JPH10122117A - Hydraulic machinery - Google Patents

Abstract

[PROBLEMS] To provide a hydraulic machine excellent in wear resistance and corrosion resistance, which can be used even under a condition in which a fluid contains earth and sand, and a method of manufacturing the same. A first film including at least one selected from the group consisting of chromium carbide, tungsten carbide, nickel, chromium, and cobalt on a surface in contact with a fluid of a hydraulic machine, and a group consisting of hard rubber, epoxy, polyethylene, and polyester. And a second film containing at least one member selected from the group consisting of:

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic machine having parts of a hydraulic machine having excellent wear resistance and corrosion resistance, a part thereof, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A hydraulic machine using a fluid flowing through a flow path as a working fluid includes, for example, a water turbine for power generation provided with a runner rotating with the potential energy of water as a power source, and a pump for imparting kinetic energy to the fluid by rotation of an impeller. and so on. In recent years, such a hydraulic machine has been increasingly used under conditions where a fluid contains solids, such as earth and sand. Various parts of a hydraulic machine operated under such conditions, such as pump impellers, casings, turbine runners, casings, and guide vanes, are subject to wear due to collision of solid matter (hereinafter referred to as sediment wear) and cavitation erosion. And compound damage occurs. Therefore, for example, Japanese Unexamined Patent Publication No.
No. 477 discloses that a resin lining such as rubber or a high-hardness material such as ceramics is sprayed on a damage generating portion.

[0003] The various members are manufactured by casting or can-making. In general, impellers and runners having a three-dimensional shape are often manufactured by casting. However, large-sized impellers such as power turbine impellers are partially manufactured by welding.

[0004]

As described above, when a hydraulic machine is used under conditions that include earth and sand in a fluid, various members are used to prevent damage due to earth and sand wear and cavitation erosion. A coating of a hard material is required.
However, it is not easy to coat a three-dimensionally shaped impeller, runner, casing or the like with a high hardness material.

[0005] The plating method is a method capable of easily covering even a complicated-shaped object, but has the following problem when applied to this example. That is, chromium plating (hereinafter referred to as Cr plating) is the most widely used electrolytic plating, and the film hardness belongs to the highest in the plating film, and Vickers hardness (hereinafter referred to as Hv) is about 1000. However, because of electrolytic plating, electrolytic concentration occurs due to the shape, and it is difficult to make the film thickness uniform. Further, in plating, it is difficult to form a thick film due to distortion in the film, and it is difficult to form a film having a thickness sufficient for earth and sand wear and cavitation erosion. Nickel-phosphorous plating (hereinafter referred to as Ni-P plating)
Is an electroless plating, and a film having a uniform film thickness can be formed regardless of the shape. However, the film hardness is at most about Hv 700 to 800, and does not have sufficient wear resistance against earth and sand wear and cavitation erosion. Also, as in the case of Cr plating, it is difficult to form a thick film due to distortion in the film, and it is difficult to form a film having a thickness sufficient for earth and sand wear and cavitation erosion. Furthermore, Cr plating, Ni-P
Since the plating is immersed in the bathtub, it is not practically applied to large parts such as water turbines and pumps in terms of equipment.

The hard coating formed by the thermal spraying method has sufficient abrasion resistance against earth and sand abrasion and cavitation erosion, and the thermal spraying method can easily coat a coating having a sufficient thickness. However, when the thermal spraying method is used, there is the following problem. That is, in order to form a good thermal spray coating, an appropriate distance is required for the interval between the gun and the member, and a relatively large space is required due to limitations on the size of the thermal spray gun. Therefore, it is difficult to cover a three-dimensional member having a narrow space with a good film having sufficient hardness and adhesion in all regions. For example, in the case of impellers and runners, a good coating can be formed in places where spraying is easy, such as the tip of a blade, but in a flow path such as the root of a blade, a good coating is formed due to the narrow space. Is difficult. Although the fluid velocity inside the flow path is lower than that at the blade tip, earth and sand wear still occurs, and a sufficient life cannot be obtained without measures against earth and sand wear.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a hydraulic machine having excellent wear resistance and corrosion resistance, which can be used even under a condition in which a fluid contains earth and sand. Is to do. Another object of the present invention is to provide a highly reliable hydraulic machine part having excellent wear resistance and corrosion resistance, which can be used even under conditions where the fluid contains earth and sand. Another object of the present invention is to provide a method for inexpensively manufacturing a hydraulic machine having excellent wear resistance and corrosion resistance, which can be used even under conditions where the fluid contains earth and sand.

[0008]

Means for Solving the Problems To solve the above-mentioned problems, a casing having a fluid flow passage therein, and a rotating body provided in the casing and rotating together with the fluid in the flow passage are provided. A hydraulic machine having one of the following configurations.

(A) Chromium carbide, tungsten carbide, nickel (hereinafter referred to as Ni), chromium (hereinafter referred to as Cr)
And a first film containing at least one member selected from the group consisting of cobalt (hereinafter, described as Co);
A second coating containing at least one selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester is coated. (B) In (A), the second coating is applied on the first coating.
The coating has a coated area. ◆ (C) In (A) or (B), the second film is coated on the entire surface in contact with the fluid. (D) In any one of (A) to (C), the first film contains 50 to 90% by weight of chromium carbide or tungsten carbide, preferably 7%.
A film containing 0 to 90% by weight. ◆ (E) In any one of (A) to (D), the thickness of the first coating is 0.1 mm or more and 1.0 mm or less, and at least one of hard rubber, epoxy, polyethylene and polyester is used. The film thickness of the film composed of the contained resin is 1 mm or more and 3 mm or less. ◆ (F) In any one of (A) to (F), a metal powder such as iron, copper, stainless steel, or the like is provided inside the second coating.
Alternatively, aluminum oxide, titanium oxide, magnesium oxide, chromium oxide, silicon oxide, chromium carbide, tungsten carbide,
Disperse ceramic particles such as silicon carbide and silicon nitride.

In order to solve the above problems, a hydraulic machine is manufactured by a manufacturing method having any of the following steps.

(G) Chromium carbide, tungsten carbide, nickel,
At least one selected from the group consisting of chromium and cobalt
A first coating including a seed is coated, and then a second coating including at least one selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester is coated. ◆ (H) In (G), after coating the first coating, 35
0 ° C or higher and 650 ° C or lower, desirably 400 ° C or higher, 6
Heat at a temperature of 50 ° C. or less for 1 hour to 30 hours, and then coat the second coating. ◆ (I) In (G) or (H), at least a part of the second coating is coated on the first coating. (J) In (G) or (I), a thermal spraying method, preferably a high-speed flame spraying method, is used as a method for coating the first coating.

The following effects are produced by the above configuration. ◆ Chromium carbide, tungsten carbide, Ni, C
Since the first coating containing at least one member selected from the group consisting of r and Co has a high coating hardness, at least a part of the surface of the hydraulic machine component is coated with the first coating to cause sediment wear and cavitation breakage. Abrasion resistance to corrosion can be exhibited. In particular, Cr ₃ C ₂ as chromium carbide
And a film using WC as a tungsten carbide has a film hardness of Hv1000 or more and excellent corrosion resistance. The main substances constituting earth and sand are feldspar and quartz, the highest hardness of which is Hv1000 of quartz. Since the abrasion resistance rapidly increases when the hardness of the impact particles exceeds the hardness of the colliding particles, at least a part of the impeller surface is coated with the above-mentioned coating having a coating hardness of Hv 1000 or more, so that the abrasion and cavitation damage are caused. Sufficient abrasion resistance to corrosion can be exhibited.

The first film is made of 50% Cr ₃ C ₂ or WC.
% To 90% by weight, preferably 70% to 90% by weight.
By providing a coating containing the weight%, it has excellent corrosion resistance and wear resistance against earth and sand wear. That is, the hardness of a coating composed of chromium carbide or tungsten carbide and a metal containing at least one of Ni, Cr, and Co changes depending on the amounts of Cr ₃ C ₂ and WC. C
When the amount of r ₃ C ₂ and WC is increased, the hardness of the film increases, but the toughness of the film is lost and the film becomes brittle, and the film is likely to be broken, peeled off, etc., and the reliability is lowered. When the amounts of Cr ₃ C ₂ and WC are in the range of 50% by weight to 90% by weight, sufficient film hardness against earth and sand wear and toughness can be maintained. Further, in this range, it is possible to obtain a coating hardness of Hv 1000 or more, and it has excellent corrosion resistance and abrasion resistance against earth and sand wear. However, when the sediment concentration is high, Cr ₃ C ₂ ,
It is necessary to increase the amount of WC and increase the film hardness. In this case, the amount of Cr ₃ C ₂ and WC is desirably 70 to 90% by weight.

The thickness of the first coating is 0.1 mm or more.
By setting it to 0 mm or less, a sufficient life can be guaranteed against earth and sand wear and cavitation erosion of the impeller, and good productivity and energy saving can be obtained. That is, since a large number of fine voids are present in the thermal spray coating, a coating thickness of 0.1 mm or more is required to exhibit excellent corrosion resistance and wear resistance. On the other hand, as the thickness of the sprayed film increases, the internal strain increases, and the adhesion decreases. In terms of adhesion,
This sprayed film needs to have a thickness of 1.0 mm or less. Further, considering the wear resistance of this film, if the film has a thickness of 1.0 mm, a sufficient life is expected, and it is desirable that the thickness be 1.0 mm or less from the viewpoint of reduction of work and energy saving. From the above points, when the film thickness is set to 0.1 mm or more and 1.0 mm or less, a sufficient life can be ensured against earth and sand wear and cavitation erosion of the impeller, and good in productivity and energy saving.

By using thermal spraying as a coating method, it is possible to easily coat a film having a thickness that can guarantee a sufficient life against earth and sand abrasion and cavitation erosion.
That is, when thermal spraying is used as a coating method, Ni, C
r, Co and chromium carbide have a thickness of 0.
A film thickness of 1 mm to 1 mm, and a film thickness of 0.1 mm to 0.5 mm can be formed with a film composed of Ni, Cr, Co and tungsten carbide. Therefore, if a film is formed by thermal spraying, it is possible to easily coat a film having a thickness that can guarantee a sufficient life against earth and sand wear and cavitation erosion.

After coating the first film, the temperature is raised to
By heating at a temperature of 50 ° C. or less, desirably 400 ° C. or more and 650 ° C. or less for at least 1 hour to 30 hours, a chromium carbide or a tungsten carbide;
In addition, since the adhesion between the metal phase of Ni, Cr, and Co and the chromium carbide particles or tungsten carbide particles increases within the coating composed of Ni, Cr, and Co, the hardness of the coating increases, and sediment abrasion occurs. Increases wear resistance to cavitation erosion. Further, the adhesion at the interface between the film and the base material is increased, and peeling of the film is suppressed. Therefore, even if a crack is generated in the film due to some impact, the peeling and falling off of the film is suppressed, and the reliability is increased. The higher the heating temperature, the faster the adhesion between the Ni, Cr and Co metal phases in the coating and the chromium carbide particles or tungsten carbide particles, and the faster the adhesion at the interface between the coating and the base material. A thermal strain is generated due to a difference in thermal expansion coefficient between the two.
Considering the influence of the thermal strain on the film, the temperature is preferably 650 ° C. or less. Considering the improvement rate of the film, 350 ° C.
However, below this, it takes a long time and industrial utilization becomes difficult. Considering practicality, 400 ° C. or more, 650
A temperature range of not more than ℃ is desirable. 350 ° C or higher, 650 ° C
Considering the following temperature range, heating at 350 ° C. requires 20 hours, and at 650 ° C., the effect of heating is at least 1 hour. When the temperature is examined in the temperature range of 400 ° C. or more and 650 ° C. or less, the effect converges in 30 hours. Therefore, considering the effect and energy saving, a heating time of 1 hour to 30 hours is desirable.

[0017] If thermal spraying, especially high-speed flame spraying, is used as a method for coating the first coating, a uniform and dense coating can be formed on the three-dimensionally shaped member. There are various methods for thermal spraying, and each method is applied according to its advantages and disadvantages. The spraying method capable of forming the densest film is a reduced pressure spraying method in which a plasma spraying method is performed under reduced pressure. However, according to the reduced pressure spraying method, it is necessary to put the member to be applied in a vacuum vessel for coating treatment, and it is not practical to apply to a large member as in this example. Explosive spraying and high-speed flame spraying are other methods that can coat a dense film. Explosive spraying is suitable for coating large-sized flat members because the coating area is large at one time, but it is difficult to uniformly coat three-dimensionally shaped members such as runners and impellers because the spray gun and equipment are large. It is. The high-speed flame spraying can form a dense film, the gun is relatively small, and a uniform and dense film can be formed on a three-dimensionally shaped member.

When the surface of the impeller covered with the first film is coated with a second film containing at least one selected from the group consisting of hard rubber, epoxy, polyethylene and polyester, the whole member has resistance to earth and sand wear and cavitation. Is greatly improved. As described above, high-speed flame spraying is a thermal spraying method that can form a uniform and dense coating on a three-dimensionally shaped member with a relatively small gun, but it is still good for places such as inside the flow path of the impeller of the pump. It is difficult to form a film. However, the second coating containing at least one selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester is the first coating containing at least one selected from the group consisting of chromium carbide, tungsten carbide, nickel, chromium, and cobalt. Although it is inferior to earth and sand abrasion resistance and cavitation resistance as compared with the coating, if the construction method is appropriately selected, a good coating can be applied to a portion such as the inside of the flow path of the impeller. Therefore, a coating composed of chromium carbide or tungsten carbide and Ni, Cr, Co is coated by thermal spraying, and hard rubber, epoxy, polyethylene, polyester is applied to a portion such as the inside of a flow passage where coating of the coating is difficult. If a coating composed of a resin containing at least one of the above is coated, the earth and sand wear resistance and cavitation resistance of the entire member are greatly improved.

When the second coating is coated on the surface of the impeller coated with the first coating, the base material is seamlessly coated by overlapping at least a part of the coated coating, so that sediment wear and cavitation damage are caused. Increases abrasion resistance and reliability against corrosion. Destruction and peeling of the film are likely to occur from the edge of the film. Therefore, at least one of chromium carbide or tungsten carbide and Ni, Cr, Co
The base material is covered seamlessly by partially covering the film composed of resins such as hard rubber, epoxy, polyethylene, and polyester on the film composed of metals including various types. And cavitation erosion wear resistance and reliability are increased.

[0020]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. ◆

[0021]

【Example】

Embodiment 1 FIG. 1 is a schematic sectional view of a horizontal shaft pump 1 showing a first embodiment of the present invention. The impeller 2 is fixed to a shaft 4 supported at both ends by bearings 3, is rotated by a driving machine (not shown) connected to one end of the shaft 4, and drains water sucked from both ends of the impeller from a casing 5. is there.

The parts to which the present invention is applied are the impeller 2 and the casing 5. Details will be described below taking the impeller 2 as an example. FIG. 2 shows a schematic external view of the impeller 2. Some parts are shown separately to clarify the internal structure. The impeller 2 includes a boss 21 fitted to the shaft 4, a shroud 22 surrounding the boss 21, and a blade 23 connected to the boss 21 and the shroud 22. The gap between the boss 21 and the shroud 22 forms a flow path, and the water flowing from the suction ports 24 on both sides is accelerated by the rotating impeller 2, discharged from the discharge port 25, and discharged from the pump through the flow path in the casing 5. .

When the running water flowing into the impeller 2 contains a large amount of earth and sand, earth and sand abrasion occurs due to the collision of the earth and sand particles. In order to prevent this sediment abrasion, a portion of the impeller 2 where the flowing water velocity is high and where the particle collision frequency is high, that is, a part of the blades 23 and the shroud 22 are Cr ₃ C ₂ having a thickness of 0.4 mm to 0.6 mm. -16% by weight Ni-4% by weight Cr
Sprayed film (hereinafter, Cr ₃ denoted as C ₂ -20% NiCr sprayed coating) are coated with a further whole surface film thickness 1 mm 2 mm of the epoxy resin film of the impeller 2, except the mating portion of the shaft 4 Coated. Inside the epoxy resin film,
Aluminum oxide particles are dispersed, and the amount is 50% by weight in this embodiment. Epoxy resin film is Cr ₃ C ₂ −
The portion coated with the 20% NiCr sprayed film is also coated on the upper layer, and in the overlapping portion, the lower layer is formed with Cr ₃ C ₂ −
20% NiCr sprayed film 8, 2 layers of epoxy resin film on top
It has a layer structure.

FIG. 3 shows a longitudinal section of the impeller 2 shown in FIG. In this drawing, C
Hatching is applied to the portion where the r ₃ C ₂ -20% NiCr sprayed film 8 is coated. The coating location of the Cr ₃ C ₂ -20% NiCr sprayed film 8 is near the suction port 24 and the discharge port 25, and is a location where thermal spraying is easy.

FIG. 4 is an external view of the impeller 2 of FIG. 2 as viewed from the direction b. However, in order to clarify the internal structure, the right half shroud 22 is omitted. In FIG. 4, similarly to FIG. 3, hatching is applied to the portion covered with the Cr ₃ C ₂ -20% NiCr sprayed film 8.

FIG. 5 shows a part of an enlarged vertical cross section of the impeller 2 of FIG. Cr ₃ C ₂ -20% Ni is applied to a part of the shroud 22 and the blade 24.
A Cr sprayed film 8 is coated, and an epoxy resin film 9 is further coated on the entire surface. The Cr ₃ C ₂ -20% NiCr sprayed film 8 and the epoxy resin film 9 overlap, and the lower layer is Cr ₃ C ₂
A -20% NiCr sprayed film 8 is obtained.

FIG. 6 is an enlarged longitudinal sectional view of the casing 5 at the front part of the discharge port 25. The front portion 51 of the discharge port 25 has a high flow velocity and a high frequency of particle collision, so that sediment wear is likely to occur. Therefore, a portion where the flowing water from the discharge port 25 directly collides is coated with a Cr ₃ C ₂ -20% NiCr sprayed film 8, and an entire surface of the inner surface is coated with an epoxy resin film 9. Casing 5 that can be divided into two
Is a front part 5 of the discharge port 25 which is perpendicular to the division plane.
No. 1 is capable of thermal spraying, but the other portions do not have sufficient space, and it is difficult to coat a good thermal spray coating.
Therefore, similarly to the impeller 2, the epoxy resin film 9 is coated.

Next, an embodiment of the manufacturing method of the present invention will be described with reference to FIG. The impeller 2 was manufactured by casting. The material is 13% Cr cast steel. After casting, the steel is subjected to strain relief annealing, and then finished to predetermined dimensions by cutting. Then, Cr ₃ C ₂ -20% Ni
A pretreatment is performed on the portion to be coated with the Cr sprayed film 8. First, the fats and oils are removed by washing, and then the surface is adjusted to an appropriate surface roughness by sandblasting using alumina powder.
In addition, a new surface is formed by removing the oxide film and the like. Then, Cr ₃ C ₂ −
A 20% NiCr sprayed film 8 is coated. In this embodiment, a sprayed powder obtained by pulverizing and classifying a sintered body having a composition of Cr ₃ C ₂ -20% NiCr was used. In high-speed flame spraying, a dense coating can be formed in various spraying methods, and a uniform and dense coating can be formed on a member having a relatively small spray gun and a relatively narrow space. This is the most suitable thermal spraying method for coating a three-dimensionally shaped member such as.

Next, the impeller is set in a furnace, and for 1 hour or more and 30 hours or less, 350 ° C. or more, 650 ° C. or less,
Desirably, heat treatment is performed at a temperature in the range of 400 ° C. or more and 650 ° C. or less. In this embodiment, about 1 at 550 ° C.
Hold for 5 hours, then cool in furnace. Since the impeller is a large part, it is difficult to rapidly raise and cool the temperature, and it is not appropriate from the viewpoint of thermal distortion of the coating. Therefore, the impeller was kept at 550 ° C. for 15 h in the furnace, and then cooled slowly in the furnace.

By heating at this temperature, Cr ₃ C ₂ -20
Since the adhesion between Ni, Cr and Cr ₃ C ₂ particles in the% NiCr sprayed film 8 increases, the hardness of the film increases, and the wear resistance against earth and sand wear and cavitation erosion increases. Further, the adhesive strength at the interface between the Cr ₃ C ₂ -20% NiCr sprayed film 8 and the base material is increased, and the peeling of the film is suppressed. Therefore, even if the film cracks due to any impact,
Peeling and falling off of the film are suppressed and reliability is increased. This phenomenon is not limited to the Cr ₃ C ₂ -20% NiCr sprayed film,
The same applies to a C-NiCr film and a WC-Co film.

As the heating temperature is higher, the residual strain in the weld is released, the adhesion between the Ni and Cr metal phases in the coating and the Cr ₃ C ₂ particles is increased, and the adhesion at the interface between the coating and the base material is increased. Although it advances quickly, the Cr ₃ C ₂ -20% NiCr sprayed film 8 and the base material 1
Thermal distortion occurs due to a difference in thermal expansion coefficient from 3Cr steel. Considering the influence of the thermal strain on the film, the temperature is preferably 650 ° C. or less. Further, considering the improvement rate of the thermal sprayed film, the limit is 350 ° C. If it is less than 350 ° C., it takes a long time and industrial use becomes difficult. 400 ° C or higher, 650 ° C considering practicality
The following temperature range is desirable. Considering the temperature range of 350 ° C. or more and 650 ° C. or less, heating at 350 ° C. requires 20 hours, and at 650 ° C., the effect of heating occurs in at least 1 hour. When the temperature is examined in the temperature range of 400 ° C. or more and 650 ° C. or less, the effect converges in 30 hours. Therefore, considering the effect and energy saving, a heating time of 1 hour to 30 hours is desirable. Note that this condition is Cr ₃ C ₂ -2
The WC-NiCr coating and the WC-C are not limited to the 0% NiCr sprayed coating, and the WC amount may be in the range of 50% by weight to 90% by weight.
The same applies to the o film.

After sufficient cooling, the entire surface of the impeller 2 except for the mating surface with the shaft 4 is coated with an epoxy resin film 9. In this embodiment, a solvent obtained by kneading 50% by weight of aluminum oxide particles having a particle size of 10 to 40 μm and 10% by weight of a curing agent in a bis-type epoxy was used. This solvent is applied to the entire surface of the impeller 2 except for the mating surface with the shaft 4, and is heated and cured under predetermined conditions and baked.

[Embodiment 2] FIG. 8 is a schematic external view of a water turbine 6 showing a second embodiment of the present invention. 8, 41 is a shaft, 7 is a runner, 10 is a guide vane, 11 is an upper runner cover, 12 is a lower runner cover, and 13 is a bearing. Water flows from the guide vane 10 into the runner 7 fixed to the shaft 41, and the kinetic energy of the water causes the runner 7 and the shaft 4 to move.
1 is a mechanism for generating electricity by rotating a generator (not shown) connected to one end of the shaft 41.

The parts to which the present invention is applied include a runner 7, a guide vane 10, an upper runner cover 11, and a lower runner cover 1.
2. When the running water flowing into the runner 7 contains a large amount of earth and sand, the runner 7, the guide vanes 10, and the upper and lower runner covers 11 and 12 suffer from earth and sand wear due to the collision of the earth and sand particles. In order to prevent this sediment abrasion, the runner 7, the guide vane 10, and the upper and lower runner covers 11 and 12 are provided with Cr ₃ C ₂ -20 at places where the speed of flowing water at which sand abrasion is expected to occur and where particle collision frequency is high is high. % NiCr coating, and the other part is coated with an epoxy resin coating in which 50% by weight of aluminum oxide particles are dispersed. Cr ₃ C ₂ -2
The 0% NiCr film and the epoxy resin film overlap, and the lower layer has a structure of a Cr ₃ C ₂ -20% NiCr film and the upper layer has an epoxy resin film.

Taking the runner 7 and the guide vane 10 as an example,
Details will be described below. FIG. 9 is a schematic perspective view of the runner 7. 9, 71 is a crown, 72 is a band, 7
Reference numeral 3 denotes a blade, a crown 71, a blade 73, and a band 72.
And the blades 73 are joined by welding to form the runner 7. FIG. 10 is an enlarged sectional view of a welded portion between the crown 71 and the blade 73. In FIG. 10, the hatching of the cross section of the crown 71 and the blade 73 is not distinguished to avoid complication, and the hatching of the welded portion is not performed.

Since the blade 73 has a high flow velocity in the flowing water portion and a high frequency of particle collision, the crown 73 and the band 7
2 has an inner surface coated with a Cr ₃ C ₂ -20% NiCr film 8. The epoxy resin film 9 covers the entire surface of the runner 7 and the Cr ₃ C ₂ -20% NiCr film 8 is also overcoated. The inner surface of the runner with high flow velocity is all Cr ₃ C ₂
It is desirable to cover with a -20% NiCr film 8, but a crown 71 and a blade 73, and a band 72 and a blade 73
Since the runner 7 is formed by welding, it is not possible to cover the welded portion with a thermal spray coating in advance. Therefore, after welding, the welded portion is coated with the epoxy resin film 9 to prevent damage to earth and sand wear.

Next, an example of the manufacturing method of the present invention will be described with reference to a runner 7.
This will be described with reference to FIG. FIG. 11 is a process chart showing a method for manufacturing a water turbine runner 7 according to one embodiment of the present invention. First, the crown 71, the band 72, the blade 73
Are manufactured individually. Next, the individually manufactured crown 7
1. The band 72 and the blade 73 are coated with a Cr ₃ C ₂ -20% NiCr film by a high-speed flame spraying method. Cr ₃
When covering the C ₂ -20% NiCr coating portion which becomes the welding portion is thicker than the film thickness of the Cr ₃ C ₂ -20% NiCr film, preferably stuck a metal plate having a thickness of more than twice, Cr ₃ prevent coating of C ₂ -20% NiCr film. A metal plate having a thickness of at least twice the thickness of the coating has sufficient strength and heat resistance to high-speed gas in the high-speed flame spraying method, so that scattered fracture can be prevented. If the thickness is at least twice as large as the thickness of the coating, the coating at the masking portion and the coating portion will not be continuous, and a good coating end can be formed.

Next, the crown 71, the blade 73, and the band 7
The runner 7 is formed by welding the blade 2 and the blade 73. After welding,
The weld is machined into an appropriate round shape with a grinder to prevent stress concentration during operation. Next, the runner 7 is set in a furnace, and at 350 ° C. or more for 6 hours or more and 30 hours or less.
An SR process is performed in which the temperature is maintained at 50 ° C. or lower, preferably 400 ° C. to 650 ° C. In this embodiment, 5
It was kept at 50 ° C. for about 15 hours, after which it was cooled in the furnace.
Note that 15 hours is a holding time at 550 ° C. 5
When heated at 50 ° C., the film hardness is increased by holding for about 5 hours or more, and the adhesion is significantly improved by holding for about 10 hours or more. Since the runner is a large part, it is difficult to rapidly raise and cool the temperature, and it is not appropriate from the viewpoint of thermal distortion of the coating. The runner was kept at 550 ° C. for 15 hours in a furnace and then cooled slowly in the furnace. After sufficient cooling, the oxide film of the welded portion processed into the R shape is removed again by the grinder.

Thereafter, the runner 7 excluding the fitting surface with the shaft 41 is
Is covered with an epoxy resin film. In this embodiment, a solvent obtained by kneading 50% by weight of aluminum oxide particles having a particle size of 10 to 40 μm and 10% by weight of a curing agent in a bis-type epoxy was used. This solvent is applied to the entire surface of the runner 7 except for the fitting surface with the shaft 41, and is heated and cured under predetermined conditions and baked.

Next, the guide vane 10 which is another applicable part of the present invention will be described. FIG. 12 is an external view of the guide vane 10. The guide vane 10 includes a shaft portion 101 and a blade portion 102. In this figure, Cr ₃ C ₂ -20
The portions coated with the% NiCr sprayed film and the epoxy resin film are hatched. The guide vane 10 is located in front of the runner inlet, and creates a good water flow into the runner depending on the angle of the blade 102. Therefore, the blade 102 has a high particle collision frequency, and is liable to cause earth and sand abrasion. Therefore, in this embodiment, the entire surface of the blade 102 is coated with a Cr ₃ C ₂ -20% NiCr sprayed film, and an epoxy resin film is further coated thereon.

Embodiment 3 FIG. 13 is a schematic sectional view of a vertical pump 15 showing a third embodiment of the present invention. Feather 16
Is a mechanism for rotating a shaft 17 on which a plurality of shafts are supported by a driving device (not shown) connected to one end thereof, and discharging the water sucked from the suction port 151 through the discharge port 152. In FIG. 13, 18 is a bearing, 19 is a shaft seal,
20 is a casing.

Parts to which the present invention is applied are the blade 16 and a part of the casing 20. The blade 16 will be described below as an example. FIG. 14 is a schematic external view of the blade 16. Feather 1
Reference numeral 6 denotes a structure which includes a blade portion 161 and a shaft portion 162 and is attached to an end of the shaft. In FIG.
Hatching is applied to the portions coated with the ₃ C ₂ -20% NiCr sprayed film and the epoxy resin film. The vertical axis pump of this embodiment is used for flood control drainage pumps, circulating water pumps of power plants, and the like. When used in the Yellow River, the Yangtze River, etc., particles collide violently with the blades 16 and sediment wear is likely to occur. In the present embodiment, in order to prevent earth and sand abrasion of the blade 16, Cr ₃
Covering the C ₂ -20% NiCr sprayed coating, and further coated with an epoxy resin coating thereon. The wings 16 are usually
It is a casting or cast steel and is always installed in water when used. If it made of casting and coating the Cr ₃ C ₂ -20% NiCr sprayed coating, iron content of the base and the Cr ₃ C ₂ -20% Ni
There is a possibility that electric corrosion occurs with the Cr sprayed film.

The epoxy resin film 9 not only improves the wear resistance but also prevents the above-mentioned electric corrosion and contributes to the improvement of the corrosion resistance.

Hereinafter, the effects, functions, and the results of studies common to all of the above embodiments will be described. ◆ The hardness of the Cr ₃ C ₂ —NiCr film changes depending on the amount of Cr ₃ C ₂ . When the amount of Cr ₃ C ₂ is increased, the hardness of the coating increases, but the toughness of the coating is lost and the coating becomes brittle. As a result of examining the content of Cr ₃ C ₂ with respect to the Cr ₃ C ₂ —NiCr film, it was found that the range of 50% by weight to 90% by weight was favorable for sediment wear and cavitation erosion. However, when the sediment concentration is high such as the Yellow River, the Yangtze River, or river water after heavy rain, it is necessary to increase the amount of Cr ₃ C ₂ and increase the film hardness. In this case, Cr ₃ C ₂
Is desirably 70% to 90% by weight. Ni, Cr, and Co are suitable for the metal component of the coating in terms of corrosion resistance, coating hardness, and toughness. If these metals are selected or combined, the corrosion resistance, hardness, and toughness are good.

The Cr ₃ C ₂ -20% NiCr coating has a coating hardness of about Hv1000 and has excellent corrosion resistance.
The main substances constituting earth and sand are feldspar and quartz, the highest hardness of which is Hv1000 of quartz. Sediment wear rapidly increases the wear resistance when it exceeds the hardness of the colliding particles,
By coating a coating having a coating hardness of about Hv1000, sufficient wear resistance against earth and sand wear and cavitation erosion can be exhibited.

Since a large number of fine voids are present in the thermal spray coating, the Cr ₃ C ₂ -20% NiCr coating 8 needs to have a coating thickness of 0.1 mm or more in order to exhibit excellent corrosion resistance and wear resistance. I do. On the other hand, as the thickness of the sprayed film increases, the internal strain increases, and the adhesion decreases. In terms of adhesion, C
The thickness of the r ₃ C ₂ -20% NiCr film needs to be 1.0 mm or less. Also, a Cr ₃ C ₂ -20% NiCr coating 8
Considering the abrasion resistance of the above, if the film thickness is 1.0 mm, a sufficient life is expected, and it is desirable that the thickness be 1.0 mm or less in terms of reduction of work and energy saving.

In this embodiment, Cr ₃ C ₂ -2 is used as the sprayed film.
Although a 0% NiCr coating was used, the present invention is not limited to this composition. The sediment concentration in the handling water is high,
When a higher hardness coating is required, a WC-NiCr coating or a WC-Co coating is desirable. WC-NiC
r coating, WC-Co coating as compared to the Cr ₃ C ₂ -NiCr coating excellent in high high earth and sand wear resistance, lack altitude high partial toughness, crack tends to occur. Therefore, it is an optimal film when there is no impact such as a stone collision and the concentration of earth and sand is high.

In the case of a WC-NiCr film and a WC-Co film, the film hardness changes depending on the amount of WC, similarly to the Cr ₃ C ₂ -NiCr film. Increasing the WC content increases the hardness of the film, but the film loses its toughness and becomes brittle, and the film is likely to be broken, peeled off, etc., and the reliability is reduced. When the WC content is in the range of 50% by weight to 90% by weight, the film has sufficient film hardness against earth and sand wear and can maintain toughness. Further, in this range, it is possible to obtain a coating hardness of Hv 1000 or more, and it has excellent corrosion resistance and abrasion resistance against earth and sand wear.

In the case of the WC-NiCr film and the WC-Co film, as in the case of the Cr ₃ C ₂ -NiCr film, there are many fine voids in the film. Therefore, in order to exhibit excellent corrosion resistance and abrasion resistance, the film thickness needs to be 0.1 mm or more. On the other hand, as the thickness of the sprayed film increases, the internal strain increases, and the adhesion decreases. In terms of adhesion, WC-NiC
In the case of the r film and the WC-Co film, the film thickness needs to be 0.5 mm or less. WC-NiCr coating, WC-
Considering the abrasion resistance of the Co film, if the film thickness is 0.5 mm, a sufficient life is expected, and it is desirable that the thickness be 0.5 mm or less from the viewpoint of reduction of work and energy saving.

In the above embodiment, Cr ₃ C ₂ -20% NiC
An epoxy resin film 9 having a thickness of 1 mm to 2 mm is further coated on the r film. Cr ₃ C ₂ -20% NiCr
The flow velocity is relatively low except for the portion covered with the coating film, and the frequency of impact with earth and sand is low. However, if no countermeasures against sediment abrasion are taken, abrasion occurs due to sediment abrasion and cavitation erosion, resulting in a significant decrease in performance. Furthermore, if there is no space for the thermal spraying operation, it is not possible to coat a good thermal spray coating.

The epoxy resin film never has sufficient abrasion resistance against earth and sand wear or cavitation erosion in a region where the flow velocity is high. However, if the hardness of the film is increased by dispersing ceramic particles such as aluminum oxide particles inside the resin film, sufficient wear resistance is exhibited in a portion where the flow velocity is relatively slow and the frequency of landslide is small. Also, unlike a thermal sprayed film, a good film can be easily coated even in a place such as the inside of a flow path having no space. In general, the sprayed film is peeled off from the edge of the film. By coating the sprayed film with the epoxy resin film, the end of the sprayed film becomes a lower layer of the resin film, and peeling from the end of the film is suppressed and reliability is improved. That is, the Cr ₃ C ₂ -20%
By combining the two-layer coating of the NiCr sprayed coating and the epoxy resin coating and the single-layer epoxy resin coating 9, the wear resistance of the entire component can be improved.

In this embodiment, as the resin film, a resin obtained by kneading 50% by weight of aluminum oxide particles having a particle diameter of 10 to 40 μm and 10% by weight of a curing agent in a bis-type epoxy was used. If the content of aluminum oxide particles is increased, the hardness of the resin film increases, but the toughness of the film is lost and the film becomes brittle. 20% by weight of aluminum oxide particles to 7%
When it is in the range of 0% by weight, it is possible to achieve both earth and sand wear resistance and toughness. The particle diameter is desirably equal to or greater than the size of the colliding earth and sand particles. It is said that the earth and sand particles contained in river water have a particle diameter of about 8 to 12 μm, and when used in river water, the mixed particle diameter is desirably 10 μm or more.

In this embodiment, an aluminum oxide particle and an epoxy film are used as the resin film, but the present invention is not limited to this composition. It may be a hard rubber lining or a polyethylene or polyester film. Like the epoxy film, these films can coat a good film even in a narrow space such as the inside of a flow path, and can be mixed with inorganic particles such as aluminum oxide particles. A thicker film can be formed as compared with the sprayed film, and a sufficient wear resistance can be exhibited in a place where the flow velocity is relatively slow and the frequency of landslide is small.

The particles to be mixed are not limited to aluminum oxide particles, but may be metal powders such as iron, copper, and stainless steel.
Alternatively, ceramic particles such as titanium oxide, magnesium oxide, chromium oxide, silicon oxide, chromium carbide, tungsten carbide, silicon carbide, and silicon nitride may be used. The particle diameter is desirably equal to or larger than the collision particle diameter as described above. In the case where a hard rubber lining or a polyethylene or polyester coating is used instead of an epoxy resin coating as the resin coating, the coating method is not limited to coating and baking.

[0055]

According to the present invention, it is possible to realize a hydraulic machine excellent in abrasion resistance and corrosion resistance which can be used even under the condition that the fluid contains earth and sand and the like, and can be manufactured inexpensively and efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a horizontal shaft pump showing a first embodiment of the present invention.

FIG. 2 is a schematic perspective view including a partial cross section of a pump impeller showing a first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a pump impeller showing a first embodiment of the present invention.

FIG. 4 is a schematic perspective view including a partial cross section of a pump impeller showing a first embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a pump impeller showing a first embodiment of the present invention.

FIG. 6 is an enlarged sectional view of the pump casing showing the first embodiment of the present invention.

FIG. 7 is a manufacturing procedure diagram of the pump impeller according to the first embodiment of the present invention.

FIG. 8 is a schematic perspective view including a partial cross section of a water turbine showing a second embodiment of the present invention.

FIG. 9 is a schematic perspective view of a water turbine runner showing a second embodiment of the present invention.

FIG. 10 is an enlarged sectional view of a water turbine runner according to a second embodiment of the present invention.

FIG. 11 is a manufacturing procedure diagram of a water turbine runner according to a second embodiment of the present invention.

FIG. 12 is a schematic perspective view of a water turbine guide vane showing a second embodiment of the present invention.

FIG. 13 is a schematic vertical sectional view of a vertical axis pump showing a third embodiment of the present invention.

FIG. 14 is a schematic perspective view of a vertical axis pump blade showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Horizontal axis pump, 2 ... Impeller, 3 ... Bearing, 4 ... Shaft, 5
... casing, 6 ... water wheel, 7 ... runner, 8 ... sprayed film, 9
... resin film, 10 ... guide vane, 11 ... upper runner cover, 12 ... lower runner cover, 13 ... bearing, 15 ... vertical axis pump, 16 ... blade, 17 ... shaft, 18 ... bearing, 19 ... shaft seal, 20 ... Casing, 21 boss, 22 shroud, 23 blade, 24 suction port, 25 discharge port, 41 shaft, 71 crown, 71 band, 73
Blades, 101: shaft portion, 102: blade portion, 151: suction port, 152: discharge port, 161: blade portion, 162 ...
Shaft.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Niikura 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture Inside the Hitachi Works, Hitachi, Ltd. (72) Inventor Tsugio Yoshikawa 3-Chome, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd. Hitachi Plant

Claims (9)

[Claims] A casing having a fluid passage therein;
A rotating machine disposed in the casing and rotating with the fluid in the flow path, wherein at least a part of a surface of the hydraulic machine in contact with the fluid in the flow path includes chromium carbide; Tungsten carbide, nickel,
At least one selected from the group consisting of chromium and cobalt
A first coating containing a seed and at least one selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester
A hydraulic machine characterized by being coated with a second coating containing seeds. 2. The hydraulic machine according to claim 1, further comprising a region on the first coating, the region being coated with the second coating. 3. The hydraulic machine according to claim 1, wherein the second coating is coated on the entire surface in contact with the fluid. 4. A first coating containing at least one selected from the group consisting of chromium carbide, tungsten carbide, nickel, chromium, and cobalt on at least a part of a surface of a hydraulic machine component constituting a hydraulic machine that comes into contact with a fluid. And a second coating containing at least one member selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester. 5. The component for a hydraulic machine according to claim 4, wherein the component has a region where the second coating is coated on the first coating. 6. The component for a hydraulic machine according to claim 4, wherein the second coating is coated on the entire surface in contact with the fluid. 7. A casing having a fluid passage therein.
A rotator disposed in the casing and rotating together with the fluid in the flow path, wherein at least a part of the surface of a member to be used includes chromium carbide, tungsten carbide, nickel, chromium , A first film containing at least one member selected from the group consisting of cobalt, and then at least one member selected from the group consisting of hard rubber, epoxy, polyethylene, and polyester.
A method for manufacturing a hydraulic machine, comprising coating a second coating containing a seed. 8. The method according to claim 7, wherein after coating the first film, the temperature is from 350 ° C. to 650 ° C., preferably 400 ° C.
As described above, a method for manufacturing a hydraulic machine, comprising heating at a temperature of 650 ° C. or less for 1 hour to 30 hours and then coating a second coating. 9. The method for manufacturing a hydraulic machine according to claim 7, wherein at least a part of the second coating is coated on the first coating.