JPS61149402A - Molding method of sintered member - Google Patents

Abstract

PURPOSE:To produce efficiently an annular green compact at a low cost by inscribing a porous core with a rotary drum provided with discharge holes, supplying a liquid material contg. pulverous powder into the core and dehydrating said material under high speed rotation. CONSTITUTION:The core 2 of the porous ceramic is installed to inscribe the rotary drum 1 having the discharge holes for liquid and gas on the outside periphery. Filter paper or filter cloth 3 is adhered into single or multiple layers by the liquid to the inside surface of such core 2. The complete powder mixed with various kinds of necessary pulverous powder materials is then suspended in methanol, etc. and is sprayed into the core 2. The powder is dehydrated by rotating the drum 1. The green compact 5 is taken out together with the core 2 after the dehydration and is dried, by which the green compact 5 is obtd. The green compact 5 is subjected to working and sintering to be made into the product having a prescribed size and shape. The large-sized annular product is thus manufactured without using dies and press machine.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention is useful for improving the manufacturing method of cemented carbide, other sintered metals, ceramics, and cermets.

(2) Conventional technology Methods for manufacturing sintered materials containing cemented carbide are broadly classified into cold press method and hot press method.Since the present invention is based on an improvement of the cold press method, the cold press method is used. I will explain about it.

Fill a mold or rubber mold with the finished powder mixed with various necessary fine powder materials, apply high pressure to it to make a powder compact, and then sinter the compact as it is, or perform calcination. It is known that the material is sintered, then molded and then sintered.

Since the present invention relates to an improvement in the green compact production process among the above-mentioned methods for producing sintered products, a further explanation will be given.

Method for manufacturing compacted powder using a mold A predetermined amount of finished powder is placed in a female mold of a predetermined size, a male mold is pushed in, and the compact is iced using a hydraulic press or mechanical press.
After applying a pressure of about 1,000 psi, the green compact is removed from the mold and sintered either directly or after being subjected to appropriate machining. In this case, there are few problems when manufacturing small-sized or simple-shaped products, but a big problem occurs when manufacturing large-sized products, especially ring-shaped products. That is, when a ring-shaped product is to be produced, due to the nature of the green compact, it is necessary to make it solid or to add extremely large extra thickness to the required dimensions. This not only wastes valuable resources, but also obstructs productivity as it requires a large amount of man-hours for the next molding process. Additionally, expensive molds and large presses are required, leading to an increase in production costs.

Method for producing compacted powder using a rubber mold: Fill a specified rubber mold with the finished powder, place it in a pressure-resistant container containing liquid, and apply a liquid pressure of about 1,000 ml per 1c11. After compacting and reducing the pressure, the green compact is removed from the rubber mold.This method has the advantage that the density of the green compact is uniform, but it is difficult to maintain the dimensions of the green compact, and The method of using molds leaves a large amount of excess meat, as well as leaving many problems.

As mentioned above, there are many problems with the known green compact production methods, and improvements are urgently needed in terms of effective use of precious resources, productivity, equipment costs, and floor space, especially in the production of large ring-shaped powder compacts. It's broken.

(3) Problems to be solved by the present invention In the production of large-sized ring-shaped products, for which demand has been increasing recently, the disadvantages of the conventional green compact production method can be eliminated to save valuable resources and increase productivity. The aim is to improve performance and save on invested funds.

(4) Means for Solving the Problems The present invention solves the above-mentioned problems and provides a completely new method for producing a green compact.

The basic idea is to use centrifugal force to obtain a large ring-shaped powder compact.

A porous core with an inner diameter corresponding to the predetermined outer diameter of the powder compact is installed in a cage-shaped rotating body with liquid and gas discharge holes, and the porous core is rotated to complete a predetermined amount of powder. A small amount of slurry in which powder is suspended is injected, the rotation is continued, and after complete dehydration, it is taken out together with the porous core, and the green compact is further removed from the core to obtain a green compact.

As explained in detail, according to the final method, not only is there no need for expensive molds or presses, but also ring-shaped green compacts can be efficiently produced without excess thickness, ie, with less material.

(5) Example of Example An example of manufacturing a ring-shaped green compact having a diameter of 180'', a height of 95'', and a wall thickness of 10'' will be described.

In Figure 1.2.3, (1) is a rotating drum with liquid and gas discharge holes on its outer periphery, and (2) is inscribed in this.
Outer diameter 210'''-9 Height 95'''1. Inner diameter 180
A porous ceramic core is installed in ``1.'' The filter paper or filter cloth shown in (3) is pasted with liquid in one or more layers on the inner surface of the core.
0 order WC94%Co that gives 0 rotation and makes it rotate
A suspension of 4000 g of 6% finished powder in 2000 cc of methanol is injected by spraying.

After injection, the powder is dehydrated for about 2 minutes, and the powder compact is taken out together with the porous core. After drying for several hours, the powder compact is taken out together with the filter paper, and the filter paper is removed to obtain the powder compact.

The obtained green compact can be used as it is, or after pre-sintering, a product with a predetermined shape and size can be obtained by performing slight processing and sintering.

[Brief explanation of the drawing]

The drawings are for explaining the present invention in detail, and FIG. 1 shows a side view, FIG. 2 shows a front view, and FIG. 3 shows a part of a sectional view.

Claims (3)

[Claims] (1) A liquid containing the powder to be sintered is supplied to the inside of a porous core provided inscribed in a rotating drum, the rotating drum is rotated at high speed, and the powder is dehydrated and fixed inside the core. A method for forming a sintered member, characterized by using. (2) A method for molding a sintered member according to claim 1, wherein a filter paper or filter cloth is attached to the inner surface of the core. (3) A method for forming a sintered member according to claim 1 or 2, wherein the powder to be sintered is a cemented carbide powder.