Pipeline cleaning method

Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to a pipeline cleaning method. The method comprises the following steps that machining, fluid polishing, electrolytic polishing, passivating, cleaning and drying are conducted on the pipeline; according to the pipeline cleaning method, pollutants such as dust particles, oil stains, smudginess and metal ions on the inner wall and the outer surface of the pipeline can be cleaned, and the cleaned pipeline is low in roughness and high in cleanliness.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to a pipeline cleaning method. Background Art

[0002] Specialty gases are special high-purity gases used in the production of various electronic products such as semiconductors, liquid crystals, and solar cells. Specifically in the semiconductor field, specialty gases are used to make semiconductors, etch (for semiconductor micro-processing), and clean production equipment.

[0003] The special gas pipeline is a connecting pipe used to transport special gases from gas cylinders to the interface of the equipment. It is generally a stainless steel pipe. The cleanliness of the stainless steel clean pipe is very important in the high-purity special gas system and directly affects the quality of the products produced.

[0004] The roughness of the inner surface of the pipe is a measure of the quality of the pipe. The lower the roughness, the less likely it is to carry particles. During the stainless steel smelting process, the clean gas pipeline can absorb about 200g of gas per ton. After the stainless steel is processed, not only are there various pollutants on its surface, but also a certain amount of gas is absorbed in its metal lattice. When there is airflow in the pipeline, the gas absorbed by the metal will re-enter the airflow and pollute the pure gas.

[0005] Therefore, for semiconductor special gas pipelines, ultra-high cleanliness and low roughness are very important to ensure their product quality. However, the cleanliness and roughness of materials treated by existing surface treatment technology cannot meet existing needs. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects of poor cleanliness and high roughness of semiconductor special gas pipelines after being treated by existing cleaning technology, thereby providing a pipeline cleaning method.

[0007] To this end, the present invention provides the following technical solutions:

[0008] A first aspect of the present invention protects a pipeline cleaning method, wherein the method comprises the following steps: machining, fluid polishing, electrolytic polishing, passivation, cleaning, and drying the pipeline.

[0009] In the present invention, the water used for cleaning has a resistivity of ≥2MΩ, preferably ≥4MΩ, and a copper content of <30ppb at 25°C. If these conditions are not met, the water should be replaced.

[0010] In the present invention, the average diameter of the pipeline is 6-10 mm, and the length is selected according to needs.

[0011] According to the present invention, the machining comprises the following steps: removing burrs and trimming the ends of the pipeline to obtain a machined pipeline.

[0012] According to the present invention, the Ra of the inner wall of the pipeline after machining is less than 0.4 μm.

[0013] In the present invention, Ra refers to surface roughness, and a roughness meter is used to detect the Ra value of the inner wall of the pipeline.

[0014] According to the present invention, the fluid polishing comprises the following steps: polishing the inner wall of the machined pipeline by using abrasive flow.

[0015] According to the present invention, the average particle size of the abrasive particles is 20-220 meshes.

[0016] According to the present invention, the flow rate of the abrasive flow is 1-3 m / s, and the time is 120-300 s; optionally, the flow rate of the abrasive flow is 1.5-2.5 m / s, and the polishing time is 180-240 s.

[0017] In the present invention, the abrasive grains are solid; the abrasive grains include at least one of silicon carbide and brown corundum.

[0018] In the present invention, the Ra of the inner wall of the semiconductor special gas pipeline after fluid polishing is less than 0.1 μm.

[0019] According to the present invention, the electrolytic polishing includes the following steps: placing the fluid-polished pipeline in an acid solution for electrolytic polishing, the electrolytic polishing temperature is 55-65°C, the voltage is 5-15V, the current is 260-320A, and the time is 20-60s; optionally, the electrolytic polishing temperature is 58-62°C, the voltage is 8-12V, the current is 280-300A, and the time is 30-55s.

[0020] According to the present invention, based on the mass of the acid solution, the acid solution includes 50-65wt% phosphoric acid, 20-35wt% sulfuric acid, 0.6-1wt% gluconic acid, 0.6-1wt% ammonium sulfate, and the remainder is water.

[0021] In the present invention, during electrolytic polishing, the anode is kept oscillating and air stirring is turned on to make the cleaning more complete; in the present invention, after electrolytic polishing, the electrolytic polishing product is immediately taken out from the acid tank and fully washed with water to prevent spots, and the cleaning time is generally 3-5 minutes.

[0022] In the present invention, electrolytic polishing uses the workpiece to be polished as the anode and the insoluble metal as the cathode. Typically, but not limiting, the cathode material includes a lead plate or a stainless steel plate. The two electrodes are immersed in the electrolytic cell at the same time, and direct current is passed to produce selective anode dissolution, thereby achieving the effect of increasing the brightness of the workpiece surface.

[0023] In the present invention, the passivation solution used is a conventional solution in the art, typically but not limitingly, a nitric acid solution with a content of 50 (% v / v). Passivation can prevent the pipeline from being corroded; the passivation time is 30-45 minutes.

[0024] According to the present invention, the cleaning comprises the following steps: the pipeline after passivation treatment is sequentially subjected to degreasing cleaning, first overflow cleaning, pickling, second overflow cleaning, high-pressure jet cleaning, and third overflow cleaning.

[0025] In the present invention, the degreasing cleaning is carried out in an ultrasonic environment, the ultrasonic frequency is 30-50kHz, the current is 4.5-6.5A, the cleaning temperature is 50-60°C, and the cleaning time is 5-15min.

[0026] In the present invention, a degreasing agent is used for degreasing and cleaning, and the degreasing agent is a conventional degreasing agent in the art, typically but not limitedly, including at least one of ISOPREP 49L (purchased from MacDermid) and RC-152.

[0027] In the present invention, the concentration of the degreasing agent is 15-20 (% v / v) based on the volume percentage of the degreasing cleaning solution.

[0028] In the present invention, at room temperature, the time of the first overflow cleaning is 2-5 minutes.

[0029] In the present invention, the pickling is carried out using a nitric acid solution; the concentration of the nitric acid is 50-60 (% v / v) based on the volume percentage of the nitric acid solution; and the pickling time is 3-5 minutes.

[0030] In the present invention, at room temperature, the time of the second overflow cleaning is 2-5 minutes.

[0031] According to the present invention, the pressure of the high-pressure jet cleaning is 200-900PSI, the water spraying distance is 10-20cm, and the time is 5-10min.

[0032] In the present invention, the water spraying distance is the distance between the nozzle and the pipeline.

[0033] In the present invention, the temperature of the third overflow cleaning is 25-50°C and the time is 2-5 minutes; optionally, the temperature is 35-50°C.

[0034] In the present invention, the drying is carried out in a nitrogen environment with a purity of 99.999%; the nitrogen is filtered by a filter element with a gas outlet of 0.01 μm, so that the nitrogen maintains a purity of 99.999% and prevents the attachment of pollutants.

[0035] The present invention also includes the step of packaging the dried material, specifically: in a vacuum environment, using a thousand-level dust-free cloth to package the cleaned special gas pipeline for easy transportation and storage.

[0036] The second aspect of the present invention protects the application of the aforementioned pipeline cleaning method in special gas pipeline cleaning.

[0037] The technical solution of the present invention has the following advantages:

[0038] 1. The present invention provides a pipeline cleaning method, wherein the method comprises the following steps: machining, fluid polishing, electrolytic polishing, passivation, cleaning, and drying the pipeline; the method of the present invention can remove pollutants such as dust particles, oil stains, dirt, and metal ions on the inner wall of the pipeline, so that the cleaned pipeline has excellent cleanliness and low pipeline roughness. During the cleaning process, fluid polishing is first performed to remove burrs and pollutant particles that are not removed cleanly during machining, and then electrolytic polishing is performed to remove fine lines and pollutant particles; the synergistic effect of fluid polishing and electrolytic polishing performed in a specific order improves the processing efficiency, and can ultimately effectively remove pollutants and reduce the roughness of the pipeline.

[0039] 2. The specific conditions of fluid polishing in the present invention can further reduce the roughness of the inner wall surface of the pipeline, and then round the sharp corners at the intersection to ensure smooth transition of the pipeline and improve the fatigue resistance of the parts.

[0040] 3. The specific conditions of electrolytic polishing in the present invention can further reduce the roughness of the inner wall surface of the pipeline, improve the cleanliness, and can further reduce energy consumption and improve efficiency while achieving polishing.

[0041] 4. The specific cleaning steps in the present invention are performed multiple times in the order of degreasing cleaning, first overflow cleaning, pickling, second overflow cleaning, high-pressure jet cleaning, and third overflow cleaning, which can further remove pollutants such as metal ions on the inner wall of the pipeline, improve the cleanliness of the pipeline surface, and reduce the roughness. DETAILED DESCRIPTION

[0042] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0043] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0044] The water used in the examples and comparative examples of the present invention is pure water, with a resistivity of ≥2MΩ at 25°C and a copper content of <30ppb;

[0045] The cathodes used in the embodiments and comparative examples of the present invention are both lead plates.

[0046] Example 1

[0047] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0048] Step 1, deburring and trimming the semiconductor special gas pipeline, and the Ra of the inner wall of the pipeline after machining is 0.38μm;

[0049] Step 2, using silicon carbide with an average particle size of 180 mesh to perform fluid polishing on the inner wall of the pipeline, the time is 180 seconds, the flow rate of the abrasive flow is 1.5 m / s, and the Ra of the inner wall of the pipeline after fluid polishing is 0.08 μm;

[0050] Step 3, electropolishing the pipeline, keeping the anode swinging while turning on air stirring during electropolishing, the acid solution has a phosphoric acid content of 53wt%, a sulfuric acid content of 28wt%, 0.6wt% gluconic acid, 0.6wt% ammonium sulfate, and the remainder is water, the electropolishing temperature is 60°C, the voltage is 8V, the current is 300A, and the time is 30s. After the electropolishing is completed, the pipeline is immediately placed in pure water for cleaning, and the overflow and air stirring are turned on for 3min;

[0051] Step 4, placing the cleaned pipeline into 1440L of 50% (v / v) nitric acid solution for passivation for 30 minutes;

[0052] Step 5, degreasing and cleaning, the pipeline is placed in an ultrasonic cleaning tank filled with 1800L of degreasing and cleaning solution for cleaning, the tank solution contains ISOPREP 49L with a concentration of 15 (% v / v), an ultrasonic frequency of 35kHz, a current of 4.5A, a cleaning temperature of 50°C, and a cleaning time of 5min;

[0053] For the first overflow cleaning, the pipeline is placed in pure water for overflow cleaning, and the cleaning time is 2 minutes;

[0054] Acid cleaning: put the pipeline into 1440L of 50% v / v nitric acid for cleaning for 3 minutes;

[0055] The second overflow cleaning, put the pipeline into pure water for overflow cleaning, the cleaning time is 2 minutes;

[0056] High-pressure jet cleaning: flush the pipeline with a water spray gun. The pressure of high-pressure jet cleaning is 200PSI, the water spray distance is 10cm, and the time is 5min;

[0057] The third overflow cleaning, put the pipeline into pure water for overflow cleaning, the water washing temperature is 39℃, and the cleaning time is 3min;

[0058] Step 6, drying, using nitrogen filtered by a filter with a pore size of 0.01 μm, the purity of the nitrogen is 99.999%, and the pipeline is blown dry with nitrogen, and the Ra of the inner wall of the pipeline after drying is 0.01 μm.

[0059] Example 2

[0060] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 9.6 mm, which is specifically as follows:

[0061] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0062] Step 5, degreasing and cleaning, the pipeline is placed in an ultrasonic cleaning tank filled with 1800L of cleaning solution for cleaning, the tank solution contains ISOPREP 49L with a concentration of 15 (% v / v), an ultrasonic frequency of 45kHz, a current of 6.5A, a cleaning temperature of 55°C, and a cleaning time of 10min;

[0063] For the first overflow cleaning, the pipeline is placed in pure water for overflow cleaning, and the cleaning time is 2 minutes;

[0064] Acid cleaning: put the pipeline into 1440L of 50% v / v nitric acid for cleaning for 5 minutes;

[0065] The second overflow cleaning, put the pipeline into pure water for overflow cleaning, the cleaning time is 2 minutes;

[0066] High-pressure jet cleaning: flush the pipeline with a water spray gun. The pressure of high-pressure jet cleaning is 900PSI, the water spray distance is 19cm, and the time is 10min;

[0067] The third overflow cleaning, put the pipeline into pure water for overflow cleaning, the water washing temperature is 45℃, and the cleaning time is 5min;

[0068] Step 6, drying, using nitrogen filtered by a filter with a pore size of 0.01 μm, the purity of the nitrogen is 99.999%, and the pipeline is blown dry with nitrogen, and the Ra of the inner wall of the pipeline after drying is 0.02 μm.

[0069] Example 3

[0070] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0071] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0072] Step 5 is carried out according to Step 5 in Example 1, except that “degreasing cleaning, placing the pipeline in an ultrasonic cleaning tank filled with 1800 L of degreasing cleaning solution for cleaning, the tank solution contains ISOPREP 49L with a concentration of 15 (% v / v), an ultrasonic frequency of 35 kHz, a current of 4.5 A, a cleaning temperature of 50° C., and a cleaning time of 5 min; first overflow cleaning, placing the pipeline in pure water for overflow cleaning, and the cleaning time is 2 min” is changed to “first overflow cleaning, placing the pipeline in pure water for overflow cleaning, and the cleaning time is 7 min”;

[0073] Step 6, according to the method of step 6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.03 μm.

[0074] Example 4

[0075] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0076] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0077] Step 5, degreasing and cleaning, the pipeline is placed in an ultrasonic cleaning tank filled with 1800L of cleaning solution for cleaning, the tank solution contains ISOPREP 49L with a concentration of 15 (% v / v), an ultrasonic frequency of 35kHz, a current of 4.5A, a cleaning temperature of 50°C, and a cleaning time of 5min;

[0078] For the first overflow cleaning, the pipeline is placed in pure water for overflow cleaning, and the cleaning time is 2 minutes;

[0079] The second overflow cleaning, put the pipeline into pure water for overflow cleaning, the cleaning time is 5 minutes;

[0080] High-pressure jet cleaning: flush the pipeline with a water spray gun. The pressure of high-pressure jet cleaning is 200PSI, the water spray distance is 10cm, and the time is 5min;

[0081] The third overflow cleaning, put the pipeline into pure water for overflow cleaning, the water washing temperature is 39℃, and the cleaning time is 3min;

[0082] Step 6, according to the method of step 6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.025 μm.

[0083] Example 5

[0084] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0085] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0086] Step 5, degreasing and cleaning, the pipeline is placed in an ultrasonic cleaning tank filled with 1800L of cleaning solution for cleaning, the tank solution contains ISOPREP 49L with a concentration of 15 (% v / v), an ultrasonic frequency of 35kHz, a current of 4.5A, a cleaning temperature of 50°C, and a cleaning time of 5min;

[0087] For the first overflow cleaning, the pipeline is placed in pure water for overflow cleaning, and the cleaning time is 2 minutes;

[0088] Acid cleaning: put the pipeline into 50% v / v nitric acid for cleaning for 3 minutes;

[0089] The second overflow cleaning, put the pipeline into pure water for overflow cleaning, the cleaning time is 7 minutes;

[0090] The third overflow cleaning, put the pipeline into pure water for overflow cleaning, the water washing temperature is 39℃, and the cleaning time is 3min;

[0091] Step 6, according to the method of step 6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.032 μm.

[0092] Example 6

[0093] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0094] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0095] Step 5, in the same manner as step 5 in Example 1, except that the temperature of the third overflow cleaning is 25°C;

[0096] Step 6, according to the method of step 6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.025 μm.

[0097] Example 7

[0098] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0099] Step 1, according to the method of step 1 in Example 1;

[0100] Step 2, in the same manner as in Example 1, except that silicon carbide with an average particle size of 240 mesh is used to perform fluid polishing on the inner wall of the pipeline, the time is 120 s, the flow rate of the abrasive flow is 2 m / s, and the Ra of the inner wall of the pipeline after fluid polishing is 0.1 μm.

[0101] Step 3-6, according to the method of step 3-6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.05 μm.

[0102] Example 8

[0103] This embodiment provides a method for cleaning a semiconductor special gas pipeline with a length of 1000 mm and a diameter of 6.35 mm, which is specifically as follows:

[0104] Steps 1 and 2 are carried out in the same manner as steps 1 and 2 in Example 1;

[0105] Step 3, in the same manner as in Example 1, except that "the electrolytic polishing temperature is 60° C., the voltage is 8 V, the current is 300 A, and the time is 30 s" is changed to "the electrolytic polishing temperature is 65° C., the voltage is 5 V, the current is 280 A, and the time is 60 s";

[0106] Step 4-6, according to the method of step 4-6 in embodiment 1, the Ra of the inner wall of the pipeline after drying is 0.058 μm.

[0107] Comparative Example 1

[0108] This comparative example provides a method for cleaning a semiconductor special gas pipeline with a length of 1000mm and Ф10mm, as follows:

[0109] Step 1, according to the method of step 1 in embodiment 2;

[0110] Step 2, electropolishing the pipeline, keeping the anode swinging while turning on air stirring during electropolishing, the acid solution has a phosphoric acid content of 53wt%, a sulfuric acid content of 28wt%, 0.6wt% gluconic acid, 0.6wt% ammonium sulfate, and the remainder is water, the electropolishing temperature is 60°C, the voltage is 8V, the current is 300A, and the time is 30s. After the electropolishing is completed, the pipeline is immediately placed in pure water for cleaning, and the overflow and air stirring are turned on for 3min;

[0111] Step 3, using silicon carbide with an average particle size of 180 mesh to perform fluid polishing on the inner wall of the pipeline for 180 seconds, and the flow rate of the abrasive flow is 1.5 m / s;

[0112] Step 4-6, according to the method of step 4-6 in embodiment 2, the Ra of the inner wall of the pipeline after drying is 0.073μm.

[0113] Comparative Example 2

[0114] This comparative example provides a method for cleaning a semiconductor special gas pipeline with a length of 1000mm and Ф10mm, as follows:

[0115] The method of Example 3 is different in that all the operations of step 1 are not performed, and the Ra of the inner wall of the pipeline after drying is 1.32 μm.

[0116] Comparative Example 3

[0117] This comparative example provides a method for cleaning a semiconductor special gas pipeline with a length of 1000mm and Ф10mm, as follows:

[0118] Steps 1-4 are carried out in the same manner as steps 1-4 in Example 1;

[0119] Step 5, drying, using nitrogen filtered by a filter with a pore size of 0.01 μm, the purity of the nitrogen is 99.999%, and the pipeline is blown dry with nitrogen, and the Ra of the inner wall of the pipeline after drying is 0.063 μm.

[0120] The present invention also includes vacuum packaging the pipes of the embodiment and the comparative example after being blown dry using a class 1000 dust-free cloth in a class 1000 dust-free room to facilitate storage and transportation.

[0121] Test example

[0122] The cleanliness test was performed on the inner wall of the pipe after drying in the embodiment and the comparative example. The specific method used an ion chromatograph. The specific process was 25°C, the pipe was rinsed with 1200L of water for 5 minutes to obtain an extract, and ultrapure water was used as the eluent for testing. The specific test results are shown in Table 1.

[0123] Table 1 Particle test on pipeline surface of embodiment and comparative example

[0124]

[0125]

[0126] Table 1 (Continued) Particle Test on Pipeline Surface of Example and Comparative Example

[0127]

[0128]

[0129] It can be seen from the data in Table 1 that the pipeline obtained by the pipeline cleaning method of the present invention has low roughness, low surface particle content and excellent cleanliness.

[0130] Comparing Example 1 with Examples 3-6, it can be seen that in the specific cleaning steps of the present invention, the synergistic effect of multiple cleanings can further reduce the surface roughness of the pipeline and improve the cleanliness.

[0131] Comparing Example 1 with Example 7, it can be seen that the specific fluid polishing conditions enable the abrasive particles to fully exert their effects, resulting in low roughness and cleanliness of the resulting pipeline surface.

[0132] Comparing Example 1 with Example 8, it can be seen that specific electrolytic polishing conditions can further reduce the roughness of the inner wall surface of the pipeline, improve the cleanliness, and can further reduce energy consumption and improve efficiency while achieving polishing.

[0133] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A pipeline cleaning method, characterized in that: The method comprises the following steps: machining, fluid polishing, electrolytic polishing, passivation, cleaning and drying the pipeline.

2. The pipeline cleaning method according to claim 1, characterized in that: The fluid polishing comprises the following steps: polishing the inner wall of the machined pipeline by using abrasive flow.

3. The pipeline cleaning method according to claim 2, characterized in that: The average particle size of the abrasive particles is 20-220 mesh; And / or, the flow rate of the abrasive flow is 1-3 m / s, and the time is 120-300 s; And / or, the abrasive particles are solid; the abrasive particles include at least one of silicon carbide and brown corundum.

4. The pipeline cleaning method according to claim 3, characterized in that: The flow rate of the abrasive flow is 1.5-2.5 m / s, and the polishing time is 180-240 s.

5. The pipeline cleaning method according to any one of claims 1 to 4, characterized in that: The electrolytic polishing comprises the following steps: placing the fluid-polished pipeline in an acid solution for electrolytic polishing, wherein the electrolytic polishing temperature is 55-65° C., the voltage is 5-15V, the current is 260-320A, and the time is 20-60s.

6. The pipeline cleaning method according to claim 5, characterized in that: The electrolytic polishing temperature is 58-62° C., the voltage is 8-12 V, the current is 280-300 A, and the time is 30-55 s.

7. The pipeline cleaning method according to claim 5, characterized in that: Calculated by the mass of the acid solution, the acid solution comprises 50-65wt% of phosphoric acid, 20-35wt% of sulfuric acid, 0.6-1wt% of gluconic acid, 0.6-1wt% of ammonium sulfate, and the balance is water.

8. The pipeline cleaning method according to any one of claims 1 to 7, characterized in that: The cleaning comprises the following steps: sequentially performing degreasing cleaning, first overflow cleaning, pickling, second overflow cleaning, high-pressure jet cleaning, and third overflow cleaning on the passivated pipeline; Optionally, the pressure of the high-pressure jet cleaning is 200-900PSI, the water spraying distance is 10-20cm, and the time is 5-10min.

9. The pipeline cleaning method according to claim 1, characterized in that: The machining process comprises the following steps: removing burrs and trimming the ends of the pipeline to obtain a machined pipeline; Optionally, the Ra of the machined inner wall of the pipeline is less than 0.4 μm.

10. Application of the pipeline cleaning method according to any one of claims 1 to 9 in cleaning special gas pipelines.

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