High-uniformity hot-dip galvanizing process

Abstract

The invention relates to the technical field of galvanizing, and discloses a high-uniformity hot-dip galvanizing process which comprises the following steps: S1, soaking a workpiece I and a workpiece II in an acid solution; s2, the first workpiece and the second workpiece are washed with water, and the workpieces are washed with clear water; s3, the first workpiece and the second workpiece are immersed in a plating assistant; s4, the first workpiece and the second workpiece are immersed in molten zinc liquid; s5, the first workpiece and the second workpiece are cooled, and after the zinc liquid layers on the surfaces of the first workpiece and the second workpiece are solidified, the galvanized first workpiece and the galvanized second workpiece are checked, trimmed and passivated; s6, asbestos cloth is placed in clean water used for cleaning the first workpiece and the second workpiece, the surface of the asbestos cloth is kept wet, the other surfaces, except for the welding position, of the first workpiece and the second workpiece are covered with the asbestos cloth, the first workpiece and the second workpiece are welded, in the welding process, clean water is continuously poured into the asbestos cloth, and after the humidity of the asbestos cloth is guaranteed, the asbestos cloth is welded; and the spliced galvanized part is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of galvanizing, in particular to a high-uniformity hot-dip galvanizing process. BACKGROUND

[0002] Hot-dip galvanizing is the most effective industrial means of corrosion protection for steel materials and components. The traditional hot-dip galvanizing process has high energy consumption, poor thickness uniformity of the galvanized layer, easy corrosion, and poor wear resistance.

[0003] Chinese patent publication No. CN103334073A discloses a hot-dip galvanizing process, comprising the following steps: 1) oil removal; 2) pickling; 3) immersion activation; 4) drying and preheating; 5) hot-dip galvanizing; 6) cooling and drying; and 7) inspection. The process has low energy consumption, uniform thickness of the galvanized layer, improved corrosion resistance and wear resistance of the galvanized layer, and reduced production cost of the enterprise.

[0004] During the conception process, the applicant searched a large number of patent documents on the patent network, such as Chinese patent publication No. CN103334073A, which discloses a hot-dip galvanizing process. However, when the galvanized part is welded, the sparks and high temperature generated during welding can easily damage the galvanized layer on the surface of the galvanized part, and the galvanized layer at the welded part can be completely damaged. Re-galvanizing requires removing the original galvanized layer, and the environment required for galvanizing the galvanized part after welding is relatively harsh. Re-galvanizing after welding will increase the cost in a straight line. Therefore, a high-uniformity hot-dip galvanizing process is proposed to solve the above problems. SUMMARY

[0005] (I) Technical problems solved In view of the deficiencies of the prior art, the present application provides a high-uniformity hot-dip galvanizing process, which solves the problem that the galvanized layer of a large-sized galvanized part is severely damaged during welding, which seriously affects the use of the galvanized part.

[0006] (II) Technical solutions To achieve the above object, the present application provides the following technical solutions: a high-uniformity hot-dip galvanizing process, S1, immersing workpiece one and workpiece two in an acid solution; S2, water washing workpiece one and workpiece two, and rinsing the workpieces with clean water; S3, immersing workpiece one and workpiece two in a plating aid; S4, immersing workpiece one and workpiece two in molten zinc liquid; S5, cooling workpiece one and workpiece two, and after the zinc liquid layer on the surface of workpiece one and workpiece two solidifies, inspecting, trimming and passivating the galvanized workpieces; S6, placing asbestos cloth in the clean water used to clean workpiece one and workpiece two, keeping the asbestos cloth surface wet, covering the surfaces of workpiece one and workpiece two except the welding part with the asbestos cloth, and welding workpiece one and workpiece two, continuously pouring clean water on the asbestos cloth during the welding process, and ensuring the humidity of the asbestos cloth, to obtain a spliced galvanized part; and S7, repeatedly brushing cold galvanizing liquid on the welding part of the spliced galvanized part, cooling the spliced galvanized part, and then re-inspecting, trimming and passivating the spliced galvanized part.

[0007] Preferably, the acid solution in S1 is a sulfuric acid solution, the temperature is 40 DEG C, the concentration is between 5% and 20%, and the acid solution also contains inhibitors, corrosion inhibitors and the like, and the immersion time in the sulfuric acid solution is between 60 min and 30 min.

[0008] Preferably, after the workpiece one and workpiece two are preliminarily cleaned by adding an appropriate amount of dishwashing liquid to the clean water in S2, the workpiece one and workpiece two are immersed in soapy water, circularly rubbed with a sponge, and then immersed in clean water for 10 min to 20 min, and after the immersion ends, the workpiece one and workpiece two are subjected to dehumidification treatment by using a fan.

[0009] Preferably, the components of the plating aid in S3 include complexing agents, brighteners, leveling agents, pinhole removers, dispersants, wetting agents and smoke suppressants.

[0010] Preferably, before being immersed in the molten zinc liquid in S5, the workpiece one and workpiece two are immersed in an activator to further clean the metal surface to form an oxide layer, and then subjected to water washing and drying treatment again before being immersed in the molten zinc liquid for galvanizing treatment.

[0011] Preferably, the material of the asbestos cloth in S6 is dust-free asbestos cloth or dust-containing asbestos cloth, the asbestos cloth is single-layer asbestos cloth with a thickness of 0.8 mm, and the asbestos cloth can be subjected to various processing such as cutting, rubber coating and edge folding according to needs. Meanwhile, the asbestos cloth can be customized according to different requirements, such as special size and special shape. Since the asbestos cloth generates asbestos dust at high temperature, but the dust can be effectively suppressed by wetting the asbestos cloth with clean water, and the wetted asbestos cloth can better protect the workpiece one and workpiece two, so that the galvanized layer of the workpiece one and workpiece two can be greatly protected during welding.

[0012] Preferably, the welding process in S6 is to weld workpiece one and workpiece two by automatic solid-state laser welding, and a flux is added during the welding process, the main components of the flux being a mixture of rosin, resin and halogen compounds, and the welding method in S6 can also be welding of a galvanized part, which mainly includes gas welding, electric arc welding, MIG welding and TIG welding. These methods have advantages and disadvantages and are suitable for different welding requirements and material types.

[0013] Preferably, after the spliced galvanized part is welded, the welding site is polished by a polisher, and after polishing, the surface welding slag and spatter of the spliced galvanized part are wiped by asbestos cloth and then cooled.

[0014] Preferably, the inspection of the spliced galvanized part in S7 includes appearance quality, thickness, roughness, adhesion and chemical composition, and the modification treatment of the spliced galvanized part includes surface pretreatment, repair and post-treatment, and the passivation treatment is mainly to spray a passivation agent on the surface of the spliced galvanized part.

[0015] (Three) beneficial effects Compared with the prior art, the present application provides a high-uniformity hot-dip galvanizing process, which has the following beneficial effects: 1. The high-uniformity hot-dip galvanizing process uses the setting of asbestos cloth to cover the non-welding sites of workpiece one and workpiece two during welding, effectively preventing welding sparks from damaging the galvanizing layer, and the wet asbestos cloth has strong high-temperature resistance, so that the galvanizing layer on the spliced galvanized part can be more completely protected.

[0016] 2. The high-uniformity hot-dip galvanizing process uses repeated brushing of cold galvanizing liquid on the welding site of the spliced galvanized part to completely repair the damaged galvanizing layer, and through repeated brushing of the cold galvanizing liquid, the thickness of the cold galvanizing hot-dip galvanizing galvanizing layer is the same, achieving the same function as the hot-dip galvanizing galvanizing layer, so that the service life of the spliced galvanized part is improved.

[0017] 3. The high-uniformity hot-dip galvanizing process uses the galvanized part to comprehensively inspect the appearance quality, thickness, roughness, adhesion and chemical composition of the galvanized part after welding, effectively improving the quality of the galvanized part and ensuring that the service life of the galvanized part is improved. DETAILED DESCRIPTION

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] A high-uniformity hot-dip galvanizing process includes the following steps: S1. Immersing workpiece 1 and workpiece 2 in an acid solution. The acid solution in S1 is a sulfuric acid solution at a temperature of 40℃ and a concentration between 5% and 20%. The acid solution also contains inhibitors and corrosion inhibitors. The immersion time is between 30 and 60 minutes. S2. Washing workpiece 1 and workpiece 2 with clean water. In S2, after preliminary cleaning of workpiece 1 and workpiece 2 with a suitable amount of detergent, workpiece 1 and workpiece 2 are immersed in clean water for 10 to 20 minutes after being soaked in soapy water and vigorously rubbed in a circular motion. Use a fan to dehumidify workpieces one and two. During the cleaning process, avoid using corrosive chemicals as much as possible, as they may damage the surface of the galvanized parts. S3. Immerse workpieces one and two in a fluxing agent. The fluxing agent in S3 includes a complexing agent (complexing agents, especially organic complexing agents with multifunctional groups, are increasingly used in the printing and dyeing industry, such as softening water, preventing sediment, eliminating scale buildup in dyeing and finishing equipment, preventing bleaching holes in fabrics, and ensuring color vibrancy), and a brightener (whose main function is to remove oil, oxidized and unoxidized surface impurities remaining on the metal surface through active surfaces, maintaining the cleanliness, gloss, and color fastness of the object). The grinding process affects the texture of the appearance and improves polishing efficiency. Other agents include leveling agents, pinhole removers, dispersants (dispersants are surfactants with both lipophilic and hydrophilic properties within their molecules; they can uniformly disperse solid and liquid particles of inorganic and organic pigments that are difficult to dissolve in liquids, while also preventing particle sedimentation and aggregation, forming a stable suspension), and wetting agents (whose main function is to reduce the surface tension or interfacial tension of water, allowing solid surfaces to be wetted by water; they can make water-insoluble pesticides into suspensions after dilution, and can also wet and spread the pesticide solution on the surface of crops, insects, and pathogens, thereby improving...). High control effect, reducing the occurrence of pesticide damage. Commonly used wetting agents include tea seed cake, laundry detergent, and slagging powder, as well as smoke inhibitors (smoke inhibitors are powdered solids used to inhibit the volatilization of hydrochloric acid mist, while promoting the removal of various oil stains during the hydrochloric acid pickling process, slowing down or inhibiting the corrosion of metals by hydrochloric acid, and having a good synergistic effect with hydrochloric acid, suitable for hydrochloric acid use at various temperatures); S4, immerse workpiece one and workpiece two in molten zinc liquid, the entire surface of workpiece one and workpiece two is protected, whether in the recessed parts of the pipe fittings, or any corners that are difficult for other coatings to penetrate, molten zinc can easily and evenly cover them, and the hardness value of the zinc coating is greater than that of steel.The top Etalayer has a hardness of only 70 DPN, making it susceptible to dents from impacts. However, the lower Zetalayer and Deltalayer have DPN hardness values ​​of 179 and 211 respectively, higher than the 159D value of iron, resulting in excellent impact and abrasion resistance. In corner areas, the zinc layer is often thicker than elsewhere, exhibiting good toughness and abrasion resistance. Other coatings in these corner areas are often the thinnest, most difficult to apply, and most vulnerable, requiring frequent maintenance. Even if a small portion of the zinc layer peels off due to significant mechanical damage or other reasons, exposing the iron base, the surrounding zinc layer acts as a sacrificial anode, protecting the steel from corrosion. Conversely, other coatings will rust immediately and rapidly spread beneath, causing peeling. Zinc layer degradation in the atmosphere is very slow, approximately 1 / 17 to 1 / 18 of the corrosion rate of steel, and is predictable. Its lifespan far exceeds that of any other coating. During the zinc immersion process, the temperature should be controlled at 21~24℃ to ensure a uniform and fine zinc layer. The immersion time is generally 20~120 seconds; too long or too short a time will affect the coating quality. For every 0.01 unit increase in specific gravity, 20 ml / L of cyanide-free zinc immersion solution for aluminum needs to be added. Every 22 ml / L added provides 1 g / L of zinc content. At the same time, as needed, use a pipette to accurately draw up the working solution and add appropriate amounts of pure water, buffer solution, and anhydrous ethanol, etc.; S5, cool workpiece one and workpiece two, and wait for the zinc liquid layer on the surface of workpiece one and workpiece two to solidify. After the zinc plating, inspect, repair, and passivate workpiece one and workpiece two. In S5, before immersing in the molten zinc liquid, soak workpiece one and workpiece two in an activator (an activator is a type of modifier in flotation reagents that can enhance the adsorption capacity of mineral surfaces for collectors). The process involves altering the chemical composition of the mineral surface, eliminating inhibitory effects, and enhancing the mineral surface's ability to adsorb collectors. This process further cleans the metal surface, forming an oxide layer. After washing and drying, the metal is immersed in molten zinc for galvanizing. S6: Asbestos cloth is placed in clean water used to clean workpieces one and two, keeping the surface moist. The surfaces of workpieces one and two, except for the welding area, are covered with asbestos cloth. Workpieces one and two are then welded. During welding, clean water is continuously poured onto the asbestos cloth to maintain its moisture level, resulting in a spliced ​​galvanized part. The asbestos cloth in S6 is either dust-free or dusty. A single-layer asbestos cloth is used (asbestos cloth can be processed as needed, such as cutting, coating, and folding).Meanwhile, customization is also available according to different requirements, such as special sizes and shapes. Asbestos cloth produces asbestos dust at high temperatures, but this can be effectively controlled by humidifying it with water. The humidified asbestos cloth also better protects workpieces one and two, ensuring excellent protection of their galvanized layers during welding. The thickness is 0.8mm. In S6, welding is performed using automatic solid-state laser welding to connect workpieces one and two. Flux is added during the welding process; its main components are a mixture of rosin, resin, and halogen compounds. A flux is a chemical auxiliary agent used in electroplating to improve the quality and appearance of the electroplated layer, increase electroplating efficiency, and reduce electroplating costs. Electroplating additives regulate the physical and chemical reactions during the electroplating process by interacting with gold ions, acid groups, and organic additives in the electroplating solution, thereby altering the structure and properties of the electroplated layer. Electroplating additives typically consist of various chemical substances, including complexing agents, brighteners, leveling agents, pinhole removers, dispersants, wetting agents, and smoke suppressants. The combined use of these components can significantly improve the quality and appearance of the electroplated layer. Preparation: Ensure the surfaces of workpieces one and two are clean and flat. Prepare cleaning supplies, plating agent, cleaning cloths, and drying equipment. Cleaning: Use cleaning supplies to thoroughly clean the surfaces of the items, removing oil, dust, and other impurities. Applying the plating agent: Take an appropriate amount of plating agent and slowly apply and wipe it evenly, ensuring all areas are covered. Drying: Place the items in... In a well-ventilated and dry place, allow to dry completely for approximately 8-10 hours. Maintenance: During use, avoid heavy scraping and pressure. Keep the surface of the item dry and clean. For S6 galvanized splice parts, after welding, grind the weld joints with a grinder. After grinding, wipe the surface of the galvanized splice parts with asbestos cloth to remove weld slag and spatter, then allow to cool. For S7, repeatedly apply cold galvanizing solution to the weld joints of the galvanized splice parts. (The service conditions and lifespan of electroplated zinc metal or components are closely related to the thickness of the electroplating layer. The more stringent the service conditions and the longer the service life, the thicker the required electroplating layer should be. Different products require different thicknesses depending on the temperature, humidity, rainfall, atmospheric composition, etc. Cold spray zinc is also called film galvanizing, cold galvanizing, or cold coating zinc. At room temperature, it is applied by brushing...) Zinc plating is a material protection technology that coats steel substrates with zinc using spraying, roller coating, and other methods. It's a new type of anti-corrosion process with the same rust-proof effect as hot-dip galvanizing, zinc spraying, and aluminum spraying. It's a single-component product composed of ultrafine zinc powder processed by atomic absorption spectrometry, resin, and volatile solvents. The zinc content of the coating is as high as 96%, with a purity of over 99.99% and a particle size of 3-6μm, resulting in excellent corrosion resistance to steel. After cooling the galvanized parts, they are re-inspected, corrected, and passivated. The inspection of the galvanized parts in S7 includes appearance quality (appearance quality inspection is an important basis for initially judging the quality of galvanized parts; during inspection, the main surfaces of the galvanized parts should be comprehensively visually inspected to ensure that the coating is smooth, free of drips, roughness, and zinc spikes).The coating surface should be free from defects such as peeling, incomplete coating, and residual solvent residue, especially in areas that may affect the use or corrosion resistance of the galvanized workpiece; zinc nodules and zinc ash should be avoided. Thickness (thickness is an important indicator of the quality of galvanized parts. Different applications have different requirements for galvanized layer thickness; for example, the construction industry requires a galvanized layer thickness of no less than 80 micrometers. When measuring galvanized layer thickness, an eddy current thickness gauge is usually used, and it is important to select an appropriate probe and measurement position to ensure the accuracy and representativeness of the measurement), roughness (roughness reflects the surface quality of the galvanized layer. Generally, the lower the roughness, the better the surface quality. Commonly used inspection methods include visual inspection and instrument measurement. Visual inspection mainly involves observing the surface condition of the coating with the naked eye, while instrument measurement can use equipment such as roughness meters), and adhesion (adhesion is tested by needle penetration or peel tests to check whether the zinc layer adheres to the steel plate). The requirements are met. This is an important indicator to ensure a strong bond between the galvanized layer and the steel plate. Inspection is also conducted on the chemical composition (chemical composition testing includes analyzing the chemical composition of the steel substrate and the galvanized layer to ensure the material meets the specified standards). The repair treatment of spliced ​​galvanized parts includes surface pretreatment (a crucial step in repairing galvanized parts. This includes cleaning the surface to be repaired, removing oil, rust, and other contaminants; for welded areas, slag and flying debris must be thoroughly removed by sanding or mechanical methods while protecting the undamaged zinc layer), repair, and post-treatment (mainly including removing zinc nodules, trimming edges, and improving the aesthetics and service life of the repair layer. For welded areas, Robalu cold galvanizing coating Q can be used for repair; this coating features high-efficiency corrosion protection, convenient application, and rapid drying, quickly restoring the corrosion protection effect of the galvanized layer). Passivation treatment mainly involves spraying a passivating agent onto the surface of the spliced ​​galvanized parts.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. The high-uniformity hot-dip galvanizing process according to claim 1, characterized in that: The acid solution in S1 is a sulfuric acid solution, with a temperature of 40°C and a concentration between 5% and 20%. The acid solution also contains inhibitors and corrosion inhibitors. The immersion time in the sulfuric acid solution is between 30 and 60 minutes.

2. The high-uniformity hot-dip galvanizing process according to claim 2, characterized in that: In step S2, after initially cleaning workpiece 1 and workpiece 2 by adding an appropriate amount of detergent to clean water, workpiece 1 and workpiece 2 are soaked in soapy water and rubbed vigorously in a circular motion. Then, workpiece 1 and workpiece 2 are soaked in clean water for 10-20 minutes. After soaking, a fan is used to dehumidify workpiece 1 and workpiece 2.

3. The high-uniformity hot-dip galvanizing process according to claim 3, characterized in that: The flux in S3 comprises complexing agents, brighteners, leveling agents, pinhole removers, dispersants, wetting agents, and smoke inhibitors.

4. The high-uniformity hot-dip galvanizing process according to claim 4, characterized in that: In step S5, before immersing in molten zinc, workpiece one and workpiece two are immersed in an activator to further clean the metal surface and form an oxide layer. After being washed and dried again, they are immersed in molten zinc for zinc plating.

5. The high-uniformity hot-dip galvanizing process according to claim 5, characterized in that: The asbestos cloth in S6 is made of either dust-free or dusty asbestos cloth, and is a single-layer asbestos cloth with a thickness of 0.8mm.

6. The high-uniformity hot-dip galvanizing process according to claim 6, characterized in that: In S6, the welding process involves welding workpiece one to workpiece two using automated solid-state laser welding. Flux is added during the welding process, and the main components of the flux are a mixture of rosin, resin, and halogen compounds.

7. The high-uniformity hot-dip galvanizing process according to claim 7, characterized in that: After welding, the welded joints of the S6 spliced ​​galvanized parts are ground with a grinding machine. After grinding, the weld slag and spatter on the surface of the spliced ​​galvanized parts are wiped with asbestos cloth and then cooled.

8. The high-uniformity hot-dip galvanizing process according to claim 8, characterized in that: The inspection of the spliced ​​galvanized parts in S7 includes checking the appearance quality, thickness, roughness, adhesion and chemical composition. The correction treatment of the spliced ​​galvanized parts includes surface pretreatment, repair and post-treatment. The passivation treatment is mainly carried out by spraying passivating agent on the surface of the spliced ​​galvanized parts.