JPH02133377A - Impact sintering and automobile part production device using it - Google Patents

Abstract

PURPOSE:To sinter the material difficult to be sintered without adding any auxiliary additive for sintering by colliding the substance accelerated in a high speed by explosion force against the material to be processed which is preliminarily formed with the fine powder of fine ceramics. CONSTITUTION:When explosive 7 is ignited to make explosion, a piston 13 is moved upward in a high speed by the energy of explosion, and the piston is collided against a die 12 to generate shock waves. The powder 2 is sintered by these shock waves, and the die 12 and a base 14 are moved upward. This ascending speed is adjusted by a throtle 16, and the sintered part is exchanged with new powder and the die and the base are moved downward. After the piston 13 is collided against the die 12, cramp arms 19 is retreated, the lower end of a gun barrel 10 is opened by a motor 18, the piston 13 is moved down to a specified position, explosive is set on the upper surface of a cover body 11, the lower end of the gun barrel io is closed again by the motor 18, and the cramp arms 18 are moved forward to fix the cover body 11 to the gun barrel 10. By exploding the explosive 7, the above-mentioned process is repeated to continuously produce the sintered part.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention involves colliding an object sped up by an explosive force onto a workpiece preformed with fine ceramic powder, thereby impacting the workpiece. The present invention relates to an impact sintering method and apparatus for sintering.

(Prior art) In the conventional sintering method, fine powder of a material is sealed inside a mold and heated to a temperature below the melting point of the material or at which a partial liquid layer is formed, and high pressure is applied from the outside to cause the fine powder to interact with each other. Fix it and mold it into the desired shape. Furthermore, since non-oxides such as silicon nitride and silicon carbide are compounds with strong covalent bonding properties, it is difficult to form a sintered body, so aluminum oxide or the like is added to assist the sintering bond.

(Problem to be Solved by the Invention) In such conventional sintering methods, there is a problem in that as the amount of additives for sintering aid contained in the sintered body increases, the strength characteristics of the sintered body deteriorate. .

Furthermore, since the fine powder is exposed to high temperature and high pressure for a long time, from several minutes to an hour, the powder particle size grows and becomes larger, resulting in a problem in that the strength properties deteriorate.

Furthermore, when materials with different melting points are sintered, there is a problem that the materials with low melting points are thermally denatured, and the materials with high melting points do not completely sinter and bond, resulting in insufficient strength.

The present invention has been made in view of the above points, and when sintering a difficult-to-sinter compact, it is possible to achieve a strong sintering bond without adding bonding aid additives, and without causing material particles to grow. The object of the present invention is to provide an impact sintering method and apparatus that can sinter a mixture of materials with different melting points to form a strong sintered bond without changing the properties of the low melting point materials.

(Means for Solving the Problems) According to the present invention, there is a step of transmitting impact energy generated by an explosive force to a preformed product preformed with fine ceramic powder, and It is possible to provide an impact sintering method and apparatus for manufacturing automobile parts, which comprises a step of sintering fine ceramic fine powders together using internally generated high temperature and high pressure.

(Function) In the impact sintering method and apparatus of the present invention, when sintering a difficult-to-sinter compact, a strong sintering bond can be achieved without adding any bonding aid additives, and without causing material particles to grow. When sintering and sintering a mixture of materials with different melting points, there is an effect of strongly sintering and bonding without changing the properties of the low melting point materials.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram explaining the principle of an example of the method according to the present invention.

In the figure, 1 is a hollow cylindrical body with one end closed, an explosive 7 is disposed inside the closed side of the hollow cylindrical body 1, and a sabot 6 and an impact plate are placed at predetermined positions inside the hollow. 5 are arranged in a connected state. The connected body of the sabot 6 and the impact plate 5 moves in the axial direction of the cylinder. A metal capsule 3 containing powder 2 is disposed inside the open side of the hollow cylindrical body 1, and the metal capsule 3 is placed on the open side of the metal capsule 3.
A momentum trap 4 is arranged so as to be in contact with.

The explosive force of the explosive 7 is transmitted to the sabot 6 and the impact plate 5
The connecting body starts moving at a high speed toward the right side in the figure, that is, toward the open side of the hollow cylindrical body 1. The connected body of the sabot 6 and the impact plate 5 is then accelerated to a speed of several Km/s and collides with the metal capsule 3. The shock wave generated by the collision propagates from the collision surface, that is, the left side, of the metal capsule 3 to the enclosed powder 2, passes to the right side, and is transmitted to the momentum trap 4. When the shock wave passes through the powder 2, high pressure due to the shock wave is applied to the powder 2 at the part where the shock wave is applied, thereby compressing the powder.

Then, since the particles of the powder 2 move at high speed under high pressure, frictional heat is generated between the particles, and the surface of the particles of the powder 2 rapidly becomes high in temperature, and the surface of the particles melts.

As the compression further progresses, the particles become tightly connected to each other.

The thickness of the melting layer on the particle surface is extremely small, and after the shock wave passes through, the particle immediately diffuses heat to the surrounding area and solidifies. Since the temperature reached by the surface layer of the powder particles is extremely high, even if the powder 2 is a hard-to-sinter body of silicon nitride or silicon carbide, the particle surface melts and a strong sintered bond is formed. Furthermore, since the thickness of the melted layer is minute, the heat does not affect the inside of the particles.

Therefore, particles having different melting points can be sintered and bonded to each other. When the shock wave is transmitted from the metal capsule 3 to the momentum trap 4, the momentum trap 4 flies out to the outside.
The shock wave transmitted to the momentum trap 4 becomes a reflected wave and is prevented from propagating to the metal capsule 3 again.

Next, the apparatus according to the present invention will be explained.

FIG. 2 is a block diagram showing one embodiment of the apparatus according to the present invention.

In the figure, 10 is a hollow gun barrel with both ends open, and is installed vertically in the ground with its upper end exposed. A lid 11 for opening and closing the lower end opening of the gun barrel is disposed at the lower end of the gun barrel 10, and a motor 18 for opening and closing is connected to the lid 11. Further, a clamp arm 19 is provided near the lower end of the gun barrel 10 to improve the closure performance and durability when the lid 11 is closed. An explosive 7 made of, for example, TNT gunpowder is installed on the upper surface of the lid 11 inside the gun barrel 10, and a piston 13 that moves in the axial direction of the gun barrel 10 is arranged at a predetermined position inside the gun barrel 10. At the upper end of the gun barrel 10 is a mold 1 which is connected to a stand 14 and which encapsulates powder 2.
2 are arranged. The rigging 14 is connected to a fluid cylinder 15, and the fluid cylinder 15 is provided with a throttle 16 for controlling the rising speed of the rigging 14. Further, a gas vent pipe 20 is connected to the side wall of the gun barrel 10, and the other end of the gas vent pipe 20 communicates with the outside air via a muffler 17.

Next, the operation of the device according to the present invention will be explained.

When the explosive 7 is ignited and exploded, the energy of the explosion causes the piston 13 to rise at high speed.

Then, it collides with the mold 12 and generates a shock wave. The powder 2 is sintered by the shock wave, and both the mold 12 and the table 14 rise. The rate of rise is controlled by the throttle 16, and after replacing the sintered part with fresh powder, it falls again and returns to the state shown in the figure. Also, after the collision between the piston 13 and the mold 12,
The gas caused by the explosion flows out from a hole provided in the side wall of the piston 13 to the gas vent pipe 20, is muffled by the muffler 17, and is then released into the atmosphere. Then, the clamp arm 19 is moved back, the lower end of the gun barrel 10 is opened by the motor 18, the piston 13 is lowered to a predetermined position, and the explosive 7 is placed on the top surface of the lid 11, and the lower end of the gun barrel 10 is closed again by the motor 18. do. Then, the clamp arm 19 is moved forward to fix the lid body 11 and gun barrel 10 together. By detonating the explosive 7, the above action can be repeated and thus successive sintered parts can be produced.

It should be noted that since various different embodiments can be easily constructed without departing from the spirit of the invention, the present invention is not limited to specific embodiments other than the limitations set forth in the claims.

(Effects of the Invention) As explained above, according to the present invention, when sintering a difficult-to-sinter compact, a strong sintering bond can be achieved without adding a bonding aid additive, and material particles can be grown. It is possible to provide an impact sintering method and apparatus that can sinter a mixture of materials with different melting points without causing any melting, and can firmly sinter and bond the low-melting point materials without changing their properties.

[Brief explanation of the drawing]

FIG. 1 is a principle explanatory diagram showing an example of the method according to the present invention;
FIG. 2 is a block diagram showing one embodiment of the apparatus according to the invention. DESCRIPTION OF SYMBOLS 1... Hollow cylindrical body, 2... Powder, 3... Metal capsule, 4... Momentum trap, 5... Impact plate, 6...
...Sabot, 7...Explosives, 10...Cannon barrel, 11...
・Lid body, 12... type, 13... piston, 14...
・Base, 15...Fluid cylinder, 16...Aperture, 17
... Silencer, 18... Motor, 19... Clamp arm, 20... Gas vent pipe.

Claims (4)

[Claims] (1) The step of transmitting the impact energy generated by the explosive force to the preformed product made of fine ceramic powder, and the high temperature and high pressure generated inside the preformed product due to the impact energy cause the fine ceramic powder to be 1. An impact sintering method for manufacturing automobile parts, comprising the step of sintering powders together. (2) The impact sintering method according to claim (1), wherein the fine ceramic is silicon nitride. (3) A hollow cylindrical body with one end closed, a piston disposed at a predetermined position inside the cylindrical body, and a preformed product formed from fine ceramic powder at the open end inside the cylindrical body. 1. An apparatus for manufacturing automobile parts using an impact sintering method, comprising a preform arranging device for arranging preforms, and an explosion means arranged at a closed end inside the cylindrical body. (4) An apparatus for manufacturing automobile parts using the impact sintering method according to claim (3), wherein the fine ceramic is silicon nitride.