JP2629701B2 - Galvanic anode and method of manufacturing the same - Google Patents

Description

The present invention relates to a galvanic anode and a method for producing the same. More specifically, the present invention relates to a galvanic anode used for corrosion prevention by being attached to a steel structure, and a method for producing the same by a cast-in method.

(Prior Art) Conventionally, cathodic protection utilizing current action has been widely used for corrosion protection of prepared structures such as port structures, tanks, ships, and the like. There are cathodic protection and anodic protection as cathodic protection, but in many cases, cathodic protection is used in which a current flows in a direction opposite to the corrosion current. A galvanic anode made of a metal with a lower potential than Fe, such as an Al-based, Mg-based, or Zn-based metal, is attached to a steel structure, that is, a steel material surface, and a kind of sacrificial anode action is used to protect the steel material from corrosion. The anode method is one of them.

FIGS. 1 (a) and 1 (b) are schematic explanatory views showing an example of the production of a galvanic anode used for cathodic protection of a galvanic anode system conventionally performed generally, and FIG. FIG. 1B is a longitudinal sectional view of the casting mold, and FIG. 1B is a sectional view taken along line AA in FIG.

First, when the galvanic anode 10 is manufactured by the cast-in method, as shown in the drawing, the inside of the mold 12 is partitioned by the lower casting frame 14 so as to have a predetermined anode size, and the mounting arms 15 and 15 are separated. A mandrel 16 is erected on top of this, and an upper casting frame 18 is further placed thereon, and then a lid 20 is placed to form a mold, and then a molten metal is fed from a feeder 22 provided on the lid 20. The molten alloy is poured to form the anode body 24.

The current-carrying anode 10 thus cast has a mounting arm 15 supporting a mandrel 16, as shown in a schematic side view thereof in FIG.
Both ends 28 of the 15 are attached to the corrosion-resistant steel 30 by welding, and corrosion is prevented by the potential difference between the galvanic anode 10 and the corrosion-resistant steel 30.

Japanese Utility Model Publication No. 44-21456 discloses an example in which the above-described mandrel and mounting arm are formed of the same member.

By the way, such a conventional galvanic anode is usually 30 to
A mandrel having a width of 80 mm is used, and the length of the welded joint with the corrosion-resistant steel at both ends is about 30 to 100 mm. For this reason, such a conventional galvanic anode, when it is attached to a harbor structure such as a steel cell, steel sheet pile, and steel pile, and applied to its corrosion prevention, the strength of the welded joint and the mounting arm is not sufficient, During the construction work, problems such as a detachment of the welded joint and breakage of the mounting arm of the mandrel often occur.

For example, if a galvanic anode is attached to the above-mentioned steel cell in advance, and the steel cell is driven into the soil to be buried, the vibration at that time may cause the welded joint to come off or to attach a mandrel. The arm may be broken.

Also, if the galvanic anode is installed in the sea after the steel cell is inserted, the rock stones that are thrown into the sea floor to stabilize the steel cell will collide with the galvanic anode that has been installed. However, as described above, the welded joint may come off, or the mounting arm exposed to the outside may be broken, resulting in a reduction in the anticorrosion function or no function at all.

On the other hand, it is conceivable to install the galvanic anode after the penetration, but such work is dangerous because it is carried out in the sea and depends on the marine conditions, the work time is limited, etc.
Efficiency is also bad.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art, and can be installed in advance in a steel structure having strict working conditions and operating conditions. Another object of the present invention is to provide a galvano anode capable of sufficiently obtaining a mounting strength that does not cause breakage of a mounting arm of the galvano anode during the operation, dropout of the galvano anode, and the like, and a method of manufacturing the galvano anode.

(Means for Solving the Problems) Here, the present invention relates to a galvanic anode for anticorrosion of a structural structure, a pedestal having a contact surface corresponding to a surface to be protected, and a side opposite to the contact surface. A metal core constituting a galvanic anode body integrally formed on the pedestal by casting the core metal on the pedestal, and forming a bottom portion of the galvanic anode material Provided on at least a part of the base,
And an extended edge welded to the material to be protected.

According to the present invention, preferably, the mandrel is completely cast in the anode body, in which case there is no part protruding to the outside, so that an external force acts on the support arm exposed to the outside as in the prior art. In addition, even if an external force acts on the anode body itself, the current-carrying anode does not break or fall off.

Further, from another aspect, the present invention provides a pedestal having an opening serving as a pouring port and having a mandrel attached thereto, assembling the mold such that the side on which the mandrel is attached is inside the mold, A molten metal of the anode body metal is poured into the mold from the part, and the flow rate of the molten metal in the pouring port is adjusted so that the pedestal surface and the pouring port are flush with each other. It is a manufacturing method of.

As described above, according to the preferred embodiment of the present invention, the conventional mold lid can be omitted by placing the pedestal on the upper end of the mold during casting, and the casting frame for partitioning is divided into upper and lower parts. The casting operation, including mold making, is greatly simplified since there is no need to do so.

Further, since the anode body is formed on the pedestal by casting the mandrel, the bonding strength between the anode body and the mandrel is equal to or higher than that of the related art.

Further, the galvanic anode according to the present invention can be attached to a steel material in advance before constructing a steel structure. Therefore, the mounting is easy, and the area of the welded joint to the steel structure is greatly expanded as compared with the case where the mounting arm is used as in the related art, so that the mounting strength is remarkably improved.

(Operation) Next, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 3 (a) is a schematic side view showing a galvanic anode according to the present invention, and FIG. 3 (b) is a schematic plan view thereof. The same members as those in FIGS. 1 and 2 are denoted by the same reference numerals.

First, as shown in FIG. 3, according to the present invention, a flat base 30 having a width of 200 mm and a flow of 580 mm is provided. On the upper surface of the pedestal 30, four mountain-shaped mandrels 32 are fixedly opposed to each other at regular intervals by welding in order to strengthen the connection between the pedestal 30 and the anode body 24. In the illustrated example, the mandrel 32 has a size of 50 × 50 × 6 t (mm), and a bar-shaped mandrel 33 having a diameter of, for example, 9 mm is provided between the mandrels 32.

The anode body 24 made of a low-potential metal, for example, a low-potential metal such as zinc, aluminum or magnesium,
Is integrally formed by casting the anode body metal on the pedestal 30, and its cross section has an appropriate shape such as a trapezoid or a square.

Therefore, anode body 24 is integrated with pedestal 30 by mandrels 32 and 33 to form galvanic anode 10.

At least a part of the pedestal 30 is provided with an extended edge 31 at the periphery in the illustrated example, so that it is welded to a material to be protected (not shown). Therefore, the lower surface of the pedestal 30 has a shape corresponding to the contact surface of the material to be protected, and comes into close contact during assembly.

As described above, in the present invention, the anode body metal is cast on the pedestal 30, but in a preferred embodiment, the pedestal 30 is cast on the mold to omit the use of the conventional mold lid. You may make it also serve as a lid. Accordingly, in the illustrated example showing the preferred embodiment, reference numeral 36 denotes a pouring opening 36 formed at the center of the pedestal 30 for pouring a molten alloy of the anode body, as described later. The molten alloy is poured up to the top of the pouring port at the opening, so that the pedestal surface and the molten metal are on the same surface,
Injected. In the illustrated example, this is a hole having a diameter of about 100 mm.

As described above, the galvanic anode 10 of the present invention includes the pedestal 30, the mandrel 32 mounted on the pedestal 30, and the anode body 24 formed on the pedestal 30 by casting the mandrel.

FIGS. 4 (a) and 4 (b) are schematic cross-sectional views each showing a preferred embodiment in the case where the pedestal 30 also functions as a mold lid in the method of manufacturing the galvanic anode according to the present invention. According to the illustrated example, the pedestal 30 on which the above-described mandrel 32 is attached is placed on the upper surface of a mold 40 having a predetermined shape so that the mandrel 32 is in the mold, and the center of the pedestal 30 is poured. For example, the anode body 24 in which a molten metal such as an Al alloy is poured from the opening 36 and the core metal 32 is cast can be formed on the pedestal 30. FIG. 4 (b) is a sectional view taken along the line AA of FIG. 4 (a).

In a modified example of the casting operation, it is also possible to pour the molten metal into the mold via a water heater, though not shown, without pouring directly into the opening 36.

FIGS. 5A to 5C are schematic side views showing a modified example of the shape of the base 30 and the mandrel 32 fixed thereto. The shape of the mandrel and the form of attachment to the pedestal are not particularly limited, but it is preferable that the mandrel has a shape that does not easily come off.

The galvanic anode of the present invention is configured as described above, and may be attached to a corrosion-resistant steel material by welding using a pedestal. Therefore, in that case, the material of the pedestal is selected to be easily welded to steel. When the surface of the corrosion-resistant steel material is a curved surface, the bottom surface is also preferably a curved surface having the same radius of curvature.

FIG. 6 is an explanatory view of a use state when the galvanostatic anode 10 according to the present invention is attached to, for example, a steel cell 46 installed on the seabed for revetment and its corrosion protection is performed.

Before driving the steel cell 46, the galvanic anode 10 according to the present invention is mounted at a predetermined position on the outer peripheral surface thereof. In mounting, the back surface of the pedestal of the galvanic anode is brought into contact with the outer peripheral surface of the cell, and the pedestal and the steel cell are directly welded and joined. Welding should be performed with sufficient strength so that the anode of the galvanic anode does not fall out during driving of the steel cell or subsequent work.
This is performed for the entire circumference of the pedestal or a part of it.

The steel cell provided with the galvanic anode in this manner is driven into the seabed by a conventional method, and thereafter, backing stones 48, stilts 50, and sand 52 are charged.

(Effects of the Invention) As described in detail above, the galvanic anode according to the present invention is integrally formed from a pedestal, a mandrel mounted on the pedestal, and an anode body in which the mandrel is cast. Therefore, the anode body is firmly joined to the pedestal by means of the mandrel, and the strength of the galvanic anode itself is equal to or higher than that of the conventional type.

On the other hand, since the galvanic anode is attached to the surface of the corrosion-protected steel material by welding or the like using the pedestal, the area of the welded joint is increased as compared with the related art, and sufficient attachment strength is obtained.

For this reason, work such as driving can be performed after the galvanic anode according to the present invention has been attached to a steel structure such as a steel cell whose working conditions and operating environment are severe, and vibrations and subsequent stoning at this time can be performed. Even at times, the welded joint does not come off and the galvanic anode does not fall off or break down, and is sufficiently suitable for preventing corrosion of this type of structure.

In addition, the manufacturing method also does not need to use the casting frame for partitioning divided vertically, and when the pedestal is placed on the upper end of the mold, the pedestal also serves as the mold lid. The use of the conventional mold lid can be omitted, and therefore, the manufacturing method can be simplified, which is suitable for mass production.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are schematic illustrations of a method for manufacturing a conventional galvano anode; FIG. 2 is a schematic side view of a conventional galvano anode; FIGS. 3 (a) and 3 (b) FIGS. 4A and 4B are schematic side views and plan views, respectively, of the galvanic anode according to the present invention; FIG. (C) is a schematic side view showing a modified example of the shape of the pedestal used in the present invention and the mandrel to be attached thereto; and FIG. 6 is an explanatory view of the use situation of the galvanic anode according to the present invention. 10: current anode, 24: anode body 30: pedestal, 32: mandrel 33: mandrel, 36: opening

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Real opening Sho-51-117820 (JP, U) Real opening Sho-56-111169 (JP, U) Real opening Sho-58-186359 (JP, U) Real opening Sho-60- 75464 (JP, U) Jiko 36-18995 (JP, Y1)

Claims (2)

(57) [Claims] An anticorrosion galvanic anode for a steel structure, comprising: a pedestal having a contact surface corresponding to a surface to be protected; a mandrel mounted on the pedestal opposite the contact surface; This mandrel is cast-in, a galvanic anode metal material constituting a galvanic anode body integrally formed on the pedestal, and provided on at least a part of the pedestal constituting a bottom portion of the galvanic anode material. A current flowing anode comprising an extended edge portion welded to the material to be protected. 2. A pedestal having an opening serving as a pouring port and having a mandrel attached thereto, assembling a mold such that the side on which the mandrel is attached is located inside the mold, A method for producing a galvanic anode for corrosion prevention on a manufactured steel structure, comprising injecting a molten metal into a mold and adjusting the amount of molten metal at a pouring port so that a pedestal surface and a pouring port are flush with each other.