JPS61221305A - Production of metallic powder-packed billet - Google Patents

Abstract

PURPOSE:To produce easily a metallic powder-packed billet having a circular cylindrical shape by packing metallic powder or a mixture composed of the metallic powder and ceramic powder into a thin-walled metallic cylinder and pressurizing the same with a cold hydrostatic press in a rubber mold. CONSTITUTION:The thin-walled metallic cylinder 4 having the outside diameter conforming to the inside circumference of a body 2 of the rubber mold 1 for cold hydrostatic pressing consisting of a circular cylindrical body 2 and caps 3, 3 is contained into said body. The powder or the mixture composed of the metallic powder and ceramic powder is vibrated and is packed in this state into the body while the cap 3 is held removed. The cap 3 is then mounted and thereafter the powder is pressurized by the cold hydrostatic press. The cylinder 4 and the powder 5 are thereby compressed and the united cylindrical body 6 is obtd. Metallic disks 7, 7 are welded to both ends thereof and after the inside is deaerated through a pipe 10 for deaeration provided to the disk 7 according to need, the pipe is sealed and the billet 8 is obtd.

Description

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

<Prior Art> As a conventional method for producing this type of billet, it is well known that powder is placed in a rubber container, compressed and solidified using cold isostatic pressure, and then placed in a capsule to form a billet. However, billets made by this method cannot be heated by induction unless the solids are in close contact with the inner surface of the capsule. This requires a period of isostatic pressing. Furthermore, depending on the type of powder, the solidified material may collapse when removed from the rubber container after cold isostatic pressure plating. As another method, Japanese Patent Laid-Open No. 55-65303 discloses a method in which capsules are filled with powder and cold isostatically pressed. This method eliminates the problem of disintegration after consolidation of the powder, but requires specially shaped capsules.

<Problems to be solved by the invention> In the conventional method of using specially shaped capsules, it is necessary to design the capsule by anticipating changes in the shape of the capsule during cold isostatic pressing, especially deformation near both ends. There was an unavoidable problem.

Means for Solving the Problems> The means according to the present invention consists of storing a thin metal cylinder filled with metal powder or a mixture of metal powder and ceramic powder in a cylindrical rubber mold, and filling the cylindrical rubber mold with rubber. This method is characterized in that a lid is attached and a pressure of m is applied by cold isostatic pressing to integrate the thin metal cylinder and its internal powder, and then metal disks are welded to both ends of the cylinder.

<Function> According to the above means, a thin metal cylinder filled with powder is housed in a cylindrical rubber mold, a rubber lid is attached to the mold,
Because it is pressurized using cold isostatic press, the entire product is evenly shrunk. That is, since the thin-walled metal cylinder has almost no directionality in its compressive deformation, it becomes a cylindrical shape together with the internal powder, which has a smaller outer diameter and length than the original cylindrical shape. If corresponding metal disks are welded to each end of the reduced cylindrical shape, it becomes a billet.

Fig. 1 shows a first embodiment, in which 1 is a rubber mold for cold isostatic pressure, which consists of a cylindrical body 2 and a lid 3.3, and has an outer diameter that matches the inner circumference of the body 2. A thin-walled metal cylinder 4 is housed in the main body 2, and with one lid 3 removed, metal powder or a mixture 5 of metal powder and ceramic powder is filled with vibration, and after the lid 3 is attached, it is cooled. Pressurize with a hydrostatic press. The thin metal cylinder 4 and the powder 5 inside are compressed to form an integrated cylindrical body 6.

When metal disks 7.7 are welded to both ends of this cylindrical body 6, a billet 8 as shown in FIG. 4 is completed.

The rubber mold 1 used in the first embodiment had a cylindrical body whose both ends were closed with lids, but as shown in FIG. The rubber mold 1a may be closed, or the rubber mold 1b may be a cylindrical container-like main body 2b closed with a cap-like lid 3b as shown in FIG.

As shown in FIGS. 2 and 3, a thin metal cylinder 4 is inserted and filled with powder 5, a lid 3 or 3b is attached, and a cold
When the lff hydrostatic pressure is applied, a cylindrical body 6 similar to that of the first embodiment is obtained, and when metal disks 7.7 are welded to both ends of the cylindrical body 6,
Billet 8 is completed.

In each of the above embodiments, the powder was filled into a thin metal cylinder inserted into a rubber mold, but in some cases, the powder may be preformed by cold isostatic pressing and then inserted into the thin metal cylinder. This is effective as a measure to prevent wrinkles from occurring on the surface of the billet 8 due to the thin metal cylinder.

Although not explained in the above embodiment, as shown by 10 in FIG. 4, one of the metal discs 7.7 is equipped with a deaeration pipe, and after welding, the inside is deaerated and the pipe is IO may be blocked.

<Effects of the Invention> According to the method of the present invention, during compression molding of powder, the initial outer surface is formed of a thin metal cylinder, which is then compressed to m7xJ in a rubber mold for cold isostatic pressing. Since the entire capsule is compressed uniformly and maintains a cylindrical shape, it is possible to avoid deformation near both ends of the capsule during cold isostatic pressurization, as in the conventional method using capsules. There is no need to create a capsule with a predicted special shape.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a thin metal cylinder and powder contained in a cold isostatic rubber mold used in the first embodiment of the present invention, and FIGS. 2 and 3 are views of other embodiments, respectively. FIG. 4 is a vertical cross-sectional view similar to FIG. 1, and FIG. 4 is a vertical cross-sectional view of the billet obtained in the first embodiment. 1, la, l'b---Rubber mold for cold isostatic pressure, 2.2
a12b...Main body, 3.3b...Lid (rubber), 4.
...Thin metal cylinder, 5...Powder, 7...Metal disk,
8... Billet, lO... Pipe for degassing. Patent applicant: Sanyo Special Steel Co., Ltd. Representative: Tetsu Shimizu and 2 others 1 Figure fz Figure 4

Claims (3)

[Claims] (1) A thin metal cylinder filled with metal powder or a mixture of metal powder and ceramic powder is placed in a cylindrical rubber mold, a rubber lid is attached to the cylindrical rubber mold, and pressure is applied using a cold isostatic press. A method for producing a billet filled with metal powder, characterized in that after the thin metal cylinder and the powder inside thereof are integrated, metal disks are welded to both ends thereof. (2) In claim (1), the metal powder or the mixture of metal powder and ceramic powder filled in the thin metal cylinder is a metal powder-filled billet that has been preformed by cold isostatic pressing. Production method. (3) The method for manufacturing a metal powder-filled billet according to claim (1), wherein one of the metal disks to be welded has a hole for degassing and sealing.