the effect of corrosion resistance and the improvement of heat resistance will be small.
If the Zn content exceeds 0.3 wt %, the effect of improving corrosion resistance and heat resistance will be large, or the thermal conductivity, which is important for fin materials, will be drastically reduced, making it undesirable as a fin material. be.

The alloy of the present invention will be explained below with reference to examples.

Copper was melted using a graphite crucible, the surface of the melt was coated with charcoal powder, and additional elements were inserted, after which it was cast into a mold to a thickness of 25 mm and a width of 250 mm with the composition shown in Table 1.
An ingot with a length of 250 mm was obtained. Next, this ingot was ground by 2.5 mm per surface, hot rolled according to a conventional method, and then intermediate annealing and cold rolling were repeated until the thickness was 0.5 mm.
(Final processing rate -40%).

A sample for corrosion test, a sample for thermal conductivity, and a sample for heat resistance test were taken from this plate, and the corrosion resistance, thermal conductivity, and heat resistance were tested and evaluated. The results are also listed in Table 1.

The corrosion resistance was measured using a sample with a plate thickness of 0.5 mm, length 10 (1 mm, width 100*m), and 0.3% SQ2 gas and 0.3% SQ2 gas.
It was exposed to air containing 3% Cd gas for 48 hours, then heated, weighed, and the maximum corrosion reduction was calculated from the weight before and after the test.
The value per unit area was calculated.

Regarding thermal conductivity, we measured electrical conductivity, which has a strong positive correlation with thermal conductivity.

In addition, as for the heat resistance test, it is clear from Table 1 that the alloy of the present invention is 350"C, and the alloy of the present invention is \+11 ~] 3.
It can be seen that the thermal conductivity and heat resistance are almost the same, and the corrosion resistance is significantly improved compared to the conventional alloy Nλ24 (c).

On the other hand, from the composition range of the alloy of the present invention, Z1] content,
Comparative alloy L with either lower Cr content or lower Zr content
Although 14.15.19.20 has good thermal conductivity, there is almost no improvement in corrosion resistance. Comparative alloy Arashi 16°17, 18.21.2, 2 in which one or two of Z11 content, Cr content, and Zr content σ are higher than the composition range of the present invention alloy.
No. 23 has good corrosion resistance and heat resistance, but the thermal conductivity is significantly reduced and is not practical as a fin.

As detailed above, the alloy of the present invention has excellent corrosion resistance in a corrosive environment for fin materials containing chlorine and sulfur, and also has sufficient heat resistance and thermal conductivity, making it possible to reduce the weight of automobile radiator fins and extend their service life. It has a remarkable effect on

Procedural Amendment (Method) To the Commissioner of the Patent Office December 1980/l E3 Kuki 1 Indication of the case Japanese Patent Application No. 136615/1982 2 Title of the invention Copper alloy for fins of automobile radiators
Representative of the person making the amendment Funahashi Katsu 5 Daily edition of the amendment order November 30, 1980 & Target of amendment Column for detailed explanation of the invention in the specification (no change in content) Constant temperature and humidity at 60 degrees Celsius and humidity 5 OLIJ Holding in the tank for 96 hours was repeated four times, the corrosion products were removed, the weight was measured, and the corrosion weight loss was determined from the weight before and after the test, and the value per unit area was calculated.

Regarding thermal conductivity, we measured electrical conductivity, which has a strong positive correlation with thermal conductivity.

As for the heat resistance test, the sample was immersed in a salt bath at 550°C for 10 minutes, then taken out and left to cool, and the hardness of the cross section of the sample was measured, and those with high hardness were judged to have good heat resistance.

Table 1

Claims (1)

[Claims] Zn O, 1~2.0 wt q6 and Cr O, 01~
0.2 wt %, Zr 0.01 to Q, 3 wt %, and the remainder copper.