A method for controlling and treating slagging on the skirt of a continuous hot-dip galvanizing furnace nose

Abstract

The present invention discloses a method for controlling and treating slagging of the skirt of a continuous hot-dip galvanizing furnace nose, and belongs to the technical field of cold-rolled hot-dip galvanized sheet and strip processing. The present invention comprises the following steps: S1: the aluminum content of the zinc pot is controlled within the range of 0.18-0.30%, and the iron content of the zinc pot is controlled within the range of <0.015%; S2: the temperature of the zinc pot is controlled within the range of 450-460°C, and the zinc ingot is added in an automatic closed-loop mode; S3: the overflow plate around the skirt of the furnace nose is treated with an anti-sticking zinc coating; S4: the deformation of the lip of the furnace nose skirt must be ≤5mm; S5: the purge gas flow rate of the camera of the furnace nose skirt is <1m 3 / h; S6: according to the product type and surface grade, combined with the observation of the furnace nose camera, the lip micro-slag is subjected to sedimentation and soaking treatment; S7: according to the product type and surface grade, different control modes are selected, that is, the overflow volume and the sedimentation treatment frequency are distinguished. The present invention can achieve effective control and prevention of skirt slag, thereby reducing product surface defects such as zinc ash and zinc slag.

Description

Technical Field

[0001] The invention relates to the technical field of cold-rolled hot-dip galvanized sheet and strip processing, and in particular to a method for controlling and treating slagging at the skirt of a continuous hot-dip galvanizing furnace nose. Background Art

[0002] The continuous hot-dip galvanizing unit includes core equipment such as welding machine, cleaning section, annealing furnace, zinc pot, air knife, skin pass machine, straightening machine, trimming shear, oiling machine, etc. As users' requirements for product quality continue to increase, the requirements for product defect control have become more stringent. Therefore, it is necessary to comprehensively guarantee the improvement of the overall defect control level from the aspects of improving equipment accuracy and process control level. The control of zinc ash defects in galvanized steel has always been a hot topic discussed in the continuous hot-dip galvanizing industry. The industry generally adopts methods such as furnace nose humidification, adding zinc ash pumps, and increasing furnace nose insulation to control defects. The ultimate goal is to ensure that the strip steel remains free of foreign matter before or during immersion in the plating solution, so as to achieve the purpose of consistent and uniform coating quality. In order to ensure the effective realization of key products such as galvanized automobile outer panels and further reduce internal quality losses, it is necessary to further analyze the causes of slag formation on the furnace nose skirt and formulate effective control methods. Summary of the invention

[0003] The object of the present invention is to provide a method for controlling and treating slagging on the skirt of a continuous hot-dip galvanizing furnace nose, which can quickly and effectively prevent slagging on the skirt of the furnace nose, and achieve effective control and prevention of slagging on the skirt by ensuring the processing accuracy of the furnace nose skirt and dynamically adjusting the process during the production process, thereby reducing surface defects of products such as zinc ash and zinc slag.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for controlling and treating slagging at the skirt edge of a continuous hot-dip galvanizing furnace nose, comprising the following steps:

[0005] S1: The aluminum content of the zinc pot is controlled within the range of 0.18-0.30%, and the iron content of the zinc pot is controlled within the range of <0.015%;

[0006] S2: The temperature of the zinc pot is controlled at 450-460℃, and the zinc ingot is added in an automatic closed-loop mode. Each zinc ingot is fed into the zinc pot ≥15 times, and the feeding length each time is ≤10cm. The fluctuation range of the main liquid level of the zinc pot is controlled within the target value ±1mm;

[0007] S3: The overflow plate around the furnace nose skirt is treated with anti-stick zinc coating;

[0008] S4: The deformation of the lip of the furnace nose skirt must be ≤5mm;

[0009] S5: Furnace nose skirt camera purge gas flow rate <1m 3 / h, the camera light source adopts cold light LED, and the inner glass of the lampshade is disassembled and cleaned every 15 days;

[0010] S6: According to the product type and surface grade, combined with the observation of the furnace nose camera, the lip micro-slag is treated by sedimentation and soaking: the furnace nose is telescoped down by 20mm, the zinc slag pump speed is increased by 100 rpm, and the original parameters are restored after 3 minutes of soaking;

[0011] S7: Select different control modes according to product type and surface grade, that is, distinguish the overflow volume and sedimentation treatment frequency. The specific rules are as follows:

[0012]

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The invention discloses a method for controlling and treating slagging on the skirt of a continuous hot-dip galvanizing furnace nose, which can quickly and effectively prevent slagging on the skirt of the furnace nose. By optimizing the zinc pot process, the deformation amount of the lip of the furnace nose skirt and the processing technology, the slagging on the lip of the furnace nose is effectively controlled and prevented, thus laying a foundation for the effective control of zinc ash and zinc slag defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top view schematic diagram of the furnace nose skirt of the present invention;

[0016] Figure 2 It is a side cross-sectional view of the furnace nose skirt of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-2 In the embodiment of the present invention, a method for controlling and treating slagging on the skirt of a continuous hot-dip galvanizing furnace nose is provided. The main process flow of continuous hot-dip galvanizing is hot alkali immersion → alkali brushing → electrolytic cleaning → hot water brushing → annealing → hot dip plating → cooling after plating → skin finishing → trimming → oiling → coiling. The skirt of the furnace nose adopts a four-sided overflow form. In order to ensure the perfect realization of the overflow effect, the zinc pot liquid level control, overflow plate precision control and slagging rapid disposal method are integrated. The specific scheme is as follows:

[0019] S1: The aluminum content of the zinc pot is controlled within the range of 0.18-0.30%, and the iron content of the zinc pot is controlled within the range of <0.015%;

[0020] S2: The temperature of the zinc pot is controlled at 450-460℃, and the zinc ingot is added in an automatic closed-loop mode. Each zinc ingot is fed into the zinc pot ≥15 times, and the feeding length each time is ≤10cm. The fluctuation range of the main liquid level of the zinc pot is controlled within the target value ±1mm;

[0021] S3: The overflow plate around the furnace nose skirt is treated with anti-stick zinc coating;

[0022] S4: The deformation of the lip of the furnace nose skirt must be ≤5mm, that is, the absolute values ​​of B1-B0, B1-B2, and B0-B2 in the figure are all ≤5mm;

[0023] S5: The purge air flow rate of the furnace nose skirt camera is less than 1m3 / h, the camera light source adopts cold light LED, and the inner wall glass of the lampshade is disassembled and cleaned every 15 days;

[0024] S6: According to the product type and surface grade, combined with the observation of the furnace nose camera, the lip micro-slag is treated by sedimentation and soaking; the first step: the furnace nose is telescopically lowered by 20mm, the second step: the zinc slag pump speed is increased by 100 rpm, the third step: the slag dam is kept soaked for 3 minutes, and the fourth step: the zinc nose telescopic position and the zinc slag pump speed are restored to the parameters before adjustment;

[0025] S7: Differentiate the overflow volume and sedimentation cleaning frequency according to product type and surface grade, and make adjustments according to the rules described in the table below.

[0026]

[0027] ① Liquid level difference H=H1-H0, the main liquid level, i.e. the zinc pot level, is H1, and the internal liquid level, i.e. the zinc liquid position in the dam tank, is H0. ② The micro overflow mode is the liquid level difference H≤1mm, the medium overflow mode is the liquid level difference 1mm<H<5mm, and the large overflow mode is H>5mm. For details, refer to Figure 2 .

[0028] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for controlling and treating slagging on the skirt of a continuous hot-dip galvanizing furnace nose, characterized in that: The following steps are involved: S1: The aluminum content of the zinc pot is controlled within the range of 0.18-0.30%, and the iron content of the zinc pot is controlled within the range of <0.015%; S2: The temperature of the zinc pot is controlled at 450-460℃, and the zinc ingot is added in an automatic closed-loop mode. Each zinc ingot is fed into the zinc pot ≥15 times, and the feeding length each time is ≤10cm. The fluctuation range of the main liquid level of the zinc pot is controlled within the target value ±1mm; S3: The overflow plate around the furnace nose skirt is treated with anti-stick zinc coating; S4: The deformation of the lip of the furnace nose skirt must be ≤5mm; S5: Furnace nose skirt camera purge gas flow rate <1m 3 / h, the camera light source adopts cold light LED, and the inner glass of the lampshade is disassembled and cleaned every 15 days; S6: According to the product type and surface grade, combined with the observation of the furnace nose camera, the lip micro-slag is treated by sedimentation and soaking: the furnace nose is telescoped down by 20mm, the zinc slag pump speed is increased by 100 rpm, and the original parameters are restored after 3 minutes of soaking; S7: Select different control modes according to product type and surface grade, that is, distinguish the overflow volume and sedimentation treatment frequency. The specific rules are as follows: The liquid level difference H=H1-H0, the main liquid level, i.e. the zinc pot level, is H1, and the internal liquid level, i.e. the position of the zinc liquid in the dam tank, is H0; the micro-overflow mode is the liquid level difference H≤1mm, the medium overflow mode is the liquid level difference 1mm<H<5mm, and the large overflow mode is H>5mm.

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