JPH0674468B2 - Copper alloy for automobile radiator fins - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a copper alloy for fins of a radiator for an automobile, and in particular, it improves the corrosion resistance of the fins without degrading the heat radiation characteristics of the radiator.

Generally, a radiator for an automobile is provided to prevent the temperature of the engine from rising.By circulating water, which is a cooling medium, between the engine and the radiator, the water whose temperature has risen in the engine is radiated by the radiator. The department is cooling. The radiator consists of a tube through which water passes and a fin that dissipates the heat from the tube into the atmosphere. It is usually attached to the front of a vehicle and forcedly blows air to promote heat dissipation.

Conventionally, fins for automobile radiators are made of Cu, Sn, Cd.
Alternatively, a copper alloy containing 0.1 to 1.0 wt% of Ag (hereinafter wt% is simply referred to as%) is used. These alloys have a certain level of strength and good heat resistance, only a 5 to 10% decrease compared to Tough Pitch copper, which has the highest heat dissipation characteristics of copper-based materials as a radiator, and when used as a radiator. It has the advantage that it does not soften due to the high temperature and soldering heating during manufacturing of the radiator.

However, recently, the amount of chlorine, nitrogen oxides, sulfurous acid gas, etc. in the air has increased, and chlorine compounds have been sprayed on the road as antifreeze agents, which significantly deteriorates the driving environment of automobiles and corrodes automobile radiators as well as automobile radiators. Is accelerating. Especially since the radiator improves the heat dissipation characteristics,
Since it is installed in the front of the car and forcedly blows polluted air, when humidity and temperature are in specific conditions, the corrosion of the radiator accelerates, which deteriorates the heat exchange characteristics of the radiator and shortens its life. There was a flaw.

The present invention, in view of this, as a result of observing the corrosion state of the fins in detail, the corrosion is a multi-layered oxide Cu ₂ O on the metal surface of the fin, chlorine and sulfur aggregated at the interface between Cu ₂ O and the metal In general, we found that the corroded surface has a very small amount of water in a dry state, and as a result of our research on corrosion resistant materials under such conditions, we found that it has a sufficient heat dissipation property and excellent corrosion resistance for automobile radiator fins. Developed a copper alloy containing Ni0.005-1.0%, Si0.005-0.5%, balance Cu
It is characterized by consisting of.

That is, the present invention, based on the above findings, various copper alloys, as a result of the simultaneous presence of sulfur and chlorine as a corrosion medium, and as a result of performing a corrosion test in an environment of low water content, Cu
By simultaneously adding Ni and Si, formation and growth of a Cu ₂ O layered coating could be prevented.

However, the reason why the alloy composition is limited as described above in the present invention is as follows.

That is, even if the Ni content is less than 0.005%, the Si content is 0.005%.
If the content is less than 1.0%, it has little effect on corrosion accompanied by Cu ₂ O proliferation, and if the Ni content exceeds 1.0%, the Si content is 0.5%.
This is because the corrosion resistance is improved even if the value exceeds the range, but the heat radiation effect as the radiator is reduced.

Hereinafter, the present invention will be described in detail with reference to Examples. After melting Cu using a graphite crucible and coating the molten metal surface with charcoal powder, insert additional elements, melt the alloy with the composition shown in Table 1, water-cool cast it to a thickness of 50 mm. , Width 150 mm, length 1
A 000 mm ingot was obtained. This ingot is hot-rolled to a thickness of 12 m
The thickness was set to m, and both sides were chamfered with a thickness of 1.5 mm, and then annealing and cold rolling were repeated to finish a plate with a thickness of 0.05 mm.

This plate was subjected to a corrosion test, fins for radiators were prepared from the plates, and by incorporating the fins into automobile radiators, heat dissipation characteristics were measured. The results are also shown in Table 2.

For the corrosion test, a sample with a width of 30 mm and a length of 100 mm was cut out from a plate with a thickness of 0.05 mm, exposed to air containing 0.3% SO ₂ and 0.3% Cl ₂ gas for 48 hours, then at a temperature of 60 ° C and humidity. Retaining in an 80% constant temperature and humidity chamber for 96 hours is repeated 5 times, and a strip type test piece with a width of 15 mm and a length of 100 mm is made from this, and the tensile strength is measured and the strength deterioration rate is calculated from the following formula. Was evaluated for corrosion resistance.

The heat dissipation characteristics of the manufactured automobile radiator are 10 l.
The water in the tank was heated to a temperature of 90 ° C and then circulated through a radiator, and the time until the water temperature at the radiator outlet reached 60 ° C was measured.

This is shown as 100 in the case of the conventional alloy (Cu-0.15% Sn).

An air blower fan was provided in front of the radiator to forcibly cool it.

As is clear from Table 1, all the fins made of the alloy of the present invention exhibit excellent corrosion resistance and good heat dissipation characteristics.

On the other hand, Ni or Si content is less than the composition range of the alloy of the present invention Comparative alloys No. 7, No. 9 corrosion resistance is not improved, Ni or Si content is more than the composition range of the alloy of the present invention It can be seen that the heat dissipation characteristics of the comparative alloys No. 8 and No. 10 are inferior.

As described above, the alloy of the present invention has excellent corrosion resistance and sufficient heat dissipation as a fin for an automobile radiator, and has a remarkable effect of extending the life of the radiator.

Claims (1)

[Claims] 1. A copper alloy for a fin of an automobile radiator, containing 0.005 to 1.0 wt% of Ni and 0.005 to 0.5% of Si, and the balance Cu.