Method for removing indentation on the surface of the top roller of a vertical bright annealing furnace on line

Abstract

A method for removing the indentation on the surface of the furnace top roller of a vertical bright annealing furnace online, comprising the following steps: locking the roller system of the furnace top roller according to the period of the surface defect points of the strip steel and the low-speed operation of the unit; using the function of the furnace top deviation correction roller, and using the shear force and friction force generated by the transverse movement of the strip steel and the roller surface to clean the indentation on the roller surface during the deviation correction process; and for the indentation on the furnace top steering roller, the rotation friction of the roller is used to eliminate the indentation on the basis of combining the action of the deviation correction roller. The present application can effectively remove the indentation defects on the surface of the strip steel, the operation time is shortened from the traditional 18-22 hour processing process to 20-30 minutes, the removal effect is good, the time is short, the time of abnormal shutdown is greatly saved, the consumption of energy media such as fuel gas, hydrogen and nitrogen is reduced, the cost is reduced, and the product quality and the stable production of the unit are ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cold-rolled stainless steel production, and relates to a method for removing pressure indentation on the surface of a top roller of a vertical bright annealing furnace on line. BACKGROUND

[0002] A continuous annealing production line is characterized by a large number of roller systems. In the production process, the surface of each roller system is pressed into (or adhered to) by foreign matter, thereby causing pressure indentation defects of the strip steel and affecting the surface quality of the product.

[0003] For the problem of roller surface pressure indentation, most of the roller systems of the annealing production line can be treated on line, or treated or replaced with less downtime, which has little effect on production organization. However, for a closed facility, it is difficult to treat the above-mentioned roller surface pressure indentation defects.

[0004] A vertical bright annealing furnace is a key equipment of a bright annealing production line, which is a closed furnace type. The bright furnace is filled with hydrogen protective gas, and the furnace is not easily opened, because opening the furnace will cause damage to the dew point atmosphere in the furnace, and it takes a long time to recover. The vertical furnace has a narrow strip steel passage, and when the strip steel has poor flatness and the thick material groove is too large, it is easy to cause scratches with the passage steel structure, resulting in metal chip peeling, and the inclusions of the strip steel itself peeling after annealing, and finally adhering to the roller surface in the furnace. Finally, the pressure indentation on the roller surface causes periodic point indentation defects on the surface of the strip steel.

[0005] The structure of the vertical bright annealing furnace is shown in Figure 1 According to the running direction of the strip steel 1, it passes through the inlet sealing roller 2, the heating zone (muffle) 3, the cooling zone 4 (containing one group of graphite stabilizing rollers 22), the top roller zone 5 (containing two rubber rollers 100 and 200), the return passage 6 (containing two groups of stabilizing rollers 33, 44), and the outlet sealing roller 7, and finally the annealed strip steel leaves the furnace. Among all the roller systems in contact with the strip steel in the bright furnace, the sealing rollers 2 and 7 have part of the roller surface outside the furnace, and the stabilizing rollers 22, 33 and 44 can adjust the position not to contact the strip steel 1, so that the pressure indentation defects can be treated on line or stopped, without causing continuous defects on the strip steel. However, when the two rubber rollers 100 and 200 in the top roller zone 5 produce pressure indentation, they cannot be treated on line or stopped off line. At present, the conventional treatment method is to stop the machine set, cool down the furnace, replace hydrogen with nitrogen, open the furnace for pressure indentation treatment when the temperature in the furnace is appropriate, and finally start firing the furnace, nitrogen purging, hydrogen replacement, and dew point adjustment to start production. The whole treatment cycle is long, and a lot of manpower and resources are consumed.

[0006] According to the investigation, the existing Chinese patent with the publication number CN111926169B "Method for online processing of indentation defects in a bright annealing furnace" includes: 1) a scraper opening is formed at one end of the bright annealing furnace inlet corresponding to the entering steel strip; 2) after the entering steel strip enters the furnace area and the scraper opening is close to the rubber roller, the running speed of the entering steel strip is reduced to below 6 mpm; 3) the position of the scraper opening is accurately positioned; 4) the production line is stopped, the rubber roller is reversely rotated, and the iron filings and other foreign matters attached or adhered to the two side parts of the rubber roller are removed through the scraper opening; 5) the cleaning of the rubber roller is completed, and the production line is restarted. The patent provides a processing method for indentation defects in a bright annealing furnace, which has good effect, but also has certain limitations, and is not suitable for Figure 1 The structure of the top roller of the vertical bright annealing furnace. Since the indentation generally occurs on the roller surface away from the edge of the steel strip, the method of opening a scraper opening through the edge of the steel strip can remove the indentation of the roller surface, but indentation points sometimes occur in the middle of the steel strip, and the above method cannot handle it; secondly, the roller is rotated to remove the indentation of the roller surface, but if the roller is a driven roller, it cannot be rotated, and if a pipe wrench is used to rotate, the end sealing side cover of the correction roller must be opened, and the hydrogen in the furnace must be replaced before this premise, which destroys the atmosphere in the furnace. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a method for online removal of indentation of the top roller surface of a vertical bright annealing furnace, which can effectively remove the indentation defects on the surface of the steel strip, has good removal effect, short time, and ensures product quality and stable production of the unit.

[0008] The technical solution adopted by the present application to solve the above technical problem is: a method for online removal of indentation of the top roller surface of a vertical bright annealing furnace, characterized by comprising the following steps:

[0009] 1) First, the process speed of the production line is reduced to 10-20 mpm according to the specific situation;

[0010] 2) Determine the position of the indentation defect on the steel strip: the operating side (WS) or the driving side (DS) or the position in the middle of the width direction of the steel strip, and lock the top roller system under low speed operation of the unit;

[0011] 3) If it is determined that the top correction roller is indented, switch the EMG control of the top correction roller near the machine to "MAN" mode, and reduce the process speed to 5-10 mpm;

[0012] 4) for the press-in point located at the operation side (WS) or the drive side (DS), the action of operating the furnace top correction roller on the EMG control box makes the strip steel run away from the direction of the press-in point, so that the press-in point on the roller surface appears outside the strip steel coverage area, and then the EMG control is switched to the "AUTO" mode, the strip steel automatically returns to the original position from the deviated position, and during the returning process, the strip steel has a relative transverse movement while continuing to run forward, and the edge of the strip steel has a transverse tangential force along the roller surface to clean the press-in point on the roller surface;

[0013] 5) for the press-in point located in the middle of the strip steel, which cannot be removed from the strip steel coverage area by correction limited to the width of the strip steel, the above method can also be adopted to reciprocate the strip steel left and right to loosen and drop the press-in point on the roller surface through the transverse friction force between the strip steel and the roller surface;

[0014] 6) the EMG is switched to the "MAN" mode again, and the strip steel is deviated from the roller surface to confirm whether the press-in point on the roller surface is completely cleaned, if the press-in point is still present, steps 4) or 5) are repeated until the roller surface foreign matter is completely cleaned;

[0015] 7) if it is determined that the furnace top deflection roller is pressed in, on the basis of the action of the furnace top correction roller, the rotation friction of the roller is supplemented to eliminate the press-in on the roller surface.

[0016] Further, the wrap angle between the furnace top correction roller and the strip steel is 1 / 8 ± 0.02 roller surface, and the wrap angle between the furnace top deflection roller and the strip steel is 3 / 8 ± 0.05 roller surface.

[0017] Further, in step 4), when the furnace top correction roller is operated in the "MAN" mode, the control button needs to be operated intermittently, and the correction is stopped when the distance from the edge of the strip steel is 100 mm ± 10 mm, or the press-in point is separated from the edge of the strip steel by 100-150 mm.

[0018] Further, in step 4), when the furnace top correction roller is operated in the "MAN" mode, a conspicuous reference object needs to be found at the edge of the roller surface, and the reference object is in front of the press-in point along the deflection of the correction roller, and the start of the correction action of the roller is determined by the reference object.

[0019] Further, the specific process for removing the press-in point of the furnace top deflection roller in step 7) is as follows:

[0020] a. The press-in point on the furnace top deflection roller can also be removed by the correction action of the furnace top correction roller;

[0021] b. When the pressing point is close to the disengagement from the strip contact, the production line needs to be stopped, the furnace tension is unloaded, and the strip is sent back to the furnace through the outlet sealing roller to keep the strip in the furnace in a relaxed state. Finally, the top roller is operated to rotate back and forth within a range of 60±5° around the pressing point, and the relative friction between the roller and the strip is used to loosen and peel off the pressing point to achieve the cleaning purpose.

[0022] Preferably, the strip specifications are 0.5-1.5 mm thick and 800-1250 mm wide. If the strip is too thin, it will wrinkle due to lateral stress during correction. If the strip is too wide, there is a risk of the strip disengaging from the roller surface during correction.

[0023] Finally, the method requires the cooperation of two operators. Operator A operates the EMG control box at the machine, and operator B observes the pressing point and the action of the correction roller and the strip at the top roller box sight hole. Operator B directs operator A to operate the correction roller.

[0024] Compared with the prior art, the present application has the advantages that the correction method of the top roller correction roller is used, i.e., the pressing point position of the strip deviating from the roller surface is achieved by the action of the correction roller, and then the strip automatically returns to the initial position. During the return process, the strip has a tangential force on the pressing point of the roller surface, so that the pressing point is separated from the roller surface and falls off, thereby achieving the cleaning of the pressing point on the roller surface. The present application can effectively remove the pressing defects on the surface of the strip. The processing time is shortened from 18-22 hours to 20-30 minutes, the cleaning effect is good, the time is short, the time of abnormal shutdown is greatly saved, the consumption of energy media such as fuel gas, hydrogen, and nitrogen is reduced, the cost is reduced, the product quality and the production stability of the unit are ensured, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a vertical bright annealing furnace provided by the present application;

[0026] Figure 2 is a roller system actual view of the top roller box area of the vertical bright annealing furnace provided by the present application;

[0027] Figure 3 is a correction action schematic diagram of the top correction roller provided by the present application;

[0028] Figure 4 is a positioning schematic diagram of the top steering roller provided by the present application. DETAILED DESCRIPTION

[0029] The present application is further described in detail below in combination with the embodiments of the drawings.

[0030] As shown in Figures 1-4 , a method for cleaning the pressing point on the top roller surface of a vertical bright annealing furnace on line includes the following steps:

[0031] 1) First, reduce the process speed of the production line to 10-20mpm based on the specific situation;

[0032] 2) Determine the location of the indentation on the strip 1: on the operating side (WS) or the drive side (DS) or in the middle of the width of the strip 1, and lock the top roller system when the unit is running at low speed;

[0033] 3) If it is determined that the furnace top correcting roller (driven roller) 100 is pressed in, switch the EMG control of the furnace top correcting roller 100 next to the machine to "MAN" mode, and reduce the process speed to 5-10 mpm;

[0034] 4) For the pressing point on the operating side (WS) or the transmission side (DS), operate the furnace top correction roller 100 on the EMG control box to make the strip 1 deviate from the direction of the pressing point and make the pressing point on the roller surface appear outside the coverage area of ​​the strip 1 ( Figure 3 ), then switch the EMG control to "AUTO" mode, and the strip automatically returns to its original position from the deviated position. During the return process, the strip continues to move forward while having a relative lateral movement with the roller surface. The edge of the strip 1 has a lateral tangential force along the roller surface, which clears the pressure point on the roller surface;

[0035] Step 4) When the furnace top deflection correction roller 100 is operated in "MAN" mode, the control button needs to be operated in a jog manner, and the deflection correction is stopped when the distance from the edge of the strip 1 is 100 mm ± 10 mm, or the deflection correction is stopped when the pressing point is 100-150 mm away from the edge of the strip 1;

[0036] Step 4) When operating the furnace top correction roller 100 in "MAN" mode, it is necessary to find a conspicuous reference object 9 away from the edge of the roller surface. Along the direction of the furnace top correction roller 100, the reference object 9 is in front of the pressing point 8. The start of the roller correction action is determined by the reference object 9.

[0037] 5) For the pressing point located in the middle of the strip 1, which cannot be separated from the strip coverage area by correction due to the width of the strip 1, the above method can also be adopted to correct the strip back and forth left and right, and through the lateral friction between the strip and the roller surface, the pressing point on the roller surface can be loosened and fall off.

[0038] 6) Switch the EMG to "MAN" mode again and make the strip 1 deviate from the roller surface to confirm whether the pressure point on the roller surface is completely removed. If the pressure point is still there, repeat step 4) or step 5) until the foreign matter on the roller surface is cleared;

[0039] 7) If it is determined that the furnace top steering roller (active roller) 200 is pressing in, based on the action of the furnace top correcting roller 100, the rotational friction of the roller is used to eliminate the roller surface pressing in.

[0040] The specific process for removing the indentation point on the top deflection roller 200 is as follows:

[0041] a. The indentation point 2 on the top deflection roller 200 can also be removed by the correction action of the top correction roller 100.

[0042] b. When the indentation point 2 is about to run away from the contact with the strip 1, Figure 4 the production line needs to be stopped, the tension of the furnace is released, and the strip 1 is sent back into the furnace by the outlet sealing roller to keep the strip in the furnace in a relaxed and hanging state. Finally, the top deflection roller 200 is operated to rotate back and forth within a range of 60±5° centered on the indentation point 2, and the relative friction between the roller and the strip 1 is used to loosen and peel off the indentation point 2, achieving the purpose of removal.

[0043] The specifications of the strip 1 are 0.5-1.5mm thick and 800-1250mm wide.

[0044] The wrap angle between the top correction roller 100 and the strip 1 is 1 / 8±0.02 roller surface, and the wrap angle between the top deflection roller 200 and the strip 1 is 3 / 8±0.05 roller surface.

[0045] Example 1

[0046] The machine set is producing strip with specifications of 0.6mm×1030mm, and it is confirmed that there is an indentation defect on the lower surface of the strip 1 at a distance of 50mm from the WS side, with a period P=2640mm. It is confirmed that the indentation is caused by a Φ840mm roller in the furnace.

[0047] Further confirmation is made through the peephole above the top roller box that the indentation is caused by the top correction roller 100, and the process speed of the strip 1 is immediately reduced to 8m / min. Personnel A controls the EMG, and personnel B observes the state of the strip 1 in real time through the peephole.

[0048] The EMG control box is switched to "MAN" mode, and the strip 1 is deviated to the DS side by operating the jog control button. When the indentation point 8 is seen, the button operation is stopped, and the strip 1 runs at a low speed in the deviated state. At the same time, according to the position of the indentation point 8, a more prominent reference object 9 (such as marks on the roller surface) is found about 50-100mm in front of the indentation point 8 (in the direction of roller operation) and outside the coverage area of the strip 1.

[0049] After the reference object 9 is determined, with the continuous operation of the top correction roller 100, when the reference object is seen again, the EMG is switched to "AUTO" mode, and the top correction roller 100 starts to move to make the strip 1 have a relative movement with the top correction roller 100 from the original deviated state, until the strip 1 and the top correction roller 100 reach a stable state.

[0050] During the relative movement between the strip 1 and the furnace top deviation correcting roller 100, the indentation point 8 on the roller surface has a tangential movement in the 1 / 8 roller surface wrap angle from the strip 1 to the roller surface before the strip 1 reaches the initial position. Figure 3 The middle 11 is the strip in the normal position during operation, the 12 is the strip position after correction, and the arrow is the forward direction of the strip.

[0051] After the strip 1 is stabilized, the EMG is switched to the "MAN" mode again, the strip 1 is deviated to the DS side, it is confirmed that the indentation point 8 on the original roller surface has been completely eliminated, finally the EMG is switched to the "AUTO" mode, and the unit returns to normal production.

[0052] The present application is implemented, and the original treatment process of 18-22 hours (in which the furnace cooling and heating each need about 8 hours on average) is shortened to 20-30 minutes. The present application effectively removes the indentation defects on the surface of the strip while greatly shortening the time, improving the production efficiency, and reducing the consumption of energy media such as fuel gas, hydrogen, nitrogen and the like, thereby saving the cost.

[0053] The above description is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for online removal of indentation on the top roll face of a vertical bright annealing furnace, characterized in that The method comprises the following steps: 1) firstly, reduce the production line speed to 10-20 mpm according to the specific situation; 2) determine the position of the indentation on the strip: the operation side or the transmission side or the middle of the strip width, and lock the furnace top roll system at low speed of the unit; 3) if the indentation is determined to be on the furnace top correction roll, switch the EMG control of the furnace top correction roll near the machine to "MAN" mode, and reduce the production speed to 5-10 mpm; 4) for the indentation on the operation side or the transmission side, operate the action of the furnace top correction roll on the EMG control box to make the strip run in the direction away from the indentation, so that the indentation on the roll surface is out of the coverage area of the strip, then switch the EMG control to "AUTO" mode, the strip automatically returns to the original position from the deviation position, and the strip continues to run forward while having a relative transverse motion with the roll surface, the lateral tangential force of the edge of the strip along the roll surface removes the indentation on the roll surface; 5) for the indentation on the middle of the strip, which cannot be removed from the coverage area of the strip by correction due to the width of the strip, the above method can also be used, that is, the strip is reciprocated left and right to loosen and fall off the indentation on the roll surface by the transverse friction between the strip and the roll surface; 6) switch the EMG to "MAN" mode again, and make the strip deviate from the roll surface to confirm whether the indentation on the roll surface is completely removed, if the indentation is still there, repeat steps 4) or 5) until the indentation on the roll surface is completely removed; 7) if the indentation is determined to be on the furnace top turning roll, based on the action of the furnace top correction roll, the rotation friction of the roll is used to remove the indentation on the roll surface; the specific process of removing the indentation on the furnace top turning roll in step 7) is as follows: a. the indentation on the furnace top turning roll can also be removed by the correction action of the furnace top correction roll; b. when the indentation is about to run out of the contact with the strip, the production line needs to be stopped, the tension of the furnace is released, and the strip is sent back a little through the outlet sealing roll to keep the strip in the furnace in a relaxed and hanging state, finally, the furnace top turning roll is operated to reciprocate within 60±5° range centered on the indentation, and the relative friction between the roll and the strip is used to loosen and fall off the indentation to achieve the purpose of removing the indentation.

2. The method of claim 1, wherein: The wrap angle between the furnace top correction roll and the strip is 1 / 8±0.02 roll surface, and the wrap angle between the furnace top turning roll and the strip is 3 / 8±0.05 roll surface.

3. The method of claim 1, wherein: When the furnace top correction roll is operated in "MAN" mode in step 4), the control button needs to be operated intermittently, and the correction is stopped when the strip edge is 100mm±10mm away, or the correction is stopped when the indentation is 100-150mm away from the edge of the strip.

4. The method of claim 1, wherein: When the furnace top correction roll is operated in "MAN" mode in step 4), a conspicuous reference object needs to be found at the edge of the roll surface, and the reference object is in front of the indentation along the turning direction of the correction roll, and the start of the correction action of the roll is determined by the reference object.

5. The method according to any one of claims 1 to 4, characterized in that: The specifications of the strip are 0.5-1.5mm thick and 800-1250mm wide.

6. The method of any of claims 1 to 4, wherein: The method needs two operators to operate, operator A operates the EMG control box near the machine, and operator B observes the pressing point and the action of the correcting roller and the strip steel at the peephole of the top roller box, and operator B commands operator A to operate the action of the correcting roller.

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