Vibrating rotating multiphase jet flow assisted ultra-high-speed laser surface smoothness strengthening method suitable for complex curved surface in wide temperature range

Abstract

The invention discloses a wide-temperature-range vibration rotating multi-phase jet assisted ultra-high-speed laser surface smoothness strengthening method suitable for a complex curved surface, and aims to solve the problems that an undercarriage shaft neck faces a corrosion rust layer and corrosion damage when serving in complex and changeable environments such as high speed, high temperature and high salt mist, and the smooth surface is the complex curved surface. The smoothness strengthening method comprises the following steps of: 1, impacting a journal type workpiece through abrasive gas jet to perform jet cleaning; 2, a workpiece is fixed to an ultra-high-speed laser workbench; 3, constructing a shaft neck 3D curved surface model; 4, performing laser bright and clean treatment; 5, repeating the laser bright and clean treatment in the step 4 for multiple times; 6, performing laser nitriding treatment for multiple times in a nitrogen atmosphere; seventhly, cleaning liquid is sprayed out through a nozzle to impact the journal; and 8, ultrasonic cleaning and drying. According to the novel surface smoothness strengthening process for the ultra-high-speed laser assisted by the vibration rotating multiphase jet flow in the wide temperature range, the shaft neck surface structure can be refined, crack growth is inhibited, and the service life of a shaft neck component is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal surface treatment, and in particular relates to a vibrating and rotating multiphase jet-assisted ultra-high-speed laser surface finishing and strengthening process in a wide temperature range. Background Art

[0002] With the rapid development of aerospace technology, low cost has become one of the main challenges facing aerospace parts, and the reuse of parts is an important measure to reduce costs. Many precision parts have high manufacturing costs, long production cycles, and are difficult to forge, such as landing gear journals and engine blades; when they fail, they are prone to loss of a lot of manpower and material resources. As one of the key systems for horizontal recovery of space vehicles, the landing gear system is the premise and basis for ensuring the reusability of the vehicle. During the retraction and extension of the landing gear, the entire landing gear uses the journal as the rotation axis to achieve the retraction and extension action. In the extrusion and friction under large loads, the working surface of the journal often suffers from scratches, wear and other faults, and the damaged objects are mixed in the gap to cause cumulative damage, which aggravates the damage. In a humid and acidic operating environment, it is more prone to corrosion, causing the failure of the landing gear journal, resulting in damage to the aircraft and even flight accidents. Traditional cleaning processes only meet the requirements for smooth surface of the journal, but the journal after corrosion damage cannot be put back into use due to its low strength and reduced service capacity. Therefore, it is urgent to develop a new type of polishing process to polish and repair the strengthened landing gear journal, so as to achieve the environmental protection measures based on the reuse of the landing gear journal and the subsequent surface coating of protective coating.

[0003] Ultra-high-speed laser finishing refers to a technical process in which laser irradiates the finishing object and removes the contaminants from the surface of the substrate through processes such as thermal vibration and ablation. Compared with traditional finishing processes, laser finishing is a non-contact cleaning process. For precision workpieces and fine parts, such as the difficult-to-process areas of the landing gear journal, it can be fully cleaned without damage, and has the advantages of high efficiency, environmental protection, and energy saving. During the ultra-high-speed laser finishing process, the irradiation of high-energy beams will clean the corrosive rust layer on the surface of the material and repair corrosion damage such as pores, furrows, and cracks; significant temperature gradients and component overcooling will enhance the corrosion resistance and wear resistance of the landing gear journal. In different temperature fields, the ultra-high-speed laser has different finishing methods. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates; at high laser flux, the material is usually converted into plasma. For different materials and different contaminants, ultra-high-speed laser finishing can use corresponding laser fluxes in a wide temperature range, and has a wide range of applicability.

[0004] Multiphase jet is a multiphase fluid in which two or more different phases or components coexist and have a clear interface. The liquid phase is introduced into the abrasive gas jet to impact the rust layer of the landing gear journal to remove it from the surface. The multiphase jet process is coupled with vibration and rotation to release residual impact stress and enhance the finishing ability. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of corrosion rust layer and corrosion damage faced by the landing gear journal when serving in complex and changeable environments such as high speed, high temperature and high salt fog, as well as the problem of complex curved surfaces on the smooth surface, and to provide a method for ultra-high-speed laser surface finishing strengthening assisted by a vibrating rotating multiphase jet in a wide temperature range.

[0006] The present invention is applicable to the ultra-high-speed laser surface finishing strengthening method for complex curved surfaces in a wide temperature range assisted by a vibrating rotating multiphase jet, and is implemented by the following steps:

[0007] 1. Fix the journal workpiece on a vibrating rotary table, then mix abrasive, water and activator to obtain liquid slurry. The vibrating rotary table drives the journal to vibrate and rotate. A multiphase jet device is used to spray liquid slurry through a nozzle to form an abrasive gas jet to impact the journal workpiece, and obtain a jet-cleaned journal.

[0008] 2. Fix the jet-cleaned journal on the ultra-high-speed laser workbench and adjust the distance from the laser gun head to the journal;

[0009] 3. Construct a 3D surface model of the journal according to the size of the journal. Import the 3D surface model of the journal into the laser robot system to generate a 3D surface laser path, so that the laser gun head is perpendicular to the section of the journal surface.

[0010] 4. Laser finishing: In a protective gas atmosphere, first control the laser power to 80-90W, the laser repetition frequency to 90kHz, and the laser scanning speed to 7000-9000mm / s to perform high-power and high-speed scanning laser finishing on the journal. Then control the laser power to 50-53W, the laser repetition frequency to 80kHz, and the laser scanning speed to 4000-6000mm / s to perform low-power and low-speed scanning laser finishing. After air cooling (rapid cooling and recrystallization), the journal after laser finishing is obtained.

[0011] 5. Repeat the laser polishing process in step 4 several times;

[0012] 6. In a nitrogen atmosphere, the laser power is controlled to be 80-90W, the laser repetition frequency is 90kHz, and the laser scanning speed is 7000-9000mm / s to perform laser nitriding treatment on the journal for multiple times to obtain a nitrided journal;

[0013] 7. Fix the nitrided journal on a vibrating rotary workbench, which drives the journal to vibrate and rotate, and use a multiphase jet device to spray a cleaning liquid through a nozzle to impact the journal, thereby obtaining a journal with a ceramic layer-passivation layer gradient protective layer;

[0014] 8. Ultrasonic cleaning is performed on the journal with the ceramic layer-passivation layer gradient protective layer, and the journal after enhanced cleaning is obtained after drying, thereby completing the ultra-high-speed laser surface finishing and strengthening method assisted by the vibration rotating multiphase jet in a wide temperature range.

[0015] Compared with the existing process technology, the vibration rotating multiphase jet assisted ultra-high speed laser surface finishing strengthening method of the present invention has the following beneficial effects:

[0016] After the polishing and strengthening treatment, the present invention removes the rust layer of the journal corrosion, and the polishing effect is obvious. The composite polishing process based on ultra-high-speed laser polishing is green and environmentally friendly, and has a wide range of applicability. The new ultra-high-speed laser surface polishing and strengthening process assisted by a vibrating rotating multiphase jet in a wide temperature range can refine the surface structure of the journal, inhibit crack growth, and extend the service life of the journal components; the mechanical properties of the journal, such as fatigue resistance and wear resistance, can be improved; a gradient protective layer structure of a ceramic layer-passivation layer covering the surface of the journal is realized, and the corrosion resistance of the journal is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A 3D curved surface model diagram of a journal constructed in the embodiment;

[0018] Figure 2 The process flow chart of the present invention is applicable to the ultra-high-speed laser surface finishing and strengthening method of the present invention for complex curved surfaces in a wide temperature range assisted by a vibrating rotating multiphase jet;

[0019] Figure 3 The electron microscope images of the journal workpiece surface before and after the smooth and strengthening treatment in the embodiment are compared. The left image is before the smooth and strengthening treatment, and the right image is after the smooth and strengthening treatment. DETAILED DESCRIPTION

[0020] Specific implementation method 1: This implementation method is applicable to the ultra-high-speed laser surface finishing strengthening method assisted by a vibrating rotating multiphase jet in a wide temperature range on complex curved surfaces, and is implemented in the following steps:

[0021] 1. Fix the journal workpiece on a vibrating rotary table, then mix abrasive, water and activator to obtain liquid slurry. The vibrating rotary table drives the journal to vibrate and rotate. A multiphase jet device is used to spray liquid slurry through a nozzle to form an abrasive gas jet to impact the journal workpiece, and obtain a jet-cleaned journal.

[0022] 2. Fix the jet-cleaned journal on the ultra-high-speed laser workbench and adjust the distance from the laser gun head to the journal;

[0023] 3. Construct a 3D surface model of the journal according to the size of the journal. Import the 3D surface model of the journal into the laser robot system to generate a 3D surface laser path, so that the laser gun head is perpendicular to the section of the journal surface.

[0024] 4. Laser finishing: In a protective gas atmosphere, first control the laser power to 80-90W, the laser repetition frequency to 90kHz, and the laser scanning speed to 7000-9000mm / s to perform high-power and high-speed scanning laser finishing on the journal. Then control the laser power to 50-53W, the laser repetition frequency to 80kHz, and the laser scanning speed to 4000-6000mm / s to perform low-power and low-speed scanning laser finishing. After air cooling, the journal after laser finishing is obtained.

[0025] 5. Repeat the laser polishing process in step 4 several times;

[0026] 6. In a nitrogen atmosphere, the laser power is controlled to be 80-90W, the laser repetition frequency is 90kHz, and the laser scanning speed is 7000-9000mm / s to perform laser nitriding treatment on the journal for multiple times to obtain a nitrided journal;

[0027] 7. Fix the nitrided journal on a vibrating rotary workbench, which drives the journal to vibrate and rotate, and use a multiphase jet device to spray a cleaning liquid through a nozzle to impact the journal, thereby obtaining a journal with a ceramic layer-passivation layer gradient protective layer;

[0028] 8. Ultrasonic cleaning is performed on the journal with the ceramic layer-passivation layer gradient protective layer, and the journal after enhanced cleaning is obtained after drying, thereby completing the ultra-high-speed laser surface finishing and strengthening method assisted by the vibration rotating multiphase jet in a wide temperature range.

[0029] This embodiment is based on 3D model construction and adopts vibrating rotating multiphase jet assisted ultra-high-speed laser to clean the corrosion rust layer of the landing gear journal in a wide temperature range, repair the surface corrosion damage such as pores, furrows, cracks, etc. generated during its service, and enhance the corrosion resistance and wear resistance of the landing gear journal; build a gradient protective layer of ceramic layer-passivation layer on the surface of the landing gear journal to further extend its service life after recycling.

[0030] This embodiment combines ultra-high-speed laser cleaning with multi-phase jet to achieve composite cleaning, thereby reducing costs and improving cleaning efficiency.

[0031] Specific implementation method 2: The difference between this implementation method and specific implementation method 1 is that the mass concentration of the abrasive in the liquid slurry in step 1 is 5% to 8%, and the average particle size of the abrasive is 1.0 μm.

[0032] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that in step one, the vibrating rotary worktable drives the journal to vibrate and rotate, and the vibration frequency is controlled to be 25-35 Hz and the rotation speed is 500-1500 r / min.

[0033] Specific embodiment 4: This embodiment is different from any one of specific embodiments 1 to 3 in that the injection pressure of the abrasive gas jet in step 1 is controlled to be 2 to 2.5 MPa.

[0034] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that the protective gas described in step 4 is argon gas.

[0035] Specific implementation method six: The difference between this implementation method and any one of specific implementation methods one to five is that in step four, the laser power is first controlled to 80-90W, the laser repetition frequency is 90kHz, and the laser scanning speed is 8000mm / s to perform high-power and high-speed scanning laser polishing treatment on the journal, and then the laser power is controlled to 50-53W, the laser repetition frequency is 80kHz, and the laser scanning speed is 5000mm / s to perform low-power and low-speed scanning laser polishing treatment.

[0036] Specific implementation method 7: The difference between this implementation method and specific implementation methods 1 to 6 is that in step 5, the laser polishing process is repeated 2 to 3 times.

[0037] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that in step six, laser nitriding treatment of the journal is performed under nitrogen atmosphere by controlling the laser power to 80-90 W, the laser repetition frequency to 90 kHz, and the laser scanning speed to 8000 mm / s.

[0038] Specific embodiment 9: The difference between this embodiment and specific embodiment 8 is that in step 6, the laser nitridation treatment is performed 1 to 3 times.

[0039] Specific implementation method 10: The difference between this implementation method and any one of specific implementation methods 1 to 9 is that in step 7, the spray pressure of the spray cleaning liquid is controlled to be 2 to 2.5 MPa.

[0040] Embodiment: This embodiment is applicable to the method for ultra-high-speed laser surface finishing and strengthening assisted by vibrating rotating multiphase jet in a wide temperature range for complex curved surfaces, and is implemented according to the following steps:

[0041] 1. Fix the journal on a vibrating rotary table, then mix the abrasive, water and activator (sodium dodecylbenzene sulfonate) to obtain a liquid slurry, wherein the mass concentration of the abrasive in the liquid slurry is 6%, and the average particle size of the abrasive is 1.0 μm (i.e., the abrasive particle size is 10000 mesh). The vibrating rotary table drives the journal to vibrate and rotate, and the vibration frequency is controlled to be 30 Hz, and the rotation speed is 1000 r / min. A multiphase jet device is used to use a high-pressure gas jet to carry the liquid slurry to impact the journal, and the jet pressure is controlled to be 2 MPa, the target distance is 10 mm, and the impact angle is 45° to obtain the journal after jet cleaning;

[0042] 2. Fix the journal after jet cleaning on the ultra-high-speed laser workbench, move the laser gun head a short distance to the outer end of the journal, ensure that the laser power is stable when the laser scans the journal workpiece, and adjust the distance from the laser gun head to the journal to 8 cm to ensure the uniformity of the ultra-high-speed laser beam;

[0043] 3. Construct a 3D surface model of the journal according to the size of the journal. Import the 3D surface model of the journal into the laser robot system to generate a 3D surface laser path, so that the laser gun head is perpendicular to the section of the journal surface.

[0044] 4. Laser finishing: In an argon atmosphere, first control the laser power to 90W, the laser repetition frequency to 90kHz, and the laser scanning speed to 8000mm / s to perform high-power and high-speed scanning laser finishing on the journal. The high heat accumulation of the heat source is used to quickly heat the contamination layer and the corrosion layer, resulting in a chemical reaction, so that the contamination layer, impurity particles and corrosion layer are separated from the journal surface.

[0045] Then the laser power is controlled to 50W, the laser repetition frequency is 80kHz, and the laser scanning speed is 5000mm / s to perform low-power and low-speed scanning laser finishing treatment to release residual stress and reduce the surface roughness of the journal. The air cooling treatment utilizes rapid cooling (cooling) recrystallization to improve the hardness, wear resistance and corrosion resistance of the journal to obtain the journal after laser finishing treatment;

[0046] 5. Repeat the laser finishing process in step 4 twice, and the corrosion damage on the journal surface is basically smooth and complete;

[0047] 6. Under nitrogen atmosphere, laser power was controlled to be 90W, laser repetition frequency was 90kHz, and laser scanning speed was 8000mm / s to perform laser nitriding treatment on the journal twice, and a ceramic layer was generated in situ to achieve the effect of refining grains, improving mechanical properties and corrosion resistance of the journal, and obtaining a nitrided journal;

[0048] 7. Fix the nitrided journal on a vibrating rotary worktable, which drives the journal to vibrate and rotate, then mix the corrosion inhibitor (phenolic resin), passivator (citric acid) and water to obtain a cleaning liquid, and use a multiphase jet device to use a high-pressure gas jet to carry the cleaning liquid to impact the journal, remove residual stress, and form a passivation film on the surface of the journal to obtain a journal with a ceramic layer-passivation layer gradient protective layer;

[0049] 8. Ultrasonic cleaning is performed on the journal with the ceramic layer-passivation layer gradient protective layer, and the journal after enhanced cleaning is obtained after drying, thereby completing the ultra-high-speed laser surface finishing and strengthening method assisted by the vibration rotating multiphase jet in a wide temperature range.

[0050] According to the corrosion situation, the finish grade is divided into A, B, C and D. The standards are as follows:

[0051] Finish grade standard

[0052] Finish Grade describe Level A The surface is smooth and almost free of corrosion and rust Class B The surface is basically smooth, but there are a few rust spots C-Class There is a more obvious rust layer on the surface, but the distribution is less D-Class The surface is relatively rough and covered with a large amount of corrosive rust

[0053] The finish rating of the journal obtained in this embodiment is A. Figure 3 It can be seen from the electron microscope image that after the polishing and strengthening treatment of this embodiment, the surface structure of the journal workpiece is refined and there is no rust spot on the workpiece surface.

[0054] The present invention provides a surface finishing process for the complex curved surface of the landing gear journal, a new composite surface finishing and strengthening process using a vibrating rotating multiphase jet in a wide temperature range to assist ultra-high-speed laser finishing, with obvious finishing effect, environmental protection and no pollution, which not only solves the problems brought by traditional processes and realizes the ceramic layer-passivation layer gradient protection, but also further improves the original corrosion resistance and wear resistance of the component, prolongs its service life, and realizes comprehensive finishing and reuse environmental protection measures.

Claims

1. A method for ultra-high-speed laser surface finishing and strengthening in a wide temperature range by vibrating and rotating multiphase jet assisted by complex curved surfaces, characterized in that The vibrating rotating multiphase jet assisted ultra-high speed laser surface finishing strengthening method is implemented according to the following steps:

1. Fix the journal workpiece on a vibrating rotary table, then mix abrasive, water and activator to obtain liquid slurry. The vibrating rotary table drives the journal to vibrate and rotate. A multiphase jet device is used to spray liquid slurry through a nozzle to form an abrasive gas jet to impact the journal workpiece, and obtain a jet-cleaned journal.

2. Fix the jet-cleaned journal on the ultra-high-speed laser workbench and adjust the distance from the laser gun head to the journal; 3. Construct a 3D surface model of the journal according to the size of the journal. Import the 3D surface model of the journal into the laser robot system to generate a 3D surface laser path, so that the laser gun head is perpendicular to the section of the journal surface.

4. Laser finishing: In a protective gas atmosphere, first control the laser power to 80-90W, the laser repetition frequency to 90kHz, and the laser scanning speed to 7000-9000mm / s to perform high-power and high-speed scanning laser finishing on the journal. Then control the laser power to 50-53W, the laser repetition frequency to 80kHz, and the laser scanning speed to 4000-6000mm / s to perform low-power and low-speed scanning laser finishing. After air cooling, the journal after laser finishing is obtained.

5. Repeat the laser polishing process in step 4 several times; 6. In a nitrogen atmosphere, the laser power is controlled to be 80-90W, the laser repetition frequency is 90kHz, and the laser scanning speed is 7000-9000mm / s to perform laser nitriding treatment on the journal for multiple times to obtain a nitrided journal; 7. Fix the nitrided journal on a vibrating rotary workbench, which drives the journal to vibrate and rotate, and use a multiphase jet device to spray a cleaning liquid through a nozzle to impact the journal, thereby obtaining a journal with a ceramic layer-passivation layer gradient protective layer; 8. Ultrasonic cleaning is performed on the journal with the ceramic layer-passivation layer gradient protective layer, and the journal after enhanced cleaning is obtained after drying, thereby completing the ultra-high-speed laser surface finishing enhancement method assisted by the vibration rotating multiphase jet in a wide temperature range.

2. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that The mass concentration of the abrasive in the liquid slurry in step 1 is 5% to 8%, and the average particle size of the abrasive is 1.0 μm.

3. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step 1, the vibrating rotary worktable drives the journal to vibrate and rotate, and the vibration frequency is controlled to be 25-35 Hz and the rotation speed is 500-1500 r / min.

4. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step 1, the injection pressure of the abrasive gas jet is controlled to be 2-2.5 MPa.

5. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that The protective gas described in step 4 is argon.

6. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step 4, first control the laser power to 80-90W, the laser repetition frequency to 90kHz, and the laser scanning speed to 8000mm / s to perform high-power and high-speed scanning laser polishing on the journal, and then control the laser power to 50-53W, the laser repetition frequency to 80kHz, and the laser scanning speed to 5000mm / s to perform low-power and low-speed scanning laser polishing.

7. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step 5, the laser polishing process is repeated 2 to 3 times.

8. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step six, in a nitrogen atmosphere, the laser power is controlled to be 80-90 W, the laser repetition frequency is 90 kHz, and the laser scanning speed is 8000 mm / s to perform laser nitriding treatment on the journal.

9. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 8, characterized in that In step six, laser nitridation is performed 1 to 3 times.

10. The method for surface finishing and strengthening of complex curved surfaces by ultra-high-speed laser assisted by a vibrating rotating multiphase jet in a wide temperature range according to claim 1, characterized in that In step seven, the spray pressure of the spray cleaning liquid is controlled to be 2-2.5 MPa.

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