A method for preparing high-strength nickel coiled material

Abstract

The application discloses a preparation method of high-strength nickel coiled material, which comprises the following steps: vacuum induction smelting raw materials and smelting additives to obtain semi-finished nickel ingot; then, electric-shock remelting is performed to obtain finished nickel ingot; one-fire forging and two-fire forging are performed on the finished nickel ingot respectively to obtain nickel slab; hot continuous rolling is performed on the nickel slab to obtain first semi-finished nickel coiled material; finish rolling is performed on the first semi-finished nickel coiled material on a continuous rolling mill to obtain second semi-finished nickel coiled material; annealing and pickling are performed on the second semi-finished nickel coiled material to obtain soft white nickel coiled material; after cold rolling, online bright annealing is performed on the white nickel coiled material to obtain finished nickel coiled material; through the above steps, the nickel coiled material with comprehensive performance meeting the requirements of special chemical materials can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of metal material processing technology, and specifically relates to a method for preparing high-strength nickel coils. Background Technology

[0002] Pure nickel for industrial production possesses excellent corrosion resistance, making it suitable for use in strong alkalis or other alkaline corrosive solutions. It is an irreplaceable high-quality material with excellent plasticity, widely used in equipment manufacturing in the petroleum and chemical industries. A special type of pure nickel plate and strip for chemical applications, due to its use in continuously high-temperature and high-pressure corrosive media, requires that, in addition to general properties, the nickel plate and strip must meet the following requirements: Rm ≥ 400 MPa and Rp0.2 ≥ 130 MPa (standard requirements: Rm ≥ 345 MPa, Rp0.2 ≥ 80 MPa). The tensile strength of pure nickel plates and strips produced in my country is between 350 and 380 MPa, and the yield strength is typically between 80 and 110 MPa. To achieve these strength requirements, Chinese manufacturers generally use mechanical methods to improve the strength of pure nickel materials. This involves repeatedly stretching and straightening the heat-treated pure nickel plates or strips to increase their strength. However, mechanical methods can only increase the material strength by 15 to 20 MPa, barely enough to pass acceptance tests. Meanwhile, due to the inherent uncertainties of mechanical methods, the plasticity of materials often decreases due to hardening, which greatly reduces the yield of pure nickel plates and strips. Furthermore, mechanical methods increase the manufacturing cost of materials and affect production efficiency to some extent. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides a method for preparing high-strength nickel coils. The technical problem to be solved by this invention is achieved through the following technical solution:

[0004] A method for preparing a high-strength nickel coil includes:

[0005] Step 1: Pure nickel raw material, nickel-niobium alloy, nickel-magnesium alloy, and smelting additives are added to a vacuum induction furnace for vacuum induction melting to obtain semi-finished nickel ingots; wherein, the smelting additives include pure titanium and carbon, and the smelting additives are added based on the total weight of the pure nickel raw material in the following weight ratios: pure titanium 0.01-0.05%, carbon 0.02-0.03%; the added weight of the nickel-niobium alloy accounts for 0.03-0.3% of the total weight of the pure nickel raw material; the added weight of the nickel-magnesium alloy accounts for 0.017-0.17% of the total weight of the pure nickel raw material;

[0006] Step 2: The head of the obtained semi-finished nickel ingot is sawn off and baked, then electroslag remelted. After cooling, the riser and bottom are cut off to obtain the finished nickel ingot. The baking temperature is 400-450℃ and the baking time is 6-7 hours.

[0007] Step 3: Heat the obtained finished nickel ingot to 1020-1050℃, hold for 5.5-6.5h, and then perform a first-fire forging to obtain a nickel slab with a diameter of δ(200-250)mm × W(1200-1350)mm; reheat the nickel slab to 1000-1020℃, hold for 1.5-2.5h, and then perform a second-fire forging to obtain a nickel slab with a diameter of δ(100-120)mm × W(1250-1380)mm × L(≥4000)mm; wherein, the final forging temperature is not lower than 800℃, δ is the thickness, W is the width, and L is the length;

[0008] Step 4: Heat the final nickel slab to 1040-1060℃, hold for 90-110 minutes, and then perform 3-5 passes of hot continuous rolling to obtain the first semi-finished nickel coil with a diameter of δ(25-30)×W(1219-1350)mm.

[0009] Step 5: The obtained first semi-finished nickel coil is heated to 940-970℃ and then precision rolled to obtain the second semi-finished nickel coil with δ(3.0-3.5)mm×W(1250-1380)mm.

[0010] Step 6: Anneal and pickle the obtained second semi-finished nickel coil to obtain a soft whitened nickel coil; wherein, the annealing temperature is 780~800℃ and the annealing speed is 5~5.5m / min;

[0011] Step 7: The obtained whitened nickel coil is cold rolled for 6 to 13 passes to obtain a third semi-finished nickel coil with a diameter of δ(0.6 to 1.5) mm × W(1219 to 1350) mm;

[0012] Step 8: The obtained third semi-finished nickel coil is subjected to online bright annealing to obtain the finished nickel coil; wherein the heat treatment temperature is 730~750℃ and the annealing speed is 3~3.5m / min.

[0013] Furthermore, the nickel-niobium alloy has the following chemical composition by weight ratio: Ni 50%, Nb 50%; the nickel-magnesium alloy has the following chemical composition by weight ratio: Ni 70%, Mg 30%.

[0014] Further, step 1 includes:

[0015] Step 1.1: The pure nickel raw material, carbon, and pure titanium are sequentially added into a vacuum induction furnace for melting. After all materials have melted, refining begins. Liquid metal is obtained after refining. The refining power is 550-580KW, the vacuum degree during refining is less than 5Pa, the refining time is 60-80min, and the vacuum degree after refining is less than or equal to 0.5Pa.

[0016] Step 1.2: Adjust the temperature of the liquid metal to 1400-1420℃, then quickly add nickel-niobium alloy and nickel-magnesium alloy, then increase the melting power to 550KW, and after the nickel-niobium alloy and nickel-magnesium alloy melt, cast the metal, and obtain a semi-finished nickel ingot after cooling.

[0017] Furthermore, in step 6, the acid solution is a mixture of 60% HNO3, 1% HF, and deionized water, and the temperature of the acid solution during pickling is 40-45°C.

[0018] The beneficial effects of this invention are:

[0019] 1. A two-step melting process of vacuum induction melting and electroslag remelting is adopted. Ni50Nb, Ni30Mg, TA1 cold-rolled scrap, and spectral carbon produced in-house are used as additives for desulfurization, impurity removal, and grain refinement. By adjusting the vacuum induction melting process parameters and improving the electroslag remelting process, the content of microalloying elements niobium and magnesium is effectively controlled between 0.02% and 0.2%. The qualified electroslag remelted ingots produced result in nickel coils with low anisotropy, excellent plasticity, tensile strength greater than 400MPa, and yield strength between 135 and 180MPa. The comprehensive performance meets the requirements of special chemical materials.

[0020] 2. Compared with mechanical methods to improve the strength of nickel coils, microalloying strengthening not only greatly improves the strength of the material, but also avoids the risks associated with mechanical methods. It also results in a high overall yield, high production efficiency, and long service life.

[0021] 3. The nickel coil preparation process provided by this invention is simple and easy to operate, providing material support for promoting the healthy development of my country's special chemical industry.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 Photograph of the finished nickel ingot (the riser and bottom of the ingot have not been cut off);

[0024] Figure 2 A photo of a nickel slab after it has been trimmed;

[0025] Figure 3 Photo of the soft, whitened nickel coil;

[0026] Figure 4 Photographs of finished nickel coils;

[0027] Figure 5 A longitudinal metallographic photograph of the finished nickel coil;

[0028] Figure 6Transverse metallographic photograph of the finished nickel coil;

[0029] Figures 7-10 This is a performance report for the finished nickel coil. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0031] Example 1

[0032] This invention provides a method for preparing a δ0.6mm×W1219mm high-strength nickel coil, which includes the following steps:

[0033] Step 1: Electrolytic nickel, nickel-niobium alloy, nickel-magnesium alloy, and smelting additives are added to a vacuum induction furnace for vacuum induction melting to obtain semi-finished nickel ingots. The smelting additives include pure titanium and carbon. The pure titanium is selected from TA1 cold-rolled edge materials, and the carbon is spectral carbon. The addition amount of each component is shown in Table 1. The addition amount of electrolytic nickel is 3500 kg, the addition amount of nickel-niobium alloy is 8 kg, the addition amount of nickel-magnesium alloy is 5 kg, the addition amount of pure titanium is 1.05 kg, and the addition amount of carbon is 0.7 kg.

[0034] Table 1. Amounts of Raw Materials and Smelting Additives

[0035]

[0036] The nickel-niobium alloy has the following chemical composition by weight ratio: Ni 50%, Nb 50%; the nickel-magnesium alloy has the following chemical composition by weight ratio: Ni 70%, Mg 30%.

[0037] Using the applicant's existing 200kg vacuum induction furnace, intermediate alloys Ni50Nb and Ni30Mg were prepared. The raw materials for Ni50Nb were high-purity niobium ingots (Nb-1) and electrolytic nickel, while the raw materials for Ni30Mg were high-purity magnesium ingots (Mg99.95A) and electrolytic nickel (Ni9996). Under high vacuum, the alloys underwent thorough degassing, impurity removal, and homogenization treatments before being finally smelted to produce Ni50Nb and Ni30Mg intermediate alloys. The vacuum level during the melting process was no less than 10... -1 Pa, after further crushing and sieving, yields granular intermediate alloy blocks of 30-50 mm, which are then used as additives.

[0038] Specifically, the steps of vacuum induction melting include:

[0039] Step 1.1: The pure nickel raw material, carbon, and pure titanium are sequentially added into a vacuum induction furnace for melting. After all materials have melted, refining begins. Liquid metal is obtained after refining. The refining power is 565KW, the vacuum degree during refining is less than 5Pa, the refining time is 70min, and the vacuum degree after refining is less than or equal to 0.5Pa.

[0040] Step 1.2: Adjust the temperature of the liquid metal to 1410℃, then quickly add nickel-niobium alloy and nickel-magnesium alloy, then increase the melting power to 550KW, and after the nickel-niobium alloy and nickel-magnesium alloy melt, cast the metal, and obtain a semi-finished nickel ingot after cooling.

[0041] Using the above process, this embodiment of the invention involves two furnace smeltings, using a Ф570mm cast iron mold; all materials must be cleaned before being loaded into the furnace for smelting, producing two finished nickel ingots with individual weights of 3461kg and 3456kg respectively.

[0042] The compositions of the two semi-finished nickel ingots are shown in Table 2:

[0043] Table 2 Chemical composition analysis of semi-finished nickel ingots

[0044]

[0045] This step allows impurity elements to be controlled at low levels, ensuring uniform diffusion of alloy additives, and the Nb and Mg content in the semi-finished nickel ingot is between 0.02% and 0.2%.

[0046] Step 2: After sawing off the head of the obtained semi-finished nickel ingot, it is placed in a resistance furnace for baking and then electroslag remelting. After cooling, the riser and bottom are cut off to obtain the finished nickel ingot. The baking temperature is 430℃ and the baking time is 6.5 hours. A photo of the finished nickel ingot is shown below. Figure 1 As shown ( Figure 1 (The riser and base of the ingot were not cut off).

[0047] Specifically, the baked semi-finished nickel ingots are connected end to end and used as remelting electrodes. The remelting electrodes are preheated before use at a temperature of 630°C for 5 hours.

[0048] The electroslag remelting process uses a water-cooled copper-lined crystallizer with dimensions of Φ680 / Φ720×2200mm. The slag is prepared from CaF2, CaO, Al2O3, and MgF2 in a weight ratio of 6:1:2.5:0.5. The slag is thoroughly mixed and baked in a resistance furnace at 430℃ for 8 hours before use. Before electrode hoisting, the welding quality and concentricity between the electrodes are checked to ensure proper alignment during furnace loading. Arc ignition and slag formation were initiated, followed by remelting. The remelting process was automated, with a current of 13300A, a voltage of 66V, and a melting rate of 565Kg / h. Feeding was initiated 100mm from the electrode tip, with a feeding regime of 10000A current, 59V voltage, and 40min. After cooling, the riser and bottom of the resulting electroslag ingot were removed. The cooling water outlet temperature was 41℃, yielding a finished nickel ingot with a single weight ≥6t. The chemical composition of this finished nickel ingot is shown in Table 3.

[0049] Table 3 Chemical composition of finished nickel ingots (where "head" refers to the riser of the electroslag ingot and "tail" refers to its bottom).

[0050]

[0051] The content of strengthening elements Nb+Mg in the finished nickel ingot is between 0.02% and 0.2%. During the two smelting processes, nickel and niobium form Ni3Nb intermediate compound, and nickel and magnesium form MgCNi3 intermediate compound. These two compounds can promote grain boundary strengthening, which can make the finished nickel ingot have a uniform and fine equiaxed structure, a smooth surface, a low level of interstitial element content, and good forgeability, thereby improving the tensile strength, hardness and yield strength of the final nickel coil.

[0052] Step 3: The obtained finished nickel ingot is heated to 1030℃ in a 300KW bogie furnace and held for 6 hours. Then, it is hot-forged on an 8000t free forging press. The finished nickel ingot is upsetting and drawing in one pass using the forging press, and then flattened, widened and lengthened into a nickel slab with a thickness of 230mm and a width of 1260mm. The nickel slab is then returned to the furnace and heated to 1010℃ and held for 2 hours. After being taken out of the furnace, it is forged. The final forging temperature is not lower than 800℃. Finally, a nickel slab with a thickness of 115mm, a width of 1270mm and a length of 4850mm is obtained.

[0053] The forging process in this step ensures that the ingot has good forgeability and hot working properties, thereby obtaining the target slab.

[0054] Step 4: Finish the final nickel slab, including milling, sharpening the edges, and then polishing the surface, with the side edges chamfered at 45°. Figure 2As shown, this process ensures that the final slab has a smooth and flat surface, free from defects such as indentations, cracks, and folds that are visible to the naked eye. The nickel slab is then sent to the continuous rolling mill, where it is heated to 1050°C using a walking beam furnace and held for 100 minutes. After exiting the furnace, the slab is subjected to five passes of hot continuous rolling on an R1 four-roll roughing mill. The thickness of the slab varies from 110mm to 90mm, 71mm, 55mm, 36mm, and 25mm. After rolling, a first semi-finished nickel coil with a thickness of 25mm and a width of 1260mm is obtained.

[0055] The process in step 4 helps to obtain a first semi-finished nickel coil with low deformation resistance and high plasticity, ultimately resulting in a nickel coil with good shape, small differences between sheets, and good surface quality, avoiding problems such as cracking and breakage caused by work hardening.

[0056] Step 5: Place the obtained first semi-finished nickel coil into a hot rolling box and heat it to 960℃. Then, perform precision rolling on the F1-F8 finishing mill to obtain the second semi-finished nickel coil with a thickness of 3.4mm and a width of 1273mm.

[0057] Step 6: The obtained second semi-finished nickel coil is fed into the annealing and pickling line for annealing and pickling. The annealing temperature is 790℃, and the annealing speed (i.e., the travel speed of the second semi-finished nickel coil) is 5.2 m / min. The acid solution is a mixture of 60% HNO3, 1% HF, and deionized water in a volume ratio of 65:5:30. The acid solution temperature during pickling is 42℃. Finally, the coil is rolled and bundled to obtain a soft, whitened nickel coil, which ensures good plasticity for subsequent processing. A photo of this whitened nickel coil is shown below. Figure 3 As shown in Table 4, and after on-site sampling and testing, the performance of the whitened nickel coil is as follows:

[0058] Table 4 Performance of Nickel Whitening Coil

[0059]

[0060] Step 7: After trimming the edges of the obtained whitened nickel coil, place it on a 20-roll reversible cold rolling mill. After trimming the edges of the rough coil, roll it into a third semi-finished nickel coil with a thickness of 0.6 mm and a width of 1230 mm through 13 passes and one rolling stroke. The main parameters in this rolling process are: tension 100~320KN, total rolling force 1200~2300T, and rolling speed 45m / s.

[0061] Step 8: The obtained third semi-finished nickel coil is subjected to online bright annealing, specifically on a 1350mm wide strip continuous annealing line. The protective atmosphere is argon, the heat treatment temperature is 740℃, and the annealing speed, i.e., the travel speed of the third semi-finished nickel coil, is 3m / min. After edge trimming, a finished nickel coil with a thickness of 0.6mm and a width of 1219mm is obtained. This finished nickel coil is then cut into nickel plates and strips according to user requirements. A photo of the finished nickel coil is shown below. Figure 4 As shown.

[0062] Samples were taken from both ends of the finished nickel coil for analysis. The test results are shown in Table 5. Figures 5-10 ;

[0063] Table 5. Test results of finished nickel coils in Example 1

[0064]

[0065] Analysis of the non-metallic inclusions in the finished nickel coil showed that both sulfides and carbides met the Class 1 requirements of B.1. The control of non-standard impurity elements such as H, O, and N was also effective, and the content of these impurity elements is shown in Table 6.

[0066] Table 6. Analysis of Impurity Element Composition of Finished Nickel Coils

[0067] element O N H content / % ≤0.0020 ＜0.0010 0.0004

[0068] Based on practical applications and test results, the nickel coils prepared in this application are of excellent quality and have superior comprehensive performance. While meeting ASME SB162, the Nb+Mg dual-phase strengthening process results in a final nickel coil tensile strength ≥400MPa and Rp0.2 ≥130MPa. The workpieces made from this material perform well in corrosive media under continuous high temperature and high pressure, fully meeting the requirements of special chemical materials. In particular, compared with equivalent materials, the product of this invention significantly improves the workpiece manufacturing yield and service life, solving the "bottleneck" technical problem of nickel plates and strips for my country's chemical industry.

[0069] Example 2

[0070] This invention provides a method for preparing a δ0.7mm×W1230mm high-strength nickel coil, which includes the following steps:

[0071] Step 1: Electrolytic nickel, nickel-niobium alloy, nickel-magnesium alloy, and smelting additives are added to a vacuum induction furnace for vacuum induction melting to obtain semi-finished nickel ingots. The smelting additives include pure titanium and carbon. The pure titanium is selected from TA1 cold-rolled scrap, and the carbon is spectral carbon. The addition amounts of each component are as follows: 3500 kg of electrolytic nickel, 8.75 kg of nickel-niobium alloy, 4.2 kg of nickel-magnesium alloy, 1.4 kg of pure titanium, and 1.05 kg of carbon.

[0072] Specifically, the steps of vacuum induction melting include:

[0073] Step 1.1: The pure nickel raw material, carbon, and pure titanium are sequentially added into a vacuum induction furnace for melting. After all materials have melted, refining begins. Liquid metal is obtained after refining. The refining power is 570KW, the vacuum degree during refining is less than 5Pa, the refining time is 75min, and the vacuum degree after refining is less than or equal to 0.5Pa.

[0074] Step 1.2: Adjust the temperature of the liquid metal to 1415℃, then quickly add nickel-niobium alloy and nickel-magnesium alloy, then increase the melting power to 550KW, and after the nickel-niobium alloy and nickel-magnesium alloy melt, cast the mixture, and obtain a semi-finished nickel ingot after cooling.

[0075] Using the above process, this embodiment of the invention involves two furnace smeltings, using a Ф570mm cast iron mold; all materials must be cleaned before being loaded into the furnace for smelting, producing two finished nickel ingots with individual weights of 3463kg and 3458kg respectively.

[0076] Step 2: After sawing off the head of the obtained semi-finished nickel ingot, bake it in a resistance furnace and then electroslag remelt it. After cooling, cut off the riser and bottom to obtain the finished nickel ingot. The baking temperature is 450℃ and the baking time is 7h.

[0077] The baked semi-finished nickel ingots are connected end to end and used as remelting electrodes. The remelting electrodes are preheated before use at a temperature of 650°C for 5 hours.

[0078] The electroslag remelting process uses a water-cooled copper-lined crystallizer with dimensions of Φ680 / Φ720×2200mm. The slag is prepared from CaF2, CaO, Al2O3, and MgF2 in a weight ratio of 6:1:2.5:0.5. The slag is thoroughly mixed and baked in a resistance furnace at 450℃ for 8 hours before use. Before electrode installation, the welding quality and concentricity between the electrodes are checked to ensure proper installation. The electrodes are aligned during furnace operation; then the arc is ignited and slag is formed, and remelting begins. The remelting process is automated, with a remelting current of 13500A, a voltage of 67V, and a melting rate of 580Kg / h. When the remelting reaches 100mm from the end of the electrode, feeding begins, with a feeding regime of 11000A current, 60V voltage, and 40min duration. After the electroslag ingot is cooled, the riser and bottom are cut off, and the cooling water outlet temperature is 42℃, resulting in finished nickel ingots with a single weight ≥6t.

[0079] Step 3: The obtained finished nickel ingot is heated to 1040℃ in a 300KW bogie furnace and held for 6 hours. Then, it is hot-forged on an 8000t free forging press. The finished nickel ingot is upset and drawn one by one using the forging press, and then flattened, widened and lengthened into a nickel slab with a thickness of 232mm and a width of 1261mm. The nickel slab is then returned to the furnace and heated to 1020℃ and held for 2 hours. After being taken out of the furnace, it is forged. The final forging temperature is not lower than 800℃. Finally, a nickel slab with a thickness of 116mm and a width of 1282mm is obtained.

[0080] Step 4: The final nickel slab is trimmed, including milling, straightening the edges, and then polishing the surface. The side edges are chamfered at 45° to make the final slab surface smooth and flat, without visible defects such as indentations, cracks, or folds. The nickel slab is then sent to the continuous rolling mill and heated to 1060°C in a walking beam furnace. After holding at that temperature for 110 minutes, the slab is hot rolled in five passes on an R1 four-roll roughing mill. The thickness of the slab changes sequentially to 111mm, 91mm, 72mm, 56mm, 37mm, and 26mm. After rolling, a first semi-finished nickel coil with a thickness of 26mm and a width of 1265mm is obtained.

[0081] Step 5: Place the obtained first semi-finished nickel coil into a hot rolling box and heat it to 970℃. Then, perform precision rolling on the F1-F8 finishing mill to obtain the second semi-finished nickel coil with a thickness of 3.5mm and a width of 1285mm.

[0082] Step 6: The obtained second semi-finished nickel coil is fed into the annealing and pickling line for annealing and pickling. The annealing temperature is 800℃, and the annealing speed, i.e. the traveling speed of the second semi-finished nickel coil, is 5.5m / min. The acid solution is a mixture of 60% HNO3, 1% HF, and deionized water in a volume ratio of 65:5:30. The temperature of the acid solution during pickling is 45℃. Finally, the coil is rolled and bundled to obtain a soft whitened nickel coil.

[0083] Step 7: After trimming the edges of the obtained whitened nickel coil, place it on a 20-roll reversible cold rolling mill. After trimming the edges of the rough coil, roll it into a third semi-finished nickel coil with a thickness of 0.7 mm and a width of 1240 mm through 13 passes and one rolling stroke. The main parameters in this rolling process are: tension 100~320KN, total rolling force 1200~2300T, and rolling speed 55m / s.

[0084] Step 8: The obtained third semi-finished nickel coil is subjected to online bright annealing, specifically on a 1350mm wide strip continuous annealing line. The protective atmosphere is argon, the heat treatment temperature is 750℃, and the annealing speed, i.e. the traveling speed of the third semi-finished nickel coil, is 3m / min. After trimming, a finished nickel coil with a thickness of 0.7mm and a width of 1230mm is obtained. This finished nickel coil is cut into nickel plates and nickel strips according to the user's needs.

[0085] Samples were taken from both ends of the finished nickel coil for analysis, and the test results are shown in Table 7.

[0086] Table 7. Test results of finished nickel coils in Example 2

[0087]

[0088] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength nickel coil, characterized in that, include: Step 1: Pure nickel raw material, nickel-niobium alloy, nickel-magnesium alloy, and smelting additives are added to a vacuum induction furnace for vacuum induction melting to obtain semi-finished nickel ingots. The smelting additives are pure titanium and carbon, and are added based on the total weight of the pure nickel raw material in the following weight ratios: pure titanium 0.01–0.05%, carbon 0.02–0.03%; the added weight of the nickel-niobium alloy is 0.03–0.3% of the total weight of the pure nickel raw material; the added weight of the nickel-magnesium alloy is 0.017–0.17% of the total weight of the pure nickel raw material; the chemical composition weight ratio of the nickel-niobium alloy is: Ni 50%, Nb 50%; the chemical composition weight ratio of the nickel-magnesium alloy is: Ni 70%, Mg 30%. Step 1 includes: Step 1.1: The pure nickel raw material, carbon, and pure titanium are sequentially added into a vacuum induction furnace for melting. After all materials have melted, refining begins. Liquid metal is obtained after refining. The refining power is 550-580KW, the vacuum degree during refining is less than 5Pa, the refining time is 60-80min, and the vacuum degree after refining is less than or equal to 0.5Pa. Step 1.2: Adjust the temperature of the liquid metal to 1400-1420℃, then quickly add nickel-niobium alloy and nickel-magnesium alloy, then increase the melting power to 550KW, and after the nickel-niobium alloy and nickel-magnesium alloy melt, cast the metal, and obtain a semi-finished nickel ingot after cooling. Step 2: The head of the obtained semi-finished nickel ingot is sawn off and baked, then electroslag remelted. After cooling, the riser and bottom are cut off to obtain the finished nickel ingot. The baking temperature is 400-450℃ and the baking time is 6-7 hours. Step 3: Heat the obtained finished nickel ingot to 1020-1050℃, hold for 5.5-6.5 hours, and then perform a first-fire forging to obtain a nickel slab with a thickness of 200-250mm and a width of 1200-1350mm; reheat the nickel slab to 1000-1020℃, hold for 1.5-2.5 hours, and then perform a second-fire forging to obtain a nickel slab with a thickness of 100-120mm, a width of 1250-1380mm, and a height ≥4000mm; wherein the final forging temperature is not lower than 800℃; Step 4: Heat the final nickel slab to 1040-1060℃, hold for 90-110 minutes, and then perform 3-5 passes of hot continuous rolling to obtain the first semi-finished nickel coil with a thickness of 25-30 mm and a width of 1219-1350 mm. Step 5: The obtained first semi-finished nickel coil is heated to 940-970℃ and then precision rolled to obtain a second semi-finished nickel coil with a thickness of 3.0-3.5mm and a width of 1250-1380mm; Step 6: Anneal and pickle the obtained second semi-finished nickel coil to obtain a soft whitened nickel coil; wherein, the annealing temperature is 780~800℃ and the annealing speed is 5~5.5m / min; Step 7: The obtained whitened nickel coil is cold rolled in 6 to 13 passes to obtain a third semi-finished nickel coil with a thickness of 0.6 to 1.5 mm and a width of 1219 to 1350 mm. Step 8: The obtained third semi-finished nickel coil is subjected to online bright annealing to obtain the finished nickel coil; wherein the heat treatment temperature is 730~750℃ and the annealing speed is 3~3.5m / min.

2. The method for preparing high-strength nickel coil according to claim 1, characterized in that, In step 6, the acid solution is a mixture of 60% HNO3, 1% HF and deionized water, and the temperature of the acid solution during pickling is 40-45℃.

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