JP2002129202A - Apparatus and method for producing sintered product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for producing a sintered product by which the sintered product of high quality can be obtained by using a sintering furnace capable of suppressing the turbulence of the atmosphere in a dewaxing part caused by a gas burner. SOLUTION: At the time of operating the sintering furnace, since gaseous nitrogen is fed from a gas feeding source so as to be allowed to flow from the downstream side toward the upstream side being the carrying-in path of a compact to be sintered in a dewaxing part 11, the gaseous nitrogen does not leak into a preheating chamber 12 or the like on the side lower than the dewaxing part 11 caused by its flame flow or air fed to the gas burner 16 even if the inside of the dewaxing part 11 is heated by a gas burner 16. Further, the combustion gas or the like of a lubricant such as zinc stearate and wax in the compact decomposed by heating is generated in the dewaxing part 11, but the gas can be prevented from leaking into the side of the preheating chamber 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for manufacturing a sintered product using a sintering furnace having an improved dewaxing part.

[0002]

2. Description of the Related Art Generally, in a sintering furnace, when dewaxing gas flows into a combustion chamber, the furnace may be contaminated. And a dewaxing part to be removed. For this reason, the dewaxing portion provided in the sintering furnace is designed to burn or decompose the lubricant in the green compact by heating it and discharge it to the outside of the furnace. FIG. 4 shows one configuration example of such a conventional sintering furnace. In FIG.
Is provided with an endless belt 2. When the molded article is carried into the dewaxing section 3 by driving of the belt 2, the gas burner 4 arranged in the dewaxing section 3 directly heats the molded article. By doing so, the lubricant in the molded article is burned. The dewaxed molded article is then conveyed to the downstream side and sintered through a sintering chamber or the like (not shown) to be a sintered product.

[0003]

However, the above-mentioned prior art uses the gas burner 4 and has an advantage that an energy saving effect can be obtained as compared with the heater type. However, in the above-described conventional technique, when the molded article in the dewaxing portion is heated and dewaxed by the gas burner 4, not only the flame flow by the gas burner 4 is generated but also the air is supplied to the gas burner. Due to the influence of the flame flow and air, the nitrogen gas atmosphere in the dewaxing part is disturbed, and the nitrogen gas not only flows to the high-temperature part downstream of the dewaxing part but also in the molded article decomposed by heating. As a result, a combustion gas of a lubricant such as zinc stearate and waxes also flows, resulting in a problem that a high quality sintered product cannot be obtained.

The present invention has been made in view of the above-mentioned problems of the prior art,
It is an object of the present invention to provide a sintered product manufacturing apparatus and a manufacturing method capable of obtaining a high-quality sintered product using a sintering furnace capable of suppressing a disturbance of an atmosphere in a dewaxing portion due to a gas burner.

[0005]

Means for Solving the Problems To solve the above problems, the present invention employs the following means.

According to the first aspect of the present invention, the article is sintered by sequentially transferring the article to a dewaxing section, a preheating chamber, a sintering chamber, and a cooling zone provided in a sintering furnace. An apparatus for producing a sintered product to be a consolidated product, wherein a nitrogen gas is supplied from a downstream side to an upstream side of the dewaxing part, and a nitrogen gas atmosphere is formed in the dewaxing part by the nitrogen gas. Features. Further, the invention according to claim 2 sinters the molded article by sequentially transporting the molded article to a dewaxing section, a preheating chamber, a sintering chamber, and a cooling zone provided in a sintering furnace. A method for producing a sintered product as a product, wherein a nitrogen gas is supplied from a downstream side to an upstream side of the dewaxing part, and a nitrogen gas atmosphere is formed in the dewaxing part by the nitrogen gas. And

As described above, during the operation of the sintering furnace, the nitrogen gas is sent from the downstream side to the upstream side, which is the carry-in path of the molded article, in the dewaxing section, so that the inside of the dewaxing section is heated by the gas burner. Even so, the nitrogen gas does not leak to the preheating chamber or the like downstream of the dewaxing portion due to the flame flow or the air supplied to the gas burner, and therefore, the adverse effect of the air can be prevented. In addition, in the dewaxing part, combustion gas of lubricants such as zinc stearate and waxes in the molded product decomposed by heating is generated.
It is also possible to prevent the gas from leaking to the preheating chamber side. As a result, the gas in the dewaxing portion does not leak to the high-temperature portion on the downstream side, so that a high-quality sintered product can be obtained, and further, there is no risk that precipitates are generated in the furnace in the high-temperature portion. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus and method for manufacturing a sintered product according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic view showing an example of a production apparatus for implementing a method for producing a sintered product according to the present invention, that is, a sintering furnace, and FIG. 2 is an explanatory sectional view showing a main part of a dewaxing part. An example of the sintering furnace (production apparatus) 10 is applied to, for example, a muffle type mesh belt furnace, and as shown in FIG. The lubricant contained in the molded article is burned,
Next, the molded article itself is heated to a predetermined temperature by passing through the preheating chamber 12 and is further sintered in the sintering chamber 13, and then is passed through the slow cooling section 14 on the downstream side of the sintering chamber 13 to the cooling zone 15. The passage allows a sintered product having predetermined physical / mechanical properties and dimensional accuracy to be obtained. Therefore, the molded article is conveyed from left to right in FIG.
Dewaxing section 11, preheating chamber 12, sintering chamber 13, slow cooling zone 1
4, the cooling zone 15 is sequentially passed.

As shown in FIG. 2, the dewaxing section 11 is provided with a plurality of gas burners 16 for heating the inside to a predetermined temperature. This gas burner 16 is used for the dewaxing part 1.
By heating the inside of 1 to a predetermined temperature, the lubricant in the molded article is burned. Dewaxing part 1
1 is provided with a gas atmosphere forming mechanism that supplies nitrogen (N2) gas from the downstream side of the dewaxing section 11 toward the upstream direction and forms a nitrogen gas atmosphere inside the dewaxing section 11. The gas atmosphere forming mechanism includes a first supply pipe 2 piped to the right in the transport direction (downstream direction) in the dewaxing section 11.
1, a second supply pipe 22 piped on the left side in the transport direction, and a connection pipe 23 connecting the distal end of the first supply pipe 21 and the distal end of the second supply pipe 22 at the downstream end in the dewaxing section 11. When,
And a gas supply source 24 described later. That is,
The first supply pipe 21, the second supply pipe 22, and the connecting pipe 23 form a substantially U-shaped pipe in the dewaxing part 11.
The connection pipe 23 is provided with an ejection port 23a toward the opposite side to the transport direction, that is, toward the upstream side.

As shown in FIG. 3, the base ends of the first supply pipe 21 and the second supply pipe 22 are connected to a gas supply source 24. The gas supply source 24 is configured by polymerizing nitrogen (N2), hydrogen (H2), and methane (CH4) into warm water at 50 to 60C. The analysis values in this case are as follows: CO is 10% by volume, hydrogen is about 15% by volume, and nitrogen is the remaining about 75% by volume. Also, the first
Pumps 25, 25 are provided in the supply pipe 21 and the second supply pipe 22, respectively, so that nitrogen gas can be supplied to the connection pipe 23.

During operation of the sintering furnace, nitrogen gas is supplied to the first supply pipe 2
When the nitrogen gas is sent to the first and second supply pipes 22, the nitrogen gas reaches the connecting pipe 23, and is supplied into the dewaxing part 11 from the ejection port 23a. A nitrogen gas atmosphere is formed. At this time, the nitrogen gas is sent from the downstream side in the dewaxing section 11 to the upstream side, which is the loading path of the molded article, so that the gas in the dewaxing section 11 can be prevented from leaking to the downstream side. Like that.

That is, the gas burner 1
Even when the gas is heated by 6, the flame flow does not cause the nitrogen gas to leak to the downstream side of the dewaxing portion 11, and also the nitrogen gas does not leak due to the air supplied to the gas burner 16. Therefore, it is possible to prevent adverse effects due to the flame flow or air. Moreover, the dewaxing part 11
Inside, a combustion gas of a lubricant such as zinc stearate and wax in the molded article decomposed by heating is also generated, and it is possible to prevent the gas from leaking to the preheating chamber 12 side. As a result, the gas in the dewaxing portion 11 does not leak to the high-temperature portion on the downstream side, so that a high-quality sintered product can be obtained, and a precipitate may be generated in the furnace in the high-temperature portion. Nor.

In the sintering furnace 10, the dewaxing section 11 supplies nitrogen gas from the downstream side to the upstream side into the dewaxing section 11, and creates a nitrogen gas atmosphere in the dewaxing section 11. A gas atmosphere forming mechanism including a first supply pipe 21, a second supply pipe 22, and a connection pipe 23 to be formed, and a gas supply source 24 that supplies nitrogen gas to the first supply pipe 21 and the second supply pipe 22. Therefore, the above-described manufacturing method can be accurately performed. Moreover, a tube for supplying nitrogen gas,
That is, the first supply pipe 21, the second supply pipe 22, and the connection pipe 2
3 can be installed in the dewaxing part 11 with a simple configuration and easily.

According to the apparatus and method for manufacturing a sintered product according to the present embodiment, since the gas atmosphere forming mechanism is configured as described above, the nitrogen gas in the gas supply source 24 is supplied to the dewaxing section 11. A nitrogen gas atmosphere can be formed in the dewaxing part 11. Thereby, the moisture contained in the nitrogen gas promotes the decomposition of zinc stearate in the molded article that is decomposed by heating the gas burner 16,
Since the generation of zinc oxide is further promoted, the degassing action of the molded article can be shortened, and the quality of the product when sintered can be improved.

[0015]

As described above, according to the apparatus and method for manufacturing a sintered product according to the present invention, the nitrogen gas flows from the downstream side in the dewaxing section to the upstream side which is the loading path for the molded article. And a nitrogen gas atmosphere is formed in the dewaxing section in that state, so that it is possible to prevent the gas stream from flowing into the downstream high-temperature section due to the flame flow of the gas burner and the air supplied to the gas burner. It is possible to prevent the combustion gas of lubricants such as zinc stearate and waxes in the molded product decomposed by heating of the molded product from leaking to the preheating chamber side on the downstream side, so that a good quality sintered product can be obtained. There is also an effect that there is no possibility that precipitates are generated in the furnace in the high temperature part.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a sintering furnace, which is one embodiment of a sintered product manufacturing apparatus according to the present invention.

FIG. 2 is an explanatory sectional view showing a main part of a dewaxing part.

FIG. 3 is a piping diagram showing a main part of a gas atmosphere forming mechanism.

FIG. 4 is an explanatory view showing a sintering furnace, which is a conventional sintered product manufacturing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Sintering furnace (production apparatus), 11 ... Dewaxing part, 12 ... Preheating chamber, 13 ... Sintering chamber, 15 ... Cooling zone, 21 ... 1st supply pipe, 22 ... 2nd supply pipe, 23 ... Connecting pipe , 23a: spout, 24: gas supply source

Continued on the front page (72) Inventor Yunori Oguma 3-1-1 Koganecho, Niigata City, Niigata Prefecture Inside Mitsubishi Materials Corporation Niigata Works (72) Inventor Hiroshi Abe 3-1-1 Koganecho, Niigata City, Niigata Prefecture Niigata Works, Mitsubishi Materials Corporation (72) Inventor Norihiko Kawamura 229 Kahata-cho, Tenri-shi, Nara Koyo Thermo System Co., Ltd.F-term (reference) 4K018 DA05 DA33 4K050 AA04 BA02 BA03 BA07 CC07 CC10 4K063 AA07 AA15 BA02 BA03 BA04 BA15 CA03 DA05 DA13

Claims (2)

[Claims] 1. A sintered product having a molded product as a sintered product by sequentially transporting the molded product to a dewaxing section, a preheating chamber, a sintering chamber, and a cooling zone provided in a sintering furnace. A nitrogen gas is supplied from a downstream side to an upstream side of the dewaxing part, and a nitrogen gas atmosphere is formed in the dewaxing part by the nitrogen gas. manufacturing device. 2. A sintered product having a molded product as a sintered product by sequentially transporting the molded product to a dewaxing section, a preheating chamber, a sintering chamber, and a cooling zone provided in a sintering furnace. The method for producing a sintered product, characterized in that a nitrogen gas is supplied from a downstream side to an upstream side of the dewaxing part and a nitrogen gas atmosphere is formed in the dewaxing part by the nitrogen gas. Production method.