JP4441903B2 - High-speed circulating gas-cooled vacuum heat treatment furnace - Google Patents

Description

  The present invention relates to a high-speed circulating gas cooled vacuum heat treatment furnace.

  The vacuum heat treatment furnace is a heat treatment furnace that heats the product to be treated by refilling with an inert gas after decompressing the inside. The vacuum heat treatment furnace is a heat treatment that does not cause coloration due to moisture because the moisture in the furnace and the processed product after gasification is reduced in pressure after reheating and refilling with inert gas etc. can be completely removed. (Referred to as “bright heat treatment”).

  The gas-cooled vacuum heat treatment furnace has various advantages such as bright heat treatment, no decarburization and carburization, less deformation, and a good working environment. However, the initial gas-cooled vacuum heat treatment furnace has a disadvantage that the cooling rate is insufficient because it is a vacuum cooling type. Therefore, in order to increase the cooling rate, a high-speed circulating gas cooling system has been put into practical use.

  FIG. 4 is a configuration diagram of the high-speed circulating gas cooling furnace disclosed in Non-Patent Document 1. In this figure, 50 is a heat insulating material, 51 is a heater, 52 is an effective working area, 53 is a furnace body and a water cooling jacket, 54 is a heat exchanger, 55 is a turbo fan, 56 is a motor for a fan, 57 is a cooling door, 58 Is a hearth and 59 is a gas distributor.

  In addition, as shown in FIG. 5, the “gas circulation cooling promotion method in a vacuum furnace” of Patent Document 1 includes a heating chamber 66 surrounded by a heat insulating wall 67 in an airtight vacuum vessel 61 and is disposed in the heating chamber. The heated object 64 is heated in vacuum by the heater 62, and the cooler 62 and the fan 63 are provided in the vacuum vessel 61, and the non-oxidizing gas supplied into the vacuum vessel is cooled by the cooler 62. In a vacuum furnace in which gas is circulated into the heating chamber 66 through openings 68 and 69 provided on the opposing heat insulating wall 67 surface of the heating chamber 66 by the rotation of the fan 63 to forcibly circulate and cool the object to be heated 64. The heat-resistant cylindrical hood 65 formed in a divergent shape surrounds the object to be heated 64 placed in the heating chamber 66 at an appropriate interval, and both ends thereof are relative to the openings 68 and 69. Do And sea urchin disposed is obtained so as to circulate the non-oxidizing gas into the heating chamber 66.

Katsuhiro Yamazaki, Vacuum heat treatment of metal materials (2), Heat treatment No.30, No.2, April 1990 Japanese Patent Laid-Open No. 5-230528

The high-speed circulating gas cooling furnaces described in Non-Patent Document 1 and Patent Document 1 have the following problems because heating and cooling are performed in the same place.
(1) The heating heater and the furnace body are at a high temperature at the end of heating, and the heater and the furnace body are also cooled at the same time, so that the heat treatment material cannot be cooled at high speed.
(2) Since there is a heater and a furnace body surrounding the heat treatment material, the cooling gas cannot be supplied uniformly during cooling.
(3) Even in the case of gas cooling alternately in the vertical direction, there is no means for rectifying both the upward and downward cooling gases to a uniform speed and direction, and it has been difficult to reduce distortion of the entire heat treatment material.

  The present invention has been developed to solve the above-described problems. In other words, the object of the present invention is that the heat treatment material can be cooled at a high speed during cooling, the cooling gas can be uniformly supplied to the entire heat treatment material, and the cooling gas is rectified at a uniform speed and direction both upward and downward. An object of the present invention is to provide a high-speed circulating gas-cooled vacuum heat treatment furnace that can reduce distortion of the entire heat treatment material.

According to the present invention, there is provided a high-speed circulating gas cooling vacuum heat treatment furnace having a gas cooling furnace for cooling a heated article to be treated with a pressurized circulation gas, wherein the gas cooling furnace is configured to leave the article to be treated statically. A cooling chamber that surrounds the cooling region to be formed and forms a gas flow path having a constant cross section in the vertical direction, a gas cooling circulation device that cools and circulates the gas passing through the cooling chamber in the vertical direction, and the cooling chamber in the vertical direction A gas direction switching device that alternately switches the direction of the gas passing in the direction, and an upper and lower rectifier that closes the upper and lower ends of the cooling chamber and equalizes the velocity distribution of the gas passing through , the gas direction switching device, A hollow cowling and an elevating cylinder for raising and lowering the cowling. The cowling has a lower suction port that communicates with a lower portion of the cooling chamber at a lowered position, and an upper portion that communicates with an upper portion of the cooling chamber at an elevated position. And a suction port, a high speed circulation gas cooling type vacuum heat treating furnace is provided, characterized in that.
Further, according to the present invention, there is provided a high-speed circulating gas cooling vacuum heat treatment furnace provided with a gas cooling furnace that cools a heated article to be treated with a pressurized circulation gas, the gas cooling furnace comprising: A cooling chamber that surrounds a stationary cooling region and forms a gas passage having a constant cross section in the vertical direction inside the cooling region, a gas cooling circulation device that cools and circulates the gas passing through the cooling chamber in the vertical direction, and the cooling chamber A gas direction switching device that alternately switches the direction of gas passing in the vertical direction, and an upper and lower rectifier that blocks the upper and lower ends of the cooling chamber and equalizes the velocity distribution of the gas passing therethrough, the gas cooling circulation device Comprises a cooling fan that is installed adjacent to the cooling chamber and sucks and pressurizes the gas that has passed through the cooling chamber, and a heat exchanger that indirectly cools the gas sucked into the cooling fan. The heat exchange A hollow cowling that surrounds the container at intervals, and an elevating cylinder that raises and lowers the cowling. The cowling includes a lower suction port that communicates with a lower portion of the cooling chamber in the lowered position, and an upper portion of the cooling chamber in the raised position. A high-speed circulating gas-cooled vacuum heat treatment furnace having an upper suction port communicating therewith is provided.

  According to a preferred embodiment of the present invention, the upper and lower rectifiers are composed of an equal distribution unit and a rectification unit stacked on each other, or have both functions of an equal distribution unit and a rectification unit. A plurality of pressure loss generating means arranged uniformly in a direction orthogonal to the rising gas flow in order to achieve a uniform distribution of the flow velocity by providing a flow path resistance having a flow pressure loss coefficient of 0.1 or more. The section includes a plurality of rectifying grids that rectify the flow direction of the rising gas flow that has passed through the uniform distribution section.

  Furthermore, it is preferable to provide an auxiliary distribution mechanism that guides the direction of gas flow flowing in and out of the cooling chamber above and below the cooling chamber.

  According to the configuration of the present invention, the upper and lower rectifiers block the upper and lower ends of the cooling chamber and uniformize the velocity distribution of the gas passing therethrough, so that the change in the velocity of the gas flow passing through the cooling region can be minimized. The cooling gas with little disturbance can be sprayed on the workpiece. In addition, the outlet after passing through the product to be processed also discharges the cooling gas evenly, thereby exerting a forcible force that allows the cooling gas to pass evenly through the center of the product to be processed. Can be reduced.

Further, the flow velocity distribution can be equalized by the plurality of pressure loss generating means, and the flow direction of the gas flow can be equalized by the plurality of rectifying grids.
Further, by providing an auxiliary distribution mechanism (for example, a blowing plate), even when the upper and lower areas of the cooling chamber are large, the direction of the gas flow toward a plurality of locations can be optimized and the flow can be made more uniform.

  Further, the direction of the gas passing through the cooling chamber in the vertical direction can be alternately switched by alternately communicating the lower suction port and the upper suction port with the suction side of the cooling fan by the gas direction switching device. By this switching, it is possible to reduce the difference in the cooling rate depending on the position of the aligned workpieces and to reduce the distortion of the entire heat treatment material.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is an overall configuration diagram of a high-speed circulating gas-cooled vacuum heat treatment furnace according to the present invention. As shown in this figure, the vacuum heat treatment furnace of the present invention is a multi-chamber heat treatment furnace including a vacuum heating furnace 10, a gas cooling furnace 20, and a moving device 30.
The vacuum heating furnace 10 has a function of heating the product 1 after depressurizing and then refilling with an inert gas or the like. The gas cooling furnace 20 has a function of cooling the heated workpiece 1 with the pressurized circulating gas 2. The moving device 30 has a function of moving the workpiece 1 between the vacuum heating furnace 10 and the gas cooling furnace 20.
The present invention is not limited to a multi-chamber heat treatment furnace, and may be a single-chamber furnace that performs vacuum heating and gas cooling in a single chamber.

  The vacuum heating furnace 10 includes a vacuum vessel 11 in which the inside is evacuated, a heating chamber 12 that houses the article 1 to be processed, a front door 13 for taking the article 1 into and out of the heating chamber, heating It comprises a rear door 14 that closes an opening for moving the object to be processed 1 in the room, a mounting table 15 on which the object 1 to be processed can be horizontally moved back and forth, a heater 16 for heating the object 1 to be processed, and the like. With this configuration, the inside of the vacuum vessel 11 can be decompressed to a vacuum, and the workpiece 1 can be heated to a predetermined temperature by the heater 16.

  The moving device 30 includes a conveying rod 32 that horizontally moves the article 1 to be processed between the vacuum heating furnace 10 and the gas cooling furnace 20, a rear door elevating device 33 that elevates and lowers the rear door 14, and a front door 13. A front door lifting / lowering device 34 that opens and closes and opens / closes and an intermediate door lifting / lowering device 34 that lifts and lowers and opens / closes the intermediate heat insulating door 21a of the gas cooling furnace 20 are provided. In this example, the transport bar 32 is a rack and pinion drive, the rear door lifting device 33 is a linear cylinder, and the front door lifting device 34 and the intermediate door lifting device 34 are hoisting machines. However, the present invention is not limited to this, The drive mechanism may be used. With this configuration, the article 1 to be processed is moved horizontally between the vacuum heating furnace 10 and the gas cooling furnace 20 by the transfer rod 32 with the rear door 14, the front door 13 and the intermediate heat insulating door 21a opened. Can do.

2 is a partially enlarged view of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 1 to 3, the gas cooling furnace 20 includes a vacuum vessel 21, a cooling chamber 22, a gas cooling circulation device 24, a gas direction switching device 26, and a rectifier 28.
The vacuum vessel 21 accommodates an intermediate heat insulating door 21 a provided to face the front door 13 of the vacuum heating furnace 10, a cylindrical vessel body 21 b that accommodates the article 1 to be processed, and a gas cooling and circulation device 24. It consists of a circulating portion 21c and clutch rings 21d and 21e that can be opened and closed in an airtight manner. With this configuration, the workpiece 1 can be stored directly in the container body 21b by opening the clutch ring 21e and retracting the circulation part 21c to the right in FIG. 1 from the container body 21b. Further, the intermediate heat insulating door 21a and the circulating portion 21c are hermetically connected to the container body 21b by the clutch rings 21d and 21e, and pressurized cooling gas (argon, helium, nitrogen, hydrogen, etc.) is supplied to the inside. , Pressurized gas can be used for cooling.

The cooling chamber 22 is provided adjacent to the vacuum heating furnace 10 in the central portion of the container body portion 21b. The vacuum heating furnace side of the cooling chamber 22 is partitioned by an intermediate heat insulating door 21a, and the gas cooling circulation device and both side surfaces are partitioned by airtight heat insulating walls 22a and 22b. The cooling chamber 22 is open at the upper and lower ends, and forms a gas flow path having a constant cross section in the vertical direction inside thereof. The inside of the cooling chamber 22 is a cooling region, and the object to be processed 1 is a small metal part such as a moving blade, a stationary blade, or a bolt of a gear / shaft jet engine, and is accommodated in a tray or a basket. In the center of 22, the air is placed on a mounting table 23 having air permeability.
The mounting table 23 is installed at the same height as the mounting table 15 of the vacuum heating furnace 10 and can freely move on the built-in roller. Further, as shown in FIG. 3, a horizontal partition plate 22 c is provided between the container body 21 b and the heat insulating wall 22 b to partition the gas located above and below the cooling chamber 22 in an airtight manner.

The gas cooling / circulation device 24 is installed adjacent to the cooling chamber 22 and sucks and pressurizes the gas that has passed through the cooling chamber 22, and a heat exchanger 25 that indirectly cools the gas sucked into the cooling fan 24a. It consists of. The cooling fan 24a is rotationally driven by a cooling fan motor 24b attached to the circulation part 21c of the vacuum vessel 21, and sucks gas from the central part and discharges it from the outer peripheral part. The heat exchanger 25 is, for example, a cooling fin tube that is water-cooled inside.
With this configuration, the circulating gas cooled by the heat exchanger 25 can be sucked from the central portion, and the gas passing through the cooling chamber 22 discharged from the outer peripheral portion in the vertical direction can be cooled and circulated.

  In this example, the gas direction switching device 26 includes a hollow cowling 26a that surrounds the heat exchanger 25 at an interval, and an elevating cylinder 27 that moves the cowling 26a up and down. The cowling 26a has a lower suction port 26b that communicates with the lower portion of the cooling chamber 22 at the lowered position, and an upper suction port 26c that communicates with the upper portion of the cooling chamber 22 at the elevated position.

  With this configuration, the gas direction switching device 26 alternately connects the lower suction port 26b and the upper suction port 26c to the suction side of the cooling fan 24a, thereby alternately changing the direction of the gas passing through the cooling chamber 22 in the vertical direction. The difference in the cooling rate depending on the position of the workpieces to be switched and aligned is reduced, and the distortion of the entire heat treatment material is reduced.

The rectifier 28 is provided above and below the upper and lower ends of the cooling chamber 22, and has a function of making the velocity distribution of the gas passing through the cooling chamber 22 uniform.
The upper and lower rectifiers 28 are composed of an equal distribution unit 28a and a rectification unit 28b stacked on each other. Note that the rectifier 28 may have both functions of an equal distribution unit and a rectification unit.
The uniform distribution section 28a is evenly distributed in the direction perpendicular to the gas flow 2 (in this example, in the horizontal direction) in order to achieve uniform distribution of the flow velocity by providing a flow resistance having a pressure loss coefficient of 0.1 or more of the gas flow. It has a plurality of pressure loss generating means arranged. The pressure loss generating means is, for example, a through hole, and the flow velocity is evenly distributed by adding flow resistance. The higher the ratio of the gas flow 2 to the total pressure loss, the higher the effect of uniform distribution, and the higher the flow resistance (pressure loss) of the upper and lower pressure loss generating means, the higher the pressure resistance of the gas flow 2 Set the coefficient to 0.1 or more.
Note that there is a relationship of the formula (1) among the pressure loss coefficient ζ, the loss head h, the flow velocity V, and the gravitational acceleration g.
h = ζ · V ² / (2 · g) (1)

The rectification unit 28b is composed of, for example, a plurality of rectification grids arranged in a lattice pattern, and rectifies the flow direction of the gas flow 2 that has passed through the uniform distribution unit 28b to equalize the flow direction.
With this configuration, the flow velocity distribution is equalized by a plurality of pressure loss generating means, and the flow direction of the gas flow is equalized by a plurality of rectifying grids.

  In addition, the high-speed circulating gas-cooled vacuum heat treatment furnace of the present invention is provided with auxiliary distribution mechanisms 29 (for example, blow-in plates) that guide the direction of gas flow flowing in and out of the cooling chamber above and below the cooling chamber 22. Even when the area is large, the direction of the gas flow toward a plurality of locations is optimized to improve the flow uniformity.

  According to the above configuration of the present invention, the upper and lower rectifiers 28 block the upper and lower ends of the cooling chamber 22 and uniformize the velocity distribution of the gas passing therethrough, so that the change in the velocity of the gas flow passing through the cooling region is minimized. It is possible to suppress the cooling gas with less turbulence to the workpiece. Further, the outlet after passing through the article to be processed 1 also discharges the cooling gas evenly, thereby exerting a forcing force that allows the cooling gas to pass evenly through the central part of the article to be processed. Distortion can be reduced.

  As described above, the high-speed circulating gas-cooled vacuum heat treatment furnace of the present invention can rapidly cool the heat-treated material during cooling, can uniformly supply the cooling gas to the entire heat-treated material, and can be cooled both upward and downward. It has excellent effects such as that the gas can be rectified at a uniform speed and direction to reduce distortion of the entire heat treatment material.

  In addition, this invention is not limited to the Example mentioned above, Of course, unless it deviates from the summary of this invention, it can change freely.

1 is an overall configuration diagram of a high-speed circulating gas cooled vacuum heat treatment furnace according to the present invention. It is the elements on larger scale of FIG. It is sectional drawing in the AA of FIG. 1 is a configuration diagram of a fast circulating gas cooling furnace disclosed in Non-Patent Document 1. FIG. 1 is a configuration diagram of “a gas circulation cooling promotion method in a vacuum furnace” of Patent Document 1. FIG.

Explanation of symbols

1 Product to be treated, 2 Circulating gas,
10 vacuum heating furnace, 11 vacuum vessel, 12 heating chamber,
13 front door, 14 rear door, 15 mounting table, 16 heater,
20 gas-cooled furnace, 21 vacuum vessel,
21a Intermediate heat insulation door, 21b Container body,
21c circulation part, 21d, 21e clutch ring,
22 cooling chamber, 22a, 22b heat insulation wall, 22c horizontal partition plate,
24 gas cooling circulation device, 24a cooling fan,
24b cooling fan motor, 25 heat exchanger,
26 gas direction switching device, 26a cowling,
26b Lower suction port, 26c Upper suction port, 27 Lift cylinder
28 rectifier, 28a equal distribution part, 28b rectification part,
29 Auxiliary distribution mechanism, 30 moving device, 32 transport rod,
33 Rear door lifting device, 34 Front door lifting device,
34 Intermediate door lifting device

Claims (4)

A high-speed circulating gas cooling vacuum heat treatment furnace equipped with a gas cooling furnace that cools a heated workpiece with a pressurized circulating gas,
The gas cooling furnace cools a gas passing through the cooling chamber in a vertical direction, and a cooling chamber that surrounds a cooling region in which the article to be processed is placed and forms a gas flow path having a constant cross section in the vertical direction. Circulating gas cooling circulation device, gas direction switching device that alternately switches the direction of gas passing in the vertical direction in the cooling chamber, and upper and lower rectifiers that equalize the velocity distribution of the gas passing through the upper and lower ends of the cooling chamber and, with a,
The gas direction switching device includes a hollow cowling and an elevating cylinder that raises and lowers the cowling. The cowling includes a lower suction port that communicates with a lower portion of the cooling chamber at a lowered position, and an upper portion of the cooling chamber at an elevated position. A high-speed circulation gas-cooled vacuum heat treatment furnace having an upper suction port communicating therewith . A high-speed circulating gas cooling vacuum heat treatment furnace equipped with a gas cooling furnace that cools a heated workpiece with a pressurized circulating gas,
The gas cooling furnace cools a gas passing through the cooling chamber in a vertical direction, and a cooling chamber that surrounds a cooling region in which the article to be processed is placed and forms a gas flow path having a constant cross section in the vertical direction. Circulating gas cooling circulation device, gas direction switching device that alternately switches the direction of gas passing in the vertical direction in the cooling chamber, and upper and lower rectifiers that equalize the velocity distribution of the gas passing through the upper and lower ends of the cooling chamber and, with a,
The gas cooling / circulating device comprises a cooling fan that is installed adjacent to the cooling chamber and sucks and pressurizes the gas that has passed through the cooling chamber, and a heat exchanger that indirectly cools the gas sucked into the cooling fan,
The gas direction switching device includes a hollow cowling that surrounds the heat exchanger at an interval, and a lift cylinder that lifts and lowers the cowling, and the cowling communicates with a lower portion of a cooling chamber at a lowered position. And a high-speed circulation gas-cooled vacuum heat treatment furnace having an upper suction port communicating with the upper part of the cooling chamber at the ascending position . The upper and lower rectifiers are composed of an equal distribution unit and a rectification unit stacked on each other, or have both functions of an equal distribution unit and a rectification unit,
The uniform distribution section has a plurality of pressure losses arranged uniformly in a direction perpendicular to the ascending gas flow in order to achieve a uniform distribution of flow velocity by providing a flow resistance having a pressure loss coefficient of 0.1 or more of the ascending gas flow. Generating means,
3. The high-speed circulating gas-cooled vacuum heat treatment furnace according to claim 1, wherein the rectification unit includes a plurality of rectification grids that rectify the flow direction of the rising gas flow that has passed through the uniform distribution unit. Furthermore, high-speed circulation gas cooling type vacuum heat treating furnace according to claim 1 or 2 above and below the cooling chamber an auxiliary distribution mechanisms for guiding the direction of gas flow into and out of the flow from the gas direction switching device, it is characterized.

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