Method and equipment for hot galvanizing of hot-rolled thin steel strip

Abstract

The invention provides a method and equipment for hot galvanizing of a hot-rolled thin steel strip, and relates to the field of hot galvanizing of steel strips, the equipment comprises an inlet sealing section, a heating section, a uniform heating section, a cooling section, a material guiding section and a galvanizing box which are arranged in sequence, and further comprises a zinc liquid circulating unit, a first waste heat utilization unit and a second waste heat utilization unit; a medium-frequency transverse magnetic field combined heating unit is arranged in the heating section, and a medium-frequency longitudinal magnetic field heating unit is arranged in the uniform heating section; a first air knife and a cooling roller set are arranged in the cooling section, a guide-in roller, a guide-out roller and a second air knife are arranged in the material guiding section, an immersion roller, a first turning roller, a stabilizing roller and a second turning roller are arranged in the galvanizing box, the first waste heat utilization unit comprises a first heat exchanger, and the second waste heat utilization unit comprises a second heat exchanger. The waste heat utilization efficiency in the whole galvanization process is improved, molten zinc in the galvanization box is circularly heated and filtered, it is guaranteed that the temperature in the galvanization box is stable, the influence of particles on the molten zinc is reduced, and then the steel strip galvanization quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hot-dip galvanizing of packaging steel strips, and in particular to a method and equipment for hot-dip galvanizing of hot-rolled thin-gauge steel strips. Background Art

[0002] Thin-gauge steel strip generally refers to coiled strip steel with a thickness of 0.1-4 mm, which is mainly produced by thin slab continuous casting and rolling process.

[0003] The continuous hot-dip galvanizing process for hot-rolled strip steel is to directly put the hot-rolled strip steel into the reduction furnace after pickling, reduce the iron oxide on the surface of the strip steel in the reduction furnace, and then cool it to the required temperature for galvanizing, and then enter the galvanizing pool for galvanizing. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life. The hot-rolled strip steel after galvanizing has stronger corrosion resistance, weather resistance and higher mechanical properties. The continuous hot-dip galvanizing equipment for hot-rolled strip steel is an important device for hot-dip galvanizing hot-rolled strip steel.

[0004] Existing reduction furnaces are usually heated by gas radiation tubes. The combustion of gas will produce flue gas containing a large amount of nitrogen oxides and particles, which will be discharged into the atmosphere and pollute the surrounding environment. Heat dissipation and cooling usually use fans and water cooling, and the cooling efficiency is low. During the galvanizing process, impurities in the galvanizing pool need to be manually cleaned, which is labor-intensive and has low waste heat utilization efficiency during the entire galvanizing process. Summary of the invention

[0005] The object of the present invention is to provide a method and equipment for hot-dip galvanizing of hot-rolled thin-gauge steel strips to solve the problems raised in the above-mentioned background technology.

[0006] On the one hand, the present invention provides a hot-dip galvanizing equipment for hot-rolled thin-gauge steel strips, comprising an inlet sealing section, a heating section, a uniform heating section, a cooling section, a material guiding section, and a galvanizing box which are arranged in sequence;

[0007] A medium frequency transverse magnetic field combined heating unit is provided inside the heating section, and the magnetic field direction generated by the medium frequency transverse magnetic field combined heating unit is perpendicular to the surface of the steel strip. A hydrogen inlet interface is provided on the feeding side of the heating section, and a hydrogen outlet interface is provided on the discharging side. The hydrogen inlet interface is connected to an external hydrogen gas source.

[0008] A medium frequency longitudinal magnetic field heating unit is provided inside the uniform heating section, and the magnetic field direction generated by the medium frequency longitudinal magnetic field heating unit is parallel to the surface of the steel strip;

[0009] A first air knife is arranged inside the cooling section, and two first air knives are arranged symmetrically up and down;

[0010] The guide section is provided with an inlet roller, an outlet roller, and a second air knife, and the two second air knives are symmetrically arranged on the left and right. The second air knife is located below the outlet roller, and an outlet sealing section is provided on the outlet side of the guide section; the first air knife and the second air knife are both connected to an external nitrogen gas source;

[0011] The galvanizing box is provided with an immersion roller, a first steering roller, a stabilizing roller, and a second steering roller. The immersion roller is located below the introduction roller, and the immersion roller and the first steering roller are arranged at the same height. The stabilizing roller is located above the first steering roller, and the second steering roller is located below the lead-out roller. The steel strip passes through the lead-in roller, the immersion roller, the first steering roller, the stabilizing roller, the second steering roller, and the lead-out roller in sequence. A nitrogen outlet interface is provided on the upper part of one side of the galvanizing box.

[0012] Furthermore, the medium frequency transverse magnetic field combined heating unit comprises a plurality of first transverse magnetic field heaters and second transverse magnetic field heaters which are alternately arranged;

[0013] The first transverse magnetic field heater is used to heat the central part of the steel strip, and includes an induction heating coil a and an induction heating coil b symmetrically arranged on the upper and lower sides of the steel strip, wherein a plurality of induction coils a are arranged side by side at equal intervals along the width direction of the steel strip, and a plurality of induction coils b are arranged side by side at equal intervals along the width direction of the steel strip;

[0014] The second transverse magnetic field heater is used to heat the edge of the steel strip, and includes an induction heating coil c and an induction heating coil d symmetrically arranged on the upper and lower sides of the steel strip. The two induction coils c are respectively arranged above the two edge parts of the steel strip, and the two induction heating coils d are respectively arranged below the two edge parts of the steel strip.

[0015] Furthermore, the medium frequency longitudinal magnetic field heating unit includes a longitudinal magnetic field heater, and the longitudinal magnetic field heater includes a plurality of induction heating coils e arranged at equal intervals along the running direction of the steel strip.

[0016] Furthermore, the induction heating coil a, the induction heating coil b, the induction heating coil c, the induction heating coil d, and the induction heating coil e are all rectangular coils.

[0017] Furthermore, an insulation board a is provided between the induction heating coil a, the induction heating coil c and the steel strip, an insulation board b is provided between the induction heating coil b, the induction heating coil d and the steel strip; an insulation board c is provided between the induction heating coil e and the steel strip, and the cross-section of the insulation board c is rectangular.

[0018] Furthermore, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a zinc liquid circulation unit, which includes a zinc storage box, a circulation pump, and a filter box. The zinc storage box is connected to the liquid inlet pipe of the galvanizing box through the circulation pump, the liquid outlet pipe of the galvanizing box is connected to the filter box, the filter box is connected to the zinc storage box through a pipeline, and an electric heating plate is arranged on the side wall of the zinc storage box.

[0019] Furthermore, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a first waste heat utilization unit, which includes a first heat exchanger, a first cold side inlet provided on the first heat exchanger is connected to a hydrogen gas source, a first cold side outlet provided on the first heat exchanger is connected to a hydrogen inlet interface, a second cold side inlet provided on the first heat exchanger is connected to a nitrogen gas source, a second cold side outlet provided on the first heat exchanger is respectively connected to the air inlets of the first air knife and the second air knife, a hot side inlet provided on the first heat exchanger is connected to a liquid outlet pipe of the galvanizing box, and a hot side outlet provided on the first heat exchanger is connected to a filter box.

[0020] Furthermore, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a second waste heat utilization unit, which includes a second heat exchanger, a cold medium inlet arranged on the second heat exchanger is connected to the liquid outlet of the filter box, a cold medium outlet arranged on the second heat exchanger is connected to the zinc storage box, a hot medium inlet on the second heat exchanger is connected to the hydrogen outlet interface, and a hot medium outlet on the second heat exchanger is connected to the waste hydrogen recovery pipe.

[0021] Furthermore, a cooling roller group is provided in the cooling section, and two cooling roller groups are symmetrically arranged up and down, the liquid inlet end of the cooling roller group is connected to the liquid outlet end of the filter box, and the liquid outlet end of the cooling roller group is connected to the cold side inlet on the second heat exchanger.

[0022] On the other hand, the present invention provides a method for hot-dip galvanizing a hot-rolled thin-gauge steel strip, using the above-mentioned hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip, comprising:

[0023] (1) After pickling, the hot-rolled thin-gauge steel strip enters the heating section and the uniform heating section through the inlet sealing section for induction heating, wherein the hot-rolled thin-gauge steel strip is heated in the reducing atmosphere of the heating section until the thin layer of iron oxide on the surface is fully reduced;

[0024] (2) The hot-rolled thin-gauge steel strip enters the cooling section, is cooled by the cooling roller group and the first air knife, and then enters the guide section. It then moves downward into the galvanizing box in a nitrogen atmosphere for continuous reversing galvanizing.

[0025] (3) After galvanizing, the hot-rolled thin-gauge steel enters the guide section from the galvanizing box upwards, and is wiped by the second air knife to adjust the thickness of the coating and dried before being led out from the outlet sealing section.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention adopts a medium frequency transverse magnetic field combined heating unit and a medium frequency longitudinal magnetic field heating unit to perform induction heating and uniform heat treatment on the steel strip, which can quickly and efficiently heat the steel strip to above 500°C and ensure heating uniformity.

[0028] 2. The present invention adopts a first waste heat utilization unit, a second waste heat utilization unit and a zinc liquid circulation unit to improve the waste heat utilization efficiency of the entire galvanizing process. The zinc liquid in the galvanizing box is circulated, heated and filtered to ensure the temperature stability in the galvanizing box and reduce the influence of particulate matter on the zinc liquid, thereby improving the galvanizing quality of the steel strip. The zinc liquid preheats nitrogen and hydrogen through the first heat exchanger to reduce the influence of exogenous low-temperature nitrogen and hydrogen entering the equipment on the temperature of the steel strip. The high-temperature hydrogen drawn out from the heating section heats the circulating zinc liquid through the second heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the middle heating section;

[0031] Figure 3 It is a three-dimensional diagram of the inlet sealing section, heating section and uniform heating section;

[0032] Figure 4 It is a three-dimensional picture of a galvanized box;

[0033] Figure 5 is a three-dimensional diagram of a first heat exchanger;

[0034] Figure numerals: 1-entrance sealing section, 2-heating section, 201-first transverse magnetic field heater, 2011-induction heating coil a, 2012-induction heating coil b, 202-second transverse magnetic field heater, 2021-induction heating coil c, 2022-induction heating coil d, 203-heating plate a, 204-heating plate b, 205-hydrogen inlet interface, 206-hydrogen outlet interface, 301-induction heating coil e, 302-heating plate c, 3-uniform heating section, 4-cooling section, 401-cooling roller group, 402-first air knife, 5-material guiding section, 501-introduction roller, 502-guide Outlet roller, 503-second air knife, 6-galvanizing box, 601-immersion roller, 602-first turning roller, 603-stabilizing roller, 604-second turning roller, 605-nitrogen outlet interface, 7-outlet sealing section, 8-hydrogen gas source, 9-nitrogen gas source, 10-first heat exchanger, 1001-first cold side inlet, 1002-first cold side outlet, 1003-second cold side inlet, 1004-second cold side outlet, 1005-hot side inlet, 1006-hot side outlet, 11-zinc storage box, 1101-electric heating plate, 12-circulating pump, 13-second heat exchanger, 14-filter box, 15-steel belt. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] Please see attached Figure 1-5 As shown, a hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip 15 comprises an inlet sealing section 1, a heating section 2, a uniform heating section 3, a cooling section 4, a material guiding section 5, and a galvanizing box 6 which are arranged in sequence;

[0037] A medium frequency transverse magnetic field combined heating unit is provided inside the heating section 2. The magnetic field direction generated by the medium frequency transverse magnetic field combined heating unit is perpendicular to the surface of the steel strip 15. A hydrogen inlet interface 205 is provided on the feeding side of the heating section 2, and a hydrogen outlet interface 206 is provided on the discharging side. The hydrogen inlet interface 205 is connected to an external hydrogen gas source 8.

[0038] A medium frequency longitudinal magnetic field heating unit is provided inside the uniform heating section 3, and the magnetic field direction generated by the medium frequency longitudinal magnetic field heating unit is parallel to the surface of the steel strip 15;

[0039] A first air knife 402 is arranged inside the cooling section 4, and two first air knives 402 are arranged symmetrically up and down;

[0040] The guide section 5 is provided with an introduction roller 501, an outlet roller 502, and a second air knife 503. The two second air knives 503 are symmetrically arranged on the left and right. The second air knives 503 are located below the outlet roller 502. An outlet sealing section 7 is provided on the outlet side of the guide section 5. The first air knife 402 and the second air knife 503 are both connected to an external nitrogen gas source 9.

[0041] The galvanizing box 6 is provided with an immersion roller 601, a first steering roller 602, a stabilizing roller 603, and a second steering roller 604. The immersion roller 601 is located below the introduction roller 501. The immersion roller 601 and the first steering roller 602 are arranged at the same height. The stabilizing roller 603 is located above the first steering roller 602. The second steering roller 604 is located below the lead-out roller 502. The steel strip 15 passes through the lead-in roller 501, the immersion roller 601, the first steering roller 602, the stabilizing roller 603, the second steering roller 604, and the lead-out roller 502 in sequence. A nitrogen outlet interface 605 is provided on the upper part of one side of the galvanizing box 6.

[0042] Specifically, the medium-frequency transverse magnetic field combined heating unit includes a plurality of alternately arranged first transverse magnetic field heaters 201 and second transverse magnetic field heaters 202; the first transverse magnetic field heater 201 is used to heat the central part of the steel strip 15, and includes an induction heating coil a2011 and an induction heating coil b2012 symmetrically arranged on the upper and lower sides of the steel strip 15, and a plurality of induction coils a are arranged side by side at equal intervals along the width direction of the steel strip 15, and a plurality of induction coils b are arranged side by side at equal intervals along the width direction of the steel strip 15; the second transverse magnetic field heater 202 is used to heat the edge part of the steel strip 15, and includes an induction heating coil c2021 and an induction heating coil d2022 symmetrically arranged on the upper and lower sides of the steel strip 15, two induction coils c are respectively arranged above the two edge parts of the steel strip 15, and two induction heating coils d2022 are respectively arranged below the two edge parts of the steel strip 15; the medium-frequency longitudinal magnetic field heating unit includes a longitudinal magnetic field heater, and the longitudinal magnetic field heater includes a plurality of induction heating coils e301 arranged at equal intervals along the running direction of the steel strip 15.

[0043] In this embodiment, the medium frequency transverse magnetic field combined heating unit is used to quickly heat and raise the temperature of the steel strip 15, and the medium frequency longitudinal magnetic field heating unit is used to fine-tune and keep the temperature of the steel strip 15 warm, so as to ensure the temperature uniformity in the width direction of the steel strip 15 during the heat treatment of the steel strip 15. The induction heating coil a2011, the induction heating coil b2012, the induction heating coil c2021, the induction heating coil d2022, and the induction heating coil e301 are all rectangular coils; a heat insulation board a203 is provided between the induction heating coil a2011, the induction heating coil c2021 and the steel strip 15, and a heat insulation board b204 is provided between the induction heating coil b2012, the induction heating coil d2022 and the steel strip 15; a heat insulation board c302 is provided between the induction heating coil e301 and the steel strip 15, and the cross section of the heat insulation board c302 is rectangular.

[0044] In this embodiment, the electrical parameters of each induction heating coil can be independently controlled, and appropriate heating frequency and power are applied during heating. A temperature sensor is correspondingly arranged on the rear side of each induction heating coil to facilitate flexible and timely adjustment of the electrical parameters of each induction heating coil to ensure uniformity of heating temperature and high heating efficiency.

[0045] As one of the embodiments of the present invention, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip 15 of the present invention further includes a zinc liquid circulation unit, which includes a zinc storage box 11, a circulation pump 12, and a filter box 14. The zinc storage box 11 is connected to the liquid inlet pipe of the galvanizing box 6 through the circulation pump 12, and the liquid outlet pipe of the galvanizing box 6 is connected to the filter box 14. The filter box 14 is connected to the zinc storage box 11 through a pipeline, and an electric heating plate 1101 is arranged on the side wall of the zinc storage box 11. The zinc liquid in the galvanizing box 6 is circulated, heated, and filtered to ensure the temperature stability in the galvanizing box 6 and reduce the influence of particulate matter on the zinc liquid, thereby improving the galvanizing quality of the steel strip 15.

[0046] As one of the embodiments of the present invention, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip 15 of the present invention further includes a first waste heat utilization unit, which includes a first heat exchanger 10, a first cold side inlet 1001 provided on the first heat exchanger 10 is connected to a hydrogen gas source 8, a first cold side outlet 1002 provided on the first heat exchanger 10 is connected to a hydrogen gas inlet interface 205, a second cold side inlet 1003 provided on the first heat exchanger 10 is connected to a nitrogen gas source 9, a second cold side outlet 1004 provided on the first heat exchanger 10 is respectively connected to the gas inlets of the first air knife 402 and the second air knife 503, a hot side inlet 1005 provided on the first heat exchanger 10 is connected to a liquid outlet pipe of a galvanizing box 6, and a hot side outlet 1006 provided on the first heat exchanger 10 is connected to a filter box 14. The zinc liquid preheats nitrogen and hydrogen through the first heat exchanger 10 to reduce the influence of exogenous low-temperature nitrogen and hydrogen entering the equipment on the temperature of the steel strip 15.

[0047] In this embodiment, the hot side outlet 1006 is located between the first cold side inlet 1001 and the second cold side inlet 1003 , and the hot side inlet 1005 is located between the first cold side outlet 1002 and the second cold side outlet 1004 .

[0048] As one of the embodiments of the present invention, the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip 15 of the present invention further includes a second waste heat utilization unit, which includes a second heat exchanger 13, a cold medium inlet provided on the second heat exchanger 13 is connected to the liquid outlet of the filter box 14, a cold medium outlet provided on the second heat exchanger 13 is connected to the zinc storage box 11, a hot medium inlet on the second heat exchanger 13 is connected to the hydrogen outlet interface 206, and a hot medium outlet on the second heat exchanger 13 is connected to a waste hydrogen recovery pipe. The high-temperature hydrogen drawn out from the heating section 2 heats the circulating zinc liquid through the second heat exchanger 13, and the waste hydrogen is collected through the waste hydrogen recovery pipe for recycling.

[0049] As one of the embodiments of the present invention, a cooling roller group 401 is further provided in the cooling section 4 of the hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip 15 of the present invention. Two groups of cooling roller groups 401 are symmetrically arranged up and down, and the liquid inlet end of the cooling roller group 401 is connected to the liquid outlet end of the filter box 14, and the liquid outlet end of the cooling roller group 401 is connected to the cold side inlet on the second heat exchanger 13. The zinc liquid flowing out of the first heat exchanger 10 enters the cooling roller group 401 after being filtered to cool the steel strip 15.

[0050] Based on the above hot-rolled thin-gauge steel strip 15 hot-dip galvanizing equipment, the present invention also provides a method for hot-rolled thin-gauge steel strip 15 hot-dip galvanizing, comprising:

[0051] (1) After pickling, the hot-rolled thin-gauge steel strip 15 enters the heating section 2 and the uniform heating section 3 through the inlet sealing section 1 for induction heating, wherein the hot-rolled thin-gauge steel strip 15 is heated in the reducing atmosphere of the heating section 2 until the thin layer of iron oxide on the surface is fully reduced;

[0052] (2) The hot-rolled thin-gauge steel strip 15 enters the cooling section 4, is cooled by the cooling roller group 401 and the first air knife 402, and then enters the guide section 5, and then enters the galvanizing box 6 in the nitrogen atmosphere for continuous reversing galvanizing;

[0053] (3) After galvanizing, the hot-rolled thin-gauge steel enters the guide section 5 upward from the galvanizing box 6, and is wiped and dried by the second air knife 503 to adjust the thickness of the coating, and then is led out from the outlet sealing section 7.

[0054] Specifically, the hot-rolled thin-gauge steel strip 15 is heat treated to 540-560° C. in the heating section 2 and the uniform heating section 3, and is cooled to 460-470° C. in the cooling section 4. The temperature of the zinc liquid in the galvanizing box 6 is 460-470° C., and the running speed of the steel strip 15 is 10-50 m / min.

Claims

1. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strips, comprising an inlet sealing section, a heating section, a uniform heating section, a cooling section, a material guiding section, and a galvanizing box arranged in sequence, characterized in that: A medium frequency transverse magnetic field combined heating unit is provided inside the heating section, and the magnetic field direction generated by the medium frequency transverse magnetic field combined heating unit is perpendicular to the surface of the steel strip. A hydrogen inlet interface is provided on the feeding side of the heating section, and a hydrogen outlet interface is provided on the discharging side. The hydrogen inlet interface is connected to an external hydrogen gas source. A medium frequency longitudinal magnetic field heating unit is provided inside the uniform heating section, and the magnetic field direction generated by the medium frequency longitudinal magnetic field heating unit is parallel to the surface of the steel strip; A first air knife is arranged inside the cooling section, and two first air knives are arranged symmetrically up and down; The guide section is provided with an inlet roller, an outlet roller, and a second air knife, and the two second air knives are symmetrically arranged on the left and right. The second air knife is located below the outlet roller, and an outlet sealing section is provided on the outlet side of the guide section; the first air knife and the second air knife are both connected to an external nitrogen gas source; The galvanizing box is provided with an immersion roller, a first steering roller, a stabilizing roller, and a second steering roller. The immersion roller is located below the introduction roller, and the immersion roller and the first steering roller are arranged at the same height. The stabilizing roller is located above the first steering roller, and the second steering roller is located below the lead-out roller. The steel strip passes through the lead-in roller, the immersion roller, the first steering roller, the stabilizing roller, the second steering roller, and the lead-out roller in sequence. A nitrogen outlet interface is provided on the upper part of one side of the galvanizing box.

2. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 1, characterized in that: The intermediate frequency transverse magnetic field combined heating unit comprises a plurality of first transverse magnetic field heaters and second transverse magnetic field heaters which are arranged alternately; The first transverse magnetic field heater is used to heat the central part of the steel strip, and includes an induction heating coil a and an induction heating coil b symmetrically arranged on the upper and lower sides of the steel strip, wherein a plurality of induction coils a are arranged side by side at equal intervals along the width direction of the steel strip, and a plurality of induction coils b are arranged side by side at equal intervals along the width direction of the steel strip; The second transverse magnetic field heater is used to heat the edge of the steel strip, and includes an induction heating coil c and an induction heating coil d symmetrically arranged on the upper and lower sides of the steel strip. The two induction coils c are respectively arranged above the two edge parts of the steel strip, and the two induction heating coils d are respectively arranged below the two edge parts of the steel strip.

3. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 2, characterized in that: The medium frequency longitudinal magnetic field heating unit comprises a longitudinal magnetic field heater, and the longitudinal magnetic field heater comprises a plurality of induction heating coils e arranged at equal intervals along the running direction of the steel strip.

4. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 3, characterized in that: The induction heating coil a, the induction heating coil b, the induction heating coil c, the induction heating coil d and the induction heating coil e are all rectangular coils.

5. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 4, characterized in that: An insulation board a is provided between the induction heating coil a, the induction heating coil c and the steel strip, an insulation board b is provided between the induction heating coil b, the induction heating coil d and the steel strip; an insulation board c is provided between the induction heating coil e and the steel strip, and the cross section of the insulation board c is rectangular.

6. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 1, characterized in that: The hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a zinc liquid circulation unit, which includes a zinc storage box, a circulation pump, and a filter box. The zinc storage box is connected to the liquid inlet pipe of the galvanizing box through the circulation pump, the liquid outlet pipe of the galvanizing box is connected to the filter box, the filter box is connected to the zinc storage box through a pipeline, and an electric heating plate is arranged on the side wall of the zinc storage box.

7. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 6, characterized in that: The hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a first waste heat utilization unit, which includes a first heat exchanger, a first cold side inlet provided on the first heat exchanger is connected to a hydrogen gas source, a first cold side outlet provided on the first heat exchanger is connected to a hydrogen inlet interface, a second cold side inlet provided on the first heat exchanger is connected to a nitrogen gas source, a second cold side outlet provided on the first heat exchanger is respectively connected to the air inlets of the first air knife and the second air knife, a hot side inlet provided on the first heat exchanger is connected to a liquid outlet pipe of a galvanizing box, and a hot side outlet provided on the first heat exchanger is connected to a filter box.

8. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 7, characterized in that: The hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip also includes a second waste heat utilization unit, which includes a second heat exchanger, a cold medium inlet arranged on the second heat exchanger is connected to the liquid outlet of the filter box, a cold medium outlet arranged on the second heat exchanger is connected to the zinc storage box, a hot medium inlet on the second heat exchanger is connected to the hydrogen outlet interface, and a hot medium outlet on the second heat exchanger is connected to the waste hydrogen recovery pipe.

9. A hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to claim 8, characterized in that: The cooling section is also provided with a cooling roller group, and the two cooling roller groups are symmetrically arranged up and down, the liquid inlet end of the cooling roller group is connected to the liquid outlet end of the filter box, and the liquid outlet end of the cooling roller group is connected to the cold side inlet on the second heat exchanger.

10. A method for hot-dip galvanizing of hot-rolled thin-gauge steel strip, characterized in that: The hot-dip galvanizing equipment for hot-rolled thin-gauge steel strip according to any one of claim 9 comprises: (1) After pickling, the hot-rolled thin-gauge steel strip enters the heating section and the uniform heating section through the inlet sealing section for induction heating, wherein the hot-rolled thin-gauge steel strip is heated in the reducing atmosphere of the heating section until the thin layer of iron oxide on the surface is fully reduced; (2) The hot-rolled thin-gauge steel strip enters the cooling section, is cooled by the cooling roller group and the first air knife, and then enters the guide section. It then moves downward into the galvanizing box in a nitrogen atmosphere for continuous reversing galvanizing. (3) After galvanizing, the hot-rolled thin-gauge steel enters the guide section from the galvanizing box upwards, and is wiped by the second air knife to adjust the thickness of the coating and dried before being led out from the outlet sealing section.

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