A method and device for adjusting the thickness of hot-dip galvanized coating

Abstract

The invention relates to the technical field of hot-dip galvanizing, and in particular to a method and device for adjusting the thickness of a hot-dip galvanizing coating. The method for adjusting the thickness of a hot-dip galvanizing coating comprises the following steps: an air knife body is arranged on one side of a steel strip to spray a first inert gas flow toward the surface of the steel strip, wherein the first inert gas flow is used to wipe the galvanized layer on the surface of the steel strip; a second inert gas flow and a third inert gas flow are respectively applied to the upper side and the lower side of the first inert gas flow, so that the second inert gas flow and the third inert gas flow flow to the upper end face and the lower end face of the first inert gas flow respectively, so that the second inert gas flow and the third inert gas flow fill the negative pressure areas on the upper and lower sides of the first inert gas flow, and a stable inert gas self-compensation is realized for the low pressure area formed around the first inert gas flow; the purity of the inert gas sprayed from the air knife body to the surface of the steel strip is improved, the amount of zinc slag formed due to oxidation is reduced, the quality of the coating on the surface of the steel strip is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hot-dip galvanizing, and in particular to a method and a device for adjusting the thickness of a hot-dip galvanizing coating. Background Art

[0002] During the continuous hot-dip coating process of steel strips, an air knife spray system is required to achieve precise control of the coating thickness on the steel strip surface. The air knife spray system includes an air knife lifting and lowering adjustment mechanism, an air knife quick opening and tilt angle adjustment device, a knife lip width and edge baffle adjustment mechanism, a spray medium supply and adjustment device, and a three-electric control system. The air knife nozzle is arranged opposite to the galvanized surface of the steel strip. The air knife nozzle is in the shape of a strip, and the length direction of the strip air knife nozzle is arranged along the width direction of the steel strip. The inert airflow ejected by the air knife nozzle is used to wipe the zinc layer applied to the steel strip from the zinc pot. The thickness control of the target coating is achieved by adjusting parameters such as the opening degree and airflow pressure of the air knife nozzle.

[0003] Adding magnesium and aluminum to hot-dip galvanizing liquid can improve the corrosion resistance and coating quality of the galvanized layer. However, due to the oxidizability order of magnesium>aluminum>zinc, it is easier to produce oxidized metal slag when the galvanized layer is sprayed with an air knife than with ordinary zinc liquid. After the metal slag splashes and adheres to the surface of the strip, it will cause quality defects in the coating on the strip surface.

[0004] After research, the inventor found that when the galvanized layer is sprayed by the air knife, the oxidation of the zinc liquid is due to the insufficient purity of the inert gas sprayed by the air knife to the surface of the strip. The main reason for the insufficient purity of the inert gas sprayed by the air knife to the surface of the strip is: the flow rate of the inert gas flow sprayed by the air knife nozzle is relatively high, so a negative pressure is formed around the inert gas flow, and the air above and below the inert gas flow will be accelerated to flow toward the inert gas flow under the action of the negative pressure, thereby increasing the amount of mixed air in the inert gas flow, which in turn leads to the insufficient purity of the inert gas sprayed by the air knife to the surface of the strip, resulting in oxidation of the zinc liquid.

[0005] In order to improve the coating quality of hot-dip galvanized layer, a hot-dip galvanized coating thickness adjustment device is urgently needed to reduce the purity of the inert gas sprayed by the air knife to the surface of the strip. Summary of the invention

[0006] The purpose of the present invention is to provide a method and device for adjusting the thickness of a hot-dip galvanized coating.

[0007] The method for adjusting the thickness of the hot-dip galvanized coating of the present invention comprises the following steps: an air knife body is arranged on one side of the steel strip to spray a first inert gas flow toward the surface of the steel strip, wherein the first inert gas flow is used to wipe the galvanized layer on the surface of the steel strip; a second inert gas flow and a third inert gas flow are applied to the upper side and the lower side of the first inert gas flow, respectively, so that the second inert gas flow and the third inert gas flow flow to the upper negative pressure zone and the lower negative pressure zone of the first inert gas flow, respectively.

[0008] The hot-dip galvanizing coating thickness adjustment device of the present invention comprises an air knife body for spraying a first inert gas flow toward a steel strip, an upper air supply hood is provided at the upper portion of the air knife body, a lower air supply hood is provided at the lower portion of the air knife body, the upper air supply hood is provided with a first air inlet and a first air outlet, the lower air supply hood is provided with a second air inlet and a second air outlet, the first air inlet and the second air inlet are both connected to a first inert gas source, the first air outlet is arranged toward the upper end surface of the first inert gas flow, and the second air outlet is arranged toward the lower end surface of the first inert gas flow.

[0009] As a preferred embodiment, the hot-dip galvanizing coating thickness adjustment device includes a second inert gas source for supplying gas to the air knife body, and the ratio of the gas pressure of the first inert gas source to the gas pressure of the second inert gas source is greater than or equal to 0.3 and less than or equal to 0.5.

[0010] As a preferred solution, the upper air supply hood and the lower air supply hood are both strip-shaped, and the length direction of the upper air supply hood and the length direction of the lower air supply hood are both arranged along the width direction of the strip;

[0011] A plurality of first air inlets are arranged at intervals along the length direction of the upper air supply hood, and a plurality of second air inlets are arranged at intervals along the length direction of the lower air supply hood; each of the first air inlets and each of the second air inlets are connected to the air outlet of the first inert gas source.

[0012] As a preferred solution, the gas outlet of the first inert gas source is connected to a pressure stabilizer, and each of the first gas inlets and each of the second gas inlets are connected to the gas outlet of the pressure stabilizer.

[0013] As a preferred embodiment, the pressure stabilizing member includes a box body, in which a plurality of first buffer chambers and a plurality of second buffer chambers are provided, the air inlet of each of the first buffer chambers and the air inlet of each of the second buffer chambers are connected to the air outlet of the first inert gas source; the air outlet of each of the first buffer chambers is respectively connected to each of the first air inlets; and the air outlet of each of the second buffer chambers is respectively connected to each of the second air inlets.

[0014] As a preferred embodiment, a primary buffer chamber is provided in the box body, and the primary buffer chamber is provided with a third air inlet, multiple third air outlets and multiple fourth air outlets, and the third air inlet is connected to the air outlet of the first inert gas source; each of the third air outlets is respectively connected to each of the first buffer chambers, and each of the fourth air outlets is respectively connected to each of the second buffer chambers.

[0015] As a preferred solution, the voltage stabilizer is fixedly connected to the air knife body.

[0016] As a preferred solution, the upper air supply cover is detachably connected to the upper end of the air knife body, and the lower air supply cover is detachably connected to the lower end of the air knife body.

[0017] As a preferred embodiment, the lower end of the upper air supply hood is fixedly connected to a first fixing frame, and the first fixing frame is tightly connected to the upper end of the air knife body; the upper end of the lower air supply hood is connected to a second fixing frame, and the second fixing frame is tightly connected to the lower end of the air knife body.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The method for adjusting the thickness of the hot-dip galvanized coating of the present invention comprises the following steps: an air knife body for spraying a first inert gas flow toward the surface of the strip is arranged on one side of the strip, the first inert gas flow is used to wipe the galvanized layer on the surface of the strip; a second inert gas flow and a third inert gas flow are respectively applied to the upper side and the lower side of the first inert gas flow, so that the second inert gas flow and the third inert gas flow flow to the upper end face and the lower end face of the first inert gas flow respectively, so that the second inert gas flow and the third inert gas flow fill the negative pressure areas on the upper and lower sides of the first inert gas flow, and realize the stable self-compensation of the inert gas to the low-pressure area formed around the first inert gas flow; thereby, the upper space and the lower space of the first inert gas flow are both filled with the inert gas, and the mixing of the first inert gas flow with the air caused by the presence of air in the lower space and the lower space of the first inert gas flow is avoided, the purity of the inert gas sprayed by the air knife body to the surface of the strip is improved, the amount of zinc slag formed due to oxidation is reduced, the quality of the coating on the surface of the strip is improved, and the production cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the hot-dip galvanizing coating thickness adjustment device of the present invention;

[0021] Figure 2 for Figure 1 A partial enlarged view of point C in the middle;

[0022] Figure 3 is a cross-sectional view of the upper air supply hood;

[0023] Figure 4 It is the left view of the upper air supply hood;

[0024] Figure 5 is a cross-sectional view of the lower air supply hood;

[0025] Figure 6 It is the left view of the lower air supply hood;

[0026] Figure 7 It is a top view of the voltage stabilizer;

[0027] Figure 8 This is the exploded view of the voltage stabilizer;

[0028] In the figure, 1. air knife body; 11. air knife nozzle; 2. upper air supply hood; 21. first air inlet; 22. first air outlet; 23. first fixed frame; 3. lower air supply hood; 31. second air inlet; 32. second air outlet; 33. second fixed frame; 4. box body; 41. primary buffer chamber; 411. third air inlet; 412. third air outlet; 413. fourth air outlet. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the "first" information may also be referred to as the "second" information, and similarly, the "second" information may also be referred to as the "first" information.

[0031] According to a preferred embodiment of the method for adjusting the thickness of the hot-dip galvanized coating of the present invention, an air knife body 1 for spraying a first inert gas flow toward the surface of the strip is arranged on one side of the strip, and the first inert gas flow is used to wipe the galvanized layer on the surface of the strip; a second inert gas flow and a third inert gas flow are respectively applied to the upper and lower sides of the first inert gas flow, so that the second inert gas flow and the third inert gas flow flow to the upper end face and the lower end face of the first inert gas flow respectively, so that the second inert gas flow and the third inert gas flow fill the negative pressure areas on the upper and lower sides of the first inert gas flow, and realize the stable self-compensation of the inert gas to the low-pressure area formed around the first inert gas flow; thereby, the space above and below the first inert gas flow are filled with inert gas, and the inert gas flow mixed with air caused by the presence of air in the space above and below the first inert gas flow is avoided, the purity of the inert gas sprayed by the air knife body to the surface of the strip is improved, the amount of zinc slag formed due to oxidation is reduced, the quality of the coating on the surface of the strip is improved, and the production cost is reduced.

[0032] like Figures 1 to 8As shown, a preferred embodiment of the hot-dip galvanizing coating thickness regulating device of the present invention comprises an air knife body 1 for spraying a first inert gas flow toward the strip, an upper air supply hood 2 is provided at the upper portion of the air knife body 1, and a lower air supply hood 3 is provided at the lower portion of the air knife body 1, the upper air supply hood 2 is provided with a first air inlet 21 and a first air outlet 22, the lower air supply hood 3 is provided with a second air inlet 31 and a second air outlet 32, the first air inlet 21 and the second air inlet 31 are both connected to a first inert gas source, the first air outlet 22 is arranged toward the upper end surface of the first inert gas flow, and the second air outlet 32 ​​is arranged toward the lower end surface of the first inert gas flow; thereby, the upper space and the lower space of the first inert gas flow are both filled with inert gas, avoiding the mixing of the inert gas flow and the air caused by the presence of air in the lower space and the lower space of the first inert gas flow, and improving the purity of the inert gas sprayed from the air knife body to the surface of the strip.

[0033] The hot-dip galvanizing coating thickness adjusting device comprises a second inert gas source for supplying gas to the gas knife body 1, and the ratio of the gas pressure of the first inert gas source to the gas pressure of the second inert gas source is greater than or equal to 0.3 and less than or equal to 0.5.

[0034] Specifically, the first inert gas source and the second inert gas source are both nitrogen, and the ratio of the gas pressure of the first inert gas source to the gas pressure of the second inert gas source is greater than or equal to 0.3 and less than or equal to 0.5, which can not only ensure that the upper air supply hood 2 and the lower air supply hood 3 supply sufficient inert gas to the first inert gas flow, but also avoid the first inert gas flow being disturbed due to excessive pressure of the inert gas supplied by the upper air supply hood 2 and the lower air supply hood 3, thereby ensuring that the thickness of the galvanized layer is uniform.

[0035] In this embodiment, Figure 2 As shown, the upper air supply hood 2 and the lower air supply hood 3 are both strip-shaped, and the air knife nozzle 11, the first air outlet 21 and the second air outlet 32 ​​are all strip-shaped openings arranged along the width direction of the strip. The first air outlet 22 and the second air outlet 32 ​​are arranged convexly relative to the air knife nozzle 11, and the convex distance is greater than or equal to 2mm and less than or equal to 3mm, so as to ensure that the upper air supply hood and the lower air supply hood compensate for the peripheral air flow of the first inert gas flow. A plurality of first air inlets 21 are arranged at intervals along the length direction of the upper air supply hood 2, and a plurality of second air inlets 31 are arranged at intervals along the length direction of the lower air supply hood 3; each first air inlet 21 and each second air inlet 31 are connected to the air outlet of the first inert gas source. A plurality of first air inlets 21 are arranged at intervals along the length direction of the upper air supply hood 2, so that the pressure of the air flow entering the upper air supply hood 2 can be uniform; a plurality of second air inlets 31 are arranged at intervals along the length direction of the lower air supply hood 3, so that the pressure of the air flow entering the lower air supply hood 3 can be uniform; further improving the uniformity of air supply of the hot-dip galvanizing coating thickness adjustment device of this embodiment and ensuring the uniformity of the galvanizing layer thickness.

[0036] Furthermore, the gas outlet of the first inert gas source is connected to a voltage stabilizer, and each first gas inlet 21 and each second gas inlet 31 are connected to the gas outlet of the voltage stabilizer. The voltage stabilizer can avoid uneven pressure of the inert gas flowing to each first gas inlet 21 and each second gas inlet 31, further improving the uniformity of gas replenishment of the hot-dip galvanizing coating thickness adjustment device of this embodiment and ensuring uniform thickness of the galvanized layer.

[0037] Specifically, the voltage stabilizer includes a box body 4, in which a plurality of first buffer chambers and a plurality of second buffer chambers are provided. The air inlet of each first buffer chamber and the air inlet of each second buffer chamber are connected to the air outlet of the first inert gas source; the air outlet of each first buffer chamber is respectively connected to each first air inlet 21; and the air outlet of each second buffer chamber is respectively connected to each second air inlet 31.

[0038] Furthermore, a primary buffer chamber 41 is provided in the box body 4, and the primary buffer chamber 41 is provided with a third air inlet 411, a plurality of third air outlets 412 and a plurality of fourth air outlets 413. The third air inlet 411 is connected to the air outlet of the first inert gas source; each third air outlet 412 is respectively connected to each first buffer chamber, and each fourth air outlet 413 is respectively connected to each second buffer chamber. The primary buffer chamber 41 can perform initial buffering on the inert gas entering the primary buffer chamber 41, and each first buffer chamber and each second buffer chamber can perform secondary buffering on the gas flowing out of the primary buffer chamber 41; the uniformity of air replenishment of the hot-dip galvanizing coating thickness adjustment device of this embodiment is further improved and the uniformity of the galvanizing coating thickness is ensured.

[0039] The pressure stabilizer is fixedly connected to the air knife body 1. The upper air supply cover 2 is detachably connected to the upper end of the air knife body 1, and the lower air supply cover 3 is detachably connected to the lower end of the air knife body 1. The pressure stabilizer, the upper air supply cover and the lower air supply cover are all connected to the air knife body 1, and when the position of the air knife body is adjusted, the pressure stabilizer, the upper air supply cover 2 and the lower air supply cover 3 can move synchronously, so that the hot-dip galvanizing coating thickness adjustment device of this embodiment is easy to adjust.

[0040] Specifically, the lower end of the upper air supply hood 2 is fixedly connected to a first fixing frame 23, and the first fixing frame 23 is fastened to the upper end of the air knife body 1; the upper end of the lower air supply hood 3 is connected to a second fixing frame 33, and the second fixing frame 33 is fastened to the lower end of the air knife body 1.

[0041] In summary, in the method for adjusting the thickness of the hot-dip galvanized coating of the present invention, an air knife body 1 for spraying a first inert gas flow toward the surface of the strip is arranged on one side of the strip, and the first inert gas flow is used to wipe the galvanized layer on the surface of the strip; a second inert gas flow and a third inert gas flow are respectively applied to the upper and lower sides of the first inert gas flow, so that the second inert gas flow and the third inert gas flow flow to the upper end face and the lower end face of the first inert gas flow respectively, so that the first inert gas flow and the second inert gas flow fill the negative pressure areas on the upper and lower sides of the first inert gas flow, and realize stable self-compensation of the inert gas to the low-pressure area formed around the first inert gas flow; thereby, the space above and below the first inert gas flow are filled with inert gas, and the first inert gas flow is avoided from being mixed with air due to the presence of air in the space above and below the first inert gas flow, thereby improving the purity of the first inert gas sprayed by the air knife body to the surface of the strip, reducing the amount of zinc slag formed due to oxidation, improving the quality of the coating on the surface of the strip, and reducing the production cost.

[0042] The hot-dip galvanizing coating thickness regulating device of the present invention comprises an air knife body 1 for spraying a first inert gas flow toward a steel strip, an upper air supply hood 2 is provided at the upper part of the air knife body 1, and a lower air supply hood 3 is provided at the lower part of the air knife body 1, the upper air supply hood 2 is provided with a first air inlet 21 and a first air outlet 22, and the lower air supply hood 3 is provided with a second air inlet 31 and a second air outlet 32, the first air inlet 21 and the second air inlet 31 are both connected to a first inert gas source, the first air outlet 22 is arranged toward the upper end surface of the first inert gas flow, and the second air outlet 32 ​​is arranged toward the lower end surface of the first inert gas flow; thereby, the upper space and the lower space of the first inert gas flow are both filled with inert gas, avoiding the mixing of the first inert gas flow with air caused by the presence of air in the lower space and the lower space of the first inert gas flow, and improving the purity of the inert gas sprayed from the air knife body to the surface of the steel strip.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A hot dip galvanizing coating thickness adjustment device, characterized in that: The invention comprises an air knife body (1) for spraying a first inert gas flow toward a steel strip, wherein an upper gas supply hood (2) is provided at the upper part of the air knife body (1), and a lower gas supply hood (3) is provided at the lower part of the air knife body (1), wherein the upper gas supply hood (2) is provided with a first gas inlet (21) and a first gas outlet (22), and the lower gas supply hood (3) is provided with a second gas inlet (31) and a second gas outlet (32), wherein the first gas inlet (21) and the second gas inlet (31) are both connected to a first inert gas source, the first gas outlet (22) is arranged toward the upper end surface of the first inert gas flow, and the second gas outlet (32) is arranged toward the upper end surface of the first inert gas flow. The hot-dip galvanizing coating thickness adjusting device comprises a second inert gas source for supplying gas to the air knife body (1), and the ratio of the gas pressure of the first inert gas source to the gas pressure of the second inert gas source is greater than or equal to 0.3 and less than or equal to 0.5; the first gas outlet (22) and the second gas outlet (32) are 2 mm to 3 mm protruding forward relative to the air knife nozzle (11) of the air knife body (1); the upper air supply cover (2) is detachably connected to the upper end of the air knife body (1), and the lower air supply cover (3) is detachably connected to the lower end of the air knife body (1).

2. The hot-dip galvanizing coating thickness adjustment device according to claim 1, characterized in that: The upper air supply hood (2) and the lower air supply hood (3) are both strip-shaped, and the length direction of the upper air supply hood (2) and the length direction of the lower air supply hood (3) are both arranged along the width direction of the strip; A plurality of first air inlets (21) are arranged at intervals along the length direction of the upper air supply hood (2), and a plurality of second air inlets (31) are arranged at intervals along the length direction of the lower air supply hood (3); each of the first air inlets (21) and each of the second air inlets (31) are connected to the air outlet of the first inert gas source.

3. The hot-dip galvanizing coating thickness adjusting device according to claim 2, characterized in that: The gas outlet of the first inert gas source is connected to a voltage stabilizer, and each of the first gas inlets (21) and each of the second gas inlets (31) are in communication with the gas outlet of the voltage stabilizer.

4. The hot-dip galvanizing coating thickness adjusting device according to claim 3, characterized in that: The voltage stabilizing component comprises a box body (4), wherein a plurality of first buffer chambers and a plurality of second buffer chambers are arranged in the box body (4), wherein the air inlet of each of the first buffer chambers and the air inlet of each of the second buffer chambers are both connected to the air outlet of the first inert gas source; the air outlet of each of the first buffer chambers is respectively connected to each of the first air inlets (21); and the air outlet of each of the second buffer chambers is respectively connected to each of the second air inlets (31).

5. The hot-dip galvanizing coating thickness adjusting device according to claim 3, characterized in that: The voltage stabilizing component comprises a box body (4), wherein a plurality of first buffer chambers and a plurality of second buffer chambers are arranged in the box body (4), wherein a primary buffer chamber (41) is arranged in the box body (4), wherein the primary buffer chamber (41) is provided with a third air inlet (411), a plurality of third air outlets (412) and a plurality of fourth air outlets (413), wherein the third air inlet (411) is connected to the air outlet of the first inert gas source; each of the third air outlets (412) is respectively connected to each of the first buffer chambers, and the air outlet of each of the first buffer chambers is respectively connected to each of the first air inlets (21); each of the fourth air outlets (413) is respectively connected to each of the second buffer chambers, and the air outlet of each of the second buffer chambers is respectively connected to each of the second air inlets (31).

6. The hot-dip galvanizing coating thickness adjusting device according to claim 3, characterized in that: The pressure stabilizing component is fixedly connected to the air knife body (1).

7. The hot-dip galvanizing coating thickness adjusting device according to claim 1, characterized in that: The lower end of the upper air supply hood (2) is fixedly connected to a first fixing frame (23), and the first fixing frame (23) is tightly connected to the upper end of the air knife body (1); the upper end of the lower air supply hood (3) is connected to a second fixing frame (33), and the second fixing frame (33) is tightly connected to the lower end of the air knife body (1).

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