A continuous production process and system for aluminized zinc steel plate

Abstract

The present application relates to a kind of continuous production system of aluminized zinc steel plate, including two uncoilers and two coilers located at both ends, welding machine is equipped behind uncoiler, inlet loop is equipped behind welding machine, steel belt cleaning system is equipped behind inlet loop, steel belt heating system is equipped behind steel belt cleaning system, zinc pot is equipped behind steel belt heating system, air knife is equipped above zinc pot, uplink cooling system is equipped above air knife, downlink cooling system is equipped behind uplink cooling system, water quenching tank is equipped below downlink cooling system, finishing machine and straightening machine are sequentially equipped behind water quenching tank, two chromium acid coating machines in vertical arrangement are equipped behind straightening machine, resin coating machine is equipped behind chromium acid coating machine, outlet loop is equipped behind resin coating machine.The beneficial effects of the present application are: all processes of steel plate galvanizing can be completed on production line at one time, and multiple different steel coils can be continuously produced, which not only greatly improves the efficiency of steel plate galvanizing, but also ensures the quality of aluminized zinc steel plate.

Description

Technical Field

[0001] This invention belongs to the field of steel plate production technology, and specifically relates to a continuous production process and system for aluminized zinc steel plates. Background Technology

[0002] Steel is the material foundation of modern society, widely used in construction, manufacturing, transportation, and daily life. With its high strength, low cost, and ease of processing, steel supports a wide range of applications, from infrastructure to precision instruments. For convenient storage and transportation, and for easier subsequent processing, steel sheets are generally rolled into coils. The main consumption of steel products is due to corrosion; the manufacturing value of corroded and scrapped metal products is often much higher than the value of the metal itself. There are two main methods to address this problem: alloy corrosion protection and surface cladding corrosion protection. Because alloy corrosion protection is complex and expensive, surface cladding corrosion protection is currently the primary method, which involves forming a hot-dip aluminum-zinc coating on the steel surface. Under current technology, aluminum-zinc coating of coiled steel sheets is mostly carried out in stages, which is not only inefficient but also prevents continuous operation of each process, severely affecting the quality of the steel coil products. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention provides a continuous production process and system for aluminized zinc steel sheets.

[0004] This invention is achieved through the following technical solution: A continuous production process for aluminized zinc-coated steel sheets, characterized by the following steps: (1) After uncoiling the steel strip, weld it to the previous steel strip; (2) The steel belt enters the entrance loop and goes around several sections; (3) Clean the steel strip coming out of the inlet looper. The cleaning is divided into two parts. First, the steel strip is sprayed with alkaline solution. After the spraying is completed, it is brushed with alkaline solution. Then, the steel strip that has been brushed with alkaline solution is electrolytically cleaned. (4) The cleaned steel strip is heated in two stages: the first stage is open flame heating and the second stage is radiant heating. (5) The heated steel strip is rapidly cooled and then placed in the equalization buffer zone; (6) The steel strip is fed into the zinc pot. After the steel strip passes over the submerged roller, it is immersed in the zinc liquid for coating. After the zinc liquid is stabilized, the excess zinc liquid on the surface of the steel strip is scraped off. (7) Cool the steel strip by first performing upward vertical cooling and then downward vertical cooling; (8) The cooled steel strip is water quenched, and then squeezed dry and dried in sequence; (9) Perform finishing and wet straightening of the steel strip in sequence; (10) Coating the steel strip with chromic acid, then drying and cooling the steel strip, then coating the steel strip with resin, and then drying and cooling the steel strip again. (11) The steel strip enters the outlet looper and travels through several sections; (12) Apply electrostatic oil to the surface of the steel strip; (13) The steel strip is wound up.

[0005] Furthermore, in step (1), after welding, the excessively thick or irregular portions at the ends of the steel coil are cut off.

[0006] Furthermore, in step (3), the steel strip is subjected to two-stage electrolytic cleaning, then the steel strip is brushed with hot water, and after the hot water brushing is completed, the steel strip is rinsed with two-stage hot water.

[0007] Furthermore, in step (4), before heating the steel strip, the steel strip is first preheated using waste gas, and the second stage consists of radiative heating and radiative homogenization.

[0008] Furthermore, in step (5), thermal tension support is provided to the steel strip emerging from the equilibrium buffer.

[0009] Furthermore, in step (9), the coating thickness is measured before the steel strip is polished, the steel strip is squeezed dry after polishing, and the steel strip is squeezed dry and dried in sequence after wet stretching and straightening.

[0010] Furthermore, in step (13), the steel strip is slit before winding.

[0011] A continuous production system for aluminized zinc-coated steel sheets includes two uncoilers and two coilers located at both ends. The system is characterized by: a welding machine located behind each uncoiler; an inlet looper located behind the welding machine; a steel strip cleaning system located behind the inlet looper; a steel strip heating system located behind the steel strip cleaning system; the steel strip heating system consists of an open flame heating section, a radiant tube heating section, and a radiant tube insulation section; a zinc pot located behind the steel strip heating system; an air knife located above the zinc pot; an upward cooling system located above the air knife; a downward cooling system located behind the upward cooling system; a water quenching tank located below the downward cooling system; a finishing machine and a tension leveler located sequentially behind the water quenching tank; two vertically arranged chromic acid coating machines located behind the tension levelers; a resin coating machine located behind the chromic acid coating machines; an outlet looper located behind the resin coating machines; an electrostatic oiling machine located behind the outlet looper; and an outlet shearing machine located behind the electrostatic oiling machine.

[0012] Furthermore, a punching shear is installed at the rear of the welding machine.

[0013] Furthermore, the steel strip cleaning system includes, in sequence, an alkaline spray washing tank, an alkaline brush washing tank, a first electrolytic cleaning tank, a first electrolytic brush washing tank, a second electrolytic cleaning tank, a second electrolytic brush washing tank, a hot water brush washing tank, a first hot water rinsing tank, and a second hot water rinsing tank, with a drying air box located behind the second hot water rinsing tank.

[0014] Furthermore, an exhaust gas preheating section is provided in front of the open flame heating section.

[0015] Furthermore, a rapid cooling section, a balanced buffer section, and a thermal tension roller are sequentially provided between the steel strip heating system and the zinc pot.

[0016] Furthermore, the zinc pot is equipped with submersion rollers and stabilizing rollers from bottom to top.

[0017] Furthermore, the upward cooling system consists of a movable cooling fan box and several fixed cooling fans located above the movable cooling fan box, while the downward cooling system consists of several downward fixed cooling fans.

[0018] Furthermore, a water quenching tank squeezing roller is provided above the water quenching tank, and a water quenching tank drying box is provided above the water quenching tank squeezing roller.

[0019] Furthermore, a coating thickness gauge is installed between the water quenching tank and the finishing machine.

[0020] Furthermore, a straightening drying chamber is provided between the straightening machine and the chromic acid coating machine.

[0021] Furthermore, the chromic acid coating machine is equipped with a chromic acid drying chamber and an upward chromic acid cooling chamber above it, and a downward chromic acid cooling chamber is located behind the upward chromic acid cooling chamber. The resin coating machine is equipped with a resin drying and curing chamber and an upward resin cooling chamber above it, and a downward resin cooling chamber is located behind the upward resin cooling chamber.

[0022] The beneficial effects of this invention are: after the steel strip is uncoiled, it is cleaned and heated in sequence to complete the zinc coating on the surface. Then, after finishing, straightening and anti-rust oiling, it can be coiled up. These processes can be completed in one go on the production line, and multiple different steel coils can be produced continuously. This not only greatly improves the efficiency of galvanizing steel plates, but also ensures the quality of aluminum-zinc coated steel plates. Attached Figure Description

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Appendix Figure 1 This is a process flow diagram of the present invention; Appendix Figure 2 This is a system structure diagram of the present invention; Appendix Figure 3 This is a schematic diagram of the steel strip cleaning system of the present invention; Appendix Figure 4 This is a schematic diagram of the inlet loop structure of the present invention; Appendix Figure 5 This is a schematic diagram of the outlet looper structure of the present invention; In the diagram, 1 is the uncoiler, 2 is the coiler, 3 is the welding machine, 4 is the inlet looper, 5 is the strip cleaning system, 6 is the strip heating system, 7 is the open flame heating section, 8 is the radiant tube heating section, 9 is the radiant tube insulation section, 10 is the zinc pot, 11 is the air knife, 12 is the upward cooling system, 13 is the downward cooling system, 14 is the water quenching tank, 15 is the finishing machine, 16 is the tension leveler, 17 is the chromic acid coating machine, 18 is the resin coating machine, 19 is the outlet looper, 20 is the electrostatic oiling machine, 21 is the outlet shearing machine, 22 is the edge punching shear, 23 is the alkaline spray washing tank, 24 is the alkaline brush washing tank, 25 is the first electrolytic cleaning tank, 26 is the first electrolytic brush washing tank, 27 is the second electrolytic cleaning tank, 28 is the second electrolytic cleaning tank. 29 Hot water washing box, 30 First hot water rinsing box, 31 Second hot water rinsing box, 32 Drying air box, 33 Exhaust gas preheating section, 34 Rapid cooling section, 35 Equalization buffer section, 36 Thermal tension roller, 37 Submerged roller, 38 Stabilizing roller, 39 Moving cooling air box, 40 Fixed cooling air box, 41 Downward fixed cooling air box, 42 Water quenching tank squeeze roller, 43 Water quenching tank drying box, 44 Coating thickness gauge, 45 Straightening drying box, 46 Chromic acid drying box, 47 Upward chromic acid cooling box, 48 Downward chromic acid cooling box, 49 Resin drying and curing box, 50 Upward resin cooling box, 51 Downward resin cooling box. Detailed Implementation

[0025] The attached figure illustrates a specific embodiment of the present invention. This embodiment includes two uncoilers 1 and two coilers 2 located at both ends. A welding machine 3 is located behind the uncoilers 1, an inlet looper 4 is located behind the welding machine 3, a strip cleaning system 5 is located behind the inlet looper 4, and a strip heating system 6 is located behind the strip cleaning system 5. The strip heating system 6 consists of an open flame heating section 7, a radiant tube heating section 8, and a radiant tube insulation section 9. A zinc pot 10 is located behind the strip heating system 6, an air knife 11 is located above the zinc pot 10, and an upward cooling system 1 is located above the air knife 11. 2. A downward cooling system 13 is provided behind the upward cooling system 12. A water quenching tank 14 is provided below the downward cooling system 13. A finishing machine 15 and a tension leveling machine 16 are provided in sequence behind the water quenching tank 14. Two vertically arranged chromic acid coating machines 17 are provided behind the tension leveling machine 16. A resin coating machine 18 is provided behind the chromic acid coating machine 17. An outlet looper 19 is provided behind the resin coating machine 18. An electrostatic oiling machine 20 is provided behind the outlet looper 19. An outlet shearing machine 21 is provided behind the electrostatic oiling machine 20.

[0026] A punching shear 22 is installed behind the welding machine 3 to cut off the excessively thick or irregular parts at the end of the steel coil, ensuring that the steel strip meets the set requirements in each process and avoiding defective products.

[0027] The steel strip cleaning system 5 includes an alkaline spray washing tank 23, an alkaline brush washing tank 24, a first electrolytic cleaning tank 25, a first electrolytic brush washing tank 26, a second electrolytic cleaning tank 27, a second electrolytic brush washing tank 28, a hot water brush washing tank 29, a first hot water rinsing tank 30, and a second hot water rinsing tank 31 arranged in sequence. A drying air box 32 is provided behind the second hot water rinsing tank 31.

[0028] The steel strip first enters the alkaline spray cleaning tank 23. Under the spray of high-pressure alkaline cleaning solution, the adsorption force of grease on the surface of the steel strip is rapidly reduced, and a large amount of surface oil is emulsified and removed in the degreasing solution. It can also loosen and remove some iron powder, dust and other dirt.

[0029] In the alkaline washing tank 24, the steel strip is further cleaned by the combined action of spraying and brushing rollers, removing heavy grease and a large amount of solid impurities such as iron powder and dust from the surface of the steel strip. This improves the cleaning effect and prevents solid impurities from being electrodeposited on the electrode surface under the action of the electric field in the electrolysis section, thus avoiding the formation of a large amount of sludge.

[0030] In the first electrolytic cleaning tank 25, the first electrolytic brushing tank 26, the second electrolytic cleaning tank 27, and the second electrolytic brushing tank 28, two sets of continuous electrolytic cleaning and electrolytic brushing are performed. Through the combined effects of the high-voltage H2 (or O2) generated by electrolysis and the emulsifying effect of the alkaline cleaning solution, stubborn oil stains, slag, rust, and other impurities on the steel strip surface are removed, thus achieving the cleaning purpose. During electrolytic cleaning and brushing, the polarity of the electrodes can be automatically changed, realizing self-cleaning of the electrodes and preventing the deposition of dust particles and iron filings on the electrodes.

[0031] In the hot water washing tank 29, iron filings and dust on the surface of the steel strip are further removed by mechanical brushing, improving the cleaning effect of electrolytic cleaning.

[0032] In the continuous first hot water rinsing tank 30 and second hot water rinsing tank 31, the residual cleaning fluid on the surface of the steel belt is removed, and the direction of water replenishment for rinsing is opposite to the direction of steel belt running.

[0033] An iron powder filter device was installed in the above-mentioned alkaline washing and electrolytic washing tanks, which improved the degreasing efficiency and extended the service life of the degreasing agent.

[0034] After cleaning, a test is conducted using the wiping method. If the wiping paper does not turn black after wiping, the desired effect has been achieved.

[0035] An exhaust gas preheating section 33 is provided in front of the open flame heating section 7, which not only improves heating efficiency but also enables the reuse of high-temperature exhaust gas in the workshop, reducing energy consumption.

[0036] Combining open flame and radiant heating methods allows for more efficient heating of the steel strip to the predetermined temperature, and the high temperature of the open flame section can burn off any impurities remaining on the steel strip. The radiant tube allows for better control of the oxygen content, maximizing the reduction of iron oxide to pure iron and improving the surface adhesion of the strip.

[0037] Between the steel strip heating system 6 and the zinc pot 10, there is a rapid cooling section 34, a leveling buffer section 35, and a thermal tension roller 36 arranged sequentially. The leveling buffer section 35 eliminates core heat in the steel strip during thick plate production, ensuring uniform temperature across the entire cross-section. During thin plate production and furnace start-up, it heats the steel strip to maintain the correct entry temperature into the zinc pot, ensuring a good coating and reducing the amount of defective products during furnace start-up. The thermal tension roller 36 ensures the high tension required in the zinc pot area, facilitating the stability of the steel strip as it passes through the air knife.

[0038] Inside the zinc pot 10, from bottom to top, are submerged rollers 37 and stabilizing rollers 38. Submerged rollers 37 ensure the steel strip is completely immersed in the molten zinc, preventing any gaps in the coating. The nozzle of the air knife 11 is located above the zinc pot 10. The airflow from the nozzle scrapes off excess molten zinc from the steel strip surface, thus controlling the coating thickness. By adjusting the air pressure and nozzle position, the desired coating thickness can be achieved. The stabilizing rollers 38 keep the steel strip on a fixed running line after exiting the zinc pot, ensuring stable operation of the steel strip in the air knife zone and guaranteeing the uniformity and stability of the coating.

[0039] The upward cooling system 12 consists of a movable cooling fan box 39 and several fixed cooling fan boxes 40 located above the movable cooling fan box 39, while the downward cooling system 13 consists of several downward fixed cooling fan boxes 41. By setting up the upward cooling system 12 and the downward cooling system 13, the steel strip can be rapidly cooled to below 280°C, ensuring the cooling effect while saving workshop space and making the aluminized zinc production line more continuous and smooth.

[0040] A water quenching tank 14 is equipped with a water quenching tank squeeze roller 42, and a water quenching tank drying box 43 is equipped above the water quenching tank squeeze roller 42. The water quenching tank 14 further reduces the temperature of the steel strip. After water quenching, squeezing and drying, the temperature of the steel strip can be reduced to below 40°C, which provides conditions for the smooth progress of the next finishing process.

[0041] A coating thickness gauge 44 is installed between the water quenching tank 14 and the finishing machine 15. Before finishing, the coating thickness is monitored online in real time so that the steel strip feed speed and air knife scraping thickness can be adjusted in time during the production process, thereby ensuring that the coating thickness on the steel strip surface meets the production requirements.

[0042] During finishing, a finishing liquid spraying system is configured to achieve wet finishing, further improving the surface smoothness. A high-pressure water spraying system is also provided to clean residual particles on the surface of the work roller and support roller, reducing the risk of surface defects.

[0043] The finishing machine 15 can eliminate yield plateaus, adjust the surface roughness of aluminized zinc steel strip, flatten zinc spangles, and improve the straightness of the steel strip. The finishing machine 15 then removes the finishing liquid adhering to the steel strip surface using squeeze rollers. After finishing, the steel strip passes through the tension leveler 16 again, further improving its straightness.

[0044] A straightening and drying chamber 45 is provided between the straightening machine 16 and the chromic acid coating machine 17.

[0045] The chromic acid coating machine 17 is equipped with a chromic acid drying box 46 and an upward chromic acid cooling box 47 above it, and a downward chromic acid cooling box 48 is provided behind the upward chromic acid cooling box 47. The resin coating machine 18 is equipped with a resin drying and curing box 49 and an upward resin cooling box 50 above it, and a downward resin cooling box 51 is provided behind the upward resin cooling box 50.

[0046] After passing through two chromic acid coating machines 17, a passivation film is applied to the surface of the steel strip. After passing through a resin coating machine 18, an anti-fingerprint film is applied to the surface of the steel strip. After drying and cooling, the passivation film and the anti-fingerprint film adhere more firmly and evenly to the surface of the steel strip.

[0047] The exit looper 19 ensures the normal operation of the process section when the coil is unloaded or the steel strip surface is inspected. At the same time, the inlet looper 4 ensures the normal operation of the process section when the coil is changed at the inlet section. In this way, continuous production can be achieved whether the steel coil is changed at the inlet section or the exit section.

[0048] The export shearing machine 21 only operates when the steel strip needs to be cut or sampled.

[0049] During annealing, the steel strip outlet temperature of the open flame heating section 7 is controlled at 500-700℃, the steel strip outlet temperature of the radiant tube heating section 8 is controlled at 550-780℃, and the temperature of the heating chamber where the hot tension roller 36 is located is controlled at 560℃.

Claims

1. A continuous production process for aluminized zinc-coated steel sheets, characterized by: Includes the following steps: (1) After uncoiling the steel strip, weld it to the previous steel strip and cut off the excessively thick or irregular parts at the end of the steel coil; (2) The steel belt enters the entrance loop and goes around several sections; (3) Clean the steel strip coming out of the inlet looper. The cleaning is divided into two parts. First, the steel strip is sprayed with alkaline solution. After the spraying is completed, it is brushed with alkaline solution. Then, the steel strip that has been brushed with alkaline solution is electrolytically cleaned. (4) The cleaned steel strip is heated in two stages: the first stage is open flame heating and the second stage is radiant heating. (5) The heated steel strip is rapidly cooled and then enters the equalization buffer zone to provide thermal tension support to the steel strip coming out of the equalization buffer zone; (6) The steel strip is fed into the zinc pot. After the steel strip passes over the submerged roller, it is immersed in the zinc liquid for coating. After the zinc liquid is stabilized, the excess zinc liquid on the surface of the steel strip is scraped off. (7) Cool the steel strip by first performing upward vertical cooling and then downward vertical cooling; (8) The cooled steel strip is water quenched, and then squeezed dry and dried in sequence; (9) Perform finishing and wet straightening of the steel strip in sequence; (10) Coating the steel strip with chromic acid, then drying and cooling the steel strip, then coating the steel strip with resin, and then drying and cooling the steel strip. (11) The steel strip enters the outlet looper and travels through several sections; (12) Apply electrostatic oil to the surface of the steel strip; (13) Cut the steel strip and then wind and rewind it.

2. The continuous production process for aluminized zinc-coated steel sheets according to claim 1, characterized in that: in In step (3), the steel strip is subjected to two-stage electrolytic cleaning, and then the steel strip is brushed with hot water. After the hot water brushing is completed, the steel strip is rinsed with hot water in two stages.

3. The continuous production process for aluminized zinc-coated steel sheets according to claim 1, characterized in that: in In step (4), before heating the steel strip, the steel strip is first preheated with waste gas, and the second stage consists of radiation heating and radiation homogenization.

4. The continuous production process for aluminized zinc-coated steel sheets according to claim 1, characterized in that: in In step (9), the coating thickness is measured before the steel strip is polished, the steel strip is squeezed dry after polishing, and the steel strip is squeezed dry and dried in sequence after wet straightening.

5. A continuous production system for aluminized zinc-coated steel sheets, comprising two uncoilers (1) and two coilers (2) located at both ends, characterized in that: A welding machine (3) is located behind the uncoiler (1), an inlet looper (4) is located behind the welding machine (3), a steel strip cleaning system (5) is located behind the inlet looper (4), a steel strip heating system (6) is located behind the steel strip cleaning system (5), and a steel strip heating system (6) is located behind the steel strip heating system (5). The steel strip heating system (6) consists of an open flame heating section (7), a radiant tube heating section (8), and a radiant tube insulation section (9). A zinc pot (10) is located behind the steel strip heating system (6), an air knife (11) is located above the zinc pot (10), and an upward cooling system (12) is located above the air knife (11). 2) A downward cooling system (13) is provided at the rear. A water quenching tank (14) is provided below the downward cooling system (13). A finishing machine (15) and a straightening machine (16) are provided in sequence behind the water quenching tank (14). Two vertically arranged chromic acid coating machines (17) are provided behind the straightening machine (16). A resin coating machine (18) is provided behind the chromic acid coating machine (17). An outlet looper (19) is provided behind the resin coating machine (18). An electrostatic oiling machine (20) is provided behind the outlet looper (19). An outlet shearing machine (21) is provided behind the electrostatic oiling machine (20).

6. The continuous production system for aluminized zinc-coated steel sheets according to claim 5, characterized in that: A punching shear (22) is installed behind the welding machine (3).

7. The continuous production system for aluminized zinc-coated steel sheets according to claim 5, characterized in that: The steel strip cleaning system (5) includes an alkaline spray washing box (23), an alkaline brush washing box (24), a first electrolytic cleaning box (25), a first electrolytic brush washing box (26), a second electrolytic cleaning box (27), a second electrolytic brush washing box (28), a hot water brush washing box (29), a first hot water rinsing box (30), and a second hot water rinsing box (31), with a drying air box (32) located behind the second hot water rinsing box (31).

8. The continuous production system for aluminized zinc-coated steel sheets according to claim 5, characterized in that: An exhaust gas preheating section (33) is provided in front of the open flame heating section (7). A rapid cooling section (34), a balanced buffer section (35) and a thermal tension roller (36) are provided between the steel strip heating system (6) and the zinc pot (10). A submerged roller (37) and a stabilizing roller (38) are provided in the zinc pot (10) from bottom to top.

9. The continuous production system for aluminized zinc-coated steel sheets according to claim 5, characterized in that: The upward cooling system (12) consists of a movable cooling air box (39) and several fixed cooling air boxes (40) located above the movable cooling air box (39). The downward cooling system (13) consists of several downward fixed cooling air boxes (41). A water quenching tank squeezing roller (42) is provided above the water quenching tank (14). A water quenching tank drying box (43) is provided above the water quenching tank squeezing roller (42). A coating thickness gauge (44) is provided between the water quenching tank (14) and the finishing machine (15).

10. The continuous production system for aluminized zinc-coated steel sheets according to claim 5, characterized in that: A straightening drying box (45) is provided between the straightening machine (16) and the chromic acid coating machine (17). A chromic acid drying box (46) and an upward chromic acid cooling box (47) are provided above the chromic acid coating machine (17). A downward chromic acid cooling box (48) is provided behind the upward chromic acid cooling box (47). A resin drying and curing box (49) and an upward resin cooling box (50) are provided above the resin coating machine (18). A downward resin cooling box (51) is provided behind the upward resin cooling box (50).

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