JPS61221304A - Production of sintered parts - Google Patents

Abstract

PURPOSE:To produce efficiently sintered parts having high quality by erecting plate-shaped green compact moldings, changing properly the direction thereof, lining up plural pieces in tight contact with each other in the thickness direction and pressing both ends thereof with large-sized heat-resistant plates then sintering the moldings. CONSTITUTION:Plural pieces of the plate-shaped green compact moldings 4 are erected on a tray 7 and are brought into tight contact with the thickness direction. These moldings are lined up while the moldings of which the direction is properly changed are grasped. Both ends of the lined-up moldings 4 are grasped and fixed by retaining materials 6 via the heat-resistant plates 5 consisting of ceramics, etc. at the size to cover both ends. The moldings 4 on the tray 7 are put into a furnace and are sintered. The sticking of the moldings 4 to each other is thus prevented without the generation of camber to the moldings 4 at both ends and the sintered parts having high quality are obtd. with high productivity without receiving the limitation of the height in the furnace port.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for manufacturing a sintered part by efficiently sintering a plate-shaped powder compact into a cylindrical quality.

(Technical Background of the Invention) Conventionally, the following method has been known as a method for manufacturing a relatively thin plate-shaped sintered part such as a valve plate for a refrigerator.

(1) As shown in FIG. 1(a), a method in which a plurality of powder compacts 2 are stacked vertically on a tray 1 made of iron, molybdenum, ceramic, etc., and then sintered.

(2) As shown in FIG. 1 (bl), a method of sintering a plurality of powder compacts 2 arranged on a tray 1 and stacking them in multiple stages.

(3) As shown in FIG. 1(c), a plurality of compacted compacts 2 are placed upright on a tray 1, closely aligned in the thickness direction, and both ends are held by pressing materials 3 made of iron or other heat-resistant material. A method of sandwiching and sintering.

(Problems with the Background Art) However, in the above-mentioned conventional method, in method (1), the powder compact 2 on the opposite side of the tray 1 is directly exposed to the flame of the burner in the furnace, so that it is not sintered. There is a disadvantage that the flatness of the finished product becomes poor, and that when stacking multiple pieces vertically, it is limited by the height of the furnace mouth. However, in addition to requiring a large number of trays 1, this method is also limited by the height of the furnace mouth, similar to method (1).

In addition, in the method (3), although there is no restriction due to the height of the furnace mouth, the parts of the powder compact 2 at both ends that have come off the presser material 3 are directly exposed to the burner flame and are warped. The inner few sheets had the disadvantage that their flatness deteriorated, making them unusable, and that the parts stuck together during sintering.

(Objective of the Invention) The present invention has been made in order to eliminate such conventional drawbacks, and aims to provide a method for manufacturing sintered parts in which a plate-shaped powder compact is efficiently sintered with high quality. It is something.

(Summary of the Invention) The present invention provides a method of aligning a plurality of plate-shaped powder compacts by standing them upright and closely aligning them in the thickness direction, aligning them while sandwiching them with appropriate orientations, and applying the powder compacting method to both ends of the compacts. It is characterized by being sandwiched between heat-resistant plates with dimensions that cover the body and sintered between pressers.

Molybdenum or ceramics can be used as the heat-resistant plate.

(Example of the invention) Examples of the present invention will be described below.

Example First, 98 parts by weight of iron powder was mixed with 1 part by weight of graphite powder and 1 part by weight of lithium stearate as a lubricant, and compression molded using a mold at a pressure of about 5 m/cl.
A flat powder compact 4 of 40 pieces x 2.5 pieces was obtained.

The warpage of the powder compact 40 at this time (height of warpage from the flat surface when placed on the flat surface) was 0.04 to 0.06 degrees.

Next, as shown in FIG. 2, about 150 sheets of this compacted compact 4 are stacked upright in the thickness direction while changing the orientation of every 5 to 10 sheets, and both ends are ×2
．． 45×45 through 51 alumina ceramic plates 5
Place it directly on the tray 7 of the furnace with the edge (60 mm Charge it to 1
Sintering was carried out at a temperature of 100° C. for 30 minutes.

The warpage of both end pieces after sintering was 0.05 to 0.08. Moreover, the work of disassembling the material after sintering was easy.

This is thought to be because a minute gap is created in the part where the orientation is changed to prevent them from sticking together during sintering.

On the other hand, when the ceramic plate 5 is not used and the ceramic plate 5 is directly sandwiched and sintered, the warpage of the sintered product at both ends is 0.01 to 0.
．． It was 26-.

(Effects of the Invention) As is clear from the above examples, according to the method of the present invention, the sticking of the products after sintering is reduced, the flatness of both end products after sintering is significantly improved, and workability is improved. Improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the state of sintering of a plate-shaped compacted body by the conventional method, and FIG. 2 is a perspective view showing the state of sintering of the plate-shaped compacted body by the method of the present invention. 1.7...Tray 2.4...Powder compact 3.6...Pressure material 5...Ceramic plate'! f11 Figure 2

Claims (1)

[Claims] 1. When a plurality of plate-shaped powder compacts are stood upright and closely paralleled in the thickness direction, the plates are arranged with appropriate orientations between them, and both ends of the heat-resistant plates are sized to cover the powder compacts. A method for producing a sintered part, characterized by sintering the part by holding it between the holding members.