JPH0987780A - Beryllium copper alloy for heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a beryllium copper alloy for heat exchanger excellent in corrosion resistance and contamination resistance to seawater, furthermore, high in heat conduction and moreover, capable of easily producing a large heat exchanger. SOLUTION: This beryllium copper alloy for heat exchanger is the one having a compsn. contg. 1.0 to 2.5% beryllium, in which the total content of nickel and cobalt is regulated to 0.2 to 0.6%, and the balance copper with inevitable impurities, and in which the heat conduction is regulated to >=0.25cal/cm.sec. deg.C. The above beryllium copper alloy for heat exchanger can be obtd. by executing bulk overaging in which the final heat treating temp. is regulated to 450 to 600 deg.C and the final heat treating time to 3 to 24hr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beryllium copper alloy for heat exchangers, and more particularly to a beryllium copper alloy for heat exchangers suitable for heat exchangers using seawater as a cooling source or a heat source.

[0002]

BACKGROUND OF THE INVENTION Beryllium copper alloys have relatively good thermal conductivity, and also have excellent corrosion resistance and antifouling properties against seawater, and are therefore useful as materials for heat exchangers that use seawater as a cooling source or a heat source. is there. However, in order to withstand the severe corrosive environment of seawater, the beryllium content is set to 1.
It must be 0% or more, and it was not possible to obtain a thermal conductivity of 0.2 cal / cm.sec.sec. Therefore, the conventional beryllium copper alloy has a problem in that it cannot be said to be sufficient in terms of heat transfer.

Further, when a heat exchanger is manufactured from a beryllium copper alloy, a pipe is manufactured in the process of hot extrusion → cold drawing → solution treatment → finish drawing → hardening treatment in a multi-tube heat exchanger, For plate heat exchangers, plates are manufactured by the steps of hot rolling → cold rolling → solution heat treatment → finish rolling → hardening treatment, but the process is long and requires a large solution heat treatment furnace. , Was financially difficult. Therefore, it has been extremely difficult to manufacture a particularly large heat exchanger.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and is excellent in corrosion resistance and antifouling property against seawater, has a large thermal conductivity, and can easily form a large heat exchanger. The purpose is to provide a beryllium copper alloy for a heat exchanger that can be manufactured.

[0005]

The beryllium copper alloy for a heat exchanger of the present invention made to solve the above-mentioned problems is
Beryllium content is 1.0 to 2.5% (wt%), sum of nickel and cobalt contents is 0.2 to 0.6%, the balance is copper and inevitable impurities, and thermal conductivity is 0.25 cal / cm · se.
It is characterized in that the temperature is above c- ° C. In addition,
This beryllium copper alloy for heat exchanger has a final heat treatment temperature.
It is preferable that the final heat treatment time is 450 to 600 ° C. and the time is 3 to 24 hours.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The beryllium-copper alloy for a heat exchanger of the present invention has a beryllium content of 1.0 to 2.5%, a sum of nickel and cobalt contents of 0.2 to 0.6%, and the balance being copper and inevitable impurities. Has been done. If the beryllium content is less than 1.0%, it cannot withstand the severe corrosive environment of seawater as described above. On the other hand, if the beryllium content exceeds 2.5%, crystallization of the γ phase is unavoidable, workability is deteriorated, and thermal conductivity is deteriorated. If the total content of nickel and cobalt is less than 0.2%, the crystal cannot be made finer and the workability will be deteriorated. On the contrary, if it exceeds 0.6%, the economic efficiency will be impaired and the spreadability will be impaired. Therefore, it is not preferable.

The beryllium copper alloy for heat exchanger of the present invention comprises
It can be obtained by performing bulk overaging instead of the conventional solution heat treatment->finishing-> hardening treatment. In this bulk overaging, in the case of a drawn material, it is only necessary to cut it to a fixed length, and in the case of a rolled material, it is sufficient to heat it in a furnace while winding it in a coil shape, and there is no need for water cooling. In the case of the multi-tube type, the process is hot extrusion → cold drawing → bulk overaging, and in the case of the plate type, hot rolling → cold rolling → bulk overaging.

The final heat treatment temperature for this bulk over-aging is 450 to 600 ° C., and the final heat treatment time is 3 to 24.
It is time. If the final heat treatment temperature is less than 450 ° C or the final heat treatment time is less than 3 hours, sufficient workability cannot be obtained and a thermal conductivity of 0.25 cal / cm · sec · ° C or more can be obtained. Can not. Conversely, the final heat treatment temperature is 60
It is economically unfavorable that the temperature exceeds 0 ° C or the final heat treatment time exceeds 24 hours. As described above, the beryllium copper alloy for heat exchanger of the present invention is obtained by subjecting the alloy having the above composition to bulk overaging at a final heat treatment temperature of 450 to 600 ° C. for a final heat treatment time of 3 to 24 hours.
It achieves a thermal conductivity of sec. ℃ or more, which is 0.2cal / cm which is the thermal conductivity of beryllium copper alloy that has been subjected to normal heat treatment, which is much higher than that of conventional beryllium copper alloy. High thermal conductivity not found in alloys.

As described above, in the beryllium copper alloy for heat exchangers of the present invention, the steps of solution heat treatment → finishing → hardening treatment are replaced by bulk overaging. It is possible to shorten the number of steps and eliminate the need for an expensive solution treatment furnace.

[0010]

Example 1 A beryllium copper alloy having a beryllium content of 1.90%, a sum of nickel and cobalt contents of 0.30%, and a balance of copper and unavoidable impurities was hot-rolled under appropriate conditions. After cold rolling under various conditions, the final heat treatment temperature was 500 ° C. and the final heat treatment time was 10 hours for bulk overaging to manufacture a heat transfer plate for a plate heat exchanger. The thermal conductivity of this material was 0.3 cal / cm · sec · ° C. Compared with this, conventional beryllium copper alloy (beryllium content 1.90%, sum of nickel and cobalt content 0.30%, solution heat treatment condition 800 ℃ × 2 hours, hardening treatment condition 280 ℃ × 4
The heat conductivity of the heat transfer plate is 0.2 cal / cm
sec · ° C., and it was confirmed that the beryllium copper alloy for heat exchangers of the present invention has a very high thermal conductivity.

The heat transfer plates of the present invention material and the conventional material obtained as described above were brought into contact with seawater at a flow rate of 1 m / min, and the corrosion depth for one year was measured.
It was found that the material of the present invention has the same corrosion resistance and antifouling property against seawater as the conventional material. Further, as a result of immersing the test plate in seawater for 1 year and examining the antifouling property against shellfish and algae, the results are as shown in Table 1 below.

[0012]

[Table 1]

Example 2 Next, four kinds of beryllium copper alloys for heat exchangers shown in Table 2 were manufactured, and the final heat treatment temperature and the final heat treatment time were variously changed to obtain the thermal conductivity of the obtained material. It was measured. The results are shown in Tables 3 to 6.

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

[0017]

[Table 5]

[0018]

[Table 6]

[0019]

As described above, the beryllium copper alloy for a heat exchanger of the present invention has a large thermal conductivity which has not been found in the prior art by changing the alloy composition and heat treatment conditions. Therefore, if it is used as a heat transfer member of a heat exchanger, an excellent heat transfer effect can be obtained. Further, the beryllium copper alloy for heat exchangers of the present invention does not require a solution treatment step as in the conventional art, and therefore, the manufacturing process of the heat exchanger can be shortened, and since a solution treatment furnace is not required, a large heat treatment is not required. There is also an advantage that pipes and plates for exchangers can be manufactured easily and economically.

Front Page Continuation (72) Inventor Mitsuto Mitsui Nihon Insulator Co., Ltd. 2-56 Sudacho, Mizuho-ku, Nagoya-shi, Aichi (72) Inventor Toshio Yoshioka 2-56, Suda-cho, Mizuho-ku, Nagoya, Aichi Nihon Insulator Co., Ltd.

Claims (2)

[Claims] 1. A beryllium content rate of 1.0 to 2.5%, a sum of nickel and cobalt content rates of 0.2 to 0.6%, the balance being copper and inevitable impurities, and a thermal conductivity of 0.25 cal / cm.
-Sec-Beryllium-copper alloy for heat exchangers characterized by having a temperature of ℃ or more. 2. The beryllium copper alloy for a heat exchanger according to claim 1, wherein the final heat treatment temperature is 450 to 600 ° C. and the final heat treatment time is 3 to 24 hours.