CN107899513B - Concave-convex hexahedral top ultrahigh pressure sealing assembly and diamond synthesis process - Google Patents
Concave-convex hexahedral top ultrahigh pressure sealing assembly and diamond synthesis process Download PDFInfo
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- CN107899513B CN107899513B CN201810010344.9A CN201810010344A CN107899513B CN 107899513 B CN107899513 B CN 107899513B CN 201810010344 A CN201810010344 A CN 201810010344A CN 107899513 B CN107899513 B CN 107899513B
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- 238000007789 sealing Methods 0.000 title claims abstract description 69
- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 30
- 239000010432 diamond Substances 0.000 title claims abstract description 30
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 23
- 238000003786 synthesis reaction Methods 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000008569 process Effects 0.000 title claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 9
- 238000003860 storage Methods 0.000 claims description 9
- 230000008859 change Effects 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 3
- 238000005299 abrasion Methods 0.000 abstract description 7
- 238000013461 design Methods 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 239000003921 oil Substances 0.000 description 33
- 239000010720 hydraulic oil Substances 0.000 description 11
- 229910052903 pyrophyllite Inorganic materials 0.000 description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 10
- 229910002804 graphite Inorganic materials 0.000 description 9
- 239000010439 graphite Substances 0.000 description 9
- 238000010791 quenching Methods 0.000 description 6
- 230000000171 quenching effect Effects 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000005496 tempering Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 2
- 238000005087 graphitization Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000035764 nutrition Effects 0.000 description 2
- 235000016709 nutrition Nutrition 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
- B01J3/06—Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1438—Cylinder to end cap assemblies
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1447—Pistons; Piston to piston rod assemblies
- F15B15/1452—Piston sealings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
Abstract
The invention belongs to the technical field of ultra-high pressure ultra-hard material equipment, and relates to a concave-convex six-sided top ultra-high pressure sealing component and a diamond synthesis process, wherein the concave-convex six-sided top ultra-high sealing component comprises a concave bottom piston, an inner convex working cylinder, a cylinder cover and a rear plug; the inner bottom of the inner convex working cylinder is provided with a circular truncated cone-shaped bulge, the center of the circular truncated cone-shaped bulge is communicated to form an oil inlet hole, the concave bottom piston is arranged inside the inner convex working cylinder in a matched mode, the cylinder cover is connected to the inner convex working cylinder through a bolt, and the rear plug is connected to the center of the outer bottom surface of the inner convex working cylinder through a bolt. The ultra-high pressure sealing component is used in the hexahedral top press for diamond synthesis, wherein the concave structural design of the concave bottom piston reduces the weight of the piston, reduces the abrasion of sealing elements, is beneficial to the enlargement of high-pressure equipment, and enables the diamond to be contained.
Description
Technical Field
The invention belongs to the technical field of ultra-high pressure ultra-hard material equipment, and relates to a concave-convex six-sided top ultra-high pressure sealing component and a diamond synthesis process.
Background
The hexahedral top ultrahigh pressure equipment is mainly used for ultrahigh pressure synthesis of superhard materials such as diamond, cubic boron nitride, B4C and the like, and gradually increases in size along with the requirement of large-scale products, the dead weight of a piston of a high-pressure cylinder with continuously increased volume increases, so that the piston is difficult to manufacture, assemble and adjust a press, three O-shaped sealing rings of the piston are extremely easy to wear and lose efficacy due to long-time dry friction, the sealing effect is influenced, and the surface of the piston between the O-shaped sealing rings and the working cylinder are easy to generate dry friction, so that the working cylinder and the piston lose efficacy; meanwhile, the working cylinder can bear larger pressure, and if the back plugging hole of the oil cylinder is larger, the service life of the back plugging bearing the larger pressure is seriously influenced; the bottom of the working cylinder is usually in a step shaft-shaped structure to realize mechanical occlusion between the rear plug and the working cylinder, and a sealing ring is additionally arranged to realize sealing between the oil inlet pipe and the working cylinder.
The problem of tight combination of a working cylinder and a piston, a cylinder cover and a rear plug after the six-sided press is enlarged, the problem of friction and abrasion between the piston and the cylinder and the problem of leakage of high-pressure oil of the rear plug result in that the system pressure (< 120 MPa) of the ultra-high pressure equipment cannot break through the pressure threshold of the high-pressure equipment of 100MPa proposed by Bridgman, and further development of the six-sided ultra-high pressure equipment is limited.
The domestic diamond is synthesized by adopting a domestic hexahedral top equipment static pressure catalyst method, wherein graphite is used as a raw material, transition metal or alloy is used as a catalyst, a hydraulic press is used for generating constant high pressure, direct current or alternating current is used for generating continuous high temperature, so that the graphite is converted into diamond, and the conversion condition is generally 5-7GPa and 1300-1700 ℃; in the synthesis process of diamond, maintaining constant synthesis pressure and synthesis temperature are key to changing graphite carbon atoms into diamond, however, the synthesis time of diamond is longer, and any leakage problem of ultra-high pressure oil can seriously affect the yield and the crystal form regularity of diamond.
Disclosure of Invention
The invention aims to solve the technical problems of short service life and high-pressure oil leakage of the existing sealing assembly and design a concave-convex hexahedral top ultrahigh-pressure sealing assembly.
The invention adopts the technical proposal for solving the technical problems that:
a concave-convex six-surface top ultrahigh pressure sealing assembly comprises a concave bottom piston, an inner convex working cylinder, a cylinder cover and a rear plug; the cylinder cover is connected to the inner convex working cylinder through bolts, two sealing rings are overlapped between the cylinder cover and the inner convex working cylinder, and the rear plug is connected to the center of the bottom surface outside the inner convex working cylinder through bolts.
Further, the sealing structure is three O-shaped sealing rings which are attached to the side wall of the concave bottom piston in a surrounding mode, a sealing groove is formed between each O-shaped sealing ring and the inner wall of the inner convex working cylinder, a radial annular oil storage groove is formed in the space between every two adjacent O-shaped sealing rings, and a reset rod is arranged between every two adjacent O-shaped sealing rings in a plugging mode.
Furthermore, the reset rod is arranged in the oil storage tank around the circumference in a clearance mode, the reset rod is coated by rubber materials, the reset spring is further wrapped to form a closed structure, and the outer side of the coating of the reset rod is provided with fold skin.
Furthermore, the whole cylinder cover is in a ladder shape, the cylinder cover is contacted with the inner protruding working cylinder by the inner diameter dimension of three O-shaped sealing rings, and a piston built-in axial guide key slot is arranged on the inner diameter of the cylinder cover close to the front cavity of the inner protruding working cylinder, and an anti-rotation key is inserted in the corresponding axial guide key slot.
Further, the oil inlet hole at the center of the inner protruding working cylinder is of a small-aperture structure, one port of the oil inlet hole is located at the center of the upper end face of the circular truncated cone-shaped protrusion, the other port of the oil inlet hole is located at the center of the bottom end face of the inner protruding working cylinder, the oil inlet hole is communicated with the rear plug in a sealing contact manner, and four fixing bolt holes are formed in the periphery of the oil inlet hole of the bottom end face of the outer side of the inner protruding working cylinder and used for fixing the rear plug through bolts.
The diamond synthesis process utilizes the concave-convex hexahedral top ultrahigh pressure sealing component, and the process is carried out according to the following steps: placing the synthetic block into a high-pressure cavity of a hexahedral top press, pressurizing to 4-6MPa, communicating with an overpressure to 65-75MPa, maintaining the pressure for 4-7.6 minutes, pressurizing to 80-88MPa for 15-45s, heating the synthetic block when the pressure reaches 40-48MPa in the pressure change process, and heating the synthetic block to 1340-1440 ℃ for 10-15s and preserving heat; maintaining the pressure for 1.5-3min, and reducing the temperature from 1340-1440 ℃ to 1200-1300 ℃; the temperature is kept unchanged at 1200-1300 ℃, the pressure is continuously increased at the speed of 0.02-0.04MPa/s, the pressure is maintained and reduced when the pressure is increased to 89-98MPa, the pressure is reduced after the temperature is reduced to the room temperature, the pressure is relieved, and the synthesis is completed after the pressure is relieved to normal pressure.
Compared with the prior art, the invention has the following beneficial effects:
1. the concave structure design of the concave bottom piston reduces the weight of the piston under the condition of not reducing the strength and rigidity of the concave bottom piston, reduces the abrasion of a sealing element, and is beneficial to the installation and maintenance of equipment and the enlargement of high-voltage equipment; the three O-shaped sealing devices and the two oil storage tanks greatly increase the sealing performance of high-pressure oil, reduce the friction and abrasion between the piston and the oil cylinder, store part of hydraulic oil before installation of the two oil storage tanks, ensure the lubricating effect by overflowing the hydraulic oil when the piston moves, greatly reduce the abrasion between the piston and the cylinder body and ensure the tightness of the hydraulic system.
2. The round table bulge structure of the inner bulge type working cylinder increases the thickness of the cylinder bottom, further improves the bearing capacity of the working cylinder bottom, improves the stress state of the working cylinder bottom, avoids the cracking phenomenon of the working cylinder, and greatly improves the bearable pressure limit of the working cylinder; the thicker raised cylinder bottom structure greatly reduces the internal stress around the central oil inlet hole of the cylinder bottom, can be matched with the design of the oil inlet hole with smaller diameter, reduces the stress of the rear plug and prolongs the service life of the rear plug; meanwhile, four bolt holes are added at the bottom of the working cylinder, and the working cylinder is tightly combined with the rear plug by matching with the conical connection at the bottom of the oil inlet pipe, so that leakage of high-pressure oil seal is avoided.
3. The sealing performance of the press is greatly improved by the structural design of the O-shaped sealing ring in the cavity of the working cylinder, the leakage problem of the front cavity is effectively solved, the system pressure (< 120 MPa) of the ultrahigh pressure equipment can be improved, and the pressure threshold of the high pressure equipment of 100MPa proposed by Bridgman is broken through.
4. The built-in guide key and the key groove limit the rotation of the piston, ensure the centering of the ultrahigh pressure equipment, simultaneously reduce the abrasion failure phenomenon of the sealing ring and the piston caused by the entering of pyrophyllite dust into the oil cylinder, improve the working environment of the cylinder cover and prolong the working life of the piston and the cylinder cover.
5. The hexahedral top press utilizing the device can exert the performance of the hexahedral top press in the diamond synthesis process, so that the raw material is converted into diamond under the action of ultrahigh pressure, the quality and the quality of the diamond are ensured, and the device has popularization.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the present invention.
FIG. 2 is an enlarged schematic view of the C-site of the present invention.
Fig. 3 is a schematic structural view of the reset lever in the present invention.
Fig. 4 is an enlarged schematic view of the D site of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples, but embodiments of the present invention are not limited thereto.
Example 1
As shown in fig. 1, a concave-convex hexahedral top ultrahigh pressure sealing assembly comprises a concave bottom piston 1, an inner convex working cylinder 8, a cylinder cover 2 and a rear plug 10; the inside bottom of interior bellied working cylinder 8 has a round platform shape arch, concave bottom piston 1 sets up in the interior bellied working cylinder 8 is inside to be provided with seal structure on its outer wall that is close to the concave bottom, cylinder cap 2 passes through bolted connection on interior bellied working cylinder 8, and the stack sets up the twice sealing washer between the two, back stifled 10 passes through bolted connection in the center department of the outside bottom surface of interior bellied working cylinder 8.
The heat treatment process of the concave bottom piston 1 is quenching and tempering, namely double-liquid quenching and high-temperature tempering treatment, and the specific treatment process is as follows: preheating to 640 ℃, preserving heat for a certain time, then heating to 800 ℃, preserving heat for 3 hours, and finally performing double-liquid quenching, namely oil quenching and water quenching treatment, tempering at a high temperature of 640 ℃ after quenching, preserving heat for 15 hours, and air cooling to room temperature; the heat treatment process ensures the rigidity of the concave bottom piston 1 and ensures the effective transmission of cavity pressure.
Specifically, the sealing structure arranged on the side wall of the concave bottom piston 1 close to the concave bottom is three O-shaped sealing rings which are circumferentially attached to the side wall of the concave bottom piston, the O-shaped sealing rings 3 and the inner wall of the inner convex working cylinder 8 form sealing grooves 4, a radial annular groove is formed in the space between every two adjacent O-shaped sealing rings 3, the radial annular groove is an oil storage groove 5, reset rods 11 are plugged in between the inner sides of the two adjacent O-shaped sealing rings, and the number of the reset rods is four, and are arranged in the oil storage groove 5 around the circumference in a clearance mode, as shown in fig. 2, the reset rods 11 are used for resetting when the O-shaped sealing rings 3 are pressed by hydraulic oil, so that the sealing effect is prevented from being lost; the reset rod 11 is a closed structure with a reset spring 12 inside, the reset rod 11 is coated by rubber materials so as to wrap the reset spring 12 to form a closed structure, and the outer side of the coating of the reset rod 11 is provided with a fold skin 13, so that the spring 12 is convenient to deform to change in length, as shown in fig. 3.
Specifically, as shown in fig. 1, the cylinder cover 2 is in a step shape, the cylinder cover 2 is in contact with the inner diameter of the inner protruding working cylinder 8 by three O-shaped sealing rings, a piston built-in axial guiding key slot 6 is arranged on the inner diameter of the cylinder cover 2 near the front cavity of the inner protruding working cylinder 8, and an anti-rotation key 7 is inserted in the corresponding axial guiding key slot 6 so as to prevent the piston from rotating and influence the sealing effect.
Specifically, the oil inlet 9 in the center of the inner protruding working cylinder 8 is in a small-aperture structure, the oil inlet 9 is communicated with a circular truncated cone-shaped protrusion in the inner protruding working cylinder 8, namely, one port of the oil inlet 9 is located in the center of the upper end face of the circular truncated cone-shaped protrusion, the other port of the oil inlet 9 is located in the center of the outer end face of the bottom of the inner protruding working cylinder 8, the oil inlet 9 is in contact communication with the rear plug 10 through a conical seal 14, and four fixing bolt holes are formed around the oil inlet 9 in the outer bottom end face of the inner protruding working cylinder 8 and used for fixing the rear plug 10 through bolts, as shown in fig. 4.
When the hydraulic oil leakage preventing device is used, hydraulic oil enters the oil inlet hole 9 through the rear plug 10, and the oil inlet hole 9 is in conical sealing connection with the rear plug 10, so that leakage of the hydraulic oil is effectively prevented; hydraulic oil enters the inner convex working cylinder 8, the hydraulic oil pushes the concave bottom piston 1 to move, and when the sealing groove 4 at the rear end of the concave bottom piston 1 is closed, the hydraulic oil can be prevented from leaking; when the O-shaped sealing ring 3 is driven to slide due to the movement of the concave bottom piston 1, the O-shaped sealing rings mutually extrude to extrude hydraulic oil in the oil storage tank 5 so as to reduce friction and abrasion between the concave bottom piston and the inner surface of the inner convex working cylinder 8, meanwhile, the reset rod 11 is stressed to extrude the reset spring 12 to compress, and when the O-shaped sealing ring 3 slides to the rear end, the reset spring 12 resets to jack up the O-shaped sealing ring 3, so that dislocation losing tightness is prevented when the O-shaped sealing ring slides again; the middle part of the concave bottom piston 1 is provided with an axial guiding key groove 6 and an anti-rotation key 7, so that the piston is prevented from rotating, the sealing effect is prevented from being influenced, and as the three O-shaped sealing rings 3 are arranged on the outer diameter of the rear end of the concave bottom piston 1, and the two sealing rings are overlapped between the outer diameter of the cylinder cover 2 and the inner convex working cylinder 8, the inner and outer sealing of the device is perfect, and hydraulic oil in the front cavity of the working cylinder can be effectively prevented from being leaked.
Example 2
The concave-convex hexahedral top ultrahigh pressure sealing assembly in the above embodiment 1 is applied to a hexahedral top press, and the formed high pressure hexahedral top press can be used for the synthesis of diamond, and the process is as follows: putting the pyrophyllite synthetic block into a high-pressure cavity of the hexahedral press, pushing six pistons of the hexahedral press under the action of a supercharger, and performing idle stroke; enabling six hard alloy top hammers of the hexahedral top press to be in contact with pyrophyllite, filling liquid and pressurizing, communicating the overpressure to 65MPa by using the hexahedral top press to reach the pressure of 4MPa, keeping the pressure for 5min at the overpressure speed of about 0.7MPa/s, and pressurizing 15s to the synthesis pressure of 80MPa, so that graphite columns (graphite powder and metal catalyst powder) in a synthesis cavity of the pyrophyllite synthesis block are fully melted, and graphite is fully converted; heating is started when the pressure is 40MPa in the pressurizing process from normal pressure to 65MPa, so that the situation that pyrophyllite cannot be sealed under the conditions of low pressure and high temperature to burn out is avoided, the temperature is increased to 1340 ℃ for 10 seconds, and heat is preserved, so that graphite and metal powder are mutually dissolved and mutually infiltrated; maintaining the pressure at 65MPa for 3 minutes, and reducing the temperature from 1350 ℃ to 1200 ℃ for a certain temperature to prevent diamond graphitization caused by overhigh temperature; the temperature is kept unchanged at 1200 ℃, then the pressure is continuously and uniformly pressurized at the speed of 0.04MPa/s, the uniform pressurization not only can compensate the pressure drop caused by phase change of pyrophyllite, but also can promote the diamond to grow up rapidly under the condition of full nutrition supply, thereby not only increasing the yield, but also improving the quality, and only needing 10 minutes to reach the main granularity of 70/80 needed in industry; the pressure is maintained and the temperature begins to be reduced when the pressure is increased to 89MPa, the temperature is reduced in a stepped temperature reduction mode, when the temperature is reduced by 200 ℃, the temperature is kept for 5 seconds, the diamond product is not affected by darkening of the diamond color caused by sudden cooling, the golden color of the diamond product is kept, the pressure begins to be relieved when the temperature is reduced to the room temperature, the pressure is relieved in a segmented mode when the pressure is relieved, the pressure is relieved to normal pressure after 5 seconds every 25MPa, and the pressure relief is completed.
Example 3
The concave-convex hexahedral top ultrahigh pressure sealing assembly in the above embodiment 1 is applied to a hexahedral top press, and the formed high pressure hexahedral top press can be used for the synthesis of diamond, and the process is as follows: putting the pyrophyllite synthetic block into a high-pressure cavity of the hexahedral press, pushing six pistons of the hexahedral press under the action of a supercharger, and performing idle stroke; enabling six hard alloy top hammers of the hexahedral top press to be in contact with pyrophyllite, filling liquid and pressurizing, communicating the overpressure to 75MPa by using the hexahedral top press to reach the pressure of 6MPa, keeping the pressure for 7min at the overpressure speed of about 0.7MPa/s, and pressurizing the pressure for 45s to the synthesis pressure of 88MPa, so that graphite columns (graphite powder and metal catalyst powder) in a synthesis cavity of the pyrophyllite synthesis block are fully melted, and graphite is fully converted; heating is started when the pressure is 48MPa in the pressurizing process from normal pressure to 75MPa, so that the condition that pyrophyllite cannot be sealed under the conditions of low pressure and high temperature to burn out is avoided, the temperature is increased to 1440 ℃ through 15 seconds, and heat is preserved, so that graphite and metal powder are mutually dissolved and mutually infiltrated; maintaining the pressure at 75MPa for 3 minutes, and reducing the temperature from 1400 ℃ to 1200 ℃ for a certain temperature to prevent diamond graphitization caused by overhigh temperature; the temperature is kept unchanged at 1200 ℃, then the pressure is continuously and uniformly pressurized at the speed of 0.04MPa/s, the uniform pressurization not only can compensate the pressure drop caused by phase change of pyrophyllite, but also can promote the diamond to grow up rapidly under the condition of full nutrition supply, thereby not only increasing the yield, but also improving the quality, and only needing 10 minutes to reach the main granularity of 70/80 needed in industry; the pressure is maintained and the temperature begins to be reduced when the pressure is increased to 98MPa, the temperature is reduced in a stepped temperature reduction mode, when the temperature is reduced by 200 ℃, the temperature is kept for 5 seconds, the diamond product is not affected by darkening of the diamond color caused by sudden cooling, the golden color of the diamond product is kept, the pressure begins to be relieved when the temperature is reduced to the room temperature, the pressure is relieved in a segmented mode when the pressure is relieved, the pressure is relieved to the normal pressure after 5 seconds every 25MPa, and the pressure relief is completed.
The present invention is not limited to the preferred embodiments described above, and any person skilled in the art will recognize that equivalent embodiments with modifications or variations can be made without departing from the scope of the invention.
The technical scheme of the invention is not limited to the specific embodiment, and all technical modifications made according to the technical scheme of the invention fall within the protection scope of the invention.
Claims (4)
1. The concave-convex six-sided top ultrahigh pressure sealing assembly is characterized by comprising a concave bottom piston, an inner convex working cylinder, a cylinder cover and a rear plug; the cylinder cover is connected to the inner convex working cylinder through bolts, two sealing rings are overlapped between the cylinder cover and the inner convex working cylinder, and the rear plug is connected to the center of the bottom surface outside the inner convex working cylinder through bolts;
the sealing structure is three O-shaped sealing rings which are circumferentially attached to the side wall of the concave bottom piston, a sealing groove is formed between each O-shaped sealing ring and the inner wall of the inner convex working cylinder, a radial annular oil storage groove is formed in the space between every two adjacent O-shaped sealing rings, and a reset rod is arranged between every two adjacent O-shaped sealing rings in a plugging manner;
the cylinder cover is of a step shape, the cylinder cover is contacted with the inner protruding working cylinder by the inner diameter of three O-shaped sealing rings, a piston built-in axial guide key slot is arranged on the inner diameter of the cylinder cover close to the front cavity of the inner protruding working cylinder, and an anti-rotation key is inserted in the corresponding axial guide key slot.
2. The concave-convex type six-sided ultra-high pressure sealing assembly according to claim 1, wherein the number of the reset rods is four, the reset rods are arranged in the oil storage tank in a clearance mode around the circumference, the reset rods are made of rubber materials to coat the reset springs, so that a closed structure is formed, and the outer sides of the coatings of the reset rods are fold wrinkled skins.
3. The concave-convex type six-face top ultrahigh pressure sealing assembly according to claim 1, wherein an oil inlet hole in the center of the inner convex type working cylinder is of a small-aperture structure, one port of the oil inlet hole is located in the center of the upper end face of the round table-shaped protrusion, the other port of the oil inlet hole is located in the center of the bottom end face of the inner convex type working cylinder, the oil inlet hole is communicated with the rear plug in a taper type sealing contact manner, and four fixing bolt holes are formed around the oil inlet hole in the bottom end face of the outer side of the inner convex type working cylinder and used for fixing the rear plug through bolts.
4. A diamond synthesis process, characterized by using a concave-convex hexahedral top ultrahigh pressure sealing assembly according to claim 1, comprising the steps of: placing the synthetic block into a high-pressure cavity of a hexahedral top press, pressurizing to 4-6MPa, communicating with an overpressure to 65-75MPa, maintaining the pressure for 4-7.6 minutes, pressurizing to 80-88MPa for 15-45s, heating the synthetic block when the pressure reaches 40-48MPa in the pressure change process, and heating the synthetic block to 1340-1440 ℃ for 10-15s and preserving heat; maintaining the pressure for 1.5-3min, and reducing the temperature from 1340-1440 ℃ to 1200-1300 ℃; the temperature is kept unchanged at 1200-1300 ℃, the pressure is continuously increased at the speed of 0.02-0.04MPa/s, the pressure is maintained and reduced when the pressure is increased to 89-98MPa, the pressure is reduced after the temperature is reduced to the room temperature, the pressure is relieved, and the synthesis is completed after the pressure is relieved to normal pressure.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810010344.9A CN107899513B (en) | 2018-01-05 | 2018-01-05 | Concave-convex hexahedral top ultrahigh pressure sealing assembly and diamond synthesis process |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810010344.9A CN107899513B (en) | 2018-01-05 | 2018-01-05 | Concave-convex hexahedral top ultrahigh pressure sealing assembly and diamond synthesis process |
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| CN107899513A CN107899513A (en) | 2018-04-13 |
| CN107899513B true CN107899513B (en) | 2024-02-06 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2810735Y (en) * | 2005-07-27 | 2006-08-30 | 湖南飞碟新材料有限责任公司 | Hinge type cubic press |
| CN2907883Y (en) * | 2006-05-15 | 2007-06-06 | 郑州人造金刚石及制品工程技术研究中心 | Cubic apparatus press assembly |
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| CN205503989U (en) * | 2016-03-24 | 2016-08-24 | 隋心 | Hydro -cylinder compensation formula sliding seal structure |
| CN207941487U (en) * | 2018-01-05 | 2018-10-09 | 焦作天宝桓祥机械科技有限公司 | A kind of concave-convex type cubic apparatus superhigh pressure sealing component |
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2018
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2810735Y (en) * | 2005-07-27 | 2006-08-30 | 湖南飞碟新材料有限责任公司 | Hinge type cubic press |
| CN2907883Y (en) * | 2006-05-15 | 2007-06-06 | 郑州人造金刚石及制品工程技术研究中心 | Cubic apparatus press assembly |
| CN201335152Y (en) * | 2008-04-10 | 2009-10-28 | 高满锴 | Universal ultra-high voltage sealing ring |
| CN201575138U (en) * | 2009-12-31 | 2010-09-08 | 桂林桂冶实业有限公司 | Piston for working cylinder of cubic hydraulic machine |
| CN101862622A (en) * | 2010-06-11 | 2010-10-20 | 郑州人造金刚石及制品工程技术研究中心有限公司 | Process for synthesizing diamond |
| CN201880519U (en) * | 2010-11-25 | 2011-06-29 | 河南金渠黄金股份有限公司 | Piston assembly for cubic press |
| CN205503989U (en) * | 2016-03-24 | 2016-08-24 | 隋心 | Hydro -cylinder compensation formula sliding seal structure |
| CN207941487U (en) * | 2018-01-05 | 2018-10-09 | 焦作天宝桓祥机械科技有限公司 | A kind of concave-convex type cubic apparatus superhigh pressure sealing component |
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| CN107899513A (en) | 2018-04-13 |
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