Tin plate wide steel strip and preparation method thereof

Abstract

The invention provides a tin plate wide steel strip and a preparation method thereof, and relates to the technical field of steel production, the method comprises the following steps: carrying out heat treatment on a continuous casting billet, and then carrying out hot continuous rolling treatment to obtain an initial steel strip; wherein the rolling reduction of the continuous casting billet in the rough rolling treatment process accounts for more than 75% of the total rolling reduction of the continuous casting billet; 6 passes of rough rolling and 7 passes of finish rolling are carried out in the rough rolling treatment process, the single-pass reduction rate of the first 3 passes of rough rolling is 17% or above, the single-pass reduction rate of the last 3 passes of rough rolling is 27% or above, and the single-pass reduction rate of the first 4 passes of finish rolling is 30% or above; the initial steel strip is subjected to laminar cooling to the coiling temperature and then is coiled, and the wide steel strip of the tin-plated plate is obtained; wherein the laminar cooling speed is 10 DEG C / s or above, and the coiling temperature ranges from 560 DEG C to 600 DEG C. The wide steel strip of the tin-plated plate prepared by the method disclosed by the invention is relatively uniform in structure and mechanical property, and the steel strip is not easy to deviate in the cold rolling process.

Description

Technical Field

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

[0002] Tinplate refers to a cold-rolled low-carbon thin steel plate coated with commercial pure tin on both sides. It combines the strength and formability of steel with the corrosion resistance and beautiful appearance of tin. It has excellent properties such as corrosion resistance, non-toxicity, high strength and good ductility. It is often used in the packaging of food, beverages and medicines.

[0003] At present, only a few companies are able to produce tinplate steel strips with a narrow width (<1000mm), but the production efficiency and cost are relatively high; therefore, it is necessary to develop wider tinplate steel strips. The existing production process of wide tinplate steel strips requires cutting the wide steel strips into narrow steel strips and then cold rolling them. However, the thickness deviation on both sides of the narrow steel strips obtained after cutting is large, which is unstable during the cold rolling process, and the steel strips are prone to deviation, which can easily lead to cold rolling breakage. Moreover, the wide tinplate steel strips produced by the prior art have uneven organization and mechanical properties. For example, the mixed crystal phenomenon of uneven ferrite grain size in the organization of the wide tinplate steel strips causes large performance fluctuations after subsequent cold rolling and tinning, which leads to easy cracking during the stamping and canning process. The mechanical properties of the wide tinplate steel strips are uneven in the width direction. Summary of the invention

[0004] The problem solved by the present invention is at least one of the following problems: the wide tinplate steel strip produced by the prior art has the phenomenon of uneven structure and mechanical properties; the existing production process of wide tinplate steel strip is prone to deviation during the cold rolling process, which easily leads to cold rolling breakage of the steel strip.

[0005] In order to solve the above problems, the present invention provides a method for preparing a tinplate wide steel strip, comprising:

[0006] Step S1, after heating the continuous casting billet that meets the tinplate composition requirements, hot rolling is performed to obtain an initial steel strip; wherein the hot rolling treatment includes rough rolling and finishing rolling, and the reduction amount of the continuous casting billet during the rough rolling process accounts for more than 75% of the total reduction amount of the continuous casting billet during the hot rolling process; 6 rough rolling passes and 7 finishing rolling passes are performed during the rough rolling process, wherein the single-pass reduction rate of the first 3 rough rolling passes is more than 17%, the single-pass reduction rate of the last 3 rough rolling passes is more than 27%, and the single-pass reduction rate of the first 4 finishing rolling passes is more than 30%; during the hot rolling process, the convexity C40 of the steel strip is controlled to be 7-47μm; the starting rolling temperature of the rough rolling process is 1100-1200℃, and the final rolling temperature is 1050-1150℃;

[0007] Step S2, laminar cooling the initial steel strip to a coiling temperature and then coiling it to obtain a wide tinplate steel strip; wherein the width of the wide tinplate steel strip is 1000-1630 mm, the laminar cooling rate is above 10°C / s, and the coiling temperature is 560-600°C.

[0008] Optionally, in step S1, the reduction ratio of each pass of the first three rough rolling passes is 18-20%, the reduction ratio of each pass of the last three rough rolling passes is 28-29%, and the reduction ratio of each pass of the first four finishing rolling passes is 34-48%.

[0009] Optionally, during the finishing process, the reduction ratio of each of the last three finishing passes is 13-33%, and decreases in order from the front to the back, and the sum of the reduction ratios of each of the last three finishing passes is more than 45%.

[0010] Optionally, during the finishing rolling process, the single-pass reduction rate of the seventh finishing rolling is 13-14%.

[0011] Optionally, in the step S1, the convexity C40 of the steel strip is controlled to be 26-31 μm during the hot rolling process.

[0012] Optionally, in step S1, the start rolling temperature of the finish rolling treatment is 1000-1050°C, and the final rolling temperature is 860-900°C.

[0013] Optionally, in step S1, the furnace exit temperature of the heat treatment is 1170-1240°C, the furnace time is 150-200 minutes, and the soaking time is 22-40 minutes.

[0014] Optionally, the thickness of the tinplate wide steel strip is 2.5-5.0 mm.

[0015] The present invention also provides a tinplate wide steel strip, which is manufactured by the method for preparing the tinplate wide steel strip as described above.

[0016] Optionally, the components of the tinplate wide steel strip include, by weight percentage: C: 0.052-0.075%, Si: 0-0.025%, Mn: 0.27-0.45%, P: 0-0.015%, S: 0-0.012%; Als: 0.020-0.055%, N: 0-0.0045%, Cu: 0-0.035%, Ni: 0-0.035%, Cr: 0-0.035%, Mo: 0-0.025%, As: 0-0.010%, and the balance is Fe and unavoidable impurities.

[0017] Compared with the prior art, in the present invention, by controlling the ratio of the reduction amount of the continuous casting billet during the rough rolling process to the total reduction amount of the continuous casting billet during the hot rolling process to be above 75%, the continuous casting billet is deformed by a large reduction amount during the rough rolling process, ensuring that the continuous casting billet can obtain sufficient deformation in the width direction, thereby reducing the difference in the structure in the width direction and improving the uniformity of the structure; in addition, in the present invention, the single-pass reduction rate of the first 3 rough rolling passes is controlled to be above 17%, the single-pass reduction rate of the last 3 rough rolling passes is controlled to be above 27%, and the single-pass reduction rate of the first 4 finishing rolling passes is above 30%, so that the single-pass reduction amount in the rough rolling process and the single-pass reduction amount in the first 4 finishing rolling passes are both large, which is beneficial to the closure of microscopic defects, making the stress distribution in the steel strip more uniform, reducing stress concentration, and improving the uniformity of the mechanical properties of the steel strip. In the present invention, since the temperature of the rough rolling process is controlled at above 1050°C, it can ensure that the rough rolling deformation is within the recrystallization temperature range, so that the structure is refined and homogenized through recrystallization. In addition, in the present invention, rapid cooling (above 10°C / s) and a lower coiling temperature (560-600°C) are used after hot rolling, so that AlN particles do not have time to precipitate during the cooling process, and AlN particles remain in a solid solution state in the hot-rolled steel strip. AlN is only finely precipitated on the subgrain boundaries, which is conducive to obtaining larger and more uniform pie-shaped grains, avoiding the occurrence of mixed crystals with uneven grain sizes, and is conducive to improving the stamping performance of tinplate. In addition, in the present invention, the convexity C40 of the steel strip is made smaller during the hot rolling process, which can avoid the steel strip from running off during the cold rolling process, thereby reducing the risk of cold rolling breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process of preparing a wide tinplate steel strip according to an embodiment of the present invention;

[0019] Figure 2 The metallographic structure picture of the tinplate wide steel strip prepared in Example 1 is taken. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0022] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more. In the present invention, the wide steel strip for tinplate refers to the wide steel strip used to produce tinplate.

[0023] It should be noted that, assuming that the thickness of the continuous casting billet before a certain rolling pass is M0, and the thickness is reduced to M1 after the rolling pass, the single-pass reduction rate = (M0-M1) / M0. For example, the thickness of the continuous casting billet before the first rough rolling pass is 100 mm, the thickness after the first rough rolling pass is 80 mm, and the thickness after the second rough rolling pass is 60 mm. Then, the single-pass reduction rate of the first rough rolling pass = (100-80) / 100, and the single-pass reduction rate of the second rough rolling pass = (80-60) / 80.

[0024] like Figure 1 As shown, a method for preparing a wide tinplate steel strip provided by an embodiment of the present invention comprises:

[0025] Step S1, after heating the continuous casting billet that meets the tinplate composition requirements, hot rolling is performed to obtain an initial steel strip; wherein the hot rolling treatment includes rough rolling and finishing rolling, and the reduction amount of the continuous casting billet during the rough rolling process accounts for more than 75% of the total reduction amount of the continuous casting billet during the hot rolling process; 6 rough rolling passes and 7 finishing rolling passes are performed during the rough rolling process, wherein the single-pass reduction rate of the first 3 rough rolling passes is more than 17%, the single-pass reduction rate of the last 3 rough rolling passes is more than 27%, and the single-pass reduction rate of the first 4 finishing rolling passes is more than 30%; during the hot rolling process, the convexity C40 of the steel strip is controlled to be 7-47μm; the starting rolling temperature of the rough rolling process is 1100-1200℃, and the final rolling temperature is 1050-1150℃;

[0026] Step S2, laminar cooling the initial steel strip to a coiling temperature and then coiling it to obtain a wide tinplate steel strip; wherein the width of the wide tinplate steel strip is 1000-1630 mm, the laminar cooling rate is above 10°C / s, and the coiling temperature is 560-600°C.

[0027] In the embodiment of the present invention, by controlling the ratio of the reduction amount of the continuous casting billet during the rough rolling process to the total reduction amount of the continuous casting billet during the hot rolling process to be above 75%, the continuous casting billet is deformed by a large reduction amount during the rough rolling process, ensuring that the continuous casting billet can obtain sufficient deformation in the width direction, thereby reducing the difference in the organization in the width direction and improving the uniformity of the organization; in addition, in the embodiment of the present invention, the single pass reduction rate of the first three rough rolling passes is controlled to be above 17%, the single pass reduction rate of the last three rough rolling passes is controlled to be above 27%, and the single pass reduction rate of the first four finishing rolling passes is above 30%, so that the single pass reduction amount during the rough rolling process and the single pass reduction amount of the first four finishing rolling passes are both large, which is conducive to the closure of micro defects, making the stress distribution in the steel strip more uniform, reducing the stress concentration phenomenon, and thus improving the uniformity of the mechanical properties of the steel strip. In the embodiment of the present invention, since the temperature of the rough rolling process is controlled to be above 1050°C, it can be ensured that the rough rolling deformation is within the recrystallization temperature range, so that the organization is refined and uniformed through recrystallization. In addition, in the embodiment of the present invention, rapid cooling (above 10°C / s) and a relatively low coiling temperature (560-600°C) are used after hot rolling, so that the AlN particles do not have time to precipitate during the cooling process, and the AlN particles remain in a solid solution state in the hot-rolled steel strip. AlN is only finely precipitated on the subgrain boundaries, which is conducive to obtaining larger and more uniform pancake-shaped grains, avoiding the appearance of mixed crystals with uneven grain sizes, and is conducive to improving the stamping performance of tinplate. In addition, in the embodiment of the present invention, the convexity C40 of the steel strip is made smaller during the hot rolling process, which can avoid the steel strip from running off during the cold rolling process, thereby reducing the risk of cold rolling strip breakage.

[0028] In some embodiments of the present invention, in step S1, the reduction ratio of each of the first three rough rolling passes is 18-20%, and the reduction ratio of each of the last three rough rolling passes is 28-29%.

[0029] In some embodiments of the present invention, during the finishing process, in step S1, the single pass reduction rate of the first 4 finishing passes is 34-48%, and the single pass reduction rate of the last 3 finishing passes is 13-33%, and they decrease in order from front to back, the sum of the single pass reduction rates of the last 3 finishing passes is more than 45%, and the single pass reduction rate of the 7th finishing pass is 13-14%. In the embodiment of the present invention, the single pass reduction rate of the first 4 finishing passes is set higher in order to reduce the structural unevenness in the width direction. The single pass reduction rate of the first 4 finishing passes is gradually reduced to improve the plate shape. The sum of the single pass reduction rates of the last 3 finishing passes is controlled to be more than 45% in order to accumulate sufficient structural defects and phase change driving force to facilitate grain refinement.

[0030] In some embodiments of the present invention, in the step S1, the convexity C40 of the steel strip is controlled to be 26-31 μm during the hot rolling process.

[0031] In some embodiments of the present invention, in the step S1, the start rolling temperature of the finish rolling process is 1000-1050°C, and the final rolling temperature is 860-900°C.

[0032] In some embodiments of the present invention, in step S1, the furnace temperature of the heat treatment is 1170-1240°C, the furnace time is 150-200 minutes, and the soaking time is 22-40 minutes. The soaking time is controlled to be 22-40 minutes to ensure the uniformity of the temperature of the continuous casting billet and prevent austenite coarsening.

[0033] In some embodiments of the present invention, the thickness of the tinplate wide steel strip is 2.5-5.0 mm.

[0034] The present invention also provides a tinplate wide steel strip, which is manufactured by the method for preparing the tinplate wide steel strip as described above.

[0035] In some embodiments of the present invention, the components of the tinplate wide steel strip include, by weight percentage: C: 0.052-0.075%, Si: 0-0.025%, Mn: 0.27-0.45%, P: 0-0.015%, S: 0-0.012%, Als: 0.020-0.055%, N: 0-0.0045%, Cu: 0-0.035%, Ni: 0-0.035%, Cr: 0-0.035%, Mo: 0-0.025%, As: 0-0.010%, and the balance is Fe and unavoidable impurities. Thus, the strength, hardness and punching performance of the tinplate wide steel strip meet the use requirements.

[0036] The chemical composition of the tinplate wide steel strip provided in this embodiment is designed based on the following:

[0037] 1) Determination of C content

[0038] When the C content increases, the strength and hardness of the steel will increase, which will deteriorate the punching performance of the steel. A high C content will also reduce the corrosion resistance of the steel. Therefore, the carbon content should not be too high. In this embodiment, the C content is controlled in the range of 0.052-0.075%.

[0039] 2) Determination of Mn content

[0040] Mn is dissolved into ferrite to cause solid solution strengthening, thereby increasing the strength of the steel and combining with sulfur in the steel to eliminate the harmful effects of sulfur in the steel. In this embodiment, the Mn content is controlled at 0.27-0.45%.

[0041] 3) Determination of P content

[0042] P is a harmful element in steel. When the P content in steel is high, the cold brittleness of the steel will be increased and the plasticity of the steel will be reduced. Therefore, the phosphorus content should be strictly controlled. In this embodiment, the P content is controlled at 0-0.015%.

[0043] 4) Determination of S content

[0044] S is a harmful element in steel, which can cause hot brittleness of steel. The increase of sulfur content in steel increases the content of sulfide inclusions, which deteriorates the punching performance of steel. The sulfur content should be strictly controlled. In this embodiment, the S content is controlled at 0-0.015%.

[0045] 5) Determination of Als content

[0046] Als reduces dissolved oxygen in steel on the one hand, and secondly combines with nitrogen to form dispersed AlN, thereby improving the aging properties of steel. In this embodiment, the Als content is controlled at 0.020-0.055%.

[0047] 6) Determination of N content

[0048] Nitrogen is a harmful element in steel. It will form nitrides in steel and dissolve in cementite, causing changes in the properties of steel during deformation aging, increasing the strength and hardness of steel and reducing toughness. In order to reduce the adverse effects of nitrogen, the nitrogen content is reduced as much as possible. In this embodiment, the nitrogen content is controlled at 0-0.0045%.

[0049] The present invention is further described below in conjunction with specific embodiments.

[0050] Example 1

[0051] 1.1. A continuous casting billet with a width of 1540 mm and a thickness of 230 mm is subjected to a heat treatment, wherein the furnace temperature of the heat treatment is 1218°C, the furnace time is 160 min, and the soaking time is 40 min; wherein the components of the continuous casting billet, by weight percentage, include: C: 0.052%, Si: 0.012%, Mn: 0.36%, P: 0.010%, S: 0.010%; Als: 0.025%, N: 0.0025%, Cu: 0.025%, Ni: 0.020%, Cr: 0.020%, Mo: 0.015%, As: 0.005%, and the balance is Fe and unavoidable impurities.

[0052] 1.2. After the continuous casting billet has been heated and dephosphorized, hot rolling is performed to obtain an initial steel strip, wherein the hot rolling includes a rough rolling process and a finish rolling process, the start rolling temperature of the rough rolling process is 1150°C, the finish rolling temperature is 1095°C, six rough rolling passes are performed during the rough rolling process, and the single pass reduction rates of the rough rolling passes 1 to 6 are 20.08%, 18.98%, 17.97%, 28.73%, 29. 18% and 28.93%; the starting rolling temperature of the finishing rolling treatment is 1045°C, the final rolling temperature is 884°C, 7 finishing rolling passes are performed during the finishing rolling process, and the single-pass reduction rates of 1-7 finishing rolling passes are 46.80%, 40.87%, 34.77%, 32.44%, 29.82%, 20.93% and 13.26% respectively; the convexity C40 of the steel strip is controlled to be 31μm during the hot rolling process.

[0053] 1.3. The initial steel strip is cooled to a coiling temperature and then coiled to obtain a tinplate wide steel strip; wherein the thickness of the tinplate wide steel strip is 2.75 mm, the cooling rate is 15°C / s, and the coiling temperature is 576°C.

[0054] Example 2

[0055] 2.1. A continuous casting billet with a width of 1477 mm and a thickness of 230 mm was subjected to a heat treatment, wherein the furnace temperature of the heat treatment was 1206°C, the furnace time was 200 min, and the soaking time was 22 min; wherein the components of the continuous casting billet, by weight percentage, included: C: 0.075%, Si: 0.010%, Mn: 0.32%, P: 0.012%, S: 0.009%; Als: 0.020%, N: 0.0023%, Cu: 0.020%, Ni: 0.015%, Cr: 0.015%, Mo: 0.020%, As: 0.007%, and the balance was Fe and unavoidable impurities.

[0056] 2.2. After the continuous casting billet has been heated and dephosphorized, hot rolling is performed to obtain an initial steel strip, wherein the hot rolling includes a rough rolling process and a finish rolling process, the start rolling temperature of the rough rolling process is 1140°C, the finish rolling temperature is 1086°C, six rough rolling passes are performed during the rough rolling process, and the single pass reduction rates of the rough rolling passes 1 to 6 are 20.08%, 18.96%, 17.95%, 28.70%, 29. 39% and 28.93%; the starting rolling temperature of the finishing rolling treatment is 1015°C, the final rolling temperature is 877°C, 7 finishing rolling passes are performed during the finishing rolling process, and the single-pass reduction rates of 1-7 finishing rolling passes are 46.25%, 42.71%, 36.52%, 32.07%, 28.05%, 20.08% and 13.68% respectively; the convexity C40 of the steel strip is controlled to be 28μm during the hot rolling process.

[0057] 2.3. The initial steel strip is cooled to the coiling temperature and then coiled to obtain a tinplate wide steel strip; wherein the thickness of the tinplate wide steel strip is 2.75 mm, the cooling rate is 20°C / s, and the coiling temperature is 568°C.

[0058] Example 3

[0059] 3.1. A continuous casting billet with a width of 1378 mm and a thickness of 230 mm was subjected to a heat treatment, wherein the furnace temperature of the heat treatment was 1215° C., the furnace time was 170 min, and the soaking time was 30 min; wherein the components of the continuous casting billet, by weight percentage, included: C: 0.060%, Si: 0.013%, Mn: 0.38%, P: 0.010%, S: 0.006%; Als: 0.030%, N: 0.0025%, Cu: 0.015%, Ni: 0.018%, Cr: 0.020%, Mo: 0.010%, As: 0.005%, and the balance was Fe and unavoidable impurities.

[0060] 3.2. After dephosphorization, the continuous casting billet after heating treatment is subjected to hot rolling treatment to obtain an initial steel strip, wherein the hot rolling treatment includes rough rolling treatment and finish rolling treatment, the starting rolling temperature of the rough rolling treatment is 1135°C, the final rolling temperature is 1081°C, and 6 rough rolling passes are performed during the rough rolling process, and the single pass reduction rates of the 1st to 6th rough rolling passes are 20.07%, 18.96%, 17.97%, 28.77%, 29. 05% and 28.72%; the starting rolling temperature of the finishing rolling treatment is 1003°C, the final rolling temperature is 873°C, 7 finishing rolling passes are carried out during the finishing rolling process, and the single-pass reduction rates of 1-7 finishing rolling passes are 47.55%, 42.95%, 37.91%, 31.39%, 26.49%, 19.19% and 13.12% respectively; the convexity C40 of the steel strip is controlled to be 26μm during the hot rolling process.

[0061] 3.3. The initial steel strip is cooled to the coiling temperature and then coiled to obtain a tinplate wide steel strip; wherein the thickness of the tinplate wide steel strip is 2.75 mm, the cooling rate is 30°C / s, and the coiling temperature is 582°C.

[0062] Experimental example

[0063] The metallographic structure of the tinplate wide steel strip prepared in Example 1 was analyzed. Figure 2 ,from Figure 2 It can be seen that the structure of the tinplate wide steel strip prepared in Example 1 is ferrite + a small amount of pearlite, the grain size is 9.0, and the structure is relatively uniform.

[0064] The mechanical properties of the wide tinplate steel strip prepared in Example 1 were tested, and the results are shown in Table 1. It can be seen from Table 1 that the strength and toughness of the wide tinplate steel strip prepared in Example 1 are not much different at different positions in the width direction, indicating that the mechanical properties of the wide tinplate steel strip in the width direction are relatively uniform.

[0065] It should be noted that in Table 1, 40 mm from the left edge refers to 40 mm from the left edge of the tinplate wide steel strip in the width direction, and 40 mm from the right edge refers to 40 mm from the right edge of the tinplate wide steel strip in the width direction; assuming that the width of the tinplate wide steel strip obtained in Example 1 is L, the 1 / 4 position refers to (1 / 4) L from the left edge of the tinplate wide steel strip in the width direction, the 1 / 2 position refers to (1 / 2) L from the left edge of the tinplate wide steel strip in the width direction, and the 3 / 4 position refers to (3 / 4) L from the left edge of the tinplate wide steel strip in the width direction.

[0066] Table 1

[0067]

[0068]

[0069] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for preparing a wide tinplate steel strip, characterized in that: include: Step S1, after heating the continuous casting billet that meets the tinplate composition requirements, hot rolling is performed to obtain an initial steel strip; wherein the hot rolling treatment includes rough rolling and finishing rolling, and the reduction amount of the continuous casting billet during the rough rolling process accounts for more than 75% of the total reduction amount of the continuous casting billet during the hot rolling process; 6 rough rolling passes and 7 finishing rolling passes are performed during the rough rolling process, wherein the single-pass reduction rate of the first 3 rough rolling passes is more than 17%, the single-pass reduction rate of the last 3 rough rolling passes is more than 27%, and the single-pass reduction rate of the first 4 finishing rolling passes is more than 30%; during the hot rolling process, the convexity C40 of the steel strip is controlled to be 7-47μm; the starting rolling temperature of the rough rolling process is 1100-1200℃, and the final rolling temperature is 1050-1150℃; Step S2, laminar cooling the initial steel strip to a coiling temperature and then coiling it to obtain a wide tinplate steel strip; wherein the width of the wide tinplate steel strip is 1000-1630 mm, the laminar cooling rate is above 10°C / s, and the coiling temperature is 560-600°C.

2. The method for preparing a wide tinplate steel strip according to claim 1, characterized in that: In the step S1, the reduction ratio of each pass of the first three rough rolling passes is 18-20%, the reduction ratio of each pass of the last three rough rolling passes is 28-29%, and the reduction ratio of each pass of the first four finish rolling passes is 34-48%.

3. The method for preparing a wide tinplate steel strip according to claim 2, characterized in that: During the finishing process, the reduction ratio of each of the last three finishing passes is 13-33%, and decreases in sequence from the front to the back. The sum of the reduction ratios of each of the last three finishing passes is more than 45%.

4. The method for preparing a wide tinplate steel strip according to claim 2, characterized in that: During the finishing rolling process, the single pass reduction rate of the 7th finishing rolling is 13-14%.

5. The method for preparing a wide tinplate steel strip according to claim 1, characterized in that: In the step S1, the convexity C40 of the steel strip is controlled to be 26-31 μm during the hot rolling process.

6. The method for preparing a wide tinplate steel strip according to claim 1, characterized in that: In the step S1, the start rolling temperature of the finish rolling process is 1000-1050°C, and the final rolling temperature is 860-900°C.

7. The method for preparing a wide tinplate steel strip according to claim 1, characterized in that: In the step S1, the furnace temperature of the heat treatment is 1170-1240°C, the furnace time is 150-200 minutes, and the soaking time is 22-40 minutes.

8. The method for preparing a wide tinplate steel strip according to claim 1, characterized in that: The thickness of the wide tinplate steel strip is 2.5-5.0 mm.

9. A wide tinplate steel strip, characterized in that: The wide tinplate steel strip is manufactured by the method for preparing the wide tinplate steel strip as described in any one of claims 1 to 8.

10. The wide tinplate steel strip according to claim 9, characterized in that: Measured by weight percentage, the components of the tinplate wide steel strip include: C: 0.052-0.075%, Si: 0-0.025%, Mn: 0.27-0.45%, P: 0-0.015%, S: 0-0.012%; Als: 0.020-0.055%, N: 0-0.0045%, Cu: 0-0.035%, Ni: 0-0.035%, Cr: 0-0.035%, Mo: 0-0.025%, As: 0-0.010%, and the balance is Fe and unavoidable impurities.

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