Stainless steel wire galvanizing process

Abstract

The invention belongs to the technical field of steel wire galvanizing, and particularly relates to a stainless steel wire galvanizing process. According to the method, electrogalvanizing and hot galvanizing are carried out after nickel plating, so that the problems of insufficient binding force, surface plating leakage and zinc knots in the stainless steel wire galvanizing process are effectively solved, uniform covering of a zinc layer is achieved, it is ensured that the zinc layer is free of plating leakage and zinc knots, and the zinc feeding amount reaches 300 g / m < 2 > or above; the synergistic mechanism of raw materials in the full-chain matching process of cleaning, activating, electroplating, plating assisting and hot dipping is fully utilized, the phenomena of hydrogen embrittlement and plating leakage are effectively reduced, a composite plating layer with high adhesive force, high uniformity and excellent corrosion resistance is formed, the overall performance of stainless steel wire galvanization is greatly improved, and the service life of the stainless steel wire galvanization is greatly prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of wire galvanizing, and particularly relates to a galvanizing process for stainless steel wires. Background Art

[0002] The galvanizing process for stainless steel wires is a treatment method that forms a zinc layer on the surface of stainless steel wires through electroplating or hot-dip galvanizing technology. Its main purpose is to enhance the corrosion resistance of the material, extend its service life, and improve its adaptability in specific environments by adding a layer of zinc on the surface of the stainless steel wire. As a protective layer, the galvanized layer can effectively isolate the stainless steel wire from contact with oxygen, moisture, and chemical substances in the outside world, thereby significantly improving its corrosion resistance. This process is widely used in many fields such as construction, automotive, electrical, and electronics, and is particularly important in applications where high corrosion resistance and durability are required. During the galvanizing process of stainless steel wires, two main methods, namely electroplating and hot-dip galvanizing, are usually adopted. Electroplating galvanizing is to reduce zinc ions to the surface of the stainless steel wire through an electrolytic reaction to form a uniform zinc coating; while hot-dip galvanizing is to immerse the stainless steel wire in molten zinc liquid to form a zinc alloy coating.

[0003] The key to the galvanizing process lies in how to form a zinc layer evenly and firmly on the stainless steel surface to maximize the corrosion resistance of the material and extend its service life. However, in practical applications, the galvanizing process is often affected by various factors and prone to some technical defects. First of all, the coating adhesion is one of the key factors affecting the galvanizing quality. If there is a passivation film on the stainless steel surface, insufficient pretreatment, or improper setting of galvanizing process parameters, it may lead to poor bonding between the coating and the substrate, resulting in coating peeling, which seriously affects the corrosion resistance of the product. Secondly, the phenomenon of hydrogen embrittlement is particularly worthy of attention during electrogalvanizing, especially in high-strength stainless steel wires. The infiltration of hydrogen atoms into the material will significantly reduce its mechanical properties and even pose potential safety hazards in high-demand safety applications. In addition, uneven coating thickness is also a common problem. Due to reasons such as wire pay-off vibration, uneven plating solution stirring, and irregular shape of stainless steel wires, the coating may have thickness differences. This uneven coating will cause fluctuations in corrosion resistance and affect the appearance quality. Especially in applications with high appearance requirements, it may lead to appearance defects. Finally, the surface quality of the coating cannot be ignored. Impurities in the plating solution, possible contamination during the operation process, and improper post-treatment may all have an adverse impact on the appearance and corrosion resistance of the final product. Especially in the production of special products such as submarine cables, surface defects will not only affect the appearance quality but also increase the resistance when passing through the die, and even cause the product to break. Therefore, in order to overcome the above problems, it is particularly necessary to develop a galvanizing process with high quality and excellent galvanizing adhesion. Summary of the Invention

[0004] Aiming at the defects of the prior art, the purpose of the present invention is to provide a galvanizing process for stainless steel wires.

[0005] The technical effects of the present invention are achieved through the following technical solutions: A galvanizing process for stainless steel wires, and its specific process steps are as follows: S1: Alkali washing, immersing the stainless steel wires in the alkali washing solution, maintaining the temperature at 60 - 80 °C for 5 - 60 s; S2: Water washing, after completing the alkali washing operation in step S1, continuously washing the stainless steel wires 6 times with clear water containing 1 wt% surfactant; S3: Acid pickling, after completing the water washing operation in step S2, placing the stainless steel wires in the acid pickling solution, adding 1 - 3 g / L of corrosion inhibitor, controlling the temperature at 40 - 60 °C, and soaking for 60 - 120 s; S4: Water washing, after completing the acid pickling operation in step S3, continuously washing the stainless steel wires 6 times with clear water; S5: Activation, after completing the water washing operation in step S4, immersing the stainless steel wires in the activation solution, controlling the temperature at 55 - 65 °C for 20 - 60 s; S6: Nickel electroplating, after completing the activation operation in step S5, using the stainless steel wires as the cathode and nickel plates as the anode, adopting an acidic nickel plating solution, controlling the parameters: temperature 30 - 35 °C, current density 3 - 5 A / dm 2 , and the voltage is stabilized at 6 V; S7: Zinc electroplating, after completing the nickel electroplating operation in step S6, using the stainless steel wires as the cathode and zinc plates as the anode, adopting an acidic zinc plating solution, controlling the parameters: temperature 30 °C, current density 3 - 5 A / dm 2 , and the voltage is stabilized at 6 V; S8: Water washing, after completing the zinc electroplating operation in step S7, continuously washing the stainless steel wires 6 times with clear water; S9: Fluxing, after completing the water washing operation in step S8, adding the stainless steel wires to the fluxing solution, controlling the temperature at 60 - 80 °C, and soaking for 10 - 20 s; S10: Hot dip galvanizing, after completing the fluxing operation in step S9, vertically immersing the stainless steel wires in the zinc bath, controlling the temperature at 450 - 460 °C, and soaking for 5 - 60 s; S11: Water washing, after completing the hot dip galvanizing operation in step S10, continuously washing the stainless steel wires 6 times with clear water, and after cooling, naturally air-drying to obtain galvanized stainless steel wires.

[0006] Preferably, after each operation in steps S1 - S10 is completed, nitrogen protection is connected; Preferably, in step S1, the alkali washing solution is prepared from a 1.5M NaOH solution and softened water in a volume ratio of 0.3:1.7; Preferably, in step S2, the surfactant is any one of Tween-20 and dodecyl glucoside; Preferably, in step S3, the pickling solution is prepared by mixing hydrochloric acid, citric acid and softened water in a ratio of 20 mL: 7-9 g: 80 mL; the corrosion inhibitor is 2-mercaptobenzoic acid; Preferably, in step S5, the activation solution is prepared by dissolving 3-mercaptopropyltriethoxysilane in deionized water at a concentration of 0.3-0.5 wt% and adjusting the pH to 4.5; Preferably, in step S6, the acidic nickel plating solution is composed of nickel chloride, hydrochloric acid, ammonium chloride, citric acid, ethanolamine, polyethylene glycol octyl phenyl ether and softened water; the addition amount of nickel chloride is 60-120 g / L; the addition amount of hydrochloric acid is 100-150 mL / L; the addition amount of ammonium chloride is 20-45 g / L; the addition amount of citric acid is 10-20 g / L; the addition amount of ethanolamine is 1-3 mL / L; the addition amount of polyethylene glycol octyl phenyl ether is 2-5 mL / L; Preferably, in step S7, the acidic zinc plating solution is composed of zinc sulfate, zinc chloride, aluminum sulfate, 98 wt% sulfuric acid, thiourea, ethanolamine, polyethylene glycol octyl phenyl ether and softened water; the addition amount of zinc sulfate is 160-320 g / L; the addition amount of zinc chloride is 50-120 g / L; the addition amount of aluminum sulfate is 20-30 g / L; the addition amount of 98 wt% sulfuric acid is 60-150 mL / L; the addition amount of thiourea is 1-5 g / L; the addition amount of ethanolamine is 1-3 mL / L; the addition amount of polyethylene glycol octyl phenyl ether is 2-5 mL / L; Preferably, in step S9, the specific preparation steps of the fluxing solution are as follows: A1: Add citric acid to deionized water, stir well until dissolved uniformly to obtain a citric acid solution; add 2-mercaptobenzoic acid, stir well and mix uniformly, then slowly add nano-silicate, and disperse uniformly by ultrasonic treatment to obtain a mixed solution; A2: Add silk fibroin and polyacrylamide to the mixed solution prepared in step A1 in sequence, stir well and mix uniformly, then slowly add choline chloride and ethanolamine, stir and mix uniformly, and adjust the pH to 4-5 to obtain the fluxing solution; Preferably, in step A1, the addition amount of citric acid is 40-60 g / L; the addition amount of 2-mercaptobenzoic acid is 1-2 g / L; the addition amount of nano-silicate is 2-5 g / L; Preferably, in step A2, the addition amount of silk fibroin is 0.5-1 g / L; the addition amount of polyacrylamide is 2-3 g / L; the addition amount of choline chloride is 2-5 g / L; the addition amount of ethanolamine is 2-3 mL / L; Preferably, in step S10, the composition of the zinc liquid includes raw materials in the following mass percentages: 99.5% zinc, 0.15% aluminum, 0.2% magnesium, and 0.05% calcium, and the balance is inevitable impurities.

[0007] The beneficial effects of the present invention are as follows: By electro-galvanizing and hot-dip galvanizing after nickel plating, the present invention effectively solves the problems of insufficient bonding force, surface non-plating, and zinc nodules during the galvanizing process of stainless steel wires, realizes uniform coverage of the zinc layer, ensures no non-plating and no zinc nodules on the zinc layer, and the zinc coating amount reaches 300 g / m 2Above. First, an alkaline degreasing process is used, using an alkaline washing solution prepared with NaOH solution and softened water to effectively remove grease and oxide film on the surface of the stainless steel wire to ensure surface cleanliness. Subsequently, a surfactant is added to the water washing operation to reduce the surface tension of the water, promote the efficient removal of residual NaOH and organic matter, and add nitrogen protection at the junction of each process to prevent the stainless steel wire from rapidly oxidizing in contact with the air; this series of treatments ensures that the hydrochloric acid and citric acid mixture used in the pickling process can more evenly and efficiently remove the surface oxide layer; the corrosion inhibitor 2-mercaptobenzoic acid in the pickling solution forms a stable coordination bond with the metal surface through its thiol (-SH) group to prevent further corrosion, and plays a synergistic role in promoting the subsequent activation process. In the activation process, 3-mercaptopropyltriethoxysilane (MPTMS) is used to form an organic silane layer with the steel surface, which chemically bonds to the metal surface through the thiol group, significantly enhancing the adhesion and uniformity of the nickel plating layer. In the nickel electroplating process, the acidic environment of hydrochloric acid is stably combined with the organic silane layer to ensure the uniformity and density of the coating; at the same time, the PEG octylphenyl ether and the organic components in the plating solution work together through hydrogen bonds and van der Waals forces to further improve the smoothness and density of the coating. This synergistic mechanism enables the nickel layer to be evenly distributed on the surface of the stainless steel wire, forming a smooth and dense base layer, which is beneficial to the subsequent electrogalvanizing. In the electrogalvanizing process, aluminum sulfate acts as a corrosion inhibitor to control the deposition rate of zinc, preventing excessive deposition and cracking of the coating; thiourea cooperates with organic substances such as silk fibroin and polyacrylamide through hydrogen bonds and van der Waals forces to maintain the smoothness and density of the coating. Nanosilicates, with their high surface area and catalytic activity, promote the uniform deposition of zinc ions, and work synergistically with 2-mercaptobenzoic acid to enhance the mechanical strength and wear resistance of the coating. The silk protein in the plating solution combines with the organic silane layer through hydrogen bonds and covalent bonds to form an ordered molecular layer, which further enhances the adhesion and density of the coating. At the same time, polyacrylamide and ethanolamine stabilize the pH value and corrosion inhibitor function of the plating solution through complexation, optimize the chemical environment of the plating solution, and improve the quality of the coating. The deep eutectic solvent formed by choline chloride and citric acid enhances the dispersibility and solubility of organic components through ionic bonds and hydrogen bonds, ensuring the uniformity of the coating. Finally, through the hot-dip galvanizing process, the aluminum and magnesium in the high-temperature zinc solution synergize with the corrosion inhibitor and nano-silicate in the plating solution to improve the fluidity and wettability of the zinc solution, reduce the formation of inclusions, and improve the density and uniformity of the coating. Calcium, as a trace element, acts as a deoxidizer, helping to reduce oxide inclusions in the zinc solution, ensuring the purity and stable quality of the coating. The aluminum and magnesium in the hot-dip galvanizing zinc solution form an additional protection mechanism with the corrosion inhibitor and nano-silicate in the plating solution, synergistically inhibiting the uneven corrosion of the zinc solution to the substrate or the coating, and improving the density of the coating.

[0008] In summary, through the full-chain cooperation of cleaning, activation, electroplating, fluxing, and hot-dip plating, and by utilizing the synergistic mechanism of raw materials in each process, the present invention effectively reduces hydrogen embrittlement and non-plating phenomena, forms a composite coating with high adhesion, high uniformity, and excellent corrosion resistance, and greatly improves the overall performance and service life of galvanized stainless steel wires. Brief Description of the Drawings

[0009] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0010] Figure 1 It is a graph showing the adhesion test results of the galvanized layers of stainless steel wires prepared in Example 2 and Comparative Examples 1 to 5 of the present invention; Figure 2 It is a graph showing the zinc coating amount test results of the galvanized layers of stainless steel wires prepared in Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention; Figure 3 It is a graph showing the corrosion resistance test results of the galvanized layers of stainless steel wires prepared in Example 2 and Comparative Examples 1 to 5 of the present invention; Figure 4 It is a graph showing the wear resistance test results of the galvanized layers of stainless steel wires prepared in Example 2 and Comparative Examples 1 to 5 of the present invention. Detailed Embodiments

[0011] The following will describe the technical solutions of the present invention clearly and completely in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. It should be noted that unless otherwise specified, the raw materials involved in the present invention are purchased through conventional commercial channels.

[0012] Example 1: A galvanizing process for stainless steel wires, and its specific process steps are as follows: S1: Alkaline cleaning, immersing the stainless steel wires in an alkaline cleaning solution prepared by mixing 1.5 L of 1.5 M NaOH solution and 8.5 L of softened water, maintaining the temperature at 60 °C for 60 s, and connecting nitrogen protection; S2: Water washing, after completing the alkaline cleaning operation in step S1, continuously washing the stainless steel wires 6 times with clear water containing 1 wt% Tween-20, and connecting nitrogen protection; S3: Pickling. After the water washing operation in step S2, place the stainless steel wire in the pickling solution prepared with 2 L of hydrochloric acid, 0.7 kg of citric acid, and 8 L of softened water, add 2-mercaptobenzoic acid, control the temperature at 40 °C, soak for 120 s, and connect to nitrogen protection; S4: Water washing. After the pickling operation in step S3, continuously wash the stainless steel wire with clean water 6 times, and connect to nitrogen protection; S5: Activation. After the water washing operation in step S4, immerse the stainless steel wire in 10 L of 3-mercaptopropyltriethoxysilane activation solution with a pH of 4.5 and a concentration of 0.3 wt%, control the temperature at 55 °C, and the time at 60 s, and connect to nitrogen protection; S6: Nickel electroplating. After the activation operation in step S5, use the stainless steel wire as the cathode and the nickel plate as the anode, adopt an acidic nickel plating solution, control the parameters: temperature 30 °C, current density 3 A / dm 2 , the voltage is stable at 6 V, and connect to nitrogen protection; The acidic nickel plating solution is composed of 1.5 kg of nickel chloride, 2.5 L of hydrochloric acid, 0.5 kg of ammonium chloride, 0.25 kg of citric acid, 0.025 L of ethanolamine, 0.05 L of polyethylene glycol octyl phenyl ether, and 25 L of softened water; S7: Zinc electroplating. After the nickel electroplating operation in step S6, use the stainless steel wire as the cathode and the zinc plate as the anode, adopt an acidic zinc plating solution, control the parameters: temperature 30 °C, current density 3 A / dm 2 , the voltage is stable at 6 V, and connect to nitrogen protection; The acidic zinc plating solution is composed of 9.6 kg of zinc sulfate, 3 kg of zinc chloride, 1.2 kg of aluminum sulfate, 3.6 L of 98 wt% sulfuric acid, 0.06 kg of thiourea, 0.06 L of ethanolamine, 0.12 L of polyethylene glycol octyl phenyl ether, and 60 L of softened water; S8: Water washing. After the zinc electroplating operation in step S7, continuously wash the stainless steel wire with clean water 6 times, and connect to nitrogen protection; The specific preparation steps of the fluxing agent are as follows: A1: Add 0.8 kg of citric acid to 20 L of deionized water, stir well until dissolved evenly to obtain a citric acid solution; add 0.02 kg of 2-mercaptobenzoic acid, stir well and mix evenly, then slowly add 0.04 kg of nano-silicate, and disperse evenly by ultrasonic treatment to obtain a mixed solution; A2: Add 0.01 kg of silk fibroin and 0.04 kg of polyacrylamide to the mixed solution prepared in step A1 in sequence, stir well and mix evenly, then slowly add 0.04 kg of choline chloride and 0.04 L of ethanolamine, stir and mix evenly, and adjust the pH to 4 to obtain the fluxing agent; S9: Fluxing. After completing the water washing operation in step S8, add the stainless steel wire to 20 L of fluxing solution, control the temperature at 60 °C, soak for 20 s, and then connect to nitrogen protection; S10: Hot-dip galvanizing. After completing the fluxing operation in step S9, vertically immerse the stainless steel wire into 10 kg of zinc solution composed of 99.5% zinc, 0.15% aluminum, 0.2% magnesium, and 0.05% calcium, control the temperature at 450 °C, soak for 60 s, and then connect to nitrogen protection; S11: Water washing. After completing the hot-dip galvanizing operation in step S10, continuously wash the stainless steel wire with clear water 6 times, and after cooling, let it air dry naturally to obtain galvanized stainless steel wire.

[0013] Example 2: A galvanizing process for stainless steel wire, and its specific process steps are as follows: S1: Alkaline washing. Immerse the stainless steel wire into the alkaline washing solution prepared by mixing 1.5 L of 1.5 M NaOH solution and 8.5 L of softened water, keep the temperature at 70 °C, for 20 s, and then connect to nitrogen protection; S2: Water washing. After completing the alkaline washing operation in step S1, continuously wash the stainless steel wire with clear water containing 1 wt% dodecyl glucoside 6 times, and then connect to nitrogen protection; S3: Acid washing. After completing the water washing operation in step S2, place the stainless steel wire in the acid washing solution prepared by mixing 2 L of hydrochloric acid, 0.8 kg of citric acid, and 8 L of softened water, add 2-mercaptobenzoic acid, control the temperature at 50 °C, soak for 90 s, and then connect to nitrogen protection; S4: Water washing. After completing the acid washing operation in step S3, continuously wash the stainless steel wire with clear water 6 times, and then connect to nitrogen protection; S5: Activation. After completing the water washing operation in step S4, immerse the stainless steel wire into 10 L of 3-mercaptopropyltriethoxysilane activation solution with a pH of 4.5 and a concentration of 0.4 wt%, control the temperature at 60 °C, for 35 s, and then connect to nitrogen protection; S6: Nickel electroplating. After completing the activation operation in step S5, use the stainless steel wire as the cathode and the nickel plate as the anode, adopt an acidic nickel plating solution, control the parameters at a temperature of 32 °C and a current density of 5 A / dm 2 , with a stable voltage of 6 V, and then connect to nitrogen protection; The acidic nickel plating solution is composed of 2.25 kg of nickel chloride, 3 L of hydrochloric acid, 0.875 kg of ammonium chloride, 0.375 kg of citric acid, 0.05 L of ethanolamine, 0.1 L of polyethylene glycol octyl phenyl ether, and 25 L of softened water; S7: Zinc electroplating. After completing the nickel electroplating operation in step S6, use the stainless steel wire as the cathode and the zinc plate as the anode, adopt an acidic zinc plating solution, control the parameters at a temperature of 30 °C and a current density of 5 A / dm 2 , with a stable voltage of 6 V, and then connect to nitrogen protection; The acid zinc plating solution is composed of 16.8 kg of zinc sulfate, 5.4 kg of zinc chloride, 1.5 kg of aluminum sulfate, 7.2 L of 98 wt% sulfuric acid, 0.18 kg of thiourea, 0.12 L of ethanolamine, 0.18 L of polyethylene glycol octyl phenyl ether, and 60 L of softened water; S8: Water washing. After the electro-galvanizing operation in step S7 is completed, the stainless steel wire is continuously washed with clear water 6 times, and then nitrogen protection is connected; The specific preparation steps of the fluxing solution are as follows: A1: Add 1 kg of citric acid to 20 L of deionized water, stir well until dissolved evenly to obtain a citric acid solution; add 0.03 kg of 2-mercaptobenzoic acid, stir well and mix evenly, then slowly add 0.08 kg of nano-silicate, and disperse evenly by ultrasonic treatment to obtain a mixed solution; A2: Add 0.016 kg of silk fibroin and 0.05 kg of polyacrylamide to the mixed solution prepared in step A1 in sequence, stir well and mix evenly, then slowly add 0.08 kg of choline chloride and 0.05 L of ethanolamine, stir and mix evenly, and adjust the pH to 4.5 to obtain the fluxing solution; S9: Fluxing. After the water washing operation in step S8 is completed, add the stainless steel wire to 20 L of the fluxing solution, control the temperature at 70 °C, soak for 15 s, and then connect nitrogen protection; S10: Hot-dip galvanizing. After the fluxing operation in step S9 is completed, vertically immerse the stainless steel wire into 10 kg of zinc solution composed of 99.5% zinc, 0.15% aluminum, 0.2% magnesium, and 0.05% calcium, control the temperature at 455 °C, soak for 25 s, and then connect nitrogen protection; S11: Water washing. After the hot-dip galvanizing operation in step S10 is completed, continuously wash the stainless steel wire with clear water 6 times, cool it, and then air-dry it naturally to obtain the galvanized stainless steel wire.

[0014] Example 3: A galvanizing process for stainless steel wire, and its specific process steps are as follows: S1: Alkaline washing. Immerse the stainless steel wire into the alkaline washing solution prepared by mixing 1.5 L of 1.5 M NaOH solution and 8.5 L of softened water, keep the temperature at 80 °C, for 5 s, and then connect nitrogen protection; S2: Water washing. After the alkaline washing operation in step S1 is completed, continuously wash the stainless steel wire with clear water containing 1 wt% Tween-20 6 times, and then connect nitrogen protection; S3: Acid washing. After the water washing operation in step S2 is completed, place the stainless steel wire in the acid washing solution prepared by 2 L of hydrochloric acid, 0.9 kg of citric acid, and 8 L of softened water, add 2-mercaptobenzoic acid, control the temperature at 60 °C, soak for 60 s, and then connect nitrogen protection; S4: Water washing. After the acid washing operation in step S3 is completed, continuously wash the stainless steel wire with clear water 6 times, and then connect nitrogen protection; S5: Activation. After completing the water washing operation in step S4, immerse the stainless steel wire in 10 L of an activation solution of 3-mercaptopropyltriethoxysilane with a pH of 4.5 and a concentration of 0.5 wt%, control the temperature at 65 °C, for a time of 20 s, and connect to nitrogen protection; S6: Nickel plating. After completing the activation operation in step S5, use the stainless steel wire as the cathode and a nickel plate as the anode, and adopt an acidic nickel plating solution. Control the parameters: temperature 35 °C, current density 4 A / dm 2 , voltage stabilized at 6 V, and connect to nitrogen protection; The acidic nickel plating solution is composed of 3 kg of nickel chloride, 3.75 L of hydrochloric acid, 1.125 kg of ammonium chloride, 0.5 kg of citric acid, 0.075 L of ethanolamine, 0.125 L of polyethylene glycol octyl phenyl ether, and 25 L of softened water; S7: Zinc plating. After completing the nickel plating operation in step S6, use the stainless steel wire as the cathode and a zinc plate as the anode, and adopt an acidic zinc plating solution. Control the parameters: temperature 30 °C, current density 4 A / dm 2 , voltage stabilized at 6 V, and connect to nitrogen protection; The acidic zinc plating solution is composed of 19.2 kg of zinc sulfate, 7.2 kg of zinc chloride, 1.8 kg of aluminum sulfate, 9 L of 98 wt% sulfuric acid, 0.3 kg of thiourea, 0.18 L of ethanolamine, 0.3 L of polyethylene glycol octyl phenyl ether, and 60 L of softened water; S8: Water washing. After completing the zinc plating operation in step S7, continuously wash the stainless steel wire with clean water 6 times, and connect to nitrogen protection; The specific preparation steps of the fluxing solution are as follows: A1: Add 1.2 kg of citric acid to 20 L of deionized water, stir well until dissolved evenly to obtain a citric acid solution; add 0.04 kg of 2-mercaptobenzoic acid, stir well and mix evenly, then slowly add 0.1 kg of nano-silicate, and disperse evenly by ultrasonic treatment to obtain a mixed solution; A2: Add 0.02 kg of silk fibroin and 0.06 kg of polyacrylamide to the mixed solution prepared in step A1 in sequence, stir well and mix evenly, then slowly add 0.1 kg of choline chloride and 0.06 L of ethanolamine, stir and mix evenly, and adjust the pH to 5 to obtain the fluxing solution; S9: Fluxing. After completing the water washing operation in step S8, add the stainless steel wire to 20 L of the fluxing solution, control the temperature at 80 °C, soak for 10 s, and connect to nitrogen protection; S10: Hot-dip galvanizing. After completing the fluxing operation in step S9, vertically immerse the stainless steel wire in 10 kg of a zinc bath composed of 99.5% zinc, 0.15% aluminum, 0.2% magnesium, and 0.05% calcium, control the temperature at 460 °C, soak for 5 s, and connect to nitrogen protection; S11: Water washing. After the hot-dip galvanizing operation in step S10 is completed, the stainless steel wire is continuously washed with clear water 6 times, and then naturally air-dried after cooling to obtain galvanized stainless steel wire.

[0015] Comparative Example 1: The operation of Comparative Example 1 is basically the same as that of Example 2, except that the activation step in step S5 is omitted in Comparative Example 1.

[0016] Comparative Example 2: The operation of Comparative Example 2 is basically the same as that of Example 2, except that the nickel plating step in step S6 is omitted in Comparative Example 2.

[0017] Comparative Example 3: The operation of Comparative Example 3 is basically the same as that of Example 2, except that the fluxing step in step S9 is omitted in Comparative Example 3.

[0018] Comparative Example 4: The operation of Comparative Example 4 is basically the same as that of Example 2, except that sulfuric acid is used to replace 3-mercaptopropyltriethoxysilane for activation in Comparative Example 4.

[0019] Comparative Example 5: The operation of Comparative Example 5 is basically the same as that of Example 2, except that nano-silicate is not added in Comparative Example 5.

[0020] Performance test: Adhesion test: The galvanized stainless steel wire samples prepared in Example 2 and Comparative Examples 1-5 are gradually pulled with a universal material testing machine at a constant rate (10 mm / min) to test the adhesion (N / mm 2 ) when the coating starts to peel off. The results are as Figure 1 shown.

[0021] From Figure 1It can be seen from the results that the galvanizing process of the present invention significantly improves the adhesion of the galvanized layer through the synergistic effect of multiple steps and raw material preparations, and has excellent performance; it can be seen from the results of Comparative Example 1 and Example 2 that the formation of the silane layer without the activation step significantly affects the chemical bonding effect with the substrate surface, and there is a lack of effective chemical bonding between the coating and the substrate, resulting in a significant decrease in adhesion; it can be seen from the results of Comparative Example 2 and Example 2 that without the support of the compactness and adhesion of the nickel layer, the absence of the nickel layer may lead to uneven deposition of the zinc layer, resulting in a significant impact on the bonding strength between the zinc layer and the substrate; it can be seen from the results of Comparative Example 3 and Example 2 that additives such as nano-silicate, silk fibroin, and polyacrylamide in the flux promote the uniform deposition of zinc ions and the compactness of the coating through synergistic effects. The absence leads to roughness and local peeling of the coating, resulting in a significant reduction in adhesion; it can be seen from the results of Comparative Example 4 and Example 2 that using sulfuric acid to replace MPTMS for activation results in a decrease in chemical bonding force and a certain degree of influence on adhesion; it can be seen from the results of Comparative Example 5 and Example 2 that nano-silicate promotes the uniform deposition of zinc ions through its high surface area and catalytic activity, and synergistically enhances the mechanical strength and compactness of the coating with 2-mercaptobenzoic acid. The absence of nano-silicate results in a decrease in the compactness and uniformity of the coating, thereby affecting the adhesion.

[0022] Zinc coating amount test: Stainless steel wires of the same length as those in Examples 1-3 and Comparative Examples 1-5 were weighed for the initial weight, and then the final weights of the galvanized stainless steel wire samples after drying in Examples 1-3 and Comparative Examples 1-5 were weighed. The zinc coating amount (g / m 2 ) = (final weight - initial weight) / coating area, and the results are as Figure 2 shown.

[0023] From Figure 2 the results, it can be seen that the galvanizing process of the present invention has an excellent galvanizing effect, and the zinc coating amount effectively reaches 300 g / m 2As above; from the results of Comparative Example 1 and Example 2, it can be seen that the absence of the activation step leads to a decrease in the adhesion between the coating and the substrate, which may significantly affect the deposition efficiency and uniformity of the subsequent galvanized coating; from the results of Comparative Example 2 and Example 2, it can be seen that the absence of the nickel layer results in insufficient bonding force between the galvanized coating and the substrate, which may limit the thickness and uniformity of the coating, and thus lead to a significant decrease in the zinc coating amount; from the results of Comparative Example 3 and Example 2, it can be seen that the flux plays a role in improving the fluidity of the plating solution and promoting the uniform deposition of the coating during electroplating. The absence of the fluxing step significantly reduces the coating deposition efficiency and significantly affects the coating thickness; from the results of Comparative Example 4 and Example 2, it can be seen that using sulfuric acid as an activator leads to a decrease in the adhesion between the coating and the substrate, and the synergistic effect with the preparations in the subsequent steps is affected, and the zinc coating amount is affected to a certain extent; from the results of Comparative Example 5 and Example 2, it can be seen that the absence of nano-silicate significantly affects the synergistic effect with other additives, and the coating deposition efficiency and uniformity decrease.

[0024] Corrosion resistance test: The galvanized stainless steel wire samples prepared in Example 2 and Comparative Examples 1-5 were tested using a 5% concentration of NaCl solution at an air flow rate of 3 m / s. The temperature was set at 37 °C and the humidity was 95%. On the 7th day, the mass loss was measured as (weight before test - weight after test) / weight before test × 100%. The results are as Figure 3 shown, and the appearance changes of the samples were recorded on the 1st, 3rd, 5th, and 7th days. The results are shown in Table 1 below.

[0025] Table 1. Corrosion resistance test results of galvanized stainless steel wire

[0026] From Table 1 and Figure 3As can be seen from the results, through the synergistic effect of multiple steps, the present invention effectively achieves high density and uniformity of the coating, and the galvanized coating exhibits excellent corrosion resistance. From the results of Comparative Example 1 and Example 2, it can be seen that the lack of the organosilane layer weakens the chemical bonding force between the coating and the substrate, making it easier for the zinc layer to form micropores and cracks, increasing the corrosion channels, weakening the protective effect of the zinc layer, and resulting in an increase in mass loss. From the results of Comparative Example 2 and Example 2, it can be seen that the lack of the nickel layer causes the zinc layer to be directly deposited on the substrate, resulting in a significant decrease in adhesion and density, uneven deposition of the zinc layer, weakening of the overall protective ability of the zinc layer, and obvious mass loss. From the results of Comparative Example 3 and Example 2, it can be seen that the lack of the flux leads to a decrease in fluidity and uniformity during the deposition of the zinc layer, forming a zinc layer with roughness and more pores, thereby significantly affecting the corrosion resistance of the zinc layer. From the results of Comparative Example 4 and Example 2, it can be seen that the substitution effect of sulfuric acid is extremely poor, significantly decreasing the chemical bonding force between the zinc layer and the substrate, significantly affecting adhesion and density, and significantly affecting the corrosion resistance of the zinc layer. From the results of Comparative Example 5 and Example 2, it can be seen that the lack of nano-silicate results in a decrease in uniformity and density during the deposition of the zinc layer, forming more micropores and rough areas, which may lead to a significant impact on corrosion resistance.

[0027] Wear resistance test: Fix the galvanized stainless steel wires prepared in Example 2 and Comparative Examples 1-5 to the test equipment, set the load at 100 N, the rotation speed at 60 rpm, and the time at 60 min. Measure the mass change before and after the test, and calculate the wear loss / (%) = (mass before test - mass after test) / mass before test × 100%. The results are as Figure 4 shown.

[0028] From Figure 4 the results, it can be seen that through the synergistic effect of multiple steps and raw materials, the present invention achieves high density, uniformity, and good adhesion of the coating, significantly improving the wear resistance of the coating. From the results of Comparative Example 4 and Example 2, it can be seen that the replacement treatment of sulfuric acid may lead to the formation of softer and more easily worn areas on the coating surface, significantly affecting the wear resistance. From the results of Comparative Example 1 and Example 2, it can be seen that the absence of the activation step completely lacks the formation of an organic layer, significantly decreasing the physical and chemical bonding forces between the coating and the substrate. The decrease in coating density may cause a uniform wear layer to form relatively quickly on the coating during wear, thereby resulting in an insignificant impact on its wear resistance.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A stainless steel wire galvanizing process, characterized in that: The specific process steps are as follows: S1: Alkaline washing, immersing the stainless steel wire in the alkaline washing solution; S2: washing with water, after completing the alkaline washing operation in step S1, the stainless steel wire is continuously washed with clean water containing a surfactant; S3: pickling, after completing the water washing operation in step S2, placing the stainless steel wire in a pickling solution; S4: washing with water, after completing the pickling operation in step S3, the stainless steel wire is continuously washed with clean water; S5: Activation, after completing the water washing operation in step S4, immersing the stainless steel wire in an activation solution; S6: electroplating nickel, after completing the activation operation in step S5, the stainless steel wire is used as the cathode and the nickel plate is used as the anode, and an acidic nickel plating solution is used; S7: electrogalvanizing, after completing the nickel electroplating operation in step S6, the stainless steel wire is used as the cathode and the zinc plate is used as the anode, and an acidic zinc plating solution is used; S8: Washing with water, after the electrogalvanizing operation in step S7 is completed, the stainless steel wire is continuously washed with clean water; S9: Plating aid, after completing the water washing operation in step S8, adding the stainless steel wire into the plating aid solution; S10: hot-dip galvanizing, after completing the assisting plating operation in step S9, immerse the stainless steel wire vertically in the zinc solution; S11: washing with water. After the hot-dip galvanizing operation in step S10 is completed, the stainless steel wire is continuously washed with clean water, cooled and naturally air-dried to obtain galvanized stainless steel wire.

2. A stainless steel wire galvanizing process according to claim 1, characterized in that: In step S1, the alkaline washing solution is prepared by mixing 1.5M NaOH solution and softened water in a volume ratio of 0.3:1.

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3. A stainless steel wire galvanizing process according to claim 2, characterized in that: In step S2, the surfactant is any one of Tween-20 and dodecyl glucoside.

4. A stainless steel wire galvanizing process according to claim 3, characterized in that: In step S3, the pickling solution is prepared by preparing hydrochloric acid, citric acid and softened water in a ratio of 20 mL: 7-9 g: 80 mL; and the corrosion inhibitor is 2-mercaptobenzoic acid.

5. A stainless steel wire galvanizing process according to claim 4, characterized in that: In step S5, the activation solution is prepared by dissolving 3-mercaptopropyltriethoxysilane in deionized water at a concentration of 0.3-0.5 wt % and adjusting the pH to 4.

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6. A stainless steel wire galvanizing process according to claim 5, characterized in that: In step S6, the acidic nickel plating solution is composed of nickel chloride, hydrochloric acid, ammonium chloride, citric acid, ethanolamine, polyethylene glycol octyl phenyl ether and softened water; the amount of nickel chloride added is 60-120 g / L; the amount of hydrochloric acid added is 100-150 mL / L; the amount of ammonium chloride added is 20-45 g / L; the amount of citric acid added is 10-20 g / L; the amount of ethanolamine added is 1-3 mL / L; the amount of polyethylene glycol octyl phenyl ether added is 2-5 mL / L.

7. A stainless steel wire galvanizing process according to claim 6, characterized in that: In step S7, the acid zinc plating solution is composed of zinc sulfate, zinc chloride, aluminum sulfate, 98wt% sulfuric acid, thiourea, ethanolamine, polyethylene glycol octyl phenyl ether and softened water; the amount of zinc sulfate added is 160-320g / L; the amount of zinc chloride added is 50-120g / L; the amount of aluminum sulfate added is 20-30g / L; the amount of 98wt% sulfuric acid added is 60-150mL / L; the amount of thiourea added is 1-5g / L; the amount of ethanolamine added is 1-3mL / L; the amount of polyethylene glycol octyl phenyl ether added is 2-5mL / L.

8. A stainless steel wire galvanizing process according to claim 7, characterized in that: In step S9, the specific preparation steps of the plating solution are as follows: A1: Add citric acid to deionized water, stir thoroughly to dissolve evenly, and obtain a citric acid solution; add 2-mercaptobenzoic acid, stir thoroughly to mix evenly, and then slowly add nano-silicate, and perform ultrasonic treatment to disperse evenly, and obtain a mixed solution; A2: Add silk fibroin and polyacrylamide to the mixed solution prepared in step A1 in sequence, stir and mix thoroughly, then slowly add choline chloride and ethanolamine, stir and mix evenly, adjust the pH to 4-5, and obtain a plating solution.

9. A stainless steel wire galvanizing process according to claim 8, characterized in that: In step A1, the amount of citric acid added is 40-60 g / L; the amount of 2-mercaptobenzoic acid added is 1-2 g / L; the amount of nanosilicate added is 2-5 g / L; in step A2, the amount of silk fibroin added is 0.5-1 g / L; the amount of polyacrylamide added is 2-3 g / L; the amount of choline chloride added is 2-5 g / L; and the amount of ethanolamine added is 2-3 mL / L.

10. A stainless steel wire galvanizing process according to claim 9, characterized in that: In step S10, the zinc solution comprises the following raw materials in percentage by mass: 99.5% zinc, 0.15% aluminum, 0.2% magnesium and 0.05% calcium.

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