JP2017180177A - Impeller manufacturing method according to thermofusion lamination forming using dissimilar material and impeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an impeller and the impeller capable of imparting erosion resistance while suppressing cost without increasing manufacturing processes.SOLUTION: In a method of manufacturing an impeller 10 according to thermofusion lamination forming, the impeller 10 in which material of a second kind of powder 202 is contained on a surface 15A of a wall 15 for dividing channels 14 of the impeller 10 and erosion resistance is imparted thereto is formed by repeating a first step S1 for supplying at least the first kind of powder 201, of the first kind of powder 201 consisting of metal material and a second kind of powder 202 capable of imparting erosion resistance, a second step S2 for applying an electron beam EB to a specified range in a target surface Tg based on cross-section data and a third step S3 for displacing a layer Ly formed through fusion and solidification by a thickness of the layer Ly with respect to a target surface Tg such that the layer Ly is laminated.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an impeller manufacturing method by hot melt additive manufacturing and an impeller formed by hot melt additive manufacturing.

An impeller (impeller) including a hub, a shroud, and a plurality of blades is used in a centrifugal rotating machine such as a centrifugal compressor, a centrifugal blower, or a centrifugal pump.
The impeller is formed with a flow path surrounded by a hub, a shroud, and adjacent blades. This flow path is designed in a complicated shape that is three-dimensionally curved in consideration of compression efficiency and the like. In general, an impeller is required to have high shape accuracy and minute surface roughness.

  Regarding the manufacturing method of the impeller, it has been conventionally performed to weld pieces produced by dividing into a plurality of parts. However, in recent years, since the cost is increased to ensure welding quality, from the lump of metal material, Often formed integrally by electric discharge machining. At the time of electric discharge machining, the flow path is carved using an electrode that matches the shape of the flow path. When electric discharge machining is performed, the altered layer formed on the surface must be removed, for example, by pickling.

By the way, water droplets and dust contained in the fluid pumped by the impeller, and particles such as foreign matter derived from the pipe collide with the impeller flow path wall, which causes wear and thinning of the impeller flow path wall due to particle erosion. The phenomenon occurs.
Therefore, erosion resistance sufficient to suppress particle erosion is imparted by coating a hard film on the walls of the flow path of the impeller (for example, Patent Document 1).

JP 2008-169799 A JP-T-2015-510979

If a hard coating is formed on the walls of the impeller flow path by chemical vapor deposition or physical vapor deposition in order to impart erosion resistance, the number of manufacturing steps increases and the cost also increases.
An object of the present invention is to provide an impeller manufacturing method and an impeller capable of imparting erosion resistance sufficient to suppress erosion due to particle collision while suppressing cost without increasing the number of manufacturing steps.

The demand for impellers varies widely depending on the specifications of the applied centrifugal rotating machine and continues to increase.
Of course, the inventors of the present invention have focused on hot melt additive manufacturing using metal powder under the circumstances where cost reduction is also desired. Hot melt additive manufacturing is a technique for forming a three-dimensional member by laminating layers obtained by melting and solidifying metal powder based on cross-sectional data without using a mold. Since no mold is used, it is easy to deal with shape changes.
At present, it has been proposed to integrally mold an impeller by additive manufacturing using an electron beam as a heat source (Patent Document 2).

Here, since additive manufacturing is performed with the selected metal powder of one composition, only the material characteristics of the metal powder are reflected in the product.
Considering mechanical properties such as cost and strength, a practically selectable metal material is, for example, a low alloy steel such as Ni—Cr—Mo steel or stainless steel.
However, it is difficult to impart erosion resistance that can suppress particle erosion by using only such a metal material.

  The present invention made therefor is a method of manufacturing an impeller by hot melt additive manufacturing, and includes at least a first type powder made of a metal material and a second type powder capable of imparting erosion resistance. A first step of supplying one kind of powder to a predetermined target surface; and a second step of irradiating a beam, which is a heat source, in a range specified in the target surface based on cross-sectional data constituting three-dimensional data; And the third step of displacing the layer formed through the melting caused by the irradiation of the beam and the solidification with respect to the target surface by the thickness of the layer, and then laminating the layers, whereby the flow path of the impeller The impeller having the erosion resistance is formed by including the second type powder material on the surface of the wall partitioning the structure.

  In this specification, “hot melt additive manufacturing” is based on cross-sectional data constituting three-dimensional data, and sequentially forms layers formed by melting and then solidifying powder supplied to a predetermined target surface. The three-dimensional member is formed by stacking.

  In the impeller manufacturing method of the present invention, a coating powder having a powder body capable of imparting erosion resistance and a metal coating applied to the powder body can be used as the second type powder.

  In the impeller manufacturing method of the present invention, in the first step, based on the cross-sectional data, the second type of powder is supplied to a range corresponding to the wall surface at or near the inlet of the impeller flow path, and the remaining portion of the impeller 1st type powder can be supplied to the range corresponding to.

  In the impeller manufacturing method of the present invention, in the second step, the electron beam or laser beam, which is a heat source, can be irradiated to a predetermined range in the target plane set in the chamber whose pressure is reduced with respect to the atmospheric pressure.

  Further, the present invention is an impeller formed by hot melt additive manufacturing, which includes a first type material that is a metal material and a second type material that can impart erosion resistance. At least a part of the surface of the wall defining the path is formed from the second type material by hot melt additive manufacturing.

  In the impeller of the present invention, the second type material may include a powder main body capable of imparting erosion resistance and a binder for bonding the powder main bodies to each other.

  In the impeller of the present invention, the second type material preferably forms the surface of the wall at or near the inlet of the flow path, and the first type material preferably forms the remainder of the impeller.

  In the impeller of the present invention, the concentration of the second type material is preferably 100% or almost 100% from the surface formed of the second type material to a predetermined thickness.

  In the impeller of the present invention, in the second region containing the second type material, the concentration of the second type material is 100% or almost 100%, and the first type material has a concentration of 100% or almost 100%. It is preferable that the density | concentration of a 2nd type material becomes low gradually as it leaves | separates from the surface between 1st area | regions included in (3).

  In the impeller of the present invention, a film covering the surface can be formed in at least a partial region of the surface of the wall formed of the first type material or the second type material.

According to the present invention, a region containing the first type powder material (first type material) and a second type powder material (second type material) by hot melt additive manufacturing. Is manufactured as an integrated unit.
Since the impeller of the present invention formed by hot melt additive manufacturing has erosion resistance due to the second type of material, a hard coating for imparting erosion resistance to the walls of the flow path is provided as a subsequent process. It is not necessary to form by vapor deposition.
That is, it is possible to suppress impeller particle erosion while reducing costs without increasing the number of manufacturing steps.

It is a top view of the impeller which concerns on 1st Embodiment. It is a perspective view of the impeller shown in FIG. (A) is sectional drawing which shows the wall of the flow path of an impeller. (B) is a schematic diagram which shows the boundary part of a dissimilar material. It is a figure which shows the additive manufacturing apparatus used for manufacture of an impeller. It is a figure which shows the procedure which manufactures an impeller by hot-melt lamination modeling. It is a figure which shows the relationship between the distance from the surface of a flow path, and the density | concentration of 2nd type material. (A)-(d) is a figure for demonstrating the example which forms the area | region from which material differs separately. (A) is sectional drawing which shows the wall of the flow path of the impeller which concerns on 2nd Embodiment. (B) is a schematic diagram which shows the coating powder used as a 2nd type powder. It is sectional drawing which shows the wall of the flow path of the impeller which concerns on the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, the basic configuration of the impeller 10 will be briefly described with reference to FIGS. 1 and 2.
The impeller 10 is provided in a centrifugal rotary machine such as a centrifugal compressor, and is assembled to a rotary shaft (not shown).
The centrifugal compressor typically includes a plurality of impellers 10 arranged coaxially, and gases such as air are sequentially compressed by the impellers 10.

As shown in FIGS. 1 and 2, the impeller 10 includes a hub 11 through which a rotation shaft (not shown) is passed through the shaft hole 110, a shroud 12 that faces the surface of the hub 11 at a predetermined interval, and a plurality of blades 13. A plurality of flow paths 14 (FIG. 1) are formed by partitioning the space between the hub 11 and the shroud 12 with a plurality of blades 13.
Each flow path 14 is partitioned between the hub 11, the shroud 12, and the adjacent blades 13 and 13. The wall 15 that partitions the flow path 14 and contacts the gas is constituted by the hub 11, the shroud 12, and the blade 13.
Each flow path 14 has an inlet 141 positioned on the inner peripheral side of the impeller 10 and an outlet 142 positioned on the outer peripheral side of the impeller 10.

As shown in FIGS. 1 and 2, the blade 13 and the flow path 14 between the blades 13 and 13 have a curved shape with respect to both the radial direction and the axial direction of the impeller 10.
When the impeller 10 is rotated in the direction of the arrow 10R by a drive unit (not shown), the gas in the flow path 14 is accelerated by the centrifugal force, so that the gas is sucked into the flow path 14 from the inlet 141. Are compressed while flowing through the flow path 14 in the direction indicated by the arrow F and discharged from the outlet 142.

Next, a characteristic configuration of the impeller 10 will be described.
The impeller 10 of the present embodiment has a main feature that it is molded by hot melt additive manufacturing using different materials in order to suppress particle erosion caused by collision of fine particles contained in gas.
The impeller 10 includes a first type material that satisfies the cost, strength, toughness and the like of the entire impeller 10 and a second type material that imparts erosion resistance sufficient to suppress particle erosion. .

  In the present specification, water droplets and dust contained in the gas flowing through the flow path 14 and fine particles such as foreign matters derived from the piping collide with the wall 15 of the flow path 14, so that the wall 15 is worn and thinned, The erosion is called “particle erosion”. Further, the resistance sufficient to suppress particle erosion is referred to as “erosion resistance”.

As the first type material, for example, low alloy steel, stainless steel, titanium alloy or the like can be used.
The low alloy steel is, for example, Ni—Cr—Mo steel, Cr—Mo steel or the like. Examples of the stainless steel include precipitation hardening type stainless steel, martensitic stainless steel, and duplex stainless steel.
As the second type material, for example, a WC composite material (cermet) mainly containing tungsten carbide (WC) can be used.
Examples of the WC composite material include WC—NiCr, WC—Co, and WC—CoCr. In addition, a Cr ₃ C ₂ composite material, alumina-titania (AlO ₃ —TiO ₂ ), chromium oxide ceramics (Cr ₂ O ₃ ), or the like can be used as the second type material.

The impeller 10 is formed by hot melt additive manufacturing using the first type material and the second type material described above.
The second type material is used for the surface of the wall 15 that defines the flow path 14, and the first type material is used for the remaining part of the impeller 10.
As shown in FIGS. 2 and 1, the surface 15A of the wall 15 of the flow path 14 faces the surface 11A of the hub 11, the inner surface 12A of the shroud 12, the ventral surface 13A of the blade 13, and the surface 15A. It is composed of a back surface 13B of the blade 13. An abdominal surface 13A of the blade 13 protrudes toward a back surface 13B of the blade 13 adjacent to the blade 13.

FIG. 3A shows a part of the surface 15 </ b> A of the wall 15 of the flow path 14. A second region 22 containing the second type material exists from the surface 15A of the wall 15 to a predetermined thickness.
The thickness 22T of the second region 22 can be determined in consideration of necessary erosion resistance performance, raw material cost, and the like. The thickness 22T of the second region 22 is preferably 1 mm to 15 mm, for example. More preferably, it is 5 mm-15 mm.

The second region 22 is densely and hardly formed from the second type material and has erosion resistance.
The second region 22 is formed integrally with the first region 21 made of the first type material.
The second region 22 is formed over the entire flow path surface 15 </ b> A extending over the hub 11, the shroud 12, and the blade 13.

FIG. 3B shows a boundary portion between the first type material and the second type material. In the boundary portion, the material concentration (volume concentration) changes.
Over the surface 15A in the second region 22 to a predetermined thickness 22T _100, it is preferable that the concentration of the second type of material is 100% or nearly 100%.
The thickness 22T ₁₀₀ is preferably ₁ μm to 3 μm, for example.

In FIG. 3B, the layer Ly (only one layer) constituting the impeller 10 is indicated by a broken line.
As will be described later, the thickness 10T of each of the plurality of layers Ly stacked is constant. The thickness 10T is preferably set to an appropriate value from the range of 10 μm to 50 μm. More preferably, it is 30 micrometers-50 micrometers.

The manufacture of the impeller 10 based on the additive manufacturing method will be described.
In the present embodiment, the impeller 10 is manufactured by hot melt additive manufacturing using an electron beam (electron beam) which is a high energy heat source.
FIG. 4 shows an example of an additive manufacturing apparatus 30 that can be used for manufacturing the impeller 10.
The additive manufacturing apparatus 30 includes an electron beam guide path 31 that guides the electron beam EB toward the target surface Tg, a chamber in which a shaped article W (impeller 10) is formed through melting and solidification caused by irradiation of the electron beam EB. 32 and a control device 33 that controls each part of the additive manufacturing apparatus 30 based on the three-dimensional data.
The inside of the electron beam guide 31 and the chamber 32 is depressurized to a predetermined degree of vacuum with respect to the external atmospheric pressure. Therefore, oxidation of the material used can be suppressed.

The electron beam guide path 31 includes an electron beam generation source 311 that emits an electron beam EB, and a focusing coil 312 and a deflection coil 313 that are all disposed around the electron beam EB.
A target surface Tg to which the electron beam EB is irradiated is set in the internal space of the chamber 32. The target surface Tg is a horizontal plane.
Inside the chamber 32, a hopper 34 for supplying the first type powder 201 made of the first type material to the target surface Tg, and a second type powder 202 made of the second type material are placed on the target surface Tg. And a movable table 36 that supports the modeled product W are provided.
In consideration of the residual stress of the shaped article W, a heating device for heating the shaped article W can be provided in the chamber 32 to control the temperature as necessary.

With reference to FIG. 4 and FIG. 5, the manufacturing method of the impeller 10 using the additive manufacturing apparatus 30 is demonstrated.
First, under the control of the control device 33, the first type powder 201 and the second type powder 202 are supplied from the hoppers 34 and 35 to the target surface Tg (powder supply step S1).
Here, based on the two-dimensional cross-sectional data (slice data) constituting the three-dimensional data, the first region 21 and the second region are formed on the layer of the impeller 10 to be formed from now on, for example, similarly to the layer Ly in FIG. When both are included, both the first type and second type powders 201 and 202 are supplied to a predetermined range within the target surface Tg. Even when the second region 22 is dispersed in a plurality of ranges separated from each other in a layer to be formed, the second type powder 202 is supplied to each range. The control device 33 determines a range in which the first type powder and the second type powder are respectively supplied to the target surface Tg and a range in which the electron beam EB is irradiated (first region 21 and second region 22). I have identified.
When only the first region 21 is included in the layer to be formed, only the first type powder 201 is supplied to a predetermined range in the target surface Tg.
The powder constituting the layer to be formed (at least the first type powder 201) is spread on the target surface Tg with a predetermined thickness. If necessary, a rake arm (not shown) that can move in parallel with the target surface Tg can be used.

Subsequently, based on the cross-sectional data, the electron beam EB is irradiated only to the range (the first region 21 and the second region 22) specified in the target surface Tg (electron beam irradiation step S2). At this time, the focus coil 312 and the deflection coil 313 are electromagnetically controlled by the control device 33, whereby the electron beam EB scans a specific range in the target surface Tg at high speed. The first and second type powders 201 and 202 are locally melted at the position where the electron beam EB is incident, and solidify after the electron beam EB has passed.
The first type and second type powders 201 and 202 before melting can be preheated.

When the irradiation of the electron beam EB to the entire range within the target surface Tg is completed, the layer Ly is formed on the target surface Tg through melting and solidification of the powder.
Then, the movable table 36 is lowered by the thickness of the layer Ly (10T in FIG. 3B) and moved so that the completed layer Ly is retracted (offset) from the target surface Tg (moving step S3). The target surface Tg is set on the surface of the layer Ly formed immediately before.

The above steps S1 to S3 are repeated until the lamination of each layer Ly is completed. Since the stacked layers Ly are bonded in close contact with each other, the impeller 10 is integrally formed.
The powders 201 and 202 supplied to the periphery of the modeled object W (impeller 10) and the positions corresponding to the inside of the flow path 14 and the shaft hole 110 are not solidified because they are not irradiated with the electron beam EB. These powders 201 and 202 can be collected and reused.

According to the above, the first region 21 formed from the first type material and the second type material are formed by the hot melt additive manufacturing using the first type powder 201 and the second type powder 202. The impeller 10 integrally including the second region 22 thus manufactured is manufactured.
Since the impeller 10 formed by the layered manufacturing process has erosion resistance due to the second region 22, a hard film for imparting erosion resistance to the wall 15 of the flow path 14 is deposited as a post process. It is not necessary to form by such processes.
That is, particle erosion of the impeller 10 can be suppressed without increasing the number of manufacturing steps and suppressing costs.

  The surface roughness Ra (JIS B 0601-2001) of the wall 15 of the flow path 14 of the impeller 10 formed by hot melt additive manufacturing is, for example, about 25 to 40 μm. The surface roughness Ra is not worse than the surface roughness (for example, about 25 μm) of the walls of the flow path of the impeller formed by casting or electric discharge machining. Therefore, the required surface roughness is obtained by performing wet polishing using a polishing liquid or dry polishing by spraying a particulate abrasive on the wall 15 of the flow path 14 of the impeller 10 formed by hot melt additive manufacturing. Can be easily reached. Such wet polishing and dry polishing can be completed in a short time.

  In addition, even if the flow path 14 of the impeller 10 is configured in a complicated shape, the second powder 202 is placed at a position corresponding to the surface 15A of the wall 15 of the flow path 14 based on the cross-sectional data of the impeller 10. According to the hot melt additive manufacturing, the erosion resistance can be imparted to the entire region of the wall 15 of the flow path 14 over the predetermined thickness from the surface 15A.

As shown in FIG. 3B, at the boundary between the first region 21 and the second region 22, the concentration of the second type material indicated by the shade of monochrome is the first type powder 201 and the second type. Due to the mixing with the powder 202, etc., the wall 15 varies depending on the distance from the surface 15A.
As an example of density variation in FIG. 6, the concentration of the two materials is 100% in the range from the surface 15A across the thickness 22T ₁₀₀ (or nearly 100%), thereafter, away from the surface 15A It becomes lower gradually. Along with this, the concentration of the first type material gradually increases, and when it moves away from the surface 15A by a certain distance or more, it reaches the first region 21 containing no or almost no second type metal material.

In the present embodiment, the concentration of the second type of metallic material in the range from the surface 15A of the thickness 22T ₁₀₀ is 100%, or nearly 100%, it is possible to obtain the mechanical properties of the second type of metallic material sufficiently Therefore, erosion resistance can be reliably imparted to the surface 15A of the wall 15 of the flow path 14.
In addition, since the second region 22 and the first region 21 are coupled with an inclination of the material concentration as in the concentration change range 22inc shown in FIG. 6, the second region 22 and the first region 21 are connected to the surface 15A. Unlike the case where they are joined without being inclined at a position separated from the surface by a certain thickness, the mechanical characteristics gradually change as the distance from the surface 15A increases. Then, since the big hardness difference between the 2nd field 22 and the 1st field 21 can be eliminated, exfoliation is prevented beforehand, and the 2nd field 22 and the 1st field 21 are made to use even for a long term. It can be kept in close contact.

In the manufacturing process (FIG. 5), both the first-type powder 201 and the second-type powder 202 are supplied to a predetermined range within the target surface Tg (step S1), and the electron Both the powders 201 and 202 are scanned by the beam EB to be melted and solidified (step S2). However, as shown in FIGS. It can also carry out separately with the 1st type powder 201 and the 2nd type powder 202. FIG.
First, as shown in FIG. 7A, only the first type metal powder 201 is supplied to the target surface Tg (first type powder supply step), and the electron beam EB is irradiated to the specific range A1. The first type metal powder 201 is melted and solidified (electron beam irradiation step). Thereby, the first region 21 is formed.
After that, as shown in FIG. 7B, the first type powder 201 is removed and the second type powder 202 is supplied to the position adjacent to the first region 21 on the target surface Tg (first type). Two kinds of powder supply steps), melting and solidifying by irradiation of the electron beam EB to the specific range A2 (electron beam irradiation step). Thereby, the second region 22 is formed in the same layer as the first region 21. The second region 22 is bonded in close contact with the first region 21.
Thereafter, as shown in FIGS. 7C and 7D, the first-type powder 201 and the second-type powder 202 are similarly produced while relatively displacing the completed layer Ly with respect to the target surface Tg. The powder supply, melting and solidification are repeated individually.

  According to the above procedure, since the first type powder 201 and the second type powder 202 are hardly mixed, the amount of the second type powder 202 is suppressed and the amount of 100 is increased over a predetermined thickness. % Or nearly 100% of the second material concentration can be achieved, thereby obtaining the desired erosion resistance.

  In the present embodiment, a laser beam can be used instead of the electron beam EB as a heat source for melting the first powder 201 and the second powder 202. In that case, the layered manufacturing apparatus 30 may be provided with a laser oscillator instead of the electron beam generation source 311.

Further, the erosion resistance is not necessarily given to the entire region of the wall 15 of the flow path 14. Since particle erosion is likely to occur remarkably at the inlet 141 of the flow path 14 and the vicinity thereof, the erosion resistance can be imparted by the second type material only at the inlet 141 of the flow path 14 and the vicinity thereof.
In that case, based on the cross-sectional data, the second type powder 202 may be supplied to the range corresponding to the surface 15A of the wall 15 in the vicinity of the inlet 141 and melted and solidified. By doing so, erosion resistance can be imparted while suppressing the cost required for the second type powder 202.

  Alternatively, erosion resistance is imparted to the other portions of the channel 14 by the third type material while the inlet 141 of the channel 14 and the vicinity thereof are imparted with the erosion resistance by the second type material. You can also It is preferable to select a material that is less expensive than the second type material as the third type material. By preparing a hopper or the like for supplying the third type powder made of the third type material, the impeller can be manufactured in the same manner as the layered modeling procedure described above.

  It is not limited to the inlet 141 and the vicinity thereof that is selected as the site using the second type material. The second type metal material is used to provide erosion resistance only at locations appropriately selected from the surfaces 13A and 13B of the blade 13 that define the flow path 14, the surface 11A of the hub 11, and the inner surface 12A of the shroud 12. Can be granted.

[Second Embodiment]
Next, an impeller according to a second embodiment of the present invention will be described.
Similar to the impeller 10 of the first embodiment, the impeller 20 of the second embodiment also includes a second region 22 that forms the surface 15A of the wall 15 as shown in FIG. 1st area | region 21 which is the remainder of the impeller 10 is provided, and it manufactures by the additive manufacturing using the 1st type powder and the 2nd type powder.

The second embodiment is different from the first embodiment in that a coating powder 40 with a metal coating 42 as shown in FIG. 8B is used as the second type powder. Others are the same as in the first embodiment.
The coating powder 40 includes a powder body 41 that can impart erosion resistance, and a metal coating 42 applied to the powder body 41. The coated powder 40 is supplied from the hopper 35 (FIG. 4) to the target surface Tg, and hot melt additive manufacturing is performed as in the first embodiment.

The powder body 41 can be formed using a hard metal material (W, Cr, etc.) or a metal compound (carbonized compound, nitride compound, oxide compound, etc.). Specifically, the powder main body 41 can be formed using a material similar to the second type material described in the first embodiment.
The powder body 41 is a spherical particle here, but may have an appropriate shape, and may further have an irregular shape.

The metal coating 42 is formed using a metal material having a melting point lower than that of the powder body 41 or a diffusion coefficient larger than that of the powder body 41.
The metal coating 42 functions as a binder that bonds the powder body 41 and the surrounding substance even when the powder body 41 does not melt or diffuse under the heating and pressure conditions of additive manufacturing.

When the metal film 42 is melted by irradiation with the electron beam EB or the laser beam, the powder bodies 41 are fused to each other through the metal film 42 and the powder body 41 is fused to the first region 21 adjacent thereto. Worn. In addition, the stacked layers Ly are also fused through the metal coating 42. The melted metal film 42 remains on the impeller 10 after molding as a binder.
On the other hand, when the metal coating 42 diffuses into the powder body 41 under the heating condition by the irradiation with the electron beam EB or the laser beam and the pressure condition in the chamber 32, the powder bodies 41 are joined to each other through the metal coating 42. At the same time, the powder body 41 is joined to the first region 21 adjacent thereto. Further, the stacked layers Ly are also bonded to each other through the metal coating 42. Also in this case, the diffused metal coating 42 remains on the impeller 10 after molding as a binder.

The metal coating 42 can be formed from an appropriate metal material having a melting point in the range of 230 ° C. to 1700 ° C., for example.
In addition, the metal coating 42 can be formed of, for example, an appropriate metal material having a self-diffusion coefficient in the solid phase in the range of 1 × 10 ⁻⁷ m ² / s to 1 × 10 ⁻²⁰ m ² / s.
Specifically, Sn, Zn, Al, Fe, Ti, etc. correspond to the metal material satisfying the above melting point and diffusion coefficient.
A metal material similar to the first type material used for the first region 21 can also be used for the metal coating 42.

The metal coating 42 is formed with a film thickness sufficient for bonding between the powder bodies 41, bonding between the first and second regions 21 and 22, and bonding between the layers Ly by fusion bonding or diffusion bonding. The thickness of the metal coating 42 is, for example, 10 nm to 100 μm. The average particle diameter of the powder body 41 is, for example, 20 μm to 100 μm.
The metal coating 42 is preferably formed on the entire outer peripheral surface of the powder body 41 with a uniform film thickness.

  The method of applying the metal coating 42 to the powder body 41 is not limited. For example, when solution reaction is used, the metal coating 42 is uniformly covered so as to cover the entire powder body 41 due to the contribution of the surface energy of the powder body 41 in the solution. A metal film 42 having a film thickness of, for example, 10 nm to 100 μm can be formed on each powder body 41 by depositing the film body with a sufficient film thickness and advancing the solution reaction while maintaining the dispersion state of the powder body 41 in the solution.

According to the second embodiment, since the powder body 41 is provided with the metal coating 42, the powder body 41 is made of a material capable of imparting high erosion resistance even if it is difficult to form by single-piece hot melt lamination molding. Can be adopted. That is, the degree of freedom in material selection is improved.
Ceramic can also be used for the powder body 41. Although it is difficult to machine an impeller having a complicated flow path 14 from a ceramic bulk, by performing layered modeling using a coating powder 40 in which a metal coating 42 is applied to a ceramic powder body 41, A ceramic dispersion type impeller 20 having a complicated flow path 14 can be manufactured. In other words, by providing the coating powder 40 which is a composite material of ceramic and metal, the impeller 20 having a wall surface of the flow channel having hardness similar to ceramic and higher toughness than ceramic can be realized.

FIG. 9 shows the wall 18 of the flow path 14 of the impeller according to a modification of the present invention.
The surface 18A of the wall 18 formed by hot melt additive manufacturing is covered with a coating 19 having a higher hardness than the surface 18A. The coating 19 has a Vickers hardness in the range of 1000 HV to 4000 HV, for example, and is formed by an appropriate method such as spin coating, physical vapor deposition, chemical vapor deposition, or the like.
The coating 19 can be formed over the entire surface 18A of the wall 18 of the flow path 14, or can be formed only in at least a partial region of the surface 18A of the wall 18.
The coating 19 covers the first material or the second material that forms the surface 18A of the wall 18.
Here, since the surface roughness of the impeller wall 18 formed by hot melt additive manufacturing is, for example, about 25 to 40 μm as described above, the minute irregularities on the surface of the base material of the impeller 10 and the coating film 19 are anchors. Strongly bonded due to the effect. Thereby, peeling of the coating film 19 can be prevented, and it can maintain in the state closely_contact | adhered to the base material.

In addition to the above, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.
In order to reduce the weight of the impeller of the present invention or to suppress deformation due to thermal stress during hot melt layered modeling, a hollow portion can be formed in a part of the impeller, particularly in a thick portion.

10 impeller 10R arrow 10T layer thickness 11 hub 11A surface 12 shroud 12A inner surface 13 blade 13A ventral surface 13B dorsal surface 14 channel 15 wall 15A surface 20 impeller 21 first region 22 second region 22T ₁₀₀ thickness 22Tinc concentration change range 30 additive manufacturing apparatus 31 electron beam guide path 32 chamber 33 controller 34, 35 hopper 36 movable table 40 coating powder 41 powder body (binding material)
42 Metal coating 110 Shaft hole 141 Inlet 142 Outlet 201 First type powder 202 Second type powder 311 Electron beam generation source 312 Focus coil 313 Deflection coil A1 Specific range EB Electron beam F Arrow Ly Layer S1 Powder supply step (First step)
S2 Electron beam irradiation step (second step)
S3 Movement step (third step)
Tg Target surface W Modeled object

Claims (10)

A method of manufacturing an impeller by hot melt additive manufacturing,
A first step of supplying at least the first type powder to the predetermined target surface among the first type powder made of a metal material and the second type powder capable of imparting erosion resistance;
A second step of irradiating a beam, which is a heat source, on a range specified in the target surface based on cross-sectional data constituting three-dimensional data;
By repeating the third step of displacing the layer formed through melting caused by irradiation of the beam and solidification with respect to the target surface by the thickness of the layer, the layer is laminated, Including the material of the second type powder on the surface of the wall defining the flow path of the impeller, and molding the impeller imparted with the erosion resistance,
An impeller manufacturing method characterized by the above. As the second type powder,
Using a coating powder having a powder body capable of imparting the erosion resistance, and a metal coating applied to the powder body,
The impeller manufacturing method according to claim 1. In the first step, based on the cross-sectional data, the second type powder is supplied to a range corresponding to the surface of the wall at or near the inlet of the flow path of the impeller, and the remaining portion of the impeller Supplying the first type powder to the corresponding range;
An impeller manufacturing method according to claim 1 or 2, wherein In the second step,
Irradiating an electron beam or laser beam as the heat source to a predetermined range in the target surface set in a chamber depressurized with respect to atmospheric pressure,
The method for manufacturing an impeller according to any one of claims 1 to 3, wherein: An impeller molded by hot melt additive manufacturing,
A first type material that is a metal material and a second type material that can impart erosion resistance;
At least a part of the surface of the wall that defines the flow path of the impeller is formed from the second type material by the hot melt additive manufacturing,
Impeller characterized by that. The second type material is:
Including a powder main body capable of imparting the erosion resistance, and a binder for bonding the powder main bodies,
The impeller according to claim 5. The second type material forms the surface of the wall at or near the inlet of the flow path,
The first type material forms the remainder of the impeller;
The impeller according to claim 5 or 6, characterized in that. The concentration of the second type material is 100% or almost 100% over a predetermined thickness from the surface formed by the second type material,
The impeller according to any one of claims 5 to 7, wherein In the second region containing the second type material, the concentration of the second type material is 100% or almost 100%, and the first type material contains the first type material at a concentration of 100% or almost 100%. Between one area,
As the distance from the surface increases, the concentration of the second type material gradually decreases.
The impeller according to claim 8. A coating covering the surface is formed in at least a part of the surface of the wall formed of the first type material or the second type material.
The impeller according to any one of claims 5 to 9, wherein

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