JP2873980B2 - Rust treatment method for steel surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for generating rust on a surface of a steel material, which generates rust uniformly and with good adhesion on a surface of a stainless steel material in a short time. More specifically, a method for generating rust on a steel material surface by increasing uniform friction and improving the friction coefficient of the steel material surface, thereby increasing the joining strength in joining with a high-tensile steel bolt or the like. It is.

[0002]

2. Description of the Related Art Conventionally, in a joining method using a high-tensile steel bolt applied to the construction of a general steel structure, a complete ingot surface subjected to a grinder treatment or a blast treatment is used.
It is known that a surface on which rust is appropriately generated has a higher friction coefficient, so that good bonding strength can be obtained. As the above-mentioned rust generation, that is, rust generation treatment, generally, a method of leaving a steel material in the air, or applying seawater or the like to the surface thereof and leaving it is adopted.

[0003] However, the above-mentioned method requires a long period of standing before rusting, and particularly in the case of a steel material such as stainless steel which does not easily rust, the standing time is extremely long.
Not an efficient method. In addition, if the leaving time is long as described above, it becomes difficult to control the rusting state. Depending on the leaving time and other rusting environmental conditions, the rusting progresses to a bumpy rust state, and the bumpy rust is removed by a wire brush or the like. In some cases, it is necessary to finish the steel to an appropriate level of rust, and it is extremely difficult to perform an appropriate rusting treatment.
Further, when seawater or the like is applied and left as it is, the seawater or the like cannot be uniformly applied to the surface of the steel material, resulting in uneven application, so that rust cannot be uniformly generated.

[0004]

In view of the above, the present inventors applied a solution comprising ferric chloride and a surfactant to the surface of a steel material to form a uniform rust on the surface of the steel material for a short period of time. (See Japanese Patent Application Laid-Open No. 58-77)
No. 906), and the generated rust has extremely good adhesion to the surface of the steel material and can improve the friction coefficient, so that the joining strength by the bolt can be increased.

[0005] However, the above-mentioned method can enhance the conformability and wettability of the solution to the surface of the steel material to perform uniform application, and can provide uniform rust to a flat surface to be treated. Because of insufficient wettability, this solution could not be maintained for a required processing time on an upright surface to be processed, for example, a standing steel material. Therefore, there has been a demand for a method capable of generating uniform rust in a short time with a simple operation even on the surface of a standing steel material and improving the friction coefficient of the steel material surface.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above, and it is intended that a sheet material in which iron powder is uniformly dispersed is wetted with a ferric solution and adhered on a surface to be treated. The present invention relates to a method for treating rust on a steel material surface.

The iron powder used in the present invention includes:
It is preferable that the purity is as high as possible.
It is preferably about 10 to 10 μm.

The sheet material in which the iron powder is dispersed is not particularly limited in its material, basis weight, thickness, and other properties, and can be selected from paper, cloth, nonwoven fabric, and the like. Those having water permeability (liquid) properties are desirable.

As a method of uniformly dispersing the iron powder in the above-mentioned sheet material, for example, iron powder is added to a volatile solvent such as alcohol and sufficiently dispersed and stirred, and the sheet material is dispersed in the dispersion. After immersion for a short time, it may be pulled up and dried. Further, the dispersion amount of the iron powder in the above sheet material is
It can be controlled by the amount of iron powder added to the dispersion solvent (the concentration of iron powder in the dispersion), but may be set appropriately according to the desired degree of rusting. In the sheet material in which the iron powder is uniformly dispersed, a binder component may be added to the above-mentioned dispersion so that the iron powder does not fall off during the drying step or during storage. As for the sheet material manufactured in this way, it is desirable that the storage environment be kept away from high humidity for the purpose of preventing corrosion of the iron powder dispersed in the sheet material.

According to the present invention, a sheet material in which iron powder is uniformly dispersed as described above is wetted with a ferric solution and adhered to a steel material surface. .
A 1-40% aqueous solution is used. If this concentration is too low, the time until rusting is long, and workability will be impaired. On the other hand, if it is too high, not only is it economically wasted, but the steel material surface is excessively rusted. Practically, the leaving time may be set based on the construction design or the like, and the concentration of the ferric solution may be determined according to the leaving time. The ferric solution used here is a solution in which a compound containing ferric acid (ferric chloride, ferric nitrate, etc.) is used as an aqueous solution and in which ferric ions can exist in a stable state. is there. Further, nitric acid or iron nitrate may be added to the above-mentioned ferric solution for the purpose of preventing excessive rusting so as to have an inhibitory effect. Further, a surfactant may be added to improve conformability wettability with the steel material surface.

The present invention specifically relates to a method of producing a ferrous solution by contacting the above-mentioned sheet material with a steel material surface using a spraying device such as a spray or an applicator such as a brush. May be absorbed (liquid). In the above-described method, when rusting is caused on the surface of the standing steel material, the sheet material may be brought into contact with a support such as a tape. When the present invention is carried out as described above, even when the spray amount or the application amount is somewhat non-uniform, or when there is a part where spraying or application is partially forgotten, the ferric solution in the sheet material Naturally penetrates, and the entire surface in contact with the steel material surface is in a wet state, so that rust can be generated uniformly.

The present invention is not specifically limited to the above-described method, but may be any method as long as the sheet material is wetted with a ferric solution and adhered to the surface of the steel material. For example, when the surface to be processed is relatively flat and has a large area, the sheet material is wound into a roll, dipped in a ferric solution, and then spread on the surface to be processed. You may make it wear.

Next, the rust generation mechanism of the present invention will be described. According to the present invention, as described above, a sheet material is adhered to the surface of the steel material, and iron powder and a ferric solution are present in the sheet material. That is, the ferrous solution in which the iron powder is dispersed is applied (contacted) to the surface of the steel material. Galvanic corrosion, or so-called rust, occurs between the iron powder and the steel material metal due to contact between different kinds of metals. In addition, between the sheet material and steel metal, battery corrosion due to oxygen concentration,
So-called crevice corrosion occurs. Furthermore, when a ferric chloride solution is used as a ferric solution, since chloride ions are a reducing substance, the oxide film on the surface of the steel material is destroyed and activated, causing a potential difference between the ferrous chloride solution and the surrounding passive portion. Activated parts corrode. As described above, the above-mentioned three corrosive effects occur on the surface of the steel material, and rust can be generated in a short period of time.

[0014]

Examples of the present invention will be described below. Example 1 A dispersion prepared by dispersing and dissolving 10 parts of iron powder (average particle size: 1 μm) and 1 part of carboxymethylcellulose in 100 parts of water was prepared. 1.5 mm) was immersed in the dispersion and dried to prepare a sheet material. Next, the above-mentioned sheet material was stuck on the surface of the SUS304 test piece. Then, a solution in which 10 parts of ferric chloride, 1 part of nitric acid, and 0.1 part of a surfactant were dissolved in 100 parts of water was spray-sprayed on the above-mentioned sheet material, and left as it was for 48 hours. Later, the sheet material was removed. As a result, uniform red rust was generated on the entire surface of the test piece.

Example 2 A dispersion prepared by dispersing and dissolving 20 parts of iron powder (average particle size: 3 μm) and 1 part of polyvinyl alcohol in 100 parts of water was prepared, and a thick filter paper (thickness 0.75 mm, commercial product) was prepared. Name: Toyo Filter Paper No. 527) was immersed in this dispersion and dried to prepare a sheet material. Next, the above-mentioned sheet material is SU
S304 Affixed to the test piece surface. Then, 10 parts of ferric chloride, 2 parts of ferric nitrate, and surfactant 0.1
And a solution prepared by dissolving 100 parts of water in the above-mentioned sheet material was spray-sprayed, left as it was for 24 hours, and then the sheet material was removed. As a result, uniform red rust was generated on the entire surface of the test piece.

Example 3 A dispersion prepared by dispersing and dissolving 20 parts of iron powder (average particle size: 1 μm) and 1 part of carboxymethylcellulose in 100 parts of water was prepared, and a polypropylene nonwoven fabric (1.0 mm thick) was prepared.
Was immersed in the dispersion and air-dried to prepare a sheet material. Next, the above-mentioned sheet material was stuck on the surface of the SUS304 test piece. Then, a solution obtained by dissolving 2 parts of ammonium chloride, 10 parts of ferric nitrate, and 0.1 part of a surfactant in 100 parts of water is spray-sprayed on the above-mentioned sheet material and left as it is for 48 hours. After doing
This sheet material was removed. As a result, uniform red rust was generated on the entire surface of the test piece.

Example 4 A dispersion was prepared by dispersing and dissolving 50 parts of iron powder (average particle size: 5 μm) and 2 parts of ethyl cellulose (No. 50 manufactured by Wako Pure Chemical Industries, Ltd.) in 100 parts of ethyl alcohol. A propylene nonwoven fabric (thickness: 1.0 mm) was immersed in the dispersion and air-dried to prepare a sheet material. next,
The above-mentioned sheet material is immersed and moistened in a solution of 5 parts of ferric chloride, 1 part of nitric acid, and 0.1 part of a surfactant in 100 parts of water, and then attached to the surface of a SUS304 test piece. Was. Then, after being left as it is for 24 hours, the sheet material was removed. As a result, uniform red rust was generated on the entire surface of the test piece.

Comparative Example 1 Iron powder (average particle size: 1 μm) was sprayed on the surface of a SUS304 test piece so as to be as uniform as possible, and then a 10% hydrochloric acid aqueous solution was sprayed with such strength that the iron powder was not scattered. It was left for 48 hours. As a result, red rust was generated on the surface of the test piece, but unevenness (a place where no rust was generated) was observed in some places.

Friction test A test piece was prepared by rusting on both front and back surfaces by the method of Example 3 and the method of Comparative Example 1 described above, and this test piece was used as a standard test piece of the Architectural Institute of Japan (material is SUS304).
, The friction coefficient was measured as a base material and side plates. The results are shown in Table 1.

[0020]

[Table 1] In Table 1 described above, in Comparative Example 1, since the surface was in a floating rust state, the rust acted as a roller to promote slipping, and had a lower coefficient of friction than the blank.

[0021]

As described above, according to the rusting treatment method of the present invention, there is provided a process for producing a sheet material in which iron powder is uniformly dispersed, and a method of subjecting the sheet material to a wet treatment with a ferric solution. It consists of two steps, that is, the step of attaching the sheet material on the surface, but since the sheet material can be prepared and stored in advance, it can be performed substantially in one step, and the operation can be performed extremely easily. . That is, the operation of attaching the sheet material to the surface to be treated in a wet state with a ferric solution is, for example,
Even when the surface to be treated is upright, a simple operation of simply spraying the ferric solution with the tape in contact with the sheet material with the tape may be performed.

In addition, in the above-mentioned operation, even when the spray amount is somewhat uneven, or when there is a part where the spraying has been partially forgotten, the ferric solution naturally penetrates into the sheet material, The entire surface in contact with the steel material surface is in a wet state, and the surface to be treated can be uniformly rusted.

Also, the operation of producing a sheet material in which iron powder is uniformly dispersed does not require special raw materials or special processing equipment, and as a whole, the present invention has a very high practical value and a uniform It can perform rusting treatment.

Further, the rust generated by the rusting treatment according to the present invention has a much better adhesion to the steel material surface than the rust generated by leaving it in a natural environment for a long period of time, so that the friction coefficient can be improved. Thus, the joining strength can be increased in joining with high-strength steel bolts.

In addition, according to the present invention, the above-described rusting treatment can be performed in an extremely short time, and therefore, a long standing time is required as in the above-mentioned conventional treatment method. In addition, by adjusting the concentration of the ferric solution, it is possible to control the time until rusting, so it is highly adaptable to the design of construction plans for general steel structures, and its construction and work design It will make a huge contribution to.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C23C 22/00-22/86 F16B 33/06

Claims (1)

(57) [Claims] 1. A rusting treatment method for a steel material surface, wherein a sheet material in which iron powder is uniformly dispersed is wetted with a ferric solution and applied on a surface to be treated.