Continuous hot coating air knife heating device

Abstract

The utility model relates to a continuous hot coating air knife heating device, and belongs to the technical field of steel rolling in the metallurgical industry. According to the technical scheme, the device comprises a heater (11), a radiant tube (12), an air inlet pipe (15), an air outlet pipe (16) and a heating pipe (17), the two ends of the heating pipe (17) are of closed structures, the radiant tube (12) connected with the heater (11) is arranged in the heating pipe (17), one end of the heating pipe (17) is connected with the air inlet pipe (15), the other end of the heating pipe (17) is connected with the air outlet pipe (16), and the air outlet pipe (16) leads to a continuous hot coating air knife; a heat preservation layer (13) is arranged outside the heating pipe (17); and a temperature detector (14) is arranged on an air outlet pipe (16) of the heating pipe (17). The device has the beneficial effects that the defects of snow patterns and zinc flow lines caused by too fast temperature drop after the strip steel is discharged from the air knife are prevented, and high-quality and stable production of zinc-aluminum-magnesium products is realized.

Description

Technical Field

[0001] The utility model relates to a continuous hot-dip coating air knife heating device, belonging to the technical field of steel rolling in the metallurgical industry. Background Art

[0002] Zinc-aluminum-magnesium products have prominent corrosion resistance advantages and have been widely used in fields such as building materials, household appliances, and automobiles. However, compared with galvanized products, it is more difficult to control the surface quality of zinc-aluminum-magnesium products. To meet customer requirements, when producing zinc-aluminum-magnesium products, it is necessary not only to reduce the accumulation of zinc slag defects on the strip surface, but also to control the snowflake pattern defects generated during the production of thin gauges, and to solve the zinc flow pattern problem caused by the thick gauge thickness layer during production.

[0003] To avoid the generation of snowflake pattern defects in thin gauges of zinc-aluminum-magnesium products, the temperature of the strip after passing through the air knife should be controlled above 425°C; to avoid the generation of zinc flow pattern defects in the thick gauge thickness layer of zinc-aluminum-magnesium products, the temperature of the strip after passing through the air knife should be controlled above 430°C. Due to the intervention of magnesium elements, zinc slag defects are extremely likely to occur during the production of zinc-aluminum-magnesium products. Simply increasing the zinc pot temperature and the strip inlet zinc pot temperature can make the temperature of the strip after passing through the air knife meet the control requirements for snowflake pattern and zinc flow pattern defects, but it cannot avoid the large amount of zinc slag defects caused by the increase in pot temperature. Therefore, when the strip enters the air knife after leaving the zinc pot, it is very necessary to use an external heating method to slow down the temperature drop rate of the strip so that the strip can meet the temperature control requirements for snowflake pattern and zinc flow pattern defects after passing through the air knife. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a continuous hot-dip coating air knife heating device to prevent the temperature of the strip from dropping too fast after passing through the air knife, resulting in snowflake pattern and zinc flow pattern defects, and to achieve high-quality and stable production of zinc-aluminum-magnesium products, and solve the problems existing in the background art.

[0005] The technical solution of the utility model is as follows:

[0006] A continuous hot-dip coating air knife heating device includes a heater, a radiation tube, an inlet pipe, an outlet pipe, and a heating pipe. Both ends of the heating pipe are closed structures. A radiation tube connected to the heater is provided inside the heating pipe. One end of the heating pipe is connected to the inlet pipe, and the other end of the heating pipe is connected to the outlet pipe. The outlet pipe leads to a continuous hot-dip coating air knife.

[0007] A heat insulation layer is provided outside the heating pipe.

[0008] A thermometer is provided on the outlet pipe of the heating pipe.

[0009] The outlet pipe of the heating pipe is close to the heater end of the radiation tube.

[0010] The beneficial effects of the present utility model are as follows: Under the condition that the temperature of the strip entering the pot and the temperature of the zinc pot are stable at 435 - 445 °C, the air knife is heated by the heated nitrogen gas to prevent the temperature of the strip from dropping too fast after exiting the air knife, resulting in defects such as snowflake patterns and zinc flow patterns, and achieving high-quality and stable production of zinc-aluminum-magnesium products. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the present utility model;

[0012] Figure 2 It is a sectional view of the present utility model;

[0013] In the figure: heating device 1, air knife 2, temperature measuring gun 3, strip 4;

[0014] Heater 11, radiation tube 12, heat insulation layer 13, thermometer 14, inlet pipe 15, outlet pipe 16, heating pipe 17. SPECIFIC EMBODIMENTS

[0015] The following further illustrates the present utility model through examples in conjunction with the accompanying drawings.

[0016] Refer to the attached Figure 1-2 , a continuous hot-dip coating air knife heating device, which includes a heater 11, a radiation tube 12, an inlet pipe 15, an outlet pipe 16 and a heating pipe 17. Both ends of the heating pipe 17 are closed structures. A radiation tube 12 connected to the heater 11 is arranged inside the heating pipe 17. One end of the heating pipe 17 is connected to the inlet pipe 15, and the other end of the heating pipe 17 is connected to the outlet pipe 16. The outlet pipe 16 leads to the continuous hot-dip coating air knife.

[0017] In this embodiment, refer to the attached Figure 1 , 2 , the air knife 2 is located above the zinc liquid surface, the temperature measuring gun 3 is located directly in front of the strip 4, and the measuring point of the temperature measuring gun 3 is located at a position 150 mm after the strip 4 exits the air knife.

[0018] There are 2 groups of this heating device 1, both of which are located on the left side of the strip and are arranged side by side closely, as shown in the attached Figure 1As shown. Each heating device 1 includes a heater 11, a radiation tube 12, a heat insulation layer 13, a thermometer 14, an inlet pipe 15, an outlet pipe 16 and a heating pipe 17. Among them, the heating pipe 17 has a diameter of 250 mm and a height of 1100 mm, and both ends are closed. The heating pipe 17 is wrapped with a heat insulation layer 13, and the heat insulation layer 13 is made of polyurethane heat insulation material, which has a low thermal conductivity and good heat resistance. The radiation tube 12 uses a strip-shaped spiral to surround the electric heating radiation tube, with a large heat radiation surface and strong heating capacity. The radiation tube 12 is connected to the heater 11, and both the heater 11 and the radiation tube 12 are existing heating components. The inlet pipe 15 is connected to the nitrogen gas network, the inlet pipe 15 is connected to the lower part of the heating pipe 7, and the medium introduced is pure nitrogen. The outlet pipe 16 is connected to the upper part of the heating pipe 17, on the same side as and parallel to the inlet pipe 15. The thermometer 14 is installed on the outlet pipe 16, and the outlet pipe 16 is connected to the air knife 2.

[0019] The strip steel 4 comes out of the zinc pot and enters the air knife 2. After the strip steel 4 exits the air knife, it is measured by the temperature measuring gun 3. This heating device 1 adopts a negative feedback control mechanism. During the specification switching in the production process, the temperature measuring gun 3 feeds back the temperature of the strip steel exiting the air knife to the heating device 1. The heating device 1 adjusts the heating power by comparing the temperature value displayed by the thermometer 14 on the outlet pipe 16. The radiation tube 12 heats the nitrogen gas entering the heating pipe 1 from the inlet pipe 15. After heating, the nitrogen gas enters the air knife 2 from the outlet pipe 16, and the air knife 2 realizes the heating function of the air knife 2 by blowing the strip steel with the heated nitrogen gas.

Claims

1. A continuous hot coating air knife heating device, characterized in that: The invention comprises a heater (11), a radiation tube (12), an air inlet pipe (15), an air outlet pipe (16) and a heating tube (17); both ends of the heating tube (17) are closed structures; a radiation tube (12) connected to the heater (11) is arranged inside the heating tube (17); one end of the heating tube (17) is connected to the air inlet pipe (15); the other end of the heating tube (17) is connected to the air outlet pipe (16); and the air outlet pipe (16) leads to a continuous hot-dip coating air knife.

2. The continuous hot coating air knife heating device according to claim 1, characterized in that: The outside of the heating tube (17) is provided with a heat-insulating layer (13).

3. The continuous hot coating air knife heating device according to claim 1, characterized in that: A temperature meter (14) is provided on the air outlet pipe (16) of the heating pipe (17).

4. The continuous hot coating air knife heating device according to claim 1, characterized in that: The air outlet pipe (16) of the heating tube (17) is close to one end of the heater (11) of the radiation tube (12).

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