Preparation process and preparation device of cubic boron nitride sintered body

Abstract

The invention discloses a cubic boron nitride sintered body preparation process and device, and particularly relates to the technical field of sintered body preparation.The cubic boron nitride sintered body preparation device comprises a hot-pressing sintering furnace body, a hearth is arranged in the hot-pressing sintering furnace body, a lining is fixedly arranged on the inner side of the hearth, and the cubic boron nitride sintered body preparation device further comprises a hot-pressing assembly, a water cooling assembly, an inflation assembly and a drying assembly; the hot pressing assembly comprises two hydraulic columns, the opposite ends of the two hydraulic columns are provided with insulating parts, the opposite ends of the two insulating parts are provided with hot pressing heads, each hot pressing head is internally provided with a copper bus, and the water cooling assembly comprises a circulating water cooler. The spiral exhaust pipe is arranged in the interlayer of the lining and the hearth, the heat dissipation efficiency in the lining is improved, the interiors of the hot-pressing head and the cooling groove are dried through the drying assembly, the efficiency of the hot-pressing head is prevented from being reduced, damage of moisture to the hot-pressing head is reduced, and the service life of the hot-pressing head is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of sintered body preparation, and more specifically, to a cubic boron nitride sintered body preparation process and a preparation device. Background Art

[0002] At present, when sintering cubic boron nitride, a hot pressing sintering furnace is usually used to hot press the cubic boron nitride material. The raw material particles are bonded under high temperature and high pressure conditions to form a dense sintered body. However, the current hot pressing sintering furnace has the following problems when in use:

[0003] When the hot pressing sintering furnace performs hot pressing sintering on cubic boron nitride materials, when cooling is required after sintering is completed, the existing cooling method is to allow water from the water cooling system to flow into the interlayer between the furnace and the lining, thereby taking away the heat inside the lining. Since the cold water cannot contact the inside of the lining, the contact area is limited, and in order to increase the cooling rate, the water flow rate needs to be faster, resulting in insufficient utilization of the cold water in the water cooling system and a slow cooling rate.

[0004] And when cooling the hot-pressed parts, since grooves need to be opened inside the hot-pressed parts, some water will still remain in the grooves after the cold water cools the hot-pressed parts, causing the inside of the hot-pressing head to be moist. This may affect the normal use of the machine for a long time. If it is not used for a long time in winter, the water in the groove may freeze, affecting the service life of the machine and being unfavorable for the maintenance and care of the machine. Summary of the invention

[0005] In order to overcome the above defects of the prior art, an embodiment of the present invention provides a cubic boron nitride sintered body preparation process and preparation device, which solves the problems raised in the above background technology by setting a hot pressing component, a water cooling component, an inflation component and a drying component.

[0006] To achieve the above object, the present invention provides the following technical solution: a process for preparing a cubic boron nitride sintered body, comprising the following steps:

[0007] S1. Mix the cubic boron nitride fine powder and a small amount of additives;

[0008] S2. Pre-press once in an isostatic press at a pressure of 100-150 MPa;

[0009] S3. The pre-pressed material is crushed to less than 0.5 mm to facilitate the subsequent heating and pressurization process, and the crushed material is loaded into a graphite mold;

[0010] S4. The assembled graphite mold is placed in a hot pressing sintering furnace body, heated and pressurized in a hot pressing sintering furnace body, the temperature range is 600-900 degrees Celsius, the pressure is 20-25 MPa, and the temperature is kept for several minutes to 1 hour;

[0011] S5. After sintering is completed, water cooling is performed.

[0012] The present invention also proposes a cubic boron nitride sintered body preparation device, comprising the hot pressing sintering furnace body, wherein a furnace is arranged in the hot pressing sintering furnace body, an inner lining is fixedly arranged on the inner side of the furnace, and one side of the lining has an opening, and further comprising:

[0013] A hot pressing assembly, the hot pressing assembly comprising two hydraulic columns fixedly arranged in the hot pressing sintering furnace body, the two hydraulic columns being opposite to each other up and down, the opposite ends of the two hydraulic columns both passing through the furnace and inserted into the inner lining, the opposite ends of the two hydraulic columns being provided with insulating members, the opposite ends of the two insulating members being provided with hot pressing heads respectively, each of the hot pressing heads being provided with a copper busbar for heating the hot pressing head, the copper busbar being electrically connected to an external power supply;

[0014] A water cooling assembly, the water cooling assembly comprising a circulating water cooler disposed in the hot pressing sintering furnace body, for cooling the interior of the furnace and the hot pressing head;

[0015] A gas filling component, which is arranged on a side of the hot pressing sintering furnace body away from the lining opening and is used to fill the lining with protective gas;

[0016] A drying component is arranged on one side of the furnace and is used to dry the inside of the hot pressing head after water cooling.

[0017] Preferably, the hot pressing assembly further comprises a hydraulic system disposed in the hot pressing sintering furnace body, and both of the two hydraulic columns are connected to the hydraulic system via hydraulic pipes.

[0018] Preferably, the water cooling component also includes two give-way grooves opened on each of the hydraulic columns, two through grooves opened on each of the insulating parts, each of the through grooves is communicated with the corresponding give-way grooves, a cooling groove is opened on the hot pressure head, each of the cooling grooves is communicated with the corresponding two through grooves, two drain pipes are arranged on the circulating water cooler, each of the drain pipes is inserted into the corresponding give-way groove, through groove and cooling groove, one end of the drain pipe inserted into the corresponding cooling groove is communicated with the cooling groove, and two return pipes are arranged on the circulating water cooler, each of the return pipes is inserted into the corresponding give-way groove, through groove and cooling groove, one end of the return pipe inserted into the corresponding cooling groove is communicated with the cooling groove.

[0019] Preferably, the circulating water cooler is provided with a drain pipe, which is inserted into the lower side of the interlayer between the furnace and the lining, and the circulating water cooler is provided with a return pipe which is inserted into the upper side of the interlayer between the furnace and the lining, and both the return pipe and the return liquid pipe are provided with temperature sensors for detecting the temperatures of the return pipe and the return liquid pipe.

[0020] Preferably, the inflation component includes a high-pressure air pump arranged in the hot pressing and sintering furnace body, one end of the high-pressure air pump is inserted into the interior of the liner and communicated with the interior of the liner, the liner is provided with an exhaust pipe with an air inlet end inserted into the liner and communicated with the interior of the liner, the middle part of the exhaust pipe is located between the liner and the furnace, the exhaust end of the exhaust pipe extends out of the furnace and the hot pressing and sintering furnace body, and the exhaust end of the exhaust pipe is provided with a first solenoid valve for controlling the discharge of gas in the liner.

[0021] Preferably, the drying component includes an air storage part fixedly arranged on the side of the furnace away from the first solenoid valve, a heat preservation part is arranged on the outside of the air storage part, the interior of the air storage part is connected with the interior of the lining through a second solenoid valve and a connecting pipe, the second solenoid valve is used to control the discharge of gas in the lining into the air storage part, a moving part is slidingly arranged inside the air storage part, and an elastic part is arranged between the side of the moving part away from the second solenoid valve and the air storage part.

[0022] Preferably, two third solenoid valves are provided on the gas storage component for controlling the discharge of gas in the gas storage component, and each of the third solenoid valves is provided with an outlet pipe at one end away from the gas storage component, and the free end of the outlet pipe is connected to the corresponding liquid discharge pipe.

[0023] Preferably, a vacuum system is provided inside the hot pressing sintering furnace body, and the vacuum system is connected to the interior of the lining for maintaining the interior of the lining in a vacuum state. A control system is provided outside the hot pressing sintering furnace body, and the first solenoid valve, the second solenoid valve, the third solenoid valve, the circulating water cooler, the hydraulic system and the vacuum system are all electrically connected to the control system. The control system controls the connection or disconnection of the copper busbar with an external power supply, and the temperature sensor is electrically connected to the control system.

[0024] Preferably, a sealing member is hinged on the hot pressing sintering furnace body, and the sealing member can cover the openings of the furnace chamber and the lining.

[0025] Technical effects and advantages of the present invention:

[0026] 1. Through the combined operation of sintering and molding, it can ensure that the material is tightly compressed under high pressure, thereby obtaining a higher density and better uniformity of particle distribution, which helps to improve the overall strength and wear resistance of the material, and can better control the microstructure of the material, thereby optimizing its mechanical and physical properties, so that it can still maintain good performance under extreme conditions such as high temperature and high pressure.

[0027] 2. By spirally arranging the exhaust pipe between the liner and the furnace, the contact time and contact area between the high-temperature protective gas and the water flow are increased, thereby achieving full utilization of the cooling water's heat dissipation effect on the inside of the liner, while reducing the influence of the water-cooling component on the poor heat dissipation effect of the liner caused by the thickness of the liner wall. The inside of the liner can be quickly cooled down, which facilitates the rapid removal of the internal sintered body, reduces the steps and time in the production process, thereby improving production efficiency and reducing production costs.

[0028] 3. The drain pipe is inserted into the lower side of the interlayer and connected with the interlayer, and the return pipe is arranged on the upper side of the interlayer and connected with the interlayer, so that water can gradually accumulate from the bottom and then be discharged from the return pipe on the upper side, thereby increasing the contact time between the water flow and the outer wall of the lining and enhancing the heat dissipation effect.

[0029] 4. By setting up the drying component, the high-temperature and high-pressure gas can be stored through the gas storage component, and the heat preservation operation is performed through the heat preservation component. Then, the cooled hot pressing head, cooling trough and copper busbar are dried. The internal drying of the hot pressing head can reduce the damage to the hot pressing head material caused by the humid environment.

[0030] 5. By drying the inside of the hot pressing head, the unstable product quality caused by the moisture of the hot pressing head can be avoided, the uniformity and consistency of the product can be ensured, and the qualified rate of the product can be improved.

[0031] 6. By drying the inside of the hot press head, it can prevent ice from forming inside the hot press head during winter use, which can prevent the equipment from starting work quickly and affect work efficiency. This is beneficial to extending the service life of the equipment. Drying can reduce safety hazards caused by moisture in the equipment, such as fire or electric shock, thereby improving the safety of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0033] Figure 2 It is a schematic diagram of the full-section front view structure of the present invention.

[0034] Figure 3 The schematic diagram of the structure of the present invention without the hot pressing sintering furnace body is shown.

[0035] Figure 4 It is a schematic diagram of the structure after the sealing member in the present invention is opened.

[0036] Figure 5 It is a schematic diagram of the distribution of the furnace, lining and exhaust pipe in the present invention.

[0037] Figure 6 It is a schematic diagram of the full cross-section structure of the hot pressing component in the present invention.

[0038] Figure 7 It is a stepped cross-sectional view of the hot pressing head in the present invention.

[0039] Figure 8 It is a full cross-sectional schematic diagram of the drying component in the present invention.

[0040] The accompanying drawings are marked as follows: 1. hot pressing sintering furnace body; 101. sealing member; 2. furnace chamber; 201. lining; 3. hot pressing assembly; 301. hydraulic column; 302. insulating member; 303. hot pressing head; 304. copper busbar; 305. hydraulic system; 306. hydraulic pipe; 5. water cooling assembly; 501. circulating water cooler; 502. giving way groove; 503. through groove; 504. cooling groove; 505. drain pipe; 506. return pipe; 507, drain pipe; 508, return pipe; 509, temperature sensor; 6, inflation assembly; 601, high-pressure air pump; 602, exhaust pipe; 603, first solenoid valve; 7, drying assembly; 701, air storage component; 702, insulation component; 703, second solenoid valve; 704, connecting pipe; 705, moving component; 706, elastic component; 707, third solenoid valve; 708, outlet pipe; 8, vacuum system; 9, control system. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1

[0043] When traditional cubic boron nitride is prepared into sintered bodies, the steps of pressing and sintering are usually separated. This method is not only not conducive to the smooth progress of the sintering process, but also has a lower density of the sintered body compared with the hot pressing sintering furnace, which is not conducive to the close bonding between the particles and reduces the density of the sintered body.

[0044] In order to effectively perform hot pressing sintering on cubic boron nitride materials and improve the density of the sintered body, this embodiment provides a cubic boron nitride sintered body preparation process, including the following steps:

[0045] S1. Mix the cubic boron nitride fine powder with an appropriate amount of aluminum powder or aluminum nitride powder or other binder, and make the mixture uniform by ball milling to ensure that the components can be evenly distributed during the sintering process, thereby improving the performance of the sintered body;

[0046] S2. Pre-press once in an isostatic press at a pressure of 100-150 MPa;

[0047] S3. The pre-pressed material is crushed to less than 0.5 mm to facilitate the subsequent heating and pressurization process, and the crushed material is loaded into a graphite mold;

[0048] S4. The assembled graphite mold is placed in the hot pressing sintering furnace body 1, and the hot pressing sintering furnace body 1 is heated and pressurized at a temperature range of 600-900 degrees Celsius and a pressure of 20-25 MPa for several minutes to 1 hour. The raw material particles are bonded under high temperature and high pressure conditions to form a dense sintered body;

[0049] S5. After sintering is completed, the water cooling assembly 5 is used to cool the inside of the hot pressing sintering furnace body 1 and the hot pressing head 303 and perform subsequent processing.

[0050] Embodiment 2

[0051] The above process uses a hot pressing sintering furnace to simultaneously perform hot pressing and sintering of cubic boron nitride materials, which has obvious advantages over traditional molding and sintering. However, after the process is completed, when heat needs to be dissipated between the furnace and the lining, when a water cooling system is used for cooling, the existing cooling method is to allow water in the water cooling system to flow into the interlayer between the furnace and the lining, thereby taking away the heat inside the lining. Since the cold water cannot contact the inside of the lining and the contact area is limited, in order to increase the cooling rate, the water flow rate needs to be faster, resulting in insufficient utilization of the cold water of the water cooling system and a slow cooling rate.

[0052] In order to further improve the superiority of the cubic boron nitride sintered body preparation process of the present invention, this embodiment provides a cubic boron nitride sintered body preparation device, as shown in the accompanying drawings of the specification Figures 1 to 7It can be obtained that the adopted technical scheme includes a hot pressing sintering furnace body 1, a furnace 2 is arranged in the hot pressing sintering furnace body 1, a liner 201 is fixedly arranged on the inner side of the furnace 2, one side of the liner 201 has an opening, and an interlayer is arranged between the liner 201 and the furnace 2 for cooling the liner 201 with cooling water, and also includes a hot pressing component 3, a water cooling component 5 and an inflation component 6, the hot pressing component 3 includes two hydraulic columns 301 fixedly arranged in the hot pressing sintering furnace body 1, the two hydraulic columns 301 are opposite to each other up and down, the opposite ends of the two hydraulic columns 301 are both through the furnace 2 and inserted into the liner 201, the opposite ends of the two hydraulic columns 301 are both provided with insulating parts 302, the opposite ends of the two insulating parts 302 are respectively provided with hot pressing heads 303, and each hot pressing head 303 is provided with A copper busbar 304 is arranged to heat the hot pressing head 303, and the copper busbar 304 is electrically connected to an external power supply. The water cooling component 5 includes a circulating water cooler 501 arranged in the hot pressing sintering furnace body 1, which is used to cool the inside of the furnace 2 and the hot pressing head 303. The charging component 6 is arranged on a side of the hot pressing sintering furnace body 1 away from the opening of the liner 201, and is used to charge the protective gas into the liner 201. The hot pressing component 3 also includes a hydraulic system 305 arranged in the hot pressing sintering furnace body 1, and the two hydraulic columns 301 are connected to the hydraulic system 305 through a hydraulic pipe 306. The water cooling component 5 also includes two make-way grooves 502 provided on each hydraulic column 301, and each insulating member 302 is provided with two through grooves 503, each through groove The slots 503 are all connected to the corresponding give-way slots 502, a cooling slot 504 is provided on the hot pressing head 303, each cooling slot 504 is connected to the two corresponding through slots 503, two drain pipes 505 are provided on the circulating water cooler 501, each drain pipe 505 is inserted into the corresponding give-way slot 502, through slot 503 and cooling slot 504, one end of the drain pipe 505 inserted into the corresponding cooling slot 504 is connected to the cooling slot 504, two return pipes 506 are provided on the circulating water cooler 501, each return pipe 506 is inserted into the corresponding give-way slot 502, through slot 503 and cooling slot 504, one end of the return pipe 506 inserted into the corresponding cooling slot 504 is connected to the cooling slot 504, the circulating water cooler 5 01 is provided with a drain pipe 507, which is inserted into the lower side of the interlayer between the furnace 2 and the liner 201. The circulating water cooler 501 is provided with a return pipe 508 which is inserted into the upper side of the interlayer between the furnace 2 and the liner 201. The return pipe 508 and the return liquid pipe 506 are both provided with temperature sensors 509 for detecting the temperatures of the return pipe 508 and the return liquid pipe 506. The inflation component 6 includes a high-pressure air pump 601 arranged in the hot pressing sintering furnace body 1, one end of the high-pressure air pump 601 is inserted into the interior of the liner 201 and communicated with the interior of the liner 201, and the liner 201 is provided with an exhaust pipe 602 with an air inlet end inserted into the liner 201 and communicated with the interior of the liner 201, and the middle part of the exhaust pipe 602 is located between the liner 201 and the furnace 2.The exhaust end of the exhaust pipe 602 extends out of the furnace 2 and the hot pressing sintering furnace body 1. The exhaust end of the exhaust pipe 602 is provided with a first solenoid valve 603 for controlling the discharge of gas in the lining 201. The hot pressing sintering furnace body 1 is provided with a vacuum system 8, which is connected to the inside of the lining 201 and is used to keep the inside of the lining 201 in a vacuum state. A control system 9 is provided on the outside of the hot pressing sintering furnace body 1. The first solenoid valve 603, the second solenoid valve 703, the third solenoid valve 707, the circulating water cooler 501, the hydraulic system 305 and the vacuum system 8 are all electrically connected to the control system 9. The control system 9 controls the connection or disconnection of the copper busbar 304 with the external power supply. The temperature sensor 509 is electrically connected to the control system 9. A seal 101 is hinged on the hot pressing sintering furnace body 1, and the seal 101 can cover the openings of the furnace 2 and the lining 201.

[0053] When in use, first place the assembled graphite mold on a position where the upper end of the lower hot pressing head 303 can be squeezed and fixed by the upper hot pressing head 303, and the control system 9 starts the hydraulic system 305, so that the hydraulic system 305 controls the extension of the upper hydraulic column 301 to press and fix the assembled graphite mold. The sealing method between the hydraulic column 301 and the liner 201 and the furnace 2 can use the existing sealing method to ensure the sealing performance. After the fixing is completed, the hydraulic system 305 is closed, and then the seal 101 is closed. The locking of the seal 101, the hydraulic system 305 and the hydraulic column 301 are all existing technologies and will not be described in detail here.

[0054] Then, the control system 9 controls the copper busbar 304 to be energized, so that the hot pressing head 303 heats the assembled graphite mold and cubic boron nitride material. The connection method between the copper busbar 304 and the external power supply is the existing technology and will not be described in detail here. At the same time, the hydraulic system 305 transports hydraulic oil to the hydraulic column 301 through the hydraulic pipe 306, so that the upper hydraulic column 301 squeezes the graphite mold downward, and the lower hydraulic column 301 only provides sufficient pressure without stretching, and continuously heats and pressurizes the cubic boron nitride material, so that the two steps of molding and sintering are carried out simultaneously.

[0055] At the same time, the control system 9 controls the high-pressure air pump 601 to fill the inner lining 201 with protective gas, ensuring that the gas inside the inner lining 201 is in a high-pressure state, providing a reliable atmosphere and pressure environment for the hot pressing sintering of cubic boron nitride materials, and effectively increasing the density and other physical properties of the sintered body of cubic boron nitride materials.

[0056] After a period of time, when the forming and sintering of the cubic boron nitride material is completed, the control system 9 controls the copper busbar 304 to disconnect from the external power supply, so that the hydraulic system 305 controls the upper hydraulic column 301 to contract, and no longer extrude the graphite mold, and then starts to water-cool the liner 201 and the hot pressing head 303. The control system 9 controls the circulating water cooler 501 to inject water into the cooling tank 504 of the hot pressing head 303 through the drain pipe 505. This technology is a prior art and will not be described in detail here.

[0057] After passing through the cooling trough 504, the water flows into the circulating water cooler 501 through the return pipe 506 for cooling and then recycling. The circulating water cooler 501 and its working method are both existing technologies and are not described in detail here. At the same time, the control system 9 controls the circulating water cooler 501 to drain water into the interlayer between the lining 201 and the furnace 2 through the drain pipe 507, so that the water flows in contact with the lining 201 and takes away the heat inside the lining 201. The water in the interlayer is discharged into the circulating water cooler 501 through the return pipe 508 for cooling and then recycling, thereby improving the cooling efficiency.

[0058] At the same time, the control system 9 controls the first solenoid valve 603 to open. This technology is prior art and will not be described in detail here. The gas passes through the exhaust pipe 602 in the water flow between the liner 201 and the furnace 2, so that the high-temperature gas contacts the water flow through the exhaust pipe 602, thereby increasing the contact time and contact area between the high-temperature protective gas inside the liner 201 and the water flow, allowing the hot gas to directly contact the water flow, reducing the poor heat dissipation efficiency caused by the wall thickness of the liner 201, improving the heat dissipation efficiency inside the liner 201, and making full use of the heat dissipation effect of the cooling water.

[0059] At the same time, a sealed connection method is adopted between the lining 201 and the furnace 2 to ensure the air tightness between the furnace 2 and the lining 201 and to ensure that water does not leak out. This sealed connection method is a prior art and will not be described in detail here. The gas is discharged through the outlet end of the exhaust pipe 602. A gas collection device can be set outside to collect the gas, which is convenient for recycling or other uses of the protective gas.

[0060] The temperature of the water flow inside the return pipe 508 and the return liquid pipe 506 is detected by the temperature sensor 509. After it is reduced to the specified corresponding temperature, the control system 9 controls the circulating water cooler 501 to stop supplying cooling water, and the water flow no longer participates in the cooling work of the liner 201 and the hot press head 303.

[0061] By combining sintering and molding, the material can be tightly compressed under high pressure, thereby obtaining a higher density and better uniformity of particle distribution, which helps to improve the overall strength and wear resistance of the material, and can better control the microstructure of the material, thereby optimizing its mechanical and physical properties, so that it can still maintain good performance under extreme conditions such as high temperature and high pressure. At the same time, by spirally arranging the exhaust pipe 602 between the liner 201 and the furnace 2, the contact time and contact area of ​​the high-temperature protective gas and the water flow are increased, thereby achieving full utilization of the cooling water to the heat dissipation effect of the inner liner 201. The effect is achieved while reducing the influence of the water cooling assembly 5 on the poor heat dissipation effect inside the liner 201 caused by the wall thickness of the liner 201, and the interior of the liner 201 can be quickly cooled down, which is convenient for quickly removing the internal sintered body, reducing the steps and time in the production process, thereby improving production efficiency and reducing production costs. The drain pipe 507 is inserted into the lower side of the interlayer and connected to the interlayer, and the return pipe 508 is arranged on the upper side of the interlayer and connected to the interlayer, which can make water gradually accumulate from the bottom and then be discharged from the return pipe 508 on the upper side, thereby increasing the contact time between the water flow and the outer wall of the liner 201 and enhancing the heat dissipation effect.

[0062] Embodiment 3

[0063] When cooling the hot-pressed parts, since grooves need to be opened inside the hot-pressed parts, some water will still remain in the grooves after the cold water cools the hot-pressed parts, causing the inside of the hot-pressing head to be moist. This may affect the normal use of the machine for a long time. If the machine is not used for a long time in winter, the water in the groove may freeze, affecting the service life of the machine and being unfavorable for the maintenance of the machine.

[0064] In order to solve the above technical problems, based on the above embodiments, Figures 1 to 8 It can be seen that the adopted technical solution includes a drying component 7, which is arranged on one side of the furnace 2 and is used to dry the inside of the hot pressing head 303 after water cooling. The drying component 7 includes an air storage component 701 fixedly arranged on the furnace 2 away from the side of the first electromagnetic valve 603, and an insulation component 702 is arranged on the outside of the air storage component 701. The inside of the air storage component 701 is connected with the inside of the liner 201 through the second electromagnetic valve 703 and the connecting pipe 704. The second electromagnetic valve 703 is used to control the gas in the liner 201. The gas is discharged into an air storage member 701, a movable member 705 is slidably arranged inside the air storage member 701, an elastic member 706 is arranged between the side of the movable member 705 away from the second solenoid valve 703 and the air storage member 701, two third solenoid valves 707 are arranged on the air storage member 701, and are used to control the discharge of gas in the air storage member 701, and an air outlet pipe 708 is arranged at one end of each of the third solenoid valves 707 away from the air storage member 701, and the free end of the air outlet pipe 708 is connected to the corresponding discharge pipe 505.

[0065] During specific use, after the hot pressing and sintering of the cubic boron nitride material is completed, since the gas in the lining 201 is a high-temperature and high-pressure protective gas, the control system 9 is used to control the second solenoid valve 703 to open, so that the high-temperature and high-pressure gas inside the lining 201 is introduced into a part of the interior of the gas storage component 701 through the connecting pipe 704 and the second solenoid valve 703, so that the gas storage component 701 stores the high-temperature and high-pressure gas of this part, and a heat preservation component 702 is arranged on the outside, which can ensure that the heat loss of this part of the gas is less to a certain extent. Under the action of air pressure, the moving component 705 pushes the elastic component 706 to contract. After a certain period of time, the control system 9 controls the second solenoid valve 703 to close to prevent the gas inside the gas storage component 701 from flowing back when the interior of the lining 201 is subsequently cooled. This operation is performed before the water cooling operation and does not conflict with the water cooling operation.

[0066] Then, a water cooling operation is performed. The specific water cooling process is as described in the above-mentioned embodiment 2. After the cooling of the hot pressure head 303 is completed, the water supply is stopped after the temperature reaches the corresponding standard detected by the temperature sensor 509, and then the control system 9 controls the third solenoid valve 707 to open, and the elastic member 706 pushes the high-temperature gas inside the gas storage member 701 to be discharged into the drain pipe 505, and the water in the drain pipe 505 is discharged into the circulating water cooler 501 through the return pipe 506. At the same time, after the water is discharged, the high-temperature and high-pressure gas inside the gas storage member 701 begins to dry the drain pipe 505 and the cooling tank 504, so that the residual water flow inside evaporates under the action of high temperature, and is discharged into the circulating water cooler 501 through the return pipe 506. The protective gas can be discharged from the circulating water cooler 501 through the existing technology.

[0067] By setting up the drying component 7, the high-temperature and high-pressure gas can be stored through the gas storage component 701, and the insulation operation can be performed through the insulation component 702. Then, the cooled hot pressing head 303, the cooling trough 504 and the copper busbar 304 are dried. The internal drying of the hot pressing head 303 can reduce the damage to the material of the hot pressing head 303 caused by the humid environment. By drying the inside of the hot pressing head 303, the unstable quality of the product caused by the moisture of the hot pressing head 303 can be avoided, the uniformity and consistency of the product can be ensured, the qualified rate of the product can be improved, and the internal freezing of the hot pressing head 303 can be prevented when it is used in winter, resulting in the inability to start work quickly and affecting work efficiency. It is beneficial to extend the service life of the equipment. Drying can reduce the safety hazards caused by moisture in the equipment, such as fire or electric shock, thereby improving the safety of the production process.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A process for preparing a cubic boron nitride sintered body, characterized in that: The following steps are involved: S1. Mix the cubic boron nitride fine powder and a small amount of additives; S2. Pre-press once in an isostatic press at a pressure of 100-150 MPa; S3. Crushing: crush the pre-pressed material to less than 0.5 mm, and load the crushed material into a graphite mold; S4. The assembled graphite mold is placed in a hot pressing sintering furnace body (1), and a sintered body is prepared by heating and pressurizing the hot pressing sintering furnace body (1); S5. After sintering is completed, water cooling is performed.

2. A cubic boron nitride sintered body preparation device, used for a cubic boron nitride sintered body preparation process as claimed in claim 1, characterized in that: The hot pressing sintering furnace body (1) is provided with a furnace (2) in the hot pressing sintering furnace body (1), an inner lining (201) is fixedly provided on the inner side of the furnace (2), and one side of the inner lining (201) has an opening, and further comprises: A hot pressing assembly (3), the hot pressing assembly (3) comprising two hydraulic columns (301) fixedly arranged in the hot pressing sintering furnace body (1), the two hydraulic columns (301) being opposed to each other up and down, the opposite ends of the two hydraulic columns (301) both passing through the furnace (2) and inserted into the lining (201), the opposite ends of the two hydraulic columns (301) both being provided with insulating members (302), the opposite ends of the two insulating members (302) both being provided with hot pressing heads (303), each of the hot pressing heads (303) being provided with a copper busbar (304) for heating the hot pressing head (303), the copper busbar (304) being electrically connected to an external power supply; A water cooling component (5), the water cooling component (5) comprising a circulating water cooler (501) arranged in the hot pressing sintering furnace body (1) and used for cooling the interior of the furnace (2) and the hot pressing head (303); A charging component (6), the charging component (6) being arranged in the hot pressing sintering furnace body (1) at a side away from the opening of the lining (201), and being used for charging protective gas into the lining (201); A drying component (7), the drying component (7) is arranged on one side of the furnace (2) and is used to dry the inside of the hot pressing head (303) after water cooling.

3. The device for preparing a cubic boron nitride sintered body according to claim 2, characterized in that: The hot pressing assembly (3) further comprises a hydraulic system (305) arranged in the hot pressing sintering furnace body (1), and the two hydraulic columns (301) are connected to the hydraulic system (305) via hydraulic pipes (306).

4. The device for preparing a cubic boron nitride sintered body according to claim 3, characterized in that: The water cooling assembly (5) further comprises two clearance grooves (502) provided on each of the hydraulic columns (301), two through grooves (503) provided on each of the insulating members (302), each of the through grooves (503) being connected to the corresponding clearance grooves (502), a cooling groove (504) provided on the hot pressing head (303), each of the cooling grooves (504) being connected to the corresponding two through grooves (503), and two drainage pipes (505) provided on the circulating water cooler (501), each of the drainage pipes (505) being inserted into the The circulating water cooler (501) is provided with two liquid return pipes (506), each of which is inserted into the corresponding giving way groove (502), the through groove (503) and the cooling groove (504), and one end of the liquid return pipe (506) is inserted into the corresponding cooling groove (504) and is communicated with the cooling groove (504).

5. The device for preparing a cubic boron nitride sintered body according to claim 4, characterized in that: The circulating water cooler (501) is provided with a drain pipe (507), and the drain pipe (507) is inserted into the lower side of the interlayer between the furnace (2) and the inner lining (201). The circulating water cooler (501) is provided with a return pipe (508) inserted into the upper side of the interlayer between the furnace (2) and the inner lining (201). The return pipe (508) and the liquid return pipe (506) are both provided with temperature sensors (509) for detecting the temperatures of the return pipe (508) and the liquid return pipe (506).

6. The device for preparing a cubic boron nitride sintered body according to claim 2, characterized in that: The inflation component (6) comprises a high-pressure air pump (601) arranged in the hot pressing sintering furnace body (1), one end of the high-pressure air pump (601) is inserted into the interior of the liner (201) and communicated with the interior of the liner (201), the liner (201) is provided with an exhaust pipe (602) with an air inlet end inserted into the liner (201) and communicated with the interior of the liner (201), the middle part of the exhaust pipe (602) is located between the liner (201) and the furnace (2), the exhaust end of the exhaust pipe (602) extends out of the furnace (2) and the hot pressing sintering furnace body (1), and the exhaust end of the exhaust pipe (602) is provided with a first solenoid valve (603) for controlling the discharge of gas in the liner (201).

7. The device for preparing a cubic boron nitride sintered body according to claim 6, characterized in that: The drying component (7) comprises an air storage component (701) fixedly arranged on a side of the furnace (2) away from the first solenoid valve (603), a heat-insulating component (702) being arranged on the outside of the air storage component (701), the interior of the air storage component (701) being connected to the interior of the liner (201) via a second solenoid valve (703) and a connecting pipe (704), the second solenoid valve (703) being used to control the discharge of gas in the liner (201) into the air storage component (701), a moving component (705) being slidably arranged inside the air storage component (701), an elastic component (706) being arranged between the side of the moving component (705) away from the second solenoid valve (703) and the air storage component (701).

8. The device for preparing a cubic boron nitride sintered body according to claim 7, characterized in that: The gas storage member (701) is provided with two third solenoid valves (707) for controlling the discharge of gas in the gas storage member (701); each of the third solenoid valves (707) is provided with an air outlet pipe (708) at one end away from the gas storage member (701); the free end of the air outlet pipe (708) is connected to the corresponding liquid discharge pipe (505).

9. The device for preparing a cubic boron nitride sintered body according to claim 8, characterized in that: A vacuum system (8) is arranged inside the hot pressing sintering furnace body (1), and the vacuum system (8) is connected to the inside of the lining (201) and is used to keep the inside of the lining (201) in a vacuum state. A control system (9) is arranged outside the hot pressing sintering furnace body (1), and the first solenoid valve (603), the second solenoid valve (703), the third solenoid valve (707), the circulating water cooler (501), the hydraulic system (305) and the vacuum system (8) are all electrically connected to the control system (9). The control system (9) controls the connection or disconnection of the copper busbar (304) with an external power supply, and the temperature sensor (509) is electrically connected to the control system (9).

10. The device for preparing a cubic boron nitride sintered body according to claim 2, characterized in that: A sealing member (101) is hinged on the hot pressing sintering furnace body (1), and the sealing member (101) can cover the openings of the furnace chamber (2) and the lining (201).

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