Bulletproof steel laser shock and micro-arc oxidation composite processing method

Abstract

The application discloses a kind of bulletproof steel laser impact and micro-arc oxidation composite processing method, steps: 1) the rust of bulletproof steel is pickled and removed;2) after the rust of bulletproof steel is pickled and removed, it is washed clean with tap water and is carried out first micro-arc oxidation treatment within 3-5min;3) washing and drying;4) first laser impact;5) second micro-arc oxidation treatment: 6) washing and drying;7) second laser impact.The application effectively combines laser impact treatment with micro-arc oxidation, adopts twice micro-arc oxidation and twice laser impact, not only effectively removes rust layer, surface forms compressive stress layer and dense micro-arc oxidation film layer, but also effectively improves the corrosion resistance and mechanical properties of steel plate.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology and relates to a composite treatment method of laser shock and micro-arc oxidation for bulletproof steel, used for rust removal of NP series bulletproof steel. Background Technology

[0002] With industrial development, Chinese manufacturing has made leaps and bounds, and domestically produced bulletproof steel plates have also developed rapidly. Their protective performance is no worse than imported bulletproof steel plates, and in some specific aspects, they are even superior. The NP series bulletproof steel developed by Nanjing Iron & Steel Co., Ltd. is a leader among domestically produced bulletproof steel plates. The NP series bulletproof steel offers superior protection against various bullet impacts, primarily against Type 95 steel-core bullets. Nanjing Iron & Steel's NP450, NP500, and NP550 series bulletproof steel plates exhibit superior resistance to Type 95 steel-core bullets, strong resistance to destructive impacts, uniform and stable performance, and good plate shape and surface quality. However, the NP series bulletproof steel is highly susceptible to rust, which affects its performance during subsequent processing and use.

[0003] After steel plates rust, they are usually removed by grinding. However, bulletproof steel has high strength and hardness, making grinding difficult. Currently, the use of rust removers cannot reduce the impact of rust on the performance of steel plates.

[0004] Therefore, it is necessary to develop a new method for rust removal and rust prevention of bulletproof steel, which can not only effectively remove the rust layer, but also improve the corrosion resistance and mechanical properties of the steel plate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a composite treatment method of laser shock and micro-arc oxidation for bulletproof steel, which can not only effectively remove the rust layer, but also improve the corrosion resistance and mechanical properties of the steel plate.

[0006] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a method for combined laser shock and micro-arc oxidation treatment of bulletproof steel, characterized by including the following steps:

[0007] 1) Pickling and rust removal of bulletproof steel; because NP series bulletproof steel is extremely prone to rusting, pickling is necessary;

[0008] 2) After the bulletproof steel has been pickled and rusted, rinse it with tap water and then perform the first micro-arc oxidation treatment within 3 to 5 minutes; this is because bulletproof steel is very easy to rust when exposed to water, so the time should not be too long.

[0009] 3) Washing and drying;

[0010] 4) First laser shock: In order to improve the surface properties of the steel plate, reduce the depth of rust pits, and compress the micro-arc oxide film layer to better integrate it with the steel plate;

[0011] 5) Second micro-arc oxidation treatment:

[0012] 6) Washing and drying;

[0013] 7) Second laser shock: In order to make the micro-arc oxide film layer denser and the compressive stress layer of the metal substrate harder, thereby improving the corrosion resistance and hardness of the steel plate, two laser shocks are performed to obtain better results.

[0014] Furthermore, the specific process of pickling and rust removal in step 1) is as follows: prepare a 5-8 mol / L ammonium chloride aqueous solution, spray the solution evenly onto the bulletproof steel plate and soak for 10-15 minutes, rinse it clean, continue to spray the ammonium chloride solution onto the bulletproof steel plate and soak for 10-15 minutes, repeat this process until the rust is clean.

[0015] Furthermore, the electrical parameters of the first micro-arc oxidation treatment in step 2) are: positive voltage 700-850V, negative voltage 300-500V, frequency 1500-3500Hz, positive and negative duty cycle 5-30%, and waveform is sinusoidal.

[0016] Electrolyte: Na2AlO2 20~40g / L, Na2CO3 1~5g / L, Na2SiO3 5~15g / L, NaH2PO2 5~15g / L, Al2O3 nanoparticles (5~25nm) 5~10g / L, Na2WO4 3~10g / L, NaOH 1~5g / L;

[0017] During the micro-arc oxidation process, the electrolyte temperature is maintained at 25–50℃, and the oxidation time is 5–10 min.

[0018] Furthermore, in steps 3) and 6), the washing and drying process involves washing the micro-arc oxidized steel plate with alcohol and then drying it with a warm air blower.

[0019] Furthermore, the process parameters for the first laser shock in step 4) are: 15–25 GW / cm². 2 A light spot with a diameter of 1–4 mm and an overlap rate of 30–50%.

[0020] Furthermore, the electrical parameters of the second micro-arc oxidation treatment in step 5) are: positive voltage 700-850V, negative voltage 300-500V, frequency 1500-3500Hz, positive and negative duty cycle 5-30%, and waveform is sinusoidal.

[0021] Electrolyte: Na2AlO2 10~20g / L, Na2SiO3 5~15g / L, NaH2PO2 5~15g / L, Al2O3 nanoparticles (5~25nm) 1~5g / L, TiO2 particles 1~5g / L, Na2WO4 3~10g / L, NaOH 1~5g / L;

[0022] During the micro-arc oxidation process, the electrolyte temperature is maintained at 25–50℃, and the oxidation time is 30–50 min, resulting in a relatively thick micro-arc oxidation film.

[0023] Finally, the process parameters for the second laser shock in step 7) are: 15-25 GW / cm². 2 A light spot with a diameter of 4-6 mm and an overlap rate of 50-60%.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] 1) This invention breaks through the micro-arc oxidation film technology of steel, and gradually improves the quality of the film and enhances its corrosion resistance by using two micro-arc oxidation processes.

[0026] 2) The effective combination of laser shock treatment and micro-arc oxidation not only improves the mechanical properties and corrosion resistance of the metal substrate, but also enhances the density of the micro-arc oxidation film.

[0027] The process of this invention is scientific, reasonable, and easy to operate. It can not only effectively remove the rust layer and form a compressive stress layer and a dense micro-arc oxide film layer on the surface, but also effectively improve the corrosion resistance and mechanical properties of the steel plate. It can be used for rust removal of NP series bulletproof steel. Attached Figure Description

[0028] Figure 1 This is a process flow diagram provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the rust layer on the bulletproof steel plate before treatment provided by the present invention;

[0030] Figure 3 This is a schematic diagram of the metal cross-section of the bulletproof steel plate after rust removal treatment provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the film structure of the bulletproof steel plate provided by the present invention after micro-arc oxidation. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Example 1

[0034] Process flow as follows Figure 1 As shown, Figure 2 This is a schematic diagram of the rust layer on the bulletproof steel plate before treatment.

[0035] 1) Acid pickling for rust removal. Prepare a 5 mol / L ammonium chloride aqueous solution. Spray the solution evenly onto the bulletproof steel plate and soak for 10 minutes. Rinse thoroughly. Continue spraying the ammonium chloride solution onto the bulletproof steel plate and soaking for 10 minutes. Repeat this process until the rust is completely removed. A schematic diagram of the metal cross-section after rust removal treatment of the bulletproof steel plate is shown below. Figure 3 As shown.

[0036] 2) First micro-arc oxidation treatment. After pickling, rinse thoroughly with tap water and proceed to the next step for micro-arc oxidation within 3 minutes.

[0037] Electrical parameters of micro-arc oxidation treatment:

[0038] Positive voltage 700V, negative voltage 300V, frequency 1500Hz, positive and negative duty cycle 5%, waveform is sinusoidal.

[0039] Electrolyte for micro-arc oxidation treatment:

[0040] Na2AlO2 20g / L, Na2SiO3 5g / L, Na2CO3 1g / L, NaH2PO2 5g / L, Al2O3 nanoparticles (5~25nm) 5g / L, Na2WO4 3g / L, NaOH 1g / L.

[0041] During the micro-arc oxidation process, the electrolyte temperature is maintained at 25–30°C, and the oxidation time is 5 min.

[0042] 3) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0043] 4) First laser shock. Parameters are as follows:

[0044] 15GW / cm 2 A 1mm diameter light spot with a 30% overlap rate.

[0045] 5) Second micro-arc oxidation treatment. Electrical parameters of the micro-arc oxidation treatment:

[0046] Positive voltage 700V, negative voltage 300V, frequency 1500Hz, positive and negative duty cycle 5%, waveform is sine;

[0047] Electrolyte for micro-arc oxidation treatment:

[0048] Na2AlO2 10g / L, Na2SiO3 5g / L, NaH2PO2 5g / L, Al2O3 nanoparticles (5~25nm) 1g / L, TiO2 particles 1g / L, Na2WO4 3g / L, NaOH 1g / L;

[0049] During the micro-arc oxidation process, the electrolyte temperature is maintained at 25–30°C, and the oxidation time is 30 minutes. A schematic diagram of the film structure of the bulletproof steel plate after micro-arc oxidation is shown below. Figure 4 As shown.

[0050] 6) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0051] 7) Second laser shock. The process parameters for the second laser shock are as follows:

[0052] 15GW / cm 2 4mm diameter light spot, 50% overlap rate.

[0053] Example 2

[0054] 1) Pickling to remove rust. Prepare a 5-8 mol / L ammonium chloride aqueous solution, spray the solution evenly onto the bulletproof steel plate and soak for 12 minutes, rinse clean, continue to spray the ammonium chloride solution onto the bulletproof steel plate and soak for 12 minutes, repeat this process until the rust is completely removed.

[0055] 2) First micro-arc oxidation treatment. After pickling, rinse thoroughly with tap water and proceed to the next step for micro-arc oxidation within 4 minutes.

[0056] Electrical parameters of micro-arc oxidation treatment:

[0057] Positive voltage 800V, negative voltage 400V, frequency 2500Hz, positive and negative duty cycle 20%, waveform is sinusoidal.

[0058] Electrolyte for micro-arc oxidation treatment:

[0059] Na2AlO2 30g / L, Na2SiO3 10g / L, Na2CO3 3g / L, NaH2PO2 10g / L, Al2O3 nanoparticles (5~25nm) 7g / L, Na2WO4 7g / L, NaOH 3g / L.

[0060] During the micro-arc oxidation process, the electrolyte temperature is maintained at 30–40°C, and the oxidation time is 8 min.

[0061] 3) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0062] 4) First laser shock. The first laser shock treatment is performed with the following parameters:

[0063] 20GW / cm 2 2mm diameter light spot, 40% overlap rate.

[0064] 5) Second micro-arc oxidation treatment. Electrical parameters of the micro-arc oxidation treatment:

[0065] Positive voltage 800V, negative voltage 400V, frequency 2500Hz, positive and negative duty cycle 20%, waveform is sine;

[0066] Electrolyte for micro-arc oxidation treatment:

[0067] Na2AlO2 15g / L, Na2SiO3 10g / L, NaH2PO2 10g / L, Al2O3 nanoparticles (5~25nm) 3g / L, TiO2 particles 3g / L, Na2WO4 7g / L, NaOH 3g / L;

[0068] During the micro-arc oxidation process, the electrolyte temperature is maintained at 30–40°C, and the oxidation time is 40 min.

[0069] 6) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0070] 7) Second laser shock. A second laser shock is performed with the following parameters:

[0071] 20GW / cm 2 A 5mm diameter light spot with a 55% overlap rate.

[0072] Example 3

[0073] 1) Pickling to remove rust. Prepare an 8 mol / L ammonium chloride aqueous solution, spray the solution evenly onto the bulletproof steel plate and soak for 15 minutes, rinse clean, continue to spray the ammonium chloride solution onto the bulletproof steel plate and soak for 15 minutes, repeat this process until the rust is completely removed.

[0074] 2) First micro-arc oxidation treatment. After pickling, rinse thoroughly with tap water and proceed to the next step for micro-arc oxidation within 5 minutes.

[0075] Electrical parameters of micro-arc oxidation treatment:

[0076] Positive voltage 850V, negative voltage 500V, frequency 3500Hz, positive and negative duty cycle 30%, waveform is sinusoidal;

[0077] Electrolyte for micro-arc oxidation treatment:

[0078] Na2AlO2 40g / L, Na2SiO3 15g / L, Na2CO3 5g / L, NaH2PO2 15g / L, Al2O3 nanoparticles (5~25nm) 10g / L, Na2WO4 10g / L, NaOH 5g / L;

[0079] During the micro-arc oxidation process, the electrolyte temperature is maintained at 40–50 °C, and the oxidation time is 10 min.

[0080] 3) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0081] 4) First laser shock. This step involves a first laser shock treatment with the following parameters:

[0082] 25GW / cm 2 4mm diameter light spot, 50% overlap rate.

[0083] 5) Second micro-arc oxidation treatment. Electrical parameters of the micro-arc oxidation treatment:

[0084] Positive voltage 850V, negative voltage 500V, frequency 3500Hz, positive and negative duty cycle 30%, waveform is sinusoidal.

[0085] Electrolyte for micro-arc oxidation treatment:

[0086] Na2AlO2 20g / L, Na2SiO3 15g / L, NaH2PO2 15g / L, Al2O3 nanoparticles (5~25nm) 5g / L, TiO2 particles 5g / L, Na2WO4 10g / L, NaOH 5g / L.

[0087] During the micro-arc oxidation process, the electrolyte temperature is maintained at 40–50 °C, and the oxidation time is 40 min.

[0088] 6) Washing and drying. The steel plate after micro-arc oxidation is washed with alcohol and then dried with a warm air blower.

[0089] 7) Second laser shock. A second laser shock is performed with the following parameters:

[0090] 25GW / cm 2 A 6mm diameter light spot with a 60% overlap rate.

[0091] Comparative Example 1

[0092] The steel plate was mechanically polished to produce a metallic luster and then sampled.

[0093] Comparative Example 2

[0094] After the steel plate is mechanically polished to a metallic luster, it is sampled after two laser impacts.

[0095] The parameters for the first laser shock are as follows:

[0096] 25GW / cm 2 4mm diameter light spot, 50% overlap rate.

[0097] The parameters for the second laser shock are as follows:

[0098] 25GW / cm 2 A 6mm diameter light spot with a 60% overlap rate.

[0099] Comparative Example 3

[0100] After removing rust from the steel plate with ammonium chloride, it was subjected to two micro-arc oxidation processes before sampling.

[0101] First step: Electrical parameters of micro-arc oxidation treatment:

[0102] Positive voltage 850V, negative voltage 500V, frequency 3500Hz, positive and negative duty cycle 30%, waveform is sinusoidal.

[0103] Electrolyte for micro-arc oxidation treatment:

[0104] Na2AlO2 40g / L, Na2SiO3 15g / L, Na2CO3 5g / L, NaH2PO2 15g / L, Al2O3 nanoparticles (5~25nm) 10g / L, Na2WO4 10g / L, NaOH 5g / L.

[0105] During the micro-arc oxidation process, the electrolyte temperature is maintained at 40–50 °C, and the oxidation time is 10 min.

[0106] Second: Electrical parameters of micro-arc oxidation treatment:

[0107] Positive voltage 850V, negative voltage 500V, frequency 3500Hz, positive and negative duty cycle 30%, waveform is sinusoidal.

[0108] Electrolyte for micro-arc oxidation treatment:

[0109] Na2AlO2 20g / L, Na2SiO3 15g / L, NaH2PO2 15g / L, Al2O3 nanoparticles (5~25nm) 5g / L, TiO2 particles 5g / L, Na2WO4 10g / L, NaOH 5g / L.

[0110] During the micro-arc oxidation process, the electrolyte temperature is maintained at 40–50°C, and the oxidation time is 50 min.

[0111] The comparative examples and embodiments described above are then tested and analyzed:

[0112] The salt spray test was conducted using an S-ICIA type salt spray corrosion chamber, following the GB10125-1997 standard "Artificial Atmosphere Corrosion Test - Salt Spray Test". A 50 g / L NaCl solution with a pH of 6.5–7.2 was used, adjusted with HCl or dilute NaHCO3 solution. The test temperature was (35±2)℃. An HR-150A Brinell hardness tester was used. A 10 mm diameter hardened steel ball was pressed into the material surface with 3000 kg of pressure and held for a period of time. After unloading, the ratio of the load to the indentation area was calculated. Three measurements were taken each time, and the average value was used as the Brinell hardness value (HB). The test results are shown in Table 1.

[0113] Table 1. Test Results of Comparative Examples and Embodiments

[0114] 1 Comparative Example 1 1 520 2 Comparative Example 2 4 541 3 Comparative Example 3 96 518 4 Example 1 144 538 5 Example 2 168 531 6 Example 3 144 536

[0115] As can be seen from Table 1, samples 2 through 6, after treatment, showed improved corrosion resistance and hardness compared to sample 1, which was not treated. Examples 1 through 3 showed significantly improved corrosion resistance and hardness, with the highest corrosion resistance reaching 168 hours and a hardness of 538 HB. Comparative Examples 2 and 3 show that samples that did not combine micro-arc oxidation with laser shock did not achieve the desired results. While Comparative Example 2 showed a significant increase in hardness, its corrosion resistance remained relatively poor, and although Comparative Example 3 showed improved corrosion resistance, its hardness decreased slightly.

[0116] Conclusion: Combining laser shock blasting with micro-arc oxidation treatment can not only effectively remove the rust layer and form a compressive stress layer and a dense micro-arc oxidation film on the surface, but also effectively improve the corrosion resistance and mechanical properties of steel plates.

Claims

1. A method for laser shock and micro-arc oxidation composite treatment of NP series bulletproof steel, characterized in that... Includes the following steps: 1) Pickling and rust removal are performed on the bulletproof steel; 2) After the bulletproof steel has been pickled and rust-removed, rinse it with water and then perform the first micro-arc oxidation treatment within 3-5 minutes; The electrical parameters for the first micro-arc oxidation treatment in step 2) are: positive voltage 700~850V, negative voltage 300~500V, frequency 1500~3500Hz, positive and negative duty cycle 5~30%, and waveform is sinusoidal. Electrolyte for the first micro-arc oxidation process: NaAlO2 20~40g / L, Na2CO3 1~5g / L, Na2SiO3 5~15g / L, NaH2PO2 5~15g / L, Al2O3 nanoparticles of 5~25nm 5~10g / L, Na2WO4 3~10g / L, NaOH 1~5g / L; During the first micro-arc oxidation process, the electrolyte temperature was maintained at 25~50℃, and the oxidation time was 5~10min; 3) Washing and drying; 4) the first laser impact; the process parameters of the first laser impact are: 15~25 GW / cm 2 , diameter 1~4 mm spot, 30~50% overlap rate; 5) Second micro-arc oxidation treatment; The electrical parameters for the second micro-arc oxidation treatment in step 5) are: positive voltage 700~850V, negative voltage 300~500V, frequency 1500~3500Hz, positive and negative duty cycle 5~30%, and waveform is sinusoidal. Electrolyte for the second micro-arc oxidation process: NaAlO2 10~20g / L, Na2SiO3 5~15g / L, NaH2PO2 5~15g / L, Al2O3 nanoparticles (5~25nm) 1~5g / L, TiO2 particles 1~5g / L, Na2WO4 3~10g / L, NaOH 1~5g / L; During the second micro-arc oxidation process, the electrolyte temperature was maintained at 25~50℃, and the oxidation time was 30~50min. 6) Washing and drying; 7) Second laser shock; the process parameters for the second laser shock are: 15~25 GW / cm 2 A light spot with a diameter of 4-6 mm and an overlap rate of 50-60%.

2. The method for combined laser shock and micro-arc oxidation treatment of NP series bulletproof steel according to claim 1, characterized in that: The specific process for pickling and rust removal in step 1) is as follows: Prepare an ammonium chloride aqueous solution of 5-8 mol / L, spray the solution evenly onto the bulletproof steel plate and soak for 10-15 minutes, rinse it clean, continue to spray the ammonium chloride solution onto the bulletproof steel plate and soak for 10-15 minutes, repeat this process until the rust is clean.

3. The method for combined laser shock and micro-arc oxidation treatment of NP series bulletproof steel according to claim 1, characterized in that: The washing and drying in steps 3) and 6) involves washing the micro-arc oxidized steel plate with alcohol and then drying it with a warm air blower.

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