JPS61113739A - Copper alloy having superior corrosion resistance - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy having superior corrosion resistance as well as superior heat resistance and heat conductivity by providing a specified composition consisting of S and Cu. CONSTITUTION:This Cu alloy having superior corrosion resistance consists of 0.01-1.0wt% S and the balance Cu with inevitable impurities and has superior heat resistance and heat conductivity. The alloy is suitable for use as a material for a heat exchanger, especially as a material for the fins of a radiator for an automobile. In case of <0.01% S, it is not effective in improving the corrosion and heat resistances. In case of >1.0% S, it does not further improve the corrosion resistance, causes a problem on manufacture such as hot brittleness and reduces the heat conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper alloy with excellent corrosion resistance, and is intended to reduce the thickness and extend the life of heat exchangers, particularly radiator fins for automobiles.

The fins of an automobile radiator are connected to the radiator tube and have the function of dissipating the heat of the cooling medium flowing inside the tube into the atmosphere. Therefore, the characteristics required for fins are:

Tinned copper has conventionally been used as a material that satisfies these required properties in terms of heat resistance and thermal conductivity.

However, in recent years, the fins of automobile radiators have been severely corroded due to deterioration of environmental conditions due to the increase in SO and gas, exhaust gases, coastal atmosphere containing seawater, and even snow melting agents sprayed during snowfall, which has seriously affected the heat dissipation performance and lifespan of the radiator. Problems such as severe damage to the vehicle have attracted attention. Furthermore, as automobiles tend to be lighter in recent years, fins tend to become thinner, and even slight corrosion can lead to deterioration in radiator performance.

Under these circumstances, the current fin material, cast copper thin plate, has low resistance to corrosion.

Furthermore, there was a desire to develop a copper alloy with excellent corrosion resistance.

The present invention is the result of research conducted in view of these points.

We have developed a copper alloy with excellent corrosion resistance for heat exchangers, especially for automobile radiator fins.

In the present invention, S is α01 to 1. The present invention relates to a copper alloy having excellent corrosion resistance, containing Owt% of the balance Cu and unavoidable impurities.

The S content was set to CL01 to 1. The reason for setting it as Owt% is.

When the S content is less than α01 wt%, no improvement in corrosion resistance and heat resistance is observed, and when the S content is less than 1.0 yt
If it exceeds 4, the effect of improving corrosion resistance is saturated and manufacturing problems such as hot embrittlement occur.

This is also because thermal conductivity decreases.

EXAMPLES Alloys having the compositions shown in Table 1 were melted, hot-rolled, annealed as appropriate, and then cold-rolled into plates with a thickness of L4M. As a result of research, atmospheric corrosion of radiator fins is
Since temperature, humidity, and salinity were found to be important factors, the following test method was used to evaluate the corrosion resistance of the sample materials. That is, the specimens were exposed to an atmosphere of 70° C. and a relative humidity of 901, sprayed with artificial seawater shown in Table 2 as appropriate during the test, and after 15 days, they were pickled and the weight loss before and after the test was determined.

This weight loss was converted to 1 diI day and was defined as the corrosion rate.

Heat resistance was determined by holding a cold-rolled material with a final working degree of 50- for 30 minutes at each temperature, and its hardness was 80% of the hardness of the cold-rolled material.
The temperature at - was evaluated as the softening temperature.

Thermal conductivity was evaluated based on electrical conductivity, which is correlated with thermal conductivity.

The results are shown in Table 1, and according to this, S is 0, 01 to 1
．． It can be seen that the alloys of the present invention (I & 1 to 6) containing Owt$ have superior corrosion resistance compared to the conventional alloy (47).

As described above, the alloy of the present invention has excellent corrosion resistance, heat resistance, and thermal conductivity, and has excellent balanced properties suitable for use in heat exchangers, especially as an automobile radiator fin material. It is an alloy.

Table 1

Claims (1)

[Claims] A copper alloy with excellent corrosion resistance, containing 0.01 to 1.0 wt% of S, the balance being Cu and unavoidable impurities.