JPH01208405A - Method and apparatus for working metal powder - Google Patents

Abstract

PURPOSE:To obtain a formed body having complicate shape at high drawing speed by coating fused-state raw material on core wire rod containing the same kind of metal material as the raw material metal powder and extension- forming. CONSTITUTION:The raw material mixing the metal powder with organic polymer, plasticizer and lubricant, kneading and pelletizing, is extruded through a cross head. In this cross head, the core wire rod, which contains the substantially same kind of metal material as the raw material and becomes the same material under sintered condition, is passed through and coated with the fused- state raw material. By this method, the extruded formed body can be prevented from deformation caused by drooping with the dead weight. Further, the core wire rod functions as tension member and even if the formed body is drawn at high speed, the breakage, etc., is not developed. By degleasing and sintering this formed body in a sintering furnace, the sintered product having high quality complicate deformed shape is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a metal powder processing method and apparatus thereof having an extrusion molding step for obtaining a clean molded body by extrusion molding in the process of manufacturing a metal sintered body. The present invention relates to a metal powder processing method and a metal powder processing apparatus including an extrusion molding process of an extrusion molded green body having a complex irregular shape.

[Prior Art] Generally, in the process of manufacturing metal or ceramic products by a sintering method from powder, a green compact before sintering is obtained by compression molding. Since this is usually formed by applying pressure from above and below with a punch, the shape is limited to a relatively simple shape, and the density may become non-uniform inside the molded body. Moreover, since this method is a batch operation, even if an attempt is made to improve productivity, there is a limit due to constraints of various conditions.

On the other hand, in the field of ceramic products such as so-called engineering ceramics, 10 to 20% by weight of an organic binder is added to raw material powder, mixed and kneaded, and then extruded to produce clean compacts with relatively complex shapes. Kudzu is attracting attention as it has begun to be used industrially to produce sintered products efficiently through the binder removal and sintering processes.

Furthermore, with the recent development of mixing, kneading, and extrusion technologies, attempts are being made to apply this technology to metal products as well.

[Problem to be solved by the invention] However, the powder material used in the above-mentioned processing process has a high density because it is filled with metal powder at a high concentration.
When extruded in the horizontal direction, it is easy to deform due to its own weight immediately after being extruded from the die. In order to prevent such deformation of the material, it is possible to make the extruder vertical, or use a crosshead to make the extrusion direction vertical. In the vertical extrusion molding method, post-extrusion processing must be performed between the molding rod and the floor, which limits production speed.

In addition, in the extrusion molding method, the molded product after extrusion is often withdrawn at a constant speed in consideration of the die swell that occurs when the material swells at the so-called opening of the material. The molded body is fragile because it is highly filled with metal powder, and it is not possible to increase the take-up speed of the molded body, which is disadvantageous.

In order to solve the problems pointed out above, the present invention aims to provide a metal powder processing method and a metal powder processing apparatus that have an extrusion molding process for forming a complex irregularly shaped molded body that could not be manufactured using conventional techniques. .

[Means for Solving the Problems] According to the present invention, an extrusion molding step for obtaining a molded body by extruding a raw material obtained by mixing, kneading, and pelletizing metal powder with an organic polymer, a plasticizer, a lubricant, etc.; In a metal powder processing method comprising a sintering step of removing the binder from the molded body and then sintering the molded body to obtain a sintered metal body, the extrusion molding process comprises a compound containing substantially the same substance as the metal powder. A metal powder processing method is obtained, which includes the step of obtaining a molded body by coating the core wire in a molten state with the above-mentioned raw material.

According to the present invention, there is provided a core wire supply device that supplies a core wire containing substantially the same substance as the metal powder, an extruder that heats a raw material containing the metal powder and extrudes it together with the core wire, and the extruder. This extruder has a cooling device that cools the extruded molded product, a take-off device that takes the cooled molded product, and a cutting device that cuts the molded product from the take-up device into a predetermined length. The present invention provides a metal powder processing apparatus characterized by having a crosshead that concentrates and coats a core wire with a raw material.

In other words, the present inventors have studied solutions to the above-mentioned problems, and have developed the present invention by focusing on the fact that if the metal to be made into a sintered body is a material with sufficient ductility and malleability, it can be made into a wire rod. This is what led to the eggplant.

In the present invention, when extruding a raw material obtained by mixing, kneading, and pelletizing metal powder with an organic polymer, a plasticizer, and a lubricant, the fluidized raw material containing a molten binder is extruded through a crosshead. The extruded body is made of a metal powder containing substantially the same type of metal material as the raw material in the crosshead, by passing a core wire made of the same material in a sintered state and coating the core wire. In addition to preventing the core wire from sagging and deforming due to its own weight, the core wire functions as a tension member, so even if the molded body is collected at high speed, it is less likely to be cut, thereby improving productivity. can.

The metal powder processing method of the present invention can be applied not only to a core wire made of a metal that forms a solid solution with raw material powder as a core wire.
The raw material powder is not limited to these, as long as it is a metal that has good wettability in its molten state or has the same coefficient of linear expansion and can be joined.

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

FIG. 1 is a diagram showing an extrusion molding process section of a metal processing apparatus according to an embodiment of the present invention. As shown in this figure, the extrusion molding process consists of a core wire supply device 10 that supplies a core wire, an extruder 20 that coats and extrudes a fluidized raw material onto a core wire 2 supplied by a crosshead 21, and a raw material and this material. A cooling device 30 that cools the molded body extruded together with the core wire coated with the core wire, a take-off device 40 that takes the cooled molded body, and a cutting bag RFT that cuts the taken-off material into a required length. 5
0.

FIG. 2 is a sectional view showing the crosshead portion of the extruder. As shown in the figure, the core wire 2' passing through the core wire holder 22 attached to the base 29 that supplies and stores the raw material is coated with binder or molten raw material in the flow direction indicated by the arrow 24 at the holder outlet 22a. It is discharged from the forming tie 23 located at the tip of the core wire holder to the cooling device.

FIG. 3 is a diagram showing an example of the cross-sectional shape of this molding die 23. As shown in the figure, it has a raw material filling space 25 with a groove-shaped cross section, and a pair of groove-shaped side walls of this space 25. are bent in opposite directions at the upper part, and the cross section of this space 25 is a hexagonal cylinder in which the upper end surfaces of the side walls face parallel to each other. This shows the position where the core wire of the alloy with the same composition as the powder passes. This position is held by the core wire boulder 22 in the figure.The required number of core wires are bundled in advance and placed on the bobbin of the core wire supply device.
(not shown).

A metal powder processing method according to an embodiment of the present invention will be described. Ni 78.5wt% - Fe21.5wt% At this time, a core wire rod of the same material with a diameter of 0.6+wm without a binder was melted from the alloy at the position of x shown in Fig. 3 in a high frequency melting furnace, and then melted using a gas atomization method. It was made into a powder with a uniform particle size of about 10 μl. This powder was kneaded with the composition shown in Table 1 in a pressurized niegu, and then pulverized to obtain a raw material beret.

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

The molded product extruded in this manner is collected at a constant level by the take-off device 40, and therefore has extremely good dimensional stability. Since this molded body is cooled by the cooling device 30, it is not crushed by the take-off device 40, and is cut into the required length by the cutting device 50.

The core wire material used in the extrusion molding process according to the example was 0.
Approximately 4 to 2 diameters are appropriate. However, depending on the device and the shape and size of the sintered body, the diameter of the core wire used may be any value within the above range, but it is 0.4n+
If it is less than m, the strength is small and becomes a problem, and 2, rom
If the gap is too thick, there will be a difference in the density between the surrounding binder and the core wire (bulk), resulting in problems such as the inability to obtain an accurate shape after sintering.

By removing the binder and sintering the molded product having a complex irregular shape obtained as described above in a sintering furnace, a high quality sintered product having a complex irregular shape can be obtained. In addition, in the present invention, the molding tie can be replaced depending on the cross-sectional shape of the molded object, so
A molding die having a cross-sectional shape other than the example may be used.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to efficiently produce a rough-shaped extrusion molded body of a metal sintered product without crushing or other destruction, and the sintering The product has a uniform composition and is of good quality, making it very useful industrially.

[Brief explanation of the drawing]

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

Claims (1)

[Claims] 1. An extrusion molding step of mixing metal powder with an organic polymer, a plasticizer, a lubricant, etc., kneading, and pelletizing the raw material to obtain a molded body, and removing the binder from the molded body, followed by and a sintering step of sintering the metal powder to obtain a sintered metal body, the extrusion molding step includes the step of sintering the metal powder into one or more core wires containing substantially the same type of metal material as the metal powder. A metal powder processing method comprising the step of obtaining a molded body by coating a raw material in a molten state. 2. A core wire supply device that supplies one or more core wires containing substantially the same kind of metal material as the metal powder, and an extruder that heats the raw material containing the metal powder and extrudes it together with the core wire; It has a cooling device that cools the molded product extruded from the extruder, a take-off device that takes the cooled molded product, and a cutting device that cuts the molded product from the take-up device into a predetermined length. . A metal powder processing device, wherein the extruder has a crosshead that concentrates and coats the raw material onto the core wire. 3. The crosshead has a base for supplying and storing the raw material, a core wire holder attached to the base, and a forming die located at the tip of the core wire holder through which the raw material and the core wire pass, and the forming die has a raw material filling space whose cross section penetrates along the raw material passage;
2. The metal powder processing apparatus according to claim 2, wherein the core wire passes through the metal powder processing apparatus.