JPS6148547A - Corrosion resistant copper alloy for ocean - Google Patents

Abstract

PURPOSE:To obtain a corrosion resistant Cu alloy for the sea provided with resistance to dezincification and fouling by seaweeds by adding specified amounts of An, Al, Sn and P to Cu so as to inhibit a dezincification phenomenon. CONSTITUTION:The composition of a Cu alloy is composed of, by weight, 20- 37% Zn, 0.05-0.5% Al, 0.05-0.4% Sn, 0.01-0.05% P and the balance Cu with inevitable impurities. 0.05-0.5 Ni may be added to the composition. The Cu alloy has dezincification resistance and superior resistance to fouling by seaweeds.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is used in the marine environment, such as wire mesh for cages, intake grates, covers for steel piles, etc. This article concerns a corrosion-resistant copper alloy that has both anti-algae and dezincing properties.

[Conventional technology]

In general, corrosion-resistant metal materials used in the ocean or in contact with tidal zones, etc. have functions such as strength that correspond to individual uses, as well as less attachment of organisms such as shellfish and algae (hereinafter referred to as anti-algae properties). ) is required.

In order to ensure these anti-algae properties, a method of applying a paint containing a tin compound has been known, but recently 90 Cu
-1Q This study shows that cupronickel, represented by Ni alloys, is being used as material for fish tanks, intake grids, etc. This takes advantage of the effect of Cu ions that are gradually eluted from copper alloys into seawater, which prevents organisms such as shellfish and algae from adhering to them.

However, with the former coating method using a paint containing a tin compound, problems such as deterioration of the paint, longevity, and poor construction cannot be avoided, and it is difficult to expect a long service life. In addition, white copper is
Although it has excellent algae-proofing properties and corrosion resistance, it has the disadvantage that the corrosion-resistant film becomes thicker after several years and the amount of Cu ions eluted decreases, making it easier for algae to adhere.Also, the metal price is high, which limits its use.

On the other hand, when low-cost brass is used in the ocean, it has excellent anti-algae properties, but it suffers from dezincification corrosion and its strength decreases over time, making it unsuitable for use.Therefore, the development of corrosion-resistant alloys for marine use is difficult. It was requested.

[Purpose of the invention]

The purpose of the present invention is to provide a corrosion-resistant copper alloy for marine use which suppresses the dezincification corrosion of brass, ensures long-term elution of copper ions, has anti-algae properties, and has excellent general corrosion resistance and strength. be.

[Problem that the invention seeks to solve]

The present invention has been made to achieve the above-mentioned object. For example, when using copper alloy for cage wire mesh, the required properties (1) The elution of ions from the gaseous material.

(2) To ensure elution of copper ions, the amount of elution should not be too large. In other words, the lifespan should not be shortened due to lack of corrosion resistance.

(3) Membrane component corrosion phenomena such as dezincification corrosion should not occur.

(4) Strong enough to withstand typhoons, etc., and capable of thinning.

(5) Good workability.

(6) Resistant to local corrosion.

(7) It must be made of inexpensive material. Etc. is rolled down.

[Means for solving problems]

The inventors of the present invention have made the following findings as a result of intensive research into the relationship between the four constituent elements of marine corrosion-resistant alloys and the above-mentioned required components, and have thus arrived at the invention. First, Zn is effective in reducing the strength of the alloy Sff and the material cost, and by adding Zn, the amount of copper ions eluted gradually decreases.
It is not so low that it adversely affects algae-proofing properties, but is actually advantageous.

However, since the addition of Zn causes dezincification corrosion, countermeasures are required. That is, if the Zn content is less than 20% by weight, the above-mentioned advantages cannot be obtained sufficiently, and if it exceeds 37% by weight, the workability of the alloy decreases and dezincification corrosion becomes significant.

A1 improves the strength of the alloy, and the addition of Sn and P has the effect of suppressing the elution of copper and ensuring corrosion resistance.

If M is less than 0.05% by weight, this effect will not be sufficient, and if it exceeds 0.5% by weight, a strong film will easily form on the alloy surface, and the amount of copper ions eluted will become extremely large over time. This causes problems in algae prevention and increases the amount of dezincification corrosion.

Sn is very effective in suppressing dezincification corrosion, and if it is less than 0.05% by weight, the effect is insufficient, and if it exceeds 0.4% by weight, the effect of Sn is saturated and at the same time impairs workability.

Note that although Sn and P each have the effect of suppressing dezincification corrosion, when they are added together, they exhibit a synergistic effect of suppressing dezincification corrosion.

Since Ni refines the crystal grains and improves corrosion resistance, it also has the effect of improving strength, so KN is added to the above alloy composition.
Addition of i will further improve the effects of the present invention. When the Ni content is less than 0.05% by weight, the effect is small, and when it exceeds 0.5% by weight, dezincification corrosion tends to occur.

As described above, the first corrosion-resistant copper alloy for marine use of the present invention is Zn 2
0~37wt@, At O, 05~0.5wt%, S
The alloy consists of n0.05 to 0.4% by weight, P 0.01 to 0.05% by weight, and the balance copper and unavoidable impurities.
In addition to the above composition, it consists of 05 to 0.5% by weight of NiO, the balance being copper and unavoidable impurities, and has the characteristic of suppressing the dezincing phenomenon.

The effects of the copper alloy according to the present invention will be described below based on Examples and Comparative Examples.

〔Example〕

Each of the copper alloys shown in Table 1 below is 6! It was melted in a high frequency melting furnace in a graphite crucible and cast into a mold. After the obtained ingot was face-to-face, annealing and rolling were repeated until the final upward rolling rate was 15.
A plate material with a thickness of 1W+ corresponding to μH material falling between ~20% was used. Then, the following test was conducted on this plate material.

■The sample was placed on a rotating water wheel rotating at a circumferential speed of 2 m/h in natural seawater for 100 hours.

Calculate the amount of corrosion from the difference in weight of the sample before and after the test.
It was raining on a daily basis.

■CuC of 75C according to ISO standard for dezincification test
After being immersed in a 1v -2HtO (12,8'/l) solution for one day, the erosion depths at 10 points on the cross section of the sample were determined and the maximum value was expressed in μm.

A test piece measuring 200 m x 100 m was immersed in a practical seawater at a depth of 701 m for one year, and the state of adhesion of organisms was observed.

■A tensile test was conducted to measure tensile strength and elongation.

The results are shown in Table 1 below.

As seen in Table 1, the amount of corrosion increases in the presence of Sn and P added to prevent dezincification corrosion, but tends to decrease with the addition of M. Moreover, as shown in Comparative Example 7, the amount of dezincing becomes D due to Sn and P, but increases slightly when M is added. It is also found that addition of large amounts of M and Ni leads to dezincing. It decreases as the amount of algae-proofing un added increases. Compared to Comparative Example 6, the tensile strength and elongation of other alloys with a large number of additive components showed a tendency for high strength and low elongation, respectively.
, Ni, and Zn can be seen.

Still in Fig. 1 are Cu-34~35zn-o, o2~0.
The relationship between the amount of corrosion and the amount of dezincing when M is added to the 04P 0.21-0.22-8n(-Ni) alloy is plotted from the data in Table 1.

As is clear from FIG. 1, the alloy of the present invention attempts to suppress the amount of corrosion while suppressing dezincification.

Furthermore, as is clear from Table 1, the alloy of the present invention prevents the attachment of organisms such as shellfish and algae through the elution of Cu ions, and also increases the mechanical strength of brass, increasing the reliability of the strength and wires. It is also possible to further improve economical efficiency by reducing the amount of material used by making the diameter smaller.

〔Effect of the invention〕

As is clear from the examples, the marine copper alloy according to the present invention takes advantage of its excellent corrosion resistance and anti-erosion properties, and is suitable for use in the marine environment, such as intake grids, fish tank materials, steel pile covers, and ship exterior panels. It is suitable as a material for use in equipment that handles seawater and prevents living organisms from getting onto it.

[Brief explanation of drawings]

FIG. 1 is a graph showing the corrosion loss and dezincing depth when M is added to the present alloy. Agent Patent Attorney Sanro Kimura Figure 1 0 0.08 02B 0.5
9Affi% 1゜Indication Patent Application 1987-1.68764 2. Name of invention Name of marine corrosion-resistant copper alloy Name (618) Mitsui Mining & Mining Co., Ltd. (Name) 4゜Representative 6. Details subject to amendment Column 7 of "Detailed Description of the Invention" of the book, contents of amendment (1) "By addition" in line 17 of page 4 of the specification is amended to read "by addition". (2) “What are Sn and P?” on page 5, lines 7 to 9.
・Exercise. "P has the effect of suppressing dezincification corrosion, and if it is less than 0.01%, the effect is negligible, and if it exceeds 0.05%, the effect becomes saturated and at the same time, the workability deteriorates. When co-added with P, a synergistic effect is exerted to suppress dezincification corrosion.'' (3) "Waterwheel" on page 6, line 16 is corrected to "waterwheel-like." (4) Correct r75cJ on page 6, line 17 to "75°C." (5) Each numerical value in the [corrosion amount (mdd) J column of Table 1 on page 8] r 48 [1, J → " 48 jr38
0J → “68” “400 J −+ “40” r270J
-+ r27J r' 240 J → " 24jr250
J → ``25'' r49DJ → ``49'' r180j → ``18j [3601→ ``36j and correct them respectively.

Claims (2)

[Claims] (1) Zn20-37wt, Al0.05-0.5wt%, Sn0.05-0.4wt%, P0.01-0.0
A corrosion-resistant copper alloy for marine use characterized by suppressing the dezincing phenomenon consisting of 5% by weight, the balance being copper and inevitable impurities. (2) Zn 20-37% by weight, Al 0.05-0.5% by weight, Sn 0.05-0.4% by weight, P 0.01-0.
A corrosion-resistant copper alloy for marine use characterized by suppressing the dezincing phenomenon, consisting of 0.05% by weight of Ni, 0.05 to 0.5% by weight of Ni, and the balance copper and unavoidable impurities.