JPS62230903A - Production of tubular billet packed with powder material - Google Patents

Abstract

PURPOSE:To produce a titled billet which is free from longitudinal wrinkles at a low cost by disposing a thin-walled metallic cylinder along the respective peripheral walls of a hermetic vessel consisting of a coaxial cylindrical inside peripheral wall and outside peripheral wall made of rubber, packing a powder material between the metallic cylinders, and subjecting the powder to cold isostatic pressing. CONSTITUTION:A vessel 11 is constituted of the thin inside peripheral wall 1 and outside peripheral wall 2 made of the rubber as well as a bottom wall 3 made of the rubber. The inside cylinder 4 and outside cylinder 5 made of a thin-walled metal are inserted into the vessel 11. The powder material 7 for a billet is packed between the inside cylinder 4 and the outside cylinder 5 and the cylinders are closed by a rubber cap body 8 and are hermetically closed by the inside peripheral wall part 12 and outside peripheral wall part 10 of the cap body 8. The vessel 11 is then pressurized under the prescribed pressure by the cold hydrostatic press. The formed inside tubular molding is taken out of the rubber vessel 11 and an annular metal 14 which is a dummy is positioned to the top end thereof. The inside cylinder 4 and outside cylinder 5 are welded in positions 15, 16 to obtain the billet 17. The powder- packed tubular billet 17 having uniform quality is thereby easily produced at the low cost. The billet 17 is worked by hot extruding to form a pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a powder-filled billet used for manufacturing tubes by hot extrusion pressing.

<Prior Art> As a conventional method for manufacturing this type of billet, it is well known that powder is placed in a rubber container, molded into a tube shape using cold isostatic pressure, and then placed in a tubular capsule to form a billet. . However, in billets made by this method, it is difficult for the powder material molded body to adhere to the inner surface of the capsule, so there is a problem that induction heating is not uniformly performed before processing by hot extrusion press. Furthermore, depending on the type of powder, there is also the problem that the molded body collapses when taken out from the rubber container after cold isostatic pressing. A method that can solve these problems is to fill specially shaped capsules made of thin metal plates with powder and press it with cold isostatic pressure.
It is disclosed in the publication No.-17042.

<Problems to be Solved by the Invention> A problem with the conventional method of using a metal capsule is that when metal plates for encapsulation are encapsulated at both ends of a metal cylinder by welding or other means, the end metal plates do not move in the radial direction of the cylinder. Even if the metal cylinder is compressed by applying isostatic pressure using a cold isostatic press to restrain deformation, the stress distribution during deformation becomes uneven, causing wrinkles in the metal cylinder.

In addition, if the capsule is evacuated before sealing, the increase in the internal pressure of the capsule during hydrostatic pressing will be small, and the frequency of wrinkles will be reduced. There is a risk that the manufacturing cost of powder-filled billets will increase. Furthermore, in addition to the above-mentioned problems, in the method of using a capsule of a special shape, the capsule must be designed in anticipation of changes in the shape of the capsule during cold isostatic pressure, especially deformation of the processed portion of the capsule.

<Means for solving the problem> The means according to the invention provides a seal made of rubber or rubber-like material, consisting of a coaxial cylindrical inner circumferential wall and a cylindrical outer circumferential wall, and a bottom wall and a lid between the inner and outer circumferential walls. A container is used, in which a thin metal cylinder or a malleable metal cylindrical material and a thin metal cylinder are arranged on the inner peripheral wall and the outer peripheral wall, respectively, and between the two thin metal cylinders or with the cylindrical material. A billet powder material consisting of metal powder or a mixture of metal powder and ceramic powder is loaded between the thin metal cylinder as it is or a billet powder material preformed into a cylindrical shape by compression is loaded, and the container is evacuated. The sealed container is pressurized by cold isostatic press to form a tubular body integrating the thin metal cylinder and the powder material, and the tubular body is taken out from the container and sealed. This method is characterized by welding a dummy or a metal material such as a metal plate so as to seal the inner and outer thin metal cylinders at both ends.

<Operation> According to the above method, a thin metal cylinder is placed along at least one of the inner peripheral wall and the outer peripheral wall in a container made of rubber or a rubber-like material, and the powder material for billet is preformed as is or into a cylindrical shape. The container is sealed, and the sealed container is pressurized by cold isostatic press, so that the entire container is reduced approximately uniformly.

That is, a tubular body is obtained in which the tubular space inside the container in a non-pressurized state is reduced in the same direction. At the stage of the tubular body, the thin-walled metal cylinders on the inner and outer surfaces adhere to and enclose the powder portion, and the powder portion does not collapse.

In this method, evacuation is not performed prior to sealing the container, but at least one of the ends does not have a metal plate, so there is no restraint during contraction, so the vertical wrinkles that occur when using a metal capsule are avoided. I can't see it at all.

<Example> Fig. 1 shows the state of the first example of the present invention before cold isostatic pressing, in which 1 is an inner circumferential wall made of relatively thin rubber;
Reference numeral 2 denotes an outer circumferential wall made of relatively thin rubber, and this outer circumferential wall 2 is made lower than the inner circumferential wall 1. Both are adhered to a rubber bottom wall 3 with glue to form a rubber container 11.

An inner cylinder 4 made of thin-walled metal and an outer cylinder 5 also made of thin-walled metal are inserted into the rubber container 11. The outer cylinder 5 is made lower than the inner cylinder 4 for reasons to be described later. The bottoms of the inner tube 4 and the outer tube 5 are closed with a thin metal annular disk 6, but this annular disk 6 may be omitted depending on the case. A powder material 7 is filled between the inner cylinder 4 and the outer cylinder 5. The upper ends of the inner tube 4 and the outer tube 5 are closed with a cover plate 8 made of rubber. As shown in the figure, the lid body 8 has a top plate 9,
An outer circumferential wall portion 10 extends downward from the outer circumferential edge of the upper plate 9 in a perpendicular direction and whose tip portion fits onto the outer circumferential surface of the outer circumferential wall 2; It consists of an extending inner circumferential wall portion 12. Then, the upper end portion 13 of the inner peripheral wall 1
The space between the inner circumferential wall 1 and the inner circumferential wall 12 is sealed by folding it outward and covering the upper end of the inner circumferential wall 11. This sealing work can be done without evacuating the container.
It is carried out in the state of For example, chloroprene rubber is used as the material for the inner circumferential wall 1, outer circumferential wall 2, bottom wall 3, and cover plate 8, and as the powder material 7, suatomized powder of 100 mesh or less is used.

As shown in FIG. 1, a sealed container filled with powder material is pressurized to a predetermined pressure using a cold isostatic press. When the pressure is reduced, gas is discharged from the powder material 7 filled during pressure molding, but this gas flows out between the rubber container and the inner cylinder 4 or outer cylinder 5, and is absorbed there by the bulging deformation of the container. Retained. The internal tubular molded body produced by the pressurization is taken out from the rubber container, and a dummy ring metal 14 is welded to the inner cylinder 4 and outer cylinder 5 at positions 15 and 16, respectively, at the upper end thereof, as shown in FIG. A billet 17 as shown in is obtained.

The reason why the inner cylinder 4 is made higher than the outer cylinder 5 is to facilitate this welding work. This billet 17 is hot extruded to produce a tube.

FIG. 3 shows a second embodiment of the invention, in which lid plates 8 completely similar to the lid plates 8 in the embodiment of FIG. 1 are provided at both ends of the container 11.
1.82. Dummies similar to the dummy 14 in FIG. 1 are welded to both ends of the tubular molded body obtained.

<Effects of the Invention> As mentioned above, in the method of this invention, evacuation is not performed before sealing the container, but at least one of the ends does not have a metal plate, so there is no restraint during contraction, which makes it difficult to use when using a metal capsule. The vertical wrinkles that were observed are not observed at all. In addition, as mentioned above, during compression molding of thin metal cylinders and powder materials, high rigidity that would inhibit deformation at both ends is not used, so the whole is reduced approximately uniformly and maintains a tubular shape. Unlike conventional methods using specially shaped capsules, there is no need to create a specially shaped capsule that anticipates deformation near both ends of the capsule during cold isostatic pressing. Therefore, according to the present invention, a homogeneous powder-filled tubular billet can be manufactured easily and at low cost, which is a great effect.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a container filled with billet material powder for explaining the first embodiment of the present invention, and the second
The figure is a vertical sectional view of a billet obtained by the method of the first embodiment, and FIG. 3 is a vertical sectional view of a billet material powder filled in a container for explaining the second embodiment of the present invention. It is a diagram. 1125...Inner peripheral wall, 2.26...Outer peripheral wall, 3.2
7... Bottom wall, 8.28... Lid plate, 4.22... Thin metal inner cylinder, 5.23... Thin metal outer cylinder, 11.21
... Container, 17.31 ... Billet.

Claims (2)

[Claims] (1) A hermetic container made of rubber or rubber-like material is used, which is composed of a coaxial cylindrical inner circumferential wall, a cylindrical outer circumferential wall, a bottom wall and a lid between the inner and outer circumferential walls, and the inner circumferential wall and A metal cylinder, at least one of which is thin, is arranged along the outer peripheral wall, and a billet powder material is used as it is or a billet powder material preformed into a cylindrical shape by compression is placed between both metal cylinders. After loading, the container is sealed without being evacuated, the sealed container is pressurized by a cold isostatic press to form a tubular body integrating the metal cylinder and the powder material, and the tubular body is taken out from the container. 1. A method for manufacturing a powder material-filled tubular billet, which comprises welding a metal material to seal the exposed end surface of the powder material of the tubular body. (2) A hermetically sealed container consists of an inner circumferential wall and an outer circumferential wall made of relatively thin rubber or rubber-like material, and a lid plate closing between the inner peripheral wall and the outer peripheral wall at at least one end thereof, and the lid The plate includes an upper plate, an outer peripheral wall portion made of relatively thin rubber or rubber-like material that is provided on the outer peripheral edge of the upper plate and that fits on the outer peripheral surface of the outer peripheral wall, and is provided on the inner peripheral edge of the upper plate. A method for manufacturing a powder material-filled tubular billet according to claim 1, characterized in that the billet comprises an inner circumferential wall portion which is connected to the inner circumferential wall in a sealed state.