JP2004027289A - Self fluxing alloy thermal spray material containing ceramic particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal sprayed layer excellent in cavitation erosion resistance and slurry erosion resistance. <P>SOLUTION: A self fluxing alloy thermal spray material containing a ceramic particle is made by mixing and flocculating at least one of ceramic powder 11 selected from the group consisting of carbide, oxide, nitride or boride, and at least one of self fluxing alloy powder 12 selected from the group consisting of nickel base self fluxing alloy powder, cobalt base self fluxing alloy powder or iron base self fluxing alloy powder, and the self fluxing alloy thermal spray material is made by the granular object 10 which has a bigger average secondary particle size than an average primary particle size of the above powder, wherein the average secondary particle size is 15-250 μm. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a ceramic particle-containing self-fluxing alloy sprayed material, and more particularly, to a turbomachine such as a pump, a water turbine, and a turbine, and in particular, a blade that is required to have cavitation erosion resistance and slurry erosion resistance on the surface of a metal substrate. A ceramic-containing self-fluxing alloy spray material suitable for applying a wear-resistant coating layer on the surface of a metal substrate such as a car, a casing, a blade, a bearing or the like where wear resistance is required. The present invention relates to a sprayed impeller and a fluid machine having the impeller.
[0002]
[Prior art]
In turbo machines such as pumps and water turbines, there is a problem of material erosion due to slurry erosion caused by mixing of earth and sand into running water and cavitation erosion caused by partial load operation. Particularly, in an impeller, a casing, and the like, since slurry erosion is generated simultaneously with cavitation erosion, high toughness and excellent slurry erosion resistance and cavitation erosion resistance are required. In the impeller and casing, a wear-resistant sprayed coating can be applied in advance to a portion where damage is predicted to occur. In addition, after a certain operation, by repairing the portion damaged by the slurry erosion and the cavitation erosion by thermal spraying, it is possible to extend the life of equipment such as a pump and a water wheel.
[0003]
Many methods have been proposed for the thermal spraying method and occupy an important position in the surface modification technology. Among them, the spray melting method heats the self-fluxing alloy powder sprayed film by flame spraying etc. to the molten state, reduces the pores in the film, furthermore, the bond between the sprayed particles and the adhesion strength with the substrate In this respect, since this is the most effective thermal spraying method, it is widely applied to members requiring wear resistance. For mechanical parts used in an environment where earth and sand wear occurs, a thermal spray melting method using a thermal spray powder obtained by mixing a carbide powder such as tungsten and a self-fluxing alloy powder is generally applied. In a machine in which earth and sand wear occurs, when the particle size of the earth and sand is 0.1 mm or more, tungsten carbide particles of about 0.1 mm to several mm are used, thereby achieving a predetermined purpose.
[0004]
Recently, a nickel (Ni) -based alloy or cobalt (Co) -based alloy sprayed film in which carbide particles of several microns are dispersed has been applied to a wear-resistant member by a technique using high-speed flame spraying (HVOF, HVAF, etc.). The high-speed flame sprayed film is applied to a water wheel or an impeller for a pump, caging, and the like, and has been confirmed to exhibit excellent characteristics of slurry erosion resistance. However, in high-speed flame spraying, a method of forming a sprayed film using a powder obtained by granulating carbide particles and a Ni-based or Co-based alloy powder on the order of several microns, or a powder obtained by granulating, sintering and pulverizing is used as a raw material. is there. In this method, since partial melting is performed, numerous voids exist in the sprayed layer, and the adhesion between particles is insufficient. Therefore, the high-speed flame-sprayed film has weak characteristics against cavitation erosion, and is difficult to apply to a location where cavitation occurs.
[0005]
Since slurry erosion occurs simultaneously with cavitation erosion in a water wheel or a pump, there is an urgent need to develop a sprayed coating having excellent erosion resistance as well as slurry erosion resistance. This self-fluxing alloy was used because the self-fluxing alloy spray coating reduces the pores in the coating by fusing treatment of heating to a molten state, and further improves the bonding between the sprayed particles and the adhesion strength to the substrate. The thermal spray melting method is widely applied to members requiring slurry erosion resistance and cavitation erosion resistance.
[0006]
FIGS. 1 and 2 show conceptual views of conventional thermal spraying material powder and thermal spraying by the flame spraying method, respectively. In a machine in which earth and sand wear occurs, since the average particle diameter of earth and sand is 0.1 mm or more, tungsten carbide particles having a particle diameter of about 0.1 mm to several millimeters are used as ceramic powder to achieve a predetermined purpose. I have. In river water mixed with relatively small sand having an average particle diameter of 0.1 mm or less, a sprayed film in which tungsten carbide having an average particle diameter of 60 to 125 μm is dispersed is applied to an impeller and a casing. As shown in FIG. 1, a tungsten carbide powder 1 having a particle size of 45 μm to 125 μm and a self-fluxing alloy powder 2 having a particle size of 15 μm to 125 μm were simply mixed into the thermal spray material used for thermal spray melting. Thermal spray powder 3 is used. In the flame spraying method, as shown in FIG. 2, a spraying material powder 3 composed of a tungsten carbide powder 1 and a self-fluxing alloy powder 2 is supplied from a spraying material supply nozzle 5, and a spraying material powder exiting from the supply nozzle. Is sprayed onto the surface of the base material B with a high-temperature combustion gas 7 from a gas nozzle 6 to melt the self-fluxing alloy powder and fuse it as a sprayed layer 4, and the tungsten carbide particles 1, which are ceramics, in the sprayed layer 4. I try to take in.
[0007]
The inventors of the present invention performed flame spraying using a sprayed powder obtained by mixing tungsten carbide powder having various particle diameters and a self-fluxing alloy powder, and found that when the particle diameter is 100 μm or less, scattering of tungsten carbide particles occurs. Observed. In particular, it has been found that when the particle size is 60 μm or less, the scattering of tungsten carbide particles becomes remarkable, and the thermal spraying efficiency is extremely reduced. Further, in the experiments of the inventors, using a thermal spray powder obtained by mixing a tungsten carbide powder and a self-fluxing alloy powder, a thermal spray material produced by a thermal spray melting method produces a thermal spray layer in which tungsten carbide is uniformly dispersed. However, it is difficult to obtain sufficient cavitation erosion resistance.
[0008]
[Problems to be solved by the invention]
The present inventors have conducted intensive studies to solve the above problems, and as a result, agglomerated average powders by granulating a ceramic powder such as tungsten carbide and a nickel-based self-fluxing alloy powder via a binder. It has been found that by using a granular material having a secondary particle diameter of 15 to 125 μm, the tungsten carbide powder is prevented from scattering during flame spraying, and the spraying efficiency is improved. In addition, it was confirmed that by using the powder composed of the granular material, a sprayed film in which tungsten carbide was uniformly dispersed in the sprayed layer could be formed, and a sprayed layer having excellent slurry erosion resistance and cavitation erosion resistance was formed. I found that I can do it.
[0009]
Therefore, the problem to be solved by the present invention is to mix a ceramic powder of various particle sizes and a self-fluxing alloy powder and granulate or sinter and pulverize them to obtain a granular material, thereby obtaining a hard material at the time of thermal spraying. An object of the present invention is to provide a thermal spray material in which scattering of ceramic powder is reduced.
Another object to be solved by the present invention is to reduce the scattering of the hard ceramic powder during the thermal spraying process by optimizing the size of the granular material of the ceramic powder and the self-fluxing alloy powder. Is to provide the material.
Another object to be solved by the present application is to provide a rotary member sprayed using the above-described thermal spray material and a fluid machine including the rotary member.
[0010]
[Means for Solving the Problems]
The self-fluxing alloy sprayed material containing ceramic particles according to one aspect of the present invention includes at least one ceramic powder selected from the group consisting of carbides, oxides, nitrides, and borides, a nickel-based self-fluxing alloy powder, and a cobalt-based self-fluxing alloy. A particulate material having a mean secondary particle size larger than the mean primary particle size of the powder by mixing and aggregating with at least one type of self-fluxing alloy powder selected from the group consisting of a fusible alloy and an iron-based self-fluxing alloy powder; Wherein the average secondary particle size of the granular material is 15 to 250 μm.
[0011]
In the ceramic particle-containing self-fluxing alloy sprayed material, when the average primary particle size of the ceramic powder is R1 and the average primary particle size of the self-fluxing alloy powder is R2, R2 / R1 may be 20 or less. The ceramic powder and the self-fluxing alloy may have an average primary particle diameter of 1 to 60 μm and 1 to 60 μm, respectively. Further, the ceramic powder may be at least one kind of carbide powder selected from the group consisting of tungsten carbide, chromium carbide, and titanium carbide.
Another invention of the present application is an impeller provided with a hub and a plurality of blades attached circumferentially around the hub, wherein at least a part of the surface of the impeller has the ceramic particles. It is formed by spraying with a contained self-fluxing alloy spray material.
Another invention of the present application is directed to an impeller having a hub, a plurality of wings circumferentially mounted around the hub, and a casing defining a chamber for rotatably housing the impeller. , At least a portion of the surface of the impeller and / or at least a portion of the inner surface of the casing are sprayed with the ceramic particle-containing self-fluxing alloy spray material.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described.
In the present embodiment, first, for example, a ceramic powder 11 which is a carbide such as tungsten carbide (WC or W ₂ C), titanium carbide (TiC), and chromium carbide (Cr ₂ C ₃ ), and a nickel-based self-fluxing alloy The powder 12 is agglomerated by granulation via a binder by a known granulation method to form a granular material 10 as shown in FIG. 3A, and the thermal spray material of the present embodiment is formed by the granular material 10. I do. The average primary particle size of the ceramic powder such as WC and W ₂ C and the nickel-based self-fluxing alloy powder are each preferably in the range of 1 μm to 60 μm, most preferably in the range of 5 μm to 30 μm. The reason is that if the particle size is less than 1 μm, oxidation of the particles during thermal spraying becomes a problem. On the other hand, if the particle size exceeds 60 μm, granulation becomes difficult. When the average primary particle size of the ceramic powder is R1 and the average primary particle size of the self-fluxing alloy powder is R2, R2 / R1 is preferably 0.1 or more and 20 or less, most preferably 0.1 or more. 10 or less. The reason is that when R2 / R1 exceeds 20, the particles 12 of each self-fluxing alloy are covered with the fine ceramic particles 11 as shown in FIG. It is because it becomes easy to do. Further, the reason why the diameter is set to 0.1 or more is that when the ceramic particles have a size of 1 μm to 60 μm as described above, the practically usable particle size of the self-fluxing alloy is about 1/10 of the diameter of the ceramic particles. Because until.
[0013]
Ceramics are not limited to the above-mentioned carbides. For example, oxides such as aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ), nitrides such as boron nitride (BN), or For example, a boride such as titanium boride (TiB) may be used. Further, the carbides, oxides, nitrides, and borides may be used alone or in any combination thereof. The average primary particle size of these oxides, nitrides or borides may be in the same range as described above. Examples of the nickel-based self-fluxing alloy include, for example, Ni-B-Si and Ni-P. As the self-fluxing alloy (self-fusing alloy having a low melting point), in addition to the nickel-based self-fluxing alloy powder, a cobalt-based self-fluxing alloy such as Co-B-Si or Co-P, or FeSi or Fe- Iron-based self-fluxing alloys such as B-Si and Fe-P may be used. These self-fluxing alloys may be used alone or in any combination thereof.
[0014]
As a method of forming the ceramic powder and the self-fluxing alloy powder into a granular material, in addition to the above-described known granulation method, a method in which the powder is solidified to a desired size, sintered, and then pulverized may be used. The average particle size, ie the average secondary particle size, of the granules is preferably in the range from 15 μm to 250 μm, most preferably in the range from 45 μm to 125 μm. The reason is that if the secondary particle size is less than 15 μm, the thermal spraying efficiency is reduced, and if the secondary particle size exceeds 250 μm, it becomes difficult to perform thermal spraying using a normal flame spray gun. .
[0015]
[Example 1]
As a ceramic powder, a tungsten carbide (WC) powder having an average primary particle size of 5 μm was used. As a nickel-based alloy powder, which is a kind of self-fluxing alloy, a commercially available Colmonoy No. 1 powder was used. Four equivalents of powder were used. The average primary particle size of the powder was 20 μm or less. These powders were mixed to produce a thermal spray material consisting of granules having an average secondary particle size of 45 to 125 μm by a known granulation method.
The results of observing the sprayed material according to Example 1 and the sprayed material of the mixed powder type of the conventional example with an operation type electron microscope are as shown in the micrograph shown in the upper part of FIG. In addition, the results of observing the sprayed layer when the thermal spraying process is performed using the thermal sprayed material according to Example 1 and the thermal sprayed layer when the thermal spraying process is performed using the conventional thermal sprayed material are observed with the microscope. FIG. 4 shows a micrograph at the bottom. As is clear from these photographs, the cross-section of the sprayed layer of the conventional example has a structure having many relatively large voids. On the other hand, the cross section of the sprayed layer of the present invention is a dense sprayed layer with few voids. Tungsten carbide is the white spot on the thermal spray section, and the surrounding area is the matrix phase of the self-fluxing alloy. In the case of the conventional example, the size of the tungsten carbide particles is several tens to 100 μm, and it is observed that the tungsten carbide particles are unevenly dispersed. It can be seen that in the thermal spray material according to Example 1, a thermal spray layer in which tungsten carbide having an average particle diameter of 5 μm was uniformly dispersed was obtained. The cavitation erosion resistance of the thermal sprayed material according to Example 1 was four times or more that of the base material CA6NM.
[0016]
[Example 2]
As a ceramic powder, a tungsten carbide (WC) powder having an average primary particle diameter of 5 μm was used. As a cobalt-based alloy powder, which is a kind of self-fluxing alloy, commercially available Stellite No. 1 powder was used. One equivalent of powder was used. The average primary particle size of the powder was 20 μm or less. These powders were mixed to produce a thermal spray material consisting of granules having an average secondary particle size of 45 to 125 μm by a known granulation method.
Observation results of the thermal spray material according to Example 2 and the thermal spray material of the Co-based self-fluxing alloy powder type of the conventional example by an operation type electron microscope are as shown in a micrograph shown in the upper part of FIG. Further, the results of observing the results of observation of the sprayed layer when the thermal spraying process was performed using the thermal sprayed material according to Example 2 and the thermal sprayed layer when the thermal spraying process was performed using the conventional thermal sprayed material with the above microscope are shown. The result is as shown in the micrograph at the bottom of FIG.
As is clear from this micrograph, the cross section of the conventional sprayed layer has a structure having relatively large voids. On the other hand, the cross section of the thermal sprayed layer according to Example 2 is a dense thermal sprayed layer having few voids. Tungsten carbide is the white spot on the thermal spray section, and the surrounding area is the matrix phase of the self-fluxing alloy. In the case of the conventional example, the size of the tungsten carbide particles is from several tens to 100 μm, and it is observed that the tungsten carbide particles are unevenly dispersed. It can be seen that in the present invention, a sprayed layer in which tungsten carbide having an average particle size of 5 μm is uniformly dispersed is obtained. The cavitation erosion resistance of the thermal sprayed material of Example 2 also exhibited a property four times or more that of the base material CA6NM.
[0017]
The ceramic particle-containing self-fluxing alloy sprayed material produced as described above is sprayed on the surface of the base material by a flame spraying method to form a wear-resistant film on the base material. Examples of the substrate on which the abrasion-resistant film is formed include members of a rotating machine such as a pump, a water wheel, and a compressor, and more specifically, a blade that requires sand erosion resistance or slurry erosion resistance. Examples include cars, casings, blades, bearings and seals. By forming an abrasion-resistant film on such a substrate, the abrasion resistance of such a substrate is improved, and the life of a machine using such a substrate, for example, a pump, a water wheel, a compressor, etc. Can be extended. More specifically, as shown in FIG. 6, the impeller 30 has a hub 32 in which a shaft hole 31 for receiving a rotation shaft is formed, and a disc-shaped radially outwardly extending radially outward from the hub 32. A main plate 33, an annular side plate 34 separated from the main plate 33 in the axial direction (vertical direction in FIG. 6), and a circumferential direction between the main plate 33 and the side plate 34 (a circumference around the axis O-O of the shaft hole). Direction), and is formed along with a side plate and a main plate and a plurality of wings 35 formed integrally with the side plate and the main plate by being curved along a desired curved surface. Flow path 36 is defined. A radially inner portion 37 of the flow path 36 serves as an inlet, and a radially outer portion 38 serves as an outlet. Further, the annular side plate 34 has a portion 34a extending in the circumferential direction and extending in the axial direction, and a portion 34b extending in the radial direction, and defines the inlet 39 of the impeller 30 by the axially extending portion 34a. . When the impeller 30 is rotated to send out fluid, for example, when the impeller is rotated in water containing earth and sand, particles of the earth and sand in the water cause the surface of the impeller 30, particularly the flow path 36 in the impeller 30. Are rubbed against the inner surface 41 of the main plate 33, the inner surface 42 of the side plate 34, and both surfaces of the blade 35, that is, the pressure surface 43 and the negative pressure surface 44, and these surfaces are extremely worn by friction.
[0018]
Therefore, desired surfaces among the inner surfaces 41 and 42 defining the flow path 36 of the impeller 30, the pressure surface 43 and the suction surface 44, the inner surface 45 of the inlet 39, the outer surface 46 of the side plate 34, and the back surface 47 of the main plate 33. For example, the outer peripheral surface 46 (area A1) of the side plate 34 and the surface defining the flow path 36 defined by the main plate 33, the side plate 34, and the blades 35 and within a predetermined range on the outer peripheral side of the impeller (FIG. 6) the surface belonging to the region A2 in the area surrounded by the circle of the circle and the radius r of the radius r _1), it is sprayed ceramic particles containing self-fluxing alloy sprayed material according to the invention in a high speed flame spraying method.
[0019]
The impeller 30 of the present invention surface-treated with the ceramic particle-containing self-fluxing alloy spraying material by the high-speed flame spraying method as described above is used for a fluid machine such as a water wheel or a pump. In FIG. 7, a vertical pump 50 is shown in cross section as an example of such a fluid machine. In the figure, a pump 50 includes a casing 51 that defines a pump chamber 52 that accommodates the impeller 30 according to the present invention, a main shaft 57 that is arranged with the axis vertical and the lower end of which is fixed to the impeller 30. A main bearing 58 mounted above the casing and rotatably supporting the main shaft 57 with respect to the casing, and a seal device 59 for preventing leakage of fluid from between the casing 51 and the main shaft 57 are provided. The casing 51 is fixed on the tubular support base 60 by a known method. The casing 51 includes an upper disc-shaped end plate 53, a casing main body 54 defining a spiral outlet chamber 55, and a tubular cover 56. A cylindrical suction pipe 61 is connected to the lower end of the cover 56.
In the above pump, when the impeller 30 fixed to the lower end thereof is rotated by rotating the main shaft 37, the fluid is sucked into the inlet 39 of the impeller as shown by the arrow X in the suction pipe 61, and the impeller is rotated. It is pushed out radially from the outlet 38 side through the 30 flow paths 36 and flows into the outlet chamber 55. The fluid in the outlet chamber is discharged from an outlet (not shown). Note that at least a part of the inner surface of the casing may be subjected to a surface treatment using a ceramic particle-containing self-fluxing alloy spray material.
[0020]
【The invention's effect】
According to the present invention, the following effects can be obtained.
(A) Spattering of ceramic powder during thermal spraying can be minimized and the thermal spraying efficiency of ceramics can be improved.
(B) It becomes possible to efficiently disperse and take in the ceramic particles into the deposited film, thereby improving the cavitation erosion resistance and the slurry erosion resistance.
[Brief description of the drawings]
FIG. 1 is an enlarged explanatory view of a conventional thermal spray material composed of a mixed powder of a ceramic powder and a self-fluxing alloy powder.
FIG. 2 is a diagram illustrating the principle of the flame spraying method.
FIG. 3 is an enlarged explanatory view of a thermal spray material of the present invention in which a ceramic powder and a self-fluxing alloy powder are formed into a granular material.
FIG. 4 is a cross-sectional view showing experimental results of a conventional mixed-type thermal spray material and a thermal spray material of Example 1 of the present invention.
FIG. 5 is a cross-sectional view showing experimental results of a conventional mixed-type thermal spray material and a thermal spray material of Example 2 of the present invention.
FIG. 6 is a cross-sectional view showing an example of an impeller sprayed by a high-speed flame spraying method using the ceramic particle-containing self-fluxing alloy spray material of the present invention.
FIG. 7 is a sectional view of a pump including the impeller of FIG. 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Granular body 11 Ceramic powder 12 Self-fluxing alloy powder 30 Impeller 32 Hub 35 Blade 36 Flow path 50 Pump (fluid machine) 51 Casing

Claims (6)

At least one type of ceramic powder selected from the group consisting of carbides, oxides, nitrides or borides, and at least one selected from the group consisting of nickel-based self-fluxing alloy powders, cobalt-based self-fluxing alloys, and iron-based self-fluxing alloy powders One kind of self-fluxing alloy powder is mixed and agglomerated to form a granular material having an average secondary particle size larger than the average primary particle size of the powder, and the average secondary particle size of the granular material is 15 to A self-fluxing alloy spray material containing ceramic particles, which is 250 μm. The ceramic particle-containing self-fluxing alloy spray material according to claim 1, wherein R2 / R1 is 20 or less, where R1 is the average primary particle size of the ceramic powder and R2 is the average primary particle size of the self-fluxing alloy powder. A self-fluxing alloy sprayed material containing ceramic particles, characterized in that: The ceramic particle-containing self-fluxing alloy sprayed material according to claim 1, wherein the ceramic powder and the self-fluxing alloy have an average primary particle size of 1 to 60 μm and 1 to 60 μm, respectively. Particle-containing self-fluxing alloy spray material. The ceramic particle-containing self-fluxing alloy sprayed material according to any one of claims 1 to 3, wherein the ceramic powder is at least one kind of carbide powder selected from the group consisting of tungsten carbide, chromium carbide, and titanium carbide. Characteristic self-fluxing alloy spray material containing ceramic particles. An impeller comprising a hub and a plurality of blades mounted circumferentially around the hub,
An impeller, wherein at least a part of the surface of the impeller is sprayed with the ceramic particle-containing self-fluxing alloy spray material according to any one of claims 1 to 4. A hub, and an impeller having a plurality of blades attached circumferentially around the hub,
A casing that defines a chamber that rotatably houses the impeller;
With
A fluid machine in which at least a part of a surface of the impeller and / or at least a part of an inner surface of the casing are thermally sprayed with the ceramic particle-containing self-fluxing alloy spray material according to any one of claims 1 to 4.

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