A strip steel and a method for preparing the same

Abstract

The present invention proposes a strip steel and a preparation method thereof, belonging to the technical field of strip steel. The method comprises the following steps: S1. After hot rolling, the substrate is coiled and dephosphorized with high-pressure water; S2. The product is subjected to acid treatment to remove the oxide scale; S3. The product is cold rolled; S4. The product is subjected to low-temperature annealing; S5. The product in step S4 is cleaned and nickel-plated; S6. The product is subjected to alloying annealing; S7. Smoothing and rolling are performed to obtain the strip steel. The production process of the pre-nickel-plated strip steel produced by the present invention is simple, has good mechanical properties, high hardness, good stability and good machinability, can make the product thickness tolerance fluctuation small, the coating uniformity is good, the surface roughness is small, the surface quality is stable, and the batch preparation is controllable. The thickness is thin and can cover the use requirements of battery shells, energy storage materials, home appliances, automobiles and other industries.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel, and in particular to a strip steel and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy industry, the demand and requirements for new energy vehicle batteries are also getting higher and higher. Battery shells made of nickel-plated cold-rolled sheets have gradually come into the public eye due to their superior properties such as high hardness and high temperature resistance. However, due to the strict requirements of the automotive industry and the production process limitations of nickel-iron alloys, there is currently no product in China that has the ability to be installed. The current market demand for large 4680 cylindrical battery shells for vehicles is blank in China, and cylindrical batteries such as 2170 and 18650 are only used in power batteries such as hand tools.

[0003] However, customers have higher requirements for this type of product, including: thickness tolerance: ±0.01mm; width tolerance: ±0.05mm; coating uniformity: 5%; roughness Ra: 0.5-1.1μm; tensile strength ≥370MPa; elongation ≥25%; surface hardness (HR30T): 57-65; surface quality is not lower than the FC grade standard of cold-rolled strip in the steel industry

[0004] Therefore, the current product performance cannot meet all the performance requirements of customers, or cannot form batch and large-scale production. Summary of the invention

[0005] The purpose of the present invention is to propose a strip steel and a preparation method thereof, which has a simple process method, good mechanical properties, high hardness, stability and good machinability, can make the product thickness tolerance fluctuation small, the coating uniformity good, the surface roughness small, the surface quality stable, the controllable batch preparation, the thickness is thin, and can cover the use requirements of battery shells, energy storage materials, home appliances, automobiles and other industries.

[0006] The technical solution of the present invention is achieved in this way:

[0007] The present invention provides a method for preparing a strip steel, comprising the following steps:

[0008] S1. Hot rolling: After hot rolling, the substrate is coiled and dephosphorized with high-pressure water;

[0009] S2. Removal of oxide skin: The product in step S1 is treated with acid to remove the oxide skin;

[0010] S3. Cold rolling: cold rolling the product in step S2;

[0011] S4 low temperature annealing; the product in step S3 is subjected to low temperature annealing;

[0012] S5. Continuous nickel electroplating; the product in step S4 is cleaned and nickel-plated;

[0013] S6 alloying annealing: alloying annealing the product in step S3;

[0014] S7. Post-processing: leveling, rolling, and obtaining strip steel.

[0015] As a further improvement of the present invention, the components of the substrate are: C: 0.05-0.9%; Mn: 0.1-1.5%; P: ≤0.5%; S: ≤0.015%; Ti: ≤0.01%; Ni: ≤0.04%; Cr: 0.02-0.04%; B: ≤0.003%; and the balance is Fe.

[0016] As a further improvement of the present invention, the process parameters of the hot rolling in step S1 are: the heating section temperature is 1100-1150°C, the soaking section temperature is 1150-1200°C, the furnace temperature is 1200-1210°C, the heating time is 80-120min, the final rolling temperature is 810-830°C, the coiling temperature is 550-560°C, and the pressure of the high-pressure water dephosphorization is 12-14Mpa; the acid treatment in step S2 adopts 0.2-0.4mol / L hydrochloric acid or sulfuric acid for 60-120s; the reduction rate in step S3 is ≥50%; the soaking temperature of the low-temperature annealing in step S4 is 600-750°C, and the soaking time is 20-200s.

[0017] As a further improvement of the present invention, the soaking temperature of the alloying annealing in step S6 is 550-800°C, the soaking time is 20-200s, the slow cooling temperature is 600-680°C, the rapid cooling temperature is 200-450°C, the aging temperature is 200-400°C, and the final cooling temperature is 40-160°C; the flattening elongation of the flattening in step S7 is: 0.3-2.0, and the rolling elongation of the rolling is: 2.0-12.

[0018] As a further improvement of the present invention, the nickel plating treatment in step S5 includes at least one of dark nickel plating, semi-bright nickel plating, and full-bright nickel plating, and the cleaning adopts a cleaning solution to remove oil at 40-50°C for 5-10 minutes, and the cleaning solution is an aqueous solution prepared by mixing 15-25g / L sodium phosphate, 4-6g / L sodium hydroxide, and 8-12g / L sodium carbonate.

[0019] As a further improvement of the present invention, the formula of the plating solution for nickel plating is as follows: brightener 0-1.5 g / L, nickel sulfate 250-270 g / L, nickel chloride 35-45 g / L, boric acid 35-40 g / L, wetting agent 0.08-0.12 g / L; the wetting agent is sodium dodecyl sulfate or an emulsifier, and the structural formula of the emulsifier is shown in Formula I:

[0020]

[0021] As a further improvement of the present invention, the synthesis method of the emulsifier is as follows:

[0022] T1. D-glucose, acetic anhydride and sodium acetate are reacted to obtain intermediate 1, the structure of which is as follows:

[0023] T2. Intermediate 1 is reacted with 1,9-nonanediol to obtain intermediate 2, the structure of which is as follows:

[0024] T3. Intermediate 2 is reacted with dimethylaminoethyl chloride to obtain intermediate 3, the structure of which is as follows:

[0025] T4. Intermediate 3 is reacted with 1,3-propane sultone to obtain intermediate 4, the structure of which is as follows:

[0026] T5. Add intermediate 4 to sodium methoxide / methanol solution, adjust the pH value of the solution to 9-10, stir and react to obtain the product.

[0027] As a further improvement of the present invention, in the dark nickel plating, the content of the brightener is 0 g / L, in the semi-bright nickel plating, the content of the brightener is 0.5-0.8 g / L, and in the full-bright nickel plating, the content of the brightener is 0.81-1.5 g / L.

[0028] As a further improvement of the present invention, the brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium salt, sodium salt, and zinc salt, with a mass ratio of 3-5:2-3:0.5-1:0.2-0.3:0.01-0.02:0.15-0.2, the cadmium salt is cadmium chloride or cadmium sulfate, the sodium salt is sodium chloride or sodium sulfate, and the zinc salt is zinc chloride or zinc sulfate.

[0029] The present invention further protects a steel strip produced by the above production method, which has a thickness of 0.05-0.1 mm.

[0030] The present invention has the following beneficial effects:

[0031] The present invention hot-rolls the steel billet after acid treatment to remove the oxide skin, heats it to the temperature range of the austenite single-phase region, can homogenize the structure and dissolve carbides, avoids the coarsening of austenite grains, and then undergoes cold rolling treatment to break the grains of the strip steel structure, which is beneficial to improving the cold rolling deformation energy storage and increasing the recrystallization driving force during the annealing process, thereby improving the comprehensive performance of the strip steel after the annealing process.

[0032] In the present invention, the metal ions cadmium or zinc in the inorganic brightener are firstly adsorbed on the active points on the surface of the coating, and then co-precipitated with nickel ions to inhibit the growth of the coating into the solution, thereby making the coating particles finer, and the zinc ions also have a good brightening effect, so that the obtained coating particles are fine. Although the sodium salt has no great effect on the plating speed and the glossiness of the coating, it can stabilize the solution and be used as a brightening stabilizer.

[0033] Saccharin sodium, 1,4-butynediol and pyridine propane sulfonic acid inner salt reduce the surface tension of the sample through synergistic effect, making hydrogen easy to precipitate, and the reaction proceeds in the direction of nickel ion precipitation, thereby improving the glossiness of the coating and increasing the plating speed. Saccharin sodium is a primary brightener, which refines the grains of the coating through the characteristic functional groups of aromatic sulfonyl groups and improves the ductility of the coating, thereby producing a brightening effect. 1,4-Butynediol and pyridine propane sulfonic acid inner salt are secondary brighteners, which are strongly adsorbed on the cathode surface and play a brightening role through C=O and C≡C, causing the cathode potential to shift significantly negative, thereby making the coating crystallized and fine.

[0034] The brightener composition of the present invention is used in electroplating, so that the prepared coating has good gloss, good leveling, high ductility, low stress, strong corrosion resistance, fast deposition speed and high efficiency, and is extremely low in sensitivity to impurities, and can achieve the characteristics of high electroplating efficiency, ultra-fast brightness and high leveling coating.

[0035] When the wetting agent is sodium dodecyl sulfate or the emulsifier prepared by the present invention, the light emission rate of the coating is accelerated, the leveling ability of the plating solution is improved, the surface tension of the coating is reduced, the coating has extremely high anti-pinhole ability, the consumption of 1,4-butynediol and pyridine propane sulfonic acid inner salt is reduced, and the wetting effect is achieved. The effect of the emulsifier prepared by the present invention is better than that of sodium dodecyl sulfate, and the plating speed can be further increased to a certain extent, and the precipitation of hydrogen can be promoted, which plays a role in refining the grains and makes the coating bright. The wetting agent is used together with the brightener to significantly improve the glossiness of the coating, has a significant brightening effect, and the plating speed is relatively high.

[0036] The pre-nickel-plated steel strip produced by the present invention has a simple production process method, good mechanical properties, high hardness, stability and good machinability, can make the product thickness tolerance fluctuation small, the coating uniformity good, the surface roughness small, the surface quality stable, and the controllable batch preparation. The thickness is thin and can cover the use requirements of battery shells, energy storage materials, home appliances, automobiles and other industries. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0038] In this embodiment, the substrate is a special steel for batteries, and the composition is: C: 0.02-0.9%; Mn: 0.1-1.5%; P: ≤0.5%; S: ≤0.15%; Ti: ≤0.8%; Ni: ≤0.04%; Cr: 0.02-0.04%; B: ≤0.03%; the balance is Fe.

[0039] Preparation Example 1 Synthesis of emulsifier

[0040] Synthesis route:

[0041]

[0042] Here’s how:

[0043] T1. Mix 0.1 mol D-glucose, 1 mol acetic anhydride and 0.75 mol sodium acetate, heat to 110°C, stir and react for 1 hour, filter, wash and dry the product to obtain intermediate 1; ESI-MS calculated value: C 16 H 23 O 11 (M+H) + 391.12, found: 391.1, yield: 81.9%.

[0044] NMR results: 1 H NMR (300 MHz, CDCl 3 ) δ6.67 (d, 1H), 5.24 (m, 2H), 4.75 (d, 1H), 4.62 (d, 1H), 4.21 (d, 2H), 2.02 (s, 15H).

[0045] T2. Add 0.1 mol of intermediate 1 and 0.09 mol of 1,9-nonanediol to 100 mL of dichloromethane, and add 0.02 mol of BF 3 ·Et 2 O, stirred for 15 h, washed with equal volumes of saturated sodium bicarbonate and saturated brine, extracted with dichloromethane, dried, concentrated the filtrate, and purified by column chromatography (V 石油醚 :V 乙酸乙酯 =5:1) to separate and purify the intermediate 2; ESI-MS calculated value: C 23 H 39 O 11 (M+H)+ 491.24, found: 491.2, yield: 84.7%.

[0046] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ5.80(d,1H),5.25(m,2H),4.73(d,1H),4.64(d,1H),4.22(d,2H),3.52(t,2H) , 3.37(t, 2H), 2.0(br, 1H), 2.07(s, 12H), 1.45-1.47(m, 4H), 1.28-1.30(m, 10H).

[0047] T3. Add 0.1 mol of intermediate 2, 0.5 mol of triethylamine and 0.09 mol of dimethylaminoethyl chloride to 200 mL of dichloromethane, heat to reflux, stir and react for 4 h, wash with equal volumes of saturated sodium bicarbonate and saturated brine, extract with dichloromethane, dry, concentrate the filtrate, and use column chromatography (V 石油醚 :V 乙酸乙酯 =8:1) to separate and purify the intermediate 3; ESI-MS calculated value: C 27 H 48 NO 11 (M+H) + 562.31, found: 562.3, yield: 91.2%.

[0048] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ5.72(d, 1H), 5.25(m, 2H), 4.73(d, 1H), 4.64(d, 1H), 4.22(d, 2H), 3.47(t, 2H), 3.35( m, 4H), 2.54 (t, 2H), 2.27 (s, 6H), 2.07 (s, 12H), 1.45-1.47 (m, 4H), 1.28-1.30 (m, 10H).

[0049] T4. Dissolve 0.1 mol of intermediate 3 and 0.12 mol of 1,3-propane sultone in 200 mL of acetone, heat to 55°C, stir and react for 20 h, filter, wash and dry to obtain intermediate 4; ESI-MS calculated value: C 29 H 54 NO 14 S(M+H) + 684.32, found: 684.3, yield: 80.3%.

[0050] NMR results: 1H NMR (300 MHz, CDCl 3 )δ5.74(d,1H),5.24(m,2H),4.71(d,1H),4.65(d,1H),4.22(d,2H),3.49(t,2H),3.35(m,4H),3.22( t, 2H), 2.54 (t, 2H), 2.27 (s, 6H), 2.07 (s, 12H), 1.82 (m, 2H), 1.45-1.47 (m, 4H), 1.28-1.30 (m, 12H).

[0051] T5. Add 0.1 mol of intermediate 4 to 100 mL of methanol solution containing 5 wt% sodium methoxide, adjust the solution pH to 10, stir and react for 30 min, adjust the solution pH to neutral with acetic acid, filter, wash, and dry to obtain the product. ESI-MS calculated value: C 22 H 46 NO 10 S(M+H) + 516.28, found: 516.3, yield: 94.3%.

[0052] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ5.75(d,1H),5.21(m,2H),4.75(d,1H),4.65(d,1H),4.22(d,2H),3.47(t,2H),3.37(m,4H),3.22 (t, 2H), 2.54 (t, 2H), 2.27 (s, 6H), 2.0 (br, 4H), 1.84 (m, 2H), 1.46-1.48 (m, 4H), 1.29-1.31 (m, 12H).

[0053] Example 1

[0054] This embodiment provides a method for preparing a strip steel, comprising the following steps:

[0055] S1. Hot rolling: After the substrate is hot rolled, it is coiled and dephosphorized by high-pressure water at a pressure of 12Mpa;

[0056] The process parameters of hot rolling are: heating section temperature is 1100℃, soaking section temperature is 1150℃, furnace temperature is 1200℃, heating time is 80min, final rolling temperature is 810℃, and coiling temperature is 550℃.

[0057] S2. Removal of oxide skin: The product in step S1 was treated with 0.2 mol / L hydrochloric acid for 60 s to remove the oxide skin;

[0058] S3. Cold rolling: cold rolling the product in step S2, with a reduction rate of ≥50%;

[0059] S4 low temperature annealing; the product in step S3 is subjected to low temperature annealing, wherein the soaking temperature of the low temperature annealing is 750°C and the soaking time is 20s;

[0060] S5. Continuous nickel electroplating; the product in step S4 is cleaned and nickel-plated;

[0061] Degreasing at 40°C for 5 minutes using a cleaning solution, wherein the cleaning solution is an aqueous solution prepared by mixing 15 g / L sodium phosphate, 4 g / L sodium hydroxide, and 8 g / L sodium carbonate;

[0062] The nickel plating treatment is full bright nickel plating, and the formula of the plating solution for the nickel plating treatment is as follows: brightener 0.81g / L, nickel sulfate 250g / L, nickel chloride 35g / L, boric acid 35g / L, wetting agent 0.08g / L; the wetting agent is sodium dodecyl sulfate;

[0063] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium chloride, sodium chloride and zinc chloride, and the mass ratio is 3:2:0.5:0.2:0.01:0.15.

[0064] S6 alloying annealing: alloying annealing the product in step S3;

[0065] The alloying annealing has a soaking temperature of 550°C, a soaking time of 200s, a slow cooling temperature of 600°C, a fast cooling temperature of 200°C, an aging temperature of 200°C, and a final cooling temperature of 40°C.

[0066] S7. Post-processing: flattening, flattening elongation: 1.5, rolling, rolling elongation: 10.0, to obtain strip steel.

[0067] Example 2

[0068] This embodiment provides a method for preparing a strip steel, comprising the following steps:

[0069] S1. Hot rolling: After the substrate is hot rolled, it is coiled and dephosphorized by high-pressure water at a pressure of 14Mpa;

[0070] The process parameters of hot rolling are: heating section temperature is 1150℃, soaking section temperature is 1200℃, furnace temperature is 1210℃, heating time is 120min, final rolling temperature is 830℃, coiling temperature is 560℃;

[0071] S2. Removal of oxide skin: The product in step S1 was treated with 0.4 mol / L sulfuric acid for 120 s to remove the oxide skin;

[0072] S3. Cold rolling: cold rolling the product in step S2, with a reduction rate of ≥50%;

[0073] S4 low temperature annealing; the product in step S3 is subjected to low temperature annealing, wherein the soaking temperature of the low temperature annealing is 600°C and the soaking time is 200s;

[0074] S5. Continuous nickel electroplating; the product in step S4 is cleaned and nickel-plated;

[0075] Degreasing at 50°C for 10 minutes using a cleaning solution, wherein the cleaning solution is an aqueous solution prepared by mixing 25 g / L sodium phosphate, 6 g / L sodium hydroxide, and 12 g / L sodium carbonate;

[0076] The nickel plating treatment is full bright nickel plating, and the formula of the plating solution for the nickel plating treatment is as follows: brightener 1.5g / L, nickel sulfate 270g / L, nickel chloride 45g / L, boric acid 40g / L, wetting agent 0.12g / L; the wetting agent is the emulsifier prepared in Preparation Example 1;

[0077] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium sulfate, sodium sulfate, and zinc sulfate, with a mass ratio of 5:3:1:0.3:0.02:0.2.

[0078] S6 alloying annealing: alloying annealing the product in step S3;

[0079] The alloying annealing has a soaking temperature of 550°C, a soaking time of 200s, a slow cooling temperature of 680°C, a fast cooling temperature of 450°C, an aging temperature of 400°C, and a final cooling temperature of 160°C.

[0080] S7. Post-processing: flattening, flattening elongation: 1.5, rolling, rolling elongation: 10, to obtain strip steel.

[0081] Example 3

[0082] This embodiment provides a method for preparing a strip steel, comprising the following steps:

[0083] S1. Hot rolling: After the substrate is hot rolled, it is coiled and dephosphorized by high-pressure water at a pressure of 13Mpa;

[0084] The process parameters of hot rolling are: heating section temperature is 1120℃, soaking section temperature is 1170℃, furnace temperature is 1205℃, heating time is 100min, final rolling temperature is 820℃, coiling temperature is 555℃;

[0085] S2. Removal of oxide skin: The product in step S1 was treated with 0.3 mol / L hydrochloric acid for 100 s to remove the oxide skin;

[0086] S3. Cold rolling: cold rolling the product in step S2, with a reduction rate of ≥50%;

[0087] S4 low temperature annealing; the product in step S3 is subjected to low temperature annealing, wherein the soaking temperature of the low temperature annealing is 670°C and the soaking time is 100s;

[0088] S5. Continuous nickel electroplating; the product in step S4 is cleaned and nickel-plated;

[0089] Degreasing at 45°C for 7 minutes using a cleaning solution, wherein the cleaning solution is an aqueous solution prepared by mixing 20 g / L sodium phosphate, 5 g / L sodium hydroxide, and 10 g / L sodium carbonate;

[0090] The nickel plating treatment is full bright nickel plating, and the formula of the plating solution for the nickel plating treatment is as follows: brightener 1.1g / L, nickel sulfate 260g / L, nickel chloride 40g / L, boric acid 37g / L, wetting agent 0.1g / L; the wetting agent is the emulsifier prepared in Preparation Example 1;

[0091] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium sulfate, sodium sulfate, and zinc sulfate, and the mass ratio is 4:2.5:0.7:0.25:0.015:0.17.

[0092] S6 alloying annealing: alloying annealing the product in step S3;

[0093] The alloying annealing has a soaking temperature of 650°C, a soaking time of 100s, a slow cooling temperature of 640°C, a fast cooling temperature of 350°C, an aging temperature of 300°C, and a final cooling temperature of 110°C;

[0094] S7. Post-processing: flattening, flattening elongation: 1.5, rolling, rolling elongation: 10, to obtain strip steel.

[0095] Example 4

[0096] Compared with Example 3, the difference is that the wetting agent is a mixture of sodium lauryl sulfate and the emulsifier obtained in Preparation Example 1, and the mass ratio is 1:1.

[0097] Comparative Example 1

[0098] Compared with Example 3, the difference is that no cadmium sulfate is added to the brightener of the present invention.

[0099] The details are as follows:

[0100] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, sodium sulfate and zinc sulfate, and the mass ratio is 4:2.5:0.7:0.015:0.42.

[0101] Comparative Example 2

[0102] Compared with Example 3, the difference is that zinc sulfate is not added to the brightener of the present invention.

[0103] The details are as follows:

[0104] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium sulfate and sodium sulfate, and the mass ratio is 4:2.5:0.7:0.42:0.015.

[0105] Comparative Example 3

[0106] Compared with Example 3, the difference is that cadmium sulfate and zinc sulfate are not added to the brightener of the present invention.

[0107] The details are as follows:

[0108] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium and sodium sulfate, with a mass ratio of 4:2.5:0.7:0.015.

[0109] Comparative Example 4

[0110] Compared with Example 3, the difference is that no sodium sulfate is added to the brightener of the present invention.

[0111] The details are as follows:

[0112] The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium sulfate and zinc sulfate, and the mass ratio is 4:2.5:0.7:0.25:0.17.

[0113] Comparative Example 5

[0114] Compared with Example 3, the difference is that no wetting agent is added to the plating solution of the present invention.

[0115] The details are as follows:

[0116] The formula of the plating solution for the nickel plating treatment is as follows: 1.1 g / L of brightener, 260 g / L of nickel sulfate, 40 g / L of nickel chloride, and 37 g / L of boric acid.

[0117] Test Example 1

[0118] The steel strips prepared in Examples 1-4 of the present invention and Comparative Examples 1-5 were subjected to mechanical property tests.

[0119] According to GB / T 2975-1998 "Steel and Steel Products Mechanical Properties Test Sampling Location and Sample Preparation", the strip steel was sampled at 1 / 4 of the strip width in the middle of the strip steel; according to GB / T 228.1-2010 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method" to test its mechanical properties, the tensile specimen direction was longitudinal. The results are shown in Table 1.

[0120] Table 1

[0121] Group Tensile strength(MPa) Elongation at break (%) Example 1 558 27 Example 2 567 30 Example 3 570 31 Example 4 577 33 Comparative Example 1 550 24 Comparative Example 2 548 25 Comparative Example 3 541 22 Comparative Example 4 556 26 Comparative Example 5 539 20

[0122] It can be seen from the above table that the strip steels prepared in Examples 1-4 of the present invention have good mechanical properties.

[0123] Test Example 2

[0124] The performance of the steel strips prepared in Examples 1-4 of the present invention and Comparative Examples 1-5 was tested, and the results are shown in Table 2.

[0125] Table 2

[0126]

[0127] It can be seen from the above table that the comprehensive performance of the strip steels prepared in Examples 1-4 of the present invention is better.

[0128] Test Example 3

[0129] The plating speed and brightness of the continuous nickel electroplating in step S5 in Examples 1-4 of the present invention and Comparative Examples 1-5 were tested. The results are shown in Table 3.

[0130] (1) Plating speed: The plating speed is determined by weighing method, and the calculation formula is:

[0131]

[0132] Where: v is the plating speed, μm / h; m 1 is the mass of the specimen after plating, g; m 0 is the mass of the test piece before plating, g; S is the area of ​​the test piece, cm 2 ; ρ is the density of the test piece, which is 7.85 g / cm 3 ; t is the plating time, h.

[0133] (2) Glossiness of coating: The glossiness of the coating was measured at a projection angle of 60° using an MN-60 gloss meter.

[0134] Table 3

[0135] Group <![CDATA[Plating rate ( μm / h)]]> Coating gloss (Gs) Example 1 12.241 259 Example 2 13.142 268 Example 3 13.447 271 Example 4 13.729 277 Comparative Example 1 10.114 251 Comparative Example 2 10.722 248 Comparative Example 3 9872 237 Comparative Example 4 11.792 253 Comparative Example 5 8.266 195

[0136] It can be seen from the above table that the treatment methods in Examples 1-4 of the present invention have fast plating speed and good glossiness.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a strip steel, characterized in that: The following steps are involved: S1. Hot rolling: After hot rolling, the substrate is coiled and dephosphorized with high-pressure water; S2. Removal of oxide skin: The product in step S1 is treated with acid to remove the oxide skin; S3. Cold rolling: cold rolling the product in step S2; S4 low temperature annealing; the product in step S3 is subjected to low temperature annealing; S5. Continuous nickel electroplating; the product in step S4 is cleaned and nickel-plated; the nickel plating treatment includes at least one of dark nickel plating, semi-bright nickel plating, and full-bright nickel plating, and the cleaning is performed by degreasing with a cleaning solution at 40-50 ° C for 5-10 min, and the cleaning solution is an aqueous solution prepared by mixing 15-25 g / L sodium phosphate, 4-6 g / L sodium hydroxide, and 8-12 g / L sodium carbonate; The formula of the plating solution for nickel plating is as follows: brightener 0-1.5 g / L, nickel sulfate 250-270 g / L, nickel chloride 35-45 g / L, boric acid 35-40 g / L, wetting agent 0.08-0.12 g / L; the wetting agent is an emulsifier, and the structural formula of the emulsifier is shown in Formula I: The synthesis method of the emulsifier is as follows: T1. D-glucose, acetic anhydride and sodium acetate are reacted to obtain intermediate 1, the structure of which is as follows: T2. Intermediate 1 is reacted with 1,9-nonanediol to obtain intermediate 2, the structure of which is as follows: T3. Intermediate 2 is reacted with dimethylaminoethyl chloride to obtain intermediate 3, the structure of which is as follows: T4. Intermediate 3 is reacted with 1,3-propane sultone to obtain intermediate 4, the structure of which is as follows: T5. The intermediate 4 was added with sodium methoxide / methanol solution, the pH value of the solution was adjusted to 9-10, and the reaction was stirred to obtain a product; S6 alloying annealing: alloying annealing the product in step S3; S7. Post-processing: leveling, rolling, and obtaining strip steel.

2. The preparation method according to claim 1, characterized in that: The components of the substrate are as follows: C: 0.05-0.9%; Mn: 0.1-1.5%; P: ≤0.5%; S: ≤0.015%; Ti: ≤0.01%; Ni: ≤0.04%; Cr: 0.02-0.04%; B: ≤0.003%; and the balance is Fe.

3. The preparation method according to claim 1, characterized in that: The process parameters of hot rolling in step S1 are as follows: heating section temperature is 1100-1150°C, soaking section temperature is 1150-1200°C, furnace discharge temperature is 1200-1210°C, heating time is 80-120min, final rolling temperature is 810-830°C, coiling temperature is 550-560°C, and the pressure of high-pressure water dephosphorization is 12-14Mpa; the acid treatment in step S2 adopts 0.2-0.4mol / L hydrochloric acid or sulfuric acid for 60-120s; the reduction rate in step S3 is ≥50%; the soaking temperature of low-temperature annealing in step S4 is 600-750°C, and the soaking time is 20-200s.

4. The preparation method according to claim 1, characterized in that: The soaking temperature of the alloying annealing in step S6 is 550-800°C, the soaking time is 20-200s, the slow cooling temperature is 600-680°C, the rapid cooling temperature is 200-450°C, the aging temperature is 200-400°C, and the final cooling temperature is 40-160°C; the flattening elongation of the flattening in step S7 is 0.3-2.0, and the rolling elongation of the rolling is 2.0-12.

5. The preparation method according to claim 1, characterized in that: In the dark nickel plating, the content of the brightener is 0 g / L, in the semi-bright nickel plating, the content of the brightener is 0.5-0.8 g / L, and in the full-bright nickel plating, the content of the brightener is 0.81-1.5 g / L.

6. The preparation method according to claim 1, characterized in that: The brightener is a mixture of pyridine propane sulfonic acid inner salt, 1,4-butynediol, saccharin sodium, cadmium salt, sodium salt and zinc salt, with a mass ratio of 3-5:2-3:0.5-1:0.2-0.3:0.01-0.02:0.15-0.2, the cadmium salt is cadmium chloride or cadmium sulfate, the sodium salt is sodium chloride or sodium sulfate, and the zinc salt is zinc chloride or zinc sulfate.

7. A steel strip obtained by the preparation method according to any one of claims 1 to 6, characterized in that: Its thickness is 0.05-0.1mm.

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