A steel sheet hot dip galvanizing apparatus

Abstract

This invention relates to a hot-dip galvanizing processing apparatus for steel plates, comprising an inlet section, a pretreatment section, an annealing section, a galvanizing section, a post-treatment section, and an outlet section arranged sequentially along the steel plate's running direction. The galvanizing section includes a zinc pot and is equipped with an online zinc dross separation and recovery subsystem. This subsystem includes a zinc liquid circulation pump connected to the bottom of the zinc pot, with its outlet connected to the inlet of an electromagnetic induction zinc dross separator. The outlet of the electromagnetic induction zinc dross separator is connected to the upper part of the zinc pot. The galvanizing section is equipped with a first X-ray thickness gauge, and the post-treatment section is equipped with a second X-ray thickness gauge. Both the first and second X-ray thickness gauges are connected to a central controller. The beneficial effects of this invention are: significantly improved coating thickness control accuracy, effective suppression of zinc dross defects, fundamental improvement in the plating suitability of high-strength steel, significant reduction in zinc raw material consumption, and substantial improvement in coating uniformity and surface quality.

Description

Technical Field

[0001] This invention belongs to the field of steel plate processing and manufacturing technology, and specifically relates to a steel plate hot-dip galvanizing processing device. Background Technology

[0002] Continuous hot-dip galvanizing of steel sheets is a crucial step in cold-rolled deep processing. Its basic principle involves continuously immersing annealed cold-rolled steel sheets in molten zinc, forming a metallic zinc coating on the steel surface to achieve corrosion prevention and protection. However, with the automotive and home appliance manufacturing industries continuously raising their requirements for steel sheet surface quality and corrosion resistance, the hot-dip galvanizing process faces a series of pressing technical challenges.

[0003] Insufficient precision in coating thickness control: Currently, hot-dip galvanizing production lines generally use air knife purging to control coating thickness. This involves adjusting parameters such as the distance between the air knife and the steel plate surface, and the air knife pressure. However, due to uncertainties such as vibration, tension fluctuations, and temperature changes during continuous operation, coating thickness fluctuations have been a persistent problem, leading to decreased product qualification rates and increased zinc raw material consumption.

[0004] Zinc dross defects are difficult to effectively suppress: During the hot-dip galvanizing process of steel plates, uneven temperature distribution in the preceding processes, resulting in lower temperatures at the edges of the steel plates, easily leads to zinc dross defects. Zinc dross defects have a fatal impact on the surface quality of galvanized steel plates and severely affect the scrap rate and production efficiency of the entire production line. Existing zinc dross removal devices are mostly offline or semi-automatic, unable to achieve online real-time removal.

[0005] Poor coordination among process steps: In existing hot-dip galvanizing production lines, the pretreatment, annealing, galvanizing, cooling, and passivation processes operate independently, lacking global information exchange and collaborative control. Parameter adjustments at each stage rely on the operator's experience and judgment, making it impossible to achieve closed-loop optimization control based on real-time data.

[0006] High-strength steel faces significant challenges in galvanization: With the advancement of lightweighting in automobiles, the application of high-strength steels (such as DP steel and TRIP steel) is becoming increasingly widespread. However, alloying elements such as Si and Mn in high-strength steel are prone to selective oxidation during annealing, forming an oxide film on the steel plate surface. This severely affects the wettability of the steel plate, leading to defects such as incomplete galvanization or failure to galvanize during the galvanizing process. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a hot-dip galvanizing processing device for steel plates that enables online closed-loop control of coating thickness, real-time removal of zinc dross, coordinated linkage of various process steps, and improved plating applicability of high-strength steel.

[0008] This invention is achieved through the following technical solution: A hot-dip galvanizing processing apparatus for steel plates includes an inlet section, a pretreatment section, an annealing section, a galvanizing section, a post-treatment section, and an outlet section arranged sequentially along the running direction of the steel plate. The galvanizing section includes a zinc pot, and an air knife assembly is provided above the zinc pot. The apparatus is characterized in that: the galvanizing section is equipped with an online zinc dross separation and recovery subsystem, which includes a zinc liquid circulation pump connected to the bottom of the zinc pot, an outlet of which is connected to the inlet of an electromagnetic induction zinc dross separator, and an outlet of which is connected to the upper part of the zinc pot; the galvanizing section is equipped with a first X-ray thickness gauge, and the post-treatment section is equipped with a second X-ray thickness gauge, both of which are connected to a central controller.

[0009] The electromagnetic induction zinc slag separator is equipped with multiple sets of electromagnetic induction coils and ceramic filter screens arranged alternately along the direction of zinc liquid flow.

[0010] A zinc slag collection container is provided below the electromagnetic induction zinc slag separator.

[0011] The air knife assembly includes an upper air knife and a lower air knife, which are respectively mounted on the air knife support via a servo adjustment mechanism.

[0012] The servo adjustment mechanism includes a servo motor, on which a lead screw and nut assembly is mounted. The lead screw and nut assembly is connected to the upper or lower air knife and moves linearly along the guide rail.

[0013] The air inlet ends of the upper and lower air knives are respectively connected to an air pressure regulating valve and an air flow meter.

[0014] An online surface cleanliness detection unit is provided between the pretreatment section and the annealing section. The online surface cleanliness detection unit includes an ultraviolet fluorescence excitation light source and an ultraviolet fluorescence detection camera located on both sides of the steel plate.

[0015] The bottom of the zinc pot is equipped with a gradient heating device, which includes multiple independently temperature-controlled induction heating coils arranged at intervals along the width of the zinc pot. Each induction heating coil is connected to an independent power supply module.

[0016] A pre-nickel plating unit is provided between the annealing section and the zinc pot. The pre-nickel plating unit includes a vacuum plating chamber, which contains several sets of nickel targets and magnetron sputtering sources. The vacuum plating chamber is connected to a vacuum pump group and an inert gas supply system.

[0017] The inlet section includes an uncoiler, pinch rolls, and an inlet looper.

[0018] The pretreatment section includes a degreasing and cleaning unit, an electrolytic cleaning unit, a hot water rinsing unit, and a hot air drying unit.

[0019] The annealing section includes a continuous annealing furnace, which is divided into a heating zone, a soaking zone, a slow cooling zone, and a fast cooling zone along the running direction of the steel plate.

[0020] The zinc pot is equipped with a submerging roller, and a stabilizing roller is provided above the submerging roller.

[0021] The post-processing section includes an alloying heating furnace, a post-plating cooling unit, a finishing machine, and a passivation coating unit. The post-plating cooling unit includes atomizing cooling sprayers installed on both sides of the steel plate. The atomizing cooling sprayers are connected to a cooling water circulation system and a compressed air supply system. Cooling air knives are installed behind the atomizing cooling sprayers.

[0022] The passivation coating unit includes a roller coater connected to a passivation liquid circulation supply system, and an infrared drying oven is provided behind the roller coater.

[0023] The exit section includes an exit looper and a winding machine.

[0024] The beneficial effects of this invention are: 1. Significantly improved coating thickness control accuracy: The thickness of the zinc layer after galvanizing and after the finished product is detected online by the first X-ray thickness gauge and the second X-ray thickness gauge respectively. Combined with the multi-source sensor fusion decision module of the central controller, real-time feedback control and feedforward feedback composite control of coating thickness are realized, which effectively eliminates the influence of factors such as steel plate vibration and tension fluctuation on coating thickness. The coating thickness deviation can be controlled within ±3%.

[0025] 2. Zinc dross defects were effectively suppressed: By setting up an electromagnetic induction zinc dross separator, a gradient magnetic field was used to drive and intercept zinc dross particles in the zinc bath towards the ceramic filter screen, achieving continuous online separation and recovery of zinc dross. Compared with the traditional manual dross removal method, the zinc dross removal efficiency was significantly improved. At the same time, the gradient heating device independently adjusted the temperature of different width areas of the zinc pot, effectively eliminating zinc dross defects caused by uneven zinc bath temperature.

[0026] 3. The plating susceptibility of high-strength steel has been fundamentally improved: A pre-plating nickel unit is set between the annealing section and the galvanizing section. A nickel pre-plating layer is deposited on the steel plate surface by magnetron sputtering, which effectively avoids the deterioration of wettability caused by the selective oxidation of alloying elements such as Si and Mn in high-strength steel. This fundamentally solves the problems of missed plating and no plating during the galvanizing process of high-strength steel.

[0027] 4. Coordinated operation of each link: Through the multi-source sensor fusion decision module of the central controller, the detection units and actuators of the pre-processing section, annealing section, galvanizing section and post-processing section are incorporated into a unified control network, realizing global coordinated optimization control based on real-time data.

[0028] 5. Significantly reduced zinc raw material consumption: Through precise closed-loop control of coating thickness and online recycling of zinc dross, the consumption of zinc raw materials is effectively reduced, by 8% to 15%.

[0029] 6. Coating uniformity and surface quality have been greatly improved: The temperature distribution in the width direction of the steel plate after annealing is detected in real time by the online temperature field detection unit on the steel plate surface. Combined with the independent temperature adjustment of each area of ​​the zinc pot by the gradient heating device, the uneven coating thickness and surface defects caused by uneven temperature are effectively eliminated. Attached Figure Description

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] Appendix Figure 1 This is a schematic diagram of the overall structure of the present invention; Appendix Figure 2 This is a schematic diagram of the air knife assembly installation structure of the present invention; Appendix Figure 3 This is a schematic diagram of the zinc slag online separation and recovery subsystem of the present invention; Appendix Figure 4 This is a schematic diagram of the pre-nickel plating unit structure of the present invention; Appendix Figure 5 This is a schematic diagram of the online temperature field detection unit for the steel plate surface of the present invention; Appendix Figure 6 This is a schematic diagram of the post-plating cooling unit structure of the present invention; Appendix Figure 7 This is a schematic diagram of the control principle structure of the central controller of the present invention; In the diagram, 1 is the steel plate, 2 is the inlet section, 3 is the pretreatment section, 4 is the annealing section, 5 is the galvanizing section, 6 is the post-treatment section, 7 is the outlet section, 8 is the zinc pot, 9 is the air knife assembly, 10 is the online zinc slag separation and recovery subsystem, 11 is the zinc liquid circulation pump, 12 is the electromagnetic induction zinc slag separator, 13 is the first X-ray thickness gauge, 14 is the second X-ray thickness gauge, 15 is the central controller, 16 is the electromagnetic induction coil, 17 is the ceramic filter screen, 18 is the zinc slag collection container, 19 is the upper air knife, 20 is the lower air knife, 21 is the servo adjustment mechanism, 22 is the servo motor, 23 is the lead screw and nut pair, 24 is the guide rail, 25 is the air pressure regulating valve, 26 is the air flow meter, 27 is the online surface cleanliness detection unit, 28 is the ultraviolet fluorescence excitation source, 29 is the ultraviolet fluorescence detection camera, 30 is the gradient heating device, 31 is the induction heating coil, 32 is the power module, 33 is the pre-nickel plating unit, 34 is the vacuum coating chamber, 35 is the nickel target, and 36 is the magnetron sputtering source. 37 Vacuum pump unit, 38 Inert gas supply system, 39 Uncoiler, 40 Pinch roll, 41 Inlet looper, 42 Degreasing and cleaning unit, 43 Electrolytic cleaning unit, 44 Hot water rinsing unit, 45 Hot air drying unit, 46 Continuous annealing furnace, 47 Heating zone, 48 Soaking zone, 49 Slow cooling zone, 50 Fast cooling zone, 51 Submerged roll, 52 Stabilizing roll, 53 Alloying heating furnace, 54 Post-plating cooling unit, 55 Finishing machine, 56 Passivation coating unit, 57 Atomizing cooling sprayer, 58 Cooling water circulation system, 59 Compressed air supply system, 60 Cooling air knife, 61 Roller coater, 62 Passivation liquid circulation supply system, 63 Infrared drying oven, 64 Outlet looper, 65 Coiler, 66 Air knife support, 67 First pipe, 68 Zinc liquid return pipe, 69 Online detection unit for steel plate surface temperature field, 70 Infrared thermal imager, 71 Multi-source sensor fusion decision module. Detailed Implementation

[0032] The attached figure illustrates a specific embodiment of the present invention. This embodiment includes an inlet section 2, a pretreatment section 3, an annealing section 4, a galvanizing section 5, a post-treatment section 6, and an outlet section 7.

[0033] The inlet section 2 includes an uncoiler 39, a pinch roll 40, and an inlet looper 41; the pretreatment section 3 includes a degreasing and cleaning unit 42, an electrolytic cleaning unit 43, a hot water rinsing unit 44, and a hot air drying unit 45; the annealing section 4 includes a continuous annealing furnace 46, which is divided into a heating zone 47, a soaking zone 48, a slow cooling zone 49, and a fast cooling zone 50 along the running direction of the steel plate 1; the galvanizing section 5 includes a zinc pot 8, a submerged roll 51 set inside the zinc pot 8, a stabilizing roll 52 set above the zinc pot 8, an air knife assembly 9 set above the zinc pot 8, and a first X-ray thickness gauge 13 set downstream of the air knife assembly 9; the post-treatment section 6 includes a second X-ray thickness gauge 14, an alloying heating furnace 53, a post-plating cooling unit 54, a finishing machine 55, and a passivation coating unit 56; and the outlet section 7 includes an outlet looper 64 and a coiler 65.

[0034] The galvanizing section 5 is also equipped with an online zinc dross separation and recovery subsystem 10, which includes: The zinc liquid circulation pump 11 has its inlet connected to the bottom of the zinc pot 8 via the first pipe 67; The electromagnetic induction zinc dross separator 12 has its inlet connected to the outlet of the zinc liquid circulation pump 11. Inside it are multiple sets of electromagnetic induction coils 16 and ceramic filter screens 17 arranged alternately along the zinc liquid flow direction. When the electromagnetic induction coils 16 are energized, they generate a gradient magnetic field to drive the zinc dross particles suspended in the zinc liquid toward the ceramic filter screen 17. The zinc liquid return pipe 68 is connected at one end to the outlet of the electromagnetic induction zinc slag separator 12 and at the other end to the upper part of the zinc pot 8. A zinc dross collection container 18 is located at the bottom of the electromagnetic induction zinc dross separator 12 and is used to collect the separated zinc dross.

[0035] The first X-ray thickness gauge 13 is set between the air knife assembly 9 and the alloying heating furnace 53 to detect the initial zinc layer thickness of the steel plate 1 after galvanizing; the second X-ray thickness gauge 14 is set between the finishing machine 55 and the passivation coating unit 56 to detect the final zinc layer thickness of the finished galvanized steel plate.

[0036] The air knife assembly 9 includes an upper air knife 19 and a lower air knife 20 disposed on both sides of the steel plate 1. The upper air knife 19 and the lower air knife 20 are respectively mounted on the air knife bracket 66 via independent servo adjustment mechanisms 21. The servo adjustment mechanism 21 includes a servo motor 22, a lead screw and nut pair 23, and a linear guide rail 24, used to independently adjust the distance between the upper air knife 19 and the lower air knife 20 and the surface of the steel plate 1. The air inlet ends of the upper air knife 19 and the lower air knife 20 are respectively connected to independent air pressure regulating valves 25 and air flow meters 26.

[0037] An online detection unit 69 for the surface temperature field of a steel plate is installed at the outlet of the rapid cooling zone 50. The online detection unit 69 for the surface temperature field of a steel plate includes: multiple infrared thermal imagers 70 arranged at intervals along the width direction of the steel plate 1, and the detection field of each infrared thermal imager 70 covers the entire width direction of the steel plate 1; each infrared thermal imager 70 is connected to the central controller 15 for transmitting the detected temperature distribution data to the central controller 15.

[0038] The galvanizing section 5 is also provided with a pre-nickel plating unit 33, which is located between the annealing section 4 and the zinc pot 8. The pre-nickel plating unit 33 includes: a vacuum coating chamber 34 through which the steel plate 1 passes; at least one set of nickel targets 35 and magnetron sputtering sources 36 installed in the vacuum coating chamber 34; a vacuum pump group 37 and an inert gas supply system 38 connected to the vacuum coating chamber 34.

[0039] An online surface cleanliness detection unit 27 is provided between the pretreatment section 3 and the annealing section 4. The online surface cleanliness detection unit 27 includes: an ultraviolet fluorescence excitation light source 28 disposed on one side of the steel plate 1; an ultraviolet fluorescence detection camera 29 disposed on the other side of the steel plate 1; and the ultraviolet fluorescence detection camera 29 is connected to the central controller 15.

[0040] The central controller 15 is connected to the actuators and detection units of the inlet section 2, pretreatment section 3, annealing section 4, galvanizing section 5, post-treatment section 6, and outlet section 7. The central controller 15 has a built-in multi-source sensor fusion decision module 71, which is configured to: receive real-time detection data from the first X-ray thickness gauge 13, the second X-ray thickness gauge 14, the online detection unit 69 for the steel plate surface temperature field, and the online detection unit 27 for surface cleanliness; and, based on the received real-time detection data, coordinately adjust at least the servo adjustment mechanism 21 of the air knife assembly 9, the air pressure regulating valve 25, the heating power of the annealing section 4, the temperature of the zinc pot 8, and the rotation speed of the zinc liquid circulation pump 11.

[0041] The bottom of the zinc pot 8 is equipped with a gradient heating device 30. The gradient heating device 30 includes multiple independently temperature-controlled induction heating coils 31 arranged at intervals along the width of the zinc pot 8. Each induction heating coil 31 is connected to an independent power supply module 32 to independently adjust the temperature of the zinc liquid in different width areas of the zinc pot 8.

[0042] The post-plating cooling unit 54 includes: atomizing cooling sprayers 57 disposed on both sides of the steel plate 1; a cooling water circulation system 58 and a compressed air supply system 59 connected to the atomizing cooling sprayers 57; and a cooling air knife 60 disposed behind the atomizing cooling sprayers 57.

[0043] The passivation coating unit 56 includes: a roller coater 61 with a microporous structure on its surface for uniformly coating the passivation liquid onto the surface of the steel plate 1; a passivation liquid circulation supply system 62 connected to the roller coater 61; and an infrared drying oven 63 located behind the roller coater 61.

[0044] The hot-dip galvanizing processing apparatus for steel plates of the present invention operates as follows: Cold-rolled steel plate 1 is uncoiled by uncoiler 39 and continuously fed into pretreatment section 3 via pinch rollers 40 and inlet looper 41. Steel plate 1 undergoes surface pretreatment sequentially through degreasing and cleaning unit 42, electrolytic cleaning unit 43, hot water rinsing unit 44, and hot air drying unit 45 to remove contaminants such as rolling oil and iron powder from its surface. The surface cleanliness online detection unit 27 irradiates the surface of steel plate 1 with ultraviolet fluorescence excitation light source 28, and the ultraviolet fluorescence detection camera 29 detects the fluorescence intensity of the steel plate 1 surface and transmits the cleanliness data to the central controller 15.

[0045] The pretreated steel plate 1 enters the continuous annealing furnace 46 and undergoes annealing treatment in sequence through the heating zone 47, the soaking zone 48, the slow cooling zone 49, and the rapid cooling zone 50. The infrared thermal imager 70 of the online temperature field detection unit 69 on the steel plate surface detects the temperature distribution in the width direction of the steel plate 1 in real time and transmits the temperature data to the central controller 15.

[0046] After annealing, the steel plate 1 enters the vacuum coating 34 of the pre-nickel plating unit 33. The vacuum pump group 37 evacuates the vacuum coating chamber 34 to a vacuum state, and the inert gas supply system 38 introduces argon gas. The magnetron sputtering source 36 excites the nickel target 35 to generate nickel ions and deposits them on the surface of the steel plate 1 to form a nickel pre-plating layer with a thickness of 0.1 to 0.3 μm.

[0047] The steel plate 1, after being pre-nickel-plated, is guided by the submersion roller 51 into the molten zinc in the zinc pot 8 for hot-dip galvanizing. The gradient heating device 30 at the bottom of the zinc pot 8 independently adjusts the temperature of the zinc liquid in each width area through each induction heating coil 31 to ensure uniform zinc liquid temperature.

[0048] The galvanized steel plate 1 is drawn out from the zinc pot 8, stabilized by the stabilizing roller 52, and then enters the air knife assembly 9 area. The first X-ray thickness gauge 13 detects the initial zinc layer thickness in real time and transmits the data to the central controller 15. Based on the deviation between the initial zinc layer thickness and the target thickness, the central controller 15 independently adjusts the distance between the upper air knife 19 and the lower air knife 20 and the surface of the steel plate 1 through the servo adjustment mechanism 21, and simultaneously adjusts the air pressure of each air knife through the air pressure regulating valve 25, thereby achieving closed-loop control of the coating thickness.

[0049] After being scraped by an air knife, the steel plate 1 enters the alloying heating furnace 53 for alloying treatment, and then is cooled by the post-plating cooling unit 54. The atomizing cooling sprayer 57 atomizes and cools the steel plate 1 under the action of the cooling water circulation system 58 and the compressed air supply system 59, and the cooling air knife 60 blows and dries the surface of the steel plate 1.

[0050] After cooling, the steel plate 1 is polished by the polishing machine 55. The second X-ray thickness gauge 14 detects the final zinc layer thickness, and the central controller 15 corrects the air knife parameters based on the final zinc layer thickness data.

[0051] After finishing, the steel plate 1 is passivated by the passivation coating unit 56. The passivation liquid provided by the passivation liquid circulation supply system 62 is uniformly coated on the surface of the steel plate 1 by the roller coating machine 61. The coated steel plate 1 is dried and cured by the infrared drying oven 63. Finally, the finished product is wound up by the exit looper 64 and the coiler 65.

[0052] During the galvanizing process, the zinc liquid circulation pump 11 continuously draws out the zinc liquid from the bottom of the zinc pot 8 and sends it to the electromagnetic induction zinc dross separator 12. The electromagnetic induction coil 16 is energized to generate a gradient magnetic field. Under the action of the magnetic field force, the zinc dross particles in the zinc liquid migrate towards the ceramic filter screen 17 and are intercepted. The purified zinc liquid returns to the zinc pot 8 through the zinc liquid return pipe 68, and the separated zinc dross falls into the zinc dross collection container 18.

[0053] The multi-source sensor fusion decision module 71 of the central controller 15 receives real-time data from the first X-ray thickness gauge 13, the second X-ray thickness gauge 14, the online detection unit 69 of the steel plate surface temperature field, and the online detection unit 27 of the surface cleanliness. Through the built-in data fusion algorithm and decision tree control model, it comprehensively judges the current galvanizing state and accordingly adjusts the servo adjustment mechanism 21 of the air knife assembly 19, the air pressure regulating valve 25, the heating power of the annealing section 4, the temperature of the zinc pot 8, and the speed of the zinc liquid circulation pump 11.

[0054] The hot-dip galvanizing processing device for steel plates of the present invention integrates electromagnetic induction zinc dross online separation into a continuous hot-dip galvanizing production line. By setting up an electromagnetic induction zinc dross separator, the gradient magnetic field is used to realize the online continuous separation and recycling of zinc dross, realizing the leap from offline batch processing to online continuous processing of zinc dross removal.

[0055] A multi-source sensor fusion system consisting of dual X-ray thickness gauges, multiple infrared thermal imagers, and ultraviolet fluorescence detection was constructed. The first X-ray thickness gauge enables feedforward control of the initial thickness after plating, the second X-ray thickness gauge enables feedback control of the final thickness of the finished product, the infrared thermal imagers enable real-time monitoring of temperature distribution, and the ultraviolet fluorescence detection camera enables online assessment of cleanliness. The four components are integrated to form a complete closed-loop control link.

[0056] Introducing pre-plated nickel into a continuous hot-dip galvanizing production line solves the problem of plating applicability of high-strength steel. By integrating it with the continuous hot-dip galvanizing process, a nickel pre-plating layer is deposited after annealing and before galvanizing through magnetron sputtering, which fundamentally solves the problem of deterioration in plating applicability caused by selective oxidation of high-strength steel.

[0057] It has realized the transformation of control mode from single-point control to global coordination. Through the multi-source sensor fusion decision module of the central controller, it has realized the coordinated linkage control of each link of pretreatment, annealing, galvanizing and post-treatment.

Claims

1. A hot-dip galvanizing processing apparatus for steel plates, comprising an inlet section (2), a pretreatment section (3), an annealing section (4), a galvanizing section (5), a post-treatment section (6), and an outlet section (7) arranged sequentially along the running direction of the steel plate (1), wherein the galvanizing section (5) includes a zinc pot (8), and an air knife assembly (9) is provided above the zinc pot (8), characterized in that: The galvanizing section (5) is equipped with an online zinc slag separation and recovery subsystem (10). The online zinc slag separation and recovery subsystem (10) includes a zinc liquid circulation pump (11) connected to the bottom of the zinc pot (8). The outlet of the zinc liquid circulation pump (11) is connected to the inlet of the electromagnetic induction zinc slag separator (12). The outlet of the electromagnetic induction zinc slag separator (12) is connected to the upper part of the zinc pot (8). The galvanizing section (5) is equipped with a first X-ray thickness gauge (13), and the post-processing section (6) is equipped with a second X-ray thickness gauge (14). Both the first X-ray thickness gauge (13) and the second X-ray thickness gauge (14) are connected to the central controller (15).

2. The steel plate hot-dip galvanizing processing apparatus according to claim 1, characterized in that: The electromagnetic induction zinc slag separator (12) is equipped with multiple sets of electromagnetic induction coils (16) and ceramic filter screens (17) arranged alternately along the direction of zinc liquid flow. A zinc slag collection container (18) is provided below the electromagnetic induction zinc slag separator (12).

3. The hot-dip galvanizing apparatus for steel plates according to claim 1, characterized in that: The air knife assembly (9) includes an upper air knife (19) and a lower air knife (20). The upper air knife (19) and the lower air knife (20) are respectively mounted on the air knife bracket (66) through a servo adjustment mechanism (21). The servo adjustment mechanism (21) includes a servo motor (22). A lead screw and nut pair (23) is mounted on the servo motor (22). The lead screw and nut pair (23) is connected to the upper air knife (19) or the lower air knife (20). The lead screw and nut pair (23) moves linearly along the guide rail (24).

4. The hot-dip galvanizing apparatus for steel plates according to claim 3, characterized in that: The air inlet ends of the upper air knife (19) and the lower air knife (20) are respectively connected to an air pressure regulating valve (25) and an air flow meter (26).

5. The hot-dip galvanizing apparatus for steel plates according to claim 1, characterized in that: A surface cleanliness online detection unit (27) is provided between the pretreatment section (3) and the annealing section (4). The surface cleanliness online detection unit (27) includes an ultraviolet fluorescence excitation light source (28) and an ultraviolet fluorescence detection camera (29) located on both sides of the steel plate (1).

6. The hot-dip galvanizing apparatus for steel plates according to claim 1, characterized in that: The bottom of the zinc pot (8) is provided with a gradient heating device (30), which includes multiple independently temperature-controlled induction heating coils (31) arranged at intervals along the width direction of the zinc pot (8). Each induction heating coil (31) is connected to an independent power supply module (32).

7. The steel plate hot-dip galvanizing processing apparatus according to claim 1, characterized in that: A pre-nickel plating unit (33) is provided between the annealing section (4) and the zinc pot (8). The pre-nickel plating unit (33) includes a vacuum plating chamber (34). The vacuum plating chamber (34) is provided with several sets of nickel targets (35) and magnetron sputtering sources (36). The vacuum plating chamber (34) is connected to a vacuum pump group (37) and an inert gas supply system (38).

8. The hot-dip galvanizing apparatus for steel plates according to claim 1, characterized in that: The inlet section (2) includes an uncoiler (39), a pinch roll (40), and an inlet looper (41); the pretreatment section (3) includes a degreasing and cleaning unit (42), an electrolytic cleaning unit (43), a hot water rinsing unit (44), and a hot air drying unit (45); the annealing section (4) includes a continuous annealing furnace (46), which is divided into a heating zone (47), a homogenizing zone (48), a slow cooling zone (49), and a fast cooling zone (50) along the running direction of the steel plate (1); a submerged roller (51) is provided in the zinc pot (8), and a stabilizing roller (52) is provided above the submerged roller (51).

9. The hot-dip galvanizing apparatus for steel plates according to claim 1, characterized in that: The post-processing section (6) includes an alloying heating furnace (53), a post-plating cooling unit (54), a finishing machine (55), and a passivation coating unit (56). The post-plating cooling unit (54) includes atomizing cooling sprayers (57) located on both sides of the steel plate (1). The atomizing cooling sprayers (57) are connected to a cooling water circulation system (58) and a compressed air supply system (59). A cooling air knife (60) is provided behind the atomizing cooling sprayers (57). The passivation coating unit (56) includes a roller coater (61). The roller coater (61) is connected to a passivation liquid circulation supply system (62). An infrared drying oven (63) is provided behind the roller coater (61).

10. The steel plate hot-dip galvanizing processing apparatus according to claim 1, characterized in that: The exit section (7) includes an exit looper (64) and a winding machine (65).

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