Titanium alloy laser polishing system and method based on chemical assistance

Abstract

The invention relates to the technical field of titanium alloy laser polishing, in particular to a titanium alloy laser polishing system and method based on chemical assistance. The titanium alloy laser polishing system comprises an inert gas supply and recovery device, a polishing box, a containing box, a laser device, an electric lifting platform, an electric pump and a transparent sealing cover plate. The containing box is used for containing neutral chemical liquid, the inert gas supply and recovery device and the containing box are communicated with the polishing box, the laser is arranged above the polishing box, and the electric lifting table is installed in the polishing box and used for containing a titanium alloy sample plate to be polished. The electric pump is installed in the containing box and used for conveying the neutral chemical liquid to the polishing box. The transparent sealing cover plate is arranged on the polishing box in a covering mode and used for enabling the polishing process to be in an oxygen-free environment, oxidation reaction of workpieces is avoided, and the inert gas supply and recovery device is used for introducing inert gas to the position above the liquid level, containing the neutral chemical liquid, of the polishing box.

Description

Technical Field

[0001] The present invention relates to the technical field of laser polishing of titanium alloys, in particular to a laser polishing titanium alloy system and method based on chemical assistance. Background Art

[0002] Titanium alloys have a series of excellent physical and chemical properties such as low density, good corrosion resistance, and high specific strength, and thus are widely used in various fields such as aerospace, medical, and manufacturing. With the in-depth application of titanium alloys in the industry, the requirements for the surface finish of titanium alloys are constantly increasing. Laser polishing is a new type of surface treatment method, which has the advantages of environmental protection and non-contact, and is one of the important processing methods to obtain high surface finish of materials. When high-energy laser irradiates the material surface, it will cause the surface material to melt, forming a liquid molten pool. The liquid material after heating and melting will be subjected to a multi-directional force composed of surface tension and gravity. At the microscopic level, the workpiece surface is in a "concave-convex" state. Under the action of the multi-directional force, the liquid material will flow and redistribute in the molten pool, and the convex surface of the material will leave the initial position and flow to the workpiece surface with a lower level. When the high-energy laser leaves the processed area, the surface liquid molten pool will quickly cool and shrink and solidify quickly. At this time, the material of the convex part of the surface wave peak will flow to the wave valley, reducing the height difference, that is, "filling the valleys with peaks", thereby obtaining a high-quality smooth surface. However, the current titanium alloy laser polishing technology requires a strict airtight device and is carried out in an atmosphere of protective gas. Otherwise, at high temperatures, titanium will react with oxygen and nitrogen, affecting the surface finish of the titanium alloy sample. The polishing liquid used in conventional chemical polishing contains strong acids and alkalis, which will corrode the polishing device and cannot be used for a long time.

[0003] To solve the above problems, the present invention combines laser polishing and chemical polishing, configures a neutral chemical solution, and designs a laser polishing device that is more flexible and has strong automation applicability. The titanium alloy sample is placed in the chemical solution, equipped with a gas-liquid circulation system. The device is simple, has high stability, and is suitable for factory-style automated production. Only by regularly replenishing the chemical solution and inert gas can automatic polishing be achieved. It has a high degree of automation and the characteristics of environmental protection. Summary of the Invention

[0004] The embodiment of the present invention provides a laser polishing titanium alloy system and method based on chemical assistance, which configures a neutral chemical solution and designs a laser polishing device that is more flexible and has strong automation applicability. The titanium alloy sample is placed in the chemical solution, equipped with a gas-liquid circulation system. The device is simple, has high stability, and is suitable for factory-style automated production. Only by regularly replenishing the chemical solution and inert gas can automatic polishing be achieved. It has a high degree of automation and the characteristics of environmental protection.

[0005] The present invention discloses a chemical-assisted laser polishing system for titanium alloy, which includes an inert gas supply and recovery device, a polishing box, a storage box, a laser, an electric lifting table, an electric pump, and a transparent sealing cover plate;

[0006] The inert gas supply and recovery device and the storage box are respectively communicated with the polishing box. The laser is arranged above the polishing box. The electric lifting table is installed in the polishing box and is used to place the titanium alloy sample to be polished. The electric pump is installed in the storage box and is used to transport the neutral chemical liquid to the polishing box. The transparent sealing cover plate is covered on the polishing box to make the polishing process in an oxygen-free environment to avoid the oxidation reaction of the workpiece. The inert gas supply and recovery device is used to introduce inert gas above the liquid surface of the polishing box filled with the neutral chemical liquid.

[0007] Optionally, a jet nozzle and a suction nozzle are arranged at the top of the inner side wall of the polishing box. The inert gas supply and recovery device is communicated with the jet nozzle through a gas supply pipeline, and the inert gas supply and recovery device is communicated with the suction nozzle through a gas return pipeline.

[0008] Optionally, the electric lifting table can be lifted to the same height as the jet nozzle.

[0009] The present invention also discloses a chemical-assisted laser polishing method for titanium alloy, which is applied to the laser polishing system for titanium alloy as described above, and includes the steps:

[0010] Add sodium phosphate, potassium chloride, and calcium chloride to deionized water, stir and dissolve to obtain a neutral chemical liquid, and heat it to 35 - 40 °C for insulation; wherein, the concentration of sodium phosphate in the neutral chemical liquid is 10 - 15 g / mL, the concentration of potassium chloride is 4 - 6 g / mL, and the concentration of calcium chloride is 4 - 6 g / mL;

[0011] Immerse the titanium alloy sample to be polished in the polishing box filled with flowing neutral chemical liquid;

[0012] Flow and fill inert gas in the polishing box;

[0013] Laser polish the titanium alloy sample to be polished.

[0014] Optionally, the process parameters of laser polishing are: laser power 300 - 500 W, scanning speed 400 - 800 mm / s, line spacing 0.02 - 0.06 mm, defocus amount +2 - +10 mm, spot size 10 - 15 mm.

[0015] Optionally, after the titanium alloy sample to be polished is immersed in the polishing box filled with the neutral chemical liquid, the distance between the surface of the titanium alloy sample to be polished and the liquid surface of the neutral chemical liquid is 20 - 40 mm.

[0016] Optionally, an inert gas flows into the polishing chamber, and the intake and outlet volumes of the inert gas are 300-500 mL / min.

[0017] Optionally, a neutral chemical liquid flows into the polishing chamber, and the intake and outlet volumes of the neutral chemical liquid are 100-200 mL / min.

[0018] Optionally, before immersing the titanium alloy sample to be polished in the polishing chamber filled with the neutral chemical liquid, the following steps are further included:

[0019] After surface cleaning with 70% alcohol, air-dry the titanium alloy sample to be polished.

[0020] Optionally, the titanium alloy sample to be polished is Ti-6Al-4V titanium alloy.

[0021] Compared with the prior art, the beneficial effects of the laser polishing method for titanium alloy based on chemical assistance provided by the embodiments of the present invention are as follows: On the basis of using a neutral chemical liquid to hermetically isolate air, the present invention also fills an inert gas into the polishing chamber to cooperate with the neutral chemical liquid to jointly improve the polishing quality of the titanium alloy. Specifically, the stable chemical environment formed by sodium phosphate, potassium chloride, and calcium chloride in the neutral chemical liquid, and the inert gas (such as argon) is introduced into the neutral chemical liquid during the polishing process, which can form a protective gas layer to prevent air from mixing into the neutral chemical liquid. At the same time, the flowing neutral chemical liquid and inert gas can both carry away a large amount of heat and bubbles generated during the laser process in real time, realizing a comprehensive airtight seal for the titanium alloy. Brief Description of the Drawings

[0022] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings and embodiments. In the drawings:

[0023] Figure 1 is a schematic diagram of the laser polishing system for titanium alloy according to the embodiment of the present invention.

[0024] The reference numerals in the drawings are as follows:

[0025] 1. Inert gas supply and recovery device; 2. Polishing chamber; 3. Containment box; 4. Laser; 5. Electric lifting platform; 6. Electric pump; 7. Transparent sealing cover; 8. Jet nozzle; 9. Suction nozzle; 11. Gas supply pipe; 12. Gas return pipe; 13. Liquid inlet pipe; 14. Liquid outlet pipe. Detailed Embodiments

[0026] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the drawings, the preferred embodiments of the present invention will be described in detail.

[0027] The embodiments of the present invention provide a laser polishing system for titanium alloy based on chemical assistance, asFigure 1 As shown in the figure, it includes an inert gas supply and recovery device 1, a polishing box 2, a storage box 3, a laser 4, an electric lifting table 5, an electric pump 6, and a transparent sealing cover plate 7.

[0028] The storage box 3 is used to contain a neutral chemical liquid. The inert gas supply and recovery device 1 and the storage box 3 are respectively communicated with the polishing box 2. The laser 4 is arranged above the polishing box 2. The electric lifting table 5 is installed in the polishing box 2 and is used to place the titanium alloy sample to be polished. The electric pump 6 is installed in the storage box 3 and is used to transport the neutral chemical liquid to the polishing box 2. The transparent sealing cover plate 7 is covered on the polishing box 2 to make the polishing process in an oxygen-free environment to avoid the oxidation reaction of the workpiece. The inert gas supply and recovery device 1 is used to introduce inert gas above the liquid surface after the polishing box 2 is filled with the neutral chemical liquid.

[0029] For the chemical-assisted laser polishing titanium alloy system of the present invention, the storage box 3 and the polishing box 2 transport the neutral chemical liquid to the polishing box 2 through the electric pump 6. The titanium alloy sample to be polished is placed on the electric lifting table 5 and immersed in the neutral chemical liquid. In the polishing box 2, inert gas is filled through the inert gas supply and recovery device 1 for polishing. The neutral chemical liquid plays a role in airtight isolation of air, eliminating the cumbersome traditional airtight device. The neutral chemical liquid is easy to configure, has a high recycling rate, and the surface of the polished titanium alloy will not appear micro-pits and is smoother. At the same time, the overall laser polishing titanium alloy system realizes automation through the electric lifting table 5, the electric pump 6, etc., and has a high degree of automation.

[0030] Based on using the neutral chemical liquid to airtight isolate air, the present invention also fills inert gas into the polishing box 2 to jointly improve the polishing quality of the titanium alloy with the neutral chemical liquid. Specifically, the stable chemical environment formed by sodium phosphate, potassium chloride, and calcium chloride in the neutral chemical liquid, and the inert gas (such as argon) is introduced into the neutral chemical liquid during the polishing process, which can form a protective gas layer to avoid air from mixing into the neutral chemical liquid. At the same time, the flowing neutral chemical liquid and inert gas can both take away a large amount of heat and bubbles generated during the laser process in real time, realizing the full airtight seal of the titanium alloy.

[0031] Especially, the present invention further combines flowing inert gas on the basis of flowing neutral chemical liquid, which can take away bubbles in all directions and quickly, prevent the appearance of cavitation pits on the surface of the titanium alloy, and at the same time can take away heat in all directions and quickly, making the polished surface smoother and comprehensively improving the polishing quality of the titanium alloy.

[0032] Specifically, a transparent sealing cover plate 7 covers the polishing box 2 to seal the polishing box 2 and prevent the escape of inert gas. The inert gas supply and recovery device 1 has an inert gas supply function and an inert gas recovery function. For example, the inert gas supply can be achieved through an inert gas supply gas cylinder, and the inert gas recovery can be achieved through an inert gas recovery bottle. Conventional techniques can be used and will not be specifically elaborated here. The electric lifting table 5 has an electric control lifting function, and it can be automatically lifted by using a cylinder or a motor with high airtightness. Conventional techniques can be used and will not be specifically elaborated here. The electric pump 6 transports the neutral chemical liquid in the storage box 3 to the polishing box 2 through the liquid inlet pipe 13. After polishing is completed or when the neutral chemical liquid needs to be replaced, the neutral chemical liquid flows back to the storage box 3 through the liquid outlet pipe 14. The liquid outlet pipe 14 can be connected to the lower part or the bottom of the polishing box 2 to facilitate the reflux of the neutral chemical liquid. Of course, it can also be directly transported and refluxed through another electric pump, which will not be specifically elaborated here. Control valves can be set or not set on the liquid inlet pipe 13 and the liquid outlet pipe 14 as needed, which will not be specifically elaborated here.

[0033] The neutral chemical liquid is obtained by adding sodium phosphate, potassium chloride, and calcium chloride to deionized water and stirring to dissolve. The specific content of each component and the preparation process are as described in the following laser polishing method for titanium alloy based on chemical assistance, which will not be specifically elaborated here.

[0034] The titanium alloy sample to be polished is immersed in the neutral chemical liquid prepared from sodium phosphate, potassium chloride, and calcium chloride. At the same time, an inert gas is filled in the polishing box 2 for polishing. The neutral chemical liquid plays a role of airtight isolation from the air, eliminating the cumbersome traditional airtightness device. The neutral chemical liquid is easy to prepare, has a high recycling rate, and the surface of the polished titanium alloy will not have micro-pits and is smoother.

[0035] Specifically, a jet nozzle 8 and a suction nozzle 9 are provided at the top of the inner side wall of the polishing box 2. The inert gas supply and recovery device 1 is connected to the jet nozzle 8 through a gas supply pipe 11, and the inert gas supply and recovery device 1 is connected to the suction nozzle 9 through a gas return pipe 12. The jet nozzle 8 injects inert gas above the liquid level after the polishing box 2 is filled with the neutral chemical liquid, and the suction nozzle 9 recovers the inert gas. Control valves can be set or not set on the gas supply pipe 11 and the gas return pipe as needed, which will not be specifically elaborated here.

[0036] Specifically, the electric lifting table 5 can be lifted to the same height as the jet nozzle 8. After laser polishing is completed, the electric lifting table 5 rises and comes out of the neutral chemical liquid and rises to the same height as the jet nozzle 8. In this way, the inert gas ejected by the jet nozzle 8 can blow away the neutral chemical liquid adhering to the surface of the titanium alloy, eliminating the need for manual labor or other additional tools to remove the neutral chemical liquid on the surface of the titanium alloy, and at the same time facilitating the operation and taking of the titanium alloy workpiece.

[0037] An embodiment of the present invention provides a method for laser polishing titanium alloy based on chemical assistance. The method for laser polishing titanium alloy based on chemical assistance includes the steps:

[0038] S100: Add sodium phosphate, potassium chloride, and calcium chloride to deionized water, stir and dissolve to obtain a neutral chemical solution, and heat it to 35 - 40 °C for heat preservation; wherein, the concentration of sodium phosphate in the neutral chemical solution is 10 - 15 g / mL, the concentration of potassium chloride is 4 - 6 g / mL, and the concentration of calcium chloride is 4 - 6 g / mL;

[0039] S200: Immerse the titanium alloy sample to be polished in a polishing tank 2 filled with flowing neutral chemical solution;

[0040] S300: Flush and fill an inert gas into the polishing tank 2;

[0041] S400: Laser polish the titanium alloy sample to be polished.

[0042] In the method for laser polishing titanium alloy based on chemical assistance of the present invention, the titanium alloy sample to be polished is immersed in a neutral chemical solution prepared from sodium phosphate, potassium chloride, and calcium chloride. At the same time, an inert gas is filled into the polishing tank 2 for polishing. The neutral chemical solution plays a role of airtight isolation of air, eliminating the cumbersome traditional airtight device. The neutral chemical solution is easy to prepare, has a high recycling rate, and the surface of the polished titanium alloy will not appear micro-pits and is smoother.

[0043] More importantly, compared with sodium nitrate, the neutral chemical solution component in the present invention adopts a sodium phosphate component. Sodium nitrate is a strong oxidant, its solution has strong corrosiveness, and it may decompose to produce harmful gases such as nitrogen oxides at high temperatures, posing potential risks to the environment and the health of operators. In contrast, sodium phosphate is a relatively mild chemical substance, and the waste generated during the polishing process has less pollution to the environment and lower harm to the health of operators. Sodium phosphate can provide a more stable chemical environment in the neutral chemical solution, which helps to better control the material removal rate and surface quality during the polishing process. Compared with sodium nitrate, when sodium phosphate interacts with the surface of titanium alloy, it may be more conducive to forming a uniform and dense oxide layer, thereby improving the surface finish and corrosion resistance after polishing.

[0044] In a neutral chemical solution, potassium chloride and calcium chloride provide chloride ions, potassium ions, and calcium ions in the neutral chemical solution. These ions can promote the micro-corrosion process on the surface of the titanium alloy, causing the micro-protrusions on the surface to dissolve preferentially, thereby further refining the surface microstructure and improving the surface flatness. At the same time, sodium phosphate can provide phosphate ions, which undergo chemical reactions on the surface of the titanium alloy to form a dense oxide film. This oxide film can effectively protect the surface of the titanium alloy and prevent it from being over-corroded or burned during the polishing process, thereby improving the surface finish and corrosion resistance after polishing.

[0045] Furthermore, based on using the neutral chemical solution to hermetically isolate air, the present invention also fills an inert gas into the polishing tank 2 in combination with the neutral chemical solution to jointly improve the polishing quality of the titanium alloy. Specifically, the stable chemical environment formed by sodium phosphate, potassium chloride, and calcium chloride in the neutral chemical solution, when an inert gas (such as argon) is introduced into the neutral chemical solution during the polishing process, can form a protective gas layer to prevent air from mixing into the neutral chemical solution. At the same time, both the flowing neutral chemical solution and the inert gas can carry away a large amount of heat and bubbles generated during the laser process in real time, achieving a comprehensive airtight seal for the titanium alloy.

[0046] In particular, the present invention further combines a flowing inert gas on the basis of the flowing neutral chemical solution, which can comprehensively and quickly carry away bubbles, prevent the appearance of cavitation pits on the surface of the titanium alloy, and at the same time can comprehensively and quickly carry away heat, making the polished surface smoother and comprehensively improving the polishing quality of the titanium alloy.

[0047] Specifically, after the neutral chemical solution is prepared, it needs to be heated and kept warm. If the temperature is too low, the solution viscosity is large, which is not conducive to polishing. If the temperature is too high, the activities of chloride ions and phosphate ions will increase, resulting in corrosion and burning phenomena on the surface of the titanium alloy. The heat preservation temperature adopted in the method of the present invention is 35 - 40 °C, preferably 37 °C for heat preservation.

[0048] Specifically, the process parameters of laser polishing are: laser power 300 - 500 W, scanning speed 400 - 800 mm / s, line spacing 0.02 - 0.06 mm, defocus amount +2 - +10 mm, and spot size 10 - 15 mm.

[0049] Specifically, after the titanium alloy sample to be polished is immersed in the polishing tank 2 filled with the neutral chemical solution, the distance between the surface of the titanium alloy sample to be polished and the liquid level of the neutral chemical solution is 20 - 40 mm. When the distance is too small, under the action of laser impact, the titanium alloy sample to be polished will be exposed to the air. When the distance is too large, the polishing roughness will increase.

[0050] An inert gas flows into the polishing box 2, and the intake and exhaust amounts of the inert gas are 300 - 500 mL / min. The inert gas can be introduced into the inert gas supply and recovery device 1, and a pressure valve is used to adjust the intake and exhaust amounts to 300 - 500 mL / min.

[0051] Furthermore, a neutral chemical liquid flows into the polishing box 2, and the inflow and outflow amounts of the neutral chemical liquid are 100 - 200 mL / min. The neutral chemical liquid is flowing during polishing. A water pump and a flow valve at the water outlet can be used to control the water inflow and outflow amounts to 100 - 200 mL / min, taking away the heat, bubbles, and other impurities generated by the laser and avoiding affecting the polishing effect.

[0052] Before immersing the titanium alloy sample to be polished in the polishing box 2 filled with the neutral chemical liquid, it also includes the step of cleaning the surface of the titanium alloy sample to be polished with 70% alcohol and then air-drying it. After cleaning the impurities on the surface with 75% alcohol, then immersing the titanium alloy sample to be polished in the neutral chemical liquid is beneficial to ensuring the polishing effect.

[0053] Specifically, the titanium alloy sample to be polished is Ti-6Al-4V titanium alloy. Ti-6Al-4V is also known as TC4 or Grade 5 titanium alloy, which is a widely used α+β type titanium alloy and is widely applied due to its excellent comprehensive properties. Ti-6Al-4V has a relatively high tensile strength (about 830 - 930 MPa) and yield strength (about 760 - 830 MPa), while maintaining good plasticity. Its density is about 4.5 g / cm 3 , and it has a high specific strength (strength / density), is suitable for applications where weight reduction is required, and shows excellent fatigue resistance under alternating loads.

[0054] Experimental Examples

[0055] 1. Pretreatment of the titanium alloy sample to be polished: The titanium alloy is processed by wire cutting into a titanium alloy sample to be polished with dimensions of 100 mm x 100 mm x 4 mm, the surface is cleaned with an X6140 universal milling machine, and the surface is cleaned with 70% alcohol and then air-dried.

[0056] 2. Use a portable roughness measuring instrument to measure the surface roughness of the titanium alloy sample to be polished, Sa = 2.32 μm.

[0057] 3. Prepare the neutral chemical liquid: Add 12.5 g of sodium phosphate, 4.95 g of sodium chloride, and 4.97 g of calcium chloride to 1000 ml of deionized water, stir until fully dissolved to obtain the neutral chemical liquid. Heat it to 37°C and keep it warm.

[0058] 4. Laser polishing treatment and process parameter setting: Place the titanium alloy sample to be polished, whose roughness has been measured, in the neutral chemical solution in step (3), submerge the titanium alloy sample to be polished, and the titanium alloy sample to be polished is 20 mm away from the solution surface. Turn on the inert gas supply and recovery device 11 and the water pump, and set the water inlet and outlet flow rates to 100 ml / min, and the gas inlet and outlet flow rates to 300 mL / min. On the automatic lifting table, set the laser power to 300 w, the scanning speed to 400 mm / s, the line spacing to 0.02 mm, the spot size to 10 mm, and the defocus amount to +2 mm. The number of scans is one, and the scanning area is 10 mm x 10 mm. Control the electric lifting table through the computer. According to the change in the thickness of the titanium alloy workpiece, the polishing position can be freely adjusted to make it in the focal position, and then start polishing.

[0059] Take out the polished titanium alloy sample to be polished, clean it with 70% alcohol, and dry it. Place it under a portable roughness measuring instrument and measure the roughness Sa = 0.4 um.

[0060] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. For those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some of the technical features can be equivalently replaced; and all such modifications and replacements should fall within the protection scope of the appended claims of the present invention.

Claims

1. A chemical-assisted laser polishing titanium alloy system, characterized in that It includes an inert gas supply and recovery device, a polishing box, a packing box, a laser, an electric lifting table, an electric pump, and a transparent sealing cover plate; The inert gas supply and recovery device and the packing box are respectively communicated with the polishing box. The laser is arranged above the polishing box. The electric lifting table is installed in the polishing box and is used to place the titanium alloy sample to be polished. The electric pump is installed in the packing box and is used to transport the neutral chemical liquid to the polishing box. The transparent sealing cover plate is covered on the polishing box to make the polishing process in an oxygen-free environment to avoid the oxidation reaction of the workpiece. The inert gas supply and recovery device is used to introduce inert gas above the liquid surface after the polishing box is filled with the neutral chemical liquid.

2. The laser polishing titanium alloy system according to claim 1, wherein A jet nozzle and a suction nozzle are arranged at the top of the inner side wall of the polishing box. The inert gas supply and recovery device is communicated with the jet nozzle through a gas supply pipeline, and the inert gas supply and recovery device is communicated with the suction nozzle through a gas return pipeline.

3. The laser polishing titanium alloy system according to claim 2, wherein, The electric lifting table can be lifted to the same height as the jet nozzle.

4. A method for laser polishing titanium alloy based on chemical assistance, applied to the laser polishing titanium alloy system according to any one of claims 1 to 3, characterized in that, It includes the steps: Adding sodium phosphate, potassium chloride, and calcium chloride to deionized water, stirring and dissolving to obtain a neutral chemical liquid, and heating to 35-40 °C for heat preservation; wherein, the concentration of sodium phosphate in the neutral chemical liquid is 10-15 g / mL, the concentration of potassium chloride is 4-6 g / mL, and the concentration of calcium chloride is 4-6 g / mL; Immersing the titanium alloy sample to be polished in the polishing box filled with flowing neutral chemical liquid; Filling the polishing box with flowing inert gas; Laser polishing the titanium alloy sample to be polished.

5. The laser polishing method for titanium alloy according to claim 4, characterized in that, The process parameters of the laser polishing are: laser power 300-500 W, scanning speed 400-800 mm / s, line spacing 0.02-0.06 mm, defocus amount +2-+10 mm, and spot size 10-15 mm.

6. The laser polishing method for titanium alloy according to claim 4, characterized in that, After the titanium alloy sample to be polished is immersed in the polishing box filled with the neutral chemical liquid, the distance from the surface of the titanium alloy sample to be polished to the liquid surface of the neutral chemical liquid is 20-40 mm.

7. The laser polishing method for titanium alloy according to claim 4, characterized in that, The inert gas flows into the polishing box, and the intake and exhaust amounts of the inert gas are 300-500 mL / min.

8. The laser polishing method for titanium alloy according to claim 7, characterized in that, The neutral chemical liquid flows into the polishing box, and the inflow and outflow amounts of the neutral chemical liquid are 100-200 mL / min.

9. The laser polishing method for titanium alloy according to any one of claims 4 to 8, characterized in that, Before immersing the titanium alloy sample to be polished in the polishing box filled with the neutral chemical liquid, it also includes the step: Cleaning the surface with 70% alcohol and then air-drying the titanium alloy sample to be polished.

10. The laser polishing method for titanium alloy according to any one of claims 4 to 8, characterized in that The titanium alloy sample to be polished is Ti-6Al-4V titanium alloy.

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