JP2010185180A - Method for repairing zinc coating of steel structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively and efficiently repair a zinc coating of a steel structure. <P>SOLUTION: This method for repairing the zinc coating of the steel structure includes: a step of objectively determining the secular change of the zinc coating of the steel structure by means of a spectrocolorimeter; a step of determining a repair place on the basis of the result on the determination; a step of removing red rust of an alloy layer in the repair place; and a step of applying a zinc paint over the repair place. The step of determining the secular change is objectively performed by measuring the spectral reflectance of the surface of the steel structure by means of the spectrocolorimeter and comparing the result of measurement with a premeasured spectral reflectance in a typical secular-change state for determining the secular change of the film. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for repairing a zinc coating, and more particularly to a method for repairing a zinc coating on a steel structure.

  Many steel materials used for steel structures are provided with a hot-dip galvanized film to prevent corrosion and rust. In order to protect this hot dip galvanized film and to improve its appearance, there is a case in which a coating with a normal paint is further applied on the hot dip galvanized film.

  However, when the entire coating including the coating film is deteriorated due to aging, the coating film is peeled off and red rust is generated in the hot dip galvanized film. The coating film repair is shortened every time and the coating film thickness is enlarged. When the coating film is repaired without completely removing the red rust, the red rust expands and the coating film may peel off in a short period after the repair.

  In recent years, zinc paints have been developed and used for repairing galvanized films instead of general paints. This zinc paint is a mixture of zinc powder in a special resin solvent and exhibits an electrochemical action equivalent to that of a hot-dip galvanized film. As an example of such a zinc paint, there is one marketed by Roval Corporation under the trade name “ROVAL” (Non-Patent Document 1).

  On the other hand, the present applicant has previously proposed a “aging determination method for hot-dip galvanized film” (Patent Document 1). This determination method measures the spectral reflectance of the surface of the hot-dip galvanized film with a spectrocolorimeter, compares the measurement results with the pre-measured spectral reflectance of a typical aging state, and determines the aging of the film. is doing.

JP 2004-333201 A

Web page “Coating zinc plating” (http://www.roval.co.jp/)

  Large-scale steel structures (for example, substations, power transmission towers, iron bridges, lighting towers, material warehouses, etc.) have places where it is difficult to observe changes over time in hot-dip galvanized coatings. There may be individual differences.

  In patent document 1, although the secular change of the hot-dip galvanized film can be determined objectively, no specific countermeasure has been proposed for the repair of the film after the determination. On the other hand, Non-Patent Document 1 provides an effective zinc paint for repairing a deteriorated hot dip galvanized film, but an objective determination method for the secular change of the hot dip galvanized film for large-scale steel structures and It does not suggest any specific repair method.

  Accordingly, an object of the present invention is to provide a method for effectively and efficiently repairing a zinc coating on a steel structure.

  The method of repairing a zinc coating of a steel structure according to the present invention includes a step of determining a secular change of a hot dip galvanized film of a steel structure, a step of determining a repair point based on the determination result, and a red rust of an alloy layer at the repair point. And a step of applying zinc paint to the repair site.

  In the stage of judging the secular change, the spectral reflectance of the surface of the steel structure is measured with a spectrocolorimeter, the measurement result is compared with the spectral reflectance measured in advance in a typical aging state, and the aging of the film is determined. It is done objectively by judging.

  The step of removing the red rust of the alloy layer can be performed using a manual tool or a power tool. The step of applying the zinc paint can be performed using a paint brush or a paint spray gun.

  According to the method of the present invention, it is possible to effectively and efficiently repair the zinc coating of the steel structure. In addition, since the applied zinc paint is substantially integrated with the existing hot-dip galvanized film, it is possible to determine the secular change in the same way even after application, and to deal with corrosion before it penetrates into the steel of the steel structure. .

FIGS. 1A to 1C are partial cross-sectional explanatory views of the surface of a steel structure, and schematically show the aging state of zinc coating. FIGS. 2A to 2C are partial cross-sectional explanatory views of the surface of a steel structure, and a process sequence in which the method of the present invention is applied to repair a deteriorated portion of the zinc coating. Is shown schematically. It is a figure which shows another application form when the method of this invention is applied in order to repair the degradation part of zinc coating corresponding to the (C) figure of FIG. It is a figure similar to FIG. 3 which shows another application form when the method of this invention is applied in order to repair the degradation part of zinc coating.

  Next, with reference to FIG. 1 and FIG. 2, the Example of the repair method of the zinc coating of the steel structure based on this invention is demonstrated.

  Before describing the embodiment of the present invention, first, with reference to FIG. 1, the aging state in the zinc coating in which the zinc paint is applied on the hot dip galvanized film of the steel structure will be described. 1 (A) to 1 (C) are partial cross-sectional explanatory views of the surface of a conventional steel structure, and schematically show an aging state of zinc coating.

  FIG. 1A shows a normal state of a zinc coating 10 of a steel structure (not shown). The zinc coating 10 includes a hot-dip galvanized layer composed of an alloy layer (alloy of iron and zinc) 12 and a zinc layer 13 in order from the lower layer on the surface of a steel material 11 of a steel structure, and zinc applied on the hot-dip galvanized layer. It is formed from the paint layer 14. The steel structure is mainly a large-scale steel structure, such as a substation, a transmission line tower, a steel bridge, a lighting tower, a material warehouse, and the like. The zinc paint is a mixture of zinc powder in a special resin solvent. For example, “Roval” (registered trademark) as disclosed in Non-Patent Document 1 described above is used. This zinc paint can increase the zinc content in the dried coating film to 96%, and an effect equivalent to that of hot dip galvanizing can be obtained at room temperature.

  Over time, the zinc coating 10 progresses in deterioration. In the initial stage, as shown in FIG. 1B, the thickness of the zinc paint layer 14 first decreases. When the deterioration further progresses, as shown in FIG. 1C, the zinc paint layer 14, the zinc layer 13, and the alloy layer 12 are partly peeled, and the recessed hole 15 is generated. In the depressed hole 15, the alloy layer 12 is exposed to the atmosphere, and a red rust layer 16 is generated. Before reaching this state or before that, the zinc coating 10 needs to be repaired.

  Then, the repair method of the zinc coating of this invention is implemented. An embodiment of the method for repairing a zinc coating according to the present invention will be described with reference to FIGS. 2 (A) to 2 (C) are partial cross-sectional explanatory views of the surface of a conventional steel structure, and the method of the present invention is applied to repair a deteriorated portion of the zinc coating. The process sequence is shown schematically.

  FIG. 2A is a view similar to FIG. 1C. In this deteriorated state, as described above, a part of the zinc paint layer 14, the zinc layer 13, and the alloy layer 12 is peeled off and the depressed hole 15 is generated. In the depressed hole 15, the alloy layer 12 is exposed to the atmosphere, and a red rust layer 16 is generated.

  In a large-scale steel structure, an inspector can directly observe with the naked eye to determine the location and degree of the coating deterioration state. However, the direct observation by the inspector may cause oversight or individual differences, and it may be difficult to determine the deterioration state immediately before the deterioration state shown in FIG. .

  Therefore, it is desirable to objectively determine the secular change of the zinc coating using a spectrocolorimeter. For example, the technique disclosed in Patent Document 1 described above can be applied to an objective determination method using a spectrocolorimeter. That is, the spectral reflectance of the surface of the steel structure is measured with a spectrocolorimeter, and the measurement result is compared with the spectral reflectance measured in advance in a typical aging state to determine the aging of the film. Various devices such as a fixed type, a mobile type, and a portable type are commercially available. Any type of spectrocolorimeter may be selected according to the situation at the site.

  A repair location is determined based on the determination result. The determination result is recorded on a recorder separately installed on the ground, and at the same time, directly marked on the repaired portion of the steel structure.

  Next, as shown in FIG. 2 (B), the red rust 16 (FIG. 2 (A)) of the alloy layer 12 at the repair location (recessed hole 15) is removed. This red rust removal can be performed using a manual or power tool.

  Finally, as shown in FIG. 2C, zinc paint is applied to the repaired portion (the recessed hole 15). The new zinc paint layer 14 b covers the previous zinc paint layer 14 a and fills the recessed hole 15. The new zinc coating layer 14b and the previous zinc coating layer 14a are united with each other. In this way, the new zinc coating 10b is formed. The new zinc paint is applied using a paint brush or paint spray gun.

  In the above description, the new zinc paint layer 14b has been described so as to cover the previous zinc paint layer 14a including the repaired portion. However, as shown in FIG. It will be readily appreciated that the desired effect can be achieved by partially coating the layer 14b to fill it to form the new zinc coating 10c. Further, in the above description, the steel structure was covered with the zinc coating layer 14 coated on the hot dip galvanized layer composed of the alloy layer 12 and the zinc layer 13 as the object to be treated. Even if it has only a layer, as shown in FIG. 4, the new zinc coating layer 14b is applied on the hot dip galvanized layer to form the new zinc coating 10d, thereby realizing the desired effect in the same manner. It will be easy to understand what you can do.

  The present invention can be applied not only to a large-scale steel structure but also to a small-scale steel structure. Further, in the above description, the zinc coating of the steel structure has been described with the configuration in which the zinc paint is applied on the hot dip galvanizing, but it is obvious to those skilled in the art that the present invention can be similarly applied even when only the hot dip galvanizing is applied. It is. Furthermore, even when a normal paint is used in place of the zinc paint, the method of the present invention is similarly determined by determining a repair-required portion based on the presence or absence of a phenomenon such as a normal paint swell or peeling. Can be applied.

10 Zinc coating 10b, 10c, 10d New zinc coating 11 Steel layer 12 Alloy layer 13 Zinc layer 14 Zinc paint layer 14a Pre-zinc paint layer 14b New zinc paint layer 15 Recessed hole (repair location)
16 Red rust

Claims (6)

Determining the secular change of the zinc coating of the steel structure;
Determining the repair location based on the judgment result;
Removing the red rust of the alloy layer at the repair location, applying zinc paint to the repair location,
Repair method of zinc coating of steel structure consisting of   In the step of determining the secular change, the spectral reflectance of the zinc-coated surface of the steel structure is measured with a spectrocolorimeter, and the measurement result is compared with a pre-measured spectral reflectance of a typical aging state. The covering repair method according to claim 1, wherein secular change is determined.   The coating repair method according to claim 1, wherein the step of removing red rust of the alloy layer is performed using a manual tool.   The covering repair method according to claim 1, wherein the step of removing red rust of the alloy layer is performed using a power tool.   The coating repair method according to claim 1, wherein the step of applying the zinc paint is performed using a paint brush.   The coating repair method according to claim 1, wherein the step of applying the zinc paint is performed using a paint spray gun.

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