Structure and method for improving air tightness of rapid cooling section of continuous annealing furnace in high-hydrogen mode

Abstract

The invention belongs to the technical field of plate and strip production and equipment, and particularly relates to a structure and method for improving air tightness of a rapid cooling section of a continuous annealing furnace in a high-hydrogen mode, the structure comprises a sealing roller chamber shell, a roller and sealing roller chamber shell lining refractory bricks, the bottom of the roller is in sealing connection with a graphite sealing gasket, and the bottom and the two ends of the graphite sealing gasket are fixed through castable; back lining plates are arranged between the two ends of the castable and the sealing roller chamber shell lining refractory bricks, the positions between the back lining plates and the sealing roller chamber shell lining refractory bricks are filled with micropore heat insulation plates, and gaps of the upper end, the side wall and the bottom in the sealing roller chamber are filled with ceramic fibers. The invention mainly aims to ensure the stability of the sealing roller chamber structure of the rapid cooling section, improve the sealing performance in the roller chamber, prevent excessive hydrogen medium from overflowing to the slow cooling section and the overaging section, save the consumption of hydrogen energy and ensure the safety of a unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of strip production and equipment, and particularly relates to a structure and method for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace. Background Art

[0002] In recent years, with the increasing market demand for phase transformation high-strength steels such as cold-rolled dual-phase steels that require a relatively high cooling rate, it has had a serious impact on the stable operation of continuous annealing units in the cold-rolling process, especially posing higher requirements for the stable control of the rapid cooling section. Moreover, due to the strong permeability of hydrogen, relatively high safety requirements are also imposed on this area.

[0003] Currently, four-roll sealing rollers are used in the rapid cooling section of continuous annealing production lines. The existing sealing roller chamber structure and material design in the rapid cooling section are unreasonable. This sealing method has a simple structure and low cost. As a result, the sealing and isolation effect between the rapid cooling section and other furnace chambers is poor. Sometimes, the hydrogen content at the connection channel exceeds 8%, triggering the anti-purging program, making normal production impossible, and it can only be restarted by shutting down and replacing the sealing strip. Moreover, when the high-hydrogen mode is put into use in the rapid cooling section, it diffuses severely to other sections. Especially in the slow cooling section, when 30% of high hydrogen is input in the rapid cooling section, the hydrogen content in the slow cooling section reaches 18%, resulting in a great waste of energy. In addition, the hydrogen diffusion caused by poor airtightness poses a great potential safety hazard. Additionally, to ensure the stable operation of the rapid cooling section area, the sealing strip needs to be replaced regularly. The short replacement cycle and frequent replacement frequency result in a large cost consumption. Summary of the Invention

[0004] In view of the phenomenon of hydrogen overflow that often occurs in the rapid cooling section when the continuous annealing unit produces cold-rolled dual-phase steel with high hydrogen input, the present invention designs a sealing structure and construction method to avoid this situation. The main purpose of the invention is to ensure the stability of the sealing roller chamber structure in the rapid cooling section, improve the airtightness inside the roller chamber, prevent excessive hydrogen medium from overflowing to the slow cooling section and the over-aging section, save the consumption of hydrogen energy, and ensure the safety of the unit.

[0005] To achieve the above object, the present invention is realized by adopting the following technical solutions:

[0006] A structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes a sealing roller chamber outer shell, rollers, and a refractory brick lining inside the sealing roller chamber outer shell. The bottom of the roller is sealed and connected to a graphite sealing gasket. The bottom and both ends of the graphite sealing gasket are fixed by casting material. A backing plate is arranged between both ends of the casting material and the refractory brick lining inside the sealing roller chamber outer shell. A micro-porous heat-insulating board is filled between the backing plate and the refractory brick lining inside the sealing roller chamber outer shell. The gaps at the upper end, side wall, and bottom of the sealing roller chamber are filled with ceramic fiber.

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

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

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

[0010] The graphite gasket slopes downward in both side directions. The middle position between the two graphite gaskets is a strip steel running channel. Protection pipes are also installed on both sides of the strip steel running channel, and bearings are provided at both ends of the protection pipes.

[0011] A construction method for a structure to improve airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes the following method steps:

[0012] 1) Remove 4 rollers, each side drawer and pipes in the seal roll chamber, open the side door to form a channel; remove the inner lining heat insulation board and door reinforcement board around the seal roll chamber.

[0013] 2) After removing the pipes on the inner and outer walls at the bottom of the seal roll chamber, weld steel plates at each place to seal the holes; remove the strip steel, reinforcing ribs and threaded connection blocks behind the door; then weld the drawer cover plate. Since the drawer structure is cancelled, weld the cover plate to ensure the closure of the overall seal roll chamber.

[0014] 3) At the new elevation point, that is, 1050 - 1100 mm away from the top of the seal roll chamber, re-weld the strip steel and reinforcing ribs; and lay the inner lining and protection board.

[0015] 4) Install the castable suitable for the internal structure of the seal roll chamber housing.

[0016] 5) Install the graphite gasket and the backing plate. At both ends of the seal roll chamber, glue the 40 mm × 40 mm square tube supporting the backing plate to the castable on both sides.

[0017] 5) Install the graphite gasket and the backing plate. At both ends of the seal roll chamber, glue the square tube supporting the backing plate to the castable on both sides.

[0018] 6) Lay the inner lining: Insert the microporous thermal insulation board along the backing plate between the castable and the refractory brick of the inner lining of the seal roll chamber housing to further ensure the heat insulation of the metal housing part; fill all gap areas caused by factors such as cutting in the inner lining with ceramic fiber.

[0019] 7) Reinstall the seal roll, and install protection pipes on both sides of the strip steel running channel. Reinstall the previously removed components. Such as: doors and rollers, etc.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1) After the implementation of the present invention, when the high-hydrogen mode is put into use in the rapid cooling section, when 30% of high-hydrogen is input in the rapid cooling section, the hydrogen content in the slow cooling section drops below 6%. This not only saves a large amount of energy medium hydrogen, but also eliminates the resulting unsafe factors. At the same time, it also saves production costs for the enterprise and achieves the ultimate goal of cost reduction and efficiency increase.

[0022] 2) After the implementation of the present invention, the sealing structure in the rapid cooling section area is stable and has a long service life, without the need for frequent replacement, avoiding waste caused by cost consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the front view of the sealing roller chamber.

[0024] Figure 2 is Figure 1 the view in the direction of A-A of

[0025] Figure 3 is Figure 2 the enlarged view of point D of

[0026] Figure 4 is Figure 2 the view in the direction of B-B of

[0027] Figure 5 is Figure 4 the enlarged view of point C of

[0028] In the figure: 1, steel plate; 2, ceramic fiber; 3, microporous insulation board; 4, castable; 5, graphite gasket; 6, backing plate; 7, roller; 8, square pipe, 9, protection pipe. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0030] The main function of the rapid cooling section of the continuous annealing furnace is to cool the strip at a relatively high cooling rate to obtain the required metallographic structure, and the temperature of the cooled strip meets the requirements for entering the overaging section. Generally, the rapid cooling section of the continuous annealing furnace mainly includes an inlet sealing roller chamber, an upper furnace chamber, an outlet sealing roller chamber, and a lower furnace chamber. Three groups of circulating cooling fans and cooling air boxes are installed in the upper furnace chamber. The sealing roller chamber structure consists of two parts, upper and lower, and the roller chamber structure configurations are basically the same. The present invention mainly designs the sealing structure and its construction method of the sealing roller chamber in the rapid cooling section of the continuous annealing furnace, ensuring the stability of the sealing structure of the sealing roller chamber in the rapid cooling section of the continuous annealing furnace, increasing the sealing performance, saving the consumption of hydrogen energy, and ensuring the safety of the unit. The specific structure and construction method steps are as follows:

[0031] See Figure 1- Figure 5, A structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace, including the outer shell of the sealing roller chamber, roller 7, and refractory bricks lined inside the outer shell of the sealing roller chamber. The bottom of the roller 7 is hermetically connected to the graphite gasket 5. The bottom and both ends of the graphite gasket 5 are fixed by casting material 4. A backing plate 6 is arranged between both ends of the casting material 4 and the refractory bricks lined inside the outer shell of the sealing roller chamber. A microporous insulating board 3 is filled between the backing plate 6 and the refractory bricks lined inside the outer shell of the sealing roller chamber. The gaps at the upper end, side wall, and bottom of the sealing roller chamber are filled with ceramic fiber 2.

[0032] The step at the bottom of the backing plate 6 is supported by arranging a square tube 8.

[0033] The backing plate 6 is an asbestos-free lightweight calcium silicate insulating backing plate.

[0034] The cross-sectional dimension of the square tube 8 is 40mm×40mm.

[0035] The opening size between two graphite gaskets 5 is 1890mm×200mm. The graphite gaskets 5 are inclined downward in both side directions. The middle position between the two graphite gaskets 5 is the strip steel running channel. Protection tubes 9 are also installed on both sides of the strip steel running channel. Bearings are arranged at both ends of the protection tubes 9 and can rotate.

[0036] The graphite gasket 5 is installed in an inclined plane, which increases the distance between the roller and the graphite gasket 5 when the sealing roller is opened, avoiding the continuous contact between the roller and the graphite gasket 5 in the non-working state and shortening the service life of the graphite gasket 5.

[0037] The protection tube 9 devices are provided on both the left and right. When the strip steel is in an unstable state (the strip steel shape is poor or the strip steel jitters left and right in the direction perpendicular to the threading line), the surface of the strip steel will first contact the protection tube 9, and the protection tube 9 is designed to be rotatable to eliminate stress and avoid damage to related equipment.

[0038] A construction method for a structure for improving airtightness in the high-hydrogen mode of the rapid cooling section of a continuous annealing furnace includes the following method steps:

[0039] 1) Remove 4 rollers 7, each side drawer, and tubes in the sealing roller chamber, and open the side door to form a channel; remove the inner lining heat insulation board and door reinforcement board around the sealing roller chamber.

[0040] 2) After removing the tubes on the inner and outer walls at the bottom of the sealing roller chamber, weld 5mm thick steel plates 1 at each place to seal the holes; remove the strip steel, stiffeners, and threaded connection blocks behind the door; then weld a drawer cover plate at the place where the drawer is removed.

[0041] 3) At the new elevation point, that is, 1093mm away from the top of the sealing roller chamber, re-weld the strip steel and stiffeners; and lay the inner lining and protection plate.

[0042] 4) Install the castable 4 that adapts to the internal structure of the sealing roller chamber housing.

[0043] 5) Install the graphite gasket 5 and the backing plate 6. At both ends of the sealing roller chamber, glue the 40mm×40mm square tube 8 that supports the backing plate to the castable 4 on both sides.

[0044] 6) Lay the inner lining: Insert the micro-porous insulation board 3 (with a thickness of 20mm) along the backing plate 6 between the castable 4 and the refractory brick on the inner lining of the sealing roller chamber housing; further ensure the heat insulation of the metal housing part; fill all the gap areas on the inner lining caused by factors such as cutting with ceramic fiber 2.

[0045] 7) Reinstall the sealing roller and install the protection pipes on both sides of the strip running channel. Reinstall the previously removed components. Such as: doors and rollers, etc.

[0046] 8) Through visual inspection, ensure correct tangential contact between the graphite gasket 4 and the roller 7 in the entire length direction.

[0047] Taking the production of dual-phase steel by the continuous annealing 2150 unit in a domestic cold rolling mill as an example, during the annual maintenance period of the unit, the sealing roller chamber of the rapid cooling section of the 2150 continuous annealing furnace is processed according to the structure and method of the present invention. After the overhaul, when arranging the production of dual-phase steel (steel grade DP590) in this continuous annealing unit, the high-hydrogen mode is used in the rapid cooling section, and at the same time, the hydrogen content in each section of the furnace is monitored in real time on the secondary HMI operation screen. It can be seen from the operation screen that the hydrogen contents in zones 2, 3, and 4 of the rapid cooling section are approximately 44%, 46%, and 46% respectively. At this time, the hydrogen contents in zone 2 of the slow cooling section and zone 1 of the over-aging section adjacent to the rapid cooling section are approximately 4% and 2% respectively.

[0048] In addition to having a better sealing effect, the present invention can also avoid rubbing against the graphite gaskets 5 on both sides under the unstable operation state of the strip (strip deviation, poor strip shape, strip jitter caused by a large amount of hydrogen input by the fan in the rapid cooling section). The normal operation state is: when high hydrogen is input in the rapid cooling section, the two groups of sealing rollers move towards the center line and work closely against the strip surface. When the strip is in an unstable state, the strip will first come into contact with the protection pipe 9 device, avoiding rubbing against the graphite gaskets 5 on both sides.

Claims

1. A structure for improving air tightness in a high hydrogen mode of a fast cooling section of a continuous annealing furnace, comprising a sealed roller chamber shell, rollers, and a sealed roller chamber shell lined with refractory bricks, characterized in that: The bottom of the roller is sealed and connected to the graphite sealing gasket, the bottom and both ends of the graphite sealing gasket are fixed by castables, a backing plate is arranged between the two ends of the castables and the refractory bricks lining the outer shell of the sealed roller chamber, a microporous insulation board is filled between the backing plate and the refractory bricks lining the outer shell of the sealed roller chamber, and the gaps in the upper end, side wall and bottom of the sealed roller chamber are filled with ceramic fibers.

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

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

4. The structure for improving air tightness in the high hydrogen mode of the rapid cooling section of a continuous annealing furnace according to claim 1, characterized in that: The cross-sectional dimensions of the square tube are (40-50) mm×(40-50) mm.

5. The structure for improving air 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 sealing gaskets are inclined downward in both directions, and the middle position of the two graphite sealing gaskets is the strip steel running channel. Protection tubes are also installed on both sides of the strip steel running channel, and bearings are arranged at both ends of the protection tubes.

6. A construction method for improving the airtightness of a structure in a high hydrogen mode of a rapid cooling section of a continuous annealing furnace according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: 1) Remove the 4 sealing rollers, drawers and pipes on each side of the sealing roller room, open the side door to form a passage; remove the lining insulation board and door reinforcement board around the sealing roller room; 2) After removing the pipes on the inner and outer walls at the bottom of the sealing roller room, weld steel plates everywhere to seal the holes; remove the plate strips, reinforcement ribs and threaded connection blocks behind the door; Then weld the drawer cover; 3) Re-weld the plate strips and reinforcement ribs at the new elevation point; and lay the lining and guard plate; 4) Installing a casting material adapted to the internal structure of the sealed roller chamber shell; 5) Install the graphite gasket and backing plate, and glue the square tube supporting the backing plate to the casting material on both sides at both ends of the sealing roller chamber; 6) Laying the lining: insert the microporous insulation board along the backing plate between the castable and the refractory bricks of the sealed roller chamber shell lining; fill all remaining gaps with ceramic fibers; 7) Reinstall the sealing roller and install protective tubes on both sides of the strip running channel.

7. The construction method of a structure for improving air tightness in a high hydrogen mode of a rapid cooling section of a continuous annealing furnace according to claim 6, characterized in that: The new elevation point is 1050-1100 mm from the top of the sealing roller chamber.

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