JPS6043402A - Production of sintered body having curved part - Google Patents

Abstract

PURPOSE:To produce easily a sintered body having a curved surface along a curved part by molding a powder material for sintering to a plate shape then sintering the molding in the state of disposing the same on a mold having the curved recess. CONSTITUTION:A plate-shaped molding 21 formed by adding a required amt. of a binder, lubricant, etc. according to need to a powder material for sintering and molding the mixture thereof under about 3-7ton/cm<2> pressure is placed on a mold 23 having a curved part consisting of a material such as graphite, refractory brick or the like which does not deform at the sintering temp. and does not react with the molding 21 in the stage of sintering. The molding is then sintered. If the molding 21 has a large thickness, some pressure is exerted preferably in an arrow direction during sintering. The central part of the molding 21 begins to curve downward on progressing of sintering until said part contacts tightly with the curved recess of the mold 23, by which a sintered body 25 having the curved part is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a Dt caking body having a curved portion.

Currently, a small sintered body having a curved part is inserted into a tie (1) and a powder material for sintering is placed on a punch (3) as shown in FIGS. 1 and 2. (5), pressurizes by lowering the upper punch (7) or lowering the upper punch (7) and raising the lower punch (3), and pressurizes the obtained molded body (9). Manufactured by sintering. As can be easily seen from the difference in the filling thickness of the powder material (5) shown in Figure 1, the sintered body obtained by this method has a dense area near the center that is smaller than the density at the edges. Due to this drawback, it cannot be used as mechanical parts that require uniform mechanical properties as a whole. Alternatively, the sintering powder material 0? is inserted onto the lower punch 01i1 inserted into the curved space 0?) extending in the vertical direction in the die Ql) shown as a plan view in FIG. ) and top pashchi Q! Pressure is applied by lowering I or lowering the upper punch OI by F% and raising the lower punch α9, and the obtained molded body is sintered.
II! ! (See also Figure 4). The molded body obtained by this method has the drawback that the powder filling depth is large compared to the wall thickness, resulting in insufficient filling and non-uniform density of the molded body.

The inventor of the present invention, in view of the current situation, has conducted various experiments and research, and has found that a powder material for sintering, which has been formed into a plate shape in advance, is placed on a mold with a predetermined curved surface, and sintered as it is. In this case, it was discovered that the plate-shaped molded product gradually curves downward and finally forms a curved surface that follows the curved surface of the mold, and finally completed the present invention. That is, the present invention is characterized in that the powder material for sintering is formed into a plate shape and then sintered while being placed on a mold having a curved surface to form a curved surface along the curved surface. The present invention relates to a method for manufacturing a sintered body having a curved portion.

The present invention will be described in more detail below with reference to embodiments shown in the drawings.
This will be explained in 11.

In the present invention, as shown in FIG. 5, first, a powder material for sintering is formed into a plate-shaped compact Qυ according to a conventional method, and this is placed on a mold (E) having a curved surface portion. As the powder material for sintering, all known materials can be used.
t, Ft-C, Fe-Cu, Fl-Cu-C,
Fe-N15Ft-Ni-CSFt-Ctt-Ni,
Iron-based materials such as Fz-Cu-Ni-C, Cu, Cu-
Copper-based materials such as 5n-C and other materials, A
An example is one to which at least one of l2O2, SiO2, mullite, etc. is added, and the ton/gti is approximately.

It is also possible to use a binder, a lubricant, etc. as necessary in the same manner as in the conventional method. The thickness of the plate-shaped molded product 041) is not particularly limited, but in the case of a thick-walled product, the advantages of the method of the present invention can be maximized because it can be easily molded in a direction perpendicular to the thickness direction. Advantageously, it is about 1 to 7 am. The mold ring does not deform at the sintering temperature and does not form the molded body Q during sintering.
]) Use a material that does not react with the material, such as graphite or fireproof metal. Alternatively, a reaction prevention coating such as alumina cement may be formed on the surface of a material such as iron that does not deform at the sintering temperature.

Next, the plate-shaped molded body 3υ placed on the mold is sintered according to a conventional method. The sintering temperature varies depending on the type of powder material, etc., but for example, in the case of iron-based materials, it is usually 1150 to 1
Approximately 350℃, usually 750-950℃ for copper-based materials
It is about ℃. The atmosphere during sintering is a neutral or reducing gas atmosphere such as propane converted gas, amperane decomposition gas, nitrogen gas, etc. As the sintering progresses, the center of the molded body Qυ begins to curve downward, and eventually it closely follows the curved surface (%) of the mold (E), and when the shochu is finished, the curved part becomes curved as shown in Figure 6. In addition, when the thickness of the plate-shaped compact 0!] is large, the compact is sintered during sintering, preferably at the beginning, as shown in FIG. Apply some pressure near the center of the QD in the direction of the arrow,
Although not particularly shown in the drawings, when sintering a plate-shaped compact that is relatively long compared to the size of the curved surface of the mold by the method of the present invention, , it is possible to obtain a sintered body that is curved near the center and flat near both ends.

The sintered body obtained according to the present invention may be subjected to an insinta in a conventional manner, if necessary.

The sintered body according to the present invention has a drum play type 10: J
It is extremely useful as wheels, bearings, etc.

Example 1 Cu 80.0% by weight, Sn 3.0wt aS, SiO2
Powdered material for consolidating consisting of 4.0% by weight of graphite and 8.0% by weight of graphite was prepared at a pressure of 4 tons/c4 to a thickness of 4 mm x rlJ.
After being pressure-formed into a plate shape of 25mm x 75mm long, it was placed on a graphite mold with an opening diameter of 60mm on the curved surface, and heated at 850'C in a pff gas atmosphere for 1 hour. L tied.

The obtained sintered body was sized with a pressurizing force of 11 on/d using a round metal mold with a radius of 30 mm.

The physical properties of the thus obtained sintered body having a curved part were as follows.

Density: 5. Of/cIA (uniform throughout) hardness: H
RL66 Anti-fold crab 629#/Cd

[Brief Description of the Drawings] Figures 1 to 4 are cross-sectional views for explaining the conventional method for manufacturing a sintered body having a curved part, and Figures 5 and 6 are 1 is a cross-sectional view for explaining a method of manufacturing a sintered body having a curved portion according to the invention method. (1)...tie, (3)...lower punch, (5)...
・Powder material for sintering, (7)...upper punch, (9)...
・Molded body, Ql)...tie, a frame...concave space, Q time...lower punch, 1η...powder material for sintering, Q
(c) Upper punch, e c... plate-shaped molded body, kiln... mold, (c)... sintered body having a curved part. C or higher) ``!8 valve'' +:= # -* :, 4), zoi・1
Figure 5 23 jN 6 Figure 3

Claims (1)

[Claims] 0) A curved part characterized in that a powder material for sintering is formed into a plate shape and then sintered while being placed on a mold having four curved parts to form a curved surface along the four curved parts. A method for manufacturing a sintered body having