A graphite lubricated bearing for ships and its preparation method

Abstract

The present invention relates to a graphite lubricated bearing for ships and a preparation method thereof. The method comprises the following steps: pretreatment: adding a polymer precursor and a catalyst into a reactor, and after reaction, obtaining an ultra-high molecular thermosetting resin solution; modification: adding a solid lubricant and an alkali into the ultra-high molecular thermosetting resin solution, and after stirring, obtaining a modified ultra-high molecular thermosetting resin solution; gluing: impregnating the ultra-high molecular thermosetting resin solution onto a frame material to obtain a semi-cured polymer nanocomposite sheet; pressing: placing the semi-cured polymer nanocomposite sheet onto a press and pressing to obtain a graphite lubricated bearing for ships. Compared with the prior art, the present invention has the advantages of having stronger mechanical properties and dimensional stability, while ensuring a lower friction coefficient and volume wear under extreme working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a graphite lubricated bearing for ships and a preparation method thereof. Background Art

[0002] The stern bearing is a critical component of a ship's propulsion system shafting system. It not only bears the gravity loads of the tail shaft, propeller shaft, propeller, and its accessories, but also dynamic and transient impact loads generated during shafting operation and by the explosion of underwater attack weapons. Its performance significantly impacts the ship's technical and operational performance. Stern bearing lubrication technologies primarily include water lubrication and oil lubrication. Currently, military vessels all use water-lubricated stern bearings. Replacing oil lubrication with water not only enhances the ship's stealth during ocean voyages but also protects the marine environment from contamination by oil leaks. It is a key research area in the field of ship propulsion systems, both domestically and internationally. Furthermore, due to its relatively stable source, energy conservation, and environmental protection, water is the working medium with the greatest development potential.

[0003] Compared to oil lubrication, water lubrication offers the following advantages: 1. Improved cooling efficiency; 2. Simplified stern bearing lubrication systems; 3. Avoidance of oil leaks that could reduce a ship's stealth; 4. Environmental friendliness; and 5. Cost savings. High-quality water-lubricated bearings must not only demonstrate excellent load-bearing and friction performance, but also adapt to varying sea temperatures, varying levels of impurities and hard particles in seawater, and withstand transient and dynamic impacts. Therefore, key evaluation criteria for water-lubricated bearing materials include their water expansion coefficient, wet friction coefficient, and thermal expansion coefficient.

[0004] Currently, existing water-lubricated bearings can be broadly categorized by their use, including ironwood bearings, fabric-reinforced bakelite bearings, plywood bearings, rubber bearings, and hard polymer composite bearings. The applicant believes that, compared to other types of bearing materials, hard polymer composite bearings, due to their low water and thermal expansion, exhibit greater dimensional stability in marine environments with varying temperatures, ensuring a relatively stable bearing-shaft clearance and extending bearing service life. Under extreme operating conditions, their excellent self-lubricating and anti-wear properties ensure a low coefficient of friction even in temporary water shortages, significantly reducing the likelihood of bearing damage. Summary of the Invention

[0005] The purpose of the present invention is to overcome at least one of the defects of the above-mentioned prior art and to provide a graphite lubricated bearing for ships and its preparation method which has strong mechanical properties and dimensional stability while ensuring a low friction coefficient and volume wear under extreme working conditions.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for preparing a graphite-lubricated bearing for a ship, the method comprising the following steps:

[0008] Pretreatment: Add polymer precursor and catalyst into the reactor, and after reaction, obtain ultra-high molecular weight thermosetting resin solution;

[0009] Modification: adding a solid lubricant and an alkali to the ultrahigh molecular weight thermosetting resin solution and stirring to obtain a modified ultrahigh molecular weight thermosetting resin solution;

[0010] Gluing: impregnating the frame material with a solution of ultra-high molecular weight thermosetting resin to obtain a semi-cured polymer nanocomposite material sheet;

[0011] Pressing: Place the semi-cured polymer nanocomposite sheet on a press and press it to obtain a graphite lubricated bearing for ships.

[0012] Furthermore, the specific steps of preprocessing are:

[0013] Phenol and formaldehyde were added in sequence and heated to obtain the pre-material 1;

[0014] Slowly add the catalyst to the pre-material 1, stir, heat, and keep warm to polycondense into the pre-material 2.

[0015] The pre-material 2 is vacuum-dehydrated and gelled to form the pre-material 3;

[0016] Add solvent to the pre-material 3, continue stirring, and cool to obtain an ultra-high molecular weight thermosetting resin.

[0017] Furthermore, the molar ratio of phenol to formaldehyde is 1:(1.49-1.57), the mass of the catalyst is 1 / (10-20) of the phenol, and is generally 1 / 14 without special regulations. The catalyst is ammonia water with a concentration of 25-28wt%. The formaldehyde concentration is 36-38wt% and the density is about 1.1g / cm 3 About a solution.

[0018] Furthermore, when preparing the pre-material 1, the heating process is: first control the temperature at 50-80°C, then heat it to 83-85°C, then keep it at 85-90°C, keep it for 30-40 minutes, and then cool it to 40±5°C to obtain the pre-material 1.

[0019] Furthermore, when preparing the pre-material 2, the heating temperature is 60-70°C and the insulation time is 40-60min; when preparing the pre-material 3, the vacuum dehydration time is 2-4h and the vacuum degree is 0.9-1.4MPa; the gelation temperature is 70±5°C and the time is 80-120s.

[0020] Furthermore, in the modified ultra-high molecular weight thermosetting resin solution, the solid content of the ultra-high molecular weight thermosetting resin is 60-80wt%, the content of the solid lubricant is 6-8wt%, and the mass ratio of the solid lubricant to the alkali is (15-25):1, which is not particularly specified and is generally 20:1. The solid lubricant is a graphene powder, and the alkali comprises 1-2 kinds of sodium hydroxide, barium hydroxide, ammonia or zinc oxide. A strong base catalyst is conducive to increasing the methylol content and the compatibility with water of the resin. The addition of graphene, compared with existing pure sodium hydroxide, causes nano-sodium hydroxide particles in the sodium hydroxide / graphene nanocomposite material to be loaded onto the graphene sheet and, upon absorbing air, to become sodium carbonate. The sodium carbonate particles grow into large-grained sodium carbonate due to the connection of the graphene sheets, which can connect the gaps and reinforce the composite material on the one hand, and utilize the excellent mechanical properties of graphene on the other hand to significantly improve the strength of the reinforcement.

[0021] Furthermore, during the modification, the stirring time is 60-120 minutes, and after stirring, the mixture is boiled and dehydrated at 60-80° C. for 1-3 hours.

[0022] Furthermore, the gluing temperature is 70-100° C., the speed is 1.5-3.5 m / min, the frame material is a mesh woven fiber, and the glue content in the semi-cured polymer nanocomposite sheet is 60-75 wt%.

[0023] Furthermore, the initial pressing pressure is 40 kg, which is gradually increased to 50-150 kg. During pressing, the temperature is kept at 100-120° C. for 100-150 minutes, the cooling time is 1-3 hours, and the temperature of the cooled material is 30-40° C.

[0024] A graphite lubricated bearing for ships prepared by the method described above.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The present invention uses a reliable composite reinforced polymer material to replace oil-lubricated copper alloy and other materials. The water-lubricated structure complies with international environmental conventions and solves the problem of oil leakage and pollution when lubricated bearings are entangled in obstacles such as fishing nets during coastal navigation, which inevitably leads to immediate suspension of navigation for repairs, resulting in pollution of the navigation waters and high fines. In addition, the problem of oil leakage causing a decrease in the concealment of the ship, exposing the whereabouts, and causing huge losses to personnel and equipment.

[0027] (2) The present invention uses graphene to fuse several polymers with additives, fuse them into fibers, and then form a material similar to ironwood under high pressure to replace ironwood. Through a series of tests on the material, the Brinell hardness of the material is optimized, solving the problem of plow-shaped scratches and wear caused by foreign hard particles, hard foreign matter, and metal surface debris squeezed between the working surfaces of the bearing and the relative movement of the contact surfaces;

[0028] (3) In the present invention, while adding some additives to the resin synthetic material, the pressing temperature and pressure accuracy are strictly controlled, and the problems of the material swelling with water and increasing size affecting the bearing accuracy and affecting the normal operation of the shaft system are solved by improving the processing technology. The bearing can maintain the stability of the bearing lining material in a long-term seawater environment, and is not prone to aging under the action of long-term stress, and has strong anti-seizure ability, so that it can meet specific performance requirements;

[0029] (4) The present invention uses graphene polymer synthetic resin glue reinforced fiber, which has extremely strong penetration. The pressed graphene composite material is resistant to high temperature and wear, does not deform under high temperature and high pressure, and is noiseless;

[0030] (5) Comparative tests of the present invention with similar foreign products, such as Canadian Sailong and British Feilong T12, have shown that its comprehensive performance indicators are superior to those of imported bearing materials, and its operating temperature range is wider. It can serve as a domestic alternative to the serious wear problem of imported water-lubricated bearings that occurred in the early stages of typical ships. Its water expansion coefficient is close to that of the imported Feilong T12 material, and significantly better than that of Sailong. Its wet friction coefficient is significantly better than that of Sailong and Feilong T12 materials, fully ensuring the stability of the bearing lining material. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an electron microscope photograph of the material prepared in Example 1 after polishing. DETAILED DESCRIPTION

[0032] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0033] A graphite lubricated bearing for ships and a preparation method thereof, wherein the bearing material is prepared by the following steps:

[0034] 1. Pretreatment: First, add several polymer liquids according to the ratio and meter them into the reaction pot. Control the temperature, vacuum degree and catalyst in the middle. Specifically, add phenol and formaldehyde in order, heat and raise the temperature. Control the temperature at 50-80℃, then to 83-85℃, keep it at 85-90℃, keep it warm for 30-40 minutes, and then cool it to 40±5℃ to obtain pre-material 1. Slowly add the catalyst ammonia water to pre-material 1, stir, heat to 60-70℃, and then keep it warm. The reaction releases heat and the material automatically heats to boiling. Keep it warm for 40-60 minutes. After the film-forming material changes color, take a sample and condense it into pre-material 2. The mixture was vacuum-dehydrated and after 2-4 hours the temperature was raised to 70±5°C and the vacuum degree was 0.9-1.4 MPa. The final gelation time was 100 seconds and the sample was taken to form the pre-material 3. Methanol was added to the pre-material 3 and stirred continuously until the reaction solution was completed. The mixture was cooled to below 50°C to obtain an ultra-high molecular weight thermosetting resin. The condensation resin formed was cross-linked and cured. The molar ratio of phenol to formaldehyde was 1:(1.49-1.57). The density of the formaldehyde solution was 1.1 g / cm 3 , concentration 36-38wt%. Ammonia concentration 25-28wt%.

[0035] 2. Modification: Add graphene powder (a solid lubricant) and a strong base sodium hydroxide catalyst to the ultrahigh molecular weight thermosetting resin prepared in step 1. Stir continuously to remove bubbles. Stirring should last for 60-120 minutes. The modified boiling reaction should last for 1-3 hours. The dehydration temperature should be 60-80°C. The strong base catalyst helps increase the resin's hydroxymethyl content and compatibility with water. Compared to existing sodium hydroxide, the addition of graphene increases the sodium hydroxide nanoparticles in this sodium hydroxide / graphene nanocomposite by loading them onto the graphene sheets. As they absorb air, they transform into sodium carbonate. The sodium carbonate particles grow into large crystals due to the connection with the graphene sheets, bridging gaps and providing reinforcement. Furthermore, the excellent mechanical properties of graphene significantly enhance the strength of the reinforcement. The ultrahigh molecular weight thermosetting resin has a molecular weight of 500-1000 kg and a solids content of 60-80 wt%. The graphene powder content is 6-8 wt%.

[0036] 3. Gluing: The graphene nanocomposite material prepared in step 2 is impregnated into a fiber-reinforced frame material. The gluing temperature is 70-100°C, and the gluing speed is 1.5-3.5 m / min. After gluing, a semi-cured polymer nanocomposite sheet is formed. The frame material comprises a mesh-like woven fiber structure. The semi-cured polymer nanocomposite sheet contains 60-75 wt% glue.

[0037] 4. Pressing: Place the semi-cured polymer nanocomposite sheet formed in step 3 above into a press. Set the initial pressure to 40 kg, and gradually increase the pressure to 50-150 kg depending on the flow of the glue. Keep the temperature at 100-120°C for 100-150 minutes. Cool for 1-3 hours, then remove the material after cooling to 30-40°C.

[0038] Example 1

[0039] A graphite lubricated bearing for ships and a preparation method thereof, wherein the bearing material is prepared by the following steps:

[0040] Phenol and formaldehyde were added to the reaction pot in sequence, with a molar ratio of phenol to formaldehyde of 1:1.49. The mixture was heated to 85°C and kept warm, and then cooled to 35°C after 30 minutes.

[0041] Add 25wt% ammonia water, stir and heat to 60℃, the reaction exotherm causes the material to automatically heat to boiling, keep warm for 40 minutes, vacuum dehydrate, after 2 hours the temperature rises to 65℃, the vacuum degree is 0.9MPa.

[0042] Methanol was added and stirred continuously until the reaction solution was completed, and the solution was cooled to 45° C. to obtain 500-1000 kg of ultra-high molecular weight thermosetting resin.

[0043] Graphene powder and sodium hydroxide were added, and stirring was continued to remove bubbles. The stirring time was 60 minutes, the modified boiling reaction time was 1 hour, and the dehydration temperature was 60°C. The solid content of the ultra-high molecular weight thermosetting resin was 60-80% by weight, the content of the solid lubricant was 6-8% by weight, and the mass ratio of the solid lubricant to the alkali was 20:1.

[0044] Impregnated in fiber material with a density of 190g / m 2 Plant fiber, gluing temperature 70 ℃, gluing speed 1.5m / min, after gluing is completed, a semi-cured polymer nanocomposite material sheet is formed.

[0045] Place the mixture on a press with an initial pressure of 40 kg, increase the pressure to 80 kg, and keep the mixture at 100°C for 100 minutes. Cool the mixture for 1 hour and then discharge it at 30°C.

[0046] Example 2

[0047] A graphite lubricated bearing for ships and a preparation method thereof, wherein the bearing material is prepared by the following steps:

[0048] Phenol and formaldehyde were added sequentially to a reaction kettle at a molar ratio of 1:1.49. The mixture was heated to 85°C and held for 30 minutes before cooling to 35°C. 28wt% ammonia was added and stirred, heated to 60°C. The reaction exotherm caused the mixture to automatically boil. The mixture was held for 40 minutes and then vacuumed for dehydration. After 2 hours, the temperature returned to 65°C and the vacuum level was 0.9MPa. Methanol was added and stirred continuously until the reaction solution was complete. The mixture was then cooled to 45°C to produce 500-1000kg of ultra-high molecular weight thermosetting resin.

[0049] Add barium hydroxide, continue stirring and remove bubbles, the stirring time is 80 minutes, the modified boiling reaction time is 1.5 hours, and the dehydration temperature is 70°C.

[0050] It is immersed in the fiber material, the gluing temperature is 70°C, the gluing speed is 1.5m / min, and a semi-cured composite material sheet is formed after the gluing is completed.

[0051] Place the mixture on a press with an initial pressure of 40 kg, increase the pressure to 80 kg, and keep the mixture at 100°C for 100 minutes. Cool the mixture for 1 hour and then discharge it at 30°C.

[0052] Example 3

[0053] A graphite lubricated bearing for ships and a preparation method thereof, wherein the bearing material is prepared by the following steps:

[0054] Phenol and formaldehyde were added sequentially to a reaction kettle in a molar ratio of 1:1.57. The mixture was heated to 80°C, held at 85°C, and cooled to 35°C after 30 minutes. 28wt% ammonia water was added, stirred, and heated to 60°C. The reaction exotherm caused the mixture to automatically boil. The mixture was held at this temperature for 40 minutes, and then vacuumed and dehydrated. After 2 hours, the temperature returned to 65°C, and the vacuum level was 0.9MPa. Methanol was added and stirred continuously until the reaction solution was complete. The mixture was cooled to 45°C to produce 500-1000kg of ultra-high molecular weight thermosetting resin.

[0055] Graphene powder and sodium hydroxide were added, and the mixture was stirred continuously to remove bubbles. The stirring time was 60 min, the modified boiling reaction time was 1 h, and the dehydration temperature was 60°C.

[0056] It is immersed in the fiber material, the gluing temperature is 70°C, the gluing speed is 1.5m / min, and a semi-cured polymer nanocomposite material sheet is formed after the gluing is completed.

[0057] Place the mixture on a press with an initial pressure of 40 kg, increase the pressure to 80 kg, and keep the mixture at 100°C for 100 minutes. Cool the mixture for 1 hour and then discharge it at 30°C.

[0058] Example 4

[0059] A graphite lubricated bearing for ships and a preparation method thereof, wherein the bearing material is prepared by the following steps:

[0060] Phenol and formaldehyde were added sequentially to a reaction kettle in a molar ratio of 1:1.49. The mixture was heated to 50°C, held at 85°C, and cooled to 35°C after 30 minutes. 25wt% ammonia water was added, stirred, and heated to 60°C. The reaction exotherm caused the mixture to automatically boil. The mixture was held at this temperature for 40 minutes, and then vacuumed and dehydrated. After 2 hours, the temperature returned to 65°C, and the vacuum level was 0.9MPa. Methanol was added and stirred continuously until the reaction solution was complete. The mixture was then cooled to 45°C to produce 500-700kg of ultra-high molecular weight thermosetting resin.

[0061] Graphene powder and sodium hydroxide were added, and the mixture was stirred continuously to remove bubbles. The stirring time was 60 min, the modified boiling reaction time was 1 h, and the dehydration temperature was 60°C.

[0062] It is immersed in the fiber material, the gluing temperature is 80°C, the gluing speed is 2.5m / min, and a semi-cured polymer nanocomposite material sheet is formed after the gluing is completed.

[0063] Place the mixture on a press with an initial pressure of 40 kg, increase the pressure to 80 kg, and keep the mixture at 100°C for 100 minutes. Cool the mixture for 1 hour and then discharge it at 30°C.

[0064] For specific parameters not disclosed in Examples 2-4, please refer to Example 1.

[0065] The performance characteristics of Examples 1-4 are as follows:

[0066] Serial number Material name Example 1 Example 2 Example 3 Example 4 1 <![CDATA[Density g / cm 3 > 1.36 1.37 1.38 1.38 2 Compression strength MPa 154 60 157 158 3 Brinell hardness HBW 36.0 15.3 35.2 36.3 4 Water expansion coefficient% 0.25 0.19 0.26 0.26 5 Wet friction coefficient 0.08-0.15 0.08-0.18 0.08-0.16 0.08-0.18 6 <![CDATA[Coefficient of thermal expansion × 10 -6 / ℃]]> 32 33 34 34 7 Operating temperature ℃ -196～180℃ -196～180℃ -196～180℃ -196～180℃

[0067] It can be seen that a strong base catalyst is beneficial for increasing the hydroxymethyl content of the resin and its compatibility with water. The solid lubricant is graphite powder. The addition of graphene, compared to existing sodium hydroxide, allows the nano-sodium hydroxide particles in this sodium hydroxide / graphene nanocomposite to be loaded onto the graphene sheets. Upon absorbing air, they transform into sodium carbonate. The sodium carbonate particles, connected by the graphene sheets, grow into large crystals of sodium carbonate, which bridge gaps and reinforce the material. Furthermore, the excellent mechanical properties of graphene are utilized to significantly increase the strength of the reinforcement.

[0068] The performance comparison between the present invention and the prior art is as follows:

[0069] Serial number Material name Dragon Race Feilong T12 The present invention Testing standards 1 <![CDATA[Density g / cm 3 > 1.21 1.34 1.36-1.38 GB / T 1033.1 2 Compression strength MPa 149 35 154-158 GB / T 1448 3 Brinell hardness HBW 33 25 35.2-36.3 GB / T 231.1 4 Water expansion coefficient% 1.30 0.25 0.25-0.26 GB / T 1462 5 Wet friction coefficient 0.20-0.25 0.08-0.19 0.08-0.18 GB / T 3960 6 <![CDATA[Coefficient of thermal expansion × 10 -6 / °C]]> 148 50 32-34 ISO 11359 7 Operating temperature ℃ ＜60℃ ＜100℃ -196～180℃ -

[0070] Comparative testing of this material with similar foreign products, including Canadian Sailong and British Feilong T12, demonstrates that its comprehensive performance outperforms imported bearing materials and boasts a wider operating temperature range, making it a suitable domestic alternative to addressing the severe wear issues associated with imported water-lubricated bearings encountered in the early stages of typical shipbuilding. Its water expansion coefficient approaches that of the imported Feilong T12 material, significantly exceeding that of Sailong, and its wet friction coefficient significantly surpasses both Sailong and Feilong T12, fully ensuring the stability of the bearing lining material.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for preparing a graphite lubricated bearing for ships, characterized in that: The method comprises the following steps: Pretreatment: Add polymer precursor and catalyst into the reactor, and after reaction, obtain ultra-high molecular weight thermosetting resin solution; Modification: adding a solid lubricant and an alkali to an ultra-high molecular weight thermosetting resin solution and stirring the mixture to obtain a modified ultra-high molecular weight thermosetting resin solution; Gluing: impregnating the frame material with a solution of ultra-high molecular weight thermosetting resin to obtain a semi-cured polymer nanocomposite material sheet; Pressing: placing the semi-cured polymer nanocomposite sheet on a press to obtain a graphite lubricated bearing for ships; In the modified ultra-high molecular weight thermosetting resin solution, the solid content of the ultra-high molecular weight thermosetting resin is 60-80 wt%, the content of the solid lubricant is 6-8 wt%, and the mass ratio of the solid lubricant to the alkali is (15-25):1; the solid lubricant is graphene powder; and the alkali includes 1-2 of sodium hydroxide or barium hydroxide.

2. The method for preparing a graphite lubricated bearing for ships according to claim 1, characterized in that: The specific steps of preprocessing are: Phenol and formaldehyde were added in sequence and heated to obtain the pre-material 1; Slowly add the catalyst to the pre-material 1, stir, heat, and keep warm to polycondense into the pre-material 2; The pre-material 2 is vacuum-dehydrated and gelled to form the pre-material 3; Add solvent to the pre-material 3, continue stirring, and cool to obtain an ultra-high molecular weight thermosetting resin.

3. The method for preparing a graphite lubricated bearing for ships according to claim 2, characterized in that: The molar ratio of phenol to formaldehyde is 1: (1.49-1.57), the mass of the catalyst is 1 / (10-20) of phenol, and the catalyst is ammonia water with a concentration of 25-28wt%.

4. The method for preparing a graphite lubricated bearing for ships according to claim 2, characterized in that: When preparing the pre-material 1, the heating process is: first control the temperature at 50-80°C, then heat it to 83-85°C, then keep it at 85-90°C, keep it for 30-40 minutes, and then cool it to 40±5°C to obtain the pre-material 1.

5. The method for preparing a graphite lubricated bearing for ships according to claim 2, characterized in that: When preparing pre-material 2, the heating temperature is 60-70°C and the insulation time is 40-60 min; when preparing pre-material 3, the vacuum dehydration time is 2-4 h, the vacuum degree is 0.9-1.4 MPa; the gelation temperature is 70±5°C and the time is 80-120 s.

6. The method for preparing a graphite lubricated bearing for ships according to claim 1, characterized in that: During the modification, the stirring time is 60-120 min, and after stirring, the mixture is boiled and dehydrated at 60-80° C. for 1-3 h.

7. The method for preparing a graphite lubricated bearing for ships according to claim 1, characterized in that: The gluing temperature is 70-100° C., the speed is 1.5-3.5 m / min, the frame material is a mesh woven fiber, and the glue content in the semi-cured polymer nanocomposite sheet is 60-75 wt%.

8. The method for preparing a graphite lubricated bearing for ships according to claim 1, characterized in that: The initial pressing pressure is 40 kg, which is gradually increased to 50-150 kg. During pressing, the temperature is kept at 100-120° C. for 100-150 min, the cooling time is 1-3 h, and the temperature of the cooled material is 30-40° C.

9. A graphite lubricated bearing for ships prepared by the method according to any one of claims 1 to 8.

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