Method for producing high-performance main pump water-lubricated graphite bearing material from tertiary powder

Abstract

The invention discloses a method for producing a high-performance main pump water-lubricated graphite bearing material from tertiary powder. The method comprises the following steps: mixing superfine coke powder, graphite powder and asphalt according to a ratio, and carrying out flaking treatment; carrying out crushing and grinding treatment on the obtained material sheets to obtain pressed powder, carrying out compression molding on the pressed powder, carrying out roasting to obtain a blank, and carrying out grinding treatment on the blank to obtain first-stage powder; the first-stage powder, graphite powder and asphalt are mixed according to the proportion and then subjected to sheet rolling treatment, then rolled sheets are subjected to crushing and grinding treatment to obtain pressed powder, and the pressed powder is subjected to isostatic pressing to obtain a blank; graphitizing the obtained blank twice to obtain a semi-finished blank; impregnating the semi-finished blank with furan resin to obtain a finished blank; according to the invention, the internal structure of the graphite material matrix and the uniformity of pore distribution are improved by adopting a three-time powder production mode, the product strength is improved, and the obtained graphite material matrix has high volume density, low porosity, high bending strength and high compressive strength.

Description

Technical Field

[0001] This invention relates to the field of bearing material technology, and specifically to a method for producing high-performance main pump water-lubricated graphite bearing material through tertiary powdering. Background Technology

[0002] Bearings are essential components in modern machinery. Their main function is to support rotating mechanical parts, reduce the coefficient of friction during movement, and ensure rotational accuracy. Commonly used bearings include sliding bearings, rolling bearings, and spherical plain bearings. Sliding bearings operate under sliding friction. The lubrication methods for sliding bearings are mainly water lubrication and oil lubrication. Oil lubrication often results in oil leakage, which is highly polluting to the environment. Water-lubricated bearings use water as a lubricant and, compared to oil-lubricated bearings, have advantages such as being environmentally friendly and having low energy consumption, making them widely used in shipbuilding, pumps, and turbines.

[0003] In nuclear power plants, the main pump, as the only rotating equipment, primarily uses water lubrication. The quality of the water-lubricated bearing material is closely related to the safety and reliability of the nuclear pump. Given the harsh environment of nuclear power plants, characterized by high temperatures and radiation, current water-lubricated bearing materials are generally made from inorganic materials such as graphite or siliconized graphite. However, existing methods for preparing graphite bearing materials suffer from poor flexibility, low strength, and poor wear resistance. Under impact loads during use, they are prone to brittle fracture, thus affecting the safe operation of the nuclear pump. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for producing high-performance main pump water-lubricated graphite bearing material through a three-stage powdering process. The method employs a three-stage powdering process, a two-stage production process, and two graphitization processes to improve the uniformity of the internal structure of the product, enhance various performance indicators, and thereby improve the material's resistance to high-temperature and high-pressure wear and its resistance to radiation from radioactive media.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, a method for producing high-performance water-lubricated graphite bearing material for main pumps using a tertiary powder process is provided, comprising the following steps:

[0007] (1) Mix ultrafine coke powder, graphite powder and asphalt in a certain proportion and then roll them into sheets;

[0008] Carbon graphite is a particulate material, and the particle size and composition of the raw materials are crucial in the production process. Smaller particle sizes in the matrix raw materials require more binder during mixing. The binder evenly coats and wets the particle surface and pores, thus improving the plasticity and flowability of the mixed paste and enhancing the uniformity of the graphite matrix. Simultaneously, smaller raw material powder particle sizes result in more uniform coating of coke particles and particle surfaces during heating and mixing through the binder's wetting effect. During calcination, the coking of the binder between particles forms a 'skeleton' structure. Smaller particles result in a more abundant and stable 'skeleton' structure, ultimately leading to a better matrix structure and performance of the graphite material.

[0009] (2) The obtained material is crushed and ground to obtain pressed powder. The pressed powder is pressed into shape and then baked to obtain a blank, which is then ground to obtain a first-stage powder.

[0010] The primary purpose of the first-stage powder preparation is to thoroughly mix ultrafine pitch coke powder (D50≤5μm) with binder pitch. During mixing, the pitch fully penetrates the spaces between pitch coke powder particles, as well as the surface and pores of the powder. After calcination, a "skeleton" structure with higher mechanical strength is formed. By strengthening the basic raw material, the mechanical strength and other tribological properties of graphite materials are improved. Simultaneously, the first-stage preparation allows for secondary granulation of the raw material powder. After grinding, the powder particles become more uniform in size and shape. The secondary powder uses the first-stage powder as the base aggregate. Better particle size uniformity of the aggregate during calcination reduces the cracking rate of the product.

[0011] (3) Mix the first-stage powder, graphite powder and asphalt in proportion and then roll them into sheets. Then crush and grind the sheets to obtain pressed powder. The pressed powder is then isostatically pressed to obtain a blank.

[0012] Isostatic pressing is employed, ensuring uniform pressure on the surface of the product during the pressing process. This results in uniform flow and shrinkage of the pressed powder particles, leading to a more uniform particle size distribution. Consequently, the final graphite material exhibits a homogeneous internal structure and similar, non-directional properties, thus guaranteeing a product anisotropy ratio of 1.05:1.

[0013] (4) The blank obtained in (3) is roasted, impregnated with asphalt, and then graphitized for the first time. Then it is roasted and impregnated with asphalt multiple times and graphitized for the second time to obtain a semi-finished blank.

[0014] The purpose of multiple impregnation and baking is to densify the product. After multiple impregnation and baking, the product density and mechanical strength gradually increase, while the porosity inside the matrix gradually decreases. During the multiple impregnation and baking process, the binder asphalt cokes repeatedly inside the product. The coke from the binder coke gradually fills the pores inside the matrix. However, the residual carbon content of the binder is only about 40%, which cannot fill 100% of the pores inside the matrix. Therefore, after multiple impregnation and baking, some pores will remain inside the matrix, including open and closed pores. Therefore, the purpose of the first graphitization is to perform low-temperature graphitization on the product after multiple impregnation and baking. During the graphitization process, the carbon atoms inside the product transform from amorphous carbon to graphite. During the transformation, the carbon atoms inside the product are arranged from disordered to ordered. At the same time, the high temperature during the graphitization process will also cause the coke from the binder coke to transform again, and the matrix will release some volatiles again. Therefore, after the first graphitization, the product matrix shrinks in volume, the internal structure changes, the carbon atoms rearrange, and some pores inside the matrix will change from closed pores to open pores. Therefore, after the first graphitization, the internal structure of the product changes, and the number of pores in the matrix increases, which is more beneficial to the impregnation effect of the subsequent binder and to the increase of matrix density, thereby promoting the improvement of various properties of the final product. The purpose of the second graphitization is to meet the final performance requirements of the product by controlling the graphitization temperature.

[0015] (5) Impregnate the semi-finished blank with furan resin to obtain the finished blank.

[0016] One or more technical solutions of the present invention have the following beneficial effects:

[0017] This invention uses ultrafine powder (D50≦5μm) as the main raw material and employs a three-stage powdering, two-stage production, and two-stage graphitization process to improve the uniformity of the internal structure of the product, enhance various performance indicators, and thus improve the material's resistance to high-temperature and high-pressure wear and radiation. This invention uses isostatic pressing to improve the material's microstructure and reduce the anisotropy ratio of traditional pressing molding (to 1.05:1). This invention uses furan resin impregnation to improve the material's strength and wear resistance. This application improves the internal structure and pore distribution uniformity of the graphite matrix by using a three-stage powdering production method, enhancing product strength. The resulting graphite matrix has high bulk density, low porosity, high flexural strength, and high compressive strength.

[0018] The present invention also proposes to use carbon nanotubes as an additive, and limit the amount of carbon nanotubes added to a certain range, which can improve the internal structure and uniformity of pore distribution of graphite material matrix, improve product strength, and the obtained graphite material matrix has high bulk density, low porosity, high flexural strength and high compressive strength. Attached Figure Description

[0019] Figure 1 The flowchart shows the method for producing high-performance main pump water-lubricated graphite bearing material using tertiary powder processing in Examples 1-3.

[0020] Figure 2 This is a flowchart of the method for producing high-performance main pump water-lubricated graphite bearing material using tertiary powder processing, as described in Examples 4-6. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] In a typical embodiment of the present invention, a method for producing high-performance main pump water-lubricated graphite bearing material through tertiary powdering is proposed, such as... Figure 1 As shown, it includes the following steps:

[0023] (1) The ultrafine coke powder, graphite powder, and pitch are mixed in a certain proportion and then rolled into sheets:

[0024] Specifically, the content of ultrafine coke powder is 80-90 wt%, the particle size of ultrafine coke powder is less than 10 μm, the content of graphite powder is 10-20 wt%, the particle size of graphite powder is less than 45 μm, the asphalt addition temperature is 160-180℃, the asphalt softening point is 80-105℃, the residual carbon rate is 35-45 wt%, and the asphalt addition mass is 40-50% of the total mass of the mixture.

[0025] The content of ultrafine coke powder plays a crucial role in the performance of the final product. The content of ultrafine coke powder should be controlled at 80-90 wt%. If the content is lower than this range, the product performance will decline. If it is higher than this range, it will cause the product to crack during the roasting process in the semi-finished product production process, resulting in a low yield.

[0026] The particle size of ultrafine coke powder has a significant impact on the final material properties. When the particle size of ultrafine coke powder is controlled below 10μm, under the same formulation, the finer the raw material powder particles, the higher the density of the graphitized material, the greater the mechanical strength, and the better the mechanical and thermal properties of the final product. Conversely, the coarser the raw material powder particles, the lower the material density, the worse the mechanical properties, and the worse the mechanical and thermal properties.

[0027] Graphite powder is a good conductor of heat and electricity. The content of graphite powder is controlled at 10-20 wt%. The purpose of adding this amount of graphite powder is to promote the thermal and electrical conductivity of the blank matrix during the heating process of baking and graphitization. At the same time, a certain amount of graphite powder can promote the shrinkage of the product during the heating process of baking and graphitization, thereby improving the various properties of the product. Graphite powder itself has low strength and less developed pores compared to pitch coke. If too much graphite powder is added, it will reduce the mechanical strength of the product.

[0028] Furthermore, during the mixing process, ultrafine coke powder and graphite powder are first placed in a mixing pot and stirred continuously until evenly mixed. At the same time, the powder is heated so that it gradually rises to 100-120°C within 1 hour. Then, asphalt is added, and after kneading for 2 hours, the mixture is removed from the pot to obtain a kneaded paste.

[0029] Furthermore, the obtained mixed paste is rolled at a temperature of 130-150℃ to obtain sheet material with a sheet thickness of less than 2mm.

[0030] (2) The obtained material flakes are crushed and ground to obtain pressed powder. The pressed powder is pressed into shape and then fired to obtain a blank, which is then ground to obtain a first-stage powder.

[0031] Specifically, the particle size of the pressed powder after crushing and grinding is below 45μm, the pressing and molding pressure is 80-100MPa, and the calcination process is heated to 850℃ at a heating rate of 10-15℃ / h and held for 8-12h, resulting in a first-stage powder with a particle size below 60μm.

[0032] (3) After mixing the first-stage powder, graphite powder, and asphalt in a certain proportion, the mixture is rolled into sheets. Then, the rolled sheets are crushed and ground to obtain pressed powder. The pressed powder is then subjected to isostatic pressing to obtain a blank.

[0033] Specifically, during the mixing process, the first-stage powder and graphite powder are first put into a kneading pot and heated and kneaded for 60-120 minutes until the temperature rises to 120-130℃. Then, asphalt is added and heated and kneaded for 2 hours until the temperature rises to 160±10℃ before being removed from the pot to obtain a paste. The obtained paste is then quickly rolled at a temperature of 130-150℃ to obtain sheets with a thickness of less than 2mm.

[0034] Alternatively, in step (3), during the mixing process, the first stage powder and graphite powder are first put into the mixing pot and cold mixed for 10-30 minutes, then 0.5-3wt% of carbon nanotubes are added and heated and mixed for 60-120 minutes until the temperature rises to 120-130℃, then asphalt is added and heated and mixed for 2 hours until the temperature rises to 160±10℃ and the paste is obtained.

[0035] Preferably, the average diameter of the carbon nanotubes is 10-30 nm, and the particle size of the carbon nanotubes is less than 10 μm.

[0036] Furthermore, the first-stage powder content is 80-90 wt%, the graphite powder content is 10-20 wt%, the graphite powder particle size is below 45 μm, the asphalt softening point is 80-105℃, the asphalt addition temperature is 160-180℃, the residual carbon rate is 35-45 wt%, and the asphalt addition mass is 55-65% of the total mass of the mixture.

[0037] Furthermore, the particle size of the pressed powder after crushing and grinding is below 70μm, and the static pressing pressure is 150-200MPa.

[0038] (4) The billet obtained in (3) is calcined, impregnated with asphalt, and then graphitized for the first time. Then, it is calcined and impregnated with asphalt multiple times and then graphitized for the second time to obtain a semi-finished billet:

[0039] Specifically, the process involves alternating between baking and pitch impregnation before the first graphitization, for example: first baking, first pitch impregnation, second baking, second pitch impregnation, third baking, third pitch impregnation, and fourth baking followed by the first graphitization. The conditions for the first baking treatment are: heating to 1100℃ at a heating rate of 2-5℃ / h and holding at that temperature for 30 hours; the conditions for the remaining baking treatments are: heating to 900℃ at a heating rate of 5-10℃ / h and holding at that temperature for 10 hours.

[0040] Furthermore, the asphalt impregnation treatment conditions are as follows: at a temperature of 180-300℃ and a pressure of 1-3MPa, asphalt is used as the impregnating agent for impregnation treatment for 10-20 hours.

[0041] Furthermore, the conditions for the first graphitization treatment were: graphitization temperature of 2000-2200℃, and holding at that temperature for 5 hours.

[0042] Furthermore, the initial graphitization process involves alternating baking and pitch impregnation multiple times. For example, a fourth pitch impregnation, a fifth baking, and a fifth impregnation are performed. A sixth baking, a sixth pitch impregnation, a seventh baking, followed by a second graphitization. The baking conditions are: heating to 900℃ at a rate of 5-20℃ / h and holding for 10 hours; the pitch impregnation conditions are: impregnation with pitch as the impregnating agent at a temperature of 180-300℃ and a pressure of 1-3MPa for 10-20 hours.

[0043] Furthermore, the conditions for the second graphitization treatment were: graphitization temperature of 2200-2500℃, and holding at that temperature for 5 hours.

[0044] (5) Impregnate the semi-finished blank with furan resin to obtain the finished blank. Specifically, the impregnation pressure is 2MPa and the impregnation time is 20h.

[0045] The parameter range in the water-lubricated graphite bearing material preparation method provided in this embodiment is applicable to the preparation of water-lubricated graphite bearing materials for nuclear power main pumps. If the above technical parameters are deviated from or changed, the performance of the final water-lubricated graphite bearing material will be affected, and its physical and chemical properties, mechanical properties, thermal properties and other properties will change, making it unsuitable for the actual operating conditions of the water-lubricated graphite bearing material.

[0046] Example 1:

[0047] (1) First, put ultrafine coke powder with a particle size of less than 10μm (D50≦5μm) and a content of 90%wt% of the total dry powder of the mixture and graphite powder with a particle size of less than 45μm and a content of 10%wt% of the total dry powder of the mixture into a kneading pot and stir and heat to mix evenly. After the temperature of the powder gradually rises to 120℃ within 1 hour, add asphalt with a softening point of 85℃, a residual carbon rate of 41%, and a temperature of 170℃ into the kneading pot at 50wt% of the total dry powder mass in the pot. After heating and kneading for 2 hours, the temperature of the powder in the pot reaches 170℃ and is removed from the pot. Then, roll the powder at 150℃ to obtain a sheet with a thickness of 2mm. After the sheet is naturally cooled, crush and grind the sheet to a particle size of less than 45μm to make pressed powder. The pressed powder is then molded under a pressure of 80MPa to obtain blank A.

[0048] (2) The obtained billet A was heated to 850℃ at a heating rate of 15℃ / h and held at that temperature for 10h for the first firing, resulting in a bulk density of 1.24 g / cm³. 3 The billet B is crushed and ground to obtain a first-stage powder C with a particle size of less than 60μm.

[0049] (3) Place 90wt% of the first-stage powder C and 10wt% of the total dry powder of the mixture into a mixing pot and heat and knead for 120 min. After the temperature rises to 120℃, add 60wt% of the total mass of the powder in the pot, which has a softening point of 85℃, a residual carbon content of 41wt%, and a temperature of 170℃. Heat and mix for 2 h. After the temperature gradually reaches 170℃, remove the mixture from the pot and roll it into a sheet at 150℃. The sheet thickness is 2mm. After the sheet cools naturally, crush and grind it to a particle size of less than 70μm to make pressed powder. The pressed powder is subjected to isostatic pressing at a pressure of 150MPa to obtain blank D.

[0050] (4) The obtained blank D is subjected to a first firing, a first impregnation, a second firing, a second impregnation, a third firing, a third impregnation, a fourth firing, and a first graphitization treatment to obtain blank E. The obtained blank E is subjected to a fourth impregnation, a fifth firing, a fifth impregnation, a sixth firing, a sixth impregnation, a seventh firing, and a second graphitization treatment to obtain product F with a bulk density of 1.91 g / cm3, a porosity of 3.6%, a flexural strength of 65.3 MPa, and a compressive strength of 170.4 MPa.

[0051] The first calcination treatment conditions were: heating to 1100℃ at a heating rate of 3℃ / h and holding for 30h. The second, third, fourth, fifth, sixth, and seventh calcination treatment conditions were: heating to 900℃ at a heating rate of 10℃ / h and holding for 10h. The first, second, third, fourth, fifth, and sixth asphalt impregnation treatment conditions were: impregnation with asphalt as the impregnating agent at a temperature of 200℃ and a pressure of 3MPa for 20h. The first graphitization treatment conditions were: graphitization temperature of 2000℃ and holding for 5h. The second graphitization treatment conditions were: graphitization temperature of 2300℃ and holding for 5h.

[0052] (5) The obtained product F is impregnated with furan resin at an impregnation pressure of 2MPa for 20h to obtain the finished product.

[0053] Example 2:

[0054] (1) First, 90% wt% of ultrafine coke powder with a particle size of less than 10 μm (D50≦5 μm) and 10% wt% of graphite powder with a particle size of less than 45 μm are placed in a kneading pot and stirred and heated to mix evenly. After the temperature of the powder gradually rises to 120℃ within 1 hour, asphalt with a softening point of 85℃, a residual carbon rate of 41%, and a temperature of 170℃ is added to the kneading pot at 50 wt% of the total mass of the dry powder in the pot. After heating and kneading for 2 hours, the temperature of the powder in the pot reaches 170℃ and is removed from the pot. Then, it is rolled into sheets at 150℃ with a sheet thickness of 2 mm. After the sheets are naturally cooled, they are crushed and ground to a particle size of less than 45 μm to make pressed powder. The pressed powder is then molded under a pressure of 80 MPa to obtain blank A.

[0055] (2) The obtained billet A was heated to 850℃ at a heating rate of 15℃ / h and held at that temperature for 10h for the first firing, resulting in a bulk density of 1.23 g / cm³. 3 The billet B is crushed and ground to obtain a first-stage powder C with a particle size of less than 60μm.

[0056] (3) Place 85wt% of the first-stage powder C and 15wt% of the total dry powder of the mixture into a mixing pot and heat and knead for 120 min. After the temperature rises to 120℃, add 60wt% of the total mass of the powder in the pot, which has a softening point of 85℃, a residual carbon content of 41wt%, and a temperature of 170℃, into the mixing pot and heat and mix evenly for 2 h. After the temperature gradually reaches 170℃, remove the mixture from the pot and roll it into a sheet at 150℃. The sheet thickness is 2mm. After the sheet cools naturally, crush and grind it to a particle size of less than 70μm to make pressed powder. The pressed powder is subjected to isostatic pressing at a pressure of 150MPa to obtain blank D.

[0057] (4) The obtained blank D is subjected to a first firing, a first impregnation, a second firing, a second impregnation, a third firing, a third impregnation, a fourth firing, and a first graphitization treatment to obtain E. The obtained blank E is subjected to a fourth impregnation, a fifth firing, a fifth impregnation, a sixth firing, a sixth impregnation, a seventh firing, and a second graphitization treatment to obtain product F with a density of 1.86 g / cm3, a porosity of 7.4%, a flexural strength of 56.2 MPa, and a compressive strength of 158.6 MPa.

[0058] The first calcination treatment conditions were: heating to 1100℃ at a heating rate of 3℃ / h and holding for 30h. The second, third, fourth, fifth, sixth, and seventh calcination treatment conditions were: heating to 900℃ at a heating rate of 10℃ / h and holding for 10h. The first, second, third, fourth, fifth, and sixth asphalt impregnation treatment conditions were: impregnation with asphalt as the impregnating agent at a temperature of 200℃ and a pressure of 3MPa for 20h. The first graphitization treatment conditions were: graphitization temperature of 2000℃ and holding for 5h. The second graphitization treatment conditions were: graphitization temperature of 2300℃ and holding for 5h.

[0059] (5) The obtained product F is subjected to impregnation treatment with furan resin at an impregnation pressure of 2MPa and an impregnation time of 20h.

[0060] Example 3:

[0061] (1) First, 90% wt% of ultrafine coke powder with a particle size of less than 10 μm (D50≦5 μm) and 10% wt% of graphite powder with a particle size of less than 45 μm are placed in a kneading pot and stirred and heated to mix evenly. After the temperature of the powder gradually rises to 120℃ within 1 hour, asphalt with a softening point of 85℃, a residual carbon rate of 41%, and a temperature of 170℃ is added to the kneading pot at 50 wt% of the total mass of the dry powder in the pot. After heating and kneading for 2 hours, the temperature of the powder in the pot reaches 170℃ and is removed from the pot. Then, it is rolled into sheets at 150℃ with a sheet thickness of 2 mm. After the sheets are naturally cooled, they are crushed and ground to a particle size of less than 45 μm to make pressed powder. The pressed powder is then molded under a pressure of 80 MPa to obtain blank A.

[0062] (2) The obtained billet A was heated to 850℃ at a heating rate of 15℃ / h and held at that temperature for 10h for the first firing to obtain a bulk density of 1.25g / cm³. 3 The billet B is crushed and ground to obtain a first-stage powder C with a particle size of less than 60μm.

[0063] (3) Place 80wt% of the first-stage powder C and 20wt% of the total dry powder of the mixture into a mixing pot. Heat and knead for 120 min. After the temperature rises to 120℃, add 60wt% of the asphalt with a softening point of 85℃, a residual carbon content of 41wt%, and a temperature of 170℃ into the mixing pot. Heat and mix evenly for 2 h. After the temperature gradually reaches 170℃, remove from the pot. Then roll the material into sheets at 150℃. The sheet thickness is 2mm. After the sheet cools naturally, crush and grind it to a particle size of less than 70μm to make pressed powder. The pressed powder is subjected to isostatic pressing at a pressure of 150MPa to obtain blank D.

[0064] (4) The obtained blank D is subjected to a first firing, a first impregnation, a second firing, a second impregnation, a third firing, a third impregnation, a fourth firing, and a first graphitization treatment to obtain blank E. The obtained blank E is subjected to a fourth impregnation, a fifth firing, a fifth impregnation, a sixth firing, a sixth impregnation, a seventh firing, and a second graphitization treatment to obtain product F with a density of 1.80 g / cm3, a porosity of 9%, a flexural strength of 48.3 MPa, and a compressive strength of 153.3 MPa.

[0065] The first calcination treatment conditions were: heating to 1100℃ at a heating rate of 3℃ / h and holding for 30h. The second, third, fourth, fifth, sixth, and seventh calcination treatment conditions were: heating to 900℃ at a heating rate of 10℃ / h and holding for 10h. The first, second, third, fourth, fifth, and sixth asphalt impregnation treatment conditions were: impregnation with asphalt as the impregnating agent at a temperature of 200℃ and a pressure of 3MPa for 20h. The first graphitization treatment conditions were: graphitization temperature of 2000℃ and holding for 5h. The second graphitization treatment conditions were: graphitization temperature of 2300℃ and holding for 5h.

[0066] (5) The obtained product F is subjected to impregnation treatment with furan resin at an impregnation pressure of 2MPa and an impregnation time of 20h.

[0067] Example 4

[0068] Unlike Example 1, carbon nanotubes were added in step (3), such as Figure 2 Specifically, it is shown as follows:

[0069] First-stage powder C, comprising 90 wt% of the total dry powder of the mixture, and graphite powder, comprising 10 wt% of the total dry powder of the mixture with a particle size of less than 45 μm, were placed in a mixing pot and cold-mixed for 20 minutes. Then, carbon nanotubes with an average tube diameter of 10-30 nm, a particle size of less than 10 μm, and a content of 0.5 wt% of the total powder mass in the pot were added and heated and kneaded for 120 minutes until the temperature reached 120°C. Asphalt with a softening point of 85°C, a residual carbon content of 41 wt%, and a temperature of 170°C was added to the mixing pot at 60 wt% of the total powder mass in the pot and heated and mixed evenly for 2 hours until the temperature gradually reached 170°C. The mixture was then removed from the pot and rolled into sheets at 150°C with a sheet thickness of 2 mm. After the sheets were naturally cooled, they were crushed and ground to a particle size of less than 70 μm to form pressed powder. The pressed powder was then subjected to isostatic pressing at a pressure of 150 MPa to obtain blank D.

[0070] Example 5

[0071] The difference in Example 2 is that carbon nanotubes were added in step (3), specifically:

[0072] First-stage powder C, comprising 90 wt% of the total dry powder of the mixture, and graphite powder, comprising 10 wt% of the total dry powder of the mixture with a particle size of less than 45 μm, were placed in a mixing pot and cold-mixed for 20 minutes. Then, carbon nanotubes with an average tube diameter of 10-30 nm, a particle size of less than 10 μm, and a content of 2 wt% of the total powder mass in the pot were added and heated and kneaded for 120 minutes until the temperature reached 120°C. Asphalt with a softening point of 85°C, a residual carbon content of 41 wt%, and a temperature of 170°C was added to the mixing pot at 60 wt% of the total powder mass in the pot and heated and mixed evenly for 2 hours until the temperature gradually reached 170°C. The mixture was then removed from the pot and rolled into sheets at 150°C with a sheet thickness of 2 mm. After the sheets were naturally cooled, they were crushed and ground to a particle size of less than 70 μm to form pressed powder. The pressed powder was then subjected to isostatic pressing at a pressure of 150 MPa to obtain blank D.

[0073] Example 6

[0074] The difference in Example 3 is that carbon nanotubes were added in step (3), specifically:

[0075] First-stage powder C, comprising 90 wt% of the total dry powder of the mixture, and graphite powder, comprising 10 wt% of the total dry powder of the mixture with a particle size of less than 45 μm, are placed in a mixing pot and cold-mixed for 20 minutes. Then, carbon nanotubes with an average tube diameter of 10-30 nm, a particle size of less than 10 μm, and a content of 3 wt% of the total powder mass in the pot are added and heated and kneaded for 120 minutes until the temperature reaches 120°C. Asphalt with a softening point of 85°C, a residual carbon content of 41 wt%, and a temperature of 170°C is added to the mixing pot at 60 wt% of the total powder mass in the pot and heated and mixed evenly for 2 hours until the temperature gradually reaches 170°C. The mixture is then removed from the pot and rolled into sheets at 150°C with a sheet thickness of 2 mm. After the sheets are naturally cooled, they are crushed and ground to a particle size of less than 70 μm to form pressed powder. The pressed powder is then subjected to isostatic pressing at a pressure of 150 MPa to obtain blank D.

[0076] Comparison of test results

[0077]

[0078]

[0079] The test results above show that the nuclear pump water-lubricated bearing material obtained by the preparation method provided in this application has good comprehensive performance, and all its properties are superior to those of the prior art.

[0080] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method of producing a high performance main pump water lubricated graphite bearing material from a triabasic powder, characterised in that, The method comprises the following steps: (1) mixing superfine coke powder, graphite powder and pitch according to a proportion, and then performing tabletting treatment; (2) performing crushing and grinding treatment on the obtained tablet to obtain a pressed powder, and performing grinding treatment on the obtained pressed powder to obtain a first-stage powder; (3) mixing the first-stage powder, graphite powder and pitch according to a proportion, and then performing tabletting treatment, and then performing crushing and grinding treatment on the tablet to obtain a pressed powder, and then performing isostatic pressing forming on the pressed powder to obtain a blank; (4) performing baking and pitch impregnation on the blank obtained in the step (3), and then performing first graphitization, and then performing multiple times of baking and pitch impregnation, and then performing second graphitization to obtain a semi-finished blank; (5) impregnating furan resin on the semi-finished blank to obtain a finished blank.

2. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette according to claim 1, wherein, In the step (1), the superfine coke powder and the graphite powder are firstly put into a kneading pot and continuously stirred and mixed, and meanwhile, the material powder is gradually heated to 100-120 DEG C within 1 hour, and then the pitch is added, and the kneading is performed for 2 hours to obtain a kneaded paste.

3. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as claimed in claim 2 wherein, In the step (1), the content of the superfine coke powder is 80-90 wt%, the particle size of the superfine coke powder is less than 10 μm, the content of the graphite powder is 10-20 wt%, the particle size of the graphite powder is less than 45 μm, the pitch adding temperature is 160-180 DEG C, the pitch softening point is 80-105 DEG C, and the carbon residue rate is 35-45 wt%; the pitch adding quality is 40-50% of the total mass of the mixture of the superfine coke powder and the graphite powder.

4. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as recited in claim 1 wherein, In the step (2), the particle size of the pressed powder after the crushing and grinding treatment is less than 45 μm, the pressing forming pressure is 80-100 MPa, and the baking process conditions are that the temperature is heated to 850 DEG C at a heating rate of 10-15 DEG C / h, and the temperature is kept for 8-12 h.

5. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as recited in claim 1 wherein, In the step (3), the first-stage powder and the graphite powder are firstly put into a kneading pot and heated and kneaded for 60-120 min, and then the temperature is raised to 120-130 DEG C, and then the pitch is added and heated and kneaded for 2 h, and then the temperature is raised to 160±10 DEG C to obtain a paste; Alternatively, in the step (3), the first-stage powder and the graphite powder are firstly put into a kneading pot and cold-kneaded for 10-30 min, and then 0.5-3 wt% of carbon nanotubes are added and heated and kneaded for 60-120 min, and then the temperature is raised to 120-130 DEG C, and then the pitch is added and heated and kneaded for 2 h, and then the temperature is raised to 160±10 DEG C to obtain a paste; Preferably, the average tube diameter of the carbon nanotubes is 10-30 nm, and the particle size of the carbon nanotubes is less than 10 μm.

6. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as claimed in claim 5 wherein, In the step (3), the content of the first-stage powder is 80-90 wt%, the content of the graphite powder is 10-20 wt%, the particle size of the graphite powder is less than 45 μm, the pitch softening point is 80-105 DEG C, the pitch adding temperature is 160-180 DEG C, the carbon residue rate is 35-45 wt%, and the pitch adding quality is 55-65% of the total mass of the mixture of the first-stage powder and the graphite powder.

7. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as recited in claim 1 wherein, In the step (3), the particle size of the pressed powder after the crushing and grinding treatment is less than 70 μm, and the isostatic pressing forming pressure is 150-200 MPa.

8. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as recited in claim 1 wherein, In step (4), the first-time roasting and pitch impregnation are alternately performed for multiple times, the first-time roasting treatment condition is: heating to 1100℃ at a heating rate of 2-5℃ / h, and keeping for 30h, and the rest of the roasting treatment condition is: heating to 900℃ at a heating rate of 5-10℃ / h, and keeping for 10h.

9. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as claimed in claim 8 wherein, In step (4), the pitch impregnation treatment condition is: impregnating treatment for 10-20h under the condition that the temperature is 180-300℃ and the pressure is 1-3MPa, and the impregnating agent is pitch. Further, the first-time graphitization treatment condition is: graphitization temperature is 2000-2200℃, and keeping for 5h.

10. The method of producing high performance main pump water lubricated graphite bearing material from a triabriquette as recited in claim 1 wherein, In step (4), the second-time roasting and pitch impregnation are alternately performed for multiple times, the roasting treatment condition is: heating to 900℃ at a heating rate of 5-20℃ / h, and keeping for 10h, and the pitch impregnation treatment condition is: impregnating treatment for 10-20h under the condition that the temperature is 180-300℃ and the pressure is 1-3MPa, and the impregnating agent is pitch. Further, the second-time graphitization treatment condition is: graphitization temperature is 2200-2500℃, and keeping for 5h.

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