Tinned plate as well as preparation method and application thereof

Abstract

The invention relates to the technical field of steel rolling and surface treatment, and particularly discloses a tin plate and a preparation method and application thereof. According to the preparation method of the tin-plated plate, one-pass leveling is limited to be carried out by adopting an upper working roll and a lower working roll at the same time, and the difference between the roll diameter of the lower working roll and the roll diameter of the upper working roll is larger than or equal to 0.3 mm; and the tin plating amount of a bright surface during tin electroplating is controlled to be 5.05-5.6 g / m < 2 >, the tin plating amount of a roughened surface is controlled to be 2.45-2.8 g / m < 2 >, and the temperature and speed parameters of soft melting are controlled. By controlling the technological parameters, one face of the prepared tin plate with the differentiated surface is a bright face, the other face of the tin plate is a textured face, the textured rough feeling of the inner wall of a milk powder can body and the smooth and fine feeling of the outer wall can be met at the same time, and the high-end feeling of milk powder products is improved; and the prepared tin-plated plate is good in plate shape, less in tin ash and excellent in hardness.

Description

Technical Field

[0001] This invention relates to the field of steel rolling and surface treatment technology, and in particular to a tin-plated sheet, its preparation method and application. Background Technology

[0002] Tinplate, commonly known as tinplate, is widely used in food packaging, especially for containers with strict shelf-life requirements, such as milk powder cans, due to its excellent sealing, barrier properties, mechanical strength, and formability. Traditional milk powder cans using tinplate typically employ a surface treatment with a uniformly high roughness on both the upper and lower surfaces. This design gives the inner wall of the can a matte metallic finish, providing a pleasing visual appeal to consumers upon opening. However, this uniform surface roughness in milk powder cans has gradually revealed its inherent limitations. Specifically, the outer surface of the can is the direct interface for brand display and consumer tactile experience. A highly rough outer surface makes it difficult to visually present the mirror-like luster and delicate texture characteristic of high-end metal products, and the tactile feel is also slightly rough, lowering the perceived quality of the product.

[0003] Therefore, there is an urgent need in this field for an innovative tin-plated iron that can fundamentally and synergistically optimize the sensory quality of the inner and outer walls of milk powder cans without relying on additional coatings or complex processes, while ensuring the smoothness and stability of the can body processing and forming process, and also guaranteeing the performance of the tin-plated iron. Currently, some researchers have studied the differentiated surface of tin-plated sheets; however, although the resulting tin-plated sheets have differentiated surfaces, their performance is poor and the yield rate is low. Therefore, there is an urgent need to provide a method for preparing tin-plated sheets with differentiated surfaces to improve the performance of tin-plated sheets. Summary of the Invention

[0004] In view of this, the present invention provides a tin-plated sheet, its preparation method, and its application. By controlling the preparation parameters of the tin-plated sheet, the present invention enables the obtained tin-plated sheet to have a differentiated surface, and the obtained tin-plated sheet has good shape, high strength and toughness, and low tin ash content.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: This invention provides a method for preparing a tin-plated plate, comprising the following steps: S1. The continuously cast billet obtained by casting is hot-rolled and cooled to obtain a hot-rolled coil; S2. The hot-rolled coil is pickled, cold-rolled, and then annealed to obtain a cold-rolled sheet. S3. Perform a single leveling process on the cold-rolled sheet to obtain an iron substrate. S4. Perform a tensioning and straightening process on the iron substrate to obtain a tensioned and straightened iron substrate; S5. The straightening iron substrate is electroplated with tin, softened, and passivated to obtain a tin-plated plate. In S3, the first leveling is performed simultaneously by an upper working roller and a lower working roller. The difference between the diameter of the lower working roller and the diameter of the upper working roller is ≥ 0.3 mm. The roughness of the upper working roller is 2.2~2.9 μm, and the roughness of the lower working roller is 0.4~0.9 μm. In step S5, during the tin plating process, the tin plating amount on the bright surface of the straightening iron substrate is 5.05~5.6 g / m. 2 The tin plating amount on the roughened surface of the straightening iron substrate is 2.45~2.8 g / m. 2 ; In S5, the softening temperature is 270~285℃, and the softening speed is 200~300m / min.

[0006] The method for preparing tin-plated sheets provided by this invention limits the roller diameter difference and the roughness of the upper and lower rollers in a single leveling process, resulting in a differentiated surface with one roughened side and the other smooth side. Furthermore, by adjusting the leveling process parameters, the stability of the sheet shape can be ensured through uniform rolling force, avoiding warping and deformation of the tin-plated sheet. During the research process, the inventors discovered that the micro-uneven structure of the differentiated surface can also enhance the mechanical interlocking between the tin plating layer and the substrate, enhance the adhesion between the tin plating layer and the substrate, and thus improve the toughness of the tin-plated sheet. In addition, precise roughness control can also avoid excessively deep scratches or excessive roughening on the substrate surface, reducing the probability of subsequent tin plating layer peeling off, thereby reducing the generation of tin ash.

[0007] This invention further limits the amount of tin plating on the bright and roughened surfaces during electroplating. The differentiated amount of tin plating avoids the problem of stress difference warping caused by excessive thickness of the single-sided plating layer, and maintains a good board shape. At the same time, the differentiated amount of tin plating can increase the thickness of the alloy layer, thereby synergistically improving the strength and toughness of the tin-plated board, while avoiding the problem of peeling caused by plating accumulation or poor adhesion, and reducing the tin ash level.

[0008] The inventors further optimized the reflow parameters. Specific reflow parameters can ensure that the tin-plated plate is heated evenly and avoid deformation of the plate. At the same time, specific reflow parameters can also improve the bonding ability between the tin plating layer and the substrate, thereby ensuring the strength and toughness of the tin-plated plate. In addition, due to the strong bonding ability between the tin plating layer and the substrate, the generation of free tin will be reduced, thereby reducing the tin ash on the surface of the tin-plated plate.

[0009] It should be further noted that in S1, the hot rolling temperature is no longer further limited, and the operation can be carried out using the technical means commonly used in this field.

[0010] It should be further noted that the preparation method of the continuously cast billet in S1 will not be described here, but can be carried out using the technical means commonly used in this field.

[0011] Preferably, in S1, the continuously cast billet comprises the following components in the following mass percentages: C: 0.04%~0.15%, Mn: 0.15%~0.6%, Si≤0.15%, P≤0.04%, S≤0.035%, with the balance being Fe and unavoidable impurities.

[0012] Preferably, in S1, the thickness of the hot-rolled coil is 3~3.5mm.

[0013] For example, in S1, the cooling adopts a composite cooling method that combines atomization cooling and water curtain cooling.

[0014] Preferably, in S1, the cooling rate is 50~80℃ / s.

[0015] By controlling the cooling rate, uniform cooling can be ensured, thereby preventing rib formation defects caused by uneven cooling or improper cooling rate during subsequent cold rolling.

[0016] For example, in S2, the pickling can be performed using conventional techniques known to those skilled in the art.

[0017] Preferably, in S2, during cold rolling, the temperature of the emulsion is 50~60℃.

[0018] Preferably, in S2, the roughness of the work roll used in the cold rolling is 0.65~0.75μm.

[0019] Preferably, in S2, the annealing conditions are: continuous annealing at 665~675℃, annealing speed of 400~500m / min, and total heating and soaking time of 0.66~0.825s.

[0020] Optimal annealing conditions are beneficial for further improving the performance of tinplate.

[0021] More preferably, in S3, the rolling force of the first leveling process is 180 to 350 tons.

[0022] It should be further noted that the upper working roller is an electrical discharge pulse positive texturing roller.

[0023] It should be further noted that the lower working roller is a polished roller for grinding with a grinding wheel mesh size ≥ 80.

[0024] Preferably, in S3, the reduction amount of the first leveling process is 2~4μm.

[0025] Preferably, in S4, the tension straightening process includes the following conditions: unwinding tension of 1000~1500 kg, tension straightening tension of 1200~2000 kg, winding tension of 700~1000 kg, and production speed of 300~400 m / min.

[0026] Preferably, in S5, the tin electroplating is performed using the Florstein stannous sulfate method.

[0027] Preferably, in S5, the conditions for tin electroplating include: the electroplating solution is a phenol sulfonic acid (PSA) plating solution, wherein the tin ion concentration is 25~30g / L and the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3~6g / L.

[0028] For example, the temperature of the electroplating solution is 25~35°C.

[0029] The soft fuse adopts a combination of frequency conversion resistor and induction soft fuse.

[0030] It should be further noted that in S5, passivation adopts a 311-electrochemical dual passivation method, with the charge density controlled at 35~60 C / ft. 2 The weight of a single-sided passivation film is 4.5~6 mg / m³. 2 Alloy layer 0.75~1g / m 2 The amount of oil applied to one side should be controlled at 2~6 mg / m². 2 .

[0031] Preferably, in step S5, the thickness of the tin-plated plate is 0.17~0.33mm.

[0032] The present invention provides a tin-plated sheet, which is prepared by the above-described method for preparing tin-plated sheets.

[0033] This invention provides the application of the above-mentioned tin-plated sheet in the preparation of milk powder cans.

[0034] Compared with the prior art, the present invention has the following beneficial effects: (1) By limiting the specific parameters of the upper and lower working rollers during the flattening process, the present invention has prepared tin-plated plates with different roughnesses. The tin-plated plates prepared have similar elongation on the upper and lower surfaces, good plate shape, and excellent strength. (2) The present invention further optimizes the reflow parameters, enhances the bonding force between the tin layer and the substrate, and significantly reduces the tin ash on the surface of the tin-plated plate; (3) By adjusting the passivation process, the present invention can also ensure good wettability and paint film adhesion during subsequent coating and printing processes. Attached Figure Description

[0035] Figure 1 A micrograph of the bright surface of the tin-plated plate obtained in Example 1 of the present invention; Figure 2 This is a micrograph of the roughened surface of the tin-plated plate obtained in Example 1 of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] Example 1 This embodiment provides a method for preparing a tin-plated plate, including the following steps: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method that combines atomization cooling and water curtain cooling, and the cooling rate is controlled at 50℃ / s to obtain a hot-rolled coil with a thickness of 3mm. The continuously cast billet comprises the following components by mass percentage: C: 0.1%, Mn: 0.4%, Si: 0.1%, P: 0.04%, S: 0.035%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 50℃, and the roughness of the work rolls used for cold rolling is 0.65μm. Then it is annealed at 665℃ with an annealing speed of 400m / min. The total time for annealing heating and homogenization is 0.825s, resulting in a cold-rolled sheet with a thickness of 0.172mm. S3. The cold-rolled sheet undergoes a single leveling process with a rolling force of 350 tons. The upper and lower work rolls are used simultaneously. The difference between the diameter of the lower work roll and the diameter of the upper work roll is 0.3 mm. The lower work roll is a grinding roller with a roughness of 0.4~0.6μm and a grinding wheel mesh count ≥80. The upper work roll is an electrical discharge pulse positive texturing roller with a roughness of 2.4~2.6μm. The reduction in one leveling process is 2μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1500 kg, a tension straightening tension of 1600 kg, a winding tension of 800 kg, and a production speed of 300 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 35℃, the tin ion concentration is 25 g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3 g / L, and the tin plating amount on the bright surface is 5.05 g / m. 2 The tin plating amount on the roughened surface is 2.8 g / m 2The remelting process was carried out at 270℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 200 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 50 C / ft. 2 Single-sided passivation film weight 5mg / m 2 Alloy layer 1g / m 2 The amount of oil applied to one side should be controlled at 2 mg / m². 2 A tin-plated sheet with a thickness of 0.17 mm was obtained.

[0038] Example 2 This embodiment provides a method for preparing a tin-plated plate, including the following steps: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method combining atomization cooling and water curtain cooling, and the cooling rate is controlled at 80℃ / s to obtain a hot-rolled coil with a thickness of 3.5mm. The continuously cast billet comprises the following components by mass percentage: C: 0.15%, Mn: 0.5%, Si: 0.13%, P: 0.02%, S: 0.01%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 60℃, and the roughness of the work rolls used for cold rolling is 0.75μm. Then it is annealed at 675℃ with an annealing speed of 450m / min. The total time for annealing heating and homogenization is 0.733s, resulting in a cold-rolled sheet with a thickness of 0.304mm. S3. The cold-rolled sheet undergoes a single leveling process with a rolling force of 200 tons. The upper and lower work rolls are used simultaneously. The difference between the diameter of the lower work roll and the diameter of the upper work roll is 0.5 mm. The lower work roll is a grinding roller with a roughness of 0.7~0.8μm and a grinding wheel mesh count ≥80. The upper work roll is an electrical discharge pulse positive texturing roller with a roughness of 2.8~2.9μm. The reduction in one leveling process is 4μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1200 kg, a tension straightening tension of 2000 kg, a winding tension of 900 kg, and a production speed of 350 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 30℃, the tin ion concentration is 30 g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 6 g / L, and the tin plating amount on the bright surface is 5.3 g / m. 2 The tin plating amount on the roughened surface is 2.5 g / m 2The remelting process was carried out at 280℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 250 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 60 C / ft. 2 The weight of the single-sided passivation film is 6 mg / m². 2 Alloy layer 0.8g / m 2 The amount of oil applied to one side should be controlled at 3 mg / m². 2 This yields a tin-plated sheet with a thickness of 0.3 mm.

[0039] Example 3 This embodiment provides a method for preparing a tin-plated plate, including the following steps: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method combining atomization cooling and water curtain cooling, and the cooling rate is controlled at 80℃ / s to obtain a hot-rolled coil with a thickness of 3.5mm. The continuously cast billet comprises the following components by mass percentage: C: 0.05%, Mn: 0.15%, Si: 0.05%, P: 0.01%, S: 0.015%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 65℃, and the roughness of the work rolls used for cold rolling is 0.7μm. Then it is annealed at 680℃ with an annealing speed of 500m / min. The total time for annealing heating and homogenization is 0.66s, resulting in a cold-rolled sheet with a thickness of 0.333mm. S3. The cold-rolled sheet undergoes a single leveling process with a rolling force of 260 tons. The upper and lower work rolls are used simultaneously. The difference between the diameter of the lower work roll and the diameter of the upper work roll is 0.8 mm. The lower work roll is a grinding roller with a roughness of 0.8~0.9 μm and a grinding wheel mesh count ≥80. The upper work roll is an electrical discharge pulse positive texturing roller with a roughness of 2.5~2.7 μm. The reduction in one leveling process is 3 μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1000 kg, a tension straightening tension of 1400 kg, a winding tension of 700 kg, and a production speed of 400 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 25℃, the tin ion concentration is 26 g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 4 g / L, and the tin plating amount on the bright surface is 5.6 g / m. 2 The tin plating amount on the roughened surface is 2.7 g / m 2The remelting process was carried out at 285℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 300 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 35 C / ft. 2 The weight of the single-sided passivation film is 4.5 mg / m². 2 Alloy layer 0.9g / m 2 The amount of oil applied to one side should be controlled at 4 mg / m². 2 A tin-plated sheet with a thickness of 0.33 mm was obtained.

[0040] Comparative Example 1 This comparative example provides a method for preparing a tin-plated plate, which differs from Example 1 in that the diameter of the lower working roll is the same as that of the upper working roll. Specifically, the steps include the following: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method that combines atomization cooling and water curtain cooling, and the cooling rate is controlled at 50℃ / s to obtain a hot-rolled coil with a thickness of 3mm. The continuously cast billet comprises the following components by mass percentage: C: 0.1%, Mn: 0.4%, Si: 0.1%, P: 0.04%, S: 0.035%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 50℃, and the roughness of the work rolls used for cold rolling is 0.65μm. Then it is annealed at 665℃ with an annealing speed of 400m / min. The total time for annealing heating and homogenization is 0.825s, resulting in a cold-rolled sheet with a thickness of 0.172mm. S3. The cold-rolled sheet is subjected to a single leveling process with a rolling force of 350 tons. The upper and lower work rolls are used simultaneously. The lower work roll is a grinding roller with a roughness of 0.4~0.6μm and a grinding wheel mesh number of ≥80. The upper work roll is an electric spark pulse positive texturing roller with a roughness of 2.4~2.6μm. The reduction of the single leveling process is 2μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1500 kg, a tension straightening tension of 1600 kg, a winding tension of 800 kg, and a production speed of 300 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 35℃, the tin ion concentration is 25 g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3 g / L, and the tin plating amount on the bright surface is 5.05 g / m. 2 The tin plating amount on the roughened surface is 2.8 g / m 2The remelting process was carried out at 270℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 200 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 50 C / ft. 2 Single-sided passivation film weight 5mg / m 2 Alloy layer 1g / m 2 The amount of oil applied to one side should be controlled at 2 mg / m². 2 A tin-plated sheet with a thickness of 0.17 mm was obtained.

[0041] Comparative Example 2 This comparative example provides a method for preparing a tin-plated plate, which differs from Example 1 in that the tin plating amount on the bright surface of the straightening iron substrate is 4 g / m. 2 ; Specifically, the steps include the following: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method that combines atomization cooling and water curtain cooling, and the cooling rate is controlled at 50℃ / s to obtain a hot-rolled coil with a thickness of 3mm. The continuously cast billet comprises the following components by mass percentage: C: 0.1%, Mn: 0.4%, Si: 0.1%, P: 0.04%, S: 0.035%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 50℃, and the roughness of the work rolls used for cold rolling is 0.65μm. Then it is annealed at 665℃ with an annealing speed of 400m / min. The total time for annealing heating and homogenization is 0.825s, resulting in a cold-rolled sheet with a thickness of 0.172mm. S3. The cold-rolled sheet undergoes a single leveling process with a rolling force of 350 tons. The upper and lower work rolls are used simultaneously. The difference between the diameter of the lower work roll and the diameter of the upper work roll is 0.3 mm. The lower work roll is a grinding roller with a roughness of 0.4~0.6μm and a grinding wheel mesh count ≥80. The upper work roll is an electrical discharge pulse positive texturing roller with a roughness of 2.4~2.6μm. The reduction in one leveling process is 2μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1500 kg, a tension straightening tension of 1600 kg, a winding tension of 800 kg, and a production speed of 300 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 35℃, the tin ion concentration is 25g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3g / L, and the tin plating amount on the bright surface is 4g / m². 2 The tin plating amount on the roughened surface is 2.8 g / m 2The remelting process was carried out at 270℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 200 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 50 C / ft. 2 Single-sided passivation film weight 5mg / m 2 Alloy layer 1g / m 2 The amount of oil applied to one side should be controlled at 2 mg / m². 2 A tin-plated sheet with a thickness of 0.17 mm was obtained.

[0042] Comparative Example 3 This comparative example provides a method for preparing a tin-plated plate, which differs from Example 1 in that: the softening rate is increased; Specifically, the steps include the following: S1. The continuously cast billet obtained by casting is hot rolled using a cooling method that combines atomization cooling and water curtain cooling, and the cooling rate is controlled at 50℃ / s to obtain a hot-rolled coil with a thickness of 3mm. The continuously cast billet comprises the following components by mass percentage: C: 0.1%, Mn: 0.4%, Si: 0.1%, P: 0.04%, S: 0.035%, with the balance being Fe and unavoidable impurities; S2. The hot-rolled coil is pickled and then cold-rolled. The temperature of the emulsion during cold rolling is 50℃, and the roughness of the work rolls used for cold rolling is 0.65μm. Then it is annealed at 665℃ with an annealing speed of 400m / min. The total time for annealing heating and homogenization is 0.825s, resulting in a cold-rolled sheet with a thickness of 0.172mm. S3. The cold-rolled sheet undergoes a single leveling process with a rolling force of 350 tons. The upper and lower work rolls are used simultaneously. The difference between the diameter of the lower work roll and the diameter of the upper work roll is 0.3 mm. The lower work roll is a grinding roller with a roughness of 0.4~0.6μm and a grinding wheel mesh count ≥80. The upper work roll is an electrical discharge pulse positive texturing roller with a roughness of 2.4~2.6μm. The reduction in one leveling process is 2μm, resulting in an iron substrate. S4. The iron substrate is subjected to tension straightening treatment with an unwinding tension of 1500 kg, a tension straightening tension of 1600 kg, a winding tension of 800 kg, and a production speed of 300 m / min to obtain the tension straightened iron substrate. S5. The straightened iron substrate is electroplated with tin using the Florstein stannous sulfate method. The electroplating solution is phenol sulfonic acid (PSA) solution, the temperature is 35℃, the tin ion concentration is 25 g / L, the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3 g / L, and the tin plating amount on the bright surface is 5.05 g / m. 2 The tin plating amount on the roughened surface is 2.8 g / m 2The remelting process was carried out at 270℃ using a combination of variable frequency resistance and induction remelting at a remelting speed of 350 m / min. Passivation was performed using a 311-electrochemical dual passivation method with a charge density controlled at 50 C / ft. 2 Single-sided passivation film weight 5mg / m 2 Alloy layer 0.65g / m 2 The amount of oil applied to one side should be controlled at 2 mg / m². 2 A tin-plated sheet with a thickness of 0.17 mm was obtained.

[0043] Example of effect The surface roughness, hardness, tensile strength, elongation, tin ash and plate shape of the tin-plated plates prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The surface roughness testing method is in accordance with the national standard GB / T 2523-2022, the hardness testing method is in accordance with the national standard GB / T 230.1-2018, the tensile test is in accordance with the national standard GB / T 228.1-2021, and the tin ash and plate shape testing methods are in accordance with the national standard GB / T 2520-2017. The tin-plated sheet provided by this invention must meet the following requirements: tin ash grade ≤ 1, plate shape requirements: edge waviness height ≤ 1mm, L-warp ≤ 25mm, C-warp ≤ 10mm; yield strength: 415±30MPa, tensile strength: 420±30MPa, elongation: 30%~40%, hardness: 62±3HR30T.

[0044] The specific test results are shown in Tables 1-3: Table 1

[0045] Table 2

[0046] Table 3

[0047] By this application Figure 1 and Figure 2 It can be seen that, Figure 1 This is a micrograph of the bright surface of a tin-plated sheet. Figure 2 The image shows a micrograph of the roughened surface of a tinplate. As can be seen from the image, the glossy surface of the tinplate is uniform and smooth with evenly distributed peaks and troughs; while the roughened surface has obvious roughening patterns that completely cover the entire surface.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a tin-plated sheet, characterized in that, Includes the following steps: S1. The continuously cast billet obtained by casting is hot-rolled and cooled to obtain a hot-rolled coil; S2. The hot-rolled coil is pickled, cold-rolled, and then annealed to obtain a cold-rolled sheet. S3. Perform a single leveling process on the cold-rolled sheet to obtain an iron substrate. S4. Perform a tensioning and straightening process on the iron substrate to obtain a tensioned and straightened iron substrate; S5. The straightening iron substrate is electroplated with tin, softened, and passivated to obtain a tin-plated plate. In S3, the first leveling is performed simultaneously by an upper working roller and a lower working roller. The difference between the diameter of the lower working roller and the diameter of the upper working roller is ≥ 0.3 mm. The roughness of the upper working roller is 2.2~2.9 μm, and the roughness of the lower working roller is 0.4~0.9 μm. In step S5, during the tin plating process, the tin plating amount on the bright surface of the straightening iron substrate is 5.05~5.6 g / m. 2 The tin plating amount on the roughened surface of the straightening iron substrate is 2.45~2.8 g / m. 2 ; In S5, the softening temperature is 270~285℃, and the softening speed is 200~300m / min.

2. The method for preparing tin-plated steel sheet as described in claim 1, characterized in that, In S1, the continuously cast billet comprises the following components in the following mass percentages: C: 0.04%~0.15%, Mn: 0.15%~0.6%, Si≤0.15%, P≤0.04%, S≤0.035%, with the balance being Fe and unavoidable impurities.

3. The method for preparing tin-plated steel sheet as described in claim 1, characterized in that, In S1, the thickness of the hot-rolled coil is 3~3.5mm; In S1, the cooling rate is 50~80℃ / s.

4. The method for preparing a tin-plated plate as described in claim 1, characterized in that, In S2, the annealing conditions are: continuous annealing at 660~680℃, annealing speed of 400~500m / min, and total heating and soaking time of 0.66~0.825s.

5. The method for preparing a tin-plated plate as described in claim 1, characterized in that, In S2, the rolling force of the first leveling process is 180~350 tons.

6. The method for preparing a tin-plated plate as described in claim 1, characterized in that, In S3, the reduction amount of the first leveling process is 2~4μm; In S4, the tension straightening process includes the following conditions: unwinding tension of 1000~1500kg, tension straightening tension of 1200~2000kg, winding tension of 700~1000kg, and production speed of 300~400m / min.

7. The method for preparing a tin-plated plate as described in claim 1, characterized in that, In S5, the conditions for tin electroplating include: the electroplating solution is a phenol sulfonic acid (PSA) plating solution, wherein the tin ion concentration is 25~30g / L and the concentration of α-naphthol sulfonic acid polyoxyethylene ether is 3~6g / L.

8. The method for preparing a tin-plated plate as described in claim 1, characterized in that, In S5, the thickness of the tin-plated plate is 0.17~0.33mm.

9. A tin-plated sheet, characterized in that, It is prepared by the method of any one of claims 1 to 8.

10. The application of the tin-plated sheet according to claim 9 in the preparation of milk powder cans.

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