A production process for improving the surface quality and stamping performance of aluminized zinc steel

Abstract

The application discloses a production process for improving the surface quality and stamping performance of aluminized zinc plated strip steel, and relates to the technical field of refrigerator back plate manufacturing.The production process for improving the surface quality and stamping performance of aluminized zinc plated strip steel comprises the following steps: raw material preparation and pretreatment, selecting a steel base plate as a base material, performing cleaning and oil removal pretreatment operations on the steel base plate after acid rolling, rinsing the steel base plate clean with clean water, and obtaining an aluminized zinc plated steel coil through heat treatment, aluminized zinc plating treatment, post-plating cooling and subsequent coating post-treatment film; the raw material preparation and pretreatment, heat treatment, aluminized zinc plating treatment, post-plating cooling and subsequent treatment and other multiple links are comprehensively optimized, the surface quality and stamping performance of the aluminized zinc plated strip steel are significantly improved, and the production process has good flexibility and adaptability, and can meet the needs of different industries, and exhibits significant advantages in improving product quality and production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of refrigerator back panel manufacturing technology, specifically, it relates to a production process for improving the surface quality and stamping performance of aluminized zinc strip steel. Background Technology

[0002] The back panel of a refrigerator provides important functions such as heat preservation, heat insulation, blocking, and moisture protection. In the existing technology, the back panel of a refrigerator is generally made of alloy steel plate by stamping.

[0003] A production process for hard hot-dip galvanized sheet, disclosed in CN103556096A, includes: uncoiling the raw material, passing it through a welding machine and an inlet looper, chemically degreasing and electrolytically degreasing it, then placing it in an annealing furnace for reduction calcination at 500 degrees Celsius. The raw material is then reheated before entering a zinc pot for hot-dip galvanizing. Afterwards, it is cooled, leveled, and treated with anti-corrosion measures. After entering the outlet looper for buffering, it is oiled, sheared, and recoiled. The beneficial effects of this method, as described above, are that the design is reasonable. It reduces the original annealing temperature of the substrate from approximately 800 degrees Celsius to approximately 500 degrees Celsius, reheats it before entering the zinc pot, and cools it after exiting the zinc pot. While achieving the quality requirements of the galvanizing / aluminized zinc-silicon plating process, it retains as much of the work-hardening characteristics of the substrate raw material during cold rolling as possible, and preserves as much of the high strength and high hardness mechanical properties of the cold-rolled substrate as possible.

[0004] In the traditional steel aluminized zinc production process, in order to control the heating power of the zinc pot, the temperature of the strip entering the pot is often controlled at a level close to that of the zinc pot to prevent zinc dross from churning and adhering to the surface of the strip, forming defects and affecting surface quality. However, when producing products with high surface quality, the problem of zinc dross accumulation in the zinc pot may be difficult to completely solve, and the problem of coating brittleness has not been effectively improved. This may lead to cracks in the coating of aluminized zinc strip during the stamping process, and the sheet may be prone to stamping cracks, which greatly limits its use in the application scenarios required for refrigerator back panel production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a production process for improving the surface quality and stamping performance of aluminized zinc strip steel that can overcome or at least partially solve the above problems.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is: a production process for improving the surface quality and stamping performance of aluminized zinc strip steel, comprising the following steps:

[0007] Step 1: Raw material preparation and pretreatment: Select a steel substrate as the base material, and then perform hot rolling on the selected steel substrate.

[0008] Step 2, Chemical treatment: The hot-rolled steel substrate is pickled and cold-rolled to obtain a hardened plate, which is then cleaned by alkaline washing and electrolytic cleaning.

[0009] Step 3, heat treatment: The steel plate is sent into a nitrogen-hydrogen protected horizontal furnace for continuous annealing. The temperature of the annealing soaking zone is controlled at 760-780℃ and the soaking time is maintained at 25-35 seconds. After annealing, the plate is cooled to 590-600℃ by purging with protective gas.

[0010] Step 4, Coating: In the initial stage, the strip steel is preheated to a temperature range 50-100℃ lower than the zinc pot temperature before being fed into the zinc pot. The zinc pot is then operated at high power (more than 60% higher than the rated power of the zinc pot) to cause the zinc dross to churn. Next, strip steel with low surface requirements (such as building materials) is fed into the zinc pot sequentially, and the churning zinc dross is removed after 2-4 hours. Once the zinc pot is relatively clean (meeting the requirements for high-surface-quality steel plates), the temperature of the strip steel entering the pot is adjusted to a normal level close to the zinc pot temperature. The normal level refers to a temperature difference controlled within ±10℃, and high-surface-quality aluminized zinc-coated strip steel is produced. Through the above technical means, the ability to produce high-surface-quality aluminized zinc-coated steel plates is obtained.

[0011] Step 5: Post-plating cooling: After the strip steel exits the zinc bath and is purged with an air knife to control the plating thickness, it is air-cooled at a rate of 5-10℃·s⁻¹ within a 1.5-meter height area between the air knife and the high-flow-rate air box. Then, it enters the high-flow-rate air box and is cooled at a rate of 15-30℃·s⁻¹ until the surface temperature does not exceed 200℃. By increasing the intensity of post-plating cooling through the above measures, the brittleness of the plating can be reduced, thereby reducing plating cracks during the stamping process and lowering the probability of stamping cracks.

[0012] Step Six: Post-processing: Perform surface post-treatment on the galvanized strip in sequence, then roll it up and inspect its quality.

[0013] Furthermore, the increased cooling intensity after coating in step four is achieved through the following methods:

[0014] Cooling equipment optimization: Select high-efficiency cooling equipment and increase the number of cooling nozzles to make the cooling medium contact the coating more evenly and quickly;

[0015] Cooling process parameter adjustment: Based on the thickness and material of the coating and the performance of the cooling equipment, the cooling time is shortened to 70%-80% of the original, the temperature of the cooling medium is reduced by 10-20℃, and the flow rate is increased by 20%-30%.

[0016] Furthermore, in subsequent processing, step six can include cleaning and applying a fingerprint-resistant film.

[0017] Furthermore, before aluminum-zinc plating, the strip steel undergoes surface activation treatment to enhance the wettability between the coating and the substrate.

[0018] Furthermore, during the production process, the substrate is cleaned to remove grease, oxides, and impurities from its surface, thereby increasing surface roughness and wettability.

[0019] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: The present invention achieves a significant improvement in the surface quality and stamping performance of aluminum-zinc coated steel strip by comprehensively optimizing multiple links such as raw material preparation and pretreatment, chemical treatment, heat treatment, aluminum-zinc coating treatment, post-coating cooling and subsequent treatment. It also has good flexibility and adaptability, can meet the needs of different industries, and shows significant advantages in improving product quality and production efficiency. Detailed Implementation

[0020] To enhance understanding of the present invention, the following detailed description of the solution is provided in conjunction with embodiments.

[0021] Example 1:

[0022] A production process for improving the surface quality and stamping performance of aluminized zinc strip steel includes the following steps:

[0023] Step 1: Raw material preparation and pretreatment:

[0024] A steel substrate is selected as the base material, and then the selected steel substrate is subjected to hot rolling.

[0025] It should be noted that the specific implementation method for the pretreatment of the steel substrate is as follows:

[0026] The steel substrate is placed in a heating furnace for heating treatment. After being heated to 1150-1200℃ in the heating furnace, it is hot rolled. The hot rolling is a two-stage rolling process. The roughing is a 5-pass continuous rolling and the finishing is a 7-pass continuous rolling. The finishing temperature is 900℃-920℃. Laminar flow cooling is used in the back-end cooling. The coiling temperature is 650℃-660℃ to obtain the hot-rolled steel coil.

[0027] Step Two: Chemical Treatment: The hot-rolled steel substrate is pickled and cold-rolled to obtain a hardened sheet, which is then subjected to alkaline washing and electrolytic cleaning.

[0028] It should be noted that the specific implementation steps for chemical treatment of the hot-rolled steel substrate are as follows:

[0029] The deep-drawing cold-rolled hardened steel sheet has a cold rolling reduction rate of 80-90%. After cold rolling, the hardened strip is subjected to alkaline washing with NaOH solution at a concentration of 1.5-1.8% and a temperature of 78-82℃; then it is subjected to electrolytic cleaning with a current density of 5-8C / dm2; and finally, it is rinsed with hot water at a temperature of 75-85℃.

[0030] It should also be noted that the slab heating temperature is 1150-1200℃ to ensure complete austenitization and hot working requirements.

[0031] Final rolling temperature: To avoid the material entering the two-phase region during rolling and causing mixed crystals, the final rolling temperature should be higher than the Ar3 phase transformation point. However, excessively high temperatures can cause oxidation on the steel plate surface, forming iron oxide scale, which is detrimental to subsequent hot-dip aluminum-zinc galvanizing. This invention sets the final rolling temperature at 900℃-920℃.

[0032] Coiling temperature: Increasing the coiling temperature is beneficial for the coarsening of precipitates, subsequent cold rolling annealing, and the deep drawing performance of the steel sheet. However, excessively high coiling temperatures can lead to further oxidation of the steel strip surface during coiling. Actual research shows that higher temperatures result in thicker surface oxide scale, which is less conducive to surface pickling for removing the oxide scale and negatively impacts the adhesion between the aluminum-zinc plating and the substrate. Therefore, a coiling temperature of 650-660℃ is recommended.

[0033] Sourcing compression ratio: Based on the mill's production capacity, the compression ratio is normally set at 80-90%.

[0034] Cleaning process parameters: To ensure that there is no residual grease on the steel plate surface during immersion plating and to obtain good adhesion between the plating layer and the substrate, the cleaning process was designed. The concentration and temperature of the NaOH solution for alkaline cleaning affect the surface cleanliness of the steel plate. Too low a concentration and temperature will not achieve good cleaning results, while too high a concentration and temperature will significantly increase production costs. Through repeated verification, a NaOH solution concentration of 1.5-1.8% and a NaOH solution temperature of 78-82℃ were set to achieve the desired alkaline cleaning effect. Electrolytic cleaning directly affects the removal of residual grease from the steel plate surface after alkaline cleaning; the current density setting is crucial. Too low a current density will not achieve the desired residue removal effect. Based on the actual equipment capacity, the current density was set to 5-8 C / dm². Hot water rinsing with a hot water temperature of 75-85℃ effectively rinses away residual alkaline solution from the steel strip surface.

[0035] Annealing furnace heating section temperature: Research has shown that for strip steel heated by direct combustion nozzles, the steel is in a slightly oxidized state in the heating section. The higher the temperature, the easier it is to oxidize. The oxidized surface is not conducive to the adhesion of the coating during subsequent hot-dip galvanizing. In order to meet the annealing requirements of steel plates and to prevent oxidation, the heating temperature is set at 630℃-650℃.

[0036] Annealing soaking section process: To ensure sufficient recrystallization and growth of the steel plate, a high annealing temperature is required. However, excessively high temperatures will inevitably lead to oxidation of the steel plate in a moisture-containing environment (dew point). Research has shown that it is necessary to control the steel plate temperature, dew point, and oxygen content in the furnace gas. This invention sets the soaking section temperature at 760-780℃, the dew point of the annealing furnace soaking section at -40-50℃, and the oxygen content at 20-30ppm.

[0037] Step 3: Heat Treatment

[0038] Annealing treatment:

[0039] The steel plate was continuously annealed in a nitrogen-hydrogen protected horizontal furnace. The temperature of the annealing soaking zone was set to 770℃, and the soaking time was 30 seconds. Under this temperature and time, the internal stress of the steel plate could be effectively eliminated, and its microstructure improved.

[0040] Cooling operation:

[0041] After annealing, the steel plate is purged and cooled to 592°C using a nitrogen-hydrogen protective gas with a volume ratio of 90:10 to prevent oxidation during the cooling process.

[0042] Step 4: Coating

[0043] Initial setup of the zinc pot and cleaning of zinc dross:

[0044] Set the zinc pot temperature to 580℃, preheat the strip steel to 490℃ (90℃ lower than the zinc pot temperature) and then put it into the zinc pot. Adjust the heating power of the zinc pot to the maximum to make the zinc dross churn.

[0045] Prepare 8 rolls of low-surface-requirement steel strips and feed them sequentially into the zinc pot at a speed of 130 meters per minute. Run the process continuously for 3 hours to remove zinc dross. Observe the inside of the zinc pot; when the zinc dross is significantly reduced, the zinc pot is considered to have reached a relatively clean state.

[0046] Production of high surface quality products:

[0047] Adjust the temperature of the strip steel entering the pot to 585℃ (close to the temperature of the zinc pot, with a temperature difference within ±10℃) to start the production of high surface quality aluminized zinc strip steel.

[0048] Coating thickness control:

[0049] The coating thickness was controlled using an air knife. The air knife pressure was set to 0.25 MPa, and the coating thickness was controlled to 90 g / m² on both sides by adjusting the distance between the air knife and the strip and the airflow speed. 2 This ensures that the coating adheres evenly to the surface of the strip steel.

[0050] Step 5: Cooling after coating

[0051] Cooling equipment optimization:

[0052] In the original cooling system, six specially designed cooling nozzles were added to spray the cooling medium (water) evenly onto the strip surface in a spiral pattern, thereby improving cooling efficiency and uniformity.

[0053] Cooling process parameter adjustment:

[0054] After the strip steel exits the zinc bath and the coating thickness is controlled by air knife purging, it is air-cooled in a height area of ​​about 1.5 meters above the air knife and between the high-flow-rate air box at a cooling rate of 7℃·s-1.

[0055] After entering the high-flow-rate air box, based on the coating thickness (approximately 12μm) and material (specific steel composition) of this batch of aluminum-zinc coated steel strip, the cooling time is shortened to 75% of the original design, the temperature of the cooling medium (air) is reduced by 15℃, the flow rate is increased by 22%, and the steel strip is cooled at a rate of 22℃·s-1 until its surface temperature drops to 190℃.

[0056] Step Six: Follow-up Processing

[0057] Surface post-treatment:

[0058] Fingerprint-resistant coating: Apply fingerprint-resistant liquid and dry to form a fingerprint-resistant film, improving corrosion resistance.

[0059] Reeling operation:

[0060] An automatic winding machine is used to wind the aluminized zinc-coated steel strip that has undergone surface post-treatment. The winding tension is set to 4.5kN to ensure that the steel strip is wound tightly and the end face is flat.

[0061] Quality inspection:

[0062] Surface quality inspection: Ensure that there is no zinc residue or obvious defects on the surface, and that the coating is uniform.

[0063] Coating thickness measurement: A high-precision coating thickness gauge was used to measure the coating thickness at multiple locations, with the thickness error required to be controlled within ±5g / m. 2 Inside.

[0064] Stamping performance test: The strip steel is stamped using a stamping testing machine. The shape and surface condition after stamping are observed. It is required that there are no cracks or obvious deformation after stamping, and the stamping performance requirements of the refrigerator back panel are met.

[0065] Example 2: A production process for improving the surface quality and stamping performance of aluminized zinc strip steel, comprising the following steps:

[0066] Step 1: Raw material preparation and pretreatment:

[0067] A steel substrate is selected as the base material, and then the selected steel substrate is subjected to hot rolling.

[0068] It should be noted that the specific implementation method for the pretreatment of the steel substrate is as follows:

[0069] The steel substrate is placed in a heating furnace for heating treatment. After being heated to 1150-1200℃ in the heating furnace, it is hot rolled. The hot rolling is a two-stage rolling process. The roughing is a 5-pass continuous rolling and the finishing is a 7-pass continuous rolling. The finishing temperature is 900℃-920℃. Laminar flow cooling is used in the back-end cooling. The coiling temperature is 650℃-660℃ to obtain the hot-rolled steel coil.

[0070] Step Two: Chemical Treatment: The hot-rolled steel substrate is pickled and cold-rolled to obtain a hardened sheet, which is then subjected to alkaline washing and electrolytic cleaning.

[0071] It should be noted that the specific implementation steps for chemical treatment of the hot-rolled steel substrate are as follows:

[0072] The deep-drawing cold-rolled hardened steel sheet has a cold rolling reduction rate of 80-90%. After cold rolling, the hardened strip is subjected to alkaline washing with NaOH solution at a concentration of 1.5-1.8% and a temperature of 78-82℃; then it is subjected to electrolytic cleaning with a current density of 5-8C / dm2; and finally, it is rinsed with hot water at a temperature of 75-85℃.

[0073] Step 3: Heat Treatment

[0074] Annealing treatment:

[0075] The steel plate was fed into a nitrogen-hydrogen protected horizontal furnace for continuous annealing. The temperature of the annealing soaking zone was set at 760℃ and the soaking time was 30 seconds, which optimized the microstructure of the steel plate.

[0076] Cooling operation:

[0077] After annealing, the steel plate is purged and cooled to 598°C using a nitrogen-hydrogen protective gas with a volume ratio of 92:8.

[0078] Step 4: Coating

[0079] Initial setup of the zinc pot and cleaning of zinc dross:

[0080] Set the zinc pot temperature to 620℃, preheat the strip steel to 530℃ (90℃ lower than the zinc pot temperature) and then put it into the zinc pot. At the same time, adjust the heating power of the zinc pot to the maximum to make the zinc dross churn.

[0081] Prepare 12 rolls of steel with low surface finish requirements and feed them sequentially into the zinc pot at a speed of 135 meters per minute. The process continues for 2.8 hours to remove zinc dross. The zinc pot is considered to have reached a relatively clean state when a significant reduction in zinc dross is observed.

[0082] Production of high surface quality products:

[0083] Adjust the temperature of the strip steel entering the pot to 615℃ (close to the temperature of the zinc pot, with a temperature difference within ±10℃) to start the production of high surface quality aluminized zinc strip steel.

[0084] Coating thickness control:

[0085] The coating thickness was controlled using an air knife. The air knife pressure was set to 0.32 MPa, and the coating thickness was controlled to 85 g / m² on both sides by adjusting the distance between the air knife and the strip and the airflow speed. 2 This ensures the uniformity of the coating.

[0086] Step 5: Cooling after coating

[0087] Cooling equipment optimization:

[0088] In the original cooling system, eight atomizing nozzles were installed. These nozzles produce finer droplets, allowing the cooling medium (water) to more evenly cover the surface of the strip steel. At the same time, the pressure of the cooling medium is increased, improving cooling efficiency.

[0089] Cooling process parameter adjustment:

[0090] After the strip steel exits the zinc bath and the coating thickness is controlled by air knife purging, it is air-cooled in a 1.5-meter height area between the air knife and the high-flow-rate air box at a cooling rate of 9℃·s-1.

[0091] After entering the high-flow-rate air box, based on the coating thickness (approximately 15 μm) and material (known steel composition) of this batch of aluminum-zinc coated steel strip, the cooling time is shortened to 72% of the original design, the temperature of the cooling medium (air) is reduced by 18°C, the flow rate is increased by 28%, and the steel strip is cooled at a rate of 28°C·s⁻¹ until its surface temperature drops to 185°C.

[0092] Step Six: Follow-up Processing

[0093] Surface post-treatment:

[0094] Fingerprint-resistant coating: Apply fingerprint-resistant liquid and dry to form a fingerprint-resistant film, improving corrosion resistance.

[0095] Reeling operation:

[0096] A high-precision winding machine is used to wind the galvanized steel strip with a winding tension of 5.5kN to ensure the quality of the steel strip winding.

[0097] Quality inspection:

[0098] Surface quality inspection: The surface of the strip steel is inspected to ensure that there is no zinc dross residue, the surface is smooth and the coating is uniform.

[0099] Coating thickness measurement: The coating thickness was measured at different locations using a coating thickness gauge to ensure that the thickness error was within ±4g / m. 2 Inside.

[0100] Stamping performance test: Stamping test is performed on the strip steel, and the performance after stamping is observed. It is required that there are no cracks or deformations and that the stamping performance requirements of steel for home appliance manufacturing are met.

[0101] Example 3: A production process for improving the surface quality and stamping performance of aluminized zinc strip steel, comprising the following steps:

[0102] Step 1: Raw material preparation and pretreatment:

[0103] A steel substrate is selected as the base material, and then the selected steel substrate is subjected to hot rolling.

[0104] It should be noted that the specific implementation method for the pretreatment of the steel substrate is as follows:

[0105] The steel substrate is placed in a heating furnace for heating treatment. After being heated to 1150-1200℃ in the heating furnace, it is hot rolled. The hot rolling is a two-stage rolling process. The roughing is a 5-pass continuous rolling and the finishing is a 7-pass continuous rolling. The finishing temperature is 900℃-920℃. Laminar flow cooling is used in the back-end cooling. The coiling temperature is 650℃-660℃ to obtain the hot-rolled steel coil.

[0106] Step Two: Chemical Treatment: The hot-rolled steel substrate is pickled and cold-rolled to obtain a hardened sheet, which is then subjected to alkaline washing and electrolytic cleaning.

[0107] It should be noted that the specific implementation steps for chemical treatment of the hot-rolled steel substrate are as follows:

[0108] The deep-drawing cold-rolled hardened steel sheet has a cold rolling reduction rate of 80-90%. After cold rolling, the hardened strip is subjected to alkaline washing with NaOH solution at a concentration of 1.5-1.8% and a temperature of 78-82℃; then it is subjected to electrolytic cleaning with a current density of 5-8C / dm2; and finally, it is rinsed with hot water at a temperature of 75-85℃.

[0109] Step 3: Heat Treatment

[0110] Annealing treatment:

[0111] The steel plate is fed into a nitrogen-hydrogen protected horizontal furnace for continuous annealing. The temperature of the annealing soaking section is set at 760℃ and the soaking time is 35 seconds to improve the internal structure of the steel plate.

[0112] Cooling operation:

[0113] After annealing, the steel plate is purged and cooled to 596°C using a nitrogen-hydrogen protective gas with a volume ratio of 93:7.

[0114] Step 4: Coating

[0115] Initial setup of the zinc pot and cleaning of zinc dross:

[0116] Set the zinc pot temperature to 600℃, preheat the strip steel to 510℃ (90℃ lower than the zinc pot temperature) and then put it into the zinc pot. Adjust the heating power of the zinc pot to the maximum to make the zinc dross churn.

[0117] Nine rolls of steel with low surface finish requirements were prepared and sequentially fed into the zinc pot at a speed of 130 meters per minute, running continuously for 3.5 hours to remove zinc dross. Based on observation, the process proceeded to the next stage once the zinc dross removal met the requirements.

[0118] Production of high surface quality products:

[0119] Adjust the temperature of the strip steel entering the pot to 598℃ (close to the temperature of the zinc pot, with a temperature difference within ±10℃) to start the production of high surface quality aluminized zinc strip steel.

[0120] Coating thickness control:

[0121] The coating thickness was controlled using an air knife. The air knife pressure was set to 0.28 MPa, and the coating thickness was controlled to 88 g / m² on both sides by adjusting the distance between the air knife and the strip and the airflow speed. 2 This ensures uniform adhesion of the coating.

[0122] Step 5: Cooling after coating

[0123] Cooling equipment optimization:

[0124] Five air spray guns were added to the original cooling system to enhance the air cooling effect and make the cooling medium (air) contact the coating more evenly and quickly.

[0125] Cooling process parameter adjustment:

[0126] After the strip steel exits the zinc bath and the coating thickness is controlled by air knife purging, it is air-cooled in a 1.5-meter height area between the air knife and the high-flow-rate air box at a cooling rate of 6℃·s-1.

[0127] After entering the high-flow-rate air box, based on the coating thickness (approximately 13 μm) and material (known steel composition) of this batch of aluminum-zinc coated steel strip, the cooling time is shortened to 78% of the original design, the temperature of the cooling medium (air) is reduced by 12°C, the flow rate is increased by 25%, and the steel strip is cooled at a rate of 25°C·s⁻¹ until its surface temperature drops to 195°C.

[0128] Step Six: Follow-up Processing

[0129] Surface post-treatment:

[0130] Apply fingerprint-resistant film: Apply fingerprint-resistant liquid and dry to form a fingerprint-resistant film, improving corrosion resistance.

[0131] Reeling operation:

[0132] An automatic winding machine is used to wind the aluminized zinc strip steel with a winding tension of 5kN to ensure winding quality.

[0133] Quality inspection:

[0134] Surface quality inspection: The surface of the strip steel is inspected to ensure that there is no zinc dross residue and that the surface finish meets the requirements.

[0135] Coating thickness measurement: The coating thickness is measured at different locations using a precise coating thickness gauge, ensuring an error within ±5g / m². 2 Inside.

[0136] Stamping performance test: The strip steel is subjected to a stamping test, and it is required that there are no cracks or deformations after stamping, which meets the stamping performance requirements of steel used in industrial equipment manufacturing.

[0137] These examples detail the specific production processes under different conditions, including the operational details and parameter adjustments for raw material preparation, chemical treatment, heat treatment, aluminum-zinc plating, post-plating cooling, and subsequent treatments. They provide specific operational guidance for implementing this production process in various application scenarios, allowing for appropriate adjustments to process parameters based on actual production needs and equipment conditions. In actual production, strict adherence to operating procedures and safety requirements is essential to ensure product quality and the safety of the production process.

[0138] It should be noted that, in specific implementation, further optimization and adjustments can be made based on actual production conditions. At the same time, attention should be paid to the precise control and selection of process parameters, equipment parameters, and the use of chemical reagents in each step, in order to achieve the best production results and product quality.

[0139] In summary, by further improving the production process, this invention has the following beneficial effects:

[0140] I. Significant improvement in surface quality

[0141] Effectiveness of zinc dross removal:

[0142] In the coating stage, by preheating the strip steel to a temperature lower than that of the zinc pot (e.g., 90°C lower than the zinc pot temperature in Example 1) and running the zinc pot at high power to agitate the zinc dross, the strip steel with low surface requirements carries away the zinc dross for a certain period of time (e.g., 3 hours in Example 1), the amount of zinc dross in the zinc pot can be significantly reduced. This process can effectively prevent the adhesion of zinc dross to the surface of the high-surface-quality aluminized zinc strip steel, avoid surface defects caused by zinc dross, and thus significantly improve the surface quality of the product. The final aluminized zinc strip steel produced, after surface quality inspection, shows excellent characteristics of no zinc dross residue, no obvious defects, and uniform coating in different application scenarios, meeting the high requirements of home appliance manufacturing for the surface quality of strip steel.

[0143] Synergistic effect of chemical treatment and cleaning:

[0144] The chemical treatment and cleaning operations in the raw material preparation and pretreatment stage, including degreasing, rust removal, pickling, and cleaning of the steel substrate, ensure the cleanliness of the steel plate surface. From using alkaline degreasers and organic solvents to chemical alkaline washing, electrochemical rust removal, and cleaning with various alkaline solutions and deionized water, these operations not only thoroughly remove oil, rust, and iron powder from the steel plate surface but also ensure good adhesion of the subsequent coating. Different treatment methods have been optimized for different substrates and application scenarios, achieving a highly clean steel plate surface, reducing the impact of impurities on coating quality, and laying the foundation for obtaining a high-quality aluminum-zinc coated steel strip surface.

[0145] Moreover, the cleaning operation in the subsequent processing can effectively remove impurities from the surface of the plated strip steel, further optimizing the surface quality of the strip steel.

[0146] It should be noted that the different choices of these cleaning solutions and the corresponding temperature, time, and pressure settings can flexibly remove various impurities that may remain, based on the characteristics of different production batches, resulting in a cleaner final product surface and reducing the impact of surface defects and impurities on the product's appearance and performance.

[0147] II. Enhanced stamping performance

[0148] The impact of post-plating cooling optimization:

[0149] This process employs several optimization measures in the post-coating cooling stage, significantly enhancing the stamping performance of the aluminized zinc strip. Through optimization of the cooling equipment, such as adding specially designed cooling nozzles to the cooling system and adjusting cooling process parameters (shortening cooling time, reducing cooling medium temperature, and increasing flow rate), effective cooling of the aluminized zinc strip coating is achieved.

[0150] For example, in Example 1, the cooling time is shortened to 75% of the original design, the temperature of the cooling medium (air) is reduced by 15°C, the flow rate is increased by 22%, and the strip steel is cooled at a rate of 22°C·s⁻¹; in Example 2, the cooling time is shortened to 72% of the original design, the temperature of the cooling medium (air) is reduced by 18°C, the flow rate is increased by 28%, and the strip steel is cooled at a rate of 28°C·s⁻¹; in Example 3, the cooling time is shortened to 78% of the original design, the temperature of the cooling medium (air) is reduced by 12°C, the flow rate is increased by 25%, and the strip steel is cooled at a rate of 25°C·s⁻¹.

[0151] This adjustment to the cooling method alters the microstructure of the coating, refines the grains, reduces the brittleness of the coating, and prevents cracks and spalling during subsequent stamping processes.

[0152] In the stamping performance test, a stamping testing machine was used to conduct stamping tests on the aluminized zinc strip steel in different embodiments. The results showed that the stamped strip steel had no cracks or significant deformation, meeting the stringent requirements for strip steel stamping performance in different application scenarios such as home appliance manufacturing and industrial equipment manufacturing. Compared with traditional processes, this process significantly improves the reliability and stability of aluminized zinc strip steel in complex shape forming and high-strength stamping processes by optimizing post-plating cooling, thus expanding its application range in high-requirement stamping processing fields.

[0153] III. Flexibility and Adaptability of the Production Process

[0154] Applicability to different raw materials and process parameters:

[0155] This production process can be flexibly adjusted according to different substrate specifications and product requirements. Starting with the selection of substrates of different thicknesses (such as 0.8mm, 1.0mm, 1.2mm) and widths (such as 1100mm, 1200mm), it shows that this process can be adapted to different product size and shape requirements.

[0156] Meanwhile, the selection of different process parameters and treatment agents for degreasing, rust removal, pickling, cooling, and fingerprint-resistant coating demonstrates the flexibility of this process in various application scenarios. Whether using alkaline degreasing agents, organic solvents, pickling solutions of different concentrations, or adjusting different cooling nozzles and cooling media, the process can be optimized and combined according to actual production equipment and conditions, making it suitable for various product types and production environments. This meets the diverse needs of different industries such as home appliance manufacturing and industrial equipment manufacturing for aluminized zinc strip steel.

[0157] Improved quality stability and reliability:

[0158] This process can consistently produce high-quality aluminized zinc strip steel under different parameter and operational detail adjustments. From cleaning zinc dross from the zinc pot to controlling the coating thickness (by adjusting air knife pressure and airflow speed), and then to subsequent cleaning, fingerprint-resistant film coating, winding, and quality inspection, each step has undergone meticulous operation and parameter optimization to ensure product quality stability.

[0159] For product quality inspection in different industries, such as the precise measurement of coating thickness (error controlled within ±6g / m²), 2 Up to ±4g / m 2 The rigorous inspection of surface quality and the testing of stamping performance demonstrate that this process can reliably ensure the consistency of product quality across different batches and under different production conditions. This provides reliable technical support for large-scale industrial production, reduces product defect rates caused by quality instability, and improves production efficiency and economic benefits.

[0160] In summary, this production process, through comprehensive optimization of multiple stages including raw material preparation and pretreatment, chemical treatment, heat treatment, aluminized zinc plating, post-plating cooling, and subsequent treatments, achieves a significant improvement in the surface quality and stamping performance of aluminized zinc strip steel. It also possesses excellent flexibility and adaptability, meeting the needs of the home appliance industry. This provides an efficient and reliable production process for aluminized zinc strip steel, demonstrating significant advantages in improving product quality and production efficiency. Furthermore, strict adherence to operating procedures and safety requirements during actual production ensures the safety and sustainability of the production process.

[0161] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A production process for improving the surface quality and stamping performance of aluminized zinc strip steel, characterized in that, Includes the following steps: Step 1: Raw material preparation and pretreatment: Select a steel substrate as the base material, and then perform hot rolling on the selected steel substrate. Step 2, Chemical treatment: The hot-rolled steel substrate is pickled and cold-rolled to obtain a hardened plate, which is then cleaned by alkaline washing and electrolytic cleaning. Step 3, heat treatment: The steel plate is sent into a nitrogen-hydrogen protected horizontal furnace for continuous annealing. The temperature of the annealing soaking zone is controlled at 760-780℃ and the soaking time is maintained at 25-35 seconds. After annealing, the plate is cooled to 590-600℃ by purging with protective gas. Step 4, Coating: In the initial stage, the strip steel is preheated to a temperature range 50-100℃ lower than the zinc pot temperature and then fed into the zinc pot. The zinc pot is then run at high power to cause the zinc dross to churn. Next, strip steel with low surface requirements is fed into the zinc pot in sequence, and the churning zinc dross is removed after 2-4 hours. After the zinc pot is relatively clean, the temperature of the strip steel entering the pot is adjusted to a normal level close to the temperature of the zinc pot. The normal level means that the temperature difference is controlled within ±10℃, and high surface quality aluminum-zinc coated strip steel is produced. Step 5: Cooling after coating: After the strip steel exits the zinc pot molten pool and is purged by an air knife to control the coating thickness, it is air-cooled in a 1.5-meter height area between the air knife and the high-flow-rate air box at a cooling rate of 5-10℃·s-1. Then it enters the high-flow-rate air box and is cooled at a rate of 15-30℃·s-1 until the surface temperature does not exceed 200℃. Step Six: Post-processing: Perform surface post-treatment on the galvanized strip in sequence, then roll it up and inspect its quality.

2. The production process for improving the surface quality and stamping performance of aluminized zinc strip steel according to claim 1, characterized in that, The increased cooling intensity after coating in step four is achieved through the following methods: Cooling equipment optimization: Select high-efficiency cooling equipment and increase the number of cooling nozzles to make the cooling medium contact the coating more evenly and quickly; Cooling process parameter adjustment: Based on the thickness and material of the coating and the performance of the cooling equipment, the cooling time is shortened to 70%-80% of the original, the temperature of the cooling medium is reduced by 10-20℃, and the flow rate is increased by 20%-30%.

3. The production process for improving the surface quality and stamping performance of aluminized zinc strip steel according to claim 2, characterized in that, In subsequent processing, step six can involve cleaning and applying a fingerprint-resistant film.

4. The production process for improving the surface quality and stamping performance of aluminized zinc strip steel according to claim 2, characterized in that, Before aluminum-zinc plating, the strip steel is subjected to surface activation treatment to enhance the wettability between the coating and the substrate.

5. A production process for improving the surface quality and stamping performance of aluminized zinc strip steel according to claim 2, characterized in that, During the production process, the substrate is cleaned to remove grease, oxides and impurities from the surface, thereby increasing surface roughness and wettability.