Coating thickness control device for hot-rolled ribbed steel bar

Abstract

The utility model provides a plating thickness control device for hot-rolled ribbed steel bars. The plating thickness control device comprises a first air knife, a second air knife and a third air knife which are sequentially arranged at the downstream of a galvanizing bath along the conveying direction of the ribbed steel bars, each of the first air knife, the second air knife and the third air knife is of a hollow structure shaped like a Chinese character'hui ', a conveying channel is correspondingly formed in each air knife, and a plurality of nozzles facing the center of the conveying channel are arranged on the periphery of each conveying channel; the blowing direction of the first air knife nozzles is inclined towards the running direction of the ribbed steel bars, the blowing direction of the second air knife nozzles is perpendicular to the running direction of the ribbed steel bars, and the blowing direction of the third air knife nozzles is inclined opposite to the running direction of the ribbed steel bars. The three air knives which are continuously arranged and have different blowing angles are used for blowing off redundant zinc liquid attached to the surface of the reinforcing steel bar, it is guaranteed that the thicknesses of coatings of all parts of the surface of the ribbed reinforcing steel bar are consistent, and the effect is quite remarkable especially for the part, where zinc liquid is prone to being accumulated, of the joint of a transverse rib and a reinforcing steel bar body.

Description

Technical Field

[0001] The utility model relates to the technical field of ribbed steel bars, in particular to a coating thickness control device for hot-rolled ribbed steel bars. Background Art

[0002] Hot-rolled ribbed steel bars, commonly known as threaded steel bars, have high strength, high toughness, and good seismic resistance. They are ideal products for high-rise buildings and are widely used in the field of building concrete. In order to increase the corrosion resistance of steel bars and improve the strength and life of reinforced concrete, hot-dip galvanizing is usually performed on the outside of hot-rolled ribbed steel bars. After hot-dip galvanizing, the surface of the steel bar is covered with a pure zinc layer in the form of complete physical protection. A Zn-Fe alloy layer is also formed between the pure zinc layer and the steel bar matrix, which isolates the steel bar matrix from the atmosphere, thereby protecting the steel bar matrix from corrosion.

[0003] Since there are protruding transverse ribs on the surface of ribbed steel bars, the angle between the transverse ribs and the steel bar body becomes a difficult point to control the galvanizing thickness. The zinc layer thickness at the angle between the transverse ribs and the steel bar body and between the transverse ribs tends to be thicker. The increase in zinc layer thickness will reduce the surface area of ​​the ribbed steel bar and affect its bonding with concrete. Therefore, how to control the coating thickness and uniformity of hot-rolled ribbed steel bars has become a key issue restricting the quality of galvanizing of ribbed steel bars. Utility Model Content

[0004] The utility model provides a coating thickness control device for hot-rolled ribbed steel bars in order to overcome the drawbacks of the prior art.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A coating thickness control device for hot-rolled ribbed steel bars, comprising a first air knife, a second air knife and a third air knife which are sequentially arranged at the downstream of a galvanizing tank along the conveying direction of the ribbed steel bars; the first air knife, the second air knife and the third air knife are all "U"-shaped hollow structures, and conveying channels for the hot-rolled ribbed steel bars to pass through are correspondingly opened inside the structures, and an air cavity is formed between the conveying channel and the outer wall of the air knife; the top and the bottom of the air cavity are respectively connected to compressed air pipes, and a plurality of nozzles connected to the air cavity and facing the center of the conveying channel are respectively arranged around the conveying channel;

[0007] The spraying direction of the first air knife nozzle is inclined toward the running direction of the ribbed steel bars, the spraying direction of the second air knife nozzle is perpendicular to the running direction of the ribbed steel bars, and the spraying direction of the third air knife nozzle is inclined opposite to the running direction of the ribbed steel bars.

[0008] A further improvement of the utility model is that the angle α between the blowing direction of the first air knife nozzle and the running direction of the ribbed steel bar is 130°~150°, and the angle β between the blowing direction of the third air knife nozzle and the running direction of the ribbed steel bar is 40°~50°.

[0009] A further improvement of the utility model is that the coating thickness control device for hot-rolled ribbed steel bars also includes a first guide groove arranged between the first air knife and the second air knife, a second guide groove arranged between the second air knife and the third air knife, and a third guide groove arranged downstream of the third air knife.

[0010] A further improvement of the utility model is that a zinc liquid recovery tank for receiving the blown-off zinc liquid is also arranged below the first air knife, the second air knife and the third air knife, and the zinc liquid recovery tank is connected to the zinc pot.

[0011] A further improvement of the utility model is that the bottom of the zinc liquid recovery tank is arranged to be inclined toward the zinc pot.

[0012] A further improvement of the utility model is that a heating plate is arranged at the bottom of the zinc liquid recovery tank.

[0013] A further improvement of the utility model is that the coating thickness control device for hot-rolled ribbed steel bars also includes a sealing outer cover covering the first air knife, the first guide groove, the second air knife, the second guide groove, the third air knife, and the third guide groove.

[0014] The beneficial effects of the utility model are:

[0015] The utility model provides a coating thickness control device for hot-rolled ribbed steel bars, which blows off the excess zinc liquid attached to the steel bar surface through three air knives that are continuously set and have different spray angles, ensuring that the coating thickness of each part of the ribbed steel bar surface is consistent, especially for the part where the zinc liquid is easily accumulated at the intersection of the transverse rib and the steel bar body, the effect is very significant. The coating thickness of the ribbed steel bar surface is consistent, ensuring that the control parameters such as the height of the transverse rib meet the relevant requirements, and further ensuring the performance parameters such as the strength of the ribbed steel bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the overall structure connection flow chart of the utility model;

[0017] Figure 2 Schematic diagram of the side structure of the air knife;

[0018] Figure 3 is a schematic diagram of the spray angle α of the first air knife nozzle;

[0019] Figure 4 is a schematic diagram of the spray angle β of the third air knife nozzle;

[0020] In the figure: 1. first air knife, 2. second air knife, 3. third air knife, 4. first guide groove, 5. second guide groove, 6. third guide groove, 7. zinc liquid recovery groove, 8. heating plate, 9. sealing cover, 10. conveying channel, 11. air cavity, 12. nozzle, 13. galvanizing groove, 14. zinc pot, 15. venting tower, 16. ribbed steel bar, 17. compressed air pipe. DETAILED DESCRIPTION

[0021] The utility model will be further described below in conjunction with the accompanying drawings.

[0022] A coating thickness control device for hot-rolled ribbed steel bars, such as Figure 1 , Figure 2 As shown, it includes a first air knife 1, a second air knife 2 and a third air knife 3 which are sequentially arranged downstream of a galvanizing tank 13 along the conveying direction of ribbed steel bars 16. The first air knife 1, the second air knife 2 and the third air knife 3 are all "U"-shaped hollow structures, and conveying channels 10 for hot-rolled ribbed steel bars 16 to pass through are correspondingly opened inside the first air knife 1, the second air knife 2 and the third air knife 3, and an air cavity 11 is formed between the conveying channel 10 and the outer wall of the air knife. The top and bottom of the air cavity 11 are respectively connected to a compressed air pipe 17.

[0023] A plurality of nozzles 12 are arranged around the conveying channel 10, the nozzles 12 are connected to the air cavity 11, and the nozzles 12 are all facing the center of the conveying channel 10. Compressed nitrogen is simultaneously ejected from the plurality of nozzles 12 through the air cavity 11, and the surface of the galvanized hot-rolled ribbed steel bars 16 being conveyed is omni-directionally purged to remove excess zinc liquid.

[0024] like Figure 3 , Figure 4 As shown, the blowing direction of the first air knife 1 nozzle 12 is inclined toward the running direction of the ribbed steel bar 16, and the angle α between the blowing direction of the first air knife 1 nozzle 12 and the running direction of the ribbed steel bar 16 is 130°~150°; the blowing direction of the second air knife 2 nozzle 12 is perpendicular to the running direction of the ribbed steel bar 16; the blowing direction of the third air knife 3 nozzle 12 is inclined in the opposite direction of the running direction of the ribbed steel bar 16, and the angle β between the blowing direction of the third air knife 3 nozzle 12 and the running direction of the ribbed steel bar 16 is 40°~50°. The excess zinc liquid attached to the surface of the transverse ribs of the ribbed steel bar 16 is blown away by blowing at three different angles of air knives. The angle between the blowing direction of the first air knife 1 nozzle 12 / the blowing direction of the third air knife 3 nozzle 12 and the running direction of the ribbed steel bar 16 can be adjusted and changed according to the size of the transverse ribs of the ribbed steel bar 16, so that it is consistent with the inclination angle of the transverse rib surface.

[0025] Preferably, since the ribbed steel bars 16 after the hot rolling are cut into multiple pieces and arranged side by side and conveyed forward synchronously, in order to ensure the effect of blowing away the zinc liquid, the number of nozzles 12 located above and below is not less than the number of ribbed steel bars 16, and they are evenly distributed along the width direction to ensure that the surfaces of the multiple ribbed steel bars 16 are synchronously blown. The number of nozzles 12 located on both sides of the ribbed steel bars 16 is preferably two.

[0026] In order to ensure the stable forward transportation of the galvanized hot-rolled ribbed steel bars 16, a first guide groove 4 is provided between the first air knife 1 and the second air knife 2, a second guide groove 5 is provided between the second air knife 2 and the third air knife 3, and a third guide groove 6 is provided at the rear end of the third air knife 3. The inlet ends of the first guide groove 4, the second guide groove 5, and the third guide groove 6 are all connected to the trumpet mouth with a larger front and a smaller rear, which can laterally constrain and smooth the multiple ribbed steel bars 16, so that they can be smoothly and continuously transported to avoid steel piling.

[0027] A zinc liquid recovery tank 7 is also provided below the first air knife 1, the second air knife 2 and the third air knife 3, and the zinc liquid recovery tank 7 is directly connected to the zinc pot 14. The zinc liquid blown off by the air knife falls into the zinc liquid recovery tank 7, and returns to the zinc pot 14 for reuse after being enriched.

[0028] In order to prevent the dripping zinc liquid from solidifying in the zinc liquid recovery tank 7 and being unable to be recovered, a heating plate 8 is arranged at the bottom of the zinc liquid recovery tank 7. While keeping the zinc liquid in liquid state, the zinc liquid recovery tank 7 will also affect the temperature of the galvanized ribbed steel bars 16 passing thereover, so that the galvanized ribbed steel bars 16 are kept at a constant temperature, and the coating is prevented from cooling and solidifying in advance, which affects the subsequent purge control of the coating by the air knife.

[0029] Preferably, in order to further ensure the temperature stability of the galvanized ribbed steel bars 16, the coating thickness control device also includes a sealed outer cover 9, which is connected to the zinc pot 14, and the first air knife 1, the first guide groove 4, the second air knife 2, the second guide groove 5, the third air knife 3, and the third guide groove 6 are all arranged in the sealed outer cover 9 to prevent heat dissipation.

[0030] In order to facilitate the reflux of the zinc liquid in the zinc liquid recovery tank 7 , the bottom of the zinc liquid recovery tank 7 is arranged to be inclined toward the zinc pot 14 .

[0031] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A coating thickness control device for hot-rolled ribbed steel bars, characterized in that: The invention comprises a first air knife (1), a second air knife (2) and a third air knife (3) which are arranged in sequence downstream of a galvanizing tank (13) along the conveying direction of ribbed steel bars (16); the first air knife (1), the second air knife (2) and the third air knife (3) are all hollow structures in the shape of a Chinese character “U”, and a conveying channel (10) for the hot-rolled ribbed steel bars (16) to pass through is correspondingly provided inside the first air knife (1), and an air cavity (11) is formed between the conveying channel (10) and the outer wall of the air knife; the top and the bottom of the air cavity (11) are respectively connected to a compressed air pipe (17), and a plurality of nozzles (12) which are connected to the air cavity (11) and face the center of the conveying channel (10) are respectively arranged around the conveying channel (10); The blowing direction of the first air knife (1) is inclined toward the running direction of the ribbed steel bar (16), the blowing direction of the second air knife (2) is perpendicular to the running direction of the ribbed steel bar (16), and the blowing direction of the third air knife (3) is inclined in the opposite direction to the running direction of the ribbed steel bar (16).

2. The coating thickness control device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The angle α between the blowing direction of the first air knife (1) and the running direction of the ribbed steel bar (16) is 130° to 150°, and the angle β between the blowing direction of the third air knife (3) and the running direction of the ribbed steel bar (16) is 40° to 50°.

3. The coating thickness control device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The coating thickness control device for hot-rolled ribbed steel bars further comprises a first guide groove (4) arranged between the first air knife (1) and the second air knife (2), a second guide groove (5) arranged between the second air knife (2) and the third air knife (3), and a third guide groove (6) arranged downstream of the third air knife (3).

4. The coating thickness control device for hot-rolled ribbed steel bars according to claim 3, characterized in that: A zinc liquid recovery tank (7) for receiving blown-off zinc liquid is also provided below the first air knife (1), the second air knife (2) and the third air knife (3); the zinc liquid recovery tank (7) is connected to the zinc pot (14).

5. The coating thickness control device for hot-rolled ribbed steel bars according to claim 4, characterized in that: The bottom of the zinc liquid recovery tank (7) is arranged to be inclined toward the zinc pot (14).

6. The coating thickness control device for hot-rolled ribbed steel bars according to claim 5, characterized in that: A heating plate (8) is arranged at the bottom of the zinc liquid recovery tank (7).

7. The coating thickness control device for hot-rolled ribbed steel bars according to claim 3, characterized in that: The coating thickness control device for hot-rolled ribbed steel bars (16) further comprises a sealing outer cover (9) covering the outside of the first air knife (1), the first guide groove (4), the second air knife (2), the second guide groove (5), the third air knife (3), and the third guide groove (6).

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