JPS60165334A - Copper alloy for fin of heat exchanger of automobile - Google Patents

Abstract

PURPOSE:To provide the titled copper alloy excellent in heat conductivity and corrosion resistance, having good processability and making it possible to prolong the life of a heat exchanger and to reduce the wt. thereof, obtained by adding a specific amount of Y and In, Ni, Fe, Co or Cr to Cu. CONSTITUTION:A copper alloy for the fin of the heat exchanger of an automobile consists of 0.005-1.0wt% Y and 0.005-0.3% one ore more of In, Ni, Fe, Co or Cr and is one of which the corrosion resistance is enhanced by suppressing the formation and growth of Cu2O in air having chlorine, nitrogen oxide and sulfur dioxide gas mixed therein by adding a small amount of Y without too much lowering the inherent heat conductivity of Cu and further enhanced by the synergistic effect with Y brought about by adding a small amount of In, Ni, Fe, Co or Cr alone or in a combination.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper alloy for fins of automobile radiators and heaters, and in particular improves the corrosion resistance of the fins without deteriorating the heat dissipation characteristics of the radiator.

An automobile radiator is a device that prevents the temperature of the engine from rising. By circulating water, which is a cooling medium, between the engine and the radiator, and dissipating the water that has risen in temperature in the engine, the radiator cools the engine. cooling the area.

Generally, a radiator consists of a tube through which water passes and fins that dissipate heat from the tube into the atmosphere, and is usually located at the front of a car, and air is forced onto it to promote heat dissipation.

Conventionally, the fins of such radiators are made of Cu and Cd.
Or a thickness of 003-0.2 mm containing 0.1-1.0'wt% (hereinafter wt% is simply abbreviated as "chi") of Sn.
However, recently, chlorine, 9 element oxides, sulfur dioxide gas, etc. have increased in the air, and chlorine compounds have been sprayed on roads as antifreeze agents, making the driving environment of automobiles significantly worse. The situation is getting worse, and the corrosion of not only automobiles but also the radiators installed in automobiles is accelerating.

In other words, since radiators are usually installed at the front of automobiles in order to improve heat dissipation, the contaminated air is blown onto them, and antifreeze can also jump up from the road and mix into the contaminated air. , which will come into direct contact with the radiator fins. Therefore, the fins of the radiator are exposed to severe corrosive conditions as they come into contact with the corrosive substances, and when the fins corrode, the heat dissipation performance of the radiator deteriorates, and if the corrosion progresses further, the fins fall off the tube and the radiator becomes unusable. It disappears.

In recent years, automobiles have been required to be lighter in order to save energy and reduce exhaust gas, and radiators, which are a part of automobiles, are no exception, and fins, which are their constituent members, are also being made thinner and lighter. Therefore, it is important for fins to improve their heat dissipation per unit area and maintain their service life.

In this situation, the current fin side slope Cu
The copper alloys to which K Cd or id:sn are added have almost no resistance to corrosion, and there is a strong desire to improve the corrosion resistance.

In view of this, the present invention has made detailed observations of the corrosion state of fins, and has found that corrosion is caused by multiple layers of oxides Cu and O on the metal surface of the fin, chlorine and sulfur condensation at the interface between Cu10 and the metal, and further We found that corroded surfaces are generally dry and contain only a small amount of moisture, and as a result of repeated research on corrosion-resistant materials under such conditions, we found that they have excellent thermal conductivity, good eating properties, and good workability. A copper alloy for fins has been developed, containing YO,005-1,0% and I
n+Ni+Fe, Co.

Total of 1 or 2 or more of Or 0005~0%←
, and the remainder is Cu.

That is, the present invention improves the production of cuprous oxide in air containing chlorine, nitrogen oxides, sulfur dioxide gas, etc., without significantly reducing the thermal conductivity peculiar to O by adding a small amount of Y to Cu. It suppresses proliferation and improves corrosion resistance, and also In, Ni, Fe, and Cjo.

By adding a small amount of one or more types of Or, it becomes possible to further improve the corrosion resistance due to the phase opening effect with Y.

The reason why the alloy composition of the present invention is limited as described above is as follows.

The reason for limiting the Y content to 0.005-10% is that if the Y content is less than 0.005-4, the effect of suppressing the production and proliferation of Cu and O is insufficient, and if it exceeds 10%, the corrosion resistance will deteriorate. However, the rolling workability deteriorates and the manufacturing cost increases considerably. Still In, Ni, Fe, C:o, Or
Addition amount of one type or two or more types 0005 to 03
%, because if it is less than 0.0054, the improvement in corrosion resistance due to the phase opening effect with Y will be insufficient; if it exceeds 0.5%, the improvement in corrosion resistance due to the phase opening effect with Y will be saturated, and Do not lower the conductivity.

Further, the alloy of the present invention can be applied both to those manufactured by non-oxidizing melting in which the remaining O contains a small amount of oxygen, and to those manufactured by atmospheric melting to have a high oxygen content.

The present invention will be described in detail below with reference to Examples.

Using a graphite crucible, tough pitch copper is melted in vacuum and in the air, each additive element is inserted into this, and this is cast into a mold to form a mold with a thickness of 25 cm and a width of 250 cm as shown in Table 1. Song,
Length 250. An ingot was obtained.

Each surface of this ingot was chamfered by 25 degrees per side, heated and hot rolled at a temperature of 850° C., and then cold rolled and intermediate annealing were repeated to form a plate with a thickness of 0.5 mm.

This plate was examined for corrosion resistance, thermal conductivity, and rolling workability. The results are shown in Table 2.

Corrosion resistance was measured by cutting a sample of 100 IllI++ vertically and 100 horizontally (15% sOt gas and 03%
The process of exposing the sample to air containing a1° gas for 1+8 hours and then holding it in a constant temperature and humidity chamber at a temperature of 60°C and a humidity of 80°C for 96 hours was repeated four times to remove corrosion products such as Cut and O on the sample surface. was removed, the weight was measured, and the corrosion weight loss was calculated from the weight before and after the test.

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

Regarding rolling workability, the above plate was repeatedly rolled and annealed to obtain a plate with a thickness between 0.1 and 1.0 m, which was then cut into lengths of 10 (1 m) and rolled to a thickness of 0.02. The number of rolling breaks that occurred was calculated.

Table 1 Table 2 As is clear from Tables 1 and 2, the alloys of the present invention have improved corrosion resistance without significantly lowering thermal conductivity than the conventional alloy NO2O. It can be seen that the properties are also good.

On the other hand, the comparative alloy Nα15, In, Ni, Fe +Co+Cj, which has a lower Y content than the composition range of the present alloy
Comparative alloy Nα16 with low r content did not significantly improve corrosion resistance, and In , Ni + Fe *O
Comparative alloy Nα1111.19, which has a high content of o and Or, shows a remarkable improvement in corrosion resistance, but on the other hand, a significant decrease in thermal conductivity, which is important for fins, is found to be unsuitable as a fin material. In addition, the comparative alloy Na1g, which has a high Y content, has poor workability and exhibits excellent corrosion resistance in corrosive environments containing sulfur, and has sufficient thermal conductivity as fins, making it suitable for use as fins in automobile heat exchangers. When used, it has the remarkable effect of increasing the lifespan of an automobile heat exchanger and making it possible to reduce its weight.

Claims (1)

[Claims] Y O,005-1,0wt% and In, Ni, F
e, a total of 0. of one or two or more of Cot Cr.
Copper alloy for fins of an automobile heat exchanger, characterized in that it contains 005-( ), 3 wt% and the balance is Cu.