JPH08340666A - Metal powder composite sintered component, metal powder extruder of metal powder composite material and method of extrusion molding of metal powder composite material - Google Patents

Abstract

PURPOSE: To obtain a metal powder composite sintered unit which is suitable for a rotor by a method wherein a composite die is so constructed as to have through-holes which are kneaded material flow paths and have slit-type spaces with which a second extruder is linked in order to extrude a composite kneaded unit. CONSTITUTION: A plurality of through-holes 2 of which kneaded material flow paths are composed are formed by thin tube-type outer walls 7 in a composite die 1. The kneaded material supplied from the rear is molded so as to have the shapes of the cross-sections of the through-holes 2 and extruded forward. On the other hand, if the other kneaded material is supplied to the outer circumferential part of the composite die 1, the slit-type spaces 3 defined by the outer walls 7 of the through-holes 2 and mandrels 4 are filled with the kneaded material which is molded so as to have the shapes of the cross-sections of the slit-type spaces 3 and extruded forward. If both kneaded material extruded units are made to pass through the composite die 1, as the thin outer walls 7 by which the through-holes 2 and the slit-type spaces 3 are separated from each other do not exist outside the composite die 1, a composite unit is formed. With this constitution, a rotor having a complex shape can be obtained easily as a metal powder composite sintered unit by integral extrusion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal powder composite sintered component in which powders of different metals or alloys are composite-sintered as one or a plurality of composite layers, and an extrusion molding apparatus and an extrusion apparatus suitable for manufacturing the same. Involved in the molding method.

[0002]

2. Description of the Related Art Generally, as a method for obtaining a composite material by powder metallurgy, an extrusion molding method, hot isostatic pressing, hot pressing or the like is used. A method of obtaining a composite material of metal powder by an extrusion molding method is disclosed in, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Laid-Open No.-208405, there is known a manufacturing method in which a two-layer composite compact is obtained by using two extruders and then sintered to obtain a sintered compact. In addition, JP-A-49-
Japanese Patent No. 22316 discloses a method in which a powder of a tool material and a reinforcing material are put in a cylindrical can and then extruded at a high temperature to obtain a composite material. Further, JP-A-57-98602 discloses a method of compacting a powder with a hot hydrostatic device to obtain a composite material, and JP-A-51-76109 further discloses:
A method of compacting powder with a hot press to obtain a composite material is disclosed. Among these methods, the method described in JP-A-5-208405, which uses the above-described metal powder extrusion apparatus, is capable of easily obtaining a long-sized composite molded article, or the molded article is in a soft state and cut. It is effective because it has the advantage that rough machining can be easily performed in the state of the molded body.

[0003]

There is a need in a wide industrial field for compounding metallic materials. For example, in a screw or the like in which ceramic powder, metal powder, resin, or the like is moved by rotating a screw thread while mixing or kneading, a Co alloy having high wear resistance is arranged on the surface, and an alloy tool having high toughness is provided inside. It is necessary to place steel etc.
In such a case, conventionally, a means by surface treatment such as build-up welding has been mainly adopted, which requires man-hours. There is also a demand for compounding punches having outer edges as cutting edges in order to improve performance and reduce material costs. In addition, in the field of the electric industry, there is a great need for a technique for compounding electrically or magnetically different materials and a new compound material. An example will be described below.

Recently, in the field of dynamo or motor, a synchronous dynamo or motor has been used. For example, the 5th summary of the 1995 National Meeting of the Institute of Electrical Engineers of Japan
According to 29-30, synchronous motor (synchronous motor)
Means that the permanent magnet 21 having the cross section shown in FIG.
Of the permanent magnet embedded type rotor embedded in the core material composed of the non-magnetic material 20 and the layer of the non-magnetic material 20 and the magnetic material 19 using the magnetoresistive effect shown in FIG. A reactance type rotor having a composite structure of layers is known. It is known that the synchronous motor having the rotor shown in FIGS. 6 to 7 does not need a brush or a step ring and is excellent in maintainability and controllability.

In such a synchronous motor, the permanent magnet embedded rotor shown in FIG. 6 has a composite structure in which a non-magnetic layer is formed between adjacent permanent magnets in order to efficiently leak magnetic flux. There is a need to. Further, in the reactance type rotor, in order to form the anisotropy of the magnetic resistance as described in JP-A-6-311677,
As shown in FIG. 7, a composite structure is formed in which a layer of non-magnetic material 20 such as aluminum is formed so as to communicate in an arc shape toward the adjacent convergence areas so that three or more convergence areas are formed on the outer peripheral portion. Is valid.

As described above, a composite structure is required for the rotor of the synchronous motor.
The method obtained by mechanically fixing the composite layer as a separate component as described in No. 1677 has a problem that the manufacturing process becomes complicated. Since the rotors for motors and the like have substantially the same cross section in the longitudinal direction, the present inventor has used two extruders disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-208405 to form a two-layer composite molding. After obtaining the body, the application of a manufacturing method for obtaining a sintered body by sintering was examined. But,
The apparatus described above yields only two-layer composite parts with simple flat plates, which is very unusable for the production of the rotors described above. The object of the present invention is to propose a new metal powder composite material extrusion molding apparatus and metal powder composite material extrusion molding method applicable to the production of the above-mentioned rotor, and also to provide a metal powder composite material suitable for the above-mentioned rotor. It is to provide a binding component.

[0007]

As mentioned above, the manufacture of composite materials having a simple concentric circular cross section and composite materials by a simple flat plate powder metallurgy method has been known. However, as described above, the synchronous motor rotor or the like is required to form a layered or radial composite layer extending from the outer peripheral portion to the inner portion when viewed in cross section. The present invention has been studied in order to satisfy the requirement of the compounding of such a geometrically complicated combination. Then, through the through-hole provided in the composite die used in the extrusion molding method, while passing a kneaded body of the metal powder and the binder to form a predetermined cross section, from the outer peripheral portion of the composite die, in other words, of the composite die From a side surface, a composite kneading body is introduced, and a new method of simultaneously molding the composite kneading body in a slit-shaped space having a predetermined cross section and having a continuous section in the downstream direction of the through hole, and integrating at the exit of the composite die I found it.

As a result, the kneading body formed into the predetermined shape through the through hole and the composite kneading body formed into the predetermined shape through the slit-shaped space are simultaneously extruded by the combination die, A composite molded body can be formed at the exit of the composite die. The slit-shaped space described above supplies the kneading body for compounding from the outer peripheral portion of the compounding die to the inside. Therefore, it is possible to obtain a continuous composite layer from the outer peripheral portion to the inner portion.

That is, the extrusion molding apparatus for a metal powder composite material of the present invention comprises a first extrusion apparatus for extruding a kneaded body of metal powder and a binder toward a compound die, and a kneading body for compounding different from the kneading element. And a second extrusion device for extruding the composite die, wherein the compounding die has through-holes that form the kneading body flow path from the first extruder and the compounding die from the outer peripheral portion toward the central portion. A slit-shaped space that is formed and is continuous in the downstream direction of the through hole, the second extrusion device is connected to the slit-shaped space, and the composite kneading body is extruded into the slit-shaped space. Is.

For example, as the composite die of the present invention, the structure shown in FIG. 2 can be used. 2A is a side view showing an example of the compounding die of the present invention, and FIG.
FIG. 6 is a sectional view taken along the line AA. In FIG. 2B, the kneading body (first kneading body) introduced from the rear side of the drawing is molded in the cross section into the shape of the through hole 2 by the through hole 2 and extruded to the front side of the drawing. On the other hand, the composite kneading body is formed on the outer peripheral portion of the composite die 1.
When the (second kneading body 10) is supplied, the compounding kneading body is filled in the slit-shaped space 3 formed by the outer wall 7 of the through hole 2 and the mandrel 4 shown by the broken line in FIG. While being shaped into a shape, it is pushed forward in the drawing. After passing through the compounding die, the thin outer wall 7 separating the through hole 2 and the slit-shaped space 3 disappears, and the compounded body shown in FIG. 1 is obtained.

Further, in the present invention, the slit-shaped spaces 3 are adjacent to each other in a convergent area so that three or more convergent areas 8 are formed on the outer peripheral portion of the compound die when viewed from the downstream side of the through hole. Can be connected in an arc shape toward. As the compounding die 1 that forms such a slit-shaped space 3, for example, the structure of the compounding die 1 shown in FIG. 5 can be adopted. In FIG. 5, a is a side view showing an example of the compound die of the present invention, and FIG.
FIG. 6 is a sectional view taken along the line AA. In FIG. 5b, the kneading body (first kneading body 9) introduced from the rear of the drawing is the through hole 2
The cross-section is molded into the shape of the through hole 2 and is pushed forward in the drawing. The through-hole 2 is composed of a central through-hole 2a having a star-shaped cross section and an outer peripheral through-hole 2b having an arcuate cross-section, and is formed into each hole shape.

On the other hand, when the composite kneading body (second kneading body 10) is supplied to the outer peripheral portion of the composite die 1, the composite kneading body is introduced into the slit-shaped space 3 by the outer wall 7 of the through hole 2.
This slit-shaped space communicates with adjacent converging regions in an arc shape so as to form four converging regions 8 on the outer peripheral portion of the compounding die, and the compounding mixture is filled therein. Then, it is extruded toward the front of the drawing while being formed into the cross-sectional shape of the slit-shaped space. Then, when passing through the composite die, the thin outer wall 7 separating the through hole 2 and the slit-shaped space 3 disappears, and the composite body shown in FIG. 4 is obtained.

In the present invention, not only the molded body having the shape shown in FIGS. 1 and 4 but also the slit-shaped space may be continuous with the outer peripheral portion of the composite die. It is also possible to obtain such shaped bodies, and to obtain a metal powder composite sintered body corresponding thereto. Further, in the apparatus of the present invention, a pressure-bonding die having a diameter smaller than the opening diameter of the compounding die is provided on the downstream side of the compounding die, and the kneading body and the compounding kneading body are pressure bonded. Is desirable.

Further, the method for molding the composite material of the present invention is, for example, a method carried out by using the above-mentioned molding apparatus of the present invention, in which the kneaded body of the metal powder and the binder is extruded toward the through hole of the die. At the same time, a composite kneading body that is different from the kneading body is extruded from the outer peripheral portion of the die into a slit-shaped space that communicates with the inside thereof, and the composite metal is compounded in the slit shape.

With such an extrusion molding apparatus for a metal powder composite material of the present invention, the cross section has a layered or radial composite region of different metals or different alloys extending inward from the outer peripheral portion, and has a cross section. On the other hand, it is possible to obtain the novel metal powder composite sintered part of the present invention in which the composite region is continuous in the direction of the depth direction.

Further, a kneaded body made of non-magnetic metal powder and a kneaded body made of magnetic metal powder are compounded, and in the composite area and the other area, either one forms a non-magnetic area and the other one forms a magnetic area. If formed, it is possible to form a magnetic path that communicates from the inside to the outer circumference or to form a non-magnetic layer that prevents a short circuit of magnetic flux. Further, as shown in FIG. 4, as a rotor for a reactance type motor that uses magnetic resistance, the composite area has three or more convergence areas (four locations in FIG. 4) in the outer peripheral portion, as shown in FIG. It is assumed that they are connected in an arc shape toward the adjacent convergence areas,
Furthermore, it is preferable to form the composite region in multiple layers.

[0017]

The greatest feature of the metal powder composite sintered part of the present invention is that the part having a layered or radial composite region of dissimilar metals or dissimilar alloys whose section extends inward from the outer periphery is a metal powder. That is, it was obtained as a composite sintered body. That is, the present invention is a metal powder composite sintered body, and since it can be manufactured as an integral body at the time of molding a sintered compact without mechanically compounding, the number of manufacturing steps can be significantly reduced. Furthermore, since they are integrated by sintering, they do not peel off or deform due to inertial force when used as a rotating component such as a rotor for a motor, and thus have excellent safety.

Further, a long product having a cross-sectional shape as shown in FIG. 4 which communicates in an arc shape toward the adjacent converging regions so that three or more converging regions are formed in the outer peripheral portion uses, for example, magnetic resistance. The rotor can be used as a rotor of a reactance motor, and the effect of reducing the number of parts and the number of manufacturing steps is significant as compared with a conventional rotor having a large number of parts.

Further, one of the greatest features of the extrusion molding apparatus of the present invention is that the slit-shaped space formed from the outer peripheral portion toward the central portion is formed in the compound die as described above. . When the slit space is combined with the second extruder, the slit-shaped space is combined with the kneaded body extruded by the first extruder by the second extruder and the kneaded body extruded by the second extruder. . More specifically, the outer wall of the through hole is formed into a thin shape, and by deforming or dividing the outer wall, a slit-shaped space recessed from the outer peripheral portion of the die toward the central portion, for example, the slit-shaped space 3 shown in FIG. , Can be formed. In addition,
In order to supply the mixed body from the second extrusion device to the above-mentioned slit-shaped space to form a composite, the space needs to be a continuous slit-shaped space in the downstream direction of the compounding die.

When the slit-shaped space is viewed from the downstream side of the through hole, for example, as shown in FIG. 4, three or more convergence areas (in FIG. 4, in the outer peripheral portion of the die). 4 places) to divide the through hole,
Moreover, it is possible to form the slit-shaped space in multiple layers. In a composite required to have a cross section shown in FIG. 6 or 7, by extruding a kneading body containing a magnetic powder such as permalloy into the through hole and extruding a non-magnetic powder such as austenitic stainless steel into the slit-shaped space, It is effective as a rotor of a motor.

Further, in the present invention, since the first kneading body and the second kneading body are separately molded, the first kneading body which has passed through the through hole and the second kneading body which has passed through the slit-shaped space are provided. It is desirable to press it sufficiently. This is because if the pressure bonding is insufficient, there is a possibility of peeling during the sintering process after extrusion molding. For example, by providing a pressure bonding die having a diameter smaller than the opening diameter of the compounding die on the downstream side of the compounding die, the kneaded body that has passed through the through-hole and the material that has passed through the slit-shaped space are provided. It becomes possible to perform sufficient pressure bonding. Specifically, for example, with respect to the opening diameter D1 of the composite die 1 shown in FIG. 2, the crimping die 1 in FIG. 3 of the extrusion molding apparatus showing an example of the apparatus of the present invention.
It is preferable that the opening diameter D2 of 8 satisfies the relationship of D1> D2.

[0022]

【Example】

(Embodiment 1) FIG. 2 shows a composite for forming a main part of an extrusion molding apparatus for a metal powder composite material of the present invention for obtaining a rotor core-shaped sintered body for a magnet-embedded synchronous motor shown in FIG. It is a figure which shows an example of the shape of the die 1. In FIG. 2, a is a side view of the composite die 1, and b is AA of the composite die 1.
It is sectional drawing. In the composite die 1, a plurality of through holes 2 forming a kneaded body of the first metal powder and a binder (hereinafter referred to as a first kneaded body 9) are formed by a thin tubular outer wall 7. In FIG. 2B, the kneading body (first kneading body 9) introduced from the rear side of the drawing is molded in the cross-section into the shape of the through hole 2 by the through hole 2 and extruded to the front side of the drawing.

On the other hand, when the compound kneading body (second kneading body 10) is supplied to the outer peripheral portion of the compounding die 1, the slit shape formed by the outer wall 7 of the through hole 2 and the mandrel 4 shown by the broken line in FIG. The space 3 is filled with the composite kneading body, and is extruded forward in the drawing while being shaped into the cross-sectional shape of the slit-shaped space 3. After passing through the compounding die, the thin outer wall 7 separating the through hole 2 and the slit-shaped space 3 disappears, and the compounded body shown in FIG. 1 is obtained. In order to obtain the magnet-embedded synchronous motor rotor core shown in FIG. 1 as a composite, it is necessary to penetrate the magnet hole 5 into which the magnet is inserted and the shaft hole 6 in the center for the shaft. 2 was used in combination with the mandrel 4 shown by the wavy line in FIG.

FIG. 3 shows the composite die 1 shown in FIG. 2 described above.
1 shows a concrete example of an apparatus for extrusion-molding a metal powder composite material of the present invention equipped with. In FIG. 3, the first extrusion device 11 is a device for extruding the first kneading body by the cylinder 12 and the screw 13, and the first kneading body 9
Passes through the first introduction path 14 and passes through the through hole 2 of the compound die 1.
Will be introduced to. The second extrusion device 15 is a device that pushes out the second kneading body 10 by the cylinder 12 and the screw 13, and the second kneading body 10 passes through the second introduction passage 16 formed on the outer periphery of the first introduction passage. Then, it is introduced from the outer periphery of the compounding die 1 into the slit-shaped space 3 of the compounding die 1. As shown in FIG. 3, the compounding die 1 is combined with a mandrel 4 extending to an extrusion port 17 of an extrusion molding device, and a magnet hole 5 and a shaft hole 6 in the center for a shaft are formed. It can be formed. After the composite is molded by the composite die 1 as described above, the pressure bonding die 18 having an opening diameter smaller than that of the composite die 1 provided in the extrusion port 17 located on the downstream side of the composite die 1.
Thus, the pressure is applied and the molding is completed.

Specifically, the metal powder used for the first kneading body is a permalloy powder defined by JIS PC which is a ferromagnetic material, and the non-magnetic austenite powder defined by JIS SUS305 is used as the second kneading body. Using Figure 3
Extrusion was carried out using the above apparatus. At this time, the opening diameter D1 of the die shown in FIG. 2, that is, the diameter of the circumscribed circle of the through hole formed in the compound die 1 is set to 26 mm, and the pressure bonding die 14
The opening diameter D2 was set to 20 mm. The obtained compact was degreased and then sintered at 1220 ° C. in a hydrogen atmosphere. As a result, a composite sintered body having a relative density of 96% and four layers of non-magnetic material shown in FIG. I was able to get it.

(Embodiment 2) FIG. 5 constitutes a main part of an extrusion molding apparatus of a metal powder composite material of the present invention for obtaining a reactance type rotor core-shaped sintered body for a synchronous motor shown in FIG. It is a figure which shows an example of the shape of the composite die 1.
In FIG. 5, a is a side view of the composite die 1, and b is a sectional view of the composite die 1 taken along the line AA. In FIG. 5b, a kneading body introduced from the rear of the drawing will be described with reference to the drawing.
The cross section of the (first kneading body 9) is molded into the shape of the through hole 2 by the through hole 2 and is extruded forward in the drawing. The through hole 2 is
It is composed of a central through hole 2a having a star-shaped cross section and an outer peripheral through hole 2b having an arcuate cross section, and is formed into each hole shape.

On the other hand, when the composite kneading body (the second kneading body 10) is supplied to the outer peripheral portion of the composite die 1, it is formed by the outer wall 7 of the through hole 2, and four converging regions are formed on the outer peripheral portion of the composite die. As shown in FIG. 8, the slit-shaped space 3 communicating with the adjacent converging regions in an arc shape is filled with the kneading body for compounding. Then, it is extruded toward the front of the drawing while being formed into the cross-sectional shape of the slit-shaped space. Then, when passing through the composite die, the thin outer wall 7 separating the through hole 2 and the slit-shaped space 3 disappears, and the composite body shown in FIG. 4 is obtained. That is, by simultaneously extruding the first kneading body and the second kneading body to the compounding die 1, a compound having a laminated structure having an arc-shaped cross section necessary for the reactance type synchronous motor rotor core is formed. is there. As a composite, the slit-shaped space shown in FIG. 4 needs to have a shaft hole 6 formed at the center thereof for the shaft in order to form a reactance type synchronous motor rotor core.
Was used in combination with mandrel 4 shown by the wavy line in FIG.

In the extrusion molding apparatus for metal powder composite material shown in FIG. 3 of the first embodiment, the mandrel 4 is only for the central shaft hole 6 and is replaced with the composite die 1 shown in FIG.
An extrusion molding apparatus for a metal powder composite material for a rotor core for a synchronous motor of the reactance type shown in FIG. Using this apparatus, specifically, the metal powder used for the first kneading body is a permalloy powder defined by JIS PC which is a ferromagnetic material, and the non-magnetic austenite defined by JIS SUS305 is used as the second kneading body. Extrusion was performed using the powder. At this time, the opening diameter D1 of the die shown in FIG. 2, that is, the diameter of the circumscribed circle of the through hole formed in the compound die 1 is set to 26.
mm, the opening diameter D2 of the pressure bonding die 14 was set to 20 mm, and the layer thickness d of the laminated portion was set to 1 mm. The obtained molded body was degreased and then sintered in a hydrogen atmosphere at 1220 ° C. to obtain a density of 9
It was possible to obtain 5% of the composite sintered body shown in FIG.

[0029]

According to the present invention, the combination of the composite materials in the cross section has a complicated shape, for example, the composite area of the layered or radial different metals or different alloys extending inward from the outer peripheral portion, Moreover, it is possible to obtain a part in which the composite region is continuous in the depth direction with respect to the cross section as a metal powder composite sintered body through a simple extrusion molding process. Therefore, it is possible to obtain various tools that require deep formation of a hard layer on the surface, or an electromagnetic material such as a rotor of a synchronous motor that requires a magnetically or electrically complex complex as a sintered integrated product. Become. Therefore, the number of parts and the number of manufacturing steps can be greatly reduced, which is industrially effective, as compared with the conventional method of manufacturing separate parts in advance and mechanically assembling them.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the shape of a metal powder composite sintered part of the present invention.

FIG. 2 is a view showing an example of a compounding die that is a main part of the metal powder compounding extrusion molding apparatus of the present invention.

FIG. 3 is a diagram showing an example of a metal powder composite extrusion molding apparatus of the present invention.

FIG. 4 is a diagram showing another example of the shape of the metal powder composite sintered part of the present invention.

FIG. 5 is a diagram showing another example of a compounding die that is a main part of the metal powder compound extrusion molding apparatus of the present invention.

FIG. 6 is a diagram illustrating a structure of a magnet-embedded rotor core for a synchronous motor.

FIG. 7 is a diagram illustrating a configuration of a reactance type rotor core for a synchronous motor.

FIG. 8 is a diagram showing another example of the shape of the metal powder sintered component of the present invention.

FIG. 9 is a diagram showing another example of the shape of the metal powder sintered component of the present invention.

[Explanation of symbols]

1 compound die, 2 through holes, 3 slit-shaped space,
4 mandrels, 5 magnet holes, 6 shaft holes, 7
Outer wall, 8 Convergence area, 9 First kneading body, 10 Second kneading body, 11 First extrusion device, 12 Cylinder, 13
Screw, 14 first introduction path, 15 second extrusion device,
16 second introduction path, 17 extrusion port, 18 crimping die,
19 magnetic material, 20 non-magnetic material, 21 permanent magnet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical indication location H02K 1/27 501 H02K 21/14 M 21/14 B22F 3/02 P

Claims (10)

[Claims] 1. A cross-section has a layered or radial composite region of different metals or different alloys extending inward from the outer periphery, and the composite region is oriented in the depth direction with respect to the cross-section. A metal powder composite sintered component characterized by being continuous. 2. In the cross section, the composite region is 3 in the outer peripheral portion.
The metal powder composite sintered component according to claim 1, wherein the metal powder composite sintered parts are communicated in an arc shape toward the adjacent convergence regions so as to form convergence regions at more than one place. 3. The metal powder composite sintered component according to claim 1, wherein the composite region is formed in multiple layers. 4. The metal powder composite according to claim 1, wherein one of the composite area and the other area forms a non-magnetic area and the other forms a magnetic area. Sintered parts. 5. A first extruder for extruding a kneaded body of metal powder and a binder toward a compound die, and a second extruder for extruding a compound kneaded body different from the kneader, The compounding die is formed with a through hole that constitutes a kneading body flow path from the first extrusion device, and a slit that is formed from an outer peripheral portion of the compounding die toward a central portion and is continuous in a downstream direction of the through hole. Extrusion molding of a metal powder composite material, characterized in that the second extrusion device is connected to the slit-shaped space, and the composite kneading body is extruded into the slit-shaped space. apparatus. 6. The slit-shaped space has an arcuate shape toward the adjacent convergence areas so that three or more convergence areas are formed on the outer peripheral portion of the compound die when viewed from the downstream side of the through hole. The metal powder composite material extrusion molding apparatus according to claim 5, wherein the metal powder composite material extrusion molding apparatus is connected. 7. The extrusion molding apparatus for metal powder composite material according to claim 5, wherein the slit-shaped space is formed in multiple layers. 8. The metal according to claim 5, further comprising a pressure bonding die having a diameter smaller than an opening diameter of the compounding die, which is provided on the downstream side of the compounding die. Extruder for powder composite materials. 9. A slit in which a kneaded body of metal powder and a binder is extruded toward a through hole of a compound die and a compound kneader different from the kneaded body is communicated with the inside from the outer peripheral portion of the compound die. A method for extrusion-molding a metal powder composite material, which comprises extruding the composite material into a slit-shaped space and compounding the composite kneading body in a slit shape. 10. The method for extrusion molding a metal powder composite material according to claim 9, wherein a composite of non-magnetic metal powder and magnetic metal powder is formed.