JPS62151538A - Copper alloy for antisticking of marine life - Google Patents

Abstract

PURPOSE:To manufacture a copper alloy for antisticking of marine life excellent in corrosion resistance without deteriorating antifouling property, by incorporating specific percentage of Ni, Mn, and Pb to Cu. CONSTITUTION:The copper alloy consisting of, by weight ratio, 5-10% Ni, 1-5% Mn, 1-10% Pb, and the balance Cu with trace amounts of impurities is prepared. This alloy combines excellent erosion-corrosion resistance with superior workability and can be obtained relatively inexpensively, so that it can be used suitably for antisticking of marine life.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a copper alloy for preventing the attachment of marine organisms, and is used for seawater introduction log screens in power plants, etc., the inner and outer surfaces of seawater introduction pipes, the outer panels of ships, the outer surfaces of steel pipe mines, It can be used in parts such as floating bridges, buoys, seawater pump piping, and piping parts where marine life attaches and where it is necessary to prevent blockages, increased weight, and increased seawater resistance.

[Conventional technology]

Conventionally, steel, copper alloys, antifouling paints, and the like have been used as antifouling measures for the above-mentioned facilities and equipment, etc., to which marine organisms are likely to adhere.

However, antifouling paint not only loses its antifouling performance after 1 to 2 years, but is also harmful to the human body when applied, and because the paint film is soft, it is easily scratched by driftwood, etc., and may peel off. There are concerns.

In addition, as a conventional copper alloy, cupronickel (90%
Cu-10%Ni), but this alloy has good corrosion resistance, so there is little elution of Cu ions, which are effective for antifouling properties.
It is hard to say that the antifouling performance is excellent.

JP-A-57-583 as a copper alloy for preventing the adhesion of marine organisms
7 is disclosed, but this alloy contains Mn: 5-30%
At least one kind selected from Sn: 5% or less, Al: 8.5% or less, Zn Niia% or less, Fe: 2.5% or less, Ni: 25% or less. Consisting of Cu
- It is a Mn-based alloy, and as a result of a seawater immersion test, its antifouling properties were good, but Cu.

The amount of Mn i-Kanayama was considerably higher than that of cupronickel, and therefore the corrosion resistance was inferior.

The present inventors previously invented a copper alloy with excellent antifouling performance and disclosed it in Japanese Patent Application No. 59-263520. This alloy is as follows. That is, Ni: 5 to 10 in weight ratio
%, Mn: 1 to 5%, and further contains Fe, Sn,
3% each of two or more types selected from Pb and Sb
The following and (Fe + Sn + Pb + Sb): 3
This is a steel alloy for preventing the adhesion of marine organisms, which is characterized by containing Cu in the range of ~8%, with the remainder consisting of Cu and trace amounts of impurities, and has achieved some success.

[Problem that the invention seeks to solve]

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to provide a steel alloy for preventing the adhesion of marine organisms, which has antifouling properties equivalent to those of the conventional Cu-Mn system and excellent corrosion resistance. Specifically, the target is a copper alloy that satisfies the following five items.

(a) Able to maintain antifouling performance for a long time.

(b) No maintenance is required to maintain antifouling performance.

(c) Excellent erosion and corrosion resistance.

(d) Good workability.

(e) It should be relatively inexpensive.

[Means for solving problems]

As a result of several years of durability testing of corrosion-resistant metal materials in the marine environment, the present inventors have confirmed that so-called pure copper and copper alloys of 999% Cu have poor antifouling performance. However, the corrosion resistance of pure copper +,1 was inferior to that of cupronickel, and some shellfish adhesion was observed after long-term immersion in seawater, resulting in problems in erosion resistance.

On the other hand, it was confirmed that cupronickel has excellent corrosion resistance and m erosion resistance, but is inferior in antifouling performance.

The copper alloy according to the present invention has only the advantages of both.
Its gist is as follows.

That is, in terms of weight ratio, Nl: 5 to 10%, Mn: 1 to
5%, Pb: 1 to 10%, and the balance is Cu and trace amounts of impurities.

The reasons for limiting the composition of the copper alloy according to the present invention will be explained.

Ni: Ni has the effect of controlling the elution of Cu and is also effective in improving erosion resistance and corrosion resistance, but at 5%
If the amount is less than 10%, this action/effect will be extremely small, and if it is more than 10%, the corrosion resistance will be excessively improved, resulting in C
Since the elution amount of u decreases and the antifouling property deteriorates, it is limited to a range of 5 to 10%.

Mn: Mn requires at least 1% or more to impart antifouling performance, but if it exceeds 5%, the amount of Mn eluted increases and corrosion resistance deteriorates. Therefore, considering both corrosion resistance and antifouling properties, the content was limited to a range of 1 to 5%.

Pb: Pb1. An element that controls the elution amount of tCu,
In the range of 10%, the amount of pb eluted is small and stable. However, if the amount exceeds 10%, the amount of leached Pb increases and the corrosion resistance deteriorates, so the content was limited to a range of 1 to 10%.

〔Example〕

A seawater immersion test was conducted for the steel alloy according to the present invention and a comparative material for one year, and as a result, the antifouling performance was evaluated, the amount of corrosion, and the amount of elution of each element were measured. The results are shown in Table 1.

The remaining inventive materials in Table 1 are six types: A, B, C, D, E, and F. Comparative material No. 1 is pure copper;
2 is 90% Cu-10% Ni Cup o=Kkel,
Both are hot-rolled ingots that have been vacuum melted in a 50 kg high-frequency melting furnace. The test piece for the seawater immersion test has a thickness of 5
The ram was 100 cm wide and 200 cm long, and was immersed in the ocean at a depth of 160 cm (about the tide level at low tide). The test period is one year from May 1980 to May 1980.

The elution amount of each element that prevents or controls the adhesion of marine organisms was measured by elution amount into artificial seawater in a laboratory. The elution amount is calculated by adding a surface area of 1 in lIV artificial seawater.
A test piece of 00d was immersed and left at room temperature for one month, and each compositional element in the artificial seawater was analyzed. The antifouling performance in Table 1 is evaluated based on the proportion of the area covered by marine organisms to the total area of the test piece, where O indicates less than 3%, Δ indicates 3 to 10%, and X indicates 10% or more. .

The relationship between the antifouling performance, the amount of corrosion, and the amount of elution will be explained based on the test results shown in Table 1.

(a) Comparative material No. 2 cupronickel and N0
No. 3 has excellent corrosion resistance, but as a result, the amount of Cu eluted is small and the antifouling property is poor. Comparative material No. 1, pure copper, has eluted C.
The amount of u is extremely high, reaching 131 ppm, resulting in poor corrosion resistance.

(b) Comparative material No. 4 does not contain Ni and has a large amount of Mn added, so it has excellent antifouling performance, but the amount of eluted Cu and the amount of corrosion are large.

(c) Comparative material No. 5 has Pb exceeding 10% and N
o, 6. Because Pb is less than 1%, in No. 5, Pb elutes preferentially and the elution of Cu is hindered, resulting in a large amount of corrosion and poor antifouling performance. On the contrary, in No. 6, the amount of Cu eluted was slightly small, and the antifouling performance was slightly inferior.

(d) In the present invention materials A, B, C1D, and ESF, Ni: 5
．． 58-9.41%, Mn: 1.10-4.88%
, Pb: varied between 1.15 and 908, all of which had excellent antifouling performance, and the amount of Cu eluted was 65 to 72 pp.
It is stable at m. Although both the elution amount and the corrosion amount tend to increase slightly as the amount of Pb added increases, the corrosion amount remains stable at 12 to 17 mg/cd. Since the corrosion rate in this case is about 0.0015 mm, the corrosion resistance performance is sufficient.

The above comparative tests show that the copper alloy according to the present invention has a significantly superior performance in preventing the adhesion of marine organisms, compared to conventional copper or copper alloys, and compared to comparative materials that do not satisfy the limited composition of the present invention. I understand that.

〔Effect of the invention〕

As is clear from the above examples, the copper alloy according to the present invention contains Nl: 5 to 10%, Mn: 1 to '5%, and pb:
By using an appropriate composition containing 1 to 10% of Cu and the remainder consisting of Cu and trace amounts of impurities, the following effects could be achieved.

(a) Appropriate elution of Cu ions, which are effective for antifouling performance,
In addition, it has appropriate corrosion resistance, so even if it is immersed in seawater for a long time, it can prevent marine organisms from adhering to it, and does not require any maintenance during this period.

(b) Excellent erosion and corrosion resistance.

(c) Good workability.

(d) It is relatively inexpensive.

We were able to obtain an excellent copper alloy that satisfies all of the requirements listed above as an alloy for preventing the adhesion of marine organisms.

Claims (1)

[Claims] (1) Ni: 5 to 10%, Mn: 1 to 5% by weight,
A copper alloy for preventing the adhesion of marine organisms, characterized by containing 1 to 10% of Pb, with the remainder consisting of Cu and trace amounts of impurities.