Hot-rolled plate, preparation method thereof and tin-plated plate

Abstract

The invention relates to a hot-rolled plate, a preparation method thereof and a tin-plated plate, and belongs to the technical field of steel plate preparation. The method comprises the following steps: heating a plate blank in a furnace, and controlling the temperature rise amplitude and the tapping temperature of a soaking section of the heating in the furnace; rough rolling is conducted on the plate blank heated in the furnace, heat preservation is conducted on the plate blank in the rough rolling process, and an intermediate blank is obtained; the intermediate billet is subjected to finish rolling, the reduction rate and the finish rolling temperature of finish rolling are controlled, cooling water between racks is put in the finish rolling process, and the middle and the edges of the intermediate billet have a first temperature difference value; and carrying out laminar cooling on the finish-rolled intermediate billet, and enabling the middle part and the edge part of the finish-rolled intermediate billet to have a second temperature difference value, so as to obtain the hot-rolled plate. According to the embodiment of the invention, the width of the edge mixed crystal area of the hot-rolled substrate is reduced, the prepared hot-rolled plate serves as the substrate, the tin-plated plate is obtained through subsequent tin plating, and the earing (degradation) rate of the tin-plated plate is reduced to a great extent.

Description

Technical Field

[0001] The present application relates to the technical field of steel plate preparation, and in particular to a hot-rolled plate and a preparation method thereof, and a tin-plated plate. Background Art

[0002] Tinplate has good formability, weldability and high hardness. As a cold-rolled low-carbon steel plate, it is widely used in food packaging, container stamping and other fields. With the improvement of production efficiency in downstream processes, the problem of earing in the canning process has become more and more prominent, seriously affecting product quality and yield rate. Research shows that there are many factors affecting this problem, some of which are related to the edge mixed crystal zone of the hot-rolled raw material substrate. Therefore, how to reduce the width of the edge mixed crystal zone of the hot-rolled substrate has become a technical problem that needs to be solved urgently. Summary of the Invention

[0003] The present application provides a hot-rolled plate and a preparation method thereof, and a tin-plated plate, to solve the following technical problem: how to reduce the width of the mixed crystal zone at the edge of the hot-rolled plate.

[0004] In a first aspect, an embodiment of the present application provides a method for preparing a hot-rolled plate, the method comprising:

[0005] Heating the slab in a furnace, and controlling the temperature rise range and tapping temperature of the soaking section of the furnace;

[0006] performing rough rolling on the slab heated in the furnace, and keeping the slab warm during the rough rolling process to obtain an intermediate slab;

[0007] Finish rolling the intermediate billet, controlling the reduction ratio and final rolling temperature of the finish rolling, and adding inter-stand cooling water during the finish rolling process to ensure that a first temperature difference exists between the middle and edge portions of the intermediate billet;

[0008] The intermediate billet after finish rolling is subjected to laminar cooling, and a second temperature difference is made between the middle portion and the edge portion of the intermediate billet after finish rolling to obtain a hot-rolled plate.

[0009] Optionally, the temperature rise range of the soaking section is 20°C to 50°C.

[0010] Optionally, the tapping temperature is 1180°C to 1260°C.

[0011] Optionally, the heating time in the furnace is ≥120 min.

[0012] Optionally, the first temperature difference is ≤60°C; and / or,

[0013] The second temperature difference is ≤40°C.

[0014] Optionally, the final rolling temperature of the finishing rolling is 880°C to 930°C.

[0015] Optionally, the reduction ratio of the finish rolling is >94%.

[0016] Optionally, the final rolling temperature of the rough rolling is 1050°C to 1090°C.

[0017] In a second aspect, an embodiment of the present application provides a hot-rolled plate, which is prepared by the method described in any one of the first aspects.

[0018] In a third aspect, an embodiment of the present application provides a tinplate, which comprises the hot-rolled plate described in any one of the second aspects and a tin-plated layer attached to the hot-rolled plate.

[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0020] The method for preparing the hot-rolled plate provided in the embodiment of the present application comprises: heating the slab in a furnace, and

[0021] Control the temperature rise amplitude and the steel-out temperature of the soaking section heated in the furnace; perform rough rolling on the slab heated in the furnace, and keep the slab warm during the rough rolling process to obtain an intermediate slab; perform finish rolling on the intermediate slab, and control the reduction rate and final rolling temperature of the finish rolling, and add cooling water between the stands during the finish rolling process, so that the middle and the edge of the intermediate slab have a first temperature difference; perform laminar flow cooling on the intermediate slab after finish rolling, and so that the middle and the edge of the intermediate slab after finish rolling have a second temperature difference to obtain a hot-rolled plate. The slab is heated in a furnace, and the temperature rise and tapping temperature in the soaking section of the furnace are controlled, so that the slab has a uniform austenite structure; the slab after furnace heating is rough rolled, and the slab is kept warm during the rough rolling process, which can reduce the temperature drop at the edge of the slab; the intermediate slab is finish rolled, and the reduction rate and final rolling temperature of the finish rolling are controlled, which can reduce the temperature drop in the finish rolling area and obtain a fine and uniform grain structure; the middle and edge of the intermediate slab have a first temperature difference, and the cooling rate of the edge and middle can be adjusted to make the edge structure more uniform, thereby reducing the width of the edge mixed crystal zone; the intermediate slab after finish rolling is laminar cooled, and the middle and edge of the intermediate slab after finish rolling have a second temperature difference, so that the edge structure can be uniformly cooled and transformed, thereby effectively reducing the width of the edge mixed crystal zone of the hot-rolled plate. In summary, the width of the edge mixed crystal zone of the hot-rolled plate is reduced, and the width of the edge mixed crystal zone of the hot-rolled plate can be reduced from more than 80mm to less than 20mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A schematic flow chart of a method for preparing a hot-rolled plate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0027] In this application, unless otherwise specified, the directional words used, such as "upper" and "lower", refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to". In this article, relational 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 actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B can be singular or plural.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] In a first aspect, the present invention provides a method for preparing a hot-rolled plate. Figure 1 A schematic diagram of a process for preparing a hot-rolled plate provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0030] S1. Heating the slab in a furnace and controlling the temperature rise range and tapping temperature of the soaking section of the furnace;

[0031] Control the temperature rise amplitude and tapping temperature in the soaking section. Precise regulation of the temperature rise amplitude in the soaking section can ensure uniform temperature distribution inside the slab, reduce temperature gradients, and avoid structural differences caused by local overheating or overcooling. Reasonable tapping temperature can fully dissolve the alloy elements inside the slab, prevent uneven edge structure caused by element segregation, obtain uniform austenite structure, and provide a basis for obtaining a uniform structural state in the subsequent rolling process.

[0032] In some embodiments, the temperature rise range of the soaking section is 20°C to 50°C.

[0033] The temperature rise amplitude of the soaking section can be 20℃~50℃. The smaller temperature rise in the soaking stage helps to eliminate the temperature gradient generated by the slab during the heating process. There are differences in the heating of the slab at different positions in the heating furnace. By slowly heating the slab by 20℃~50℃, the temperature of each part inside the slab can gradually become consistent. During the austenitization process of the slab with uniform temperature, the phase transformation can proceed synchronously, avoiding the premature or late formation of austenite in some areas due to uneven temperature, thereby ensuring the uniformity of the austenite structure throughout the slab. For example, the temperature rise amplitude of the soaking section can be 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, etc.

[0034] In some embodiments, the tapping temperature is 1180°C to 1260°C.

[0035] The tapping temperature can be between 1180°C and 1260°C. Within this temperature range, alloying elements (such as carbon, manganese, and silicon) in the slab can fully dissolve into the ferrite lattice, forming a uniform austenite solid solution. For example, the tapping temperature can be 1180°C, 1190°C, 1200°C, 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, etc.

[0036] In some embodiments, the heating time in the furnace is ≥120 min.

[0037] The furnace heating time can be ≥ 120 minutes. Sufficient furnace time allows for sufficient diffusion of alloying elements. This furnace heating time allows for sufficient diffusion of alloying elements into the austenite, reducing component segregation. Exemplary furnace heating times can be 120 minutes, 130 minutes, 140 minutes, 150 minutes, 160 minutes, 170 minutes, etc.

[0038] S2, performing rough rolling on the slab heated in the furnace, and keeping the slab warm during the rough rolling process to obtain an intermediate slab;

[0039] Insulating the slab during the rough rolling process effectively reduces heat loss and avoids large temperature differences between the edges and center. A stable temperature field ensures uniform stress distribution during rolling, reduces stress concentration at the edges, promotes uniform grain deformation at the edges and center, and reduces abnormal grain growth at the edges caused by temperature differences, thereby narrowing the width of the mixed crystal zone at the edges. For example, the slab is placed under a heat shield during the rough rolling process.

[0040] In some embodiments, the finishing rolling temperature of the rough rolling is 1050°C to 1090°C.

[0041] The final rolling temperature for rough rolling can be between 1050°C and 1090°C. The austenite in the slab retains good plasticity and low deformation resistance. This temperature range is within the active range for dynamic recrystallization of austenite. During rolling, dynamic recrystallization can promptly eliminate work hardening caused by plastic deformation, continuously renewing and refining the austenite grains. For example, the final rolling temperature for rough rolling can be 1050°C, 1060°C, 1070°C, 1080°C, 1090°C, etc.

[0042] S3, finishing rolling the intermediate billet, controlling the reduction ratio and the final rolling temperature of the finishing rolling, and adding cooling water between stands during the finishing rolling process, so that a first temperature difference exists between the middle and the edge of the intermediate billet;

[0043] Control the finishing reduction rate and final rolling temperature. A suitable reduction rate ensures sufficient grain refinement, and the final rolling temperature is kept within the appropriate phase transformation range, which is conducive to obtaining a uniform and fine structure. Cooling water is added between the stands to create a first temperature difference between the center and edges of the intermediate billet. By adjusting the cooling rates of the center and edges, the edges are prevented from cooling too quickly to form coarse grains or too slowly to cause abnormal grain growth. This balances the uniformity of the structure between the center and edges and suppresses the phenomenon of mixed grains at the edges.

[0044] S4. laminar cooling the intermediate billet after finish rolling, so that the middle and edge portions of the intermediate billet after finish rolling have a second temperature difference, thereby obtaining a hot-rolled plate.

[0045] By controlling the temperature difference between the center and edge of the intermediate billet after finishing, the cooling rate and time can be precisely adjusted according to different steel grades and product requirements. Special cooling strategies are implemented for the edges, such as edge shielding or enhanced cooling, to ensure consistent microstructural transformation between the edges and the center, preventing mixed crystals caused by uneven cooling, and ultimately effectively reducing the width of the mixed crystal zone at the edge of the hot-rolled plate.

[0046] In some embodiments, the first temperature difference is ≤60°C; and / or,

[0047] The second temperature difference is ≤40°C.

[0048] During the finishing rolling process, controlling a smaller temperature difference can ensure that the metal plasticity of the edge and the middle of the intermediate billet is close, avoiding a significant increase in deformation resistance due to excessively low edge temperature, resulting in uneven deformation of the edge and the middle. If the temperature difference is too large, local stress concentration is prone to occur at the edge, resulting in abnormal growth of grains at the edge or microcracks, forming a mixed crystal zone. Controlling the temperature difference within 60°C (adding cooling water between the frames, and the edges having a shielding function) can evenly distribute the rolling force, promote synchronous deformation of the edge and middle tissues, refine the grains, and reduce the risk of mixed crystals. Exemplarily, the first temperature difference can be 60°C, 55°C, 50°C, 45°C, 40°C, 35°C, etc. During the finishing rolling process, cooling water is added between the frames, and the edges of the cooling manifold have a shielding function to reduce the temperature drop at the edges, so as to achieve a first temperature difference between the middle and the edge of the intermediate billet.

[0049] The layer cooling manifold adopts edge shielding to further reduce the temperature drop at the edge and control the temperature difference between the middle and edge of the intermediate billet after finishing rolling (the second temperature difference value ≤ 40°C). The uniform cooling rate enables the edge and the middle to complete the phase change synchronously, prevents the edge from producing coarse structure due to abnormal supercooling, effectively reduces the width of the mixed crystal zone at the edge, and ensures the uniformity of the organization and the quality of the plate shape of the hot-rolled plate. Exemplarily, the second temperature difference value can be 40°C, 35°C, 30°C, 25°C, 20°C, etc. The strip is cooled centrally in the front section of the layer cooling manifold, and the cooling manifold is equipped with an edge shielding function to reduce the temperature drop at the edge and achieve a second temperature difference between the middle and the edge of the intermediate billet after finishing rolling.

[0050] In some embodiments, the final rolling temperature of the finish rolling is 880°C to 930°C.

[0051] The final rolling temperature of the finishing rolling can be 880℃~930℃, which not only ensures that the plasticity and recrystallization of austenite are fully carried out, but also creates good conditions for the subsequent cooling phase transformation. At the same time, cooling water is added between the stands and the edges are provided with a shielding function (temperature difference ≤ 60℃). While controlling the overall temperature, the temperature drop at the edges is reduced to avoid abnormal organization due to excessive cooling at the edges, and maintain the consistency of temperature and organization between the edges and the middle. For example, the final rolling temperature of the finishing rolling can be 880℃, 885℃, 890℃, 895℃, 900℃, 905℃, 910℃, 915℃, 920℃, 925℃, 930℃, etc.

[0052] In some embodiments, the reduction ratio of the finish rolling is >94%.

[0053] The reduction ratio for finishing rolling can be >94%. Through intense plastic deformation, the austenite grains are fully broken and refined, increasing the grain boundary area, providing more nucleation sites for recrystallization, and achieving a uniform and fine grain structure. This reduces the microstructural differences between the edges and the center, thereby reducing the width of the mixed crystal zone at the edges. For example, the reduction ratio for finishing rolling can be 95%, 96%, 97%, etc.

[0054] The method for preparing hot-rolled plates provided in the embodiments of the present application has the following advantages:

[0055] 1. Make the slab structure uniform: Control the temperature rise range and tapping temperature in the soaking zone of the furnace heating to make the slab have a uniform austenite structure;

[0056] 2. Reduce the temperature drop at the edge of the slab: Rough rolling the slab after heating in the furnace and keeping the slab warm during the rough rolling process can reduce the temperature drop at the edge of the slab;

[0057] 3. Obtain fine and uniform grain structure: The intermediate billet is finished rolled, and the reduction rate and final rolling temperature are controlled to reduce the temperature drop in the finishing rolling area, thereby obtaining a fine and uniform grain structure;

[0058] 4. Adjust the cooling rate to make the edge structure uniform: the middle and edge of the intermediate billet have a first temperature difference, and the cooling rate of the edge and the middle can be adjusted to make the edge structure more uniform, thereby reducing the width of the mixed crystal zone at the edge;

[0059] 5. Reduce the width of the mixed crystal zone at the edge of the hot-rolled plate: The intermediate billet after finishing rolling is subjected to laminar cooling, and the middle and edge of the intermediate billet after finishing rolling have a second temperature difference, so that the edge structure can be evenly cooled and transformed, thereby effectively reducing the width of the mixed crystal zone at the edge of the hot-rolled plate.

[0060] In a second aspect, an embodiment of the present application provides a hot-rolled plate, which is prepared by the method described in any one of the first aspects.

[0061] The hot-rolled plate is realized based on the above-mentioned hot-rolled plate preparation method. The specific steps of the hot-rolled plate preparation method can refer to the above-mentioned embodiment. Since the hot-rolled plate adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here.

[0062] In a third aspect, an embodiment of the present application provides a tinplate, which comprises the hot-rolled plate described in any one of the second aspects and a tin-plated layer attached to the hot-rolled plate.

[0063] The mixed crystal width of the edge of the hot-rolled plate is small, and the hot-rolled plate is subsequently tinned to obtain a tin-plated plate, thereby reducing the earing rate of the tin-plated plate.

[0064] The tinplate is realized based on the above-mentioned hot-rolled plate. The specific preparation steps of the hot-rolled plate can refer to the above-mentioned embodiment. Since the tinplate adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0065] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0066] Example 1

[0067] A method for preparing a hot-rolled plate, comprising:

[0068] The slab is heated in a furnace, and the temperature rise amplitude and the tapping temperature in the soaking section of the furnace are controlled; the chemical composition of the slab, calculated by mass fraction, is as follows: C: 0.06%, Si: 0.015%, Mn: 0.35%, S: 0.009%, P: 0.010%, Als: 0.04%, and the rest is iron and residue; the slab thickness is 237 mm, the heating time in the heating furnace is 140 minutes, the temperature rise in the soaking section is 20°C, and the tapping temperature is 1180°C.

[0069] The slab heated in the furnace is subjected to rough rolling, and the slab is kept warm during the rough rolling process to obtain an intermediate slab; the rough rolling adopts a 3+3 mode, a heat preservation cover is put into the rough rolling area, and the rough rolling R2 outlet temperature is 1050℃.

[0070] The intermediate billet is finish rolled, and the reduction ratio and final rolling temperature of the finish rolling are controlled. Cooling water is added between the stands during the finish rolling process, and a first temperature difference is established between the middle and edge portions of the intermediate billet. The intermediate billet thickness at the finish rolling entrance is 40 mm, the finished product thickness is 2.2 mm, the finish rolling reduction ratio is 94.5%, the entrance temperature is 1050° C., and the final rolling temperature is 880° C. Cooling water is added between the F1 and F2 stands, the edge portions are shielded by 30%, and the first temperature difference is 50° C.

[0071] The intermediate billet after finish rolling is subjected to laminar cooling, and the middle and edge parts of the intermediate billet after finish rolling have a second temperature difference to obtain a hot-rolled plate; wherein, the laminar cooling adopts a front-stage centralized cooling process, the cooling manifold is put into edge shielding, the edge shielding amount is 150mm, the second temperature difference is 30°C, and the subsequent coiling temperature of the hot-rolled plate is 580°C.

[0072] Example 2

[0073] A method for preparing a hot-rolled plate, comprising:

[0074] The slab is heated in a furnace, and the temperature rise amplitude and the tapping temperature in the soaking section of the furnace are controlled. The chemical composition of the slab, calculated by mass fraction, is as follows: C: 0.06%, Si: 0.015%, Mn: 0.35%, S: 0.009%, P: 0.010%, Als: 0.04%, and the remainder is iron and residue. The slab thickness is 237 mm, the heating time in the heating furnace is 160 minutes, the temperature rise in the soaking section is 30°C, and the tapping temperature is 1200°C.

[0075] The slab heated in the furnace is subjected to rough rolling, and the slab is kept warm during the rough rolling process to obtain an intermediate slab; the rough rolling adopts a 3+3 mode, a heat preservation cover is put into the rough rolling area, and the rough rolling R2 outlet temperature is 1060℃.

[0076] The intermediate billet is finish rolled, and the finishing reduction rate and the final rolling temperature are controlled. During the finishing rolling process, inter-stand cooling water is added, and a first temperature difference is established between the middle and edge portions of the intermediate billet. The intermediate billet thickness at the finishing rolling entrance is 40 mm, the finished product thickness is 2.0 mm, the finishing reduction rate is 95.0%, the entrance temperature is 1060° C., and the final rolling temperature is 900° C. Cooling water is added between the F1 stands, the edge portion is shielded by 30%, and the first temperature difference is 30° C.

[0077] The intermediate billet after finish rolling is subjected to laminar cooling, and the middle and edge parts of the intermediate billet after finish rolling have a second temperature difference to obtain a hot-rolled plate; wherein, the laminar cooling adopts a front-stage centralized cooling process, the cooling manifold is put into edge shielding, the edge shielding amount is 150mm, the second temperature difference is 10°C, and the subsequent coiling temperature of the hot-rolled plate is 580°C.

[0078] Example 3

[0079] A method for preparing a hot-rolled plate, comprising:

[0080] The slab is heated in a furnace, and the temperature rise amplitude and the tapping temperature in the soaking section of the furnace are controlled. The chemical composition of the slab, calculated by mass fraction, is as follows: C: 0.06%, Si: 0.015%, Mn: 0.35%, S: 0.009%, P: 0.010%, Als: 0.04%, and the rest is iron and residue. The slab thickness is 237 mm, the heating time in the heating furnace is 180 minutes, the temperature rise in the soaking section is 40°C, and the tapping temperature is 1240°C.

[0081] The slab heated in the furnace is subjected to rough rolling, and the slab is kept warm during the rough rolling process to obtain an intermediate slab; the rough rolling adopts a 3+3 mode, a heat preservation cover is put into the rough rolling area, and the rough rolling R2 outlet temperature is 1080℃.

[0082] The intermediate billet is finish rolled, and the finishing reduction rate and the final rolling temperature are controlled. During the finishing rolling process, inter-stand cooling water is added, and a first temperature difference is established between the middle and edge portions of the intermediate billet. The intermediate billet thickness at the finishing rolling entrance is 38 mm, the finished product thickness is 1.8 mm, the finishing reduction rate is 95.3%, the entrance temperature is 1080° C., and the final rolling temperature is 920° C. Cooling water is added between the F1 stands, the edge portion is shielded by 30%, and the first temperature difference is 20° C.

[0083] The intermediate billet after finish rolling is subjected to laminar cooling, and the middle and edge parts of the intermediate billet after finish rolling have a second temperature difference to obtain a hot-rolled plate; wherein, the laminar cooling adopts a front-stage centralized cooling process, the cooling manifold is put into edge shielding, the edge shielding amount is 150mm, the second temperature difference is 5°C, and the subsequent coiling temperature of the hot-rolled plate is 580°C.

[0084] Comparative Example 1

[0085] A method for preparing a hot-rolled plate, comprising:

[0086] The slab is heated in a furnace, and the temperature rise amplitude and the tapping temperature in the soaking section of the furnace are controlled; the chemical composition of the slab, calculated by mass fraction, is as follows: C: 0.06%, Si: 0.015%, Mn: 0.35%, S: 0.009%, P: 0.010%, Als: 0.04%, and the rest is iron and residue; the slab thickness is 237 mm, the heating time in the heating furnace is 110 minutes, the temperature rise in the soaking section is 10°C, and the tapping temperature is 1160°C.

[0087] The slab heated in the furnace is subjected to rough rolling, and the slab is kept warm during the rough rolling process to obtain an intermediate slab; the rough rolling adopts a 3+3 mode, and a heat preservation cover is not put into the rough rolling area. The rough rolling R2 outlet temperature is 1040°C.

[0088] The intermediate billet is finish rolled, and the reduction ratio and final rolling temperature are controlled. The thickness of the intermediate billet at the finishing rolling entrance is 34 mm, the thickness of the finished product is 2.2 mm, the finishing reduction ratio is 93.5%, the entrance temperature is 1050°C, and the final rolling temperature is 860°C. No cooling water is used between the F1 stands.

[0089] The intermediate billet after finish rolling is laminar cooled to obtain hot-rolled plate; wherein, the laminar cooling adopts a front-stage centralized cooling process, the cooling manifold is not shielded at the edge, and the subsequent coiling temperature of the hot-rolled plate is 580°C.

[0090] Comparative Example 2

[0091] A method for preparing a hot-rolled plate, comprising:

[0092] The slab is heated in a furnace, and the temperature rise in the soaking section and the tapping temperature are controlled. The chemical composition of the slab, calculated by mass fraction, is as follows: C: 0.06%, Si: 0.015%, Mn: 0.35%, S: 0.009%, P: 0.010%, Als: 0.04%, and the remainder is iron and residue. The slab thickness is 237 mm, the heating time in the heating furnace is 180 minutes, the temperature rise in the soaking section is 15°C, and the tapping temperature is 1160°C.

[0093] The slab heated in the furnace is subjected to rough rolling, and the slab is kept warm during the rough rolling process to obtain an intermediate slab; the rough rolling adopts a 3+3 mode, and a heat preservation cover is not put into the rough rolling area. The rough rolling R2 outlet temperature is 1070°C.

[0094] The intermediate billet is finish rolled, and the reduction ratio and final rolling temperature are controlled. The thickness of the intermediate billet at the finishing rolling entrance is 34 mm, the thickness of the finished product is 2.2 mm, the finishing reduction ratio is 93.5%, the entrance temperature is 1080°C, and the final rolling temperature is 860°C. No cooling water is used between the F1 stands.

[0095] The intermediate billet after finish rolling is laminar cooled to obtain hot-rolled plate; wherein, the laminar cooling adopts a front-stage centralized cooling process, the cooling manifold is not shielded at the edge, and the subsequent coiling temperature of the hot-rolled plate is 580°C.

[0096] The mixed crystal zone widths at the edges of the hot-rolled plates prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested. The results are shown in Table 1.

[0097] Table 1 Width of mixed crystal zone at the edge of hot-rolled plate

[0098] Serial number Edge mixed crystal zone width mm Example 1 18 Example 2 16 Example 3 15 Comparative Example 1 80 Comparative Example 2 85

[0099] The hot-rolled plates prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were used as substrates and subsequently tinned to obtain tin-plated plates. 500 tons of tinplate was produced and the earing degradation rate at the user end was tested. Please refer to the earing degradation rate shown in Table 2.

[0100] Table 2 Ear-making degradation rate

[0101] Serial number Ear degradation rate (%) Example 1 0.05 Example 2 0.03 Example 3 0.04 Comparative Example 1 8 Comparative Example 2 5

[0102] As can be seen from Tables 1 and 2, the method for preparing a hot-rolled plate provided in the embodiment of the present application reduces the width of the mixed crystal zone at the edge of the hot-rolled substrate. The prepared hot-rolled plate is used as a substrate, and subsequently tinned to obtain a tin-plated plate, which greatly reduces the earing (degradation) rate of the tin-plated plate.

[0103] One or more technical solutions in the embodiments of the present application may have at least the following technical effects or advantages:

[0104] (1) Slab heating system and insulation investment in the rough rolling area to ensure the RDT temperature of the intermediate slab and reduce the temperature drop at the edge;

[0105] (2) The cumulative reduction rate in the finishing rolling area is above 94%, the final rolling temperature is increased to 880-930°C, cooling water is added between the stands, and the edges of the cooling headers are shielded to reduce the temperature drop at the edges of the finishing rolling area;

[0106] (3) The laminar cooling manifold is equipped with an edge shielding function to increase the edge temperature of the laminar cooling area.

[0107] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing a hot-rolled plate, the method comprising: Heating the slab in a furnace, and controlling the temperature rise range and tapping temperature of the soaking section of the furnace; performing rough rolling on the slab heated in the furnace, and keeping the slab warm during the rough rolling process to obtain an intermediate slab; Finish rolling the intermediate billet, controlling the reduction ratio and final rolling temperature of the finish rolling, and adding inter-stand cooling water during the finish rolling process to ensure that a first temperature difference exists between the middle and edge portions of the intermediate billet; The intermediate billet after finish rolling is subjected to laminar cooling, and a second temperature difference is made between the middle portion and the edge portion of the intermediate billet after finish rolling to obtain a hot-rolled plate.

2. The method according to claim 1, characterized in that The temperature rise range of the soaking section is 20°C to 50°C.

3. The method according to claim 1, characterized in that The tapping temperature is 1180°C to 1260°C.

4. The method according to any one of claims 1 to 3, characterized in that The heating time in the furnace is ≥120 min.

5. The method according to claim 1, wherein The first temperature difference is ≤60°C; and / or, The second temperature difference is ≤40°C.

6. The method according to claim 1, characterized in that The final rolling temperature of the finishing rolling is 880°C to 930°C.

7. The method according to claim 1 or 6, characterized in that The reduction ratio of the finish rolling is >94%.

8. The method according to claim 1, characterized in that The final rolling temperature of the rough rolling is 1050°C to 1090°C.

9. A hot-rolled plate, prepared by the method according to any one of claims 1 to 8. 10 . A tinplate comprising the hot-rolled plate according to claim 9 and a tin-plated layer attached to the hot-rolled plate.

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