JPS5910372A - Method for preventing corrosion of stainless steel material - Google Patents

Abstract

PURPOSE:To prevent thoroughly crevis corrosion under corrosive environment in the stage of coating a strippable paint on a stainless steel material, by applying positive corrosion prevention in the end part of a painted film. CONSTITUTION:A corrosion preventive agent 2 having self-adhesiveness is beforehand adhered in the coating end part of a stainless steel material 1 prior to coating of a strippable paint thereon, and in succession, the strippable paint is coated thereon so as to overlap on said agent to form a painted film 3. The crevis corrosion in the end part of the film 3 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing corrosion of stainless steel materials, and particularly to a coating method suitable for preventing crevice corrosion at coating edges where crevices are likely to occur.

A method for preventing crevice corrosion at the edge of a coating film is disclosed in Japanese Patent Publication No. 1984-84669. Korekeke is characterized by applying crevice corrosion prevention means to the edges of the coating when applying a releasable paint. Specifically, it attempts to prevent crevice corrosion by using ordinary paint or adhesive tape to remove the edges of the coating without leaving any gaps.

The present invention is concerned with the treatment of the edges of a coating film when applying a releasable paint to prevent the formation of gaps and at the same time actively prevents corrosion at the edges to prevent crevice corrosion.

Since stainless steel has a protective film on its surface, it is often used unpainted as it is rust-resistant, but in environments containing chlorine such as seawater, the protective film dissolves and the base metal corrodes. There is.

As a countermeasure to this problem, there is a method of painting the surface of the stainless steel material to prevent corrosive substances from coming into direct contact with the surface of the steel material.

However, inspection of the base material after painting (e.g. inspection of welded parts, etc.)
may be necessary. When a normal paint is applied, a blast treatment or the like is generally effective in removing the paint film. However, this method is not preferred because it may damage the surface of the stainless steel material under the coating, destroy the protective film on the surface, and make the base metal more susceptible to corrosion. In such cases, it may be convenient to use a releasable paint, whose paint film is relatively easy to remove, instead of a regular paint. However, because of its purpose, this paint has a slightly weak adhesive force with the object being coated, and because the paint generally has poor adhesion to stainless steel materials, the edges of the paint film tend to peel off and the bond between the paint and the base material is low. There may also be gaps between the two. Stainless steel materials are prone to corrosion (crevice corrosion) on the metal surface in such minute gaps.

Japanese Patent Publication No. 56-84669 describes a coating method that prevents crevice corrosion by not creating gaps at the edges of the coating film.

The present invention describes a method that prevents the occurrence of crevices due to peeling of the edges of the coating and at the same time actively prevents corrosion, thereby preventing crevice corrosion even if peeling occurs.

The present invention will be explained below with reference to the drawings.

■ Figure 1 shows an example of the coating method. When applying a removable paint (for example, 8US to Kurivac CA-25 manufactured by Daito Kogyo Co., Ltd.) to the stainless steel material (1) to be painted, apply an adhesive corrosion inhibitor (2
) (for example, the crevice corrosion inhibitor shown in Japanese Unexamined Patent Publication No. 53-44443), and then (2)
Apply a releasable paint so as to overlap it to form the coating film (3). This prevents crevice corrosion at the edges of the coating (3).

Color) In the coating system shown in A and FIG. 1, the edges of the coating film (3) are covered with adhesive tape (4) as shown in FIG.

(Also, as shown in Figure 3, after applying the releasable paint (5) to the stainless steel material (1), apply the adhesive corrosion inhibitor (6) to overlap the edge of the paint film. Prevents crevice corrosion at the edges of the paint film.

0 In the coating system shown in C and FIG. 3 above, the end of the adhesive corrosion inhibitor (6) is covered with adhesive tape (7) as shown in FIG.

■ The painting methods shown in A, B, C, and D are based on the target force
Although stainless steel pipes may be used, such as stainless steel plates or pipes, the following describes a coating method when a cap made of polyethylene or stainless steel is attached to protect the inside of the pipe. As shown in Figure 5, when attaching the cap (11) to the tube (8), leave a gap of 1 between (8) and (11).
A river arises. This gap is filled with an adhesive corrosion inhibitor (9), a removable paint (10) is applied so as to overlap this, and an adhesive tape is applied to cover the ends of the paint film and the cap. At this time, if necessary, paint the other end of the tube using the same procedure. Further, similar painting is no longer necessary where the other end is sealed.

According to the present invention, stainless steel materials must be coated with a paint system that is less likely to cause crevices, and that the edges should be aggressively coated to prevent crevice corrosion that may occur at the edges of the coating film when applying a release paint. Corrosion protection can prevent corrosion even in corrosive environments, which has the effect of expanding the range of uses for stainless steel materials.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views showing embodiments of the present invention.

Claims (1)

[Claims] 1. In the method of applying a releasable paint to stainless steel material, an adhesive anticorrosive agent for stainless steel is adhered to the edge of the coating, and a releasable paint is applied on top of it. Features a corrosion prevention method for stainless steel materials. 2. The method for preventing corrosion of stainless steel materials according to claim 1, which comprises covering the edges of the coating film with an adhesive anticorrosive agent. 3. The method for preventing corrosion of stainless steel material according to claim 1, which comprises covering the edge of the coating film or the edge of the adhesive anticorrosive agent with an adhesive tape.