Structure for improving air tightness of continuous annealing furnace quick cooling section under high hydrogen mode

Abstract

The utility model belongs to the strip production and equipment technical field especially relates to a structure of improving air tightness under high hydrogen mode of continuous annealing furnace fast cooling section, including sealing roll chamber outer shell, roller, sealing roll chamber outer shell lining firebrick, roller bottom is sealedly connected with graphite sealing washer, and the bottom and both ends of graphite sealing washer are fixed through the castable, the both ends of castable and sealing roll chamber outer shell lining firebrick are provided with backing plate, and the backing plate and sealing roll chamber outer shell lining firebrick are filled with microporous heat insulating board, and the gap of each part of upper end, lateral wall and bottom in sealing roll chamber is filled with ceramic fiber, the main purpose of the utility model is to guarantee the stability of fast cooling section sealing roll chamber structure, and improve the sealing property in the roll chamber, prevent excessive hydrogen medium overflow to slow cooling section and overaging section, save the consumption of hydrogen energy, guarantee the safety of unit.

Description

Technical Field

[0001] This utility model belongs to the field of plate and strip production and equipment technology, and in particular relates to a structure for improving air tightness in the high hydrogen mode of the rapid cooling section of the continuous annealing furnace. Background Technology

[0002] The increasing market demand for phase transformation high-strength steels, such as cold-rolled duplex steel, which require high cooling rates, has significantly impacted the stable operation of continuous annealing units in the cold rolling process, particularly placing higher demands on the stable control of the rapid cooling section. Furthermore, due to the high permeability of hydrogen, the safety requirements in this area are also relatively high.

[0003] Currently, the rapid cooling section of continuous annealing production lines all adopt a four-roller sealing structure. The existing rapid cooling section sealing roller chamber structure and material design are unreasonable. This sealing method is simple in structure and low in cost, resulting in poor sealing and isolation between the rapid cooling section and other furnace chambers. Sometimes, the hydrogen content at the connection channel exceeds 8%, triggering the backflushing procedure and halting normal production. The only solution is to stop the machine and replace the sealing strips to restart operation. Furthermore, when the rapid cooling section is put into high-hydrogen mode, hydrogen diffusion to other sections is severe, especially in the slow cooling section. When the rapid cooling section has a high hydrogen input of 30%, the hydrogen content in the slow cooling section reaches 18%, causing significant energy waste. Moreover, hydrogen diffusion caused by poor sealing poses a significant safety hazard. In addition, to ensure stable operation in the rapid cooling section area, the sealing strips need to be replaced regularly. The short replacement cycle and high replacement frequency result in substantial cost. Utility Model Content

[0004] This invention addresses the frequent hydrogen overflow phenomenon in the rapid cooling section of continuous annealing mills producing cold-rolled duplex steel when high hydrogen levels are introduced. It designs a sealing structure and construction method to prevent this from occurring. The main purpose of this invention is to ensure the stability of the sealed roller chamber structure in the rapid cooling section, improve the sealing performance within the roller chamber, prevent excessive hydrogen from overflowing into the slow cooling and over-aging sections, save hydrogen energy consumption, and ensure the safety of the unit.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes a sealed roller chamber shell, a roller, and a refractory brick lining inside the sealed roller chamber shell. The bottom of the roller is sealed to a graphite gasket, and the bottom and both ends of the graphite gasket are fixed by castable. A backing plate is provided between the two ends of the castable and the refractory brick lining inside the sealed roller chamber shell. A microporous insulation board is filled between the backing plate and the refractory brick lining inside the sealed roller chamber shell. The gaps in the upper part, side wall, and bottom of the sealed roller chamber are filled with ceramic fiber.

[0007] The bottom step of the backing plate is supported by square tubes.

[0008] The backing board is an asbestos-free lightweight calcium silicate insulation backing board.

[0009] The cross-sectional dimensions of the square tube are (40-50)mm × (40-50)mm.

[0010] The graphite gaskets are inclined downwards to both sides, and the middle position of the two graphite gaskets is the strip running channel. Protective pipes are also installed on both sides of the strip running channel, and bearings are provided at both ends of the protective pipes.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1) After the implementation of this utility model, when the high-hydrogen mode is used in the rapid cooling section, with a high hydrogen input of 30% in the rapid cooling section, the hydrogen content in the slow cooling section drops to below 6%. This not only saves a large amount of hydrogen, the energy medium, but also eliminates the safety hazards associated with it. At the same time, it also saves production costs for enterprises, achieving the ultimate goal of cost reduction and efficiency improvement.

[0013] 2) After the implementation of this utility model, the sealing structure of the rapid cooling section is stable and has a long service life, and does not need to be replaced frequently, thus avoiding the waste caused by cost consumption. Attached Figure Description

[0014] Figure 1 This is the front view of the sealing roller chamber.

[0015] Figure 2 yes Figure 1 AA view.

[0016] Figure 3 yes Figure 2 A magnified view of point D.

[0017] Figure 4 yes Figure 2 BB view.

[0018] Figure 5 yes Figure 4 A magnified view of point C.

[0019] In the diagram: 1. Steel plate; 2. Ceramic fiber; 3. Microporous insulation board; 4. Castable refractory; 5. Graphite gasket; 6. Backing plate; 7. Roller; 8. Square tube; 9. Protective tube. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0021] The main function of the rapid cooling section of a continuous annealing furnace is to cool the strip steel at a high rate to obtain the required metallographic structure, and the temperature of the cooled strip steel meets the requirements for entering the over-aging section. Generally, the rapid cooling section of a continuous annealing furnace mainly includes an inlet sealing roller chamber, an upward section furnace chamber, an outlet sealing roller chamber, and a downward section furnace chamber. Three sets of circulating cooling fans and cooling air boxes are installed in the upward section furnace chamber. The sealing roller chamber consists of upper and lower parts, with basically the same structural configuration. This utility model mainly designs the sealing structure and construction method of the sealing roller chamber in the rapid cooling section of a continuous annealing furnace, ensuring the stability of the sealing structure, increasing sealing performance, saving hydrogen energy consumption, and ensuring the safety of the unit. The specific structure and construction method are as follows:

[0022] See as 1- Figure 5 A structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes a sealed roller chamber shell, a roller 7, and a refractory brick lining inside the sealed roller chamber shell. The bottom of the roller 7 is sealed to a graphite sealing gasket 5. The bottom and both ends of the graphite sealing gasket 5 are fixed by a castable 4. A backing plate 6 is provided between the two ends of the castable 4 and the refractory brick lining inside the sealed roller chamber shell. A microporous insulation board 3 is filled between the backing plate 6 and the refractory brick lining inside the sealed roller chamber shell. The gaps in the upper part, side wall and bottom of the sealed roller chamber are filled with ceramic fiber 2.

[0023] The bottom step of the backing plate 6 is supported by square tubes 8.

[0024] Backing board 6 is an asbestos-free lightweight calcium silicate insulation backing board.

[0025] The cross-sectional dimensions of square tube 8 are 40mm × 40mm.

[0026] The opening between the two graphite gaskets 5 is 1890mm×200mm. The graphite gaskets 5 are inclined downwards to both sides. The middle position of the two graphite gaskets 5 is the strip steel running channel. Protective pipes 9 are also installed on both sides of the strip steel running channel. Bearings are provided at both ends of the protective pipes 9 so that they can rotate.

[0027] The graphite gasket 5 is installed at an angle, which increases the distance between the roller and the graphite gasket 5 when the sealing roller is open, thus avoiding continuous contact between the roller and the graphite gasket 5 when it is not in operation, which would shorten the service life of the graphite gasket 5.

[0028] The protective tube 9 is located on both sides. When the strip is unstable (due to strip shape difference or left-right shaking of the strip perpendicular to the threading line), the surface of the strip will first come into contact with the protective tube 9. The protective tube 9 is designed to be rotatable to eliminate stress and avoid damage to related equipment.

[0029] A construction method for improving the airtightness of a structure in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes the following steps:

[0030] 1) Remove the 4 rollers 7, each side drawer and pipe of the sealing roller chamber, and open the side door to form a passage; remove the inner heat insulation board and door reinforcement board around the sealing roller chamber.

[0031] 2) After removing the pipes on the inner and outer walls at the bottom of the sealing roller chamber, weld 5mm thick steel plates 1 to seal the holes; remove the panel strip, reinforcing ribs and threaded connecting blocks behind the door; then weld the drawer cover plate at the point where the drawer was removed.

[0032] 3) At the new elevation point, i.e., 1093mm from the top of the sealing roller chamber, re-weld the strip and reinforcing ribs; and lay the inner lining and protective plate.

[0033] 4) Install the casting material 4 that is compatible with the internal structure of the sealing roller chamber housing.

[0034] 5) Install the graphite sealing gasket 5 and the backing plate 6. At both ends of the sealing roller chamber, glue the 40mm×40mm square tube 8 supporting the backing plate to the castable 4 on both sides.

[0035] 6) Laying the inner lining: Insert the microporous insulation board 3 (20mm thick) along the backing plate 6 between the castable 4 and the refractory brick lining of the sealing roller chamber shell; further ensure the insulation of the metal shell part; fill all gaps in the inner lining caused by cutting and other factors with ceramic fiber 2.

[0036] 7) Reinstall the sealing rollers and install protective pipes on both sides of the strip running path. Reinstall previously removed components, such as doors and rollers.

[0037] 8) Visually inspect to ensure proper tangential contact between the graphite gasket 4 and the roller 7 along the entire length.

[0038] Taking the production of duplex steel on a 2150 continuous annealing unit in a domestic cold rolling mill as an example, this invention describes the treatment of the sealed roller chamber of the rapid cooling section of the 2150 continuous annealing furnace according to its structure and method, utilizing the unit's annual maintenance cycle. After maintenance, when the continuous annealing unit is used to produce duplex steel (grade DP590), the rapid cooling section uses a high-hydrogen mode, and the hydrogen content in each section of the furnace is monitored in real time on the secondary HMI operation screen. The operation screen shows that the hydrogen content in zones 2, 3, and 4 of the rapid cooling section is approximately 44%, 46%, and 46%, respectively. At this time, the hydrogen content in the adjacent slow cooling section (zone 2) and over-aging section (zone 1) is approximately 4% and 2%, respectively.

[0039] In addition to providing a better sealing effect, this invention also prevents the strip from rubbing against the graphite gaskets 5 on both sides when the strip is operating under unstable conditions (such as strip deviation, strip shape differences, or strip vibration caused by a large amount of hydrogen input to the fast cooling section fan). Under normal operating conditions, when high hydrogen is introduced into the fast cooling section, the two sets of sealing rollers move towards the center line and work in close contact with the strip surface. When the strip becomes unstable, it will first contact the protective pipe 9 device to avoid rubbing against the graphite gaskets 5 on both sides.

Claims

1. A structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace, comprising a sealed roller chamber shell, rollers, and a refractory brick lining the sealed roller chamber shell, characterized in that, The bottom of the roller is sealed to a graphite gasket. The bottom and both ends of the graphite gasket are fixed by a castable. A backing plate is provided between the two ends of the castable and the refractory brick lining of the sealing roller chamber. A microporous insulation board is filled between the backing plate and the refractory brick lining of the sealing roller chamber. The gaps in the upper part, side wall and bottom of the sealing roller chamber are filled with ceramic fiber.

2. The structure for improving gas tightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace according to claim 1, characterized in that, The bottom step of the backing plate is supported by square tubes.

3. The structure for improving gas tightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace according to claim 1, characterized in that, The backing board is an asbestos-free lightweight calcium silicate insulation backing board.

4. The structure for improving gas tightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace according to claim 2, characterized in that, The cross-sectional dimensions of the square tube are (40-50) mm × (40-50) mm.

5. The structure for improving gas tightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace according to claim 1, characterized in that, The graphite gaskets are inclined downwards to both sides, and the middle position of the two graphite gaskets is the strip running channel. Protective pipes are also installed on both sides of the strip running channel, and bearings are provided at both ends of the protective pipes.

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