A method for preparing ultra-thin precision stainless steel strip

Abstract

This invention discloses a method for preparing ultra-thin precision stainless steel strip, comprising the following processes: (1) First rolling: rolling the steel strip continuously for 9 to 12 passes; (2) First annealing: annealing at 800 to 880°C; (3) Second rolling: rolling continuously for 4 to 6 passes; (4) Second annealing: annealing at 1050 to 1120°C; (5) Tension straightening: straightening with an elongation of 0.3 to 0.7% and a tension of 700 to 800 N / mm²; (6) Heat treatment: annealing at 500 to 550°C to obtain heat-treated steel strip. This invention obtains ultra-thin steel strips with flat surfaces and improved mechanical properties and appearance through multiple continuous rolling, annealing, and heat treatment processes. Furthermore, a spinel coating is applied to the surface of the steel strip through silicon deposition, oxidation, coating, and high-temperature sintering processes, followed by electroplating to form a nickel plating layer. This results in finished stainless steel strips that not only have improved tensile strength and hardness but also excellent wear and corrosion resistance, making them suitable for a variety of applications.

Description

Technical Field

[0001] This invention relates to the field of ultra-thin steel strip technology, specifically to a method for preparing ultra-thin precision stainless steel strip. Background Technology

[0002] Precision stainless steel strip is widely used in aerospace, electronics, construction and decoration, petrochemicals, environmental protection equipment, precision instruments, and other fields, and is an indispensable key material for national economic construction and defense. Stainless steel has a wide variety of alloying elements in high concentrations, resulting in high resistance to deformation. Rolling is difficult, and the control of width, thickness, surface quality, and microstructure during strip forming is mutually restrictive and difficult to coordinate. With the development of technology, various products are moving towards thinner, lighter, and higher-performance designs, leading to an increasingly strong demand for new materials. Therefore, we propose a method for preparing ultra-thin precision stainless steel strip. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing ultra-thin precision stainless steel strips to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing ultra-thin precision stainless steel strip, comprising the following processes:

[0005] (1) One-time rolling: Take steel strips with a thickness of 0.34 to 0.48 mm and roll them in 9 to 12 passes;

[0006] (2) Single annealing: Annealing in a hydrogen atmosphere at a temperature of 800-880℃, with an annealing rate of 8-15m / min;

[0007] (3) Secondary rolling: 4 to 6 rolling passes are performed;

[0008] (4) Secondary annealing: Annealing in a hydrogen atmosphere at a temperature of 1050-1120℃ and an annealing rate of 10-15m / min;

[0009] (5) Straightening treatment: Straighten with an elongation of 0.3-0.7% and a tension of 700-800 N / mm²;

[0010] (6) Heat treatment: Annealing at 500-550°C in a hydrogen atmosphere to obtain heat-treated steel strip.

[0011] Furthermore, the steel strip is made of 316 stainless steel with a plate difference of less than 1%.

[0012] Furthermore, the (1) single rolling process is as follows: the total deformation is controlled at 50-80%; the rolling force is 150-400KN, the rolling tension is 5-60KN, and the rolling speed is 80-150m / min.

[0013] Furthermore, the secondary rolling process (3) is as follows: the total deformation is controlled at 60-70%; the rolling force is 100-350KN, the rolling tension is 5-50KN, and the rolling speed is 60-120m / min.

[0014] Furthermore, after the first annealing (2) and the second annealing (4), the stainless steel strip is cooled to room temperature in a hydrogen atmosphere and degreased and cleaned in water at 60-80°C at a cleaning speed of 60-100 m / min; then dried with nitrogen.

[0015] Furthermore, the unevenness of the stainless steel strip after the (5) tension straightening treatment is less than 0.25 mm / m.

[0016] Furthermore, the heat treatment process (6) is as follows: annealing speed 18-25 m / min, tension 85-150 N / mm²;

[0017] Furthermore, after heat treatment, the (6) gas is cooled in a hydrogen atmosphere, with the dew point of the hydrogen controlled at -70 to -50°C and the oxygen content controlled at 10 to 50 ppm.

[0018] Furthermore, the hydrogen atmosphere comprises 95-100% hydrogen by volume, with the remainder being nitrogen.

[0019] In the above technical solution, the raw steel strip is gradually rolled to an ultra-thin steel strip of 0.02-0.05 mm (thickness deviation ±0.005 mm) by two cold rolling processes, namely 9-12 passes and 4-6 passes. The surface roughness Ra of the rolling work rolls is 0.15-0.6 μm, decreasing with the rolling sequence. The surface roughness Ra of the first three rolling work rolls in the first rolling process is 0.5-0.6 μm, and the surface roughness Ra of the remaining rolling work rolls is 0.3-0.4 μm. The surface roughness Ra of the first rolling work roll in the second rolling process is 0.3-0.4 μm, and the surface roughness Ra of the remaining rolling work rolls is 0.15-0.2 μm. This reduces the steel strip thickness while ensuring that the heat-treated steel strip has a low surface roughness. Maintaining tension on the stainless steel strip during heat treatment can uniformly distribute internal stress, eliminate the negative effects of internal stress, and ensure the flatness of the stainless steel sheet surface, which helps improve the mechanical properties and appearance of the produced stainless steel strip. Controlling the hydrogen atmosphere can prevent oxidation of the stainless steel strip.

[0020] Furthermore, the surface of the heat-treated steel strip is provided with a spinel coating and a nickel plating.

[0021] Furthermore, the spinel coating is obtained by the following process:

[0022] (1) Silicon deposition: The heat-treated steel strip is placed in acetone, ultrasonically cleaned for 15-20 minutes to remove oil, washed with ethanol, and dried with nitrogen.

[0023] Place it in a deposition furnace, evacuate to 10-20 Pa, heat to 450-550℃, introduce a silicon infiltration source, and deposit for 15-25 min; remove it and sinter at 1000-1100℃ for 60 min to obtain silicon-infiltrated steel;

[0024] Furthermore, the silicon infiltration source includes silicon tetrahydrode and argon, with argon accounting for 90% of the volume.

[0025] (2) Oxidation: Take chromium powder and chromium oxide, place them in a sealed device with silicon-impregnated steel, and evacuate to 10-20 Pa; place them at 700-800℃ for heat treatment for 5.0-5.8 h to generate silicon oxide and obtain anodized steel strip;

[0026] Furthermore, the mass ratio of chromium powder to chromium oxide is (0.5–1.2):1; the average particle size is 68–80 μm;

[0027] (3) Coating: Mix magnesium oxide, aluminum oxide and deionized water at 3-7℃ to prepare a coating solution with a mass concentration of 12-13%; keep the environment at 3-7℃ and immerse the steel oxide strip for 9-10 seconds; take it out and dry it at 280-320℃ for 2-5 minutes.

[0028] In a nitrogen atmosphere, the temperature is raised to 700–720°C and held for 2 hours; then the temperature is raised to 900–920°C at a rate of 16–18°C / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1170–1200°C and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

[0029] Furthermore, both magnesium oxide and aluminum oxide are spherical with a particle size of 50–120 nm; the mass ratio of magnesium oxide to aluminum oxide is 1:(1.5–3.0).

[0030] In the above technical solution, silicon is deposited on the surface of the heat-treated steel strip using vapor deposition, and the surface composition is homogenized and internal stress is eliminated by high-temperature annealing. Silicon forms an intermetallic compound with iron and can strengthen the cementite on the surface of the heat-treated steel strip, thereby improving the strength and oxidation resistance of the steel strip. Argon is used as a protective atmosphere to maintain a high density on the surface of the steel strip and reduce surface voids.

[0031] Utilizing the oxygen potential difference between elements chromium, iron, and silicon, chromium and chromium oxide are used to oxidize the silicon on the surface of silicon-diffused steel, generating silicon dioxide. A layer of magnesium oxide and aluminum nitride is then deposited on the surface of the silicon dioxide. At high temperature, the magnesium oxide reacts with the silicon dioxide on the steel strip surface to obtain magnesium silicate, and aluminum ions diffuse, transforming it into magnesium aluminum spinel. The presence of silicon dioxide promotes the sintering of spinel, which helps to reduce the specific surface area of ​​spinel and the porosity of the steel strip surface, thereby improving the surface strength and wear resistance of the coated steel strip. Among these methods, spherical magnesium oxide and aluminum oxide powders have good flowability, low agglomeration, good adhesion to the surface of the oxidized steel strip, high activity, and good coating performance, which is beneficial to improving the roughness of the coated steel strip.

[0032] Furthermore, the nickel plating layer is obtained by the following process:

[0033] Trisodium limonene, nickel sulfate, sodium molybdate, ammonium chloride, and sodium hypophosphite were mixed sequentially with deionized water, and ammonia was added to adjust the pH of the system to 8.5 to obtain the plating solution.

[0034] Electroplating is performed on the coated steel strip at a current density of 8–12 A / dm² and a plating solution at 20–40°C to form a nickel plating layer, resulting in the finished stainless steel strip.

[0035] Furthermore, the concentration of trisodium limonene in the plating solution is 90 g / L, the concentration of nickel sulfate is 35 g / L, the concentration of sodium molybdate is 5 g / L, the concentration of ammonium chloride is 30 g / L, and the concentration of sodium hypophosphite is 11 g / L.

[0036] Furthermore, the coating thickness is 0.2–0.5 μm.

[0037] In the above technical solution, the addition of molybdenum and phosphorus elements can promote grain refinement, improve the microstructure, make the coating denser, fill the pores on the steel strip surface, and improve the surface hardness. This effectively reduces the porosity of the finished stainless steel strip surface, resulting in superior corrosion resistance. Thus, finished stainless steel strips with spinel coatings and nickel plating exhibit excellent wear and corrosion resistance while improving tensile strength and hardness.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] The method for preparing ultra-thin precision stainless steel strip of the present invention obtains ultra-thin steel strip through multiple continuous rolling, annealing and heat treatment processes, with a flat plate surface and improved mechanical properties and appearance; and through silicon deposition, oxidation, coating and high temperature sintering processes, a spinel coating is set on the surface of the steel strip, and a nickel plating layer is formed by electroplating, so that the finished stainless steel strip has excellent wear resistance and corrosion resistance while improving tensile strength and hardness, and can be adapted to a variety of applications. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] S1, Rolling:

[0043] (1) One-pass rolling: Take a steel strip with a thickness of 0.42mm and roll it in 9 passes, with the total deformation controlled at 50%;

[0044] The rolling force is 150–400 KN, the rolling tension is 5–60 KN, the rolling speed is 80–150 m / min, and the process parameters increase stepwise with the number of rolling passes.

[0045] (2) First annealing: Annealing at 800℃ in a hydrogen atmosphere at a rate of 8m / min; degreasing and cleaning in water at 60℃ at a rate of 60m / min; drying with nitrogen.

[0046] (3) Secondary rolling: Four rolling passes are performed, and the total deformation is controlled at 60%;

[0047] The rolling force is 100–350 KN, the rolling tension is 5–50 KN, the rolling speed is 60–120 m / min, and the process parameters increase stepwise with the number of rolling passes.

[0048] (4) Secondary annealing: Annealing in a hydrogen atmosphere at 1050℃ at a rate of 10m / min; degreasing and cleaning in water at 60℃ at a rate of 60m / min; drying with nitrogen.

[0049] (5) Straightening treatment: Straighten with an elongation of 0.3% and a tension of 700 N / mm²;

[0050] (6) Heat treatment: Annealing at 500°C in a hydrogen atmosphere, with an annealing rate of 18 m / min and a tension of 85 N / mm²; Cooling in a hydrogen atmosphere, with the dew point of hydrogen controlled at -50°C and the oxygen content controlled at 50 ppm, to obtain heat-treated steel strip.

[0051] In the above hydrogen atmosphere, hydrogen accounts for 95% of the volume, and the remainder is nitrogen.

[0052] S2. Surface treatment:

[0053] (1) Preparation of spinel coating:

[0054] 1.1. Silicon deposition: The heat-treated steel strip is placed in acetone, ultrasonically cleaned for 15 minutes to remove oil, washed with ethanol, and dried with nitrogen.

[0055] Place it in a deposition furnace, evacuate to 10 Pa, heat to 450 °C, introduce a silicon infiltration source, and deposit for 15 min; remove it and sinter at 1000 °C for 60 min to obtain silicon-infiltrated steel;

[0056] The silicon infiltration source includes silicon tetrahydrode and argon, with argon accounting for 90% of the volume.

[0057] 1.2. Oxidation: Chromium powder and chromium oxide are mixed and placed in a sealed device with silicon-impregnated steel. The vacuum is then drawn to 10 Pa. The mixture is then heat-treated at 700℃ for 5.0 h to generate silicon oxide and obtain anodized steel strip.

[0058] The mass ratio of chromium powder to chromium oxide is 0.5:1; the average particle size is 68 μm.

[0059] 1.3. Coating: Mix magnesium oxide, aluminum oxide and deionized water at 7°C to prepare a coating solution with a mass concentration of 12%; keep the environment at 7°C and immerse the anodized steel strip for 9 seconds; take it out and dry it at 280°C for 2 minutes.

[0060] In a nitrogen atmosphere, the temperature is raised to 700℃ and held for 2 hours; then the temperature is raised to 900℃ at a rate of 16℃ / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1170℃ and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

[0061] Both magnesium oxide and aluminum oxide are spherical with an average particle size of 120 nm; the mass ratio of magnesium oxide to aluminum oxide is 1:1.5.

[0062] (2) Preparation of nickel plating:

[0063] Trisodium limonene, nickel sulfate, sodium molybdate, ammonium chloride, and sodium hypophosphite were mixed sequentially with deionized water, and ammonia was added to adjust the pH of the system to 8.5 to obtain the plating solution.

[0064] With 8A / dm 2 The current density is set at 20℃, and the coating steel strip is electroplated in a plating solution to form a nickel plating layer, thus obtaining the finished stainless steel strip.

[0065] The concentrations of trisodium limonene in the plating solution were 90 g / L, nickel sulfate 35 g / L, sodium molybdate 5 g / L, ammonium chloride 30 g / L, and sodium hypophosphite 11 g / L; the coating thickness was 0.2 μm.

[0066] Example 2

[0067] S1, Rolling:

[0068] (1) One rolling: Take a steel strip with a thickness of 0.42mm and roll it 10 times. The total deformation is controlled at 65%; the rolling force is 150~400KN, the rolling tension is 5~60KN, the rolling speed is 80~150m / min, and the process parameters increase stepwise with the rolling pass.

[0069] (2) First annealing: Annealing at 840°C in a hydrogen atmosphere at a rate of 10 m / min; degreasing and cleaning in water at 70°C at a rate of 80 m / min; drying with nitrogen.

[0070] (3) Secondary rolling: Five rolling passes are performed, with the total deformation controlled at 65%; the rolling force is 100-350KN, the rolling tension is 5-50KN, the rolling speed is 60-120m / min, and the process parameters increase stepwise with the number of rolling passes.

[0071] (4) Secondary annealing: Annealing in a hydrogen atmosphere at 1080℃ at a rate of 12m / min; degreasing and cleaning in water at 70℃ at a rate of 80m / min; drying with nitrogen.

[0072] (5) Straightening treatment: Straighten with an elongation of 0.5% and a tension of 750 N / mm²;

[0073] (6) Heat treatment: Annealing at 520°C in a hydrogen atmosphere, with an annealing rate of 20 m / min and a tension of 120 N / mm²; Cooling in a hydrogen atmosphere, with the hydrogen dew point controlled at -60°C and the oxygen content controlled at 30 ppm, to obtain heat-treated steel strip.

[0074] In the above hydrogen atmosphere, hydrogen accounts for 97% of the volume, and the remainder is nitrogen.

[0075] S2. Surface treatment:

[0076] (1) Preparation of spinel coating:

[0077] 1.1. Silicon deposition: The heat-treated steel strip was placed in acetone, ultrasonically cleaned for 18 minutes to remove oil, washed with ethanol, and dried with nitrogen.

[0078] Place it in a deposition furnace, evacuate to 15 Pa, heat to 500 °C, introduce a silicon infiltration source, and deposit for 20 min; remove it and place it at 1050 °C for high-temperature sintering for 60 min to obtain silicon-infiltrated steel.

[0079] The silicon infiltration source includes silicon tetrahydrode and argon, with argon accounting for 90% of the volume.

[0080] 1.2. Oxidation: Chromium powder and chromium oxide are mixed and placed in a sealed device with silicon-impregnated steel. The vacuum is then drawn to 15 Pa. The mixture is then heat-treated at 750℃ for 5.4 h to generate silicon oxide and obtain anodized steel strip.

[0081] The mass ratio of chromium powder to chromium oxide is 0.8:1; the average particle size is 74 μm.

[0082] 1.3. Coating: Mix magnesium oxide, aluminum oxide and deionized water at 5°C to prepare a coating solution with a mass concentration of 12.5%; keep the environment at 5°C and immerse the steel oxide strip for 9.5 seconds; take it out and dry it at 300°C for 3 minutes.

[0083] In a nitrogen atmosphere, the temperature is raised to 710℃ and held for 2 hours; then the temperature is raised to 910℃ at a rate of 17℃ / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1180℃ and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

[0084] Both magnesium oxide and aluminum oxide are spherical with an average particle size of 85 nm; the mass ratio of magnesium oxide to aluminum oxide is 1:2.2.

[0085] (2) Preparation of nickel plating:

[0086] Trisodium limonene, nickel sulfate, sodium molybdate, ammonium chloride, and sodium hypophosphite were mixed sequentially with deionized water, and ammonia was added to adjust the pH of the system to 8.5 to obtain the plating solution.

[0087] Electroplating of the coated steel strip with a current density of 10A / dm2 and a plating solution at 30℃ forms a nickel plating layer, resulting in the finished stainless steel strip.

[0088] The concentrations of trisodium limonene in the plating solution were 90 g / L, nickel sulfate 35 g / L, sodium molybdate 5 g / L, ammonium chloride 30 g / L, and sodium hypophosphite 11 g / L; the coating thickness was 0.3 μm.

[0089] Example 3

[0090] S1, Rolling:

[0091] (1) One rolling: Take a steel strip with a thickness of 0.42mm and roll it in 12 passes. The total deformation is controlled at 80%; the rolling force is 150-400KN, the rolling tension is 5-60KN, the rolling speed is 80-150m / min, and the process parameters increase stepwise with the rolling passes.

[0092] (2) First annealing: Annealing at 880℃ in a hydrogen atmosphere at a rate of 15m / min; degreasing and cleaning in water at 80℃ at a rate of 100m / min; drying with nitrogen.

[0093] (3) Secondary rolling: Six rolling passes are performed, with the total deformation controlled at 70%; the rolling force is 100-350KN, the rolling tension is 5-50KN, the rolling speed is 60-120m / min, and the process parameters increase stepwise with the number of rolling passes.

[0094] (4) Secondary annealing: Annealing in a hydrogen atmosphere at 1120℃ at a rate of 15m / min; degreasing and cleaning in water at 80℃ at a rate of 100m / min; drying with nitrogen.

[0095] (5) Straightening treatment: Straighten with an elongation of 0.7% and a tension of 800 N / mm²;

[0096] (6) Heat treatment: Annealing at 550°C in a hydrogen atmosphere, with an annealing rate of 25 m / min and a tension of 150 N / mm²; Cooling in a hydrogen atmosphere, with the hydrogen dew point controlled at -70°C and the oxygen content controlled at 10 ppm, to obtain heat-treated steel strip.

[0097] In the above hydrogen atmosphere, hydrogen accounts for 99% of the volume, and the remainder is nitrogen.

[0098] S2. Surface treatment:

[0099] (1) Preparation of spinel coating:

[0100] 1.1. Silicon deposition: The heat-treated steel strip is placed in acetone, ultrasonically cleaned for 20 minutes to remove oil, washed with ethanol, and dried with nitrogen.

[0101] Place it in a deposition furnace, evacuate to 20 Pa, heat to 550 °C, introduce a silicon infiltration source, and deposit for 25 min; remove it and place it at 1100 °C for high-temperature sintering for 60 min to obtain silicon-infiltrated steel.

[0102] The silicon infiltration source includes silicon tetrahydrode and argon, with argon accounting for 90% of the volume.

[0103] 1.2. Oxidation: Chromium powder and chromium oxide are mixed and placed in a sealed device with silicon-impregnated steel. The vacuum is then drawn to 20 Pa. The mixture is then heat-treated at 800℃ for 5.8 h to generate silicon oxide and obtain anodized steel strip.

[0104] The mass ratio of chromium powder to chromium oxide is 1.2:1; the average particle size is 80 μm.

[0105] 1.3. Coating: Mix magnesium oxide, aluminum oxide and deionized water at 3°C ​​to prepare a coating solution with a mass concentration of 13%; keep the environment at 7°C and immerse the anodized steel strip for 10 seconds; take it out and dry it at 320°C for 5 minutes.

[0106] In a nitrogen atmosphere, the temperature is raised to 720℃ and held for 2 hours; then the temperature is raised to 920℃ at a rate of 18℃ / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1200℃ and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

[0107] Both magnesium oxide and aluminum oxide are spherical with an average particle size of 50 nm; the mass ratio of magnesium oxide to aluminum oxide is 1:3.0.

[0108] (2) Preparation of nickel plating:

[0109] Trisodium limonene, nickel sulfate, sodium molybdate, ammonium chloride, and sodium hypophosphite were mixed sequentially with deionized water, and ammonia was added to adjust the pH of the system to 8.5 to obtain the plating solution.

[0110] Electroplating of the coated steel strip with a current density of 12A / dm2 and a plating solution at 40℃ forms a nickel plating layer, resulting in the finished stainless steel strip.

[0111] The concentrations of trisodium limonene in the plating solution were 90 g / L, nickel sulfate 35 g / L, sodium molybdate 5 g / L, ammonium chloride 30 g / L, and sodium hypophosphite 11 g / L; the coating thickness was 0.5 μm.

[0112] Comparative Example 1

[0113] The heat treatment step (6) in process S1 was removed; other processes and parameters are the same as in Example 1.

[0114] Comparative Example 2

[0115] (4) and (6) in process S1 were deleted; other processes and parameters are the same as in Example 1.

[0116] Comparative Example 3

[0117] (1) 1.1 in process S2 was deleted, and silicon and oxidation were not deposited on the surface of the heat-treated steel strip; other processes and parameters were the same as in Example 1.

[0118] Comparative Example 4

[0119] Replace (1) in process S2 with the following process:

[0120] Magnesium oxide, aluminum oxide, silicon dioxide, and deionized water were mixed at 7°C to prepare a coating solution with a mass concentration of 12%; the steel strip was immersed in the solution for 9 seconds while maintaining the 7°C environment; it was then removed and dried at 280°C for 2 minutes.

[0121] In a nitrogen atmosphere, the temperature is raised to 700℃ and held for 2 hours; then the temperature is raised to 900℃ at a rate of 16℃ / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1170℃ and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

[0122] Magnesium oxide, aluminum oxide, and silicon dioxide are all spherical with an average particle size of 120 nm; the mass ratio of magnesium oxide, aluminum oxide, and silicon dioxide is 1:1.5:0.4.

[0123] Other processes and parameters are the same as in Example 1.

[0124] Comparative Example 5

[0125] (1) 1.2 in process S2 was deleted, and silicon and oxidation were deposited only on the surface of the heat-treated steel strip; other processes and parameters were the same as in Example 1.

[0126] Comparative Example 6

[0127] (1) in process S2 was deleted, no spinel coating was applied to the surface of the heat-treated steel strip, and the plating solution did not contain sodium molybdate or sodium hypophosphite; other processes and parameters were the same as in Example 1.

[0128] experiment

[0129] The finished stainless steel strips obtained in Examples 1-3 and Comparative Examples 1-6 were used to prepare samples, and their properties were tested and the test results were recorded:

[0130] Roughness: Five tests were performed on the sample surface using a roughness tester, and the average value was taken.

[0131] Hardness: Using QB / T 3822 as the reference standard, the Vickers hardness tester was used to test the overall hardness of the sample. The test load was 200g, and 5 evenly distributed points on the sample were tested, and the average value was taken.

[0132] Corrosion resistance: The test was conducted using the ASTM B117-2011 neutral salt spray test as a reference standard. The samples were placed in a salt spray test chamber for testing. The salt spray solution used in the test was a 5 wt.% sodium chloride solution with a pH of 7.0. The test temperature was 35℃ and the test time was 720h. After the test, the surface morphology and corrosion phenomenon of the samples were observed, and the corrosion rating was calculated (corrosion rating = 3(2-LogA), where A is the percentage of the total area of ​​austenitic steel strip corrosion after the test).

[0133] Friction resistance test: The wear resistance of the specimens was tested using a high-speed reciprocating friction tester. The friction pair was a silicon nitride ball with a diameter of 3 mm. The load was 10 N, the reciprocating distance was 5 mm, and the action time was 10 min. The wear area was measured using a non-contact optical profilometer, and the wear rate was calculated as the wear volume of the wear track / wear distance / external load pressure.

[0134] Table 1:

[0135] Heat-treated steel strip Thickness (mm) Surface roughness Ra (μm) Unevenness (mm / m) Vickers hardness (HV) Example 1 0.08 0.22 0.11 187.6 Example 2 0.05 0.18 0.06 198.4 Example 3 0.03 0.21 0.09 192.5 Comparative Example 1 0.08 0.27 0.17 176.8 Comparative Example 2 0.09 0.33 0.22 163.5

[0136] Table 2:

[0137] Finished product Vickers hardness (HV) Roughness (μm) Corrosion resistance rating <![CDATA[Wear rate (×10 -4 mm / Nm)]]> Tensile strength (GPa) Example 1 236.1 0.71 Level 10 0.20 2.20 Example 2 245.3 0.63 Level 10 0.17 2.27 Example 3 242.0 0.68 Level 10 0.19 2.24 Comparative Example 3 233.4 0.72 Level 9 0.41 2.02 Comparative Example 4 227.2 0.84 Level 8 0.54 1.85 Comparative Example 5 221.6 0.79 Level 5 0.33 1.67 Comparative Example 6 176.3 0.75 Level 6 0.70 1.50

[0138] Based on the data in the table above, the following conclusions can be clearly drawn:

[0139] The finished stainless steel strips obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-6. The test results show that...

[0140] Compared with Comparative Examples 1-6, the heat-treated steel strips and finished stainless steel strips obtained in Examples 1-3 have superior experimental data, which fully demonstrates that the present invention has achieved improvements in the tensile strength, hardness, wear resistance and corrosion resistance of finished stainless steel strips.

[0141] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0142] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an ultra-thin precision stainless steel strip, characterized in that: Including the following processes: (1) One-time rolling: The steel strip is continuously rolled in 9 to 12 passes; (2) Single annealing: Annealing at 800-880℃, annealing speed 8-15m / min; (3) Secondary rolling: Continuous rolling is carried out, with 4 to 6 passes; (4) Secondary annealing: Annealing at 1050~1120℃, annealing speed 10~15m / min; (5) Straightening treatment: Straighten with an elongation of 0.3-0.7% and a tension of 700-800 N / mm²; (6) Heat treatment: Annealing at 500-550℃ to obtain heat-treated steel strip; The surface of the heat-treated steel strip is sequentially coated with a spinel coating and a nickel plating layer. The spinel coating is obtained by the following process: (1) Silicon deposition: Place it in a deposition furnace, evacuate, heat to 450-550℃, introduce silicon tetrahydrogen, and deposit for 15-25 minutes; take it out and place it at 1000-1100℃ for high-temperature sintering for 60 minutes to obtain silicon-dipped steel. (2) Oxidation: Take chromium powder and chromium oxide, place them in a sealed device with silicon-impregnated steel, and evacuate to 10-20 Pa; place them at 700-800℃ for heat treatment for 5.0-5.8 h to generate silicon oxide and obtain anodized steel strip; (3) Coating: Mix magnesium oxide, aluminum oxide and deionized water at 3-7°C to prepare a coating solution with a mass concentration of 12-13%; immerse the steel oxide strip for 9-10 seconds; remove and dry; The temperature is raised to 700-720℃ and held for 2 hours; then the temperature is raised to 900-920℃ at a rate of 16-18℃ / h, and a mixture of nitrogen and hydrogen is introduced; the temperature is further raised to 1170-1200℃ and held at a constant temperature in a hydrogen atmosphere for 5 hours; the furnace is then cooled to form a spinel coating, resulting in a coated steel strip.

2. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: The (1) one-time rolling process is as follows: the total deformation is controlled at 50-80%; the rolling force is 150-400KN, the rolling tension is 5-60KN, and the rolling speed is 80-150m / min.

3. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: The (3) secondary rolling process is as follows: the total deformation is controlled at 60-70%; the rolling force is 100-350KN, the rolling tension is 5-50KN, and the rolling speed is 60-120m / min.

4. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: The heat treatment process described in (6) is as follows: annealing speed 18-25 m / min, tension 85-150 N / mm. 2 .

5. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: After heat treatment (6), the mixture is cooled in a hydrogen atmosphere, with the dew point of the hydrogen controlled at -70 to -50°C and the oxygen content controlled at 10 to 50 ppm.

6. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: After the first annealing (2) and the second annealing (4), the mixture is cooled to room temperature in a hydrogen atmosphere and then degreased and cleaned in water at 60-80°C at a speed of 60-100 m / min; it is then dried with nitrogen.

7. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: The steel strip is made of 316 stainless steel and has a thickness of 0.34 to 0.48 mm.

8. The method for preparing an ultra-thin precision stainless steel strip according to claim 1, characterized in that: The nickel plating layer is obtained by the following process: Trisodium limonene, nickel sulfate, sodium molybdate, ammonium chloride, and sodium hypophosphite were mixed sequentially with deionized water, and ammonia was added to adjust the pH of the system to 8.5 to obtain the plating solution. At 8-12 A / dm 2 The current density is adjusted, and the plating solution at 20-40℃ is used to electroplate the coated steel strip to form a nickel plating layer, thus obtaining the finished stainless steel strip.