JPS58161701A - Production of sintered body - Google Patents

Abstract

PURPOSE:To enable the production of sintered bodies having high density, dimensional accuracy and strength from raw materials of high m.p. with relatively small load in a short time in the stage of producing the sintered bodies by putting the raw materials into a die having high resistance to heat, and sintering the same while pressurizing the raw materials at a temp. of the m.p. of the raw materials or below. CONSTITUTION:In the stage of sintering single metallic powder of copper or the like or a composite metallic body of carbon powder and steel powder or the like, the raw materials 6 to be sintered are put between a punch 7a and a die 7b manufactured of graphite or ceramics which withstand >=1,500 deg.C and 100kg/ cm<2> load. The assembly is put in a furnace core tube 10, and is heated with a heater 10 at the melting temp. or below of the single metal of the raw material or the low m.p. metal in the composite metallic body and is pressed with a pressurizing bar 1 under the required pressure of 10-100kg/cm<2>, whereby the raw materials are sintered. The sintered body having the density of >=95% to the theoretical density, high dimensional accuracy and strength is produced under small load in a short time without the use of a high temp. sintering method and a hot press method as in the prior art.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sintered body, and its purpose is to provide a manufacturing method different from the high-temperature sintering method and the hot press manufacturing method. Well, load 10
0 & 9/♂ 11 A single metal object or a composite metal object is housed in a highly heat-resistant mold made of graphite or ceramics that can withstand 500℃, and placed in the furnace core tube to maintain high heat resistance throughout the firing and cooling period. Press the iron with a necessary pressure of 10~to'o#/#, and adjust the temperature in the furnace core tube to 80- or more of the melting point of the metal having the lowest melting point, including the melting point of a single metal body or the middle section of a composite metal body, and the melting point. The method is to sinter at the following temperature. There are two types of manufacturing methods: high-temperature sintering and hot pressing. The former high-temperature sintering method requires firing before high-temperature sintering. For example, metal powder, such as copper, is put into a mold and molded at room temperature and high pressure, and the molded product is extruded from the pot and placed in a furnace core tube, and heated to a high temperature, for example 900°C, under no load.
This method produces a sintered body by sintering with 0. This manufacturing method can achieve extremely high density, but products with different thicknesses or complex shapes may be deformed due to sintering shrinkage, resulting in a storm of precision problems. I can't get a good product. Therefore, it is not suitable for products such as mechanical parts that require precision.

In addition, the hot press method does not involve the above-mentioned room temperature and high pressure molding, but instead involves directly putting metal powder into a mold and applying a load of 400 to 1000 io.

Iqi/al, a sintered body is created by firing at a temperature of 600℃ or less.・This manufacturing method does not cause deformation due to shrinkage for items with different thicknesses and rough shapes. Therefore, the dimensional accuracy is good. However, in the case of metals with high melting points, such as copper, -9
Usage: Rarely used, i.e. melting point of copper: 80-
In order to sinter at the above temperature, the melting point is 1083°C, so it must be about 866°C or higher, and when the temperature of the sintered body is raised to 866°C, the mold is deformed and dimensional accuracy cannot be obtained. In addition, if firing is performed at a temperature that does not deform the mold, the density will be low and the result will be a brittle sintered body.Also, even if you make a counterfeit that can withstand this temperature, it will be expensive.Additionally, high pressure loads will be applied. Hydraulic system, for. The structure is complicated and expensive because it is equipped with a pressure follow-up mechanism, etc. Therefore, the present invention was devised to eliminate the above problems, and the method for producing a sintered body according to the present invention will be described below. Examples will be described with reference to the drawings.

The drawing is a cross-sectional view of the sintering furnace. A pressurizing rod l connected to a pressing force generator (not shown) is fitted into the upper cover 2 and passes through the heat-resistant seal 3 into the sintering furnace nose. The hole P# provided in the center of the heat reflecting plate 5 is inserted loosely into the high heat resistant top 1j.
This highly heat-resistant shed 7 m presses the li 7 m with a low pressure load.
17bJc is fitted and pressed. In addition, the high heat-resistant bottom with this concave shape [7b is attached to the top of the stall 7c placed on the lower lid of the sintering furnace. A cooling pipe 8 is wound around l. The sintering furnace 4, which has a built-in highly heat-resistant m7 consisting of an upper 117m and a lower 117b, has a furnace core tube 10 surrounded by a heater 9, and an upper lid 2 that tightly plugs the furnace core tube 1G. and a lower lid 11, and a support stand 1 that supports this lower lid 11.
The top cover 2 is equipped with a thermocouple 13. Gas inlet 14. A cooling pipe 8' connected to a cooling pipe 8 having a pressure rod 1&c is attached, and a gas exhaust port 15 is attached to the lower cover 11.
A cooling pipe 8' connected to a cooling pipe 8' provided in the upper lid 2 is attached. Here, 117 with high heat resistance
is made of graphite or ceramics that can withstand a load of 1 GG kg/cIIL and a temperature of 1500°C.

In the structure of such a sintering furnace, a single metal body, for example, a sintered body 6 of copper powder with a melting point of 1083° C. is heated to 117
b, fit the highly heat-resistant upper mold 7 from the top, fit the pressure rod 1 to the top, and use a pressing force generator to load the load example -1! Multiply 16- by 9/lx”.

Thus, gas is introduced into the sintering furnace nose through the gas inlet 14. Next, when the replacement of air and gas is complete, the heater 9 is turned on.The sintered body 6 is reduced at a temperature of 866°C (80% of the melting point of steel) at the time of sintering. So 2
It is baked for 0 minutes, and when the baking is completed, it is cooled to room temperature.
It is discharged from the sintering furnace nose where the load is applied during firing and throughout the cooling period.

The method for producing a sintered body according to the present invention, which has been described above in accordance with the embodiments, is conventionally l! High heat resistance manufacturing method in which a single metal body such as metal powder, metal fiber, or a composite metal body such as carbon and copper, carbon and nickel, etc. is added without performing room-temperature and high-pressure molding. The highly heat-resistant pot made of graphite or ceramics can withstand a load of 1100 ja/cm and a temperature of 1500°C.The conditions for firing are such that the load area of the hot press method is /z” or more, too #
/cR'' or less, and the limit temperature of the non-metallic material that makes up the sintering furnace is 1600℃, and the limit temperature of the platinum thermocouple that detects the temperature is 1500℃ or less.Furthermore, single metal When sintering a metal body or a composite metal body, it is performed at a temperature of 80° or more of the melting point and less than or equal to the melting point.

In addition, in the present invention, a method of applying a low pressure load to a sintered body,
Whatever the structure and the structure of the sintering furnace at that time, it does not contradict the gist of the present invention.According to the method for producing a sintered body of the present invention, the conventional high-temperature sintering Deformation due to shrinkage that occurs in the manufacturing method is eliminated, and a sintered body with a high melting point that could not be fired using the hot press manufacturing method can be produced.The structure is simple2, making it inexpensive and easy to operate. Now I can do it. It is possible to obtain a theoretical degree of 95 or higher for the sintered body by applying only a slight load to the page and firing for a short time.
Therefore, dimensional accuracy is improved and a sintered body with high strength can be obtained.

[Brief explanation of the drawing]

The drawing shows an embodiment of the method for manufacturing a sintered body according to the present invention, and is a side m1ni showing a schematic cross section of a sintering furnace. S...Sintering furnace, 6...Sintered body, E...
...High heat-resistant type, lO ... Furnace core tube @ Patent applicant Atsushi Doi, Representative of Toyo Denki Manufacturing Co., Ltd.

Claims (1)

[Claims] A single metal body or a composite metal body is housed in a shoe made of graphite or ceramics that can withstand a load of 100 #/# even at a temperature of 1500 tNC, and placed in a furnace core tube, and then heated to 700 °C or higher. 80-80% of the melting point of the single metal body or the melting point of the metal having the lowest melting point contained in the composite metal body.
A method for producing a sintered body, characterized by sintering at a temperature above and below the melting point, and pressing with a necessary pressure of 10 to xoo #/c/ throughout the firing and cooling period.