Cold-formed thin-walled section steel production pretreatment process

Abstract

The invention relates to the technical field of cold-formed thin-walled section steel production, and discloses a cold-formed thin-walled section steel production pretreatment process which comprises a workbench, a spraying assembly is fixedly connected to the upper surface of the workbench, a support is fixedly connected to the upper surface of the workbench, and a motor is fixedly connected to the outer wall of the right side of the support; the output end of the motor is fixedly connected with a rotating disc, the outer wall of the rotating disc is fixedly connected with a first fixing shaft, the outer wall of the first fixing shaft is slidably connected with a rotating toothed plate, the outer wall of the left side of the support is fixedly connected with a second fixing shaft, and the interior of the support is slidably connected with a toothed shaft. The motor is started to drive the rotating disc to rotate, the rotating disc drives the rotating toothed plate to slide, the rotating toothed plate drives the spraying head to spray, the reciprocating spraying motion track can ensure that coating liquid evenly covers the surface of steel, multiple times of reciprocating motion can supplement coating uneven areas possibly occurring in the coating process, coating thickness fluctuation is reduced, and the coating quality is improved. And the uniformity of the coating is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of cold-bent thin-walled steel production, in particular to a cold-bent thin-walled steel production pretreatment process. Background Art

[0002] Cold-bent thin-walled steel is widely used in construction, machinery manufacturing, automobile manufacturing, home appliances and other fields due to its advantages such as light weight, high strength and easy processing.

[0003] The traditional pretreatment process for cold-bent thin-walled steel production will cause defects such as missing coating, accumulation, and sagging on the coating surface during nano-spraying. One spraying cannot cover all surfaces, especially at the edges and recessed areas of the steel, which are prone to incomplete coverage, resulting in an uneven coating surface. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a cold-bent thin-walled steel production pretreatment process to solve the problem that the coating surface is not uniform when nano-spraying is performed in the traditional cold-bent thin-walled steel production pretreatment process.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a cold-bent thin-walled steel production pretreatment device, including a workbench, a spray assembly fixedly connected to the upper surface of the workbench, a bracket fixedly connected to the upper surface of the workbench, a motor fixedly connected to the right outer wall of the bracket, a turntable fixedly connected to the outer wall of the turntable, a fixed shaft 1 fixedly connected to the outer wall of the fixed shaft 1 is slidably connected to a rotating gear plate, a fixed shaft 2 is fixedly connected to the outer wall of the fixed shaft 1, the rotating gear plate is rotatably connected to the outer wall of the fixed shaft 2, the bracket is slidably connected to a gear shaft, and the outer wall of the rotating gear plate is meshingly connected to the outer wall of the gear shaft.

[0006] Preferably, the spray assembly includes a storage box, the interior of the storage box is fixedly connected to a pipe, an end of the pipe away from the storage box is fixedly connected to a spray head, and the upper surface of the spray head is fixedly connected to the outer wall of the gear shaft.

[0007] Preferably, a hydraulic rod is fixedly connected to the upper surface of the workbench, a fixed plate is fixedly connected to the output end of the hydraulic rod, a slider is fixedly connected to the lower surface of the fixed plate, a slide groove is provided inside the workbench, an outer wall of the slider is slidably connected to the inside of the slide groove, and a collection component is slidably connected to the outer wall of the workbench.

[0008] Preferably, the collecting component comprises a collecting frame, the outer wall of the collecting frame is slidably connected to the outer wall of the workbench, the outer wall of the collecting frame is fixedly connected to a slider 2, a sliding groove is provided inside the workbench, the outer wall of the slider 2 is slidably connected to the inside of the sliding groove, and the outer wall of the collecting frame is fixedly connected to a handle.

[0009] Preferably, the cold-bent thin-walled steel production pretreatment process comprises the following steps:

[0010] S1: Surface inspection and cleaning

[0011] First, use the detection equipment to check the steel surface to determine whether there are cracks, bubbles, rust spots on the surface. Then, mechanical sandblasting and chemical cleaning are used to remove the oxide scale, rust spots and oil stains on the steel surface.

[0012] S2: Pickling

[0013] Immerse the steel in a pickling tank and use hydrochloric acid or sulfuric acid solution to remove oxides and rust on the steel surface. After pickling, rinse the steel thoroughly with clean water;

[0014] S3: Nano coating pre-treatment process

[0015] A layer of nano-scale oxide or silane coating is applied on the surface of the pickled steel, and the nano-coating liquid is evenly distributed on the surface of the steel by spraying. After coating, it is cured by low-temperature baking to form an ultra-thin nano-coating;

[0016] S4: Phosphate

[0017] The steel is immersed in the phosphating solution to form a phosphate film on the surface. After phosphating, the steel is passivated. After the treatment is completed, it is rinsed with clean water again;

[0018] S5: Micro-arc oxidation pretreatment process

[0019] The steel is placed in an electrolyte containing sodium salt, potassium salt, silicate and borate, and a high-voltage pulse current is applied to generate micro-arc discharge on the surface of the steel to form a ceramic oxide film. After oxidation, the steel is cooled and cleaned;

[0020] S6: Plasma Surface Activation

[0021] Before oiling, the steel surface is treated with oxygen or argon plasma. Plasma treatment activates chemical groups on the steel surface.

[0022] S7: Oiling

[0023] After the surface treatment is completed, a layer of anti-rust oil is evenly applied to the surface of the steel. The anti-rust oil is evenly applied on the surface of the steel through automatic oil spraying equipment. After oiling, the steel is left to stand for a period of time;

[0024] S8: Anti-fingerprint coating

[0025] Using silicone resin or fluorine-containing polymer, an anti-fingerprint coating is formed on the surface of the steel by spraying or dipping, and then the steel is cured to form a surface protection layer.

[0026] Preferably, in step S1, an eddy current flaw detector or an ultrasonic detector is used to conduct a comprehensive inspection of the steel surface;

[0027] Then use sandblasting equipment to mechanically clean the steel surface, the sandblasting pressure is set to 0.3-0.6MPa, and 80-120 mesh abrasive is used;

[0028] After mechanical cleaning, use 2%-5% alkaline solution or 0.5%-1.0% acidic solution to chemically clean the steel surface. The temperature is controlled at 30℃-50℃ and the cleaning time is 3-10 minutes. After cleaning, rinse with clean water to remove residual chemicals.

[0029] Preferably, in the step S2, 10%-15% hydrochloric acid or sulfuric acid solution is used as the pickling liquid;

[0030] Immerse the steel in the pickling tank, control the temperature at 50℃-60℃, and the pickling time is 5-15 minutes;

[0031] After pickling, immediately rinse the steel surface with clean water at 20℃-30℃.

[0032] Preferably, in the step S3, nano-alumina or nano-silane is prepared into a 1%-5% nano-coating liquid, deionized water or ethanol is used as a solvent, ultrasonically stirred for 30 minutes, and then placed in a storage box;

[0033] Then, the steel is placed on the upper surface of the workbench, and the hydraulic rod is turned on. The hydraulic rod pushes the fixed plate to slide. When the fixed plate slides, it drives the slider 1 to slide inside the slide groove 1, and the fixed plate pushes the steel to be fixed on the outer wall of the bracket. Then, the motor is turned on, and the motor drives the turntable to rotate. When the turntable rotates, it drives the rotating gear plate to slide on the outer wall of the fixed shaft 1. When the rotating gear plate slides on the outer wall of the fixed shaft 1, its inside will rotate on the outer wall of the fixed shaft 2. When the rotating gear plate rotates, it drives the gear shaft to slide. When the gear shaft slides, it drives the nozzle to spray the steel clamped and fixed by the fixed plate and the bracket. The coating thickness is controlled between 10-50 nanometers.

[0034] After coating, take out the steel and put it into a low-temperature oven with the temperature set at 80℃-120℃ for 10-15 minutes to cure the coating. After curing, cool it and rinse the surface with deionized water, and finally air dry it.

[0035] Preferably, in the step S4, a 5%-10% phosphoric acid solution is used as the phosphating solution, the temperature is controlled at 60°C-80°C, the steel is immersed in the phosphating solution for 10-20 minutes, and a passivation treatment is performed immediately after phosphating, a 1%-3% chromate solution is used for surface passivation, the treatment time is 5-10 minutes, and the steel is rinsed with clean water after passivation.

[0036] Preferably, in the step S5, the electrolyte is prepared by mixing 5-10 g / L of sodium salt, 1-3 g / L of potassium salt, 10-20 g / L of silicate and 2-5 g / L of borate, the steel is connected as the anode, the stainless steel plate is used as the cathode, the power supply voltage is set to 300-600 V, and the current density is 10-30 A / dm 2 The treatment time is 5-20 minutes. Under the action of high-voltage pulse current, micro-arc discharge occurs on the steel surface, forming a 2-10 micron ceramic oxide film.

[0037] After micro-arc oxidation, the steel surface was cleaned with deionized water to remove residual electrolyte, and then naturally cooled in air;

[0038] In the step S6, the steel is placed in a plasma treatment chamber, a radio frequency voltage of 13.56 MHz is applied, the power is controlled at 50-300 W, and the treatment time is 1-5 minutes;

[0039] In the step S7, light mineral oil or synthetic oil is selected as the rust-proof oil;

[0040] Use automatic oil spraying equipment to evenly coat the steel surface, and the coating thickness is controlled at 3-5 microns. After oiling, the steel is left to stand at room temperature for 10-15 minutes;

[0041] In the step S8, the anti-fingerprint coating material includes silicone resin or fluorine-containing polymer, and the coating thickness is controlled between 1-3 microns. After coating, it is cured at 150° C.-200° C. for 10-20 minutes.

[0042] The present invention provides a pretreatment process for cold-bent thin-walled steel production. It has the following beneficial effects:

[0043] 1. The present invention starts the motor to drive the turntable to rotate, the turntable drives the rotating tooth plate to slide, and the rotating tooth plate drives the nozzle to spray. The reciprocating spraying motion trajectory can ensure that the coating liquid is evenly covered on the steel surface. Multiple reciprocating motions can supplement the uneven coating areas that may occur during coating, reduce the fluctuation of coating thickness, and ensure the uniformity of the coating.

[0044] 2. The present invention significantly improves the corrosion resistance of steel by using a micro-arc oxidation process after pickling and phosphating, making it perform well in corrosive environments such as high humidity, high salinity, acid and alkali. This improvement makes cold-bent thin-walled steel suitable for extreme corrosive environments such as marine engineering and chemical equipment.

[0045] 3. The nano coating pretreatment, plasma surface activation and other processes of the present invention significantly improve the adhesion of the coating on the steel surface, preventing the coating from falling off or peeling off during subsequent use. The enhanced adhesion makes the cold-bent thin-walled steel more stable during the coating or plating process, and is suitable for applications with high coating quality requirements.

[0046] 4. The ceramic oxide film formed on the steel surface by micro-arc oxidation treatment of the present invention significantly improves the surface hardness and wear resistance, and is suitable for use in high-friction and high-wear environments, such as the manufacture of mechanical parts and tools. This wear resistance extends the service life of the steel and reduces maintenance costs.

[0047] 5. The present invention enhances the durability of the coating in long-term use through optimized phosphating, passivation and anti-fingerprint treatment, ensuring that the coating can still maintain its protective function and aesthetics when exposed to harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a process flow chart of the pretreatment process for cold-bent thin-walled steel production of the present invention;

[0049] Figure 2 It is a schematic diagram of the overall structure of the pretreatment device of the present invention;

[0050] Figure 3 It is a schematic structural diagram of the power transmission part of the spray assembly of the present invention;

[0051] Figure 4 The present invention Figure 2 Schematic diagram of the rear structure;

[0052] Figure 5 A schematic diagram of the structure of the clamping part of the present invention;

[0053] Figure 6 It is a schematic diagram of the structure of the collection component of the present invention.

[0054] Among them, 1. workbench; 2. bracket; 3. motor; 4. turntable; 5. fixed axis 1; 6. rotating gear plate; 7. fixed axis 2; 8. gear shaft; 9. spray assembly; 901. storage box; 902. pipeline; 903. nozzle; 10. hydraulic rod; 11. fixed plate; 12. slide 1; 13. slider 1; 14. slide; 15. collection assembly; 1501. collection frame; 1502. slider 2; 1503. handle. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Please refer to the attached Figures 2 to 6 As shown, the embodiment of the present invention provides a cold-bent thin-walled steel production pretreatment device, including a workbench 1, a spray assembly 9 is fixedly connected to the upper surface of the workbench 1, a bracket 2 is fixedly connected to the upper surface of the workbench 1, a motor 3 is fixedly connected to the right outer wall of the bracket 2, a turntable 4 is fixedly connected to the output end of the motor 3, a fixed shaft 1 5 is fixedly connected to the outer wall of the turntable 4, a rotating tooth plate 6 is slidably connected to the outer wall of the fixed shaft 1 5, a fixed shaft 2 7 is fixedly connected to the left outer wall of the bracket 2, the inner part of the rotating tooth plate 6 is rotatably connected to the outer wall of the fixed shaft 2 7, a gear shaft 8 is slidably connected to the inner part of the bracket 2, and the outer wall of the rotating tooth plate 6 is meshedly connected to the outer wall of the gear shaft 8. The spray assembly 9 includes a storage box 901, a pipe 902 is fixedly connected to the inner part of the storage box 901, a nozzle 903 is fixedly connected to the end of the pipe 902 away from the storage box 901, and the upper surface of the nozzle 903 is fixedly connected to the outer wall of the gear shaft 8. The upper surface of the workbench 1 is fixedly connected with a hydraulic rod 10, the output end of the hydraulic rod 10 is fixedly connected with a fixed plate 11, the lower surface of the fixed plate 11 is fixedly connected with a slider 13, the interior of the workbench 1 is provided with a slide groove 12, the outer wall of the slider 13 is slidably connected to the interior of the slide groove 12, and the outer wall of the workbench 1 is slidably connected with a collection component 15. The collection component 15 includes a collection frame 1501, the outer wall of the collection frame 1501 is slidably connected to the outer wall of the workbench 1, the outer wall of the collection frame 1501 is fixedly connected with a slider 2 1502, the interior of the workbench 1 is provided with a slide groove 14, the outer wall of the slider 2 1502 is slidably connected to the interior of the slide groove 14, and the outer wall of the collection frame 1501 is fixedly connected with a handle 1503.

[0057] Specifically, firstly, the nano coating liquid is put into the storage box 901, and then the steel is placed on the upper surface of the workbench 1, and the hydraulic rod 10 is turned on. The hydraulic rod 10 pushes the fixed plate 11 to slide. When the fixed plate 11 slides, it will drive the slider 13 to slide inside the slide groove 12. The fixed plate 11 will push the steel to be fixed on the outer wall of the bracket 2. By stably clamping the steel, it can be ensured that the steel will not move or shake when the nano coating is applied, and the coating liquid can be evenly attached to the surface of the steel to avoid uneven coating thickness caused by the movement of the steel. Then turn on the motor 3, the motor 3 will drive the turntable 4 to rotate. When the turntable 4 rotates, it will drive the rotating tooth plate 6 to slide on the outer wall of the fixed shaft 15. When the rotating tooth plate 6 slides on the outer wall of the fixed shaft 15, its interior will rotate on the outer wall of the fixed shaft 2 7. When the rotating tooth plate 6 rotates, it will drive the gear shaft 8 to slide. When the gear shaft 8 slides, it will drive the spray head 903 to spray the steel clamped and fixed by the fixed plate 11 and the bracket 2. The motion trajectory of reciprocating spraying can ensure that the coating liquid is evenly covered on the surface of the steel. Multiple reciprocating motions can supplement the uneven coating area that may appear during coating, reduce the fluctuation of coating thickness, and ensure the uniformity of coating; and when the slider 13 slides inside the slide groove 12, the spray residue remaining inside the slide groove 12 will be pushed out to the inside of the collection frame 1501. Pulling the handle 1503 can take out the collection frame 1501 for cleaning. If the paint or spray material residues remaining in the spraying process are not cleaned in time, it may cause cross contamination and affect the quality of the next spraying. By cleaning in a timely manner, it is possible to ensure that the coating on different batches of steel is pure and free of impurities, improving the consistency and reliability of the final product.

[0058] Please refer to the attached Figure 1 As shown, the pretreatment process for cold-bent thin-walled steel production includes the following steps:

[0059] S1: Surface inspection and cleaning

[0060] Inspection: Use eddy current flaw detector or ultrasonic detector to conduct a comprehensive inspection of the steel surface to ensure there are no obvious defects such as cracks, bubbles, rust spots, etc.

[0061] Mechanical cleaning: Use sandblasting equipment to mechanically clean the steel surface. The sandblasting pressure is set to 0.3-0.6MPa, and 80-120 mesh abrasive is used. The cleaning time is 3-10 minutes to ensure that there is no oxide scale, rust and oil stain on the surface.

[0062] Chemical cleaning: After mechanical cleaning, use 2%-5% alkaline solution or 0.5%-1.0% acid solution to chemically clean the steel surface, the temperature is controlled at 30℃-50℃, and the cleaning time is 3-10 minutes. After cleaning, rinse with clean water to remove residual chemicals.

[0063] S2: Pickling

[0064] Pickling solution preparation: Use 10%-15% hydrochloric acid or sulfuric acid solution as the pickling solution. Choose the appropriate acid type according to the material of the steel.

[0065] Pickling process: Immerse the steel in the pickling tank, control the temperature at 50℃-60℃, and the pickling time is 5-15 minutes. The acid reacts with the oxide on the surface of the steel to remove the rust and oxide scale on the surface.

[0066] Rinsing: After pickling, immediately rinse the steel surface with clean water at 20℃-30℃ to ensure that there is no acid residue to prevent corrosion problems in subsequent processes.

[0067] S3: Nano coating pre-treatment process

[0068] Material preparation: Use nano-alumina (Al2O3) or nano-silane (such as γ-aminopropyltriethoxysilane, APTES) as the coating material to prepare a 1%-5% nano-coating liquid. Use deionized water or ethanol as the solvent and stir ultrasonically for 30 minutes to ensure that the nanoparticles are evenly dispersed.

[0069] Use spraying technology to evenly spray on the steel surface. The coating thickness is controlled between 10-50 nanometers.

[0070] Curing treatment: After coating, place the steel in a low temperature oven, set the temperature to 80℃-120℃, and bake for 10-15 minutes to cure the coating. After curing, cool and rinse the surface with deionized water, and finally air dry.

[0071] S4: Phosphate

[0072] Preparation of phosphating solution: Use 5% - 10% phosphoric acid solution as the phosphating solution, and control the temperature at 60℃ - 80℃.

[0073] Phosphating process: Immerse the steel in the phosphating solution for 10-20 minutes to form a uniform phosphate film (such as iron phosphate or zinc phosphate) on the surface to enhance the corrosion resistance and coating adhesion.

[0074] Passivation treatment: Passivation treatment is carried out immediately after phosphating, using 1%-3% chromate solution for surface passivation, and the treatment time is 5-10 minutes. After passivation, rinse with clean water to ensure the stability of the film layer.

[0075] S5: Micro-arc oxidation (MAO) pretreatment process

[0076] Electrolyte preparation: The electrolyte is prepared by mixing 5-10 g / L of sodium salt, 1-3 g / L of potassium salt, 10-20 g / L of silicate and 2-5 g / L of borate.

[0077] Micro-arc oxidation process: connect the steel as anode and the stainless steel plate as cathode, the power supply voltage is set to 300-600V, and the current density is 10-30A / dm 2 The treatment time is 5-20 minutes. Under the action of high-voltage pulse current, micro-arc discharge occurs on the surface of the steel, forming a 2-10 micron ceramic oxide film (such as Al2O3, SiO2).

[0078] Subsequent treatment: After micro-arc oxidation, the steel surface is cleaned with deionized water to remove residual electrolytes, and then naturally cooled in the air. If necessary, sealing treatment can be performed on the oxide film to further improve corrosion resistance.

[0079] S6: Plasma Surface Activation

[0080] Step description: Before oiling, use plasma surface treatment technology to activate the steel surface. Plasma treatment further improves the adhesion of the coating or plating by generating active groups on the steel surface.

[0081] Plasma Type: Uses oxygen or argon plasma.

[0082] Treatment process: The steel is placed in a plasma treatment chamber, and a radio frequency voltage (13.56MHz) is applied. The power is controlled at 50-300W, and the treatment time is 1-5 minutes.

[0083] Effect: Plasma treatment generates polar groups (such as hydroxyl or carbonyl) on the steel surface, which enhances the chemical bonding and mechanical adhesion of subsequent coatings or plating.

[0084] S7: Oiling

[0085] Anti-rust oil type: According to the application requirements of steel, choose light mineral oil or synthetic oil as anti-rust oil.

[0086] Oiling process: Use automatic oil spraying equipment to evenly coat the steel surface, and the coating thickness is controlled at 3-5 microns. After oiling, the steel should be left at room temperature for 10-15 minutes to ensure that the oil film is even and there is no leakage.

[0087] Effect inspection: Use a microscope to check the surface of the oiled steel to ensure that there is no obvious accumulation or shedding of oil film.

[0088] S8: Anti-fingerprint coating

[0089] Step description: After oiling, you can choose to add anti-fingerprint coating treatment to improve the stain resistance of the steel surface, which is especially suitable for products with high appearance requirements.

[0090] Materials: Anti-fingerprint coating materials are generally silicone resins or fluorine-containing polymers.

[0091] Coating process: Spray or dip coating to evenly coat the anti-fingerprint coating on the steel surface. The coating thickness is controlled between 1-3 microns.

[0092] Curing: After coating, cure at 150℃-200℃ for 10-20 minutes to ensure the hardness and adhesion of the coating.

[0093] Effect: Anti-fingerprint coating can reduce the contamination of steel surface by fingerprints, stains, etc., making the product easier to clean during use and maintaining its beauty.

[0094] The following is an introduction in conjunction with specific embodiments:

[0095] Example 1: Pretreatment process of high corrosion resistance cold-bent thin-walled steel

[0096] Application scenarios: Suitable for environments requiring extremely high corrosion resistance, such as marine engineering or chemical equipment.

[0097] Surface inspection and cleaning:

[0098] Sandblasting pressure: 0.5MPa, using 120 mesh abrasive.

[0099] Chemical cleaning: 3% alkaline solution, cleaning temperature 40°C, time 8 minutes.

[0100] Pickling:

[0101] Pickling solution: 15% hydrochloric acid solution.

[0102] Pickling temperature: 55°C, time: 12 minutes.

[0103] Nano coating pre-treatment process:

[0104] Material: Nano-alumina (Al2O3).

[0105] Coating thickness: 30 nm.

[0106] Baking temperature: 100°C, time: 12 minutes.

[0107] Phosphating:

[0108] Phosphating solution: 8% phosphoric acid solution.

[0109] Phosphating temperature: 70°C, time: 15 minutes.

[0110] Passivation solution: 2% chromate solution, passivation time 7 minutes.

[0111] Micro-arc oxidation (MAO) pretreatment process:

[0112] Electrolyte: Sodium silicate 10g / L, potassium salt 2g / L.

[0113] Voltage: 400V, current density 20A / dm 2 , time 15 minutes.

[0114] Oxide film thickness: 8 microns.

[0115] Plasma surface activation:

[0116] Argon plasma, power 150W, time 3 minutes.

[0117] Oiling:

[0118] Anti-rust oil type: light mineral oil.

[0119] Coating thickness: 4 microns.

[0120] Anti-fingerprint coating treatment:

[0121] Material: Silicone resin.

[0122] Coating thickness: 2 microns, curing temperature 180°C, time 15 minutes.

[0123] Example 2: Pretreatment process of high-strength wear-resistant cold-bent thin-walled steel

[0124] Application scenarios: Suitable for environments requiring high strength and wear resistance such as mechanical parts or tool manufacturing. Surface inspection and cleaning:

[0125] Sandblasting pressure: 0.6MPa, using 100 mesh abrasive.

[0126] Chemical cleaning: 5% alkaline solution, cleaning temperature 45°C, time 10 minutes.

[0127] Pickling:

[0128] Pickling solution: 12% sulfuric acid solution.

[0129] Pickling temperature: 60°C, time: 10 minutes.

[0130] Nano coating pre-treatment process:

[0131] Material: Nanosilane (APTES).

[0132] Coating thickness: 20 nm.

[0133] Baking temperature: 90℃, time: 10 minutes.

[0134] Phosphating:

[0135] Phosphating solution: 10% phosphoric acid solution.

[0136] Phosphating temperature: 75°C, time: 18 minutes.

[0137] Passivation solution: 3% chromate solution, passivation time 5 minutes.

[0138] Micro-arc oxidation (MAO) pretreatment process:

[0139] Electrolyte: silicate 15g / L, sodium salt 8g / L.

[0140] Voltage: 500V, current density 25A / dm 2 , time 10 minutes.

[0141] Oxide film thickness: 6 microns.

[0142] Plasma surface activation:

[0143] Oxygen plasma, power 200W, time 4 minutes.

[0144] Oiling:

[0145] Anti-rust oil type: heavy mineral oil.

[0146] Coating thickness: 5 microns.

[0147] Anti-fingerprint coating treatment:

[0148] Material: Fluoropolymer.

[0149] Coating thickness: 3 microns, curing temperature 200°C, time 20 minutes.

[0150] Example 3: Pretreatment process of cold-bent thin-walled steel with high surface finish

[0151] Application scenarios: Suitable for applications with extremely high requirements for surface finish, such as architectural decoration or automobile manufacturing. Surface inspection and cleaning:

[0152] Sandblasting pressure: 0.4MPa, using 150 mesh abrasive.

[0153] Chemical cleaning: 2% acid solution, cleaning temperature 35℃, time 5 minutes.

[0154] Pickling solution: 10% hydrochloric acid solution.

[0155] Pickling temperature: 50°C, time: 8 minutes.

[0156] Nano coating pre-treatment process:

[0157] Material: Nano-alumina (Al2O3).

[0158] Coating thickness: 10 nm.

[0159] Baking temperature: 80℃, time: 10 minutes.

[0160] Phosphating:

[0161] Phosphating solution: 7% phosphoric acid solution.

[0162] Phosphating temperature: 65°C, time: 12 minutes.

[0163] Passivation solution: 1% chromate solution, passivation time 5 minutes.

[0164] Micro-arc oxidation (MAO) pretreatment process:

[0165] Electrolyte: Sodium silicate 10g / L, potassium salt 1g / L.

[0166] Voltage: 300V, current density 15A / dm 2 , time 8 minutes.

[0167] Oxide film thickness: 4 microns.

[0168] Plasma surface activation:

[0169] Argon plasma, power 100 W, time 2 minutes.

[0170] Oiling:

[0171] Anti-rust oil type: Light synthetic oil.

[0172] Coating thickness: 3 microns.

[0173] Anti-fingerprint coating treatment:

[0174] Material: Silicone resin.

[0175] Coating thickness: 1 micron, curing temperature 160°C, time 15 minutes.

[0176] Example 4: Pretreatment process of cold-bent thin-walled steel with high adhesion coating

[0177] Application scenarios: Suitable for steel materials that require high adhesion in the coating process, such as automobile bodies or high-end home appliance housings.

[0178] Surface inspection and cleaning:

[0179] Sandblasting pressure: 0.45MPa, using 110 mesh abrasive.

[0180] Chemical cleaning: 4% alkaline solution, cleaning temperature 40°C, time 7 minutes.

[0181] Pickling:

[0182] Pickling solution: 14% sulfuric acid solution.

[0183] Pickling temperature: 55°C, time: 10 minutes.

[0184] Nano coating pre-treatment process:

[0185] Material: Nanosilane (APTES).

[0186] Coating thickness: 25 nm.

[0187] Baking temperature: 95°C, time: 12 minutes.

[0188] Phosphating:

[0189] Phosphating solution: 9% phosphoric acid solution.

[0190] Phosphating temperature: 70°C, time: 16 minutes.

[0191] Passivation solution: 2% chromate solution, passivation time 6 minutes.

[0192] Micro-arc oxidation (MAO) pretreatment process:

[0193] Electrolyte: silicate 12g / L, sodium salt 6g / L.

[0194] Voltage: 450V, current density 22A / dm 2 , time 12 minutes.

[0195] Oxide film thickness: 7 microns.

[0196] Plasma surface activation:

[0197] Oxygen plasma, power 180W, time 3 minutes.

[0198] Oiling:

[0199] Anti-rust oil type: light mineral oil.

[0200] Coating thickness: 4 microns.

[0201] Anti-fingerprint coating treatment:

[0202] Material: Fluoropolymer.

[0203] Coating thickness: 2 microns, curing temperature 190°C, time 18 minutes.

[0204] Table 1 The following is a comparison table of the final properties of cold-bent thin-walled steel after pretreatment in different embodiments

[0205]

[0206]

[0207] Among them, the table fields are explained as follows:

[0208] Corrosion resistance: refers to the ability of steel to resist corrosion in a corrosive environment (such as moisture, salt spray, acid and alkali, etc.). The higher the corrosion resistance, the longer the life of the steel when used in a harsh environment, and it is not easy to rust or corrode.

[0209] Wear resistance: refers to the ability of steel to resist wear under friction or mechanical stress. Steels with high wear resistance are suitable for use in high-friction, wear-prone environments, such as mechanical parts, tools and industrial equipment.

[0210] Surface finish: refers to the smoothness of the steel surface after treatment. Steel with high surface finish has a smooth and flawless surface and is suitable for occasions with high requirements for appearance, such as architectural decoration and automobile manufacturing.

[0211] Coating Adhesion: refers to the ability of the coating to adhere to the steel surface. A coating with strong adhesion is not easy to peel or fall off during use, which is very important in occasions where painting or protective coating is required.

[0212] Surface hardness: refers to the ability of the steel surface to resist indentation or scratching. Steel with high surface hardness is not easily scratched or deformed, and is suitable for use in environments with high hardness and high wear resistance requirements.

[0213] Anti-fingerprint performance: refers to the ability of steel surfaces to prevent the adhesion of contaminants such as fingerprints and oil. Surfaces with high anti-fingerprint performance are easy to clean and are suitable for products with high appearance requirements and frequent contact, such as high-end home appliances and automotive exteriors.

[0214] Coating durability: refers to the ability of a coating to maintain its function and appearance after prolonged use or exposure to harsh environments. A coating with high durability can still maintain its protective and aesthetic effects after long-term use.

[0215] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Cold-bent thin-walled steel production pretreatment device, characterized in that: The invention comprises a workbench (1), wherein the upper surface of the workbench (1) is fixedly connected to a spraying assembly (9), the upper surface of the workbench (1) is fixedly connected to a bracket (2), the right outer wall of the bracket (2) is fixedly connected to a motor (3), the output end of the motor (3) is fixedly connected to a turntable (4), the outer wall of the turntable (4) is fixedly connected to a fixed shaft 1 (5), the outer wall of the fixed shaft 1 (5) is slidably connected to a rotating tooth plate (6), the left outer wall of the bracket (2) is fixedly connected to a fixed shaft 2 (7), the interior of the rotating tooth plate (6) is rotatably connected to the outer wall of the fixed shaft 2 (7), the interior of the bracket (2) is slidably connected to a gear shaft (8), and the outer wall of the rotating tooth plate (6) is meshingly connected to the outer wall of the gear shaft (8).

2. The cold-bent thin-walled steel production pretreatment device according to claim 1 is characterized in that: The spraying assembly (9) comprises a storage box (901), the interior of which is fixedly connected to a pipe (902), an end of the pipe (902) away from the storage box (901) being fixedly connected to a spray head (903), and an upper surface of the spray head (903) being fixedly connected to an outer wall of the gear shaft (8).

3. The cold-bent thin-walled steel production pretreatment device according to claim 1 is characterized in that: The upper surface of the workbench (1) is fixedly connected to a hydraulic rod (10), the output end of the hydraulic rod (10) is fixedly connected to a fixed plate (11), the lower surface of the fixed plate (11) is fixedly connected to a sliding block (13), a sliding groove (12) is provided inside the workbench (1), the outer wall of the sliding block (13) is slidably connected to the inside of the sliding groove (12), and the outer wall of the workbench (1) is slidably connected to a collecting assembly (15).

4. The cold-bent thin-walled steel production pretreatment device according to claim 3 is characterized in that: The collecting component (15) comprises a collecting frame (1501), the outer wall of the collecting frame (1501) is slidably connected to the outer wall of the working table (1), the outer wall of the collecting frame (1501) is fixedly connected to a second slider (1502), a sliding groove (14) is provided inside the working table (1), the outer wall of the second slider (1502) is slidably connected to the inside of the sliding groove (14), and the outer wall of the collecting frame (1501) is fixedly connected to a handle (1503).

5. Cold-bent thin-walled steel production pretreatment process, characterized in that: The cold-bent thin-walled steel production pretreatment device according to any one of claims 1 to 4 comprises the following steps: S1: Surface inspection and cleaning First, use the detection equipment to check the steel surface to determine whether there are cracks, bubbles, rust spots on the surface. Then, mechanical sandblasting and chemical cleaning are used to remove the oxide scale, rust spots and oil stains on the steel surface. S2: Pickling Immerse the steel in a pickling tank and use hydrochloric acid or sulfuric acid solution to remove oxides and rust on the steel surface. After pickling, rinse the steel thoroughly with clean water; S3: Nano coating pre-treatment process A layer of nano-scale oxide or silane coating is applied on the surface of the pickled steel, and the nano-coating liquid is evenly distributed on the surface of the steel by spraying. After coating, it is cured by low-temperature baking to form an ultra-thin nano-coating; S4: Phosphate The steel is immersed in the phosphating solution to form a phosphate film on the surface. After phosphating, the steel is passivated. After the treatment is completed, it is rinsed with clean water again; S5: Micro-arc oxidation pretreatment process The steel is placed in an electrolyte containing sodium salt, potassium salt, silicate and borate, and a high-voltage pulse current is applied to generate micro-arc discharge on the surface of the steel to form a ceramic oxide film. After oxidation, the steel is cooled and cleaned; S6: Plasma Surface Activation Before oiling, the steel surface is treated with oxygen or argon plasma. Plasma treatment activates chemical groups on the steel surface. S7: Oiling After the surface treatment is completed, a layer of anti-rust oil is evenly applied to the surface of the steel. The anti-rust oil is evenly applied on the surface of the steel through automatic oil spraying equipment. After oiling, the steel is left to stand for a period of time; S8: Anti-fingerprint coating Using silicone resin or fluorine-containing polymer, an anti-fingerprint coating is formed on the surface of the steel by spraying or dipping, and then the steel is cured to form a surface protection layer.

6. The cold-bent thin-walled steel production pretreatment process according to claim 5, characterized in that: In the step S1, an eddy current flaw detector or an ultrasonic detector is used to conduct a comprehensive inspection of the steel surface; Then use sandblasting equipment to mechanically clean the steel surface, the sandblasting pressure is set to 0.3-0.6MPa, and 80-120 mesh abrasive is used; After mechanical cleaning, use 2%-5% alkaline solution or 0.5%-1.0% acidic solution to chemically clean the steel surface. The temperature is controlled at 30℃-50℃ and the cleaning time is 3-10 minutes. After cleaning, rinse with clean water to remove residual chemicals.

7. The cold-bent thin-walled steel production pretreatment process according to claim 5, characterized in that: In the step S2, 10%-15% hydrochloric acid or sulfuric acid solution is used as the pickling liquid; Immerse the steel in the pickling tank, control the temperature at 50℃-60℃, and the pickling time is 5-15 minutes; After pickling, immediately rinse the steel surface with clean water at 20℃-30℃.

8. The cold-bent thin-walled steel production pretreatment process according to claim 5, characterized in that: In the step S3, nano-alumina or nano-silane is prepared into a 1%-5% nano-coating liquid, deionized water or ethanol is used as a solvent, ultrasonically stirred for 30 minutes, and then placed in a storage box (901); Then, the steel is placed on the upper surface of the workbench (1), and the hydraulic rod (10) is turned on. The hydraulic rod (10) pushes the fixed plate (11) to slide. When the fixed plate (11) slides, it drives the slider 1 (13) to slide inside the slide groove 1 (12). The fixed plate (11) pushes the steel to be fixed on the outer wall of the bracket (2). Then, the motor (3) is turned on. The motor (3) drives the turntable (4) to rotate. When the turntable (4) rotates, it drives the rotating gear plate (6) to slide on the outer wall of the fixed shaft 1 (5). When the rotating gear plate (6) slides on the outer wall of the fixed shaft 1 (5), its inside rotates on the outer wall of the fixed shaft 2 (7). When the rotating gear plate (6) rotates, it drives the gear shaft (8) to slide. When the gear shaft (8) slides, it drives the spray head (903) to spray the steel clamped and fixed by the fixed plate (11) and the bracket (2). The coating thickness is controlled between 10 and 50 nanometers. After coating, take out the steel and put it into a low-temperature oven with the temperature set at 80℃-120℃ for 10-15 minutes to cure the coating. After curing, cool it and rinse the surface with deionized water, and finally air dry it.

9. The cold-bent thin-walled steel production pretreatment process according to claim 5, characterized in that: In the step S4, a 5%-10% phosphoric acid solution is used as the phosphating solution, the temperature is controlled at 60°C-80°C, the steel is immersed in the phosphating solution for 10-20 minutes, and a passivation treatment is performed immediately after phosphating, using a 1%-3% chromate solution for surface passivation for 5-10 minutes, and rinsed with clean water after passivation.

10. The cold-bent thin-walled steel production pretreatment process according to claim 5, characterized in that: In the step S5, the electrolyte is prepared by mixing 5-10 g / L of sodium salt, 1-3 g / L of potassium salt, 10-20 g / L of silicate and 2-5 g / L of borate, the steel is connected as the anode, the stainless steel plate is used as the cathode, the power supply voltage is set to 300-600 V, and the current density is 10-30 A / dm 2 The treatment time is 5-20 minutes. Under the action of high-voltage pulse current, micro-arc discharge occurs on the steel surface, forming a 2-10 micron ceramic oxide film. After micro-arc oxidation, the steel surface was cleaned with deionized water to remove residual electrolyte, and then naturally cooled in air; In the step S6, the steel is placed in a plasma treatment chamber, a radio frequency voltage of 13.56 MHz is applied, the power is controlled at 50-300 W, and the treatment time is 1-5 minutes; In the step S7, light mineral oil or synthetic oil is selected as the rust-proof oil; Use automatic oil spraying equipment to evenly coat the steel surface, and the coating thickness is controlled at 3-5 microns. After oiling, the steel is left to stand at room temperature for 10-15 minutes; In the step S8, the anti-fingerprint coating material includes silicone resin or fluorine-containing polymer, and the coating thickness is controlled between 1-3 microns. After coating, it is cured at 150° C.-200° C. for 10-20 minutes.

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