Wide-width and extremely thin specification tinplate and a method for manufacturing the same

Abstract

The present application relates to a kind of wide thin gauge tinplate and its preparation method, the chemical composition of tinplate base material is C:0.0010%~0.0014%, Si≤0.02%, Mn:0.09%~0.14%, P≤0.015%, S≤0.004%, N:0.0146%~0.0158%, B:0.0038%~0.0049%, Alt:0.015%~0.045%, Mg:0.0012%~0.0024%, Ti:0.077%~0.094%;The rest is Fe and impurity.The wide thin gauge (thickness 0.08~0.18mm, width ≥2000mm) tinplate produced by the present application has good organization and performance uniformity, and the alloy cost of tinplate base material is low;At the same time, the problems of quality defects such as breakage, hole, bright band, etc. in the cold rolling annealing process of conventional production process are solved.

Description

Technical Field

[0001] This invention relates to the field of tinplate production technology, and in particular to a wide-width, ultra-thin tinplate and its preparation method. Background Technology

[0002] Tinplate (tin-plated sheet) is a cold-rolled low-carbon steel sheet and strip plated with pure tin on both sides. As a high-value-added cold-rolled coated steel, it features corrosion resistance, non-toxicity, high strength, and good ductility. It is widely used in can manufacturing, packaging materials, stamping containers, and other industries. Based on different tempering grades, it can be divided into five types from MRT1 to MRT5, and based on the annealing process, it can be divided into CA and BA materials. The thickness of finished tinplate is generally in the range of 0.20–0.5 mm, while thinner specifications (thickness ≤ 0.19 mm) of tinplate are mostly imported.

[0003] With the development of lightweight application technologies, the demand for thin-gauge tinplate materials is growing rapidly. The thickness of the hot-rolled base material used for thin-gauge tinplate is generally between 1.8 and 2.48 mm, and the cold rolling reduction rate can reach over 90%. The cold rolling process generally adopts single-stand rolling or continuous rolling mill. Due to the advantages of continuous annealing (CA) process, such as uniform annealing temperature, high production efficiency, and high yield, it is more suitable for stamping than the bell annealing (BA) process.

[0004] The steel composition system for tinplate using continuous annealing process includes: (1) adding a certain amount of microalloying elements to the composition of low carbon aluminum killed steel; (2) adding a certain amount of niobium, vanadium and aluminum to the composition of ultra-deep drawing interstitial steel (IF steel) to improve strength, but the alloy cost is high.

[0005] Currently, the main problems in producing ultra-thin (0.08-0.18mm) tinplate are as follows: 1) Due to the large amount of alloying elements added (such as V, Nb and Al elements), the alloy cost is high; 2) The microstructure and properties of the finished product are uneven; 3) The addition of nitrogen gas can easily cause the molten steel to churn; 4) Quality defects such as broken strips, holes and bright strips are prone to occur during cold rolling and annealing.

[0006] Chinese patent application CN119406934A discloses "A wide tinplate steel strip and its preparation method." The method involves hot rolling of a continuously cast billet after heat treatment to obtain an initial steel strip. The reduction of the continuously cast billet during rough rolling accounts for more than 75% of the total reduction. The rough rolling process includes 6 passes and 7 passes for finishing. The single-pass reduction rate for the first 3 passes is more than 17%, the single-pass reduction rate for the last 3 passes is more than 27%, and the single-pass reduction rate for the first 4 passes for finishing is more than 30%. The initial steel strip is then laminar cooled to the coiling temperature and coiled to obtain a wide tinplate steel strip. The preparation method mainly involves the distribution of reduction rates during hot rolling roughing and finishing, as well as the laminar cooling rate and coiling temperature. It does not involve the chemical composition of the steel or the cold rolling annealing process. Furthermore, it does not specify the width of the wide tinplate.

[0007] Chinese patent application CN118638995A discloses a "method for preparing tin-plated sheet". The composition and weight percentage of the tin-plated sheet are: C 0.033-0.048%, Mn 0.18-0.30%, Si≤0.02%, Als 0.02-0.05%, N≤0.0040%, P≤0.015%, S≤0.012%, with the remainder being Fe and unavoidable impurities. The tin-plated sheet has a hardness of HR30T of 54-60. The preparation method includes: heating and hot-rolling a cast billet, controlling the final rolling temperature to roll the heated continuous casting billet in the austenite / ferrite two-phase region; coiling the hot-rolled sheet, controlling the coiling temperature; then pickling and cold rolling to obtain a cold-hardened coil; continuously annealing the cold-hardened coil, controlling the continuous annealing temperature to allow complete recrystallization of the microstructure; and finally tin-plating to obtain the tin-plated sheet. It focuses on hot rolling, cold rolling and continuous annealing, and tin plating processes, but does not mention the performance and uses of the product, which is a conventional method for preparing tin-plated sheets.

[0008] Chinese invention patent CN1174109C discloses an "ultra-thin steel strip for battery casing and its manufacturing method". The battery casing steel is produced using ultra-low carbon Ti-Nb-IF steel. The process includes hot metal pre-desulfurization, converter smelting, ladle refining (RH treatment), continuous casting, hot continuous rolling, coiling, pickling, cold rolling, continuous annealing, slitting and oiling packaging. In order to achieve the interstitial atom-free (IF) state, Ti and Nb composite addition treatment is used to fix C and N interstitial atoms, so that C and Nb combine to form NbC, and N and Ti combine to form TiN. Al in the steel participates in the fixation of N interstitial atoms. The steel contains a large amount of Ti alloy, making the production process difficult to control and resulting in higher production costs. The finished product exhibits significant anisotropy (Δr value) and excessive amounts of Ti and Nb, which can negatively impact the deep-drawing performance of the finished steel sheet. Furthermore, the lack of a leveling process makes it impossible to eliminate or mitigate minor surface defects generated in the previous process, making it difficult to achieve the required sheet shape and roughness and improve the adhesion of the battery casing coating. Summary of the Invention

[0009] This invention provides a wide-width, ultra-thin tinplate and its preparation method. The produced wide-width, ultra-thin tinplate (thickness 0.08-0.18 mm, width ≥ 2000 mm) has good microstructure and performance uniformity, and the alloy cost of the tinplate base material is low. At the same time, it solves the problem of quality defects such as broken strips, holes, and bright strips that are easy to occur during the cold rolling and annealing process in conventional production processes.

[0010] To achieve the above objectives, the present invention employs the following technical solution:

[0011] A wide-width, ultra-thin tinplate substrate has the following chemical composition by mass percentage: C: 0.0010%–0.0014%, Si≤0.02%, Mn: 0.09%–0.14%, P≤0.015%, 0.002%≤S≤0.004%, N: 0.0146%–0.0158%, B: 0.0038%–0.0049%, Alt: 0.015%–0.045%, Mg: 0.0012%–0.0024%, Ti: 0.077%–0.094%; and 0.24≤B / N≤0.34, 0.3≤Mg / S≤1.2; the remainder is Fe and unavoidable impurities, with inclusion size ≤20µm.

[0012] The controlled elements in the chemical composition of tinplate substrate include: Cu≤0.02%, Ni≤0.01%, Mo≤0.01%, Nb≤0.004%, As≤0.01%, Cr+Pb≤0.005wt%, and the total amount of controlled elements does not exceed 0.10%.

[0013] The properties of finished tinplate products are: yield strength 264-284 MPa, tensile strength 362-382 MPa, and elongation after fracture A. 80 ≥40%, r 90 ≥1.8, ≤0.2, inclusion size ≤20µm.

[0014] The thickness of finished tinplate products is 0.08-0.18mm, and the width is ≥2000mm.

[0015] A method for preparing wide-width, ultra-thin tinplate includes the following steps:

[0016] 1) Converter smelting: A combined blowing converter is used for smelting, with nitrogen blowing from the bottom throughout the smelting process; lime and lightly calcined dolomite are used for slag making, and oxygen blowing time is 17-20 min. Before tapping, the molten steel is controlled to have C≤0.05%, O≤500ppm, and slag thickness≤50mm; the tapping temperature is controlled at 1772-1792℃, and the tapping time is controlled at 4-7 min. Slag blocking is used during tapping.

[0017] 2) RH Vacuum Treatment: Nitrogen is used as the lifting gas to feed nitrogen into the molten steel after RH vacuum treatment. The net RH circulation time is 10-14 min, and the post-RH treatment settling time is 15-20 min. Then, manganese nitride cored wire and magnesium alloy cored wire are fed into the molten steel. The feeding rate of manganese nitride cored wire is 4.0-4.3 m / t steel, and the feeding speed is 3.1-3.5 m / s. The feeding speed of magnesium alloy cored wire is 25-30 m / min, and the feeding rate is 0.3-0.5 kg / t steel. The bottom blowing of the ladle is turned off during the wire feeding process.

[0018] 3) Continuous casting: A straight arc continuous casting machine is used for continuous casting, and the superheat is controlled at 36-44℃;

[0019] 4) Hot continuous rolling:

[0020] Heating: The continuously cast billet adopts a hot charging process with a heating temperature of 1262~1282℃;

[0021] Rough rolling: The 3+5 rolling mode is adopted, and the rough rolling start temperature is 1116~1138℃;

[0022] Finishing rolling: 7-stand hot continuous rolling is adopted, with cooling water introduced between stands, and the final rolling temperature is 890~920℃;

[0023] Coiling: A segmented cooling process is adopted. The first stage of cooling is to turn on two sets of cooling water immediately after the steel plate exits the F7 frame for air cooling for 2-3 seconds, and then turn on laminar flow cooling water for cooling. The coiling temperature is 570-600℃.

[0024] Slow cooling: The coiled steel plate is placed in a slow cooling pit for slow cooling treatment for more than 36 hours.

[0025] 5) Pickling: A push-pull type pickling unit is used, and the pickling speed is 152-164 m / min;

[0026] 6) Cold rolling: The steel is rolled using a six-roll reversible rolling mill. Hot-rolled coils with a thickness of 1.8 to 2.48 mm are used and rolled in multiple passes to obtain finished steel plates with a thickness of 0.08 to 0.18 mm.

[0027] 7) Continuous annealing: A continuous annealing unit with ROA function is used. Annealing is carried out sequentially through a soaking zone, a rapid cooling zone, a secondary heating zone, and an aging zone. The soaking zone has a soaking temperature of 724-751℃, the rapid cooling zone cools the temperature to 262-282℃ at a cooling rate of 36-40℃ / s, the secondary heating zone heats the temperature to 425-445℃, and the aging zone cools the temperature to 10-32℃ at a cooling rate of 8.5-9.5℃ / s. After cooling in a quenching tank and drying in a drying oven, the annealed product is removed from the furnace.

[0028] 8) Smoothing: The smoothing elongation rate is controlled between 1.52% and 1.84%;

[0029] 9) Tin plating: An insoluble anodic tin plating production line is used, with a double-sided tin plating amount of 2.5~3.5 / 2.5~3.5 g / m 2 The tin plating speed is 306-326 m / min.

[0030] In step 1), during converter smelting, the weight percentage of molten iron is 51% to 58%, and the weight percentage of scrap steel is 42% to 49%.

[0031] In step 2), the manganese nitride cored wire contains N: 12%–15% and Mn: 83%–84% by mass percentage, with the remainder being impurities.

[0032] In step 3), the fixed length of the continuously cast billet is 10.5m.

[0033] In step 5), four hydrochloric acid pickling tanks are set up, and the HCl mass concentrations in pickling tanks 1# to 4# are 5.2% to 7.2%, 10.2% to 13.4%, 15.4% to 17.2%, and 13.6% to 15.8% respectively.

[0034] In step 8), a double-frame six-roller leveling machine is used for leveling.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1) The alloy cost of tinplate substrate is low, which is conducive to market promotion; Based on ultra-low carbon-manganese steel, this invention adds B, Ti and N as strengthening elements, controls 0.24≤B / N≤0.34, 0.026≤Mg / Alt≤0.16, and adds Mg to control the morphology and size of inclusions, thus obtaining a wide and ultra-thin tinplate substrate with excellent comprehensive performance.

[0037] 2) During converter smelting, the scrap steel ratio reaches 42% to 49%, that is, the green steel smelting process is adopted, and the steel is pure; and by limiting the scrap steel ratio, the carbon dioxide emissions in the tinplate production process can be reduced.

[0038] 3) In order to achieve a reasonable nitrogen content requirement and avoid adding nitrogen gas causing the molten steel to churn, the present invention adopts a wire feeding process to ensure that the manganese nitride cored wire enters the molten steel to a sufficient depth; when feeding wire, the bottom blowing argon gas of the ladle is turned off to reduce the flow force of the molten steel, effectively weaken the slag-metal reaction and the air reaction of the molten steel, and avoid the deterioration of the cleanliness of the molten steel.

[0039] 4) The use of integrated production technology and the small crown C40 of the steel strip during hot rolling can prevent the steel strip from deviating during cold rolling, thereby reducing the risk of cold rolling strip breakage, holes, and bright strip.

[0040] 5) The properties of finished tinplate products are: yield strength 264~284MPa, tensile strength 362~382MPa, elongation after fracture A 80 ≥40%, r 90 ≥1.8, ≤0.2, inclusion size ≤20µm; where, It is the absolute value of Δr, where Δr is the anisotropy difference of the plastic strain ratio, Δr=(r0-2r 45 +r 90 ) / 2; r0, r 45 and r 90 These are the Lankford values ​​relative to the rolling direction of the steel plate at 0°, 45°, and 90°, respectively.

[0041] 6) Tinplate products have good corrosion resistance, certain strength and hardness, good formability and easy welding; the final tinplate (tin-plated sheet) produced is non-toxic and odorless, can prevent iron from dissolving into the packaged items, and has a bright surface; tinplate products have good processing performance, good comprehensive protective performance, and good product structure and performance uniformity.

[0042] 7) After hot continuous rolling, rapid cooling (cooling rate ≥10℃ / s) and a low coiling temperature (570~600℃) are adopted, so that AlN particles do not have time to precipitate during the cooling process and remain in a solid solution state in the hot-rolled steel strip. They only precipitate finely at the subgrain boundaries, which is conducive to obtaining larger and more uniform disc-shaped grains and avoiding the occurrence of mixed crystals with uneven grains. This is beneficial to improving the stamping performance of tinplate. Attached Figure Description

[0043] Figure 1 This is a metallographic photograph of the tinplate substrate prepared in Example 1 of the present invention.

[0044] Figure 2 This describes the inclusion morphology of the tinplate substrate prepared in Example 1 of the present invention. Detailed Implementation

[0045] The tinplate of the present invention, in a wide and ultra-thin specification, has the following chemical composition by mass percentage: C: 0.0010%–0.0014%, Si≤0.02%, Mn: 0.09%–0.14%, P≤0.015%, 0.002%≤S≤0.004%, N: 0.0146%–0.0158%, B: 0.0038%–0.0049%, Alt: 0.015%–0.045%, Mg: 0.0012%–0.0024%, Ti: 0.077%–0.094%; and 0.24≤B / N≤0.34, 0.3≤Mg / S≤1.2; the remainder is Fe and unavoidable impurities, with inclusion size ≤20µm.

[0046] To achieve the goal of pure steel smelting, the elements that are not intentionally added to the tinplate substrate of the present invention, i.e. the controlled elements, include: Cu≤0.02%, Ni≤0.01%, Mo≤0.01%, Nb≤0.004%, As≤0.01%, Cr+Pb≤0.005wt%, and the total amount of controlled elements does not exceed 0.10%.

[0047] The working principle of each chemical element in the tinplate substrate described in this invention is as follows:

[0048] C: In tinplate substrate, ultra-low C content is combined with N and Ti in steel to form ultra-deep drawing interstitial steel; nano-sized Ti (C, N) is beneficial to improve the deep drawing performance and forming performance of wide and ultra-thin tinplate substrate. In this invention, the C content is controlled at 0.0010% to 0.0014%.

[0049] Si: For tinplate substrates, tin plating is required after cold rolling. Low silicon content is beneficial to the adhesion of the coating. In addition, low Si content is also beneficial to improving the surface quality of the steel plate. Therefore, this invention controls the Si content to be ≤0.02%.

[0050] Mn is a commonly used solid solution strengthening element in steel. In order to ensure the microstructure and properties of tinplate substrate, the Mn content is controlled at 0.09% to 0.14% in this invention.

[0051] P is a harmful element in steel. When it grows and aggregates at grain boundaries, it reduces the toughness and formability of tinplate substrates and causes cold brittleness. Therefore, this invention controls the P content to be ≤0.015%.

[0052] S is a harmful element in steel, which can generate MnS inclusions in steel. The lower the content, the better. Therefore, this invention controls the S content to be ≤0.0004%.

[0053] Ti plays a role in fixing C and N in ultra-low carbon steel. Ti is relatively reactive and can exert precipitation strengthening; on one hand, it generates TiN, TiC, and Ti(C,N) particles, with TiN forming preferentially, followed by TiC and Ti(C,N), which is beneficial for improving the strength and toughness of the steel. On the other hand, Ti can improve the cupping and hole-expanding properties of tinplate substrates, thereby improving deep-drawing performance. In this invention, the Ti content is controlled at 0.077%–0.094%.

[0054] Mg: Its main function is to modify inclusions and play a role in oxide metallurgy; by forming spherical and dot-shaped Mn-SOBN-Mg composite compounds, it improves the comprehensive performance of tinplate substrate; in this invention, the Mg content is controlled at 0.0012% to 0.0024%, and at the same time, 0.3≤Mg / S≤1.2 is controlled.

[0055] Nitrogen (N): A certain amount of N combines with Ti, B, and C to form Ti(C,N), BN, etc., playing a role in precipitation strengthening and grain refinement in steel. In tinplate substrates, its main functions include: firstly, increasing the proportion of dissolved N in the total N, effectively promoting N dissolution in the steel; secondly, increasing the absolute content of dissolved N and combined N in the steel; and thirdly, increasing the N content in the BN and AlN precipitates, as well as increasing the proportion of N in the BN and AlN precipitates in the total N, promoting the precipitation of combined N in the steel as BN and AlN phases. Through precipitation strengthening, stable control of the performance of low-cost, high-purity tinplate is achieved. This invention controls the N content to be between 0.0146% and 0.0158%.

[0056] B: In tinplate substrate, B combines with N to form BN particles. BN has good stability and contributes to uniform microstructure and properties. In addition, B segregates at austenite grain boundaries, which can suppress the precipitation of proeutectoid ferrite, allowing carbides to precipitate diffusely in the low-temperature region. In this invention, the B content is controlled at 0.0038% to 0.0049%.

[0057] Alt (AlN) reacts with nitrogen (N) to form AlN, which hinders grain growth and refines the grain size. Under specific processing conditions, it can effectively improve the strength and toughness of tinplate substrates. In this invention, the Alt content is controlled within the range of 0.015% to 0.045%.

[0058] It should be noted that obtaining high-performance tinplate substrates depends not only on the chemical composition design but also on the manufacturing process. Only through reasonable composition design combined with optimized manufacturing processes can the desired microstructure be obtained, thereby effectively improving the deep-drawing performance, formability, and corrosion resistance of the tinplate substrate.

[0059] This invention employs a continuous manufacturing process to produce wide and ultra-thin tinplate. The specific steps are as follows:

[0060] 1. Converter Smelting: A combined blowing converter is used for smelting. The weight ratio of molten iron to scrap steel in the converter is (51%~58%):(42%~49%). Nitrogen is blown from the bottom throughout the smelting process, and lime and lightly calcined dolomite are used for slag formation. The oxygen blowing time is 17~20 min. The final smelting endpoint is controlled with [C] ≤0.05%, [O] ≤500 ppm, and slag thickness ≤50 mm. By controlling the atmosphere inside the converter, the final nitrogen content of the converter is controlled, thereby achieving precise control of the nitrogen content of the finished product. Steel is tapped after the endpoint composition and temperature meet the tapping requirements. The tapping spout should be round, and the tapping time should be controlled at 4~7 min. A sliding plate is used for slag blocking. Slag blocking should be done once during tapping, and slag blocking must be done in the later stages of tapping. The tapping temperature is controlled at 1772~1792℃.

[0061] 2. RH Vacuum Treatment: Deep decarburization is performed using vacuum extraction with nitrogen as the lifting gas. After RH vacuum treatment, the molten steel is fed with wire to increase nitrogen content, and magnesium alloy cored wire is added. The net RH circulation time is 10–14 min, and the post-RH treatment settling time is 15–20 min. Manganese nitride cored wire is fed into the molten steel via a wire feeder at a rate of 4.0–4.3 m / t steel and a feeding speed of 3.1–3.5 m / s. Bottom blowing in the ladle is shut off during the feeding process. The manganese nitride cored wire contains 12%–15% nitrogen and 83%–84% manganese by mass percentage, with the remainder being impurities. The magnesium alloy cored wire is fed at a rate of 25–30 m / min and at a rate of 0.3–0.5 kg / t steel. Through a unique cored wire design and feeding process, nitrogen recovery is improved while suppressing the slag-metal reaction rate during feeding, reducing the problem of increased inclusions.

[0062] 3. Continuous casting: A straight arc continuous casting machine is used for continuous casting, and the superheat is controlled between 36 and 44°C. The preferred length of the continuous casting billet is 10.5m.

[0063] 4. Hot continuous rolling, details are as follows:

[0064] Heating: The continuously cast billet adopts a hot charging process with a heating temperature of 1262–1282℃. The purpose is to fully dissolve the alloying elements in the steel. By limiting the heating temperature, the plasticity of the continuously cast billet can be improved, the deformation resistance can be reduced, and the internal and external temperatures of the billet can be made uniform, which is beneficial for processing and forming. At the same time, the internal structure of the billet can be improved, and the burning loss of the billet can be avoided. If the heating temperature is too high, the degree of oxidation on the surface of the billet will increase; if the heating temperature is too low, the thermoplasticity of the billet will decrease, resulting in surface defects.

[0065] Rough rolling: The 3+5 rolling mode is adopted, and the rough rolling start temperature is 1116~1138℃;

[0066] Finishing rolling: 7-stand hot continuous rolling is adopted, with cooling water introduced between stands, and the final rolling temperature is 890~920℃;

[0067] Coiling: A segmented cooling process is adopted. The first stage of cooling is to turn on two sets of water cooling immediately after the steel plate leaves the F7 frame, followed by air cooling for 2 seconds, and then laminar flow cooling water cooling. The coiling temperature is 570-600℃, which is to ensure the uniformity of the structure and properties.

[0068] Slow cooling: The coiled steel plate is placed in a slow cooling pit for slow cooling treatment, and can only be moved after 36 hours.

[0069] 5. Pickling: A push-pull type pickling unit is used for pickling. To ensure pickling quality, the pickling speed is controlled at 152-164 m / min. It is preferred to have 4 hydrochloric acid pickling tanks. The mass concentration of HCl in pickling tanks 1# to 4# is 5.2%-7.2%, 10.2%-13.4%, 15.4%-17.2%, and 13.6%-15.8% respectively.

[0070] 6. Cold rolling: The process involves rolling hot-rolled coils with a thickness of 1.8 to 2.48 mm using a six-roll reversible rolling mill. After multiple rolling passes, cold-rolled sheets with a thickness of 0.08 to 0.18 mm are obtained.

[0071] 7. Continuous Annealing: A continuous annealing unit with ROA function is adopted (including a soaking section, a rapid cooling section, a secondary heating section, and an aging section). The soaking temperature in the soaking section is 724-751℃. The rapid cooling section cools down to 262-282℃ at a cooling rate of 36-40℃ / s. The secondary heating section heats up to 425-445℃. The aging section cools down to 10-32℃ at a cooling rate of 8.5-9.5℃ / s. After cooling in a quenching tank and drying in a drying oven, the product is taken out of the furnace.

[0072] This invention employs a ROA annealing process, rapidly cooling the high-temperature strip steel to between 262 and 282°C via a rapid cooling rate of 36–40°C / s. This causes lattice distortion in the ferrite crystal structure, which facilitates the nucleation of Fe3C within the ferrite grains. Once carbon reaches supersaturation, the growth of Fe3C after nucleation primarily depends on thermal diffusion (the higher the temperature, the faster the diffusion). A secondary heating process raises the strip steel to an over-aging temperature of 425–445°C, promoting the rapid precipitation of carbon from the supersaturated solid solution and improving the product's resistance to aging and its stamping performance. Furthermore, at the same temperature, as the supersaturation of carbon within the ferrite decreases, it eventually approaches its equilibrium concentration. This invention maintains a cooling rate of 8.5–9.5°C / s during the aging process, causing the carbon saturation to decrease with decreasing temperature. This reduces the final residual solid solution carbon content, weakening the pinning effect of the solid solution carbon on dislocations and further improving the product's resistance to aging and its stamping performance.

[0073] 8. Leveling: The leveling process is carried out using a double-frame six-roller leveling machine, and the leveling elongation rate is controlled between 1.52% and 1.84%.

[0074] 9. Tin plating: Tin plating is performed using an insoluble anodic tin plating production line, with a double-sided tin plating amount of 2.5~3.5 / 2.5~3.5 g / m². 2 The tin plating speed is 306-326 m / min.

[0075] The method for preparing wide-width, ultra-thin tinplate according to this invention involves heating and hot-rolling a continuously cast billet, controlling the final rolling temperature to 890℃~920℃. This allows the heated billet to be rolled in the austenite / ferrite two-phase region, simultaneously increasing the microstructure distortion energy and recrystallization driving force of the billet. The hot-rolled plate undergoes segmented cooling with controlled coiling temperature to reduce recrystallization and refine the grain size. The hot-rolled plate is then pickled and cold-rolled. Pickling removes the iron oxide scale from the surface, resulting in a better surface condition that facilitates control of the plate shape and mechanical properties during subsequent cold rolling. This significantly enhances the recrystallization driving force of the pickled hot-rolled plate during cold rolling, yielding a cold-rolled coil. Cold-rolled steel sheets undergo continuous annealing at controlled temperatures. By rationally designing the continuous annealing process to ensure optimal grain size, microstructure, and mechanical properties, the production efficiency of tinplate is effectively improved while reducing fuel consumption. This process yields tinplate substrates with excellent deep-drawing, drawing, and corrosion resistance. After leveling and tin plating, the resulting tinplate sheet is the finished tinplate product.

[0076] The tinplate products produced by this invention have a thickness of 0.08–0.18 mm and a width ≥2000 mm. The tinplate product properties are: yield strength 264–284 MPa, tensile strength 362–382 MPa, and elongation after fracture A.80 ≥40%, r 90 ≥1.8, ≤0.2, inclusion size ≤20µm.

[0077] The tinplate produced by this invention can be used to make two-piece cans and DR materials, with a beautiful appearance and excellent corrosion resistance.

[0078] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in conjunction with the examples. The following examples are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention, including simple variations or equivalent substitutions, are all within the scope of protection of the present invention.

[0079] Example:

[0080] In this embodiment, the production process of wide-width, ultra-thin tinplate is as follows:

[0081] 1. Steel smelting: Weigh each component raw material according to the formula ratio, and then smelt to obtain molten steel. The chemical composition of molten steel in each embodiment is shown in Table 1.

[0082] Table 1

[0083]

[0084] 2. Refining and continuous casting: After smelting in a top and bottom blowing converter, RH vacuum treatment, and continuous casting, molten steel is prepared into continuously cast billets: The steelmaking and continuous casting process parameters of each embodiment are shown in Table 2.

[0085] Table 2

[0086]

[0087] 3. Hot Continuous Rolling: The continuously cast billet adopts a hot delivery and hot charging process. The roughing rolling adopts a 3+5 rolling mode, and the finishing rolling adopts a 7-stand hot continuous rolling. Cooling water is introduced between the stands; laminar cooling adopts a segmented cooling process; the coiling temperature is 570-600℃, and the coiled steel plate is placed in a slow cooling pit for slow cooling treatment, and can only be moved after 36 hours. The hot continuous rolling process parameters of each embodiment are shown in Table 3.

[0088] Table 3

[0089]

[0090] 4. Pickling, Cold Rolling, Continuous Annealing, Leveling, and Tin Plating: Pickling is performed using a push-pull pickling unit, followed by rolling on a six-roll reversible rolling mill. Hot-rolled coils with a thickness of 1.8–2.48 mm are used, and after multiple rolling passes, cold-rolled steel sheets with a thickness of 0.08–0.18 mm are obtained. Continuous annealing is performed using a continuous annealing unit with ROA (Reverse Oxidation Aspect) function. The leveling process uses a double-stand six-roll leveling machine. Tin plating is performed using an insoluble anode tin plating production line with a tin plating amount of 3.0 / 3.0 g / m³. 2 The tin plating speed is 306-326 m / min. The process parameters of pickling-tin plating in each embodiment are shown in Table 4.

[0091] Table 4

[0092]

[0093] The tinplate product obtained in this embodiment has a thickness of 0.08–0.18 mm and a tin plating weight of 3.0 / 3.0 g / m. 2 .

[0094] Figure 1 The image shows the metallographic structure of the tinplate substrate prepared in Example 1. The microstructure consists of ferrite and cementite (trace amount), with a grain size of 13. Figure 2 The image shows the inclusion morphology of the tinplate substrate prepared in Example 1, with an inclusion size of 8.7 µm.

[0095] The properties of the tinplate product obtained in this embodiment are: yield strength 264-284 MPa, tensile strength 362-382 MPa, and elongation after fracture A. 80 ≥40%, r 90 ≥1.8, ≤0.2, inclusion size ≤20µm. The product performance of each embodiment is shown in Table 5.

[0096] Table 5

[0097]

[0098] Conclusion: This embodiment, through reasonable chemical composition design and hot continuous rolling controlled rolling and cooling, cold rolling annealing and tin plating processes, obtained wide and ultra-thin tinplate products (0.08~0.18mm×2000mm). The products have excellent performance and can completely replace imported products, meeting the market demand of the can manufacturing industry and stamping containers.

[0099] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A wide-bodied, very thin gauge blackplate characterized in that, The chemical composition of the tinplate substrate is, in mass percentage, C: 0.0010% to 0.0014%, Si≤0.02%, Mn: 0.09% to 0.14%, P≤0.015%, 0.002%≤S≤0.004%, N: 0.0146% to 0.0158%, B: 0.0038% to 0.0049%, Alt: 0.015% to 0.045%, Mg: 0.0012% to 0.0024%, Ti: 0.077% to 0.094%; and 0.24≤B / N≤0.34, 0.3≤Mg / S≤1.2; the rest is Fe and inevitable impurities, the inclusion size is ≤20µm; The preparation method of the wide and ultra-thin tinplate comprises the following steps: 1) converter smelting: adopting combined blowing converter smelting, blowing nitrogen gas in the whole smelting process; adopting lime and light-burned dolomite for slagging, the oxygen blowing time is 17-20 min, the C content in molten steel is controlled to be ≤0.05% and the O content is controlled to be ≤500 ppm before tapping, the slag thickness is ≤50 mm; the tapping temperature is controlled to be 1772-1792 ℃, the tapping time is controlled to be 4-7 min, and a slide plate is used for blocking slag during tapping; 2) RH vacuum treatment: adopting nitrogen gas as lifting gas, the molten steel after breaking vacuum of RH vacuum treatment is fed with wire to increase nitrogen; the RH net circulation time is 10-14 min, the RH treatment after static time is 15-20 min; then the nitrogenized manganese cored wire and magnesium alloy cored wire are fed into the molten steel, the feeding amount of the nitrogenized manganese cored wire is 4.0-4.3 m / t of steel, and the wire feeding speed is 3.1-3.5 m / s; the feeding speed of the magnesium alloy cored wire is 25-30 m / min, and the feeding amount is 0.3-0.5 kg / t of steel; the ladle bottom blowing is closed during the wire feeding process; 3) continuous casting: adopting straight-arc type continuous casting machine for continuous casting, and controlling the superheat degree to be 36-44 ℃; 4) hot continuous rolling: heating: adopting hot delivery and hot charging process for the continuous casting blank, and controlling the heating temperature to be 1262-1282 ℃; rough rolling: adopting 3+5 rolling mode, and controlling the rough rolling opening temperature to be 1116-1138 ℃; finish rolling: adopting 7-stand hot continuous rolling, and inputting cooling water between stands, and controlling the finish rolling temperature to be 890-920 ℃; coiling: adopting segmented cooling process, the first stage cooling is carried out by opening 2 groups of cooling water immediately after the steel plate is discharged from the F7 stand, and the laminar cooling water is opened after air cooling for 2-3 s; and the coiling temperature is 570-600 ℃; slow cooling: the steel plate after coiling is sent into a slow cooling pit for slow cooling treatment for more than 36 h; 5) pickling: adopting push-pull type pickling unit, and controlling the pickling speed to be 152-164 m / min; 6) cold rolling: adopting six-stand reversible rolling mill, and adopting the hot-rolled coil plate with a thickness of 1.8-2.48 mm, and after multi-pass rolling, the cold-rolled plate with a thickness of 0.08-0.18 mm is obtained. 7) continuous annealing: using a continuous annealing unit with ROA function, annealing in turn through a soaking section, a rapid cooling section, a secondary heating section and an aging section; wherein the soaking temperature of the soaking section is 724-751℃, the rapid cooling section is cooled at a cooling rate of 36-40℃ / s to 262-282℃, the secondary heating section is heated to 425-445℃, and the aging section is cooled at a cooling rate of 8.5-9.5℃ / s to 10-32℃; then the steel strip is cooled in a quenching tank, dried in a drying oven and discharged from the furnace; 8) skin passing: the skin pass elongation is controlled at 1.52%-1.84%; 9) Tinning: The insoluble anode tinning production line is adopted, and the double-sided tinning amount is 2.5~3.5 / 2.5~3.5g / m 2 , and the tinning speed is 306~326m / min.

2. A wide-bodied, very thin gauge tinplate according to claim 1, wherein The controlled elements in the chemical composition of the tinplate base material include: Cu≤0.02%, Ni≤0.01%, Mo≤0.01%, Nb≤0.004%, As≤0.01%, Cr+Pb≤0.005wt%, and the total amount of the controlled elements is not more than 0.10%.

3. A wide-bodied, very thin gauge tinplate according to claim 1, wherein The finished tinplate has the following properties: yield strength 264-284 MPa, tensile strength 362-382 MPa, elongation A after break 5.5-6.5% 80 ≥ 40%, r 90 ≥ 1.8, ≤ 0.2, inclusion size ≤ 20 pm.

4. A wide-bodied, very thin gauge tinplate according to claim 1, wherein The thickness of the tinplate finished product is 0.08-0.18mm, and the width is ≥2000mm.

5. A wide-bodied, very thin gauge sheet iron as defined in claim 1, wherein In the step 1), the weight percentage of the molten iron is 51%-58% and the weight percentage of the scrap steel is 42%-49% during the converter smelting.

6. A wide-bodied, very thin gauge tinplate as defined in claim 1, characterized in that, In the step 2), the nitrogenized manganese cored wire contains N: 12%-15%, Mn: 83%-84% and the rest is impurities in terms of mass percentage.

7. A wide-bodied, very thin gauge tinplate as defined in claim 1, wherein In the step 3), the continuous casting billet has a fixed length of 10.5m; and in the step 4) of the hot continuous rolling process, the crown C40 of the steel strip is controlled at 5-35μm.

8. A wide-bodied, very thin gauge tinplate according to claim 1, wherein In the step 5), four hydrochloric acid pickling tanks are provided, and the mass concentration of HCl in the 1#-4# pickling tanks is 5.2%-7.2%, 10.2%-13.4%, 15.4%-17.2% and 13.6%-15.8% respectively.

9. A wide-bodied, very thin gauge tinplate according to claim 1, wherein In the step 8), a double-stand six-roll skin pass mill is used for skin passing.

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