Composite coated tinplate production process and tinplate

Abstract

The present application relates to a composite-coated tinplate production process and tinplate, including S10, pretreatment: degreasing and pickling the steel substrate; S20, electroplating tin: electroplating tin on the steel substrate, and then rinsing to form a pure tin layer on the surface of the steel substrate; S30, electroplating chromium: electroplating chromium on the surface of the steel substrate that has completed step S20 and rinsing to form a chromium metal layer and a chromium hydrate oxide layer on the surface of the pure tin layer; S40, oiling: oiling the surface of the steel substrate that has completed step S30 to form an oil film layer. The tinplate production process and the tinplate formed by the process have a tin-chromium composite coating. Based on the excellent anti-corrosion performance of metallic chromium, the chrome-plated layer on the outer surface mainly plays an anti-corrosion role. At the same time, the tin in the inner layer has good welding performance and plays a role as a flux when welding is required, ensuring the welding quality during canning, so that the chrome-plated iron can also be used to make three-piece cans, and reducing costs.

Description

[Technical field]

[0001] The present application relates to the technical field of tinplate, and in particular to a production process of composite-coated tinplate and tinplate. [Background technology]

[0002] Tinplate products are the common names of cold-rolled thin steel plate electroplated tin products and cold-rolled thin steel plate electroplated chrome products in China. These two products are similar in use. Their main use is as food packaging materials. They are made into cans, boxes, lids, etc. for food and beverage packaging. Their non-toxicity, freshness preservation, long-term and recyclable properties make them the best metal packaging materials for food that humans have found so far. Generally, electroplated tin steel plate products are produced by stamping to produce two-piece cans, and by welding to produce three-piece cans.

[0003] Compared with the electroplated chrome steel sheet of the same area, the electroplated tin steel sheet requires a thicker tin metal coating to meet the corrosion protection requirements, and the consumption of metal tin is relatively large; on the other hand, since metal tin needs to be added to the plating solution of the electroplated tin, only chromium salt needs to be added to the plating solution of the electroplated chrome steel sheet, which is cheaper. Therefore, in general, the price of the electroplated chrome steel sheet is cheaper than that of the electroplated tin steel sheet. However, in terms of use, due to the good welding performance of the coated metal tin, the use of the electroplated tin steel sheet is more extensive than that of the electroplated chrome steel sheet; not only can two-piece can containers be produced by stamping, but also three-piece can containers can be produced by welding. However, the electroplated chrome steel sheet is difficult to weld by conventional methods due to the coating metal chromium, which affects its use. Whether it is possible to combine the advantages of the above two products to develop a new tinplate product has become a direction of attempt and research for producers. [Summary of the invention]

[0004] The purpose of the present application is to provide a composite-coated tinplate production process and tinplate. The tinplate production process and the tinplate formed by the process have a tin-plated chrome-plated composite coating, based on the excellent anti-corrosion performance of metallic chromium, the chrome-plated layer on the outer surface mainly plays an anti-corrosion role, while the tin in the inner layer has good welding performance, and plays a role of flux when welding is required, ensuring the welding quality during canning, so that the chrome-plated iron can also be used to make three-piece cans, and reducing the cost.

[0005] This application is implemented through the following technical solutions:

[0006] The production process of composite coated tinplate includes:

[0007] S10, pretreatment: degreasing and pickling the steel substrate;

[0008] S20, electroplating tin: electroplating tin on the steel substrate, followed by rinsing to form a pure tin layer on the surface of the steel substrate;

[0009] S30, electroplating chromium: electroplating chromium on the surface of the steel substrate after step S20 and rinsing, so as to form a chromium metal layer and a chromium hydrated oxide layer on the surface of the pure tin layer;

[0010] S40, oiling: applying oil to the surface of the steel substrate after completing step S30 to form an oil film layer.

[0011] In the above-mentioned composite-coated tinplate production process, the single-side tinning amount in the electroplating step is 0.15-1.0 g / m 2 .

[0012] In the tinplate production process of the composite coating as described above, the concentration of the plating solution in the chromium electroplating step is 80-120 g / L of CrO3, and the chromium plating amount on one side is 30-90 mg / m 2 .

[0013] In the above-mentioned composite coated tinplate production process, the single-side oil coating amount in the oil coating step is 20 to 200 mg / m 2 . .

[0014] The composite-coated tinplate production process as described above further includes the following steps between step S20 and step S30:

[0015] S21, soft melting: the tin-plated steel substrate is heated to above 232°C to melt the tin-plated layer on the surface of the steel substrate, so that the melted tin-plated layer is leveled to produce a bright surface, and a tin-iron alloy layer is formed between the steel substrate and the pure tin layer.

[0016] The tinplate production process of the composite coating as described above, wherein the steel substrate is a strip steel, further comprises the following steps before step S10:

[0017] S09, Entry Section: The steel coil is opened and processed to form strip steel.

[0018] The present application also provides tinplate, comprising a steel substrate, the surface of which is provided with a tin-iron alloy layer, a pure tin layer, a chromium metal layer, a chromium hydrate oxide layer and an oil film layer in sequence from the inside to the outside.

[0019] As for the tinplate described above, the thickness of the steel substrate is 0.12-0.35 mm, the thickness of the tin-iron alloy layer is 0.08-0.12 um, the thickness of the pure tin layer is 0.15-1 um, the thickness of the chromium metal layer is 0.003-0.009 um, the thickness of the chromium hydrate oxide layer is 0.004 um, and the thickness of the oil film layer is 0.002 um.

[0020] Compared with the prior art, this application has the following advantages:

[0021] The tinplate production process and the tinplate formed by the process have a tin-plated chrome-plated composite coating. Based on the excellent anti-corrosion performance of metallic chromium, the chrome-plated layer on the outer surface mainly plays an anti-corrosion role. At the same time, the tin in the inner layer has good welding performance and plays a role of flux when welding is required, thereby ensuring the welding quality during canning, so that the chrome-plated iron can also be used to make three-piece cans, and the cost is reduced.

Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a process flow chart of Example 1 of the present application.

[0024] Figure 2 This is the process flow chart of Example 2 of the present application.

[0025] Figure 3 This is the process flow chart of Example 3 of the present application.

[0026] Figure 4 This is a process flow chart of Example 4 of the present application.

[0027] Figure 5 This is a schematic diagram of the cross-sectional structure of the tinplate described in Example 5 of the present application. [Specific implementation method]

[0028] In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] Example 1

[0030] like Figure 1 As shown, the embodiment of the present application proposes a composite-coated tinplate production process, which includes:

[0031] S09, inlet section: opening the steel coil and processing it to form a steel strip, using the steel strip as the steel matrix 1;

[0032] S10, pretreatment: degreasing and pickling the steel substrate 1 to remove stains such as oil stains and rust on the surface of the steel substrate 1.

[0033] S20, electroplating tin: electroplating tin on the steel substrate 1, and then rinsing to form a pure tin layer 3 on the surface of the steel substrate 1, wherein the single-side tin plating amount of the electroplated tin is 0.15-1.0 g / m 2 , which is much less than the general electroplated tin steel sheet. The best tin-plated steel sheet specification is E2.8, that is, the single-sided tin-plated amount is set to 2.8g / m 2 ; In some special cases, it is set to 1.0g / m 2 The amount of tin plating. Too little tin plating will seriously affect the corrosion resistance of the electroplated tin steel sheet. The electroplated tin steel sheet in this process will be chrome-plated in the subsequent process, and the outer chrome plating layer plays an anti-corrosion role, so the amount of metal tin can be significantly reduced.

[0034] S21, soft melting: the tin-plated steel substrate 1 is heated to above 232°C to melt the tin-plated layer on the surface of the steel substrate 1, so that the melted tin-plated layer is leveled to produce a bright surface. A part of the metallic tin in the tin-plated layer will react with the metallic iron under heating conditions to form an intermetallic compound tin-iron alloy layer 2.

[0035] S30, one-step electroplating chromium: electroplating chromium on the surface of the steel substrate 1 after step S20 and rinsing to form a chromium metal layer 4 and a chromium hydrated oxide layer 5 on the surface of the pure tin layer 3, wherein the concentration of the plating solution in the chromium plating step is 80-120 g / L CrO3. One-step chromium plating is to produce metallic chromium and chromium hydrated oxide simultaneously during the electroplating process. This one-step chromium plating method can save the investment in chromium plating equipment and has certain economic value.

[0036] Its advantages are that, on the one hand, the concentration of the plating solution is lower than that of the general electrochromium plating solution, which reduces the difficulty of operation; on the other hand, since the anti-corrosion function is completed by the tin plating layer and the chromium plating layer, the thickness of the chromium plating layer can be reduced, and the metal chromium layer can be selected to be 30-90 mg / m 2 On the other hand, during chromium electroplating, chromium hydrate oxides will be produced on the surface of the chromium-plated layer, and the pores of the metallic chromium layer can be closed by the amorphous chromium hydrate oxides, thereby improving corrosion resistance.

[0037] S40, oiling: oiling the surface of the steel substrate 1 after step S30 to form an oil film layer 6, wherein the amount of oil applied on one side is 20-200 mg / m 2 .

[0038] The tinplate production process proposed in this embodiment performs a chrome plating process on the surface after the tin plating process is completed to produce a tin-plated and chrome-plated composite tinplate product. Based on the excellent anti-corrosion performance of metallic chromium, the chrome plating layer on the outer surface mainly plays an anti-corrosion role, and the tin in the inner layer has good welding performance and acts as a flux when welding is required, ensuring the welding quality during canning, so that the chrome-plated iron can also be used to make three-piece cans, and reducing costs. The one-step chrome plating method can save investment in chrome plating equipment. It has certain economic value.

[0039] Example 2

[0040] like Figure 2 As shown, the embodiment of the present application proposes a composite-coated tinplate production process, which includes:

[0041] S09, inlet section: opening the steel coil and processing it to form a steel strip, using the steel strip as the steel matrix 1;

[0042] S10, pretreatment: degreasing and pickling the steel substrate 1.

[0043] S20, electroplating tin: electroplating tin on the steel substrate 1, and then rinsing to form a pure tin layer 3 on the surface of the steel substrate 1, wherein the single-side tin plating amount of the electroplated tin is 0.15-1.0 gg / m 2 .

[0044] S21, soft melting: the tin-plated steel substrate 1 is heated to above 232°C to melt the tin-plated layer on the surface of the steel substrate 1, so that the melted tin-plated layer is leveled to produce a bright surface, and a tin-iron alloy layer 2 is formed between the steel substrate 1 and the pure tin layer 3.

[0045] S30, two-step electroplating chromium: electroplating chromium on the surface of the steel substrate 1 after step S20 and rinsing to form a chromium metal layer 4 and a chromium hydrate oxide layer 5 on the surface of the pure tin layer 3, wherein the concentration of the electroplating solution in the electroplating chromium step is 80-120 g / L CrO3, and the single-side chromium plating amount is 30-90 mg / m 2 .

[0046] Compared with Example 1, the two-step chromium plating method uses two plating solutions to complete the chromium plating process. The steel substrate generates metallic chromium in the first plating solution, and chromium hydrate oxide is resolved in the second plating solution. The advantages of the two-step chromium plating method are that since two different plating solutions are used to complete the metallic chromium plating and the generation of chromium hydrate oxide in two steps, the process requirements and the difficulty of the generation operation are reduced.

[0047] S40, oiling: oiling the surface of the steel substrate 1 after step S30 to form an oil film layer 6, wherein the amount of oil applied on one side is 20-200 mg / m 2 .

[0048] Example 3

[0049] like Figure 3 As shown, the embodiment of the present application proposes a composite-coated tinplate production process, which includes:

[0050] S09, inlet section: opening the steel coil and processing it to form a steel strip, using the steel strip as the steel matrix 1;

[0051] S10, pretreatment: degreasing and pickling the steel substrate 1.

[0052] S20, electroplating tin: electroplating tin on the steel substrate 1, and then rinsing to form a pure tin layer 3 on the surface of the steel substrate 1, wherein the single-side tin plating amount of the electroplated tin is 0.15-1.0 gg / m 2 .

[0053] S30, one-step electroplating chromium: electroplating chromium on the surface of the steel substrate 1 after step S20 and rinsing to form a chromium metal layer 4 and a chromium hydrate oxide layer 5 on the surface of the pure tin layer 3, wherein the concentration of the electroplating solution in the electroplating chromium step is 80-120 g / L CrO3, and the single-side chromium plating amount is 30-90 mg / m 2 .

[0054] S40, oiling: oiling the surface of the steel substrate 1 after step S30 to form an oil film layer 6, wherein the amount of oil applied on one side is 20-200 mg / m 2 .

[0055] Compared with Example 1, the present embodiment omits the reflow process. Due to the absence of the reflow process, the metal tin of the tin-plated layer will be in the form of particles. On this layer of tin particles, chrome is plated in one step to obtain a composite coating with a gravel-like matte appearance, which has a good application effect in certain packaging occasions. At the same time, since the reflow equipment is omitted, the equipment investment will be greatly reduced.

[0056] Example 4

[0057] like Figure 4 As shown, the embodiment of the present application proposes a composite-coated tinplate production process, which includes:

[0058] S09, inlet section: opening the steel coil and processing it to form a steel strip, using the steel strip as the steel matrix 1;

[0059] S10, pretreatment: degreasing and pickling the steel substrate 1.

[0060] S20, electroplating tin: electroplating tin on the steel substrate 1, and then rinsing to form a pure tin layer 3 on the surface of the steel substrate 1, wherein the single-side tin plating amount of the electroplated tin is 0.15-1.0 g / m 2 .

[0061] S30, two-step electroplating chromium: electroplating chromium on the surface of the steel substrate 1 after step S20 and rinsing to form a chromium metal layer 4 and a chromium hydrate oxide layer 5 on the surface of the pure tin layer 3, wherein the concentration of the electroplating solution in the electroplating chromium step is 80-120 g / L CrO3, and the single-side chromium plating amount is 30-90 mg / m 2 .

[0062] S40, oiling: oiling the surface of the steel substrate 1 after step S30 to form an oil film layer 6, wherein the amount of oil applied on one side is 20-200 mg / m 2 .

[0063] Compared with Example 3, this embodiment adopts a two-step electroplating method for chromium, and can also obtain a composite coating with a gravel-like surface and a matte appearance, which has a good application effect in certain packaging occasions. The process requirements and difficulty of the chromium plating operation will be reduced.

[0064] Example 5

[0065] like Figure 5 As shown, this embodiment provides a tinplate, including a steel substrate 1, wherein the surface of the steel substrate 1 is provided with a tin-iron alloy layer 2, a pure tin layer 3, a chromium metal layer 4, a chromium hydrated oxide layer 5 and an oil film layer 6 in sequence from the inside to the outside. Specifically, the thickness of the steel substrate 1 is 0.12-0.35 mm, the thickness of the tin-iron alloy layer 2 is 0.08-0.12 um, the thickness of the pure tin layer 3 is 0.15-1 um, the thickness of the chromium metal layer 4 is 0.003-0.009 um, the thickness of the chromium hydrated oxide layer 5 is 0.004 um, and the thickness of the oil film layer 6 is 0.002 um.

[0066] The tinplate proposed in this embodiment has a composite coating of a tin plating layer and a chromium layer. Based on the excellent anti-corrosion performance of metallic chromium, the chrome plating layer on the outer surface mainly plays an anti-corrosion role, and the tin in the inner layer has good welding performance and acts as a flux when welding is required, thereby ensuring the welding quality during canning, so that chrome-plated iron can also be used to make three-piece cans, and reducing costs.

[0067] As described above, one or more implementation methods are provided in combination with specific contents, and the specific implementation of this application is not limited to these descriptions. Any similarity or similarity with the method, structure, etc. of this application, or some technical deductions or replacements made based on the concept of this application should be considered as the protection scope of this application.

Claims

1. A composite coated tinplate production process, characterized in that: include: S10, pretreatment: degreasing and pickling the steel substrate (1); S20, electroplating tin: electroplating tin on the steel substrate (1), followed by rinsing to form a pure tin layer (3) on the surface of the steel substrate (1); S30, electroplating chromium: electroplating chromium on the surface of the steel substrate (1) after completing step S20 and rinsing, so as to form a chromium metal layer (4) and a chromium hydrate oxide layer (5) on the surface of the pure tin layer (3); S40, oiling: applying oil to the surface of the steel substrate (1) after completing step S30 to form an oil film layer (6); The following steps are also included between step S20 and step S30: S21, soft melting: heating the tin-plated steel substrate (1) to a temperature above 232° C. to melt the tin-plated layer on the surface of the steel substrate (1), so that the melted tin-plated layer is leveled to produce a bright surface, and a tin-iron alloy layer (2) is formed between the steel substrate (1) and the pure tin layer (3); The prepared tinplate comprises a steel substrate (1), wherein the surface of the steel substrate (1) is provided with a tin-iron alloy layer (2), a pure tin layer (3), a chromium metal layer (4), a chromium hydrate oxide layer (5) and an oil film layer (6) in sequence from the inside to the outside; The thickness of the steel substrate (1) is 0.12-0.35 mm, the thickness of the tin-iron alloy layer (2) is 0.08-0.12 μm, the thickness of the pure tin layer (3) is 0.15-1 μm, the thickness of the chromium metal layer (4) is 0.003-0.009 μm, the thickness of the chromium hydrate oxide layer (5) is 0.004 μm, and the thickness of the oil film layer (6) is 0.002 μm.

2. The composite-coated tinplate production process according to claim 1, characterized in that: The single-sided tinning amount in the electroplating step is 0.15 to 1.0 g / m 2 .

3. The composite-coated tinplate production process according to claim 1, characterized in that: The concentration of the electroplating solution in the chromium electroplating step is 80-120 g / L of CrO3, and the amount of chromium plating on one side is 30-90 mg / m 2 .

4. The composite coated tinplate production process according to claim 1, characterized in that: The amount of oil applied on one side during the oiling step is 20 to 200 mg / m 2 .

5. The composite-coated tinplate production process according to claim 1, characterized in that: The steel substrate (1) is a strip steel, and the step S10 further includes the following steps: S09, Entry Section: The steel coil is opened and processed to form strip steel.

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