WO2015056513A1

WO2015056513A1 - Method for bonding metal powder injection molded bodies

Info

Publication number: WO2015056513A1
Application number: PCT/JP2014/074514
Authority: WO
Inventors: 吉澤　廣喜; 茂征佐藤; 展康津野; 夏樹米山; 修治池田; 敬史吉野内; 雅之佐竹
Original assignee: 株式会社Ihi
Priority date: 2013-10-15
Filing date: 2014-09-17
Publication date: 2015-04-23
Also published as: CA2926768C; TW201524640A; TWI511815B; CA2926768A1; CN105612015A; KR20160098182A; CN105612015B; EP3059033A1; US20160221081A1; JPWO2015056513A1; EP3059033A4; JP6245268B2

Abstract

According to this method for bonding metal powder injection molded bodies, a metal product is produced by: [1] bringing at least two metal powder injection molded bodies, each of which is obtained by kneading a metal powder and a binder and injection molding the kneaded material, into contact with each other; [2] applying a coating agent that contains nitrogen or chlorine to a bond part where the at least two metal powder injection molded bodies are in contact with each other; and [3] bonding the at least two metal powder injection molded bodies with each other at the bond part by means of degreasing or sintering. This bonding method is capable of improving the bonding strength at the bond part.

Description

Joining method of metal powder injection molding

The present invention relates to a method for joining metal powder injection moldings [method for jointing metal injection molded parts], and in particular, joining metal powder injection moldings for producing a metal product by joining a plurality of metal powder injection moldings. Regarding the method.

Metal powder injection molding method (MIM: Metal 、 Injection Molding) is a method of mixing a metal powder and a binder and then injection-molding it so that it has a predetermined shape (green part) in a vacuum or gas atmosphere. In this method, a metal product having a density exceeding 95% is manufactured by degreasing and sintering. As the binder, a mixture of a plurality of resins and waxes is used. The shape of the molded body is maintained by scattering a plurality of binder components in order.

It is preferable that a component that does not remain in the metal is used for the binder. For example, waxes such as stearic acid, paraffin wax, carnauba wax, etc., which are easily evaporated at a relatively low temperature of 250 ° C. or less, and polyethylene, polypropylene, polystyrene, EVA (ethylene vinyl acetate) that are easily decomposed and scattered at a temperature of 500 ° C. or less. It is common to use a mixture with a resin such as EEA (ethylene-ethyl acrylate copolymer resin).

Incidentally, the stationary blade of the turbine compressor is disposed between the annular inner shroud and the annular outer shroud as disclosed in Patent Document 1 below. Further, the stationary blade is formed of an alloy mainly composed of Ti or Ni, and is configured by combining a plurality of stationary blade sectors [stator [bladestsectors] divided in the circumferential direction. In general, the stator blade sector is manufactured by separately manufacturing an outer band that forms part of the outer shroud, an inner band that forms part of the inner shroud, and the wing, and brazing the outer band and inner band to the wing. Formed with.

Recently, from the viewpoint of functional improvement, the blades are made thinner and the blade surface tends to be a complicated three-dimensional curved surface, but it is difficult to maintain the shape accuracy of the blades by casting or plastic working. For this reason, it has been proposed to use the metal powder injection molding method described above for the blade manufacturing method.

The above-described stationary blade sector having a plurality of blades between the outer band and the inner band may be difficult to form by injection molding (one step of the metal powder injection molding method). For this reason, it has been proposed to form a stationary blade sector divided body having one blade between the outer band and the inner band, and to join the plurality of divided bodies to form a stationary blade sector.

The following Patent Document 2 discloses a method for joining metal powder injection-molded bodies, the purpose of which is to suppress the reduction in joining strength. In this joining method, a paste obtained by diluting a metal powder constituting the molded body and the same kind of metal powder and a water-soluble pasty substance [gelatinized soluble material] with water is used. First, the above-described paste is applied to the joint surface of the molded body before sintering, and the molded bodies are temporarily joined with the paste. Thereafter, the temporarily bonded molded bodies are sintered, and the molded bodies are bonded to each other with metal powder contained in the paste. Patent Document 2 below discloses a case where a paste is applied to a joint surface after degreasing and then sintered, and a case where the paste is applied to the joint surface and then degreased and sintered.

Japanese Unexamined Patent Publication No. 2004-197622 Japanese Laid-Open Patent Publication No. 2010-236042

In the paste described in Patent Document 2, a water-soluble pasty substance made from starch is used. Starch is a polymer composed of carbon (C), hydrogen (H) and oxygen (0), and is easily decomposed by heat. In the metal powder injection molding method, since the molded body is manufactured by scattering the binder from the green body composed of the metal powder and the binder, the size of the molded body shrinks from the size of the green body. Here, it is difficult to control the deformation of the joint surface due to shrinkage. Accordingly, when a paste (adhesive) that is easily thermally decomposed is used, the paste is decomposed and scattered at an early stage in the degreasing process or the sintering process, so that it is difficult to maintain the contact state between the contracted joint surfaces. Therefore, the effect of suppressing the decrease in bonding strength is insufficient.

An object of the present invention is to provide a method for joining metal powder injection molded bodies that can improve the joining strength.

A feature of the present invention is a method for joining metal powder injection molded bodies, in which at least two metal powder injection molded bodies that are injection molded by kneading metal powder and a binder are brought into contact with each other, and the at least two metal powder injection molding bodies are brought into contact with each other. A coating agent containing nitrogen or chlorine is applied to the joint where the metal powder injection molded body is in contact, and the at least two metal powder injection molded bodies coated with the coating agent are degreased or baked. By joining, the metal powder injection molding body which manufactures a metal product by joining the said at least 2 metal powder injection molding body in the said junction part is provided.

According to the above feature, the decomposition rate of the coating agent can be slowed by using a coating agent containing nitrogen or chlorine, and the adhesion state of the metal powder injection molded body can be more improved at the joint when degreasing or firing the metal powder injection molded body. It can be maintained for a long time, and the joint strength of the joint can be improved.

Here, the binder includes a wax that volatilizes in a predetermined temperature range and a resin that scatters in a temperature range higher than the predetermined temperature range, and at least a part of the coating agent is the at least two metal powder injections. It is preferable that when the molded body is degreased or sintered, it evaporates later than the wax and scatters faster than the resin.

Further, it is preferable that the coating agent is applied to a contact surface or a peripheral side surface of the joint portion.

Further, it is preferable that the at least two metal powder injection molded bodies are degreased or sintered in a state in which a gap at the joint portion is maintained at 0.1 mm or less.

Further, the metal product is a wing sector including a plurality of wings and a band portion that supports the plurality of wings, and each of the at least two metal powder injection molded bodies has a single wing. It is preferably a wing sector division.

Furthermore, it is preferable that a rib extending in a direction intersecting with the chord line of the wing is formed on the back surface of the surface of the band portion where the wing is erected.

Here, when the angle between the extending direction of the band portion and the extending direction of the rib in the divided body is θ, the angle θ is larger than 0 ° and not more than the stagger angle of the blade. Is preferred.

Alternatively, it is preferable that 0 ° <θ ≦ 12 °, where θ is an angle between the extending direction of the band portion and the extending direction of the rib in the divided body.

It is a flowchart of the joining method of the metal powder injection molding which concerns on embodiment. It is a perspective view of the metal product manufactured by the joining method of the said metal powder injection molding body, (a) shows the 1st example, (b) shows the 2nd example, (c) has shown the 3rd example. (A) is a perspective view which shows the metal powder injection molding after injection molding, (b) is a perspective view which shows the metal powder injection molding to which the coating agent was apply | coated. It is explanatory sectional drawing which shows the coating method of a coating agent, (a) is a 1st example, (b) is a 2nd example, (c) is a 3rd example, (d) has shown the 4th example. (A) is a front view of an outer band, (b) is a graph which shows the relationship between the extending angle (theta) of a rib, and the stability S. FIG. It is a front view of the modification of an outer band. It is explanatory drawing of the clearance test method of a junction part, (a) is a side view which shows a clearance gap adjustment state, (b) is a side view which shows a joining completion state.

Hereinafter, an embodiment of a method for joining metal powder injection molded bodies will be described with reference to the drawings.

In the joining method of the metal powder injection molded body of the present embodiment, the metal powder injection molded body 2 obtained by kneading the metal powder and the binder and injection molding are joined together to degrease (debinder) or sinter. By performing [sintering] (calcining), the metal product 1 is manufactured. Here, after the coating agent 4 containing nitrogen (N) or chlorine (Cl) is applied to the joint portion 3 of the metal powder injection molded body 2, the metal powder injection molded bodies 2 are bonded to each other and degreased or sintered. The

Specifically, as shown in FIG. 1, a kneading step S1 for kneading metal powder and a binder, an injection molding step S2 for heating and melting the kneaded raw material and injecting it into a mold, and taking out from the mold The metal powder injection-molded bodies 2 are combined and the coating step S3 for applying the coating agent 4 to the joint 3 with a soldering iron or the like, and the metal powder injection-molded body 2 coated with the coating agent 4 is degreased in a heating furnace. The metal product 1 is manufactured through a degreasing step S4 and a sintering step S5 in which the degreased metal powder injection molded body 2 is sintered in a heating furnace.

The metal product 1 is a part of a stationary blade unit of a turbine compressor, for example. The stationary blade unit includes an annular inner shroud, an annular outer shroud, and a plurality of stationary blades disposed therebetween. The stationary blade unit is manufactured by combining a plurality of stationary blade sectors divided in the circumferential direction. The metal product 1 is a stationary blade sector.

A metal product 1 (stator blade sector) shown in FIG. 2A includes an outer band 11 that is a part of an outer shroud, an inner band 12 that is a part of an inner shroud, and an outer band 11 and an inner band 12. It is comprised by the some stationary blade 13 arrange | positioned between. In addition, the dashed-dotted line in FIG.

The outer band 11 has a shroud portion 11a that forms a flow path surface on the outer peripheral side of the stationary blade 13, and hook portions 11b that are formed at both ends of the shroud portion 11a. A step 11d is formed between the hook portion 11b and the shroud portion 11a, and the step 11d is locked to a rail formed in the turbine housing. A concave portion is formed by a shroud portion 11a and a hook portion 11b on the back surface (surface opposite to the flow path surface) of the surface on which the stationary blade 13 of the outer band 11 is erected. In the recess, a rib 11c that connects the pair of hook portions 11b is formed on the shroud portion 11a.

The inner band 12 includes a shroud portion 12a that forms the inner peripheral flow path surface of the stationary blade 13, and a slot portion 12b that is formed at each end edge in the axial direction of the shroud portion 12a. The slot portion 12b is formed by folding the side edge of the shroud portion 12a. By inserting plate parts between the pair of slot portions 12b, the inner peripheral ends of the plurality of stationary blade sectors are connected, and the inner band 12 formed by the plurality of shroud portions 12a is held in an annular shape. The rib 11c mentioned above reinforces the outer band 11 and suppresses deformation of the outer band 11 in the degreasing step S4 and the sintering step S5. The effect regarding the rib 11c will be described later.

The metal product 1 is not limited to the configuration described above. As shown in FIG. 2B, the metal product 1 may be a stationary blade sector without the rib 11c. As shown in FIG. 2C, the metal product 1 may be a moving blade sector that is a part of a moving blade unit of a turbine compressor. The metal product 1 as a moving blade sector is constituted by an outer band 11 constituting a part of the outer shroud and a plurality of moving blades 14 coupled to the outer band 11. In addition, the dashed-dotted line in FIG.2 (b) and FIG.2 (c) has shown the junction part 3. FIG.

Further, the metal product 1 is not limited to the stationary blade sector or the moving blade sector, and includes all parts manufactured by joining a plurality of metal powder injection molded bodies 2. Moreover, the structure of the outer band 11 and the inner band 12 mentioned above is an example, and is not limited to the shape mentioned above.

The metal product 1 described above has a complicated shape, and it may be difficult to manufacture by one injection molding while maintaining shape accuracy. Further, when the metal product 1 is enlarged, the weight increases and deformation may occur during degreasing or sintering. Therefore, in the present embodiment, as shown in FIG. 3A, by joining a plurality of metal powder injection molded bodies 2 (divided bodies of the blade sector), a metal as shown in FIG. Product 1 is produced. Each metal powder injection molded body 2 is
Since it has a relatively simple shape having a single vane 13 between the outer band 11 and the inner band 12, it is manufactured by one injection molding while maintaining the shape accuracy. Can do.

A metal product 1 manufactured by joining a plurality of metal powder injection-molded bodies 2 includes a plurality of blades (static blades 13) and band portions (outer band 11 and inner band 12) that support the blades. A sector (for example, a stationary blade sector). The metal powder injection molded body 2 is a component obtained by dividing the blade sector into blades. Therefore, even if the metal product 1 has a complicated shape, the metal powder injection-molded body 2 has a shape that can be easily injection-molded, and the shape accuracy can be maintained. In the following description, the same reference numerals as those of the metal product 1 are used for the metal powder injection-molded body 2 (outer band 11, inner band 12, stationary blade 13 and the like).

Each step of the flowchart of FIG. 1 will be described. In the kneading step S1, the metal powder as the raw material of the metal powder injection molded body 2 and the binder are kneaded and pelletized. As the metal powder, for example, stainless steel (SUS), titanium, various alloys, various ceramics, etc., having a particle diameter of about 10 to 20 μm are used.

The binder contains a wax that volatilizes in a predetermined temperature range and a resin that scatters in a higher temperature range than the wax. The wax is, for example, stearic acid, paraffin wax, carnauba wax, etc., which are easily evaporated at a relatively low temperature of 250 ° C. or lower. The resin is, for example, polyethylene, polypropylene, polystyrene, EVA (ethylene vinyl acetate), EEA (ethylene-ethyl acrylate copolymer resin) and the like which are easily decomposed and scattered at a temperature of 500 ° C. or less. obtain). In addition to the wax and the resin, a lubricant, a surfactant, or the like is added to the binder as necessary.

In the injection molding step S2, the metal powder injection molded body 2 shown in FIG. 3 (a) is formed. The metal powder injection molded body 2 is also called a green body. Since the metal powder injection molded body 2 contains a binder in addition to the metal powder constituting the metal product 1, the size of the metal powder injection molded body 2 is larger than that of the metal product 1.

In the coating step S3, as shown in FIG. 3B, the plurality of metal powder injection molded bodies 2 are assembled so as to have the shape of the metal product 1, and the coating agent 4 is applied to the joint portion 3. The coating agent 4 is, for example, a wax or resin containing nitrogen (N) or chlorine (Cl). At least a part of the coating agent 4 includes a material that scatters later than the wax contained in the binder during degreasing or sintering, and a material that scatters earlier than the resin contained in the binder during degreasing or sintering. Here, “at least a part of the coating agent 4” means that a part of the component contained in the coating agent 4 scatters earlier than the wax contained in the binder, or scatters later than the resin contained in the binder. It means to do.

Specifically, as the coating agent 4, a wax having a urethane group (—NHCOO—) or an amide group (—CONH ₂ ), a chlorinated wax, or the like, or a hot melt adhesive having a urethane group can be used. Products include Hi-Bon (registered trademark: Hitachi Kasei Polymer Co., Ltd.), Macromelt (registered trademark: Henkel AG & Co. KGaA) EMPARA (registered trademark: Ajinomoto Fine-Techno Co., Inc.) and the like.

If the coating agent 4 is scattered at an early stage of the degreasing step S4 and the sintering step S5, which will be described later, a gap is generated in the joint 3 of the metal powder injection molded body 2, and the strength of the metal product 1 after sintering. Will fall. However, since the coating agent 4 of the present embodiment is a material that is not easily decomposed by heat, that is, a wax or resin containing nitrogen (N) and / or chlorine (Cl), the degreasing step S4 and the sintering step S5 are fast. There will be no splashes in stages. The coating agent 4 may be a mixture of a wax containing nitrogen (N) and / or chlorine (Cl) and a resin containing nitrogen (N) and / or chlorine (Cl).

By using the coating agent 4 described above, at least a part of the coating agent 4 is scattered later than the wax contained in the binder at the time of degreasing or sintering, or faster than the resin contained in the binder at the time of degreasing or sintering. Can be scattered. Since the coating agent 4 includes a material that scatters later than the wax of the binder to be degreased, scattering of the coating agent 4 in the degreasing step S4 can be suppressed, and the adhesion (temporary bonding) function of the coating agent 4 can be maintained for a long time.

In addition, since the coating agent 4 includes a material that scatters faster than the resin contained in the binder during degreasing or sintering (that is, at least a part of the coating agent 4 remains until before and after the scattering of the binder resin), sintering is performed. In step S5, the metal powder can be sintered in a well-balanced manner without the binder resin blocking the scattering path. As a result, deformation of the metal product 1 can be suppressed. (Note that “deformation” here does not include shrinkage from the metal powder injection molded body 2 to the metal product 1 due to sintering.) Also, the metal powder injection molded body 2 (Brown body) after the degreasing step S4. In other words, the strength of the metal product 1 after sintering can be improved.

The above-described coating agent 4 is applied to the joint 3 by being heated and melted by a soldering iron, a brush, a roller, a spraying, an immersion, or the like. The For example, when a soldering iron is used, the coating agent 4 having a softening point of a soldering iron operating temperature of 330 ° C. or lower is used. The coating agent 4 is applied to the contact surface [contact surface] 3 a or the circumferential surface 3 b of the joint 3.

In the first example shown in FIG. 4A, the coating agent 4 is applied to the contact surface 3a. When the coating agent 4 is applied to the contact surface 3a, the adhesive force (bonding force) of the bonding portion 3 can be improved. However, it is preferable that the gap g of the joint portion 3 is maintained at 0.1 mm or less. If the gap g is widened, the strength of the joint 3 of the metal product 1 is reduced and the metal product 1 is deformed.

In the second example shown in FIG. 4B, the coating agent 4 is applied to the contact surface 3a and the peripheral side surface 3b. The contact surface 3 a is a facing surface in the joint portion 3 of the metal powder injection molded body 2, while the peripheral side surface 3 b is a side surface in the joint portion 3 of the metal powder injection molded body 2. By applying the coating agent 4 to the peripheral surface 3b in addition to the contact surface 3a, the amount of application to the contact surface 3a can be reduced, and the gap g can be easily adjusted to 0.1 mm or less. Moreover, since an adhesion (joining) area can be increased, the adhesive force (joining) of the joining part 3 can be improved.

In the third example shown in FIG. 4C, the coating agent 4 is applied to the peripheral side surface 3b. Here, the coating agent 4 is applied to the entire periphery of the peripheral side surface 3 b in the joint portion 3. By applying the coating agent 4 only to the peripheral side surface 3b, the gap g can be easily adjusted to 0.1 mm or less. In addition, the coating agent 4 applied to the peripheral side surface 3b is heated and melted in the degreasing step S4 or the sintering step S5 and naturally permeates the contact surface 3a. Therefore, the adhesive force (joining force) of the joint part 3 can be improved also by the contact surface 3a while maintaining the gap g below a desired value.

In the fourth example shown in FIG. 4D, the coating agent 4 is applied to a part of the peripheral side surface 3b. When the joining part 3 has a complicated shape, the coating agent 4 may be applied only to a place where it can be easily applied. When the contact surface 3a extends in the vertical direction as shown in FIG. 4D, the coating agent 4 applied to the upper peripheral side surface 3b penetrates the contact surface 3a by gravity.

As shown in FIG. 3B, the metal powder injection molded body 2 coated with the coating agent 4 is placed on the support block 5 and sent to the degreasing step S4. Here, by making the height h of the step 11 d of the outer band 11 coincide with the height h of the edge of the inner band 12, the stationary blade 13 is placed horizontally with the step 11 d applied to the corner of the support block 5. Can be placed.

Further, when the height h described above does not match, when the stationary blade 13 is leveled with the step 11 d of the outer band 11 applied to the corner of the support block 5, the edge of the inner band 12 and the support block 5 are There may be a gap between them. In such a case, an auxiliary support block (not shown) that fills the gap between the edge of the inner band 12 and the support block 5 may be inserted. Alternatively, if the stationary blade 13 is leveled with the end of the inner band 12 in contact with the support block 5, a gap may be generated between the step 11 d of the outer band 11 and the corner of the support block 5. In such a case, an auxiliary support block (not shown) that fills the gap between the step 11d and the support block 5 (corner thereof) may be inserted.

Since the binder is removed in the degreasing step S4 and the sintering step S5, the size of the metal product 1 after the sintering is contracted as a whole than the size of the metal powder injection molded body 2. For this reason, the stationary blade 13 can be contracted substantially horizontally by placing the stationary blade 13 horizontally. As a result, the bonded metal powder injection-molded body 2 can be contracted as a whole in a balanced manner, and deformation due to distortion during contraction can be suppressed.

In the degreasing step S4, the wax contained in the binder is removed. The heating temperature in the degreasing step S4 is generally lower than the heating temperature in the sintering step S5. For this reason, you may heat the metal powder injection molding 2 with the degreasing apparatus different from the sintering furnace used by sintering process S5. Of course, the metal powder injection molded body 2 may be degreased by controlling the temperature of the sintering furnace used also in the sintering step S5.

In the sintering step S5, the resin contained in the binder is removed, and the metal powder is sintered. For example, when IN718 [IN: Inconel (registered trademark: Special Metals Corporation)], which is a Ni-based alloy, is used as a metal powder, sintering is performed in a non-oxidizing atmosphere exceeding 1200 ° C. It is preferable to do. For the metal product 1 after sintering, as post-processing, the density may be measured for confirmation of the progress of sintering, press processing may be performed for fine adjustment of the dimensions, or end face processing. For this purpose, electric discharge machining may be performed, or a grinding or polishing treatment may be performed to adjust the surface assembly.

The above-described rib 11c (see FIGS. 2A, 3A, and 3B) will be described. As shown in FIG. 5A, ribs 11c are extended on the back surface of the outer band 11 (band part). The extending direction Lr of the rib 11 c intersects the chord line Lc of the stationary blade 13. The angle of the rib 11c with respect to the extending direction Le (vertical direction in the case of FIG. 5A) of the outer band 11 is θ (> 0: the magnitude of the angle), and the width of the outer band 11 of the metal powder injection molded body 2 is When A and its height are B, the dimensional stability S (dB: decibel) of the metal powder injection molded body 2 (metal product 1) can be obtained by S = 10 · log ₁₀ (B / A). .

The metal powder injection molded body 2 in which the angle θ of the rib 11c is 0 °, 6 °, and 12 ° is molded, and the shape of the outer band 11 after the sintering is measured three-dimensionally. It compared with the shape of the metal powder injection molding 2 (metal product 1). The comparison result is shown in FIG. When the stability S is high, the dimensional difference from the uniformly contracted metal powder injection molded body 2 is small. On the contrary, when the stability S is low, the dimensional difference from the uniformly contracted metal powder injection molded body 2 is large.

As shown in FIG. 5B, the stability S is higher at θ = 6 ° or 12 ° than at θ = 0 °. Therefore, the rib 11c preferably increases the angle θ (that is, increases the crossing angle with the chord line Lc). However, even when θ = 0 °, the stability S is high enough to maintain the shape accuracy of the metal product 1 depending on conditions such as the size, shape, and weight of the metal powder injection molded body 2. There may be cases. Therefore, the case where the angle θ = 0 ° is not excluded.

Also, if the angle θ of the rib 11c is too large, deformation during sintering due to the weight of the rib 11c may be promoted. Therefore, it is preferable to set an upper limit for the angle θ. Considering the above, it is preferable that the upper limit of the angle θ is a stagger angle λ (> 0: the magnitude of the angle) of the stationary blade 13. As shown in FIG. 5A, the “stagger angle λ” is an angle of the chord line Lc with respect to the turbine axial direction La (in the case of FIG. 5A, parallel to the extending direction Le). Specifically, the upper limit of the angle θ is preferably set to a value in the range of 6 ° to 12 ° based on the test results described above. However, the upper limit of the angle θ is not limited to this value (range) and can be set for each metal powder injection-molded body 2 according to the weight of the rib 11c.

That is, it is preferable that the angle θ between the extending direction Le of the outer band 11 and the extending direction Lr of the rib 11c is greater than 0 ° and equal to or less than the stagger angle λ. In particular, considering only deformation due to shrinkage, the angle θ is particularly preferably the same as the stagger angle λ. Here, since the stagger angle λ of the stationary blade 13 is determined to some extent, specifically, it is preferable that 0 ° <θ ≦ 12 °. The direction of the angle θ from the extending direction Le of the outer band 11 to the extending direction Lr of the rib 11c is opposite to the direction of the stagger angle λ from the turbine axial direction La to the chord line Lc.

FIG. 6 shows a modification in which the end surface of the metal powder injection molded body 2 is inclined with respect to the turbine axial direction La. As shown in FIG. 6, depending on the relationship with the stagger angle λ of the stationary blade 13, the rib 11c may be inclined in this way. In this modification, the extending direction Le of the outer band 11 and the turbine axial direction La are not parallel. In the case as shown in FIG. 6, the difference between the overhangs OH1 and OH2 of the outer band 11 with respect to the rib 11c can be reduced, and the deformation due to distortion at the time of contraction of the metal powder injection molded body 2 (metal product 1) is effectively suppressed. You can also

Next, the gap g (see FIG. 4A) of the joint 3 described above will be described. As shown in FIG. 7A, two metal powder injection molding plates 6 are prepared, and the other metal powder injection molding plate 6 is mounted on one metal powder injection molding plate 6 using a spacer 7. A gap was formed between the two metal powder injection molding plates 6 by inclining. The size of the gap can be adjusted by changing the horizontal position of the spacer 7. The coating agent 4 was apply | coated to this clearance gap, the metal powder injection molding board 6 was degreased and sintered, and the clearance gap C which can join the two metal powder injection molding boards 6 with sufficient intensity | strength was measured. The gap C that can realize sufficient bonding strength was 0.1 mm. Therefore, it is preferable that the gap g of the joint portion 3 is 0.1 mm or less.

It should be noted that the gap C can be changed according to the metal powder, the binder, and the like that are the raw materials of the metal powder injection molding plate 6. That is, the gap g of the joint portion 3 is not necessarily limited to 0.1 mm or less, and is empirically preferably 0.1 mm to 0.5 mm.

According to the bonding method of this embodiment, since the coating agent 4 contains nitrogen (N) or chlorine (Cl), the decomposition rate of the coating agent 4 can be slowed. Therefore, the adhesion state between the metal powder injection molded bodies 2 at the time of degreasing or sintering can be maintained for a longer time, and the bonding strength of the bonding portion 3 can be improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, ribs may be formed on the inner band 12. Since the rib 11c is provided for improving the shape accuracy of the metal product 1 (metal powder injection molded body 2) during degreasing or sintering, it may be cut by the time when the stationary blade unit is completed (ribs). Even if 11c is cut, the angle θ of the rib 11c can be determined from the cutting trace). A plurality of ribs 11c may be provided in one metal powder injection molded body 2.

Claims

A method for joining metal powder injection moldings,
At least two metal powder injection-molded bodies that are injection-molded by kneading metal powder and a binder are brought into contact with each other,
Applying a coating agent containing nitrogen or chlorine to the joint where the at least two metal powder injection molded bodies are in contact,
By degreasing or sintering the at least two metal powder injection molded bodies in which the coating agent is applied to the joint, the metal products are manufactured by joining the at least two metal powder injection molded bodies at the joint. A method for joining metal powder injection molded bodies.
A method for joining metal powder injection molded bodies according to claim 1,
The binder includes a wax that volatilizes in a predetermined temperature range, and a resin that scatters in a temperature range higher than the predetermined temperature range,
At least a part of the coating agent volatilizes slower than the wax and scatters faster than the resin during degreasing or sintering of the at least two metal powder injection molded bodies, and the joining method of the metal powder injection molded bodies .
A method for joining metal powder injection molded bodies according to claim 1 or 2,
The joining method of the metal powder injection molding body by which the said coating agent is apply | coated to the contact surface or peripheral side surface of the said junction part.
A method for joining metal powder injection molded bodies according to any one of claims 1 to 3,
A method for joining metal powder injection molded bodies, wherein the at least two metal powder injection molded bodies are degreased or sintered in a state where a gap in the joint portion is maintained at 0.1 mm or less.
A method for joining metal powder injection molded bodies according to any one of claims 1 to 4,
The metal product is a wing sector including a plurality of wings and a band portion supporting the plurality of wings;
The method for joining metal powder injection molded bodies, wherein each of the at least two metal powder injection molded bodies is a divided body of the blade sector having a single blade.
It is a joining method of the metal powder injection molding object according to claim 5,
A method for joining metal powder injection moldings, wherein a rib extending in a direction intersecting a chord line of the wing is formed on the back surface of the surface of the band portion on which the wing is erected.
It is a joining method of the metal powder injection molding object according to claim 6,
When the angle between the extending direction of the band portion and the extending direction of the rib in the divided body is θ, the angle θ is greater than 0 ° and equal to or less than the stagger angle of the blade. Body joining method.
It is a joining method of the metal powder injection molding object according to claim 6,
A joining method of metal powder injection molded bodies, wherein 0 ° <θ ≦ 12 °, where θ is an angle between the extending direction of the band portion and the extending direction of the rib in the divided body.