JP4576331B2 - Continuous sintering furnace - Google Patents

Description

  The present invention provides a continuous sintering furnace in which a setter containing a product to be sintered is guided in the order of at least a burn-off zone, a pre-tropical zone, a sintering zone, and a cooling zone to sinter the product to be sintered. In particular, the temperature in the burn-off zone, the pre-tropical zone, the sintering zone and the cooling zone can be easily set appropriately, and the time for producing the sintered product by sintering the sintered product can be shortened. It is characterized by the fact that it does not increase the size of the equipment and can suppress the mixing of impure gas such as oxygen into the atmosphere gas, and can stably sinter the product to be sintered. It is.

  2. Description of the Related Art Conventionally, sintered products such as automobile parts are manufactured by sintering a sintered product made of a molded product obtained by press-molding metal powder in a sintering furnace.

  And as such a sintering furnace, the setter which accommodated the to-be-sintered article is led at least in order of a burn-off zone, a pretropical zone, a sintering zone, and a cooling zone, and a to-be-sintered article is sintered. A continuous sintering furnace is used.

  Here, as such a continuous sintering furnace, generally, a setter in which a product to be sintered is accommodated is set on a mesh belt, and the setter is sequentially placed in the continuous sintering furnace by the mesh belt. It is made to convey and it guide | induces in order of a burn-off zone | band, a pre-tropical zone, a sintering zone | band, and a cooling zone | band, and it sinters a to-be-sintered article (for example, refer patent documents 1-3).

  Here, when the setter containing the sintered article by the mesh belt is guided in the order of the burn-off zone, the pre-tropical zone, the sintering zone, and the cooling zone, the inlet and outlet in this continuous sintering furnace are always In addition to being in an open state, the belts are in communication with each other without being separated.

  And when each belt | band | zone is in the state where the inlet and outlet in the continuous sintering furnace are always open in this way, outside air enters the continuous sintering furnace from the inlet and outlet of the continuous sintering furnace. There is a possibility that the sintered product obtained by this is colored or deteriorated.

  For this reason, conventionally, the amount of atmospheric gas for sintering supplied to the continuous sintering furnace is generally increased so that outside air can enter the continuous sintering furnace from the inlet and outlet of the continuous sintering furnace. In this case, a large amount of sintering atmosphere gas is required, and a large amount of energy is required to sufficiently heat the sintering atmosphere gas in the sintering zone. There was a problem that the running cost was high.

  In addition, since the zones are in communication with each other as described above, the sintering atmosphere gas heated in the sintering zone flows out to the cooling zone and the temperature of the cooling zone rises. In order to sufficiently cool the sintered product sintered in the cooling zone, it is necessary to lengthen the cooling zone and extend the cooling time, which increases the size of the equipment and makes it possible to manufacture the sintered product. There was a problem that it took a long time.

  In the burn-off zone, generally, a fuel gas is burned by a burner to generate combustion gas and to heat a product to be sintered to decompose a wax component or the like present in the product to be sintered. However, since the zones are in communication with each other as described above, the combustion gas containing the wax component and the like thus decomposed is led to the pretropical zone and the sintered zone, and the obtained sintered product deteriorates. There was a problem. In addition, in order to appropriately heat the article to be sintered in the burn-off zone as described above, it is necessary to adjust the amount of fuel gas burned by the burner, and the amount of generated combustion gas is reduced. There was also a problem that the wax component and the like present in the product could not be sufficiently decomposed.

Furthermore, when the setter containing the sintered product by the mesh belt as described above is guided in the order of the burn-off zone, the pre-tropical zone, the sintered zone, and the cooling zone, the temperature in the sintered zone is generally 1100 ° C. or higher. As a result, the mesh belt gradually grows and needs to be replaced frequently, resulting in high maintenance costs.
Japanese Patent Laid-Open No. 6-172811 Japanese Patent Application Laid-Open No. 11-6001 JP 2002-129202 A

  As described above in the continuous sintering furnace in which the setter containing the article to be sintered is guided in the order of at least the burn-off zone, the pre-tropical zone, the sintering zone, and the cooling zone to sinter the article to be sintered. It is an object to solve a problem.

  That is, the present invention can easily set the temperatures in the burn-off zone, the pre-tropical zone, the sintering zone and the cooling zone in the continuous sintering furnace as described above, and sinter and burn the product to be sintered. The time for producing the product can be shortened, the equipment is not enlarged, and the impurity gas such as oxygen can be suppressed from being mixed into the atmospheric gas, so that the sintered product can be stably sintered. The challenge is to be able to do this.

In the present invention, in order to solve the above-described problems, the setter containing the article to be sintered is guided in order to at least the burn-off zone, the pre-tropical zone, the sintering zone, and the cooling zone in order. In a continuous sintering furnace designed to sinter the product, a feed roller is provided to send a setter to each of the above bands, and at least a heat resistant roller made of a material having high heat resistance is used for the feed roller in the sintered band, A partition door that opens and closes when the setter is moved to the next belt is provided between the belts, a gas supply device that supplies an atmosphere gas for sintering to the cooling belt is provided, and between the belts With the partition door provided in the closed state, a gap is formed between the partition door and the wall surface of each band .

  Here, when the slow cooling zone and the forced cooling zone are provided as the cooling zone, a partition door that opens and closes when the setter is moved between the slow cooling zone and the forced cooling zone is provided. .

  In addition, a vacuum replacement zone is provided following the cooling zone, a gas supply device for supplying the atmosphere gas for sintering is provided in the vacuum replacement zone, and a setter is moved between the cooling zone and the vacuum replacement zone. It is preferable to provide a partition door that opens and closes in some cases.

  Here, when providing a partition door that opens and closes when the setter is moved to the next belt as described above, the entrance-side partition door and the exit-side partition door in each of the bands are simultaneously It is preferable not to open it.

  Moreover, in the continuous sintering furnace in this invention, it is preferable to provide a non-combustion heating device in addition to the burner that generates combustion gas in the burn-off zone.

  In the continuous sintering furnace according to the present invention, it is preferable to continuously feed at least the setter in the above-mentioned sintering band when the setter containing the article to be sintered is conveyed in each band by the feed roller. .

  In the continuous sintering furnace according to the present invention, the setter containing the article to be sintered is guided in order to at least the burn-off zone, the pre-tropical zone, the sintering zone, and the cooling zone by the feed roller to sinter the article to be sintered. When linking, a partition door is provided between the above bands, and the partition door is opened and closed only when the setter is moved to the next band. It is prevented from being guided to each band, and the obtained sintered product is prevented from being colored or deteriorated. For this reason, it is not necessary to increase the amount of the atmosphere gas for sintering supplied into the continuous sintering furnace and sufficiently heat the atmosphere gas for sintering in the sintering zone, and the running cost is reduced.

  Also, as described above, a partition door is provided between the bands, and the partition door is opened and closed only when the setter is moved to the next band. Therefore, the sintering atmosphere heated in the sintering band Gas does not always flow out to the cooling zone, and the temperature of the cooling zone does not rise. Sintering is performed in the sintering zone without extending the cooling zone and extending the cooling time as in the past. The product can be cooled in the cooling zone in a short time, the equipment can be downsized, and the time required for manufacturing the sintered product can be shortened.

  Further, in the continuous sintering furnace according to the present invention, since the heat roller made of a material having high heat resistance is used at least for the feed roller provided in the sintering zone, the heat roller is prevented from being deteriorated by heat. Therefore, stable sintering can be performed over a long period of time, and maintenance costs are reduced.

  Further, in the continuous sintering furnace according to the present invention, as the cooling zone, a slow cooling zone and a forced cooling zone are provided, and a partition door is provided between the slow cooling zone and the forced cooling zone to transfer the setter. If the partition door is opened and closed only in the case, the sintered product sintered in the sintering zone is cooled to a certain temperature in the slow cooling zone, and then the sintered product is put in the forced cooling zone. The product can be cooled rapidly, and the sintered product can be cooled in a shorter time while suppressing the deterioration of the sintered product due to rapid cooling. It is possible to further reduce the time required for the process.

In the continuous sintering furnace according to the present invention, Rutotomoni provided a gas supply device for supplying a sintering atmosphere gas into the cooling zone, in the closed state of the partition door provided between each strip of the Since a gap is formed between the partition door and the wall surface of each band, when the sintering atmosphere gas is supplied to this cooling zone, the sintering atmosphere gas supplied to the cooling zone is sintered, It is guided in the order of the pre-tropical zone and burn-off zone and is discharged outside the furnace, and it is suppressed that the combustion gas containing the wax component generated in the burn-off zone is led to the pre-tropical zone and the sintered zone, and the wax component etc. It is further prevented that the sintered product is deteriorated by the gas containing.

  In addition, a vacuum replacement zone is provided following the cooling zone, a gas supply device for supplying the atmosphere gas for sintering to the vacuum replacement zone is provided, and a partition door is provided between the cooling zone and the vacuum replacement zone. Then, the inside of the vacuum replacement zone is evacuated and the partition door is opened and closed with the sintering atmosphere gas supplied from the gas supply device into the vacuum replacement zone as described above. The sintered body cooled in the cooling zone can be led to this vacuum substitution zone. For this reason, when the partition door is opened and the sintered body cooled from the cooling zone is guided to the vacuum replacement zone, the outside air is prevented from entering the cooling zone.

  In addition, when a partition door is provided between the bands as described above, and the setter is moved to the next band, the partition door on the inlet side and the partition door on the outlet side in each band described above are opened and closed. If they are not opened at the same time, the gas in each band is prevented from flowing into other bands at once, and the temperature change in each band is further suppressed.

  If a non-combustion heating device is provided in addition to the burner that generates combustion gas in the burn-off zone, the combustion gas constant in the burn-off zone can be stably controlled while appropriately controlling the temperature of the burn-off zone. The wax component and the like present in the sintered product can be stably decomposed.

  Further, in the continuous sintering furnace in the present invention, when the setter containing the article to be sintered is conveyed through each band by a feed roller, the setter in the above-mentioned sintered band is continuously fed. Temperature unevenness at the time of sintering with respect to the sintered product accommodated in the setter is suppressed, and generation of distortion or the like in the sintered product is prevented.

  Hereinafter, a continuous sintering furnace according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. In addition, the continuous sintering furnace which concerns on this invention is not limited to what is shown to the following embodiment, In the range which does not change the summary of invention, it can change suitably and can implement.

  In this embodiment, as shown in FIG. 1, a setter 1 in which a plurality of products 2 to be sintered are accommodated is used.

  And in the continuous sintering furnace in this embodiment, the setter 1 which accommodated the some to-be-sintered goods 2 as mentioned above was provided in the entrance 21 of the burn-off zone | band 20 as shown in FIG. 22 to the burn-off zone 20, and the burn-off zone 20 is guided by the feed roller 11 in the order of the pre-tropical zone 30, the sintering zone 40, the cooling zone 50, and the vacuum replacement zone 60 to sinter the article 2 to be sintered. After cooling, the setter 1 is taken out from the outlet door 62 provided at the outlet 61 of the vacuum replacement zone 60.

  Here, in the continuous sintering furnace in this embodiment, the first and second slow cooling zones 51 a and 51 b and the forced cooling zone 52 are provided as the cooling zone 50.

  And as the feed roller 11 provided in the said pre-tropical zone 30, the cooling zone 50, and the vacuum substitution zone 60, what was comprised with heat resistant steel can be used, but in the said sintered zone 40, the temperature is Since it becomes 1100 degreeC or more, as the feed roller 11 provided in the sintering zone 40, the heat resistant roller comprised with carbon-type materials, such as graphite, is used.

  Moreover, in the continuous sintering furnace in this embodiment, between the burn-off zone 20 and the pre-tropical zone 30, between the pre-tropical zone 30 and the sintered zone 40, the sintered zone 40 and the first slow cooling zone 51a, Partition doors 13a to 13e are provided between the second slow cooling zone 51b and the forced cooling zone 52 and between the forced cooling zone 52 and the vacuum replacement zone 60, respectively. Are controlled to open and close when the setter 1 is moved to the next band, and the partition doors 13a, 13b; 13b, 13c; 13c, 13d; 13d, 13e on the inlet side and the outlet side in each band. Are controlled not to open at the same time. In addition, since the partition doors 13b and 13c on the entrance side and the exit side of the sintered band 40 are exposed to a high temperature, it is preferable to use a heat-insulating door with high heat resistance in which ceramic fibers are attached to a carbon composite frame.

  In addition, as described above, between the burn-off zone 20 and the pre-tropical zone 30, between the pre-tropical zone 30 and the sintered zone 40, between the sintered zone 40 and the first annealing zone 51a, and the second annealing zone 51b. As shown in FIG. 3, even when the partition doors 13a to 13d are closed, the partition doors 13a to 13d are provided between the belts 13a to 13d. A gap S is formed without contacting the wall surface, and gas flows through the gap S.

  The burn-off zone 20 is provided with a burner 23 that burns fuel gas to generate combustion gas, and an electrotube heater is provided as a non-combustion heating device 24. The combustion gas is supplied to the gas and the temperature in the burn-off zone 20 is adjusted to about 650 ° C. by the non-combustion heating device 24 described above.

  Further, the pre-tropical zone 30 is provided with the same electrotube heater as the burn-off zone 20 as the non-combustion type heating device 31, and the temperature inside the pre-tropical zone 30 is adjusted to about 820 ° C.

  The sintering zone 40 is provided with a SiC heater as a non-combustion heating device 41, and the temperature in the sintering zone 40 is adjusted to about 1120 ° C.

  Further, the first and second slow cooling zones 51a and 51b are provided with the same electrotube heater as the burn-off zone 20 and the pre-tropical zone 30 as the non-combustion heating device 53, and the first slow cooling zone 51a. In the second slow cooling zone 51b, the temperature is adjusted to about 840 ° C, and in the second slow cooling zone 51b, the temperature is adjusted to about 600 ° C. An inert gas such as nitrogen gas is supplied as a sintering atmosphere gas.

  The forced cooling zone 52 is provided with a circulation fan 54 and a water-cooled cooler 55 to cool the gradually cooled sintered product to about 80 ° C., and the forced cooling zone 52 contains the gas described above. An inert gas such as nitrogen gas is supplied from the supply device 70 as a sintering atmosphere gas.

  The vacuum replacement zone 60 is provided with a vacuum exhaust device 63 for evacuating the inside of the vacuum replacement zone 60, and the vacuum replacement zone 60 is also a sintering atmosphere gas from the gas supply device 70. An inert gas such as nitrogen gas is supplied.

  And in order to sinter the to-be-sintered goods 2 continuously by guide | inducing the setter 1 in which the some to-be-sintered goods 2 were accommodated in the continuous sintering furnace in this embodiment in order as mentioned above, With the partition door 13 a provided between the burn-off zone 20 and the pre-tropical zone 30 closed, the setter 1 in which the article to be sintered 2 is accommodated is introduced into the burn-off zone 20 from the entrance door 22. .

  Then, the setter 1 introduced into the burn-off zone 20 in this manner is intermittently moved sequentially toward the pre-tropical zone 30 by the feed roller 11 and maintained in the burn-off zone 20 for a predetermined time. In this way, the article to be sintered 2 accommodated in the setter 1 is heated to about 650 ° C. by the non-combustion heating device 24 and the combustion gas generated by the burner 23 is acted on to be sintered. The wax component existing in the product 2 is decomposed.

  Here, in the continuous sintering furnace in this embodiment, as described above, the gas supply device 70 is used for sintering to the cooling zone 50 including the first and second slow cooling zones 51a and 51b and the forced cooling zone 52. While supplying atmospheric gas, between the burn-off zone 20 and the pre-tropical zone 30, between the pre-tropical zone 30 and the sintered zone 40, between the sintered zone 40 and the first annealing zone 51a, and the second annealing zone. Since the partition doors 13a to 13d provided between 51b and the forced cooling zone 52 are not in contact with the wall surface of each zone so that the gap S is formed, the sintering atmosphere gas is supplied from the cooling zone 50 side. Through the gap S between the partition doors 13a to 13d and the wall surface of each band, the sintered band 40, the pre-tropical zone 30 and the burn-off band 20 flow in this order. For this reason, in the burn-off zone 20, as described above, even if the wax component or the like existing in the article to be sintered 2 is decomposed and combustion gas containing the decomposed wax component or the like is generated, It is prevented that the sintering atmosphere gas flowing through the gap S leads to the pre-tropical zone 30 and the sintering zone 40.

  Then, when the setter 1 is intermittently moved to the pre-tropical zone 30 side in the burn-off zone 20 as described above and a predetermined time elapses, the entrance door 22 and the partition door between the pre-tropical zone 30 and the sintered zone 40 are used. In the state where 13b is closed, the partition door 13a between the burn-off zone 20 and the pre-tropical zone 30 is opened and closed to move the setter 1 from the burn-off zone 20 to the pre-tropical zone 30.

  Next, the setter 1 guided into the pre-tropical zone 30 is intermittently moved sequentially toward the sintering zone 40 by the feed roller 11 and is maintained in the pre-tropical zone 30 for a predetermined time. In the pre-tropical zone 30, the non-combustion heating device 31 is used to heat the article to be sintered 2 accommodated in the setter 1 to about 820 ° C.

  Then, when the setter 1 is intermittently moved to the sintering zone 40 side in the pre-tropical zone 30 and a predetermined time elapses, the partition door 13a and the sintering zone 40 between the burn-off zone 20 and the pre-tropical zone 30 With the partition door 13c between the first slow cooling zone 51a closed, the partition door 13b between the pre-tropical zone 30 and the sintered zone 40 is opened and closed, and the setter 1 is moved from the pre-tropical zone 30 to the sintered zone. Move to 40.

  Next, the setter 1 guided into the sintering zone 40 in this manner is successively moved to the first slow cooling zone 51a side by the above-mentioned feed roller 11 in order, The sintered product 2 contained in the setter 1 is sufficiently sintered at a temperature of about 1120 ° C. by the non-combustion heating device 41 in the sintering zone 40 for a predetermined time. To do. Here, when the setter 1 guided into the sintered band 40 is moved continuously and sequentially by the feed roller 11, the setter 1 is moved as in the case where the setter 1 is moved intermittently. It is suppressed that the heating conditions by the heating device 41 with respect to each sintered product 2 accommodated in the setter 1 are changed depending on the stop position, and each sintered product 2 accommodated in the setter 1 has the same condition. As a result, the variation in quality of the sintered product and the occurrence of distortion in the sintered product are prevented.

  Then, when the setter 1 is continuously moved to the first annealing zone 51a side in the sintering zone 40 and a predetermined time elapses, the partition door 13b between the pre-tropical zone 30 and the sintering zone 40 and the first 2 With the partition door 13d between the slow cooling zone 51b and the forced cooling zone 52 closed, the partition door 13c between the sintered zone 40 and the first slow cooling zone 51a is opened and closed, and the setter 1 is baked. The band 40 is moved to the first slow cooling band 51a.

  Next, the setter 1 thus guided into the first slow cooling zone 51a is sequentially moved toward the forced cooling zone 52 by the feed roller 11 through the first and second slow cooling zones 51a and 51b. It is moved intermittently and maintained for a predetermined time, and the sintered product sintered as described above is cooled to about 840 ° C. in the first annealing zone 51a, and further in the second annealing zone 51b. Cool to about 600 ° C.

  Then, when the setter 1 is intermittently moved to the forced cooling zone 52 side in the first slow cooling zone 51a and the second slow cooling zone 51b and a predetermined time elapses in this way, the sintered zone 40 and the first slow cooling zone. With the partition door 13c between 51a and the partition door 13e between the forced cooling zone 52 and the vacuum replacement zone 60 closed, the partition door 13d between the second slow cooling zone 51b and the forced cooling zone 52 is The setter 1 is moved from the second slow cooling zone 51b to the forced cooling zone 52 by opening and closing.

  Next, the setter 1 guided into the forced cooling zone 52 in this manner is intermittently moved sequentially toward the vacuum replacement zone 60 by the above-mentioned feed roller 11, and within the forced cooling zone 52 for a predetermined time. The sintered product that has been maintained and gradually cooled in the forced cooling zone 52 as described above is cooled to about 80 ° C. by the action of the circulation fan 54 and the water cooling cooler 55.

  Then, when the setter 1 is intermittently moved to the vacuum replacement zone 60 side in the forced cooling zone 52 and a predetermined time elapses, the partition door 13d between the second slow cooling zone 51b and the forced cooling zone 52 and In the state where the outlet door 62 is closed and the atmosphere gas for sintering is supplied from the gas supply device 70 into the vacuum replacement zone 60, the forced cooling zone 52 and the vacuum replacement zone 60 are The partition door 13e is opened and closed to move the setter 1 from the forced cooling zone 52 to the vacuum replacement zone 60. Thereafter, the outlet door 62 is opened, and the setter 1 guided into the vacuum replacement zone 60 is opened. Is taken out from the outlet 61.

  After the setter 1 is taken out from the vacuum replacement zone 60 in this way, the outlet door 62 is closed, and the outside air that has entered the vacuum replacement zone 60 is evacuated by the vacuum evacuation device 63. Thereafter, the atmosphere gas for sintering is supplied from the gas supply device 70 into the vacuum replacement zone 60.

It is the schematic plan view which showed the state in which the to-be-sintered product sintered by the continuous sintering furnace which concerns on one Embodiment of this invention was accommodated in the setter. It is a schematic explanatory drawing of the continuous sintering furnace which concerns on said embodiment. In the continuous sintering furnace according to the embodiment, between the burn-off zone and the pre-tropical zone, between the pre-tropical zone and the sintered zone, between the sintered zone and the first annealing zone, and between the second annealing zone and the forced zone. It is sectional explanatory drawing which showed a part of the state which closed each partition door provided between cooling zones.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Setter 2 Sintered goods 11 Feed roller 13a-13e Partition door 20 Burn-off zone 21 Inlet 22 Entrance door 23 Burner 24 Heating device 30 Pre-tropical 31 Heating device 40 Sintering zone 41 Heating device 50 Cooling zone 51a 1st slow cooling zone 51b Second slow cooling zone 52 Forced cooling zone 53 Heating device 54 Circulating fan 55 Water cooling cooler 60 Vacuum replacement zone 61 Outlet 62 Outlet door 63 Vacuum exhaust device 70 Gas supply device S Gap

Claims (6)

In a continuous sintering furnace in which the setter containing the product to be sintered is guided in order to at least the burn-off zone, the pre-tropical zone, the sintering zone and the cooling zone to sinter the product to be sintered. In addition, a feed roller that feeds a setter to each of the above bands is provided, and at least the heat roller made of a material having high heat resistance is used as the feed roller in the sintering band, and the above setter is placed between the bands. A partition door that opens and closes when moving is provided , a gas supply device that supplies the atmosphere gas for sintering to the cooling zone is provided, and the partition door provided between the bands is closed. A continuous sintering furnace characterized in that a gap is formed between the door and the wall surface of each band .   The partition door which opens and closes when providing a slow cooling zone and a forced cooling zone in said cooling zone, and transferring a setter between this slow cooling zone and a forced cooling zone in the continuous sintering furnace described in Claim 1 A continuous sintering furnace characterized by comprising: 3. The continuous sintering furnace according to claim 1, wherein a vacuum replacement zone is provided subsequent to the cooling zone, a gas supply device for supplying a sintering atmosphere gas to the vacuum substitution zone is provided, and cooling is performed. A continuous sintering furnace comprising a partition door that opens and closes when a setter is moved between the belt and the vacuum replacement belt . In the continuous sintering furnace described in any one of claims 1 to 3, the partition door on the inlet side and the partition door on the outlet side in each of the bands are prevented from opening simultaneously. Continuous sintering furnace. The continuous sintering furnace according to any one of claims 1 to 4, wherein a non-combustion heating device is provided in the burn-off zone in addition to a burner that generates combustion gas. Continuous sintering furnace. 6. The continuous sintering furnace according to claim 1, wherein the setter is continuously fed by a feed roller in at least the above-described sintering zone .

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