JP7083453B2 - Steel material repair method - Google Patents

Description

The present invention relates to a steel material repair method, and more particularly to a steel material repair method suitable for repairing a corroded portion in a steel structure using a steel material such as a bridge, a water gate, a power transmission tower, a building, an offshore structure, and a plant.

The strength, corrosion resistance, heat resistance, magnetic properties, coefficient of thermal expansion, etc. of steel materials can be adjusted according to the carbon content and heat treatment method, and various types of steel materials are manufactured, such as bridges, water gates, and power transmission towers. , Buildings, marine structures, plants, etc. are used for various structures. In these steel structures, steel is often used as a member to support a load and requires a certain strength. On the other hand, steel structures are often installed in a state of being exposed to the outdoors, and the steel material is easily corroded by the adhesion of moisture or the like.

When the steel material is corroded, the wall thickness is partially reduced, the strength is lowered, and there is a risk of buckling. Therefore, it is necessary to repair the corroded steel material, but the above-mentioned steel structure is often large, and it is inefficient to replace the entire steel material due to partial corrosion, and the replacement work is also large. Will be. In particular, when a steel structure is an infrastructure facility such as a bridge, the use of the facility must be stopped when the steel material is replaced, which has a great social impact.

For example, in Patent Document 1, a base treatment step of performing a base treatment on the surface of a steel material of a steel structure to be corrosion-proof, a step of attaching a waterproof adhesive tape to which a waterproof adhesive tape is attached, and a corrosion-resistant metal thin plate are attached on the base treatment step. An anticorrosion method comprising a metal thin plate attaching step is disclosed.

Further, in Patent Document 2, only the existing floating rust is removed, and rust resistance such as red rust and yellow rust adheres to the remaining weathering steel surface, and the rust resistance is maintained for a long period of time. Also disclosed is a process-saving weathering steel anticorrosion method that maintains weathering resistance for a long period of time and enables arbitrary coloring by applying a colored topcoat paint containing a colorant.

Japanese Unexamined Patent Publication No. 2001-81800 Japanese Unexamined Patent Publication No. 2004-97945

By the way, at the time of maintenance (painting, repainting, etc.) of an existing steel structure, it is common to adjust the surface of the steel material by using a blasting device or a power tool. However, in some existing steel structures, it may be difficult to assemble the scaffolding itself, or the scaffolding may be unstable and the substrate may not be sufficiently adjusted.

In the invention described in Patent Document 1, it is described that a blast treatment or a type 2 kelen treatment is performed as a substrate adjustment, and even if it can be applied to a newly constructed steel structure, the existing steel structure can be applied. It may not be applicable to things. On the other hand, in the invention described in Patent Document 2, since only floating rust is removed by a wire brush or the like, it can be applied to an existing steel structure.

However, in the invention described in Patent Document 2, when the coating film is formed on the fixed rust to prevent corrosion, the coating film is a semipermeable membrane and allows oxygen, which is a corrosion factor, to pass through. If the salt concentration of the corroded part is high, it induces the infiltration of water, which is a corrosive factor, and in an outdoor environment, it tends to deteriorate over time due to direct sunlight.

Therefore, it is difficult to suppress the progress of rust by the anticorrosion method using the coating film as described in Patent Document 2, and the swelling of the coating film, the generation of new rust, and the like are induced.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a steel material repair method that can be applied even when the scaffolding is insufficient and can improve the blocking performance of corrosive factors. And.

According to the present invention, it is a steel material repair method for repairing a corroded portion formed on the surface of a steel material, and is a cleaning method for removing stains adhering to the surface of the steel material without removing the rust formed on the corroded portion. It is characterized by including a step, a coating step of applying an adhesive to one surface of a metal foil covering the corroded portion, and a pasting step of sticking the metal foil to the surface of the steel material so as to cover the corroded portion. A method of repairing steel materials is provided.

The cleaning step may have a treatment content of 4 types or less.

The adhesive may be applied to a thickness of about 10 to 1000 μm. Further, the adhesive placed on the corroded portion may be applied thicker than the numerical value of the surface roughness of the corroded portion.

The thickness of the metal foil may be about 20 to 200 μm. Further, the metal foil may be laminated.

The steel material repair method may include a water stopping step of stopping water at the end of the metal leaf attached to the surface of the steel material. The water stopping step may include a step of welding the overlapped portion or the butt portion of the metal foil. Further, the water blocking step may include a step of arranging a paste-like or sheet-shaped water blocking material at the end of the metal foil.

Further, the steel material repair method may include a top coating step of overcoating the surface of the metal leaf attached to the surface of the steel material. Further, the topcoating step may include a step of selecting a paint based on a color chart number.

According to the steel material repair method according to the present invention described above, since the repair is performed without removing the rust on the corroded portion, it is not necessary to substantially adjust the substrate, and even in an environment where the scaffolding is insufficient. Repair work can proceed. Further, by attaching the metal leaf on the corroded portion with an adhesive, it is possible to improve the blocking performance of oxygen and moisture, which are corrosion factors, as compared with the case of repairing with a coating film.

It is a flow figure which shows the steel material repair method which concerns on one Embodiment of this invention. It is a front view which shows the steel material after repair. It is a partial cross-sectional enlarged view of the repair part, (a) shows this embodiment, (b) shows a modification. It is a partial cross-sectional enlarged view which shows the end portion of a metal foil, (a) shows a superposition part, (b) shows a butt part. It is a partial cross-sectional enlarged view in which the water blocking material is arranged at the end of the metal foil, (a) shows a paste-like water blocking material, and (b) shows a sheet-shaped water blocking material. It is a figure which shows the result of the salt spray test.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6. Here, FIG. 1 is a flow chart showing a steel material repair method according to an embodiment of the present invention. FIG. 2 is a front view showing a steel material after repair. FIG. 3 is an enlarged partial cross-sectional view of the repaired portion, where (a) shows the present embodiment and (b) shows a modified example.

As shown in FIGS. 1 to 3A, the steel material repairing method according to the embodiment of the present invention is a method of repairing the corroded portion 2 formed on the surface of the steel material 1, and the corroded portion 2 is covered with the corroded portion 2. A cleaning step Step 1 that removes dirt adhering to the surface of the steel material 1 without removing the formed rust, a coating step Step 2 that applies the adhesive 4 to one surface of the metal foil 3 that covers the corroded portion 2, and a metal foil 3 Step 3 is affixed to the surface of the steel material 1 so as to cover the corroded portion 2, a water stop step Step 4 is to stop the end of the metal foil 3 affixed to the surface of the steel material 1, and affixed to the surface of the steel material 1. The top coating step Step 5 for overcoating the surface of the metal foil 3 is provided.

The cleaning step Step 1 is a step of removing stains adhering to the surface of the steel material 1 at the portion to which the metal foil 3 is attached. The "dirt" removed in the cleaning process is a deposit that can be easily removed with a manual tool such as a brush or a hammer, and includes floating rust.

Conventionally, when repairing a steel material 1 having a corroded portion 2 having rust on the surface, it is common to adjust the substrate before repairing. It is known that there are grades of 1st to 4th grades for substrate adjustment, and the lower the grade number, the higher the grade of substrate adjustment.

"Class 1 keren" means a level in which rust and old coating film are completely removed and the substrate is adjusted mainly by blasting or using a power tool until the surface of the steel material is exposed.

"Type 2 keren" means a level in which the substrate is adjusted mainly with an electric tool or a manual tool until the rust and the old coating film are completely removed and the surface of the steel material is exposed.

"Type 3 Keren" is a substrate adjustment mainly with an electric tool or a manual tool so as to leave an active film (coating film in a healthy state) and remove other defective parts (rust, cracks, swelling). Means the level of doing.

"Type 4 keren" means a level at which the substrate is adjusted mainly with a manual tool or a brush so as to remove powder (including floating rust), dirt, etc. adhering to the surface. Further, in the present embodiment, "4 kinds of keren or less" is intended to include the 4th kind keren and the substrate adjustment (keren) having a lower grade than the 4th kind keren. That is, "4 types or less" means that 1 type to 3 types of keren are not included.

The cleaning step Step 1 in the present embodiment is a step of removing stains with a treatment content of 4 types or less, and is a step of not removing rust (red rust, black rust, etc.) formed on the corroded portion 2. Since the base adjustment of 3 types or more requires large-scale equipment such as power tools and blasting devices, a stable scaffolding is required. One of the purposes of the steel material repair method according to the present embodiment is to be applicable even when the scaffolding is insufficient or unstable, and it is sufficient if dirt that can be removed by a manual tool can be removed. Is.

Then, in the steel material repair method according to the present embodiment, the metal foil 3 is attached on the corroded portion 2 while the rust formed on the corroded portion 2 remains. When repairing the corroded portion 2 while leaving the rust, it is important how to block the corrosive factors such as oxygen and moisture that induce the progress of the rust.

In the repair method of forming a coating film on rust as in the past, the coating film is a semipermeable membrane and allows oxygen to pass through. When the salt concentration of the corroded part is high, it induces the infiltration of water. In an outdoor environment, there are problems such as aging deterioration due to direct sunlight.

Therefore, in the steel material repair method according to the present embodiment, a metal foil 3 having a feature that oxygen and moisture do not pass through and that it does not easily deteriorate over time even in direct sunlight is used. As the material of the metal foil 3, for example, a metal such as aluminum, stainless steel, titanium, copper or an alloy thereof is used.

The thickness of the metal foil 3 is, for example, about 20 to 200 μm. If the thickness of the metal foil 3 is less than 20 μm, wrinkles are likely to occur during construction, and holes may be formed or broken from the wrinkles as a base point, which may reduce the environmental blocking effect. Further, when the thickness of the metal leaf 3 exceeds 200 μm, swelling is likely to occur during construction, and the metal leaf 3 may float or peel off during bonding. Therefore, in the present embodiment, the thickness of the metal foil 3 is adjusted within a range in which wrinkles or wrinkles are unlikely to occur.

Further, since the steel material repair method according to the present embodiment assumes that a relatively large area portion of the steel structure is repaired, the metal leaf 3 is, for example, a square having a size of about several square meters. Alternatively, it is formed in a rectangular shape, and as shown in FIG. 2, the corroded portion 2 is repaired by spreading a plurality of metal foils 3.

The coating step Step 2 is a step of applying the adhesive 4 to the entire adhesive surface (the surface in contact with the surface of the steel material 1) of the metal foil 3. As the adhesive 4, an adhesive that is compatible with the metal foil 3 is used. For example, the adhesive 4 is a one-component modified silicone epoxy resin-based adhesive and a two-component epoxy resin-based adhesive, but is not limited thereto. The term "adhesive" is a general term for substances having high adhesiveness, and is intended to include paints and the like that do not have the name of an adhesive.

The adhesive 4 not only has a function of adhering the metal foil 3 to the surface of the steel material 1, but also has a function of filling a gap between the metal foil 3 and the steel material 1. By filling the adhesive 4 in this way, the air (oxygen) existing between the metal foil 3 and the steel material 1 can be blocked.

As shown in FIG. 2, since the metal foil 3 is attached not only to the corroded portion 2 but also to the surface of the uncorroded steel material 1, the adhesive 4 has a thickness of, for example, about 10 to 1000 μm. Is applied to. Within the thickness range of this degree, the metal foil 3 and the steel material 1 can be formed not only on the corroded portion 2 but also on the surface of the non-corroded steel material 1 and the surface of the steel material 1 having irregularities. The adhesive 4 can be filled in between.

Further, according to the experience of the inventors, the surface roughness of the steel material 1 after the type 4 kelen treatment of the corroded portion 2 is 300 to 400 μm. Therefore, the adhesive 4 arranged on the corroded portion 2 is applied thicker than the numerical value of the surface roughness of the corroded portion 2. That is, the adhesive 4 arranged on the corroded portion 2 is applied to a thickness of 300 to 400 μm or more. By adjusting the coating thickness of the adhesive 4 in this way, for example, as shown in FIG. 3A, the adhesive 4 can be filled between the corroded portion 2 and the metal foil 3.

If the adhesive 4 is applied thicker than necessary, the weight of the metal leaf 3 in the sticking process may increase and the work efficiency may decrease, or the metal leaf 3 may slip off the surface of the adhesive 4. It is not preferable because there is.

The sticking step Step 3 is a step of sticking the metal leaf 3 coated with the adhesive 4 to the surface of the steel material 1. For example, as shown in FIG. 2, a plurality of metal foils 3 are spread on the surface of the steel material 1 having the corroded portion 2. At this time, it is necessary to prevent a gap in which the metal foil 3 is not arranged, at least in the corroded portion 2 and its periphery.

Here, FIG. 4 is a partial cross-sectional enlarged view showing an end portion of the metal foil, where (a) shows a superposition portion and (b) shows a butt portion. FIG. 5 is an enlarged partial cross-sectional view in which a water blocking material is arranged at the end of the metal foil, where (a) is a paste-like water blocking material and (b) is a sheet-shaped water blocking material.

The ends of the metal foil 3 may be overlapped as shown in FIG. 4A, or may be butted as shown in FIG. 4B. As shown in FIG. 4A, when the ends of the metal foils 3 are overlapped with each other, the adhesive 4 is filled between the metal foils 3, so that the moisture from the overlapped portion 3a It is possible to block the infiltration of.

The size and arrangement of the metal foil 3 is not limited to the configuration shown in FIG. For example, the strip-shaped metal foil 3 may be wrapped around the surface of the steel material 1. At this time, the metal foil 3 is wrapped so that the ends of the metal foil 3 are not located on the repaired portion, that is, the ends of the metal foil 3 are located on the surface of the steel material 1 other than the repaired portion. As a result, it is possible to suppress the infiltration of water into the repaired portion.

The water stop step Step 4 is a step of sealing the end portion of the metal leaf 3 attached to the surface of the steel material 1. By such a water stop treatment, it is possible to improve the environmental blocking performance of the repaired portion. For example, as shown in FIG. 4B, when the ends of the metal foil 3 are butted against each other, a slight gap may be formed between the ends of the metal foil 3.

Therefore, the butt portion 3b may be welded by a welding means such as an ultrasonic welding machine with a soldering iron. Further, in the superposition portion 3a shown in FIG. 4A, the ends of the metal foil 3 may be welded to each other.

Further, as shown in FIG. 5A, the paste-like water blocking material 5 may be arranged at the end of the metal foil 3, or as shown in FIG. 5B, the metal foil may be arranged. A sheet-shaped water blocking material 5 may be arranged at the end of 3. Although not shown, a sheet-shaped water blocking material 5 may be arranged on the overlapping portion 3a of the metal foil 3, or a paste-shaped water blocking material 5 may be arranged on the abutting portion 3b of the metal foil 3.

By using the water blocking material 5, for example, the end portion of the metal foil 3 can be stopped from water even in a portion where the adjacent metal foil 3 does not exist, and the environmental blocking effect can be improved.

The topcoating step Step 5 is a step of overcoating the surface of the metal leaf 3 attached to the surface of the steel material 1 with a predetermined paint. The paint can be arbitrarily selected based on the Munsell value and the color chart number of the Japan Paint Manufacturers Association color sample. By applying such a top coat, the surface of the repaired portion can be made to have the same color as the surface of the surrounding steel material 1, and the repaired portion can be made inconspicuous. The paint may contain a rust preventive. In addition, an undercoat and an intermediate coat may be added as needed.

According to the steel material repair method according to the present embodiment described above, since the corroded portion 2 is repaired without removing the rust, it is not necessary to substantially adjust the substrate, and the scaffolding is insufficient. However, repair work can proceed. Further, by attaching the metal leaf 3 on the corroded portion 2 with the adhesive 4, it is possible to improve the blocking performance of oxygen and moisture, which are corrosion factors, as compared with the case of repairing with the coating film.

Further, the metal foil 3 may be laminated as in the modified example shown in FIG. 3 (b). By laminating the metal foil 3, the laminated resin 6 can be arranged on the surface of the metal foil 3. By arranging the laminated resin 6 on the surface of the metal foil 3 in this way, it is possible to suppress damage to the metal foil 3 and improve the adhesiveness with the adhesive 4.

Here, a salt spray test using a test piece will be described. Here, FIG. 6 is a diagram showing the results of the salt spray test. First, a rust plate having rust formed on almost the entire surface of the steel material is prepared under the same conditions.

The "test piece A" is obtained by wrapping the rust plate with aluminum foil without blasting, that is, after removing stains on the surface while leaving rust.

The "test piece B" is obtained by removing stains on the surface of the rust plate without blasting and then forming a coating film on the surface.

The "test piece C" is obtained by blasting the surface of a rust plate to remove rust, exposing the surface of a steel material, and then wrapping it in aluminum foil using an adhesive.

The "test piece D" is obtained by blasting the surface of the rust plate to remove rust, exposing the surface of the steel material, and then forming a coating film on the surface.

The salt spray test is a neutral sodium chloride solution (concentration 5%) in which a test piece is placed in a salt spray test device maintained at a constant temperature (33 to 37 ° C) and atomized from above. This is a test in which the state of rust generated on the surface of the test piece is observed after a certain period of time has passed by spraying. Specifically, it is a test method defined in "JIS K5600 7-1" of the Japanese Industrial Standards.

The results of observation of each test piece after 0 hours, 408 hours, and 1215 hours are shown in the upper, middle, and lower stages of FIG. In the test piece B, rust or swelling had already occurred partially at the stage after 408 hours, and rust or swelling had already occurred on almost the entire surface after 1215 hours.

Further, in the test piece D, rust started to be slightly formed on the surface at the stage after 408 hours, and rust or swelling was partially formed after 1215 hours.

On the other hand, with respect to the test piece A and the test piece C, neither rust nor swelling occurred on the surface of the test piece even after 1215 hours. As a result, the repair method of attaching the metal leaf to the surface of the steel material can significantly suppress the generation of rust after the repair, as compared with the conventional method of repairing the corroded part with the coating film. Recognize.

Further, when comparing the test piece A and the test piece C, considering that there is no change in the state after 1215 hours, even if the rust plate is not blasted and the dirt is removed while the rust remains. It can be seen that the occurrence of rust after repair can be sufficiently suppressed.

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 Steel material 2 Corroded part 3 Metal leaf 4 Adhesive 5 Water-stopping material 6 Laminated resin Step1 Cleaning process Step2 Coating process Step3 Pasting process Step4 Water-stopping process Step5 Topcoating process

Claims (11)

It is a steel material repair method that repairs the corroded part formed on the surface of the steel material.
A cleaning process that removes dirt adhering to the surface of the steel material without removing the rust formed on the corroded portion, and
The coating process of applying an adhesive to one surface of the metal foil covering the corroded part, and
A sticking step of sticking the metal foil to the surface of the steel material so as to cover the corroded portion, and a sticking step.
A steel material repair method characterized by containing. The steel material repair method according to claim 1, wherein the cleaning step is a treatment content of 4 types or less. The steel material repair method according to claim 1, wherein the adhesive is applied to a thickness of about 10 to 1000 μm. The steel material repair method according to claim 1, wherein the adhesive arranged on the corroded portion is applied thicker than the numerical value of the surface roughness of the corroded portion. The steel material repair method according to claim 1, wherein the thickness of the metal foil is about 20 to 200 μm. The steel material repair method according to claim 1, wherein the metal foil is laminated. The steel material repair method according to claim 1, further comprising a water stopping step of stopping water at the end of the metal foil attached to the surface of the steel material. The steel material repair method according to claim 7, wherein the water stopping step includes a step of welding the superposed portion or the butt portion of the metal foil. The steel material repair method according to claim 7, wherein the water blocking step includes a step of arranging a paste-like or sheet-shaped waterproof material at the end of the metal foil. The steel material repair method according to claim 1, further comprising a topcoating step of overcoating the surface of the metal foil attached to the surface of the steel material. The steel material repair method according to claim 10, wherein the top coat step includes a step of selecting a paint based on a color chart number.

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