JP2019094539A - Production method of metal component - Google Patents

Abstract

To provide a production method that prevents a metal component from cracking due to thermal contraction after ejection.SOLUTION: A production method of a metal component by means of a metal powder injection molding method includes: a kneading step of, after adding an organic binder to metal powder and heating, pulverizing or pelletizing to obtain an injection molding material; an insert formation step of injection molding the injection molding material and degreasing and calcining at a second temperature region to obtain the insert capable of occupying a part of a volume of the metal component; an injection molding step of ejecting the injection molding material to the insert installed in the mold to obtain a compact of a shape of the metal component; a degreasing step of degreasing the compact under a degreasing atmosphere of the first temperature region that is lower than the second temperature region; and a sintering step of sintering the degreased compact in a third temperature region having a higher temperature than the second temperature region.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a metal member.

  DESCRIPTION OF RELATED ART The manufacturing method of the metal member using the metal powder injection molding (MIM method) conventionally is known. This MIM method is a method of injection-molding a mixture of metal powder and a binder (binder), forming a part by main sintering after degreasing and presintering, and it is a complex shaped member of difficult-to-process material It is suitably used for molding.

  For example, Patent Document 1 discloses a technique for directly obtaining an end product of a turbine wheel by the MIM method. In addition, according to Patent Document 2, a sintered product having a shape similar to the final product of a turbine wheel is manufactured by MIM method, and the sintered product is cut and pressed, and then the blade position is used using a correction pin. There is disclosed a technique for correcting

Unexamined-Japanese-Patent No. 2004-149826 Unexamined-Japanese-Patent No. 2011-174096

  By the way, in manufacture of the metallic member by MIM, after forming a compact, a compact is contracted by removal of a binder in a degreasing process, and a sintering process after that, and a metallic member is finally obtained. However, since the amount of heat shrinkage in the cooling process in the mold after injection is large at thick portions, cracks occur inside when forming the green body. Further, the binder is not sufficiently removed even by heating in the above-described degreasing process, and cracking may occur in the metal member starting from the periphery of the remaining binder. In this respect, neither of the Patent Documents 1 and 2 discloses a configuration in consideration of a countermeasure against a crack by the residual binder.

  In view of the above problems, at least some embodiments of the present invention, in a method of manufacturing a metal member using a metal powder injection molding method, reduce cracks due to thermal contraction in green body molding and residual binder so as to be used after injection. It aims at preventing the crack of the metal member by shrinkage.

(1) A method of manufacturing a metal member according to at least one embodiment of the present invention,
A method of manufacturing a metal member using a metal powder injection molding method,
A kneading step of adding an organic binder to metal powder and heating to obtain an injection molding material;
An insert forming step of obtaining an insert occupying at least a part of the outer surface of the metal member by injection molding, degreasing and presintering the injection molding material;
An injection molding step of injecting the injection molding material into the inside of a mold in which the insert is installed to obtain a green body of the metal member;
A degreasing step of degreasing the green body under a degreasing atmosphere in a first temperature range to obtain a brown body;
Sintering the degreased brown body at a temperature higher than the first temperature range.

In the production of a metal member using a metal powder injection molding method, thermal contraction of the green body occurs in the mold in the cooling process after injection in the injection molding step. On the other hand, since the organic binder component is removed in the brown body after degreasing, the thermal shrinkage in the cooling process when heated is smaller than that of the green body.
In this respect, according to the manufacturing method of the above (1), the degreased and pre-sintered insert is formed in advance, and the injection molding material is injected onto the insert to form a green body. In the green body, the thickness of the organic binder-containing portion having a large shrinkage can be reduced. That is, since the thickness of the contraction portion occupied in the green body provided in the cooling process after the injection molding can be reduced, it is possible to prevent the generation of the crack in the green body in the injection molding step. In addition, since the insert is in a pre-sintered state instead of the main sintering, a gap as a ventilation circuit through which the binder heated and evaporated in the degreasing step is secured in the insert. Thereby, the air permeability of both the surface side and the insert side of the green body can be secured by sandwiching the unsintered portion, and the binder can be smoothly removed from the green body to effectively prevent the degreasing failure. Can.

(2) In some embodiments, in the method according to (1),
The sintering step is
A first sintering step of temporarily sintering the degreased brown body at a second temperature range higher than the first temperature range to obtain a temporary sintered body;
And a second sintering step of main sintering the temporary sintered body at a third temperature range higher than the second temperature range.

  According to the manufacturing method of the above (2), in the material having low sinterability, the first sintering step in which the sintering step is pre-sintered in the second temperature range, and the main sintering in the third temperature range By being configured in two steps with the second sintering step to be performed, it is possible to properly bond the insert and the other portion in the green body. In the case of a material having high sinterability, the pre-sintering step may be omitted.

(3) In some embodiments, in the method according to (2),
The insert forming step is
A pre-injection molding step of injection molding the injection molding material to obtain a preform;
A preliminary degreasing step of degreasing the preformed body under the degreasing atmosphere;
And presintering the degreased preformed body in the second temperature range.

  According to the manufacturing method of the above (3), by setting the pre-sintering temperature of the insert to a second temperature range which is the same as the pre-sintering temperature of the green body of the metal member, the insert is The occupied portion and the other portion can be made to have the same degree of sintering. Thereby, since the residual stress in the metal member after the main sintering can be reduced, the generation of the crack can be effectively prevented.

(4) In some embodiments, in the manufacturing method according to any one of the above (1) to (3),
The metal powder may be a first metal powder containing a steel material, a second metal powder containing a Ni alloy, or a third metal powder containing another alloy.

  According to the manufacturing method of said (4), the metal member and the insert which occupies at least one part of the outer surface are any one of 1st metal powder, 2nd metal powder, or 3rd metal powder other than these. Can be formed of the same material as a main component.

(5) In some embodiments, in the manufacturing method according to any one of the above (1) to (4),
The metal member is
It comprises a turbine wheel including a truncated cone-shaped hub portion and a plurality of blades circumferentially spaced on the outer peripheral surface of the hub portion,
The insert may be configured to occupy at least a portion of a back surface of the hub portion.

  According to the manufacturing method of (5), in the turbine wheel including the truncated cone-shaped hub portion, the insert is disposed so as to occupy at least a part of the back surface side of the thick wall portion of the hub portion. A turbine wheel can be formed. That is, the turbine wheel which is a metal member of complicated shape which has a thick portion can be suitably formed using a metal powder injection molding method without causing cracking or degreasing failure.

(6) In some embodiments, in the method according to (5),
The insert may include a tapered portion formed in a tapered shape from the back surface of the hub portion toward the tip surface side.

  According to the manufacturing method of the above (6), in the turbine wheel including the thick truncated cone-shaped hub portion, the insert incorporated as a part is tapered from the back surface of the hub portion toward the tip surface side By forming into the shape which has, it can narrow the distance from the surface of a hub part to the insert of the back side in the state of a green body, and can control thickness. Thus, a turbine wheel including a thick hub portion can be suitably formed using metal powder injection molding without cracking or degreasing.

(7) In some embodiments, in the manufacturing method according to (5) or (6) above,
The insert may be formed in a symmetrical shape around an axis of the turbine wheel.

  According to the manufacturing method of (7), in the turbine wheel which is a rotating body, the insert incorporated as a part can be formed in a symmetrical shape around the axis of the turbine wheel, so the weight of the turbine wheel It is possible to prevent the distribution from becoming unbalanced around the axis. That is, since it is possible to suppress the deviation of the center of gravity around the axis of the turbine wheel in the manufacturing process, it is possible to effectively suppress the occurrence of vibration or vibration at the time of rotation of the turbine wheel (metal member) after completion.

(8) In some embodiments, in the manufacturing method according to any one of the above (1) to (7),
The insert may be formed in such a shape that the outer surface thereof is less than a predetermined distance from the surface of the thick portion of the metal member.

  According to the manufacturing method of (8), the thickness of the portion of the green member of the metal member excluding the insert can be thin so as to be less than a predetermined distance (for example, 10 mm or less). Thereby, in manufacture of the metal member using the metal powder injection molding method, even if it is a metal member which has a thick part, a degreasing defect and a crack can be prevented and quality improvement can be aimed at.

  According to some embodiments of the present invention, in a method of manufacturing a metal member using a metal powder injection molding method, a metal member by shrinkage after injection and shrinkage due to thermal contraction in green body molding and binder retention is reduced. Cracking can be prevented.

It is a flowchart which shows the flow of the manufacturing method of the metal member which concerns on one Embodiment. It is the schematic which shows the manufacturing method of the metal member which concerns on one Embodiment, (A) is kneading, (B) insert formation, (C) injection molding, (D) degreasing, (E) sintering Show each process of. It is a flowchart which shows the flow of the sintering step in one Embodiment. It is a flowchart which shows the flow of the insert formation step in one Embodiment. FIG. 5 is a schematic view showing an insert forming step in one embodiment. It is the schematic which shows the metal member (turbine wheel) in one Embodiment, (A) shows a horizontal cross section, (B) shows the planar view which abbreviate | omitted a part of moving blade. FIG. 5 is a schematic view illustrating an injection molding step in one embodiment. It is the schematic which shows a 1st temperature range, a 2nd temperature range, and a 3rd temperature range. It is the schematic which shows the metal member (turbine blade) in other embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely illustrative. Absent.
For example, a representation representing a relative or absolute arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” is strictly Not only does it represent such an arrangement, but also represents a state of relative displacement with an angle or distance that allows the same function to be obtained.
For example, expressions that indicate that things such as "identical", "equal" and "homogeneous" are equal states not only represent strictly equal states, but also have tolerances or differences with which the same function can be obtained. It also represents the existing state.
For example, expressions representing shapes such as quadrilateral shapes and cylindrical shapes not only represent shapes such as rectangular shapes and cylindrical shapes in a geometrically strict sense, but also uneven portions and chamfers within the range where the same effect can be obtained. The shape including a part etc. shall also be expressed.
On the other hand, the expressions "comprising", "having", "having", "including" or "having" one component are not exclusive expressions excluding the presence of other components.

FIG. 1 is a flow chart showing the flow of the sintering step in one embodiment. FIG. 2 is a schematic view showing a method of manufacturing a metal member according to an embodiment.
As shown in FIGS. 1 and 2, the method of manufacturing a metal member according to at least one embodiment of the present invention is a method of manufacturing the metal member 1 using a metal injection molding method (MIM method). It comprises a kneading step S1, an insert forming step S2, an injection molding step S3, a degreasing step S4, and a sintering step S5.

  First, MIM method is a manufacturing technology that combines plastic injection molding and metal powder metallurgy, using metal fine powder instead of melting a metal block as a raw material, adding a resin as a connecting material without melting this Injection molding, degreasing and sintering the molded body to obtain a highly accurate metal member. According to this MIM method, it is possible to obtain a sintered body that can be treated as a final product after sintering even if it is a complex three-dimensional metal member. Each step will be described in detail below.

In the kneading step S1, for example, as shown in FIG. 1 and FIG. 2 (A), an organic binder (binder: hereinafter, also simply referred to as a binder) 16 is added to the metal powder 12 and heated for injection molding material (pellet ) Get 18). At that time, the metal powder 12 and the organic binder 16 as a binder are put into the kneader 17 and mixed uniformly.
As the metal powder 12, metal powder having an upper limit particle diameter of about 100 μm, more preferably an upper limit particle diameter of about 45 μm, having heat resistance and corrosion resistance suitable as a material of the metal member 1 as a final product by MIM method preferable. The particle diameter of the metal powder 12 is classified by a sieve, and the upper limit particle diameter becomes smaller as it is classified by a sieve with smaller mesh, and the formability such as flowability and sinterability in injection molding is improved.
The organic binder 16 may be, for example, a powdery binder made of an organic (resin) material such as polyacetal, polypropylene, polyethylene, ethylene vinyl acetate, or acrylic resin. The material of the organic binder 16 imparts fluidity (viscosity) capable of completely filling the injection molding material 18 into the inside of the mold 50 in an injection molding step S3 described later, and is hard to remain as carbide after sintering. Is selected. It is to be noted that methods for selecting materials, particle sizes, and the like of the metal powder 12 and the organic binder 16 may be those known in the prior art, and therefore will not be described in more detail in the following description.
After kneading, the resulting mixture is heated to melt the resin component, and for example, a pelletizer is used to obtain the pelletized injection molding material 18 (granulation). In another embodiment, the mixture may be heated to form an ingot, which may then be crushed to obtain granular injection molded material 18. In the present specification, although not limited, both of the above-mentioned kneading and granulation are included in the kneading step S1.

  In the insert forming step S2, for example, as shown in FIG. 1 and FIG. 2 (B), the outer surface 4 of the metal member 1 is obtained by injection molding the injection molding material 18, degreasing and presintering (FIG. 6 (A)). An insert 20 is obtained which occupies at least a part of the reference). The insert 20 in the pre-sintered state is in a state in which the metal particles are loosely bonded (necked) to each other, has a gap inside, and has air permeability. In some embodiments, the insert 20 may be integrated with the metal member 1 in the final product and be integrated into a part thereof.

In the injection molding step S3, for example, as shown in FIG. 1 and FIG. 2C, the injection molding material 18 is injected into the internal space (cavity) of the mold (die) 50 in which the insert 20 is installed A green body 30 is obtained. At that time, insert 20 is installed in one mold 50A (see FIG. 7A), the other mold 50B is matched with the mold 50A after installation, and the internal space formed by this is depressurized After evacuation, injection molding material 18 is injected into the above-mentioned internal space using injection molding machine 52 (see FIG. 7 (B)).
In the injection molding step S3, the above-mentioned injection molding material 18 is injected into the inside of the mold 50, and the green body 30 to be the metal member 1 is molded (see FIG. 7C). The injection molding material 18 is sufficiently heated and kneaded in advance by heat of about 120 to 240 ° C. in the cylinder of the injection molding machine 52 beforehand, and in a state in which smooth fluidity is given, inside the mold 50 by a predetermined pressure. It is injected. The internal shape of the mold 50, that is, the shape of the green body 30, may be about 9 to 12% larger than the metal member 1 after sintering in anticipation of the amount of shrinkage in the sintering step S5.

In the degreasing step S4, for example, as shown in FIG. 1 and FIG. 2D, the green body 30 is degreased by heating in a degreasing atmosphere of a first temperature range T1 (for example, 400 to 500 ° C .: see FIG. 8). At that time, since the insert 20 has air permeability in a pre-sintered state, the resin component in the green body 30 is melted and gasified by heating, and is evaporated from the insert 20 side in addition to the outer surface 4 side. The green body after degreasing is called a brown body. The degreasing may be performed until all the resin components are eliminated from the green body 30, and the content of the organic binder 16 may be reduced.
In the degreasing step S4, the green body 30 is placed on the sintering jig 62 and heated. The sintering jig 62 is formed in a flat plate shape having a predetermined thickness, and as its material, it does not melt or deform (soften) at the sintering temperature in the sintering step S5 described later, and In order to prevent a reaction with a TiAl alloy or the like which is a sintered material, it may be a ceramic material such as alumina, yttria and zirconia.

  In the sintering step S5, for example, as shown in FIG. 1 and FIG. 2 (E), the degreased green body 30 is sintered at a temperature higher than the first temperature range T1 to form a sintered body (silver body). The metal member 1 is obtained.

  Here, according to the above manufacturing method illustrated in a non-limiting manner in FIG. 1, the degreased and pre-sintered insert 20 is formed in advance, and the injection molding material 18 is injected onto the insert 20 to form the green body 30. In the green body 30 before the sintering step S5, the thickness of the portion which is likely to be cracked due to heat contraction can be reduced. That is, since the thickness of the contraction portion occupied in the green body 30 provided for cooling of the injection molding step can be reduced, generation of cracks in the sintered metal member 1 can be prevented. Further, since the insert 20 is in a state of not being main sintering but being temporarily sintered, a gap as a ventilation circuit through which the organic binder 16 which is heated and evaporated in the degreasing step S4 is secured in the insert 20. Thereby, the air permeability of both the outer surface 4 side and the insert 20 side of the green body 30 can be secured across the unsintered portion, and the organic binder 16 is smoothly removed from the green body 30 to cause degreasing failure. Can be effectively prevented.

  In some embodiments, for example, as shown in FIG. 3, in the above manufacturing method, the sintering step S5 may include a first sintering step S51 and a second sintering step S52.

In the first sintering step S51, the brown body 30 is temporarily sintered in a second temperature range T2 (for example, 800 to 1200 ° C .: see FIG. 8) having a temperature higher than the first temperature range T1 to obtain a temporary sintered body 40. . More specifically, in the first sintering step S51, the injection molded green body 30 is temporarily sintered together with the mold 50 at a predetermined temperature. In pre-sintering, the metal particles are in a state of being gently bonded (necked) to each other, and the size of the green body 30 is hardly reduced.
In the second sintering step S52, the temporary sintered body 40 is sintered in a third temperature range T3 (for example, 1200 to 1500 ° C .: see FIG. 8) higher than the second temperature range T2 to form the metal member 1 (silver) Get the body). The temperature of each of the above-mentioned sintering steps is properly selected depending on the type of the metal powder 12.

  According to this manufacturing method, the sintering step S5 is a first sintering step S51 in which temporary sintering is performed in the second temperature range T2, and a second sintering step S52 in which the main sintering is performed in the third temperature range T3. By configuring in two stages, it is possible to make the contraction of the green body 30 gentler than when only the main sintering is performed in the third temperature range T3. Therefore, in the green body 30, the insert 20 and the other portion can be properly connected.

  In some embodiments, the insert forming step S2 may include, for example, as shown in FIG. 4, a pre-injection molding step S21, a pre-degreasing step S22, and a pre-sintering step S23.

  In the pre-injection molding step S21, the injection molding material 18 is injection-molded to obtain a preform 24 (see FIG. 5A). That is, the preformed body 24 is a green body corresponding to the portion occupied by the insert 20 in the metal member 1. In the preliminary degreasing step S22, the preformed body 24 is degreased by heating in the degreasing atmosphere of the first temperature range T1. In the pre-sintering step S23, the degreased preformed body 24 is pre-sintered in the second temperature range T2 to obtain the insert 20 (see FIG. 5B).

  According to this manufacturing method, by setting the pre-sintering temperature of the insert 20 to the second temperature range T2 which is the same as the pre-sintering temperature of the green body 30 of the metal member 1, the insert of the green body 30 after the pre-sintering The portion occupied by 20 and the other portion can be made to have the same degree of sintering. Thereby, in sintering of the product itself, the insert 20 and the product base material around it become the same material.

  In some embodiments, the metal powder 12 may be any powder that can be used in a metal injection molding method, for example, the first metal powder 12A containing a steel material, the second metal powder 12B containing a Ni alloy, or Only one of the third metal powder 12C containing other metals may be contained. In this way, the metal member 1 and the insert 20 which occupies at least a part of the outer surface thereof can be formed of the same material.

FIG. 6 is a schematic view showing a configuration example of the metal member in one embodiment, (A) shows a side sectional view, and (B) shows a plan view.
As illustrated in FIGS. 6 (A) and 6 (B), in some embodiments, the metal member 1 may be, for example, a turbine wheel 1A of a supercharger.
The turbine wheel 1 </ b> A may be configured to include a truncated conical hub portion 2 and a plurality of blades (moving blades) 6 provided at intervals in the circumferential direction on the outer peripheral surface of the hub portion 2.
The hub portion 2 is formed so as to be axially symmetrical with respect to the rotation axis O of the turbine wheel 1A, and is formed so as to be wide on the back surface 5 side and thin on the front end side of the front. The hub portion 2 is a thick portion with a thick wall in the turbine wheel 1A.
The moving blades 6 receive energy of a working fluid (for example, exhaust of an internal combustion engine) and convert them into rotational force of the turbine wheel 1A. A plurality of moving blades 6 are provided at regular intervals in the circumferential direction of the hub portion 2. In general, these moving blades 6 are formed such that the thickness becomes thinner toward the outer peripheral side with the hub portion 2 as a base end. In FIG. 6 (B), only a part of the moving blade 6 is shown and the others are omitted.
And, the insert 20 may be configured to occupy at least a part of the back surface 5 of the hub portion 2. For example, the insert 20 may be formed in a range including the axis O of the rotation of the turbine wheel 1A in the back surface 5 of the turbine wheel 1A.

  In this way, of the turbine wheel 1A including the truncated conical hub portion 2, the insert 20 is disposed to occupy at least a part of the back surface 5 of the thick hub portion 2 to form the turbine wheel 1A. can do. That is, the metal member 1 having a complicated shape having a thick portion can be suitably formed without causing cracking or degreasing failure while using a metal powder injection molding method.

  In some embodiments, the insert 20 may be formed symmetrically around the axis O of the turbine wheel 1A. In this case, the shape is not particularly limited as long as it is axially symmetric about the axis O, and may be, for example, a cylinder, a cone, a truncated cone, a polygonal cylinder, or a polygonal pyramid.

  In this way, in the turbine wheel 1A that is a rotating body, even if there is a density difference between the insert and the turbine base material, it is possible to prevent the weight distribution of the turbine wheel from becoming unbalanced around the axis. . Therefore, since it is possible to suppress the deviation of the center of gravity around the axis O of the turbine wheel 1A in the manufacturing process, it is possible to effectively suppress the generation of vibration and vibration during rotation of the turbine wheel 1A (metal member) after completion. Can.

In some embodiments, the insert 20 may be configured to include a tapered portion 20A which is formed in a tapered shape from the back surface 5 of the hub portion 2 toward the front end side.
The tapered portion 20A may be sharpened so that its tip end has, for example, an acute angle. Further, the tip end of the tapered portion 20A may be formed flat so as to include a plane (not shown) perpendicular to the axis O, or may be formed by an arbitrary curved surface (not shown).
In some embodiments, for example, as illustrated in a non-limiting example in FIG. 6A, the insert 20 may be formed in a shape including a cylindrical portion 20B continuous to the tapered portion 20A. Good.

  In this way, the thickness can be reduced by narrowing the distance from the outer surface 4 of the hub portion 2 to the insert 20 on the back surface 5 side in the state of the green body 30. Thereby, the turbine wheel 1A including the thick hub portion 2 can be suitably formed without causing cracking or degreasing failure while using the metal powder injection molding method.

  In some embodiments, the insert 20 may be shaped such that its outer surface 22 is less than a predetermined distance from the outer surface 4 of the hub portion 2 which is a thicker portion of the metal member 1. In this case, the predetermined distance is not particularly limited as long as the degreasing of the hub portion (thick portion) 2 can be suitably performed, but may be, for example, 15 mm or less, preferably 10 mm or less.

  In this way, the thickness of the portion of the green member 30 of the metal member 1 excluding the insert 20 can be thin so as to be less than a predetermined distance (for example, 10 mm or less). Thereby, in manufacture of the metal member 1 using a metal powder injection molding method, even if it is the metal member 1 which has a thick part, a degreasing defect and a crack can be prevented and quality improvement can be aimed at.

  In some embodiments, the metal member 1 may be a member other than the above-described turbine wheel 1A, for example, a compressor wheel (not shown) of a compressor, or a turbine blade for an aircraft engine It may be

FIG. 9 shows a turbine blade 1B for an aircraft that can be applied as an example of the metal member 1 in some embodiments of a method of manufacturing a metal member to which the present invention is applied.
A plurality of turbine blades 1B are attached at predetermined intervals in the circumferential direction on an outer peripheral portion of a substantially disk-shaped turbine disk (not shown), and function as a moving blade that rotates with the turbine disk. The turbine blade 1 B includes a blade body 102 extending in the radial direction of the turbine disk, a platform 106 provided on the base end side of the blade body 102, and a tip provided on the tip end side of the blade body 102. And a shroud 108. Each tip shroud 108 is mounted on all the turbine blades 1B to form a ring-shaped shroud. A combustion gas passage A is formed by an annular (doughnut-shaped) passage surrounded by the platform 106 and the tip shroud 108.
The blade root side of the turbine blade 1B is a thick portion with a complicated shape attached to the outer periphery of the turbine disk. In some embodiments, the turbine blade 1B including the thick portion may be integrally formed using a metal powder injection molding (MIM) method. More specifically, at the time of manufacture of turbine blade 1B, insert 120 which occupies at least a part of blade root side outer surface 104 is prepared.
The insert 120 may be formed, for example, so as to have a trapezoidal cross-sectional shape in an axial view of the turbine disk.
And the turbine blade 1B can be manufactured by passing through the process similar to each step S1-S5 (or additionally, S21-S23 and / or S51-S52) mentioned above.

  In this way, it is possible to form the turbine blade 1B by arranging the insert 120 so as to occupy at least a part of the thick blade root side of the turbine blade 1B. Therefore, the metal member 1 having a complicated shape having a thick portion can be suitably formed without causing cracking or degreasing failure while using a metal powder injection molding method.

  According to the configuration described above, in the method of manufacturing the metal member 1 using the metal powder injection molding method, the binder 16 remains after degreasing and sintering, that is, the metal member due to shrinkage after injection with reduced degreasing defects. The crack of 1 can be effectively prevented.

  The present invention is not limited to the above-described embodiments, and includes the embodiments in which the above-described embodiments are modified, and the embodiments in which these embodiments are combined.

1 Metal member (Silver body)
DESCRIPTION OF SYMBOLS 1A Turbine wheel 1B Turbine blade 2 Hub part 4 Outer peripheral surface 5 Back surface 6 moving blade 12 Metal powder 12A 1st metal powder 12B 2nd metal powder 12C 3rd metal powder 16 organic binder (binder)
17 kneader 18 pellet (injection molding material)
Reference Signs List 20, 120 insert 20A taper portion 20B cylindrical portion 22, 122 outer surface 24 preformed body 30 green body (molded body)
40 temporary sintered body 50, 50A, 50B mold (mold)
52 Injection Molding Machine 60 Sintering Machine 62 Sinter Jig 102 Blade Body 104 Blade Root Side Outer Surface 106 Platform 108 Tip Shroud O Axis S1 Kneading Step S2 Insert Forming Step S3 Injection Molding Step S4 Degreasing Step S5 Sintering Step S21 Preliminary Injection molding step S22 Preliminary degreasing step S23 Pre-sintering step S51 First sintering step S52 Second sintering step T1 Degreasing temperature (first temperature range)
T2 Pre-sintering temperature (second temperature range)
T3 main sintering temperature (3rd temperature range)

Claims (8)

A method of manufacturing a metal member using a metal powder injection molding method,
A kneading step of adding an organic binder to metal powder and heating to obtain an injection molding material;
An insert forming step of obtaining an insert occupying at least a part of the outer surface of the metal member by injection molding, degreasing and presintering the injection molding material;
An injection molding step of injecting the injection molding material into the inside of a mold in which the insert is installed to obtain a green body of the metal member;
A degreasing step of degreasing the green body under a degreasing atmosphere in a first temperature range to obtain a brown body;
And Sintering the degreased brown body at a temperature higher than the first temperature range. The sintering step is
A first sintering step of temporarily sintering the degreased brown body at a second temperature range higher than the first temperature range to obtain a temporary sintered body;
The method according to claim 1, further comprising: a second sintering step of performing main sintering of the temporary sintered body in a third temperature range higher than the second temperature range. The insert forming step is
A pre-injection molding step of injection molding the injection molding material to obtain a preform;
A preliminary degreasing step of degreasing the preformed body under the degreasing atmosphere;
The method according to claim 2, further comprising a pre-sintering step of pre-sintering the degreased preform at a second temperature range higher than the first temperature range. .   The said metal powder contains only any one of the 1st metal powder containing a steel material, the 2nd metal powder containing Ni alloy, or the 3rd metal powder containing other alloys. The manufacturing method of the metal member as described in any one of 3. The metal member is
It comprises a turbine wheel including a truncated conical hub portion and a plurality of moving blades provided circumferentially spaced on the outer peripheral surface of the hub portion,
The method for manufacturing a metal member according to any one of claims 1 to 4, wherein the insert is configured to occupy at least a part of a back surface of the hub portion.   The method for manufacturing a metal member according to claim 5, wherein the insert includes a tapered portion formed in a tapered shape from the back surface of the hub portion toward the tip surface side. The method of manufacturing a metal member according to claim 5 or 6, wherein the insert is formed in a symmetrical shape around an axis of the turbine wheel. The metal insert according to any one of claims 1 to 7, wherein the insert is formed in such a shape that the outer surface thereof is less than a predetermined distance from the surface of the thick portion in the metal member. Production method.