JPH0860331A - Anticorrosion treatment method for hydraulic equipment components - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide excellent wear resistance and corrosion resistance by covering the bond coat layer exposed at the thermal spray boundary of hydraulic equipment components with a film. [Structure] The low temperature sprayed layer 3 is formed on the processing target portion of the guide vane 1.
The bond coat layer 3a and the middle coat layer 3b are made of Ni-Al and 13Cr steel, respectively.
c are each made of stainless steel. Further, the bond coat layer 3a exposed at the thermal spray boundary is subjected to high-speed gas flame spraying, for example, diamond jet spraying to form CrC.
The cermet material is sprayed to form a high-speed gas flame sprayed coating layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for anticorrosion treatment of hydraulic equipment members.

[0002]

2. Description of the Related Art Conventionally, members used in hydraulic power equipment may be extensively corroded by the water used. As a countermeasure against this corrosion, stainless steel, which has excellent corrosion resistance by low temperature gas spraying with little deformation due to heat, is used as the top coat.
A thick film is formed as a sheet. However, in order to improve the adhesion between the thermal spray coating and the base material, the thermal spray boundary is subjected to thermal spraying called a bond coat at the same time. This bond coat layer has a portion exposed to the thermal spray boundary, and the bond coat material is vulnerable to corrosion, and the bond coat layer is selectively corroded and peeling occurs. As a countermeasure against this, an anticorrosion treatment method is used in combination with the coating of water resistant paint or the coating of epoxy resin material.

On the other hand, in high-speed gas flame spraying, 13
It is known that the sprayed particles collide with the base material at a sound velocity of 80 m / sec, so that a sprayed film with extremely high density and high adhesion can be obtained as compared with low temperature gas spraying. The maximum thickness is about 0.3 mm, and thermal spraying of thick film is impossible.

[0004]

Although the conventional anticorrosion method is excellent in corrosion resistance, the coated epoxy resin material is prematurely worn or peeled off due to abrasion due to earth and sand or cavitation. Since the coating film peels off early in this way, the bond coat layer at the thermal spray boundary is exposed, and the effect cannot be maintained for a long time.

An object of the present invention is to provide a method for treating a corrosion protection member for hydraulic equipment, which is capable of covering the bond coat layer exposed at the thermal spray boundary with a coating and imparting excellent wear resistance and corrosion resistance.

[0006]

In order to achieve the above object, a method of anticorrosion treatment according to the present invention is that a surface of a member is subjected to low temperature gas spraying, and a surface of a base material boundary portion of the sprayed layer is a thin film high-speed gas flame. It is characterized by being covered with a thermal spray coating.

[0007]

Operation: There are two methods for preventing the peeling of the bond coat material due to corrosion. One is to cut off the contact with water, which is the cause of corrosion, and the other is to provide sufficient corrosion resistance. The present invention focuses on the former case of breaking the contact with water, and the exposed thermal spray boundary portion of the bond coat layer is covered with a dense thermal spray coating. That is, coating is performed using high-speed gas flame spraying, which provides high adhesion even without a bond coat layer. This completely prevents contact with water and prevents corrosion. On the other hand, it is possible to remarkably improve the wear resistance of the coating layer by using a high wear resistance material that cannot be applied by high temperature gas flame spraying with low temperature gas spraying, such as a cermet material made of a mixed powder of ceramics and metal. You can Further, these constructions are easy to carry out locally, and repairs can be completed in a short period of time.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows a guide vane 1 which is a hydraulic equipment member. The guide vane 1 is subjected to anticorrosion treatment because the part in contact with water is locally corroded. The low temperature sprayed layer 3 as shown in FIG.
The bond coat layer 3a and the middle coat layer 3b are made of Ni-Al and 13Cr steel, respectively.
c are each made of stainless steel. The low temperature gas sprayed layer 3 is formed to have a film thickness of 5 mm in all layers. The bond coat layer 3a exposed at the thermal spray boundary portion is sprayed by high-speed gas flame spraying, for example, 20 mm from the thermal spray boundary portion to the thermal spray layer side by using, for example, a diamond jet spraying method, to form the high-speed gas flame spray coating layer 4. As this material, a CrC cermet material having excellent wear resistance is used. Further, a resin is applied on the high-speed gas flame spray coating layer 4 to complete the coating. (Experimental Example 1) As a result of the blast erosion test of the test pieces manufactured by the conventional method and the method of the present invention, the coating film was worn after 3 seconds in both the conventional method and the method of the present invention.
After 80 seconds, the test piece of the conventional method is remarkably worn on the base material and the low temperature gas sprayed layer, whereas the test piece of the method of the present invention is not worn due to the dense coating by high-speed gas flame spraying, It was confirmed to have excellent wear resistance.

Further, as a result of performing a salt spray test of the test pieces of the conventional method and the method of the present invention in which the coating film is abraded by the blast erosion test, it was found that the conventional method was within 72 hours in the vicinity of the bond coat layer which was the thermal spray boundary. While rusting was observed, the test piece manufactured by the method of the present invention did not show rusting even after 144 hours, and it was confirmed that the test piece had a corrosion resistance more than double. As described above, according to the present invention, compared with the conventional method, the life of the hydraulic equipment member can be remarkably improved.

[0010]

As described above, in the present invention, since the surface of the base material boundary portion of the sprayed layer is covered with the thin film of high-speed gas flame spray coating, the corrosive bond coat layer does not come into contact with water, and low temperature gas spraying is performed. It is possible to prevent peeling of layers. Therefore, according to the present invention, it is possible to impart excellent wear resistance and corrosion resistance to the hydraulic equipment member, and it is possible to significantly extend the life of the hydraulic equipment.

[Brief description of drawings]

FIG. 1 is a sectional view of a guide vane to which the anticorrosion treatment method according to the present invention is applied.

FIG. 2 is a perspective view of a guide vane according to the present invention.

[Explanation of Codes] 1 ... Guide vane 2 ... Processing unit 3
... Low temperature gas sprayed layer 3a ... Bond coat layer 3b ... Middle coat layer 3
c ... Top coat layer 4 ... High-speed gas flame sprayed coating layer 5 ... Coating film

Claims (1)

[Claims] 1. To prevent pitting corrosion of hydraulic equipment members,
A method for anticorrosion treatment of a hydraulic equipment member, characterized in that the surface layer of the member is subjected to low temperature gas spraying, and the base material boundary surface of the sprayed layer is covered with a thin high-speed gas flame spray coating.