A surface strengthening method suitable for low-temperature steel friction pairs of complex configuration polar ships

Abstract

The application discloses a surface strengthening method suitable for low-temperature steel friction pairs of polar ship with complex configuration, and aims at solving the problems of insufficient surface wear resistance of the friction pairs and difficulty in surface strengthening in the existing polar ship with complex configuration.The surface strengthening method of the low-temperature steel friction pairs comprises the following steps: firstly, polishing and ultrasonic cleaning are conducted on the low-temperature steel friction pair materials; secondly, nano-diamond particle powder and spherical hard ceramic particles are mixed by ball milling; thirdly, a nickel-based plating solution is prepared; fourthly, supersonic particle bombardment treatment is conducted on the surface of the clean friction pair materials; fifthly, a nickel-based plating layer is prepared by adopting a chemical plating or brush plating process; sixthly, the step four and the step five are repeated for multiple times; seventhly, a composite plating solution is prepared; and eighthly, a self-lubricating coating is prepared.The application prepares a multilayer composite structure coating comprising a hardening layer, an alloy layer and a self-lubricating layer, the coating has good combination performance, high hardness and wear resistance, and is suitable for the low-temperature steel friction pairs of the polar ship with complex configuration.

Description

Technical Field

[0001] This invention belongs to the field of machining and surface modification, specifically relating to a method for surface strengthening of low-temperature steel friction pairs for complex polar ships. Background Technology

[0002] With the development and utilization of marine resources, the importance of polar exploration is increasing, and polar marine engineering has become a key area of ​​development for my country's marine economy. Currently, the polar development environment is extremely harsh, posing a significant challenge to the long-term stable operation of ship components. In particular, metal friction pairs of various power components are prone to increased brittleness and decreased wear resistance in low-temperature environments. Furthermore, for some complex low-temperature steel friction pairs, general surface strengthening technologies are insufficient to fully cover them, resulting in strengthening dead zones.

[0003] Supersonic particle bombardment (SFPB) technology is a surface strengthening technology that has emerged in recent years. It can plan the path according to the material configuration and solve the problem of strengthening dead zones in complex configurations. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of insufficient wear resistance and difficulty in surface strengthening of complex-configured friction pairs in existing polar ships, and to provide a surface strengthening method for low-temperature steel friction pairs in complex-configured polar ships.

[0005] This invention relates to a surface strengthening method for cryogenic steel friction pairs in complex polar vessels, implemented according to the following steps:

[0006] 1. Grinding and ultrasonic cleaning are performed on the low-temperature steel friction pair material to obtain a clean low-temperature steel friction pair material;

[0007] 2. The nano-diamond particles and spherical hard ceramic particles are mixed at a mass ratio of 1:15-1:30. The powder is then mixed evenly using a ball mill. After mixing, the powder is dried and preheated. The preheated powder is then placed into the cavity of the supersonic particle bombardment device.

[0008] 3. Based on the shape of the friction pair and its service conditions, formulate a nickel-based plating solution using either electroplating or chemical plating processes;

[0009] IV. Using a supersonic particle bombardment device, adjust the gas pressure during the supersonic particle bombardment process to 1.0-1.5MPa, the jet speed to 340-370m / s, and the bombardment angle to 30°-90°, and perform supersonic particle bombardment treatment on the clean surface of the friction pair material to obtain a friction pair material with a nano-hardened reinforcing layer.

[0010] V. Using a nickel-based plating solution, a nickel-based plating layer is prepared on the friction pair material with a nano-hardened reinforcing layer by chemical plating or electroplating processes.

[0011] 6. Repeat steps four and five multiple times to obtain a friction pair material with multiple reinforcement layers;

[0012] 7. Add a lubricating phase to the nickel-based plating solution to obtain a composite plating solution;

[0013] 8. Using chemical plating or electroplating processes and composite plating solutions, a self-lubricating coating is prepared on the surface of friction pair materials with multiple reinforcement layers to complete the surface strengthening of low-temperature steel friction pairs.

[0014] The lubricating phase mentioned in step seven is graphene oxide, nano-sized MoS2, nano-silver, or nano-copper.

[0015] This invention addresses the complex configuration of cryogenic steel friction pairs in marine vessels by proposing a surface strengthening method for such pairs in polar vessels. Based on a supersonic particle bombardment device equipped with a robotic arm, multi-angle path planning is possible to achieve surface strengthening without dead angles and achieve an overall strengthening effect. Furthermore, chemical plating and electroplating technologies are combined to prepare a multi-layered composite structure consisting of a hardened layer, an alloy layer, and a self-lubricating layer, thereby improving the wear resistance, hardness, and service life of the friction pair surface.

[0016] This invention, based on supersonic particle bombardment technology, electroplating technology, and chemical plating technology, designs a multi-layer composite coating structure comprising a hardening layer, an alloy layer, and a self-lubricating layer for complex-configured low-temperature steel friction pairs. First, the nanodiamond hardening layer is achieved through supersonic particle bombardment. By incorporating nanodiamond particles into the bombardment particles, the high-speed airflow particles repeatedly impact the low-temperature steel surface, causing severe plastic deformation and generating numerous dislocations. This refines the surface grains of the low-temperature steel, forming a nanostructure, and embeds diamond particles into the surface, thus forming the hardening layer. Second, a nickel-based plating layer is deposited on the low-temperature steel hardening layer using electroplating or chemical plating technology, improving the low-temperature toughness and tribological properties of the friction pair surface, and enhancing the bonding strength and surface integrity of the composite coating. Third, depending on the service conditions of the friction pair, the supersonic particle bombardment and electroplating or chemical plating processes are repeated multiple times to increase the thickness of the composite coating to meet dimensional requirements. Finally, solid lubricants, such as silver powder, copper powder, MoS2, or graphene oxide, are added to the nickel-based plating bath. A self-lubricating composite coating is then formed on the surface of the friction pair using electroplating or electroless plating. This improves the wear reduction caused by boundary lubrication and lean lubrication in the initial friction stage, enhances the self-lubricating performance of the coating, and reduces friction loss. Therefore, after multiple SFPB treatments and electroplating or electroless plating, a diamond-nickel-based multilayer composite coating with a soft-hard bond is formed on the sample surface, which improves both the surface hardness of the friction pair and its friction-reducing and wear-resistant properties.

[0017] The modified layer prepared by the above method has a hardened layer and a self-lubricating layer, exhibiting good bonding performance and high hardness and wear resistance, making it suitable for cryogenic steel friction pairs in polar ships with complex configurations. This method is simple to implement, highly flexible, low in energy consumption, efficient, pollution-free, and easy to industrialize. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of the surface strengthening method for low-temperature steel friction pairs of complex polar ships according to the present invention;

[0019] Figure 2 This is a schematic diagram of the surface strengthening layer of the low-temperature steel friction pair for complex polar ships according to the present invention;

[0020] Figure 3 The friction coefficient test diagram of the low-temperature steel for polar ships and its surface modification layer is shown in the example. Detailed Implementation

[0021] Specific Implementation Method 1: This implementation method is applicable to the surface strengthening method of low-temperature steel friction pairs for complex polar ships and is carried out according to the following steps:

[0022] 1. Grinding and ultrasonic cleaning are performed on the low-temperature steel friction pair material to obtain a clean low-temperature steel friction pair material;

[0023] 2. The nano-diamond particles and spherical hard ceramic particles are mixed at a mass ratio of 1:15-1:30. The powder is then mixed evenly using a ball mill. After mixing, the powder is dried and preheated. The preheated powder is then placed into the cavity of the supersonic particle bombardment device.

[0024] 3. Based on the shape of the friction pair and its service conditions, formulate a nickel-based plating solution using either electroplating or chemical plating processes;

[0025] IV. Using a supersonic particle bombardment device, adjust the gas pressure during the supersonic particle bombardment process to 1.0-1.5MPa, the jet speed to 340-370m / s, and the bombardment angle to 30°-90°, and perform supersonic particle bombardment treatment on the clean surface of the friction pair material to obtain a friction pair material with a nano-hardened reinforcing layer.

[0026] V. Using a nickel-based plating solution, a nickel-based plating layer is prepared on the friction pair material with a nano-hardened reinforcing layer by chemical plating or electroplating processes.

[0027] 6. Repeat steps four and five multiple times to obtain a friction pair material with multiple reinforcement layers;

[0028] 7. Add a lubricating phase to the nickel-based plating solution to obtain a composite plating solution;

[0029] 8. Using chemical plating or electroplating processes and composite plating solutions, a self-lubricating coating is prepared on the surface of friction pair materials with multiple reinforcement layers to complete the surface strengthening of low-temperature steel friction pairs.

[0030] The lubricating phase mentioned in step seven is graphene oxide, nano-sized MoS2, nano-silver, or nano-copper.

[0031] The SFPB nozzle used in step four of this embodiment is equipped with a robotic arm, allowing for a more flexible spray angle.

[0032] In step five of this embodiment, the process for electroplating is: cleaning, electro-cleaning, activation, and electroplating; or the process for chemical plating is: cleaning, activation, and chemical plating.

[0033] This embodiment utilizes supersonic particle bombardment (SFPB) technology to achieve surface nano-sizing and surface alloying by mixing target element powders. By combining surface supersonic particle bombardment treatment with electroplating and electroless plating techniques, a multi-layer nickel-based composite structure consisting of a nano-hardened layer, an alloy layer, and a self-lubricating layer is prepared on the friction pair surface. This improves the hardness, wear resistance, and service stability of the friction pair, extending its service life.

[0034] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the particle size of the spherical hard ceramic microparticles in step two is 100μm-150μm, and the particle size of the nanodiamond particles is 50-200nm.

[0035] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the material of the spherical hard ceramic particles in step 2 is Al2O3 ceramic powder, Si3N4 ceramic powder, or ZrO2 ceramic powder.

[0036] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that in step two, the powder is ball-milled for 1-2 hours.

[0037] Specific Implementation Method 5: This implementation method differs from one of the specific implementation methods 1 to 4 in that the preheating treatment described in step 2 is preheating at 100°C for 10-30 minutes.

[0038] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the main salt in the nickel-based plating solution in step three is NiCl2·6H2O or NiSO4·6H2O.

[0039] This embodiment applies to nickel-based plating solutions used in brush plating processes where the concentration of NiSO4·6H2O is 220–260 g / L, the concentration of ammonium acetate is 35–50 g / L, the concentration of ammonium citrate is 40–60 g / L, the concentration of ammonium oxalate is 0.3–0.6 g / L, and the concentration of ammonia is 100–120 ml / L.

[0040] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the supersonic particle bombardment treatment time in step four is 5-20 minutes.

[0041] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that, in step five, when using the electroplating process, the control voltage is 8-12V, the plating speed is 6-15m / min, and the plating time is 6-12min.

[0042] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that step six repeats steps four and five 3-8 times in sequence.

[0043] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the particle size of the lubricating phase in step 7 is 50-100 nm, and the amount of lubricating phase added is 1%-5% of the molar percentage of the main salt in the nickel-based plating solution.

[0044] Example 1: This example describes a surface strengthening method for low-temperature steel friction pairs in complex polar ships, implemented according to the following steps:

[0045] 1. Select flat WQ960E marine low-temperature steel as the base material, cut the low-temperature steel base material into 15mm×15mm×10mm blocks, grind and ultrasonically clean the base material to remove surface oil and oxides, and obtain clean low-temperature steel friction pair material.

[0046] 2. Nanodiamond particles (50-200nm in diameter) are mixed with spherical hard ceramic particles at a mass ratio of 1:15, wherein the hard ceramic particles are spherical α-Al2O3 ceramic particles of 100μm-150μm. The powder is mixed using a ball mill for 2 hours. After mixing, the powder is dried and preheated. The preheating treatment is performed at 100℃ for 10 minutes. The preheated mixed powder is then placed into the cavity of the supersonic particle bombardment device.

[0047] 3. Based on the shape of the friction pair and the service conditions, and using the electroplating process, a low-temperature steel substrate is connected to the negative electrode of the power supply. A nickel-based plating solution is prepared with the following concentrations: NiSO4·6H2O at 240 g / L, ammonium acetate at 40 g / L, ammonium citrate at 50 g / L, ammonium oxalate at 0.5 g / L, and ammonia (25%) at 110 ml / L.

[0048] IV. Using a supersonic particle bombardment device equipped with a robotic arm that can freely adjust the nozzle angle, a path is planned on the surface of a complex-shaped substrate. Using the supersonic particle bombardment device, the gas pressure during the supersonic particle bombardment process is adjusted to 1.0 MPa, the jet speed to 360 m / s, and the bombardment angle to 90°. The clean friction pair material surface is bombarded with supersonic particles for 5 minutes to obtain a friction pair material with a nano-hardened reinforcing layer.

[0049] V. Using a nickel-based plating solution, an electroplating process was adopted. The electroplating process parameters were: voltage 12V, plating speed 12m / min, and plating time 5min. A nickel-based plating layer was then prepared on the friction pair material with a nano-hardened reinforcing layer.

[0050] 6. Repeat steps 4 and 5 6 times in sequence to obtain a friction pair material with multiple reinforcement layers, including 7 layers of hardened layer and 7 layers of nickel-based plating layer, for a total of 14 layers;

[0051] 7. Add a lubricating phase to the nickel-based plating solution, and add silver powder with a molar ratio of 2% and a diameter of 50 nm to obtain a composite plating solution;

[0052] 8. Using an electroplating process and a composite plating solution, a self-lubricating coating is prepared on the surface of a friction pair material with multiple reinforcement layers. The electroplating process parameters are: voltage 12V, plating speed 12m / min, and plating time 7min, to complete the surface strengthening of the low-temperature steel friction pair.

[0053] The sample of the low-temperature steel surface nano-multilayer modified layer obtained in this embodiment was cut and its tribological properties were tested using an HT-1000 high-temperature friction and wear testing machine. The test preload was 10N, the frequency was 10Hz, the test time was 30min, and the test temperature was 20℃. The friction coefficient of the modified layer was 0.24, which is nearly 15% lower than the friction coefficient of 0.27 measured under the same conditions for WQ960E steel plate. The wear weight loss was 0.017mg, which is more than 20% lower than the weight loss of 0.022mg for WQ960E steel plate.

[0054] In summary, this invention provides a surface strengthening method for low-temperature steel friction pairs in complex polar vessels, belonging to the fields of machining and surface modification. Its aim is to provide a comprehensive, thorough surface strengthening method for these friction pairs, addressing the issues of uneven surface strengthening in complex structures and the decline in frictional performance caused by low-temperature environments. This invention is based on supersonic particle bombardment technology, involving electroplating, electroless plating, and 3-8 rounds of supersonic particle bombardment. This invention prepares a strengthened coating with a combination of a hardened layer and a lubricating film on the surface of low-temperature steel in complex polar vessels, exhibiting excellent forming quality and good wear resistance. The operation process is simple, pollution-free, and easily industrialized.

Claims

1. A surface strengthening method for low-temperature steel friction pairs suitable for complex polar ships, characterized in that... This surface strengthening method is implemented through the following steps:

1. Grinding and ultrasonic cleaning are performed on the low-temperature steel friction pair material to obtain a clean low-temperature steel friction pair material; 2. The nano-diamond particles and spherical hard ceramic particles are mixed at a mass ratio of 1:15-1:

30. The powder is then mixed evenly using a ball mill. After mixing, the powder is dried and preheated. The preheated powder is then placed into the cavity of the supersonic particle bombardment device.

3. Based on the shape of the friction pair and its service conditions, formulate a nickel-based plating solution using either electroplating or chemical plating processes; IV. Using a supersonic particle bombardment device, adjust the gas pressure during the supersonic particle bombardment process to 1.0-1.5MPa, the jet speed to 340-370m / s, and the bombardment angle to 30°-90°, and perform supersonic particle bombardment treatment on the clean surface of the friction pair material to obtain a friction pair material with a nano-hardened reinforcing layer. V. Using a nickel-based plating solution, a nickel-based plating layer is prepared on the friction pair material with a nano-hardened reinforcing layer by chemical plating or electroplating processes.

6. Repeat steps four and five multiple times to obtain a friction pair material with multiple reinforcement layers; 7. Add a lubricating phase to the nickel-based plating solution to obtain a composite plating solution; 8. Using chemical plating or electroplating processes and composite plating solutions, a self-lubricating coating is prepared on the surface of friction pair materials with multiple reinforcement layers to complete the surface strengthening of low-temperature steel friction pairs. The lubricating phase mentioned in step seven is graphene oxide, nano-sized MoS2, nano-silver, or nano-copper.

2. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... The spherical hard ceramic microparticles mentioned in step two have a particle size of 100μm-150μm, and the nanodiamond particles have a particle size of 50-200nm.

3. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step two, the spherical hard ceramic particles are made of Al2O3 ceramic powder, Si3N4 ceramic powder, or ZrO2 ceramic powder.

4. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step two, the powder is ball-milled for 1-2 hours.

5. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... The preheating process described in step two involves preheating at 100°C for 10-30 minutes.

6. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step three, the main salt in the nickel-based plating solution is either NiCl2·6H2O or NiSO4·6H2O.

7. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... The supersonic particle bombardment treatment in step four takes 5-20 minutes.

8. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step five, when using the electroplating process, control the voltage to 8-12V, the plating speed to 6-15m / min, and the plating time to 6-12min.

9. The surface strengthening method for low-temperature steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step six, repeat steps four and five 3-8 times in sequence.

10. The surface strengthening method for cryogenic steel friction pairs of complex-configured polar ships according to claim 1, characterized in that... In step seven, the particle size of the lubricating phase is 50-100 nm, and the amount of lubricating phase added is 1%-5% of the molar percentage of the main salt in the nickel-based plating solution.

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