Method for continuously annealing nickel-plated plate

Abstract

The invention relates to a continuous annealing method for a nickel-plated plate, and belongs to the technical field of nickel-plated plates. The method comprises the steps that a nickel-plated plate is subjected to sectional continuous annealing, so that an alloy layer with the uniform thickness is attached to the surface of the nickel-plated plate, and a nickel-plated annealed plate is obtained; wherein the sectional type continuous annealing comprises continuous annealing of a preheating section, a heating section, a soaking section, a cooling section and an aging section which are sequentially arranged, and the time of the soaking section is adjusted according to the plate surface temperature of the nickel-plated plate in the soaking section. After the nickel-plated plate is continuously annealed, a nickel-iron alloy layer structure with the thickness of 1.5 microns or above can be obtained, the nickel-iron alloy layer has good ductility and compactness and can be subjected to machining such as stamping deformation along with strip steel, the nickel-plated layer cannot fall off, and good machining performance and corrosion resistance are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nickel-plated plates, and particularly relates to a method for continuous annealing of nickel-plated plates. BACKGROUND

[0002] The nickel-plated steel strip product has good electric conductivity and corrosion resistance, and is widely used in the field of power battery manufacturing. With the expansion of the production capacity of cylindrical batteries, the demand for nickel-plated steel strip products for battery shells in the market is increasing. At present, the main process for producing power battery shells on the market in China is the post-nickel plating production method, that is, a steel strip with a thickness of 0.2-0.8 mm is first punched into a battery shell, and then is immersed into an electroplating tank for nickel plating treatment. The battery shell produced by the post-nickel plating process has problems such as uneven nickel layer and high surface porosity, which ultimately affects the corrosion resistance of the battery product and further affects the service life of the battery.

[0003] The pre-nickel plating process is to first plate nickel on a cold-rolled steel plate (i.e., a substrate), and then perform high-temperature alloying treatment, so as to form a nickel-iron alloy layer through mutual diffusion and penetration between the substrate and the nickel layer. This process greatly improves the mechanical properties, corrosion resistance and heat resistance of the plated nickel-plated steel strip, and effectively improves the consistency and safety of the battery after being punched into a battery steel shell. However, the thickness and uniformity of the alloy layer of the pre-nickel plated steel plate are difficult to control, and the performance stability of the nickel-plated plate is poor. SUMMARY

[0004] The present application provides a method for continuous annealing of a nickel-plated plate to solve the technical problem of how to improve the corrosion resistance of the nickel-plated plate.

[0005] In a first aspect, the embodiments of the present application provide a method for continuous annealing of a nickel-plated plate, which comprises:

[0006] The nickel-plated plate is subjected to segmented continuous annealing to attach an alloy layer with uniform thickness on the surface of the nickel-plated plate, so as to obtain a nickel-plated annealed plate. The segmented continuous annealing comprises continuous annealing of a preheating section, a heating section, a soaking section, a cooling section and an aging section arranged in sequence, and the time of the soaking section is adjusted according to the surface temperature of the nickel-plated plate in the soaking section.

[0007] Optionally, the adjusting of the time of the soaking section according to the surface temperature of the nickel-plated plate in the soaking section comprises:

[0008] When the surface temperature T of the nickel-plated plate in the soaking section is 500℃≤T≤550℃, the time t of the soaking section is 600s≤t≤1200s. 均热 均热 When the surface temperature T of the nickel-plated plate in the soaking section is 550℃<T≤600℃, the time t of the soaking section is 1200s

[0009] When the surface temperature T of the nickel-plated plate in the soaking section is 600℃<T≤650℃, the time t of the soaking section is 1200s​均热 for 180s≤t 均热 <600s;

[0010] for 600℃<T≤650℃, the time t of the soaking section is 180s≤t 均热 for 120s≤t 均热 <180s;

[0011] for 650℃<T≤750℃, the time t of the soaking section is 180s≤t 均热 for 30s≤t 均热 <120s.

[0012] Optionally, the thickness is 1.5μm~2.0μm.

[0013] Optionally, the temperature of the aging section is 300℃~450℃, and t 时效 =(0.9~3)t 均热 , t 时效 represents the time of the aging section, in seconds; t 均热 represents the time of the soaking section, in seconds.

[0014] Optionally, the temperature of the preheating section is 250℃~400℃.

[0015] Optionally, the temperature of the heating section is 500℃~750℃.

[0016] Optionally, the cooling speed of the cooling section is 12℃ / s~15℃ / s.

[0017] Optionally, the atmosphere of the continuous annealing includes nitrogen and hydrogen; wherein, the volume fraction of the hydrogen is 2%~5%.

[0018] Optionally, the step of segmentally continuously annealing the nickel-plated plate to attach a uniform thickness of alloy layer on the surface of the nickel-plated plate to obtain a nickel-plated annealed plate further includes:

[0019] sequentially cleaning and drying the nickel-plated plate, the cleaning including alkali cleaning and water cleaning; wherein,

[0020] the process parameters of the alkali cleaning include: alkali concentration of 10g / L~30g / L, alkali temperature of 70℃~90℃, and / or;

[0021] the temperature of the water cleaning is 70℃~90℃, and / or;

[0022] the temperature of the drying is 80℃~120℃.

[0023] Optionally, the nickel-plated plate is subjected to segmented continuous annealing to attach a uniform-thickness alloy layer on the surface of the nickel-plated plate, to obtain a nickel-plated annealed plate, and then further comprising:

[0024] The nickel-plated annealed plate is subjected to flattening, wherein the process parameters of the flattening include: a flattening elongation of 0.8% to 1.5%, and a flattening end-point roughness of 0.6 to 1.5.

[0025] The above technical solution provided by the embodiments of the present application has the following advantages compared with the prior art:

[0026] The nickel-plated plate is subjected to segmented continuous annealing, which includes continuous annealing of a preheating section, a heating section, a soaking section, a cooling section, and an aging section arranged in sequence, and the time of the soaking section is adjusted according to the surface temperature of the nickel-plated plate in the soaking section, so that a uniform-thickness nickel-iron alloy layer is attached on the surface of the nickel-plated plate, the nickel-iron alloy layer has good ductility and compactness, can follow the stamping deformation and other processing of the strip steel, the nickel-plated layer will not fall off, has good processing performance and corrosion resistance, and thus can be well applied to battery cases. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced in the following. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0029] Figure 1 A flowchart of a method for continuous annealing of a nickel-plated plate is provided. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0031] Various embodiments of the present application can exist in a range of forms; it should be understood that the description in a range form is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the range description has disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single values such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated in the present application, it refers to any cited number (fraction or integer) in the indicated range.

[0032] In the present application, the orientation words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings, unless otherwise stated. In addition, in the description of the present application, the terms "include", "contain" and the like mean "include but are not limited to". In the present application, the relationship terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. In the present application, "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the cases of A alone, A and B together, and B alone. Wherein A and B can be singular or plural.

[0033] Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0034] In a first aspect, the embodiments of the present application provide a method for continuous annealing of a nickel-plated plate, Figure 1 A flowchart of a method for continuous annealing of a nickel-plated plate provided by the embodiments of the present application is shown. Please refer to Figure 1 The method comprises the following steps:

[0035] S1, segmenting the nickel-plated plate for continuous annealing to attach an alloy layer with uniform thickness on the surface of the nickel-plated plate, to obtain a nickel-plated annealed plate; wherein the segmenting continuous annealing comprises continuous annealing of a preheating section, a heating section, a soaking section, a cooling section and an aging section arranged in sequence, and adjusting the time of the soaking section according to the surface temperature of the nickel-plated plate in the soaking section.

[0036] In the segmented continuous annealing process, the preheating section: slowly warm up the nickel-plated plate to avoid excessive thermal stress due to sudden heating, thereby preventing plate deformation or other defects, and also preparing for the rapid heating of the subsequent heating section to improve heating efficiency. The heating section: rapidly heats the nickel-plated plate to a temperature condition that can promote the alloying reaction between nickel and iron. In this stage, by controlling the heating speed and temperature, conditions are created for the formation of a uniform nickel-iron alloy layer on the surface of the nickel-plated plate. The soaking section: allows the nickel-plated plate to remain at a specific temperature for a period of time, allowing the nickel-iron alloying reaction to proceed fully to ensure uniform growth of the alloy layer on the surface of the nickel-plated plate to achieve the desired thickness and performance requirements. By adjusting the soaking time according to the plate surface temperature of the nickel-plated plate in the soaking section, it can flexibly adapt to different production situations to ensure the quality stability of the alloy layer. For example, if the plate surface temperature is slightly lower than the set value, the soaking time may need to be appropriately extended to ensure the completion of the alloying reaction; conversely, if the plate surface temperature is too high, the soaking time can be shortened to avoid excessive alloying. The cooling section: cools the nickel-plated plate after soaking to fix the microstructure of the alloy layer and achieve good performance. The cooling speed also affects the performance of the alloy layer. If the cooling speed is too fast, it may generate a large internal stress in the alloy layer, causing cracks or increased brittleness in the alloy layer; if the cooling speed is too slow, it may cause the grains in the alloy layer to grow, reducing its strength and density. Therefore, according to the composition and performance requirements of the alloy layer, the appropriate cooling method and cooling speed should be selected to ensure that the alloy layer has good ductility, density and other performance indicators. The aging section: ages the nickel-plated plate at a certain temperature to further improve the performance of the alloy layer. During the aging process, the microstructure within the alloy will undergo changes such as precipitation strengthening, thereby improving the strength, hardness and corrosion resistance of the alloy layer.

[0037] Through precise control of the segmented continuous annealing process, a uniform thickness of nickel-iron alloy layer can be attached to the surface of the nickel-plated plate. This uniform alloy layer is crucial for improving the performance of the nickel-plated plate, as it can ensure that the alloy layer can uniformly withstand external forces during subsequent processing, avoiding stress concentration and local damage due to uneven thickness of the alloy layer.

[0038] This process gives the nickel-iron alloy layer good ductility and density. Good ductility means that the alloy layer can follow the strip steel in stamping and deformation and other processing without breaking, which is very important for the manufacture of battery shells, because battery shells usually need to undergo complex stamping and forming processes during the production process. Good density can effectively prevent external corrosive media from penetrating into the interior of the nickel-plated plate, improving the corrosion resistance of the nickel-plated plate, thereby extending the service life of the battery shell and ensuring the safety and stability of the battery. Because the alloy layer has good ductility, density and uniform thickness, the nickel-plated plate has good processing performance and corrosion resistance. During the processing, the nickel plating layer will not fall off, and various forming processes can be carried out smoothly, meeting the high-precision manufacturing requirements of the battery shell. At the same time, the excellent corrosion resistance can protect the battery shell from corrosion in the external environment during use, improve the reliability and safety of the battery, and enable it to be better applied in the battery shell field.

[0039] The nickel-plated plate comprises a steel strip and a nickel layer attached to at least a portion of the surface of the steel strip. The steel strip is a low-carbon steel strip with a thickness of 0.2mm to 0.8mm, and the thickness of the single-sided electroplated nickel layer is 3μm to 6μm.

[0040] In some embodiments, adjusting the duration of the soaking section according to the surface temperature of the nickel-plated plate in the soaking section includes:

[0041] When the surface temperature T of the nickel-plated plate in the soaking section is 500°C ≤ T ≤ 550°C, the soaking section time t 均热 600s≤t 均热 ≤1200s;

[0042] When the surface temperature T of the nickel-plated plate in the soaking section is 550°C <T≤600℃,所述均热段的时间t 均热 180s≤t 均热 <600s;

[0043] When the surface temperature T of the nickel-plated plate in the soaking section is 600°C <T≤650℃,所述均热段的时间t 均热 120s≤t 均热 <180s;

[0044] When the surface temperature T of the nickel-plated plate in the soaking section is 650°C <T≤750℃,所述均热段的时间t 均热 30s≤t 均热 <120s.

[0045] 500℃≤T≤550℃,600s≤t 均热≤1200s: In this temperature range, the surface temperature of the nickel-plated plate is relatively low. Lower temperature means that the rate of nickel-iron alloying reaction is relatively slow. In order to make the alloying reaction proceed sufficiently to form a uniform and quality- required nickel-iron alloy layer on the surface of the nickel-plated plate, a longer soaking time is required, ranging from 600 seconds to 1200 seconds. By a longer soaking time, enough time is given to the alloying reaction to complete, ensuring that the thickness and performance of the alloy layer meet the expectations. 550℃ < T≤ 600℃, 180s≤t 均热 <600s: When the temperature rises to this range, due to the increase of temperature, the rate of nickel-iron alloying reaction accelerates. Higher temperature provides more energy for the alloying reaction, enabling the reaction to achieve better results in a relatively short time. Therefore, the soaking time is correspondingly shortened, from 180 seconds to less than 600 seconds, which can ensure that the alloying reaction proceeds sufficiently and improve production efficiency, avoiding energy waste and possible adverse effects such as changes in alloy layer structure caused by excessive soaking. 600℃ < T≤ 650℃, 120s≤t 均热 <180s: As the temperature further rises, the alloying reaction rate further accelerates. At this time, shorter soaking time (120 seconds to less than 180 seconds) is enough to make the alloying reaction achieve the expected effect. The soaking time is continued to be shortened in order to adapt to the characteristics of the reaction proceeding quickly at higher temperatures, preventing problems such as overheating of the alloy layer due to excessive soaking time, affecting its performance and quality. 650℃ < T≤ 750℃, 30s≤t 均热 <120s: In this higher temperature range, the rate of nickel-iron alloying reaction is very fast. Extremely short soaking time (30 seconds to less than 120 seconds) can meet the needs of the alloying reaction. If the soaking time is too long, it may cause excessive reaction of the alloy layer, resulting in deterioration of the structure and performance. Therefore, in this temperature range, shorter soaking time is used to ensure the quality and performance of the alloy layer.

[0046] In some embodiments, the thickness is 1.5 μm to 2.0 μm.

[0047] The thickness of the alloy layer can be 1.5 μm to 2.0 μm, which can effectively block the contact of external corrosive medium with the substrate of the nickel-plated plate. The appropriate thickness ensures that the alloy layer has sufficient density and continuity, forming a reliable protective barrier. For example, in the application scenario of battery shell, the electrolyte and other substances inside the battery have certain corrosive properties. The alloy layer with such thickness can resist corrosion for a long time and prevent the nickel-plated plate from being eroded, thereby protecting the safety and stability of the battery and prolonging the service life of the battery. The alloy layer with a thickness of 1.5 μm to 2.0 μm helps to maintain the good mechanical properties of the nickel-plated plate. For example, the thickness can be 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, etc.

[0048] In some embodiments, the temperature of the aging section is 300 °C to 450 °C, and satisfies t 时效 = (0.9-3) t 均热 , t 时效 represents the time of the aging section, in seconds; and t 均热 represents the time of the soaking section, in seconds.

[0049] The temperature of the aging section can be 300 °C to 450 °C, and the atoms inside the alloy have certain activity, which can slowly diffuse and rearrange. Avoiding the alloy layer from grain growth, organization coarsening and other adverse phenomena due to too high temperature, thereby maintaining the good toughness and ductility of the alloy layer. t 时效 = (0.9-3) t 均热 The relationship between the aging time and the soaking time is set to ensure the sufficiency and moderation of the aging treatment. The soaking section is mainly to complete the nickel-iron alloying reaction, so that the alloy layer grows uniformly on the surface of the nickel-plated plate; and the aging section is to further strengthen and optimize the performance of the alloy layer. The appropriate aging time allows the alloy layer to have sufficient time for organization change and performance improvement. Therefore, the reasonable ratio of aging time to soaking time can make the alloy layer have good comprehensive performance.

[0050] In some embodiments, the temperature of the preheating section is 250 °C to 400 °C.

[0051] The temperature of the preheating section can be 250 °C to 400 °C, which makes the temperature distribution inside the plate more uniform, thereby effectively reducing the generation of thermal stress and preparing for the subsequent heating process. The appropriate preheating can make the nickel atoms and iron atoms more easily diffuse and react with each other at a higher temperature in the subsequent process, which is helpful to form a uniform nickel-iron alloy layer. For example, the temperature of the preheating section can be 250 °C, 300 °C, 350 °C, 400 °C, etc.

[0052] In some embodiments, the temperature of the heating section is 500 °C to 750 °C.

[0053] The temperature of the heating section can be 500-750°C, so that the nickel atoms and iron atoms have enough energy to diffuse and react rapidly and form a uniform nickel-iron alloy layer in a short time. For example, the temperature of the heating section can be 550°C, 660°C, 665°C, 670°C, 675°C, etc.

[0054] In some embodiments, the cooling speed of the cooling section is 12-15°C / s.

[0055] The cooling speed of the cooling section can be 12-15°C / s, so that the alloy layer forms a suitable microstructure during cooling, and the nickel-plated plate has a relatively uniform alloy layer microstructure and performance after cooling. For example, the cooling speed of the cooling section can be 12°C / s, 13°C / s, 14°C / s, 15°C / s, etc.

[0056] In some embodiments, the atmosphere of the continuous annealing includes nitrogen and hydrogen; wherein the volume fraction of the hydrogen is 2-5%.

[0057] In order to prevent the strip from being oxidized during annealing, the annealing furnace is filled with a nitrogen-hydrogen mixed protective gas, the hydrogen content can be 2-5%, and the oxygen content is controlled to be less than 20 ppm. For example, the volume fraction of the hydrogen can be 2%, 3%, 4%, 5%, etc.

[0058] In some embodiments, the nickel-plated plate is subjected to the segmented continuous annealing to attach a uniform thickness of the alloy layer on the surface of the nickel-plated plate, thereby obtaining a nickel-plated annealed plate, and the method further comprises:

[0059] The nickel-plated plate is sequentially cleaned and dried, the cleaning includes alkaline cleaning and water cleaning; wherein,

[0060] The process parameters of the alkaline cleaning include: the alkali concentration is 10-30 g / L, the alkali temperature is 70-90°C, and / or;

[0061] The water cleaning temperature is 70-90°C, and / or;

[0062] The drying temperature is 80-120°C.

[0063] The surface of the nickel-plated plate is subjected to alkaline washing and water washing, the main purpose is to remove the oil and impurities on the surface of the strip steel, the strip steel is dried by using the squeezing roller and heating air after leaving the cleaning tank, and finally the clean strip steel is obtained. The process parameters of alkaline washing include: the concentration of the alkali solution is 10 g / L-30 g / L, the temperature of the alkali solution can be 70℃-90℃, the temperature of water washing can be 70℃-90℃, and the temperature of drying after cleaning can be 80℃-120℃. Generally, the alkali solution can be sodium hydroxide (NaOH). For example, the concentration of the alkali solution can be 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, etc.; the temperature of the alkali solution can be 70℃, 75℃, 80℃, 85℃, 90℃, etc.; the temperature of water washing can be 70℃, 75℃, 80℃, 85℃, 90℃, etc.; and the temperature of drying can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, etc. The drying can be hot air drying, and the air speed can be 4 m / s-5 m / s.

[0064] In some embodiments, the nickel-plated plate is subjected to segmented continuous annealing to attach an alloy layer with uniform thickness on the surface of the nickel-plated plate, to obtain a nickel-plated annealed plate, and then further comprising:

[0065] The nickel-plated annealed plate is subjected to flattening; wherein the process parameters of the flattening include: flattening elongation of 0.8%-1.5%, and flattening end point roughness of 0.6 μm-1.5 μm.

[0066] In order to improve the stamping performance of the nickel-plated plate, eliminate the yield platform, and change the surface roughness of the strip steel, the flattened strip steel after alloying is subjected to flattening treatment, the flattening elongation can be 0.8%-1.5%, and the flattening end point roughness Ra can be 0.6 μm-1.5 μm. For example, the flattening elongation can be 0.8%, 0.9%, 1.0%, 1.2%, 1.3%, 1.4%, 1.5%, etc.; and the flattening end point roughness can be 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc.

[0067] The method for continuous annealing of the nickel-plated plate provided by the embodiments has the following advantages:

[0068] 1. High quality alloy layer: Through the segmented continuous annealing process, including the reasonable setting of preheating section, heating section, soaking section, cooling section and aging section, a uniform thickness (1.5-2.0 pm) nickel-iron alloy layer can be attached to the surface of the nickel-plated plate. The soaking section adjusts the time accurately according to the plate surface temperature, ensures that the alloying reaction proceeds fully, so that the alloy layer has good ductility and density, which can follow the steel sheet for stamping deformation and other processing, and can effectively prevent the nickel-plated layer from falling off, meeting the needs of subsequent processing and application.

[0069] 2. Excellent performance: The alloy layer of the nickel-plated plate prepared by the method has good comprehensive performance. In terms of corrosion resistance, the alloy layer with appropriate thickness and structure can effectively block the external corrosive medium, and is suitable for applications such as battery shell which require high corrosion resistance; in terms of mechanical properties, good ductility, certain strength and hardness ensure the stability and reliability of the nickel-plated plate during processing.

[0070] 3. Strong process flexibility and controllability: The soaking section can flexibly adjust the time according to the plate surface temperature of the nickel-plated plate, and the time of the aging section is related to the time of the soaking section (t 时效 = (0.9-3) t 均热 ), and the temperature and speed parameters of each stage (preheating section, heating section, cooling section, etc.) have a clear and reasonable setting range. This accurate process parameter control method can adapt to nickel-plated plates with different initial states, ensuring that stable quality products can be produced under various conditions, improving the flexibility and controllability of the process.

[0071] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods not specified in the following examples are generally determined according to the national standards. If there is no corresponding national standard, the international standard, the conventional condition or the condition suggested by the manufacturer is used.

[0072] The continuous annealing method of the nickel-plated plate provided in the embodiments of the present application is shown in Table 1, and the process parameters of the alkali washing, water washing and drying of the nickel-plated plate are shown in Table 2.

[0073] Table 1 Process parameters of alkali washing, water washing and drying of nickel-plated plate

[0074]

[0075] Table 2 Process parameters of continuous annealing and leveling

[0076]

[0077] The salt spray resistance of the nickel-plated plate was evaluated according to GB / T 10125-2021 "Salt Spray Test for Artificial Atmosphere Corrosion Test" and GB T6461-2002 "Evaluation of Samples and Test Pieces after Corrosion Test of Metal and Other Inorganic Coatings on Metal Substrate", and the neutral salt spray test time was 2 h. The performance test results of the nickel-plated plate under the above process conditions are shown in Table 3.

[0078] Table 3 Performance of nickel-plated plate

[0079]

[0080] From the comparison of the process parameter control and finished product performance detection of Examples 1-3 and Comparative Examples 1-2, it can be concluded that the alloyed coating product obtained by the examples of the present application has good processing performance and corrosion resistance, and meets the corrosion resistance condition of 2 h corrosion level 9 or above in the salt spray test. At the same time, the yield strength of the finished product obtained by the leveling process of the examples of the present application is between 250 Mpa and 450 Mpa, the yield platform is completely eliminated, and the product has good stamping processing performance.

[0081] The one or more technical solutions in the examples of the present application have at least the following technical effects or advantages:

[0082] (1) By adopting the control strategy of matching the temperature of different soaking sections with the time of different soaking sections, the surface alloy layer of the nickel-plated plate is stably controlled, and the corrosion resistance of the nickel-plated plate is improved;

[0083] (2) After continuous annealing, a nickel-iron alloy layer structure of 1.5 μm or more can be obtained, the nickel-iron alloy layer has good ductility and compactness, and can follow the stamping deformation and other processing of the steel strip, the nickel-plated layer will not fall off, and has good processing performance and corrosion resistance.

[0084] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A method for continuous annealing of a nickel-plated plate, the method comprising: The nickel-plated plate is subjected to segmented continuous annealing to attach an alloy layer of uniform thickness to the surface of the nickel-plated plate to obtain a nickel-plated annealed plate; wherein the segmented continuous annealing includes: continuous annealing of a preheating section, a heating section, a soaking section, a cooling section and an aging section arranged in sequence, and the soaking section time is adjusted according to the plate surface temperature of the nickel-plated plate in the soaking section.

2. The method according to claim 1, characterized in that The step of adjusting the duration of the soaking section according to the surface temperature of the nickel-plated plate in the soaking section comprises: When the surface temperature T of the nickel-plated plate in the soaking section is 500°C ≤ T ≤ 550°C, the soaking section time t 均热 600s≤t 均热 ≤1200s; When the surface temperature T of the nickel-plated plate in the soaking section is 550°C < T ≤ 600°C, the time t of the soaking section 均热 is 180s ≤ t 均热 < 600s; When the surface temperature T of the nickel-plated plate in the soaking section is 600°C < T ≤ 650°C, the time t of the soaking section 均热 is 120s ≤ t 均热 < 180s; When the surface temperature T of the nickel-plated plate in the soaking section is 650°C < T ≤ 750°C, the time t of the soaking section 均热 is 30s ≤ t 均热 < 120s.

3. The method according to claim 1, characterized in that The thickness is 1.5 μm to 2.0 μm.

4. The method according to claim 1, wherein The temperature of the aging stage is 300℃~450℃, and meets t 时效 =(0.9~3)t 均热 , t 时效 Indicates the time of the aging period, in seconds; t 均热 Indicates the time of the soaking period, in seconds.

5. The method according to claim 1, wherein The temperature of the preheating section is 250°C to 400°C.

6. The method according to claim 1, characterized in that The temperature of the heating section is 500°C to 750°C.

7. The method according to claim 1, characterized in that The cooling speed of the cooling section is 12°C / s to 15°C / s.

8. The method according to claim 1, characterized in that The continuous annealing atmosphere includes nitrogen and hydrogen; wherein the volume fraction of the hydrogen is 2% to 5%.

9. The method according to claim 1, characterized in that The nickel-plated plate is subjected to segmented continuous annealing to attach an alloy layer of uniform thickness to the surface of the nickel-plated plate to obtain a nickel-plated annealed plate, and the method further comprises: The nickel-plated plate is sequentially cleaned and dried, wherein the cleaning comprises alkali cleaning and water washing; wherein, The process parameters of the alkali washing include: alkali solution concentration of 10g / L to 30g / L, alkali solution temperature of 70°C to 90°C, and / or; The water washing temperature is 70°C to 90°C, and / or; The drying temperature is 80°C to 120°C.

10. The method according to claim 1, characterized in that The nickel-plated plate is subjected to segmented continuous annealing to attach an alloy layer of uniform thickness to the surface of the nickel-plated plate to obtain a nickel-plated annealed plate, and then further comprises: The nickel-plated annealed plate is flattened; wherein the process parameters of the flattening include: a flattening elongation of 0.8% to 1.5%, and a flattening end point roughness of 0.6 μm to 1.5 μm.

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