Ultrahigh-corrosion-resistance coated steel plate with good formability and preparation method of ultrahigh-corrosion-resistance coated steel plate

Abstract

The invention discloses an ultrahigh corrosion-resistant coated steel plate with good formability and a preparation method thereof. The ultrahigh corrosion-resistant coated steel plate comprises a substrate and a plating layer, the plating layer is of a double-layer structure, the first layer is an electroplated layer, the second layer is a hot-dip plating layer, the electroplated layer comprises the following components in percentage by weight: 0.5-1% of Si and the balance of Al, and the hot-dip plating layer comprises the following components in percentage by weight: 5-15% of Al, 3-8% of Mg, 0.5-0.9% of Si and the balance of Zn. According to the invention, through matrix design, double-layer coating structure design, coating component design and control of an electroplating process, a heating process and a cooling process after plating, a proper structure and phase structure are obtained, the prepared steel plate has good corrosion resistance and processability, the corrosion resistance can reach 5-20 times of that of a pure zinc product with the same specification, and the corrosion resistance can reach 5-20 times of that of a pure zinc product with the same specification. And the crack width after 0T bending processing is less than or equal to 20 microns, so that the improvement of corrosion resistance and the balance control of forming performance are realized.

Description

Technical Field

[0001] This invention belongs to the technical field of coating products, specifically relating to an ultra-high corrosion-resistant coated steel sheet with good formability and its preparation method. Background Technology

[0002] Zinc-aluminum-magnesium (ZAMg) products are widely used in construction, photovoltaics, and other fields due to their excellent corrosion resistance. However, existing ZAMg products cannot meet the corrosion resistance requirements in C5 and above environments. In recent years, ultra-high corrosion-resistant ZAMg products such as 19Al6Mg and 12Al5Mg have been developed abroad. However, with the increase of Mg content, the proportion of MgZn2 phase in the coating structure increases accordingly. Since the MgZn2 phase is a brittle phase, it leads to a deterioration in the coating's formability.

[0003] Domestic patent application CN 116426793 A discloses a high corrosion-resistant zinc-aluminum-magnesium coated steel sheet and its preparation method. This application adds elements such as Mg, Al, and Si to the zinc-aluminum-magnesium alloy coating, controlling the mass fraction of Mg in the coating to be 3-8% and the mass fraction of Al to be 12-25%, ensuring that the volume fraction of Mg-Zn compounds on the coating surface does not exceed 2%, and controlling the ratio of Si to Al content in the coating to be within 0.05-0.15. This results in a zinc-aluminum-magnesium coated steel sheet with good corrosion resistance and excellent surface quality. However, this technology has a relatively low proportion of Mg-Zn compounds, limiting the improvement in corrosion resistance.

[0004] Domestic patent application CN 114846171 A discloses a hot-dip galvanized alloy steel with excellent corrosion resistance and its manufacturing method. The hot-dip galvanized alloy coating contains: Al: more than 8% to 25%, Mg: more than 4% to 12%, and the balance Zn and other unavoidable impurities. The surface X-ray diffraction intensity of the hot-dip galvanized alloy coating satisfies the following relationship 1: [Relationship 1] 2000cps ≤ X-ray diffraction intensity ≤ 20000cps (wherein, the X-ray diffraction intensity is MN, M refers to the highest peak intensity in the range of 2θ = 20.00° to less than 21°, and N refers to the peak intensity at 2θ = 20.00°). However, in this application, the Al content reaches a maximum of 25%, and the Mg content reaches a maximum of 12%, making surface quality control extremely difficult in production. Furthermore, the high MgZn2 content makes it difficult to control the forming performance.

[0005] To improve the corrosion resistance of steel plates using existing technologies, the following methods are mainly employed: 1) Increasing the Al and Mg content, but without controlling the proportion of the eutectic phase, resulting in limited improvement in corrosion resistance; 2) Increasing the Al and Mg content, while also increasing the proportion of the eutectic phase, but resulting in insufficient formability. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing an ultra-high corrosion-resistant coated steel sheet with excellent formability and its preparation method, achieving a balanced control between improved corrosion resistance and formability.

[0007] To achieve the above objectives, the present invention provides an ultra-high corrosion-resistant coated steel sheet with good formability, comprising a substrate and a coating; wherein the coating has a double-layer structure, the first layer (inner layer, i.e., the layer in direct contact with the substrate) is an electroplated layer, and the second layer (outer layer) is a hot-dip galvanized layer. The electroplated layer comprises 0.5-1% Si and the balance Al by weight percentage, and the hot-dip galvanized layer comprises 5-15% Al, 3-8% Mg, 0.5-0.9% Si and the balance Zn by weight percentage.

[0008] Furthermore, the hot-dip coating comprises an Al-rich phase, a MgZn binary alloy phase, a Mg2Si phase, and a Zn-Al-MgZn2 ternary eutectic phase.

[0009] Furthermore, the hot-dip coating comprises, by weight percentage: 20-30% MgZn binary alloy phase, 20-30% Al-rich phase, 0.1-0.2% Mg2Si phase, and 35-55% Zn-Al-MgZn2 ternary eutectic phase.

[0010] Furthermore, the Al-rich phase is divided into two parts, A and B. Part A is located at the junction of the electroplated layer and the hot-dip plating layer, and part B is located within the hot-dip plating layer. The weight ratio of A to B satisfies: 2≤B / A≤5.

[0011] Furthermore, the microstructure of the matrix is ​​equiaxed ferrite.

[0012] A method for preparing ultra-high corrosion-resistant coated steel sheet as described above is also provided. The preparation method includes the following steps in sequence: substrate electrolytic degreasing, pickling activation, electroplating, cleaning, hot air drying, heating, hot-dip plating, and cooling. In the electroplating step, the electroplating solution comprises, by weight percentage, 20-35% 1-ethyl-3-methylimidazolium chloride, 65-75% aluminochloroaluminate, 1-3% aluminosilicate, 0.5-1% benzoic acid, and 1-2% polyethylene glycol. The content of 1-ethyl-3-methylimidazolium chloride is defined as a, the content of aluminochloroaluminate as b, and the content of aluminosilicate as c. a, b, and c satisfy the relationship: 1.68 ≤ (b+c) / a ≤ 3.37.

[0013] Furthermore, the pickling and activation solution of the substrate is a 10-30% HCl solution, and the activation temperature is 40-60℃; the electroplating current density is 0.5-2 A / dm², the electroplating temperature is 30-50℃, and the electroplating pH value is 3-5.

[0014] Furthermore, the cleaning process is divided into three stages: the first stage is rinsing with hot water at 60-80℃ for 1-2 minutes; the second stage is rinsing with flowing room temperature water with a conductivity ≤50μS / cm; and the third stage is rinsing with ultrapure water with a resistivity of 5-10MΩ·cm. After cleaning, the water is dried with hot air.

[0015] Furthermore, the heating temperature is 380-420℃, the heating time is 1-5 minutes, and a 5-10% hydrogen atmosphere is used for protection during the heating process; the hot-dip plating temperature is 400-490℃.

[0016] Furthermore, the cooling process employs a two-stage cooling method. The first stage has a cooling rate of 40-50℃ / s and a cooling end temperature of 335-350℃. The second stage has a cooling rate of 1-10℃ / s and a cooling end temperature of 200-250℃.

[0017] (1) This invention achieves ultra-high corrosion resistance by forming a multi-layer structure through coating design. When the steel plate comes into contact with corrosion agents (O2, Cl... - In this process, the outermost hot-dip coating forms the first layer of protection. On the one hand, the corrosion resistance is improved by controlling the Al and Mg content of the coating. When the Al content is too low, the improvement in corrosion resistance is not ideal. When the Al content is too high, coarse aluminum-rich phases are formed, which deteriorates the corrosion resistance. Therefore, the Al content is controlled in the range of 5-15% in this invention. When the Mg content is too low, the improvement in corrosion resistance is limited. When the Mg content is too high, too much MgZn phase will disrupt the phase balance. Therefore, the Mg content in the coating of this invention is controlled in the range of 3-8%. On the other hand, the corrosion resistance is further improved by controlling the microstructure of the hot-dip coating. First, controlling the proportion of the MgZn phase to above 20% can improve the cathodic protection effect of the coating. Further controlling the proportion of the ternary eutectic phase to above 35% promotes the formation of a dense basic zinc carbonate film, achieving self-repair and blocking corrosion diffusion. Furthermore, controlling the formation of trace amounts of Mg2Si in the coating can inhibit the coarsening of the MgZn phase and improve corrosion resistance. However, excessive Mg2Si hinders the formation of dense corrosion products such as Mg(OH)2, affecting corrosion resistance. Therefore, this invention controls the Mg2Si phase proportion to 0.1-0.2%. Secondly, the electroplated Al layer forms a second layer of protection. When the hot-dip coating is damaged, the aluminum coating oxidizes to form a new Al2O3 film, automatically sealing the damaged area and preventing further corrosion spread.

[0018] Trace amounts of Mg2Si preferentially precipitate out of grain boundaries or eutectic regions during solidification, and can serve as heterogeneous nucleation sites to refine the eutectic structure, thereby inhibiting the growth of the MgZn2 phase into a coarse skeletal structure in the continuous eutectic liquid film.

[0019] 2-3 mg / L needs to be dissolved within the initial 0-2 hours of corrosion. -1 Mg2+ Talent and Al 3+ Zn 2+ Co-precipitate as Zn6Al2(OH) 16 CO3·4H2O (LDH) membrane; when Mg2Si < 0.1%, the available active Mg surface area is < 0.3 cm². 2 cm -2 Mg in solution 2+ Peak concentration is only 0.8 mg / L -1 Insufficient to form a complete LDH layer, it instead generates a loose ZnO / Zn5(CO3)2(OH)6, resulting in a decrease in film resistance by an order of magnitude (R_f from 8kΩ cm⁻¹). 2 Reduced to 1 kΩ cm 2 (The following) It cannot self-repair in the later stages, and the weightlessness from salt spray increases by 40% after 96 hours.

[0020] 0.1-0.2% Mg₂Si can be slightly dissolved by weak acid-neutral electrolytes in the early stages of corrosion, continuously providing Mg. 2+ , with Zn 2+ Al 3+ Co-precipitation produces layered double hydroxides (LDHs) and alkaline zinc chloride / aluminum zinc carbonate colloidal films; these products are dense, have high electrical resistance, can block electron transport, and self-heal cracks. LDHs are a type of two-dimensional layered inorganic film composed of alternating stacks of positively charged host layers and negatively charged interlayer anions.

[0021] When Mg₂Si > 0.2%, the particles are dense and have a negative potential, easily forming a large cathode-small anodic couple. This causes a rapid increase in local pH, promoting the growth of Mg₂Si. 2+ Direct precipitation forms a thick and loose Mg(OH)2 outer layer, hindering the inward filling of Zn-Al corrosion products. Simultaneously, excess Si adsorbs on the Mg(OH)2 surface, reducing its subsequent carbonation-densification ability. When controlled at 0.1-0.2%, Mg(OH)2 is embedded only within the LDH membrane in the form of nanolayers, buffering the pH without compromising the overall density of the membrane. This achieves the dual effect of "fine grain suppression of coarsening + appropriate Mg supply for film formation," thus balancing formation and long-life corrosion resistance.

[0022] (2) This invention achieves a balance between ultra-high corrosion resistance and forming performance by controlling the microstructure and proportion of the substrate and coating. First, the Si content in the coating is controlled: a small amount of Si can inhibit the growth of Fe-Al compounds, prevent poor adhesion of the coating due to excessive alloy layer thickness, and improve the uniformity of the eutectic phase; however, if the content is too high, it will increase the brittleness of the electroplated layer and increase the Mg2Si phase in the hot-dip coating, thus increasing the brittleness of the coating and affecting the forming performance. Therefore, this invention controls the Si content in the electroplated layer to be 0.5-1% and the Si content in the hot-dip coating to be 0.5-0.9%. Second, the Al-rich phase in part B can be used as Mg2Zn. 11 Inhibitors of brittle intermetallic compounds reduce stress concentration points and improve coating ductility. Too little Al phase has little effect, while too much increases the difference in tensile coefficient between the Al-rich phase and the eutectic region, generating localized internal stress during forming and causing cracking during bending tests. Therefore, the Al-rich phase (A portion + B portion) in this invention accounts for 20-30%. Furthermore, insufficient MgZn phase content reduces the cathodic protection efficiency of the coating and increases the risk of localized perforation corrosion; excessive MgZn content significantly increases brittleness, affecting stamping performance. Therefore, this invention controls the MgZn phase content to 20-30%. Further controlling the proportion of the ternary eutectic phase is also crucial. The ternary eutectic phase promotes the formation of a dense basic zinc carbonate film, achieving self-repair and blocking corrosion diffusion. Too little ternary eutectic phase has little effect and reduces corrosion resistance; too much ternary eutectic phase forms a continuous network structure, causing localized stress concentration and affecting forming performance. Therefore, this invention controls the ternary eutectic phase proportion to 35-55%. Furthermore, the electroplated aluminum layer undergoes a diffusion reaction at the hot-dip plating temperature. When B / A > 5, the content of the aluminum-rich phase A is too low, resulting in a weak buffering effect against bending deformation; when B / A < 2, the content of the aluminum-rich phase B is too low, leading to insufficient Mg2Zn. 11The formation of eutectic phases increases the brittleness of the coating and reduces its formability. Therefore, this invention controls the relationship between the aluminum-rich phase A at the junction of the electroplated aluminum layer and the hot-dip coating and the aluminum-rich phase B in the hot-dip coating to satisfy 2≤B / A≤5, which can reduce the tendency of coating cracks during bending deformation and improve formability. Further controlling the coating cooling process, at 335-350℃, controlling the cooling rate v to 40-50℃ / s not only promotes the formation of the eutectic phase but also inhibits eutectic phase segregation, reducing the eutectic size and improving corrosion resistance and ductility; simultaneously, at 200-250℃, controlling the cooling rate v to 1-10℃ / s promotes the growth of the eutectic phase. Furthermore, controlling the matrix microstructure to be equiaxed ferrite prevents grain recrystallization at lower heating temperatures, and the equiaxed ferrite microstructure is more conducive to formability. Further control of the heating temperature is achieved at 380-420℃. If the heating temperature is too low, it is not conducive to hot-dip galvanizing. If the heating temperature is too high, the electroplated aluminum layer will partially melt and form liquid aluminum droplets. The molten aluminum will aggregate into spherical particles on the surface of the steel substrate, resulting in the loss of coating continuity. At the same time, the electroplated aluminum layer recrystallizes when heated at 380-420℃, and the original fine grains coarsen, which is beneficial to improving the coating ductility and thus improving the forming performance.

[0023] (3) This invention forms a uniform electroplated aluminum layer through appropriate electroplating solution composition and process design, which forms a good bond with the hot-dip coating and the substrate. First, when the pickling concentration is too low, the activation effect is not ideal; when the pickling concentration is too high, it reacts with the substrate; therefore, this invention controls the pickling activation concentration to 10-30%. Furthermore, if the pickling temperature is too low, the oxide layer is not completely removed; if the pickling temperature is too high, the adhesion of the electroplated layer is reduced; therefore, this invention controls the pickling temperature to 40-60℃. Furthermore, controlling the composition of the electroplating solution to 20-35% of 1-ethyl-3-methylimidazolium chloride provides a stable solution environment, controlling 65-75% of aluminochloride and 1-3% of aluminosilicate to form a suitable electroplating layer composition, while adding 0.5-1% benzoic acid to inhibit steel substrate corrosion, and adding 1-2% polyethylene glycol to improve the coating uniformity. Furthermore, the content of 1-ethyl-3-methylimidazolium chloride is defined as a, the content of chloroaluminate as b, and the content of aluminosilicate as c. When (b+c) / a < 1.68, the adhesion between the coating and the substrate decreases, making it easy to peel off; when (b+c) / a > 3.37, it hinders Al ion deposition and reduces corrosion resistance. Therefore, this invention controls a to satisfy the relationship between b and c: 1.68 ≤ (b+c) / a ≤ 3.37. Furthermore, when the electroplating temperature is too high, the difference in thermal expansion between the substrate and the electroplated layer induces internal stress, reducing the bonding strength and making the electroplated layer easy to peel off; when the electroplating temperature is too low, the ion migration rate decreases, the cathode current efficiency decreases, and the deposition time is prolonged. Therefore, this invention controls the electroplating temperature to be 30-50℃. Furthermore, when the electroplating current density is too low, the aluminum ion reduction rate is slow, resulting in a porous and loose coating; when the electroplating current density is too high, the coating hardness is too high. Therefore, this invention controls the electroplating current density to be 0.5-2 A / dm³. 2 Furthermore, if the electroplating pH value is too low, the internal stress increases, making the electroplated layer prone to peeling; if the electroplating pH value is too high, the stability of the plating solution decreases, hydrogen gas is trapped in the cathode area, and the pinhole rate increases significantly; therefore, this invention controls the electroplating pH value to be 3-5. Furthermore, the first stage of cleaning dissolves organic matter and ionic liquid residues, the second stage of cleaning removes dissolved salts, and the third stage of cleaning thoroughly removes ionic residues. These three stages of cleaning improve the cleanliness of the electroplated layer and increase the adhesion between the electroplated layer and the hot-dip plating layer.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention obtains a suitable microstructure and phase structure by designing the substrate, designing the double-layer coating structure, designing the composition of the coating, and controlling the electroplating process, heating process and post-plating cooling process. The prepared steel plate has good corrosion resistance and processing performance. The corrosion resistance can reach 5-20 times that of pure zinc products of the same specification. The crack width after 0T bending is ≤20μm, thereby achieving a balance between improving corrosion resistance and forming performance. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments.

[0026] The process control of the ultra-high corrosion-resistant coated steel sheet with good formability according to this invention is shown in Tables 1-3. The composition of the substrate is 0.001≤C≤0.25, 0.02≤Mn≤1.5, Si≤0.1, P≤0.02, S≤0.02, Ti≤0.2, Nb≤0.2, V≤0.2, Cr≤0.2, Mo≤0.2, Cu≤0.2, and the balance being Fe. The coating thickness is 60-600 g / m. 2 Double-sided, with an electroplating layer of 10-40g / m 2 / Double-sided, the rest are hot-dip coated.

[0027] Table 1. Coating composition and microstructure control

[0028]

[0029] Table 2 Electroplating composition and process control

[0030]

[0031] Table 3 Heating and Galvanizing Process Control

[0032]

[0033] Table 4 Electroplating Layer Cleaning Process Control

[0034]

[0035] The implementation effect of the ultra-high corrosion-resistant coated steel sheet with good forming performance of the present invention is shown in Table 5.

[0036] Corrosion resistance was compared with that of pure zinc products with the same coating, according to GB / T 10125, with 1-3 times the corrosion resistance being grade 1, 3-5 times being grade 2, 5-10 times being grade 3, 10-15 times being grade 4, and 15-20 times being grade 5. Formability was compared by the crack width after 0T bending.

[0037] Table 5 Corrosion resistance and formability of steel plates

[0038]

[0039] As can be seen from the above, the ultra-high corrosion-resistant coated steel sheet with good forming performance in the embodiments of the technical solution of the present invention has the following characteristics: the proportion of MgZn binary alloy phase is 20-30%, the proportion of Al-rich phase is 20-30% (the Al-rich phase is divided into two parts, A and B, part A is located at the junction of the electroplating layer and the hot-dip coating layer, and part B is located inside the hot-dip coating layer, and the weight ratio of A to B satisfies: 2≤B / A≤5), the proportion of Mg2Si phase is 0.1-0.2%, and the proportion of Zn-Al-MgZn2 ternary eutectic phase is 35-55%. Its corrosion resistance can reach 5-20 times that of pure zinc products of the same specification, and the crack width after 0T bending is ≤20μm. Among them, the Al and Mg content of Comparative Example 1 is relatively low, and its corrosion resistance is 5-10 times that of pure zinc products with the same coating layer. With the increase of Al and Mg content, the corrosion resistance of Example 5 is 15-20 times that of pure zinc products with the same coating layer. In Comparative Example 1, the absence of an electroplated aluminum layer resulted in several drawbacks. First, the buffering effect of bending deformation was weak, leading to poor formability; the 0T bending crack width was 55 μm. Second, when the outermost hot-dip coating was damaged, it failed to provide a second layer of protection, and its corrosion resistance was only 3-5 times that of a pure zinc product with the same coating. In Comparative Example 2, the electroplated layer lacked Si. Without Si, the alloy layer at the interface with the substrate was too thick, resulting in poor bending performance; the 0T bending crack width was 50 μm. In Comparative Example 3, the hot-dip coating had a low Mg content. Insufficient MgZn phase content reduced the cathodic protection effectiveness of the coating and decreased corrosion resistance; its corrosion resistance was only 3-5 times that of a pure zinc product with the same coating. Furthermore, the high initial cooling rate after plating resulted in a ternary eutectic phase ratio exceeding 55%. This excessive ternary eutectic phase formed a continuous network structure, causing localized stress concentration and affecting formability; the 0T bending crack width was 39 μm. In Comparative Example 4, there was less Al-rich phase B and the ratio of Al-rich phase B / A was <2, resulting in less Mg2Zn in the coating. 11The formation of the Al-rich phase increases the brittleness of the coating and reduces its formability. The 0T bending crack width is 35 μm. Simultaneously, the high content of chloroaluminate (the ratio of (chloroaluminate content b + aluminosilicate content c) / 1-ethyl-3-methylimidazolium chloride content a) hinders Al ion deposition, reducing corrosion resistance to only 3-5 times that of pure zinc products with the same coating. In Comparative Example 5, the Al-rich phase A is less abundant and the ratio of Al-rich phase B / A is greater than 5, resulting in weaker buffering effect against bending deformation. Furthermore, the low chloroaluminate content (the ratio of (chloroaluminate content b + aluminosilicate content c) / 1-ethyl-3-methylimidazolium chloride content a) reduces the adhesion between the electroplated layer and the substrate, further decreasing formability. The 0T bending crack width is 32 μm. In Comparative Example 6, the heating temperature was too high, causing localized melting of the electroplated aluminum layer and the formation of liquid aluminum droplets. The molten aluminum aggregated into spherical particles on the steel substrate surface, resulting in a loss of continuity in the electroplated aluminum layer. This affected corrosion resistance and the buffering effect against deformation. Compared to Example 3, the corrosion resistance and formability were reduced, being 5-10 times that of a pure zinc product with the same coating. The 0T bending crack width was 36 μm. In Comparative Example 7, the cooling rate in the first stage of post-plating cooling was too low, reducing the ternary eutectic phase content. Compared to Example 5, the corrosion resistance was reduced, being 10-15 times that of a pure zinc product with the same coating. Simultaneously, the MgZn phase content increased, leading to increased coating brittleness and affecting formability. The 0T bending crack width was 25 μm.

[0040] The above description is only a specific example of the present invention. It should be noted that the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the technical concept and technical solution of the present invention, or the direct application of the technical concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A supercorrosion resistant coated steel sheet having excellent formability, characterized in that: The coating layer is a double-layer structure, the first layer is an electroplating layer, and the second layer is a hot-dip coating layer, the electroplating layer comprises 0.5-1% of Si and the balance of Al in terms of percentage by weight, and the hot-dip coating layer comprises 5-15% of Al, 3-8% of Mg, 0.5-0.9% of Si and the balance of Zn in terms of percentage by weight.

2. The supercorrosion resistant coated steel sheet having excellent formability according to claim 1, characterized in that: The hot-dip coating layer comprises an Al-rich phase, an MgZn binary alloy phase, an Mg2Si phase and a Zn-Al-MgZn2 ternary eutectic phase.

3. The supercorrosion resistant coated steel sheet having excellent formability according to claim 2, characterized in that: In the hot-dip coating layer, the MgZn binary alloy phase accounts for 20-30%, the Al-rich phase accounts for 20-30%, the Mg2Si phase accounts for 0.1-0.2%, and the Zn-Al-MgZn2 ternary eutectic phase accounts for 35-55% in terms of percentage by weight.

4. The supercorrosion resistant coated steel sheet having excellent formability according to claim 2, characterized in that: The Al-rich phase is divided into two parts A and B, the part A is located at the joint of the electroplating layer and the hot-dip coating layer, and the part B is located in the hot-dip coating layer, and the weight ratio of A to B satisfies 2≤B / A≤5.

5. The supercorrosion resistant coated steel sheet having excellent formability according to claim 1, characterized in that: The microstructure of the substrate is equiaxed ferrite.

6. A method of producing the ultra-high corrosion resistant coated steel sheet according to claim 1, wherein the production method comprises the steps of, in this order: The substrate is subjected to electrolytic degreasing, pickling activation, electroplating, cleaning, hot air drying, heating, hot-dip plating and cooling; characterized by that the composition of the electroplating solution in the electroplating process comprises 20-35% of 1-ethyl-3-methylimidazole chloride, 65-75% of chloroaluminate, 1-3% of aluminosilicate, 0.5-1% of benzoic acid and 1-2% of polyethylene glycol in terms of percentage by weight; the content of 1-ethyl-3-methylimidazole chloride is defined as a, the content of chloroaluminate is defined as b, and the content of aluminosilicate is defined as c, and a, b and c satisfy the relationship 1.68≤(b+c) / a≤3.

37. ​ 7. The method of claim 6, wherein: The pickling activation solution of the substrate is 10-30% of HCl solution, and the activation temperature is 40-60℃; the current density of the electroplating is 0.5-2 A / dm2, the electroplating temperature is 30-50℃, and the electroplating pH value is 3-5.

8. The method of claim 6, wherein: The cleaning is divided into three stages, the first stage is hot water flushing at 60-80℃ for 1-2 minutes, the second stage is flowing normal temperature water washing with an electric conductivity of ≤50 μS / cm, and the third stage is ultrapure water rinsing with a resistivity of 5-10 MΩ·cm, and hot air drying is adopted after cleaning.

9. The method of claim 6, wherein: The heating temperature is 380-420℃, the heating time is 1-5 min, and a hydrogen atmosphere of 5-10% is used for protection during the heating process; the hot-dip plating temperature is 400-490℃.

10. The method of claim 6, wherein: The cooling adopts a two-stage cooling process, the first-stage cooling rate is 40-50℃ / s, and the first-stage cooling end temperature is 335-350℃; the second-stage cooling rate is 1-10℃ / s, and the second-stage cooling end temperature is 200-250℃.

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