Orientation Control Method of Surface Grain Growth on Low-Tin Tin Plate

Abstract

The invention discloses a method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate, comprising the following steps: 1. electrolytically degreasing a cold-rolled steel strip substrate; 2. pickling the cold-rolled steel strip substrate with a pickling solution to remove the oxide film on the surface of the cold-rolled steel strip substrate; 3. electroplating the cold-rolled steel strip substrate after pickling with a tin-plating solution; the tin-plating solution is a methyl sulfonate plating solution, and a grain orientation control agent is added to the tin-plating solution, and the grain orientation control agent is a mixture of a hydroxybenzenesulfonic acid solution and a salicylic acid solution; 4. fluxing the cold-rolled steel strip substrate after tin-plating with a flux, and washing and drying after fluxing to form a low-tin tin-plated plate; 5. soft melting the low-tin tin-plated plate to form an alloy layer, and passivation and oiling processes are performed. The invention can control the tin-plating amount of the tin-plated plate and the grain growth orientation of the alloy layer, and improve the quality of the alloy layer and the corrosion resistance of the low-tin tin-plated plate.

Description

Technical Field

[0001] The invention relates to a production control method for a tinplate, in particular to an orientation control method for surface grain growth of a low-tin tinplate. Background Art

[0002] Tinplate is a product that is cold-rolled low-carbon thin steel plate coated with pure tin on both sides. It is a product with complex production technology, strong technicality, long manufacturing process, high quality requirements and great manufacturing difficulty. Tin provides excellent surface properties such as glossiness, and has the characteristics of being non-toxic, corrosion-resistant, and not easy to crack. It can be used as a packaging material for food and beverages. However, the price of tin is 20-30 times that of iron, and the material is soft and has low strength. When producing tinplate, the tin layer should be as thin as possible while ensuring that the product has excellent surface properties (i.e. good corrosion resistance, bright appearance, and good printing performance).

[0003] Traditional electroplating tinning liquid uses sulfuric acid, fluoroboric acid, halogen reagents, phenolsulfonic acid (PSA) and other systems. In recent years, with the gradual improvement of environmental protection requirements, electroplating tinning liquid has gradually developed from phenolsulfonic acid (PSA) plating liquid system to environmentally friendly methanesulfonate (MSA) system. At the same time, with the increasing requirements of tin-plated steel plate users for low cost, products are gradually developing towards low tin plating, and there are more and more thin tin-plated plate products with 1.1g / m2 or even lower tin plating. However, in actual production, tin-plated plates with low tin content have the problem of substandard corrosion resistance. The main reason is: the orientation of the grain growth of the tin-iron alloy layer on the surface of the tin-plated plate, that is, the grain orientation. Tin-plated plates with dense grain growth on the surface of the tin-iron alloy layer have relatively good corrosion resistance, and the main factor affecting the density of the tin-iron alloy layer is the growth direction of the alloy layer grains.

[0004] Chinese invention patent application CN202010750406.7 discloses a composite-coated tinplate production process and tinplate, which includes: degreasing and pickling the steel substrate; electroplating tin on the steel substrate, with a single-sided tin plating amount of 0.15-1.0g / m2, and then rinsing to form a pure tin layer with a thickness of 0.15-1um on the surface of the steel substrate; melting the tinned layer to make it leveled to produce a bright surface, and forming a tin-iron alloy layer with a thickness of 0.08-0.12um between the steel substrate and the pure tin layer; electroplating chromium on the surface of the tinned steel substrate and rinsing to form a chromium metal layer and a chromium hydrate oxide layer on the surface of the pure tin layer; and finally applying oil to the surface to form an oil film layer. This production process relies on the passivation process to improve the corrosion resistance of the tinplate, that is, increasing the passivation layer thickness by increasing the concentration of the passivation solution, but this production process will increase the emission of hexavalent chromium and cause environmental pollution. Summary of the invention

[0005] The purpose of the present invention is to provide a method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate, which can control the tin plating amount of the tin-plated plate and the grain growth orientation of the alloy layer, and improve the quality of the alloy layer and the corrosion resistance of the low-tin tin-plated plate.

[0006] The present invention is achieved in that:

[0007] A method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate, comprising the following steps:

[0008] Step 1: Electrolytically degreasing the cold-rolled steel strip substrate;

[0009] Step 2: pickling the cold-rolled steel strip substrate with a pickling solution to remove the oxide film on the surface of the cold-rolled steel strip substrate;

[0010] Step 3: electroplating tin on the pickled cold-rolled steel strip substrate with an electroplating tin solution;

[0011] The electro-tin plating solution is a methyl sulfonate plating solution, and a grain orientation control agent is added to the electro-tin plating solution;

[0012] Step 4: Use flux to flux the cold-rolled steel strip substrate after electroplating tin, and then clean and dry it to make a low-tin tin-plated plate;

[0013] Step 5: Soft-melt the low-tin tin-plated plate to form an alloy layer, and then perform passivation and oiling processes.

[0014] In the step 1, the cold-rolled steel strip substrate is electrolytically degreased by a cathode electrolytic degreasing method;

[0015] The electrolyte of the cathode electrolytic degreasing method includes NaOH solution, anionic surfactant and defoaming agent;

[0016] The temperature of the cathode electrolytic degreasing method is 45-60°C, the time is 2-5s, and the electrolytic current density is 10-15A / dm 2 .

[0017] The concentration of the NaOH solution is 40-80 g / L; the concentration of the anionic surfactant is 2-7 g / L, and the anionic surfactant can be one of carboxylic acid sodium salt, sulfonic acid sodium salt, and sulfate sodium salt; the concentration of the defoamer is 1-3 g / L, and the defoamer is polyether modified silicone oil.

[0018] In step 2, the pickling solution is a mixture of a nitric acid solution and a phosphoric acid solution, wherein the concentration of the nitric acid solution is 2-7 g / L, and the concentration of the phosphoric acid solution is 20-40 g / L.

[0019] In the step 2, the pickling time is 2-5s.

[0020] In the step 3, the grain orientation control agent is prepared by mixing a hydroxybenzenesulfonic acid solution and a salicylic acid solution, wherein the concentration of the hydroxybenzenesulfonic acid solution is 1-10 ml / L, and the concentration of the salicylic acid solution is 2-7 ml / L.

[0021] In the step 3, the Sn in the electroplating tin solution 2+ The concentration is 20-25g / L; the current of electrotin is 8-12A / dm2, and the temperature of the electrotin solution is 55-65℃.

[0022] In the step 4, the flux is prepared by mixing phenolsulfonic acid solution, sulfosalicylic acid solution and alkyl glucoside solution.

[0023] The concentration of the phenolsulfonic acid solution is 10-50 ml / L, the concentration of the sulfosalicylic acid solution is 5-15 ml / L, and the concentration of the alkyl glucoside solution is 1-5 ml / L.

[0024] The temperature of the fluxing is room temperature.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention adds a grain orientation control agent formed by mixing a hydroxybenzenesulfonic acid solution and a salicylic acid solution to the electrotin solution, which can effectively control the grain growth orientation of the alloy layer. The alloy layer has good grain growth, dense grain arrangement, high consistency of grain orientation, and excellent overall quality of the alloy layer, so that the corrosion resistance of the low-tin tin-plated plate can meet the use standard.

[0027] 2. The present invention can enhance the process stability of low-tin tin-plated sheets in the production process by fluxing, cleaning and drying the tin-plated sheets. 2 The tin layer on the surface of the tinplate can still be kept uniform, thereby improving the surface quality and corrosion resistance of the tinplate, and reducing the production cost of the tinplate, which meets market demand.

[0028] 3. The present invention is applicable to the tin-plating process using a methanesulfonate plating solution system, has high versatility, and the production process complies with environmental protection standards.

[0029] The present invention can effectively control the amount of tin on the surface of the tin-plated plate by adjusting the parameters of the tin-plating production process, and at the same time control the grain growth orientation of the alloy layer, thereby improving the quality of the alloy layer and making the corrosion resistance of the low-tin-content tin-plated plate meet the standard, thereby solving the problem of the corrosion resistance of the low-tin-content tin-plated plate not meeting the standard in the actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1It is a general XRD test spectrum of a low-tin tin-plated plate produced by the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention; wherein the solid line is the XRD test curve of Example 1, and the dotted line is the XRD test curve of Example 2;

[0031] Figure 2 It is a partial XRD test spectrum of a low-tin tin-plated plate produced by the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention; wherein the solid line is the XRD test curve of Example 1, and the dotted line is the XRD test curve of Example 2;

[0032] Figure 3 This is a metallographic image of a low-tin tin-plated plate produced in Example 1 of the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention;

[0033] Figure 4 This is a SEM test image of a low-tin tin-plated plate produced in Example 1 of the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention;

[0034] Figure 5 This is a metallographic image of a low-tin tin-plated plate produced by Example 2 of the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention;

[0035] Figure 6 This is a SEM test picture of a low-tin tin-plated plate produced by Example 2 of the method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] A method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate, comprising the following steps:

[0038] Step 1: Electrolytically degreasing the cold-rolled steel strip substrate can remove residual oil stains on the surface of the cold-rolled steel strip substrate.

[0039] Preferably, the cathode electrolytic degreasing method can be used to electrolytically degrease the cold-rolled steel strip substrate. The specific operation is as follows: the temperature of the cathode electrolytic degreasing method is 45-60°C, the time is 2-5s, and the electrolytic current density is 10-15A / dm 2 .

[0040] The electrolyte of the cathode electrolytic degreasing method comprises NaOH solution, anionic surfactant and defoaming agent.

[0041] The concentration of the NaOH solution is 40-80 g / L.

[0042] The concentration of the anionic surfactant is 2-7 g / L, and the anionic surfactant can be one of carboxylic acid sodium salt, sulfonic acid sodium salt and sulfate sodium salt.

[0043] The concentration of the defoamer is 1-3 g / L, and the defoamer can be polyether-modified silicone oil.

[0044] Step 2: Pickle the cold-rolled steel strip substrate with a pickling solution to remove the oxide film on the surface of the cold-rolled steel strip substrate so that the cold-rolled steel strip substrate can better combine with the tin layer during the tinning process, thereby ensuring the quality of tinning.

[0045] The pickling solution is a mixture of a nitric acid solution and a phosphoric acid solution, wherein the concentration of the nitric acid solution is 2-7 g / L, and the concentration of the phosphoric acid solution is 20-40 g / L.

[0046] The pickling time is 2-5s.

[0047] Step 3: Electroplating tin on the pickled cold-rolled steel strip substrate with an electroplating tin solution.

[0048] The electro-tinning solution can adopt a methylsulfonate plating solution, and a grain orientation control agent is added to the electro-tinning solution. The grain orientation control agent is a mixture of a hydroxybenzenesulfonic acid solution and a salicylic acid solution, which can effectively control the grain growth orientation of the alloy layer. The alloy layer has good grain growth, dense grain arrangement, high grain orientation consistency, and excellent overall quality of the alloy layer, so that the corrosion resistance of the low-tin tin-plated plate can meet the use standard. The methylsulfonate plating solution can adopt an existing MSA system plating solution, such as the plating solution used in Chinese invention patent application CN202011060982.5.

[0049] The concentration of the hydroxybenzenesulfonic acid solution is 1-10 ml / L, and the concentration of the salicylic acid solution is 2-7 ml / L.

[0050] The tin ions Sn in the electroplating tin solution 2+ The concentration is 20-25g / L.

[0051] The current of the electroplating tin is 8-12A / dm 2 , the temperature of the electrotin plating solution is 55-65°C. The control of low tin plating amount is achieved by controlling the tin ion concentration in the electrotin plating solution, the electroplating current density, the electroplating time and the electroplating time.

[0052] Step 4: Use flux to flux the cold-rolled strip steel substrate after electrotinning, clean and dry it after fluxing to make a low-tin tin-plated plate. Fluxing can promote the fluidity of tin on the surface of the strip, improve flatness, refine grains, inhibit the formation of oxides on the surface of the tin-plated plate, and provide nucleation sites for tin.

[0053] The flux is a mixture of phenolsulfonic acid solution, sulfosalicylic acid solution and alkyl glucoside solution. Phenolsulfonic acid mainly exhibits antioxidant properties and controls the generation of tin oxides; sulfosalicylic acid increases the flowability of tin during the reflow process, and alkyl glucoside is mainly used to control the growth orientation of the tin-iron alloy layer.

[0054] The concentration of the phenolsulfonic acid solution is 10-50 ml / L, the concentration of the sulfosalicylic acid solution is 5-15 ml / L, and the concentration of the alkyl glucoside solution is 1-5 ml / L.

[0055] The temperature of the fluxing is room temperature, generally 20-30°C.

[0056] Step 5: Soft-melt the low-tin tin-plated sheet to form an alloy layer, and perform post-processing processes such as passivation and oiling. Post-processing processes such as soft-melt, passivation and oiling are conventional production processes for tin-plated sheets and will not be described in detail here.

[0057] The tin content of the low tin tin plate is 0.5-1.1g / m 2 ; When the orientation degree of the tin-iron alloy layer FeSn2 on the crystal plane (002) is in the range of 1.0-1.3, it is a dominant orientation; when the orientation degree of the tin-iron alloy layer FeSn2 on the crystal plane (202) is in the range of 1.0-1.3, it is a dominant orientation; when the orientation degree of the tin-iron alloy layer FeSn2 on the crystal plane (002) and the crystal plane (202) is less than 1, both are unfavorable orientations.

[0058] The low-tin tin-plated sheet is immersed in a sodium chloride saline solution for 12 hours. The pH value of the sodium chloride saline solution is 6-7, the concentration is 5%, and the average temperature is 35°C. The low-tin tin-plated sheet has no rust spots and has good corrosion resistance.

[0059] Embodiment 1:

[0060] Step 1: The cold-rolled steel strip substrate is electrolytically degreased by a cathode electrolytic degreasing method to remove residual oil stains on the surface of the cold-rolled steel strip substrate.

[0061] The electrolyte of the cathode electrolytic degreasing method includes 50g / L NaOH solution, 3g / L sodium carboxylate and 1g / L polyether modified silicone oil. The temperature of the cathode electrolytic degreasing method is 50℃, the time is 2s, and the electrolytic current density is 10A / dm 2 .

[0062] Step 2: The cold-rolled steel strip substrate is pickled for 2 seconds using a pickling solution prepared by mixing a 7 g / L nitric acid solution and a 20 g / L phosphoric acid solution to remove an oxide film on the surface of the cold-rolled steel strip substrate.

[0063] Step 3: Electroplating tin on the pickled cold-rolled steel strip substrate with an electroplating tin solution.

[0064] The electroplating tin solution can be a methanesulfonate plating solution, and 3 ml / L of hydroxybenzenesulfonic acid solution and 2 ml / L of salicylic acid solution are added to the electroplating tin solution. 2+ The concentration is 20g / L. The current of electroplating tin is 8A / dm 2 , the temperature of the electroplating tin solution is 55°C.

[0065] Step 4: At room temperature, the cold-rolled steel strip substrate after electroplating tin is fluxed with a flux mixed with 15 ml / L phenolsulfonic acid solution, 15 ml / L sulfosalicylic acid solution and 2 ml / L alkyl glucoside solution, and then cleaned and dried to make a low-tin tin-plated plate.

[0066] Step 5: Soft-melt the low-tin tin-plated plate to form an alloy layer, and perform post-treatment processes such as passivation and oiling.

[0067] The low tin content tin-plated plate of this embodiment was tested by SEM (Scanning Electron Microscope). The SEM test results are shown in the attached figure. Figure 3 and attached Figure 4 As shown. Figure 3 It can be seen that the surface of low-tin tin-plated sheets is relatively flat, without obvious ridge-shaped, hole-shaped and other surface defects, and no rolling marks on the surface. Figure 4 It can be seen that the dendrites of the alloy layer of the low-tin tinplate grow densely, and the dendrites grow in clusters, showing a dense cross-interlaced shape.

[0068] Embodiment 2:

[0069] Step 1: The cold-rolled steel strip substrate is electrolytically degreased by a cathode electrolytic degreasing method to remove residual oil stains on the surface of the cold-rolled steel strip substrate.

[0070] The electrolyte of the cathode electrolytic degreasing method includes 80g / L NaOH solution, 3g / L sodium sulfonate and 1g / L polyether modified silicone oil. The temperature of the cathode electrolytic degreasing method is 60℃, the time is 3s, and the electrolytic current density is 10A / dm 2 .

[0071] Step 2: The cold-rolled steel strip substrate is pickled for 3 seconds using a pickling solution prepared by mixing a 4 g / L nitric acid solution and a 30 g / L phosphoric acid solution to remove an oxide film on the surface of the cold-rolled steel strip substrate.

[0072] Step 3: Electroplating tin on the pickled cold-rolled steel strip substrate with an electroplating tin solution.

[0073] The electroplating tin solution can be a methanesulfonate plating solution, and 9 ml / L of hydroxybenzenesulfonic acid solution and 4 ml / L of salicylic acid solution are added to the electroplating tin solution.2+ The concentration is 20g / L. The current of electroplating tin is 8A / dm 2 , the temperature of the electroplating tin solution is 65℃.

[0074] Step 4: At room temperature, the cold-rolled steel strip substrate after electroplating tin is fluxed with a flux mixed with 27 ml / L phenolsulfonic acid solution, 14 ml / L sulfosalicylic acid solution and 2 ml / L alkyl glucoside solution, and then cleaned and dried to make a low-tin tin-plated plate.

[0075] Step 5: Soft-melt the low-tin tin-plated plate to form an alloy layer, and perform post-treatment processes such as passivation and oiling.

[0076] The low tin content tinplate of this embodiment was tested by SEM. The SEM test results are shown in the attached figure. Figure 5 and attached Figure 6 As shown. Figure 5 It can be seen that the surface of low-tin tin-plated sheets is relatively flat, without obvious ridge-shaped, hole-shaped and other surface defects, and no rolling marks on the surface. Figure 6 It can be seen that the dendrites of the alloy layer of the low-tin tinplate grow densely, and the dendrites grow in clusters, showing a dense cross-interlaced shape.

[0077] The low tin content tin-plated plates of Example 1 and Example 2 were subjected to XRD (diffraction of x-rays, X-ray diffraction) test. The XRD test results are shown in the attached Figure 1 and attached Figure 2 As shown, the solid line represents the XRD test result of Example 1, and the dotted line represents the XRD test result of Example 2.

[0078] From the attached Figure 1 It can be seen that Sn(400) represents the diffraction peak of tin at the crystal plane (400), Sn(200) represents the diffraction peak of tin at the crystal plane (200), and Fe(200) represents the diffraction peak of iron at the crystal plane (200).

[0079] From the attached Figure 2 It can be seen that there is no difference in the crystal plane index between Example 1 and Example 2. From the local diffraction peak spectrum of the solid line, it can be seen that the intensity of Sn on the (400) crystal plane is much higher than the intensity of Fe on the crystal plane (200), indicating that the growth of Sn (400) on the surface of the low-tin tin-plated plate produced in Example 1 is good. From the local diffraction peak spectrum of the dotted line, it can be seen that the intensity of Sn on the crystal plane (400) is lower than the intensity of Fe on the crystal plane (200), indicating that the growth of Sn (400) on the surface of the low-tin tin-plated plate produced in Example 2 is general, but the production of Sn on the crystal plane (200) and the crystal plane (400) has no obvious effect on the product performance.

[0080] According to the above test results, the grain orientation degree TC of the low-tin tin-plated plates of Example 1 and Example 2 is calculated using the following formula:

[0081] Among them, I hkl is the crystal peak intensity of the target peak, I hkl The value can be obtained from the attached Figure 1 and attached Figure 2 Read in.

[0082] I 0 hkl is the diffraction peak intensity of the standard sample, divided by element, I 0 hkl The corresponding values ​​are: Sn is 100, Fe is 50, and FeSn2 is 80.

[0083] n is the number of diffraction peaks, i.e. the calibrated indices of different crystal planes. For example, the number of different diffraction peaks of the crystal plane (200) can be obtained from the attached Figure 1 and attached Figure 2 Get the number of diffraction peaks.

[0084] The calculation results of the grain orientation degree TC of the low-tin tin-plated sheets produced in Example 1, Example 2 and the comparative example are shown in Table 1. The low-tin tin-plated sheets in the comparative example are produced by using the existing process.

[0085] Table 1 Grain orientation degree TC of low tin content tinplate of Example 1, Example 2 and Comparative Example

[0086]

[0087] As can be seen from Table 1, in Examples 1 and 2, the orientation degrees of the tin-iron alloy layer FeSn2(002) and FeSn2(202) are both within 1.0-1.3, which are the dominant orientations. In the comparative examples, no tin-iron alloy layer FeSn2(112) was found, so the orientation degrees thereof are all 0, which is less than 1.0, and are the unfavorable orientations.

[0088] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate, characterized in that: The following steps are involved: Step 1: Electrolytically degreasing the cold-rolled steel strip substrate; Step 2: pickling the cold-rolled steel strip substrate with a pickling solution to remove the oxide film on the surface of the cold-rolled steel strip substrate; Step 3: electroplating tin on the pickled cold-rolled steel strip substrate with an electroplating tin solution; The electro-tin plating solution is a methyl sulfonate plating solution, and a grain orientation control agent is added to the electro-tin plating solution; The grain orientation control agent is prepared by mixing a hydroxybenzenesulfonic acid solution and a salicylic acid solution; Step 4: Use flux to flux the cold-rolled steel strip substrate after electroplating tin, and then clean and dry it to make a low-tin tin-plated plate; The flux is prepared by mixing phenolsulfonic acid solution, sulfosalicylic acid solution and alkyl glucoside solution; Step 5: Soft-melt the low-tin tin-plated plate to form an alloy layer, and perform passivation and oiling processes; The tin content of the low tin tin plate is 0.5-1.1g / m 2 .

2. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: In the step 1, the cold-rolled steel strip substrate is electrolytically degreased by a cathode electrolytic degreasing method; The electrolyte of the cathode electrolytic degreasing method includes NaOH solution, anionic surfactant and defoaming agent; The temperature of the cathode electrolytic degreasing method is 45-60°C, the time is 2-5s, and the electrolytic current density is 10-15A / dm 2 .

3. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 2, characterized in that: The concentration of the NaOH solution is 40-80 g / L; the concentration of the anionic surfactant is 2-7 g / L, and the anionic surfactant is one of carboxylic acid sodium salt, sulfonic acid sodium salt or sulfate sodium salt; the concentration of the defoamer is 1-3 g / L, and the defoamer is polyether modified silicone oil.

4. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: In step 2, the pickling solution is a mixture of a nitric acid solution and a phosphoric acid solution, wherein the concentration of the nitric acid solution is 2-7 g / L, and the concentration of the phosphoric acid solution is 20-40 g / L.

5. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: In the step 2, the pickling time is 2-5s.

6. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: In the step 3, the concentration of the hydroxybenzenesulfonic acid solution is 1-10 ml / L, and the concentration of the salicylic acid solution is 2-7 ml / L.

7. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: In the step 3, the Sn in the electroplating tin solution 2+ The concentration is 20-25g / L; the current of electrotin is 8-12A / dm2, and the temperature of the electrotin solution is 55-65℃.

8. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: The concentration of the phenolsulfonic acid solution is 10-50 ml / L, the concentration of the sulfosalicylic acid solution is 5-15 ml / L, and the concentration of the alkyl glucoside solution is 1-5 ml / L.

9. The method for controlling the orientation of grain growth on the surface of a low-tin tin-plated plate according to claim 1, characterized in that: The temperature of the fluxing is room temperature.

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