JP2001082479A - Slide member and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater bearing device excellent in wear resistance to soil and sand mixing and clearance corrosive resistance to sea water, and a sea water pump using the underwater bearing device. SOLUTION: In this slide member, as a first coating, an alloy including Cr, Mo, at least one kind of Si or B, and Ni-Cr-Mo alloy consisting of Ni and unavoidable impurities in the rest are coated on the base material. In addition, as a second coating, an alloy including Cr, Mo, at least one kind of Si or B, and Ni-Cr-Mo alloy consisting of Ni and unavoidable impurities in the rest as a bonding material and a material that has at least one kind of Wc, Cr3C2 as main component, are coated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater bearing device used for a pump or the like used in a seawater environment.
In particular, the present invention relates to an underwater bearing device excellent in corrosion resistance and abrasion resistance suitable for a pump operated in a seawater environment in which earth and sand are mixed, a method of manufacturing the underwater bearing device, and a seawater pump using the underwater bearing device.

[0002]

2. Description of the Related Art Underwater bearings that are directly lubricated with muddy water containing earth and sand are advantageous in terms of simplification of equipment and ease of maintenance because they do not require water injection into the bearings. It is necessary to use a material having excellent wear properties. For such a purpose, a ceramic bearing in which a cemented carbide bearing sleeve and a SiC bearing are combined has been developed, and has a great deal of achievement so far.

However, for application to large underwater bearing parts, both cemented carbide and SiC are technically and economically difficult to integrally produce large parts. Techniques for thermal spray coating of metal composites have been developed.

[0004] The above-mentioned technique is intended to be applied to a bearing device of a river water pump, and includes a general commercial cermet thermal spraying containing Ni and / or Cr as a binder and containing WC and / or Cr ₃ C ₂ as a main component. Material is coated on the sliding surface. However, in the case of the cermet thermal spray coating, the boundary between the coating and the base material serving as the base and the inside of the coating,
There are fine holes that serve as structural gaps. The presence of these gaps does not cause any problem in use in river water, but causes a problem of crevice corrosion when used in seawater for a long time.

[0005] On the other hand, austenitic stainless steel has excellent corrosion resistance in seawater, and is therefore widely used in equipment and devices that are constantly in contact with seawater. As a method for preventing crevice corrosion occurring in this austenitic stainless steel,
A method of embossing a Ni—Cr—Mo alloy on the surface has been developed (Japanese Patent No. 1544046, Japanese Patent No. 1544).
No. 047, Patent No. 1545711, Patent No. 15820
No. 95). However, it cannot be applied to the sliding surface of an underwater bearing which is directly lubricated with muddy water containing earth and sand due to lack of wear resistance.

[0006]

SUMMARY OF THE INVENTION Ni and / or C
r as a binder, WC and / or Cr ₃ C ₂
In general, a cermet sprayed coating mainly composed of: has fine pores at the interface between the coating and the base material, and between the sprayed particles, and these pores are formed through the interface between the particles. They are spatially connected. Therefore, when the cermet spray coating is immersed in seawater for a long time,
Seawater that has intruded into the fine pores in the thermal spray coating is unlikely to be replaced with seawater outside the gap, resulting in crevice corrosion.

FIG. 1 is a schematic cross-sectional view of a sleeve in which a sliding surface is spray-coated on a conventional sliding surface. Sleeve end face 3
In the figure, the fine pores 7-1 at the interface between the coating and the base material
However, since it is exposed to the seawater atmosphere as a gap, when austenitic stainless steel is used as the base material, the portion 8 in contact with the coating of the base material locally causes corrosion, which eventually causes the coating to peel.

Further, as shown in FIG. 1, even when the end face of the coating film is not exposed, the fine pores 6 between the sprayed particles become gaps, and N, which does not have crevice corrosion resistance, is formed.
Portion 9 of the binder of i, Cr, or Ni-Cr alloy is eroded. Alternatively, fine holes 6 between the sprayed particles
As a result, seawater penetrates into fine pores 7-2 existing at the interface between the coating and the base material, and the base material of the portion 10 in contact with the coating causes crevice corrosion.

The present invention has been devised in order to solve the above-mentioned problems, and has an underwater bearing device excellent in wear resistance against sediment contamination and crevice corrosion resistance against seawater, and a seawater pump using the underwater bearing device. Is provided.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has a first film on a surface of a base material as a first film at a boundary portion between the base material and the inside of the film. A sliding member characterized by being coated with a metal or an alloy having no minute pores that cause a cause, and further coated as a second coating with a material composed of a binder and high-hardness particles.

In another aspect, the surface of the base material is
As a first film, a Ni-Cr-Mo-based alloy containing Cr and Mo, containing at least one of Si and B, and the rest consisting of Ni and unavoidable impurities is coated. The coating contains a Ni—Cr—Mo alloy containing Cr and Mo, at least one of Si and B, and the balance Ni and unavoidable impurities as a binder.
It is also possible to coat a material containing at least one of C and Cr ₃ C ₂ as a main component.

[0012] Alternatively, a first film containing Cr and Mo, at least one of Si and B on the surface of the base material, and the remainder consisting of Ni and unavoidable impurities.
-Cr-Mo-based alloy, and as a second coating, a Ni-Cr-Mo-based alloy containing Cr and Mo, the balance being Ni and unavoidable impurities, as a binder;
The coating is made of a material containing at least one of C and Cr ₃ C ₂ as a main component.

[0013] Alternatively, a first coating containing Cr and Mo, at least one of Si and B on the surface of the base material, and the remainder comprising Ni and unavoidable impurities.
-Cr-Mo based alloy, and further containing Ni and / or Cr as a binder as a second coating,
And / or a material mainly composed of Cr ₃ C ₂ is coated.

In these coating steps, the first coating needs to be coated in such a manner that there are no fine pores causing crevice corrosion at the boundary with the base material and inside the coating. Such a coating is performed by a method of powder overlay welding of a powder material by a plasma transferred arc, a TIG using a welding rod.
Or a self-fluxing alloy coating method in which a powder of the material is sprayed or a mixture of the powder of the alloy and an organic binder is applied, and then the material is heated and melted. And so on.

[0015] The coating of the second coating is achieved by an atmospheric plasma spraying method, a reduced pressure plasma spraying method, a high-speed flame spraying method, an ultra-high-speed flame spraying method, an explosion spraying method, etc., which are used for general cermet material spraying. Is done. Or
At least one of Si and B as a binder of the coating material
When an alloy containing a seed is used, a build-up welding method or a self-fluxing alloy coating method can be applied as in the case of coating the first coating.

In the present invention, as schematically shown in FIG. 2, no gap is formed at the interface between the first film coated on the surface of the base material and the base material as in the prior art. . Therefore, even when austenitic stainless steel is used for the base material, crevice corrosion does not occur in the base material near the interface between the coating and the base material.

Fine pores exist at the interface between the first coating and the second coating and inside the second coating, and when immersed in seawater, it becomes an environment in which crevice corrosion occurs. Since the component of the first coating and the component of the binder of the second coating are Ni-Cr-Mo-based alloys having crevice corrosion resistance, crevice corrosion does not occur.

Furthermore, the main component of the second coating is a high-hardness charcoal.
Compound ceramics, WC, Cr₃C ₂At least of
Is also one kind. Therefore, the bearing device of the present invention
SiO whose hardness is lower than chloride₂Contains earth and sand whose main component is
Even when used as an underwater bearing device that lubricates directly with muddy water,
No major damage due to wear.

The N of the binder of the first and second coatings
Si and / or B contained in i-Cr-Mo alloy
Has the effect of lowering the melting point of the alloy and improving the wettability. Therefore, these additions are effective in facilitating the coating work and promoting the densification of the coating. However,
In the case of the binder of the second coating, since the first coating is dense, it is not always necessary to contain Si and / or B to promote the densification of the coating.

Further, in the surface-coated bearing component to which the present invention is applied, the most susceptible to corrosion is the base material at the boundary with the coating. Therefore, when the corrosive environment is not severe, or when the use period is short and a long life is not required, a Ni-Cr-Mo-based alloy having crevice corrosion resistance is used only for the first coating, 2 contains conventional Ni and / or Cr as a binder,
A general commercially available cermet spray coating containing Cr ₃ C ₂ as a main component may be used.

The first coating is formed by overlay welding using a powder of the material or a welding rod as a raw material.
A self-fluxing alloy coating method in which a powder of the material is sprayed or a mixture of the powder of the material and an organic binder is applied, and then the Ni-Cr-Mo alloy component of the material is heated and melted. May be formed by coating.

Further, the first coating and the second coating may be formed by cladding welding using powder of the material or a welding rod as a raw material.

Further, the first coating is sprayed with a powder of the material, or a mixture of the powder of the material and an organic binder is applied, and then the Ni—Cr—Mo alloy component of the material is applied. The coating is formed by a self-fluxing alloy coating method of heating and melting,
The second coating may be formed by overlay welding using a powder of the material or a welding rod as a raw material.

Further, the first coating is sprayed with a powder of the material, or a mixture of the powder of the material and an organic binder is applied, and then the material is heated and melted. The second coating is sprayed with a powder of the material, or a mixture of the powder of the material and an organic binder is applied, and then the Ni-Cr-M
The coating may be formed by a self-fluxing alloy coating method of heating and melting the o-based alloy component.

It is preferable that the above-mentioned sliding member or the sliding member manufactured by the above-mentioned method is used for an underwater bearing device.
In particular, it is suitable for use in a bearing device such as a pump used in a seawater environment.

[0026]

[Example] SUS30 of austenitic stainless steel
4 as material, outer diameter φ62.6mm, inner diameter φ51mm,
A cylindrical member having a length of 65 mm was produced. On this outer peripheral surface,
30% Cr (% by weight, hereinafter the same) as the first coating,
A Ni-Cr-Mo-based alloy powder containing 10% Mo and 1% Si and the balance consisting of Ni and inevitable impurities was coated to a thickness of 1.5 mm by a plasma transferred arc welding method. Next, the surface layer was processed and removed by machining to finish the outer diameter to 64.6 mm.

As the second film, 30% Cr, 10% M
o A Ni-Cr-Mo alloy containing 1% Si and the balance consisting of Ni and unavoidable impurities is used as a binder, and a powder material comprising 25% of the binder and 75% of WC is formed by a high-speed flame spraying method. It was coated to a thickness of 0.5 mm. Next, by machining, the surface layer is processed and removed, and the inner diameter and the length are finished, and a cylindrical member having an outer diameter of 65 mm, an inner diameter of 53 mm, and a length of 63 mm and having a two-layer coating on an outer peripheral portion is formed. Produced.

In the above embodiment, as the base material of the base material,
Although SUS304 of austenitic stainless steel was used, any material that can be used in seawater may be used.
It does not limit the type of the base material.

In the above-described embodiment, the plasma-transferred arc welding method was used as the first coating method. However, pores causing crevice corrosion were formed at the boundary between the coating and the base material and inside the coating. Any method that does not generate
The method is not limited. However, the plasma transferred arc welding method and the TIG welding method are desirable from the viewpoint of long-term reliability of the coating.

In the above embodiment, the high-speed flame spraying method is used as the method for coating the second film. However, any method capable of spraying the cermet material may be used, and the method is not limited. In addition, atmospheric plasma spraying, low-pressure plasma spraying, ultra-high-speed flame spraying, explosive spraying, etc. can be used, but low-pressure plasma spraying, high-speed flame spraying, ultra-high It is desirable to use flame spraying or explosive spraying.

Further, in the above embodiment, a material whose main component is WC is coated as the second coating, but this main component material may be any material having a higher hardness (Hv 1000 or more) than SiO ₂ which is a main component of earth and sand. , WC. Other carbide ceramics such as Cr ₃ C ₂ , NbC, Ti
C, or a mixture of carbide ceramics containing two or more of WC, Cr ₃ C ₂ , NbC, and TiC may be used. However, WC has high reliability as a wear-resistant material and has a long track record.
And / or Cr ₃ C ₂ is preferably used.

In the above embodiment, the material of the first film and the binder of the second film are 30% Cr, 10%
Although a Ni—Cr—Mo-based alloy containing Mo and 1% Si and the balance of Ni and unavoidable impurities was used, the contents of Cr and Mo are not limited thereto. It is sufficient that the above alloy has crevice corrosion resistance, and any Cr and Mo can be contained within the range.

Similarly, the content of Si is not limited to the examples. Any function that lowers the melting point of the alloy and improves the wettability may be sufficient, and may include B or both Si and B. However, since these elements may deteriorate the crevice corrosion resistance, the upper limit of the addition amount is 4%.
It is desirable that Further, as a binder for the second coating, an action of lowering the melting point of the alloy and improving the wettability is not necessary, so that an alloy made of Ni, Cr, and Mo, which does not necessarily contain Si as in the example, is used. There may be.

FIG. 3 is a schematic cross-sectional view of a bearing device of the present invention in which the cylindrical member is used as a bearing sleeve and is combined with a SiC bearing.

[0035]

As described above, according to the present invention, it is possible to obtain a sliding member excellent in abrasion resistance to earth and sand mixing and crevice corrosion resistance to seawater, and an underwater bearing device using the same. As a result, stable operation of a large-sized pump that handles seawater containing earth and sand becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic view of crevice corrosion occurrence in the prior art.

FIG. 2 is a schematic view of a sliding surface of a sliding member in the bearing device of the present invention.

FIG. 3 is a schematic view of the bearing device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Outer peripheral surface of sleeve 2 Inner peripheral surface of sleeve 3 End surface of sleeve 4 Thermal spray coating 5 Base material 6 Void inside coating 7-1, 7-2 Void at interface between coating and base material 8 Mother generated at end surface Crevice corrosion portion of the material 9 Crevice corrosion portion inside the coating formed by seawater entering the thermal spray coating 10 Crevice corrosion portion of the base material generated by seawater entering the thermal spray coating 11 First coating 12 Second coating 13 Sleeve 14 Bearing 15 Shaft sleeve 16 Bearing case 17 Sleeve fixing ring

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hirokazu Takayama 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 3J011 AA20 BA02 CA05 DA02 QA03 SB12 SB14 SB15 SB20 4K018 BA04 BA09 BA11 BD04 BD09 JA22 KA02 KA58 4K031 AA02 AA08 AB03 AB08 AB09 BA05 CB22 CB23 CB29 CB30 CB45

Claims (6)

[Claims] 1. A surface of a base material is coated as a first coating with a metal or an alloy having no fine pores causing crevice corrosion at a boundary portion with the base material and inside the coating. 2. A sliding member, characterized in that the coating of (2) is coated with a material comprising a binder and high-hardness particles. 2. A Ni—Cr—Mo alloy containing Cr and Mo as a first film, at least one of Si and B on the surface of the base material, and the balance consisting of Ni and unavoidable impurities. And Cr and Mo as a second coating.
i, B, and at least one of WC and Cr ₃ C ₂ as a main component containing a Ni—Cr—Mo alloy containing the remainder of Ni and unavoidable impurities as a binder. A sliding member coated with a material as described above. 3. A Ni—Cr—Mo alloy containing Cr and Mo as a first film, at least one of Si and B, and the balance of Ni and unavoidable impurities on the surface of the base material. covering the system alloy, furthermore, a second coating, Cr, containing Mo, include Ni-Cr-Mo alloy balance being Ni and inevitable impurities as a binder, WC, of the _Cr 3 _{C 2} A sliding member coated with a material containing at least one of the following as a main component. 4. A Ni—Cr—Mo alloy containing Cr and Mo as a first coating on the surface of the base material, containing at least one of Si and B, and the balance consisting of Ni and unavoidable impurities. A sliding member characterized by being coated with a base alloy and further coated as a second coating with a material containing Ni and / or Cr as a binder and containing WC and / or Cr ₃ C ₂ as a main component. . 5. The method for manufacturing a sliding member according to claim 1, wherein the first coating is formed by overlay welding using a powder of the material or a welding rod as a material. A method for manufacturing a sliding member, wherein the second coating is formed by thermal spraying using powder of the material as a raw material. 6. The method for manufacturing a sliding member according to claim 1, wherein the first coating is formed by thermal spraying a powder of the material, or applying a powder of the material to an organic binder. A coating is formed by applying a mixture, and thereafter forming a coating by a self-fluxing alloy coating method in which the material is heated and melted, and forming the second coating by a thermal spraying method using a powder of the material. A method for manufacturing a moving member.