JPH0689373B2 - Metal powder processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a metal powder processing apparatus having an extrusion molding step of obtaining a green compact by extrusion molding in the step of producing a sintered metal body, and particularly to a complex irregular shape. The present invention relates to a metal powder processing apparatus having an extrusion molding step of a green body.

[Prior Art] Generally, a green compact before sintering is obtained by compression molding in a process of manufacturing a metal or ceramic product from a powder by a sintering method. Since this is usually pressed by a punch in the vertical direction and molded, the shape is limited to a relatively simple shape, and the density may become uneven inside the molded body. Further, since this method is a batch operation, even if it is attempted to improve productivity, there is a limit due to restrictions of various conditions.

On the other hand, in the field of ceramic products centering on so-called engineering ceramics etc., a green molded body of a relatively complicated shape is formed by adding 10 to 20% by weight of an organic binder to raw material powder, mixing and kneading, and then extruding. It is beginning to be industrially carried out to efficiently produce, and to obtain a sintered product through a binder removal and sintering process, and it is getting attention. Further, with the recent development of mixing, kneading and extrusion molding techniques, this technique has been attempted to be applied to metal products.

[Problems to be Solved by the Invention] However, since the powder material used in the above-described processing step is filled with metal powder at a high concentration, the density is large,
When it is extruded in the horizontal direction, it is easily deformed by its own weight immediately after it is extruded from the die. In order to prevent such material deformation, it is conceivable to make the extruder vertical, or to make the extrusion direction vertical by using a crosshead to make the extrusion direction vertical. The vertical extrusion molding method requires post-extrusion processing between the molding die and the floor surface, which limits the production rate. Also, in the extrusion molding method, the molded body after extrusion is often taken at a constant speed in consideration of the die swell in which the material swells at the so-called opening of the material. Is fragile because it is highly filled with metal powder,
It was inconvenient because the take-up speed of the molded body could not be increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal powder processing apparatus for performing an extrusion molding step for molding a complex irregularly shaped molded body which could not be manufactured by the conventional technique in order to solve the above-mentioned problems.

[Means for Solving the Problems] According to the present invention, a core wire supplying device for supplying a core wire containing a substance substantially made of the same material as the metal powder, and a core wire for heating the raw material containing the metal powder. An extruder for extrusion molding with, a cooling device for cooling the molded product extruded from this extruder, a take-up device for taking the cooled molded product, and a molded product from this take-up device to a predetermined length. A metal powder processing apparatus is provided which has a cutting device for cutting, and the extruder has a cross head which concentrates and coats a raw material on a core wire.

That is, as a result of studying the solution to the above-mentioned problems, the present inventors focused on the present invention by paying attention to the point that the metal to be made into a sintered body can be a wire if the material has sufficient ductility and malleability. It was the eggplant.

In the present invention, a metal powder is mixed with an organic polymer, a plasticizer, and a lubricant, kneaded, and when a pelletized raw material is extruded, the binder is melted and the raw material having fluidity is extruded through a crosshead, An extrusion molded body is obtained by carrying out a method of passing a core wire material of the same material in a sintered state containing a metal material substantially the same as the metal powder contained in the raw material in the crosshead and coating the core wire material. It is possible to prevent the core wire material from sagging and deforming due to its own weight, and since the core wire functions as a tension member so to speak, even if the molded body is pulled at a high speed, cutting or the like is less likely to occur, thereby improving productivity.

Incidentally, the metal powder processing method of the present invention is, of course, a core wire made of a metal that produces a raw material powder and a solid solution as the core wire,
The raw material powder is not limited to these as long as it is a metal that is wettable in the molten state or is a bondable metal having an equal linear expansion coefficient.

[Example] An example of the extrusion process according to the present invention will be shown and described in detail.

FIG. 1 is a view showing an extrusion molding process section of a metal working apparatus according to an embodiment of the present invention. As shown in this figure, in the extrusion molding process, the core wire supply device 10 for supplying the core wire material and the crosshead
An extruder 20 for coating the core wire 2 supplied in 21 with a raw material in a fluidized state and extrusion molding, a cooling device 30 for cooling the raw material, the core wire coated with the raw material, and the molded body extruded, and the cooled molding. It has a take-off device 40 for picking up the body and a cutting device 50 for cutting the taken-out material to a required length.

FIG. 2 is a sectional view showing the crosshead portion of the extruder. As shown in the figure, the core wire 2'which penetrates the core holder 22 mounted on the base portion 29 for supplying and storing the raw material is coated with the molten raw material at the holder outlet 22a in the flow direction indicated by the arrow 24. It is discharged from the molding die 23 located at the tip of the core holder to the cooling device.

FIG. 3 is a view showing an example of a groove cross section of the molding die 23, and has a raw material filling space 25 having a groove cross section as shown in FIG.
A pair of groove-shaped side walls of the space portion 25 are bent in a direction facing each other at an upper portion, and a cross section of the space portion 25 has a hexagonal tubular shape having a shape in which upper end surfaces of the side walls face each other in parallel. Is. The X mark in the figure indicates the position through which the core wire made of the alloy having the same composition as the raw material alloy powder passes. This position is held by the core wire holder 22 in the figure. The required number of core wires are bundled in advance and wound on a bobbin (not shown) of the core supply device.

A metal powder processing method according to an embodiment of the present invention will be described. Ni78.5wt% -Fe21.5wt% At this time, 0.6mm of the same material
The core wire without the diameter binder was shown in Fig. 3 x
The alloy at the position was melted in a high-frequency melting furnace and made into powder with an average particle size of about 10 μm by the gas atomizing method. This powder first
The composition shown in the table was kneaded in a pressure kneader and then pulverized to obtain raw material pellets.

This raw material was extruded through a crosshead 21 by an extruder 20 (screw diameter: 30 m / m, L / D: 32) as shown in FIG.

The molded product extruded in this manner is taken by the take-up device 40 at a constant speed, and therefore the dimensional stability is extremely good. Since this molded body is cooled by the cooling device 30, a take-up device
It is not crushed by 40, and the cutting device 50 cuts to a required length.

The core wire used in the extrusion molding process according to the example is 0.4
A diameter of ~ 2mm is suitable. However, depending on the device, the shape and size of the sintered body, the diameter of the core wire used may be any as long as it is within the above range, but if it is 0.4 mm or less, the strength becomes a small problem, and 2 mm or more. If it is too thick, there is a difference in density between the surrounding binder and the core wire material (bulk material), resulting in inconvenience that the finished (sintered) shape cannot be accurately taken.

When the molded product having a complex irregular shape obtained as described above is debindered and sintered in a sintering furnace, a high quality sintered product having a complex irregular shape can be obtained. In the present invention, the molding die can be replaced depending on the cross-sectional shape of the molded body, so that a molding die having a cross-sectional shape other than that of the embodiment can be used.

[Effects of the Invention] As described in detail above, according to the present invention, an extruded product having a complicated shape of a metal sintered product can be efficiently produced without being destroyed by crushing or the like, and the sintered product is uniform. The composition is good in quality and very useful in industry.

[Brief description of drawings]

FIG. 1 is a schematic view showing an extrusion molding process section of a metal powder processing apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a crosshead portion of FIG. 1, and FIG. FIG. 3 is a cross-sectional view showing a die portion of In the figure, 2 is a core wire material, 10 is a core wire supply device, 20 is an extruder, 21 is a crosshead, 22 is a core wire holder, 23 is a molding die, 24 is an arrow indicating the powder raw material supply direction, 25 is a raw material filling space portion, 29 is a crosshead base, 30 is a cooling device, 40 is a take-up device, and 50 is a cutting device.

Claims (2)

[Claims] 1. A core wire supplying device for supplying one or more core wires containing a substance substantially the same as the metal powder, and an extrusion for heating a raw material containing the metal powder to extrude the core wire together with the core wire. Machine, a cooling device for cooling the molded product extruded from the extruder, a take-up device for taking the cooled molded product, and a cutting device for cutting the molded product from the take-up device to a predetermined length And the extruder has a crosshead that concentrates and coats the raw material on the core wire material, and the crosshead supplies the raw material to the base portion for supplying and storing the raw material, and the tip of the core wire holder attached to the base portion. And a forming die through which the raw material and the core wire material pass, and the forming die has a raw material filling space portion whose cross section penetrates along the raw material passage,
A metal powder processing apparatus, wherein one or more core wires penetrate the raw material filling space. 2. The crosshead has a base portion for supplying and storing the raw material, a core wire holder mounted on the base portion, and a molding die at the tip of the core wire holder through which the raw material material and the core wire material pass. A second aspect of the invention is characterized in that the molding die has a raw material filling space portion whose transverse section penetrates along the passage of the raw material, and one or more core wires penetrate the raw material filling space portion.
The metal powder processing apparatus according to claim 5.