Crystallizer roughing slag treatment method

Abstract

The invention discloses a treatment method for crystallizer roughing slag. The treatment method specifically comprises the following steps that S1, blank drawing is stopped immediately after roughing slag in a crystallizer; s2, closing water at the upper parts of a foot roller and a bent section of the crystallizer; s3, the thickness of roughing slag in the crystallizer is measured, and corresponding treatment measures are taken according to the thickness of the slag; s4, pulling-straightening blank drawing is started, the blank drawing speed is controlled, and relevant water paths are opened in a matched mode; s5, the problem of steel slag generated after the tail blank goes out of the bent section is solved till the casting blank goes out of the fan-shaped section; according to the invention, more serious consequences caused by improper treatment after slag tapping of the crystallizer can be solved, and the purposes of promoting production stability, protecting equipment, reducing working intensity and the like are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking and continuous casting, in particular to a method for treating slag below a crystallizer. Background Art

[0002] In continuous casting, the tundish weighing equipment can experience inaccurate weighing due to factors such as the working environment and the impact of tundish handling. Operators often fail to monitor the liquid level and slag thickness in the tundish, leading to slag discharge into the mold at the end of the tundish production cycle. This mold slag discharge not only directly impacts ingot quality but also negatively impacts the smooth operation, efficiency, and cost of continuous casting. To effectively mitigate the impact of mold slag discharge on continuous casting stability, a practical and effective treatment method is needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a method for treating slag under the crystallizer to solve the more serious consequences caused by improper post-treatment of the slag under the crystallizer, so as to achieve the purposes of promoting production stability, protecting equipment, and reducing work intensity.

[0004] In order to solve the above technical problems, the technical solutions of the present invention are as follows: A method for treating slag from a crystallizer, comprising the following steps: S1: Stop casting immediately after the slag is discharged from the mold; S2: Turn off the water on the foot roller and the upper part of the bending section of the crystallizer; S3: Measure the thickness of the slag in the crystallizer and take corresponding treatment measures according to the slag thickness; S4: Start the straightening and casting process and control the casting speed, and open the relevant water channels; S5: Deal with the slag problem after the tail billet comes out of the bending section until the billet comes out of the fan-shaped section.

[0005] The present invention further defines the technical solution: Preferably, the method of measuring the thickness of the lower slag in the crystallizer in S3 is: inserting an oxygen burning tube into the crystallizer and then quickly pulling it out, and measuring the slag thickness through the slag layer attached to the oxygen burning tube.

[0006] Preferably, in S3, corresponding treatment measures are taken according to the slag thickness, specifically: if the slag thickness is ≥50mm, slag is removed by a slag removal tool, and when the cross-section is large, a shovel or a slag removal spoon is directly used to remove the slag. After the slag is removed, the slag thickness is measured again with an oxygen burning tube. After ensuring that the slag thickness is less than 50mm, the molten steel and liquid slag in the crystallizer are fully stirred with an oxygen burning tube, so that the liquid surface in the crystallizer and the crystallizer wall are fully in contact with each other to ensure that a shell larger than 100mm is formed, and then water is added to seal the top; if the slag thickness is ≤50mm, the liquid slag in the crystallizer is directly stirred with an oxygen burning tube to ensure that the liquid surface in the crystallizer and the crystallizer wall are fully in contact with each other to ensure that a shell larger than 100mm is formed, and then water is added to seal the top.

[0007] Preferably, the specific operations of starting the straightening and drawing and controlling the drawing speed in S4, and cooperating with opening the relevant water channels, are: starting the straightening and drawing, pulling out the crystallizer at a speed of 1.0 m / min, and the drawing cannot be stopped during this process; when the billet moves to the fourth roller of the bending section, the drawing speed is reduced to 0.4 m / min, and the foot roller of the crystallizer and the water on the upper part of the bending section are opened at the same time.

[0008] Preferably, the steps for dealing with the slag problem after the tail billet exits the bending section in said S5 include: immediately confirming whether there is an alarm on the fan-shaped segment straightening roller; if there is an alarm, the alarm should be confirmed quickly; if the upper straightening roller alarms and cannot be confirmed, the straightening roller should be lifted; the hot billet pressure of the horizontal segment straightening roller is converted into the ingot rod pressure to improve the billet drawing capacity of the fan-shaped segment; and notifying the electrical maintenance personnel to raise the roller gap of the straightening section by 30-50 mm.

[0009] Preferably, the step of processing the slag problem after the tail billet comes out of the bending section in said S5 also includes: if the billet still does not move after executing the operation of claim 5, the processing method is: change the production mode of the casting machine to the maintenance mode, reduce the secondary cooling water and atomizing air, and ensure a flow of 30-50L in each zone to cool the equipment; repeatedly perform the pulling-feeding operation on the crystallizer control panel or the jog handle to reduce the slag obstruction between the pulling and straightening rollers and the billet; raise the roller gaps of the remaining fan-shaped segments by 30-40mm, and the lifting sequence is from back to front; if the billet in the fan-shaped segment is completely solidified, press down the 1-3# segment pulling and straightening rollers, and repeatedly pull-feed until the billet comes out of the fan-shaped segment.

[0010] The beneficial effects of the present invention are as follows: the present invention avoids major accidents such as billet stagnation and steel leakage caused by improper handling through standardized operations, and significantly reduces the impact of human errors; by accurately controlling the slag layer thickness and the billet shell state, it avoids jamming caused by not removing thick slag or billet shell damage caused by excessive handling of thin slag; at the same time, the present invention forms a temperature control-shell protection-overflow prevention linkage mechanism by closing the crystallizer foot roller and the upper water of the bending section, reducing strong cooling, ensuring the billet temperature, slowing down the slag cooling speed, and coordinating with stirring to ensure that the billet shell is ≥100mm, thereby solving the problems of billet shell shrinkage and liquid core overflow caused by strong cooling in traditional operations. DETAILED DESCRIPTION

[0011] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific implementation methods. Example 1

[0012] This embodiment provides a method for treating slag in a crystallizer using a continuous casting production section of 270*1650mm, which specifically includes the following steps: S1: Stop casting immediately after the slag is discharged from the mold; S2: Turn off the water on the foot roll and the upper part of the bending section of the crystallizer to reduce the strong cooling of the billet, reduce the shrinkage of the billet shell, ensure the billet temperature, slow down the cooling rate of the slag and reduce the overflow of the liquid core of the billet due to shrinkage; S3: Insert the oxygen tube into the crystallizer and quickly pull it out to measure the slag thickness. Take corresponding treatment measures according to the slag thickness. Specifically, if the slag thickness is ≥50mm, use slag removal tools to remove the slag. If the cross-section is large, use a shovel or slag spoon to remove the slag directly. After removing the slag, use the oxygen tube to measure the slag thickness again. After ensuring that the slag thickness is less than 50mm, use the oxygen tube to stir the molten steel and liquid slag in the crystallizer to a large extent. Ensure that the liquid surface in the crystallizer is in full contact with the crystallizer wall. Ensure that the shell is larger than 100mm. Then, add water to seal the top. If the slag thickness is ≤50mm, directly use the oxygen tube to stir the liquid slag in the crystallizer to ensure that the liquid surface in the crystallizer is in full contact with the crystallizer wall. Ensure that the shell is larger than 100mm. Then, add water to seal the top. S4: Start the straightening and casting process and control the casting speed, and open the relevant water channels. Specifically, start the straightening and casting process and pull the billet out of the crystallizer at a speed of 1.0m / min. The casting process cannot be stopped during this process. When the billet reaches the fourth roller of the bending section, reduce the casting speed to 0.4m / min and open the water on the foot roller of the crystallizer and the upper part of the bending section. S5: Deal with the slag problem after the tail billet comes out of the bending section until the billet comes out of the fan-shaped section. Specifically: when the slag in the crystallizer comes out of the crystallizer with the tail billet, it will be quickly broken and fall between the billet and the fan-shaped section roller after forced cooling by the secondary cooling water, causing the billet to stop moving or to be stuck. First confirm whether the fan-shaped section straightening roller has an alarm. If there is an alarm, confirm the alarm quickly. If the upper straightening roller alarms and cannot be confirmed, lift the straightening roller; convert the hot billet pressure of the horizontal section straightening roller into the ingot rod pressure to improve the billet drawing capacity of the fan-shaped section; notify the electrical maintenance personnel The staff raises the roller gap of the straightening section by 30-50mm. If the billet still does not move, the casting machine production mode is switched to maintenance mode, and the secondary cooling water and atomizing air are reduced. A flow of 30-50L is guaranteed in each zone to cool the equipment. Repeated pulling-feeding operations are performed on the crystallizer control panel or the inching handle to reduce the slag obstruction between the straightening roller and the billet. At the same time, the roller gaps of the remaining fan-shaped segments are raised by 30-40mm, and the lifting sequence is from back to front. If the billet in the fan-shaped segment is completely solidified, the straightening rollers of segments 1-3 can be pressed down, and the pulling-feeding is repeated until the billet leaves the fan-shaped segment. Example 2

[0013] This embodiment provides a method for treating slag in a crystallizer based on a continuous casting production section of 270*2000mm, which specifically includes the following steps: S1: Stop casting immediately after the slag is discharged from the mold; S2: Turn off the water on the foot roll and the upper part of the bending section of the crystallizer to reduce the strong cooling of the billet, reduce the shrinkage of the billet shell, ensure the billet temperature, slow down the cooling rate of the slag and reduce the overflow of the liquid core of the billet due to shrinkage; S3: Insert the oxygen tube into the crystallizer and quickly pull it out to measure the slag thickness. Take corresponding treatment measures according to the slag thickness. Specifically, when the slag thickness is 30-50mm, use the oxygen tube to stir the liquid surface in the crystallizer on both narrow sides of the crystallizer to ensure that the liquid surface in the crystallizer is in full contact with the crystallizer wall to ensure that the shell is formed. After the shell is greater than 100mm, water is added to seal the top. S4: Start the straightening and casting process and control the casting speed, and open the relevant water channels. Specifically, start the straightening and casting process and pull the billet out of the crystallizer at a speed of 1.0m / min. The casting process cannot be stopped during this process. When the billet reaches the fourth roller of the bending section, reduce the casting speed to 0.4m / min and open the water on the foot roller of the crystallizer and the upper part of the bending section. S5: Deal with the slag problem after the tail billet comes out of the bending section until the billet comes out of the fan-shaped section. Specifically: when the slag in the crystallizer is forced to cool with the secondary cooling water after the tail billet comes out of the crystallizer, it will quickly break and fall between the billet and the fan-shaped section roller, causing the billet to stop moving or to be stuck. Confirm whether the fan-shaped section straightening roller has an alarm as soon as possible. If there is an alarm, confirm the alarm quickly. If the upper straightening roller alarms and cannot be confirmed, lift the straightening roller; convert the hot billet pressure of the horizontal section straightening roller into the ingot rod pressure to improve the billet drawing capacity of the fan-shaped section; notify the electrical maintenance The personnel raise the roller gap of the straightening section by 30-50mm. If the billet still does not move, the casting machine production mode is switched to maintenance mode, and the secondary cooling water and atomizing air are reduced. A flow rate of 30-50L of cooling equipment is guaranteed in each zone. The pulling-feeding operation is repeated on the crystallizer control panel or the inching handle to reduce the slag obstruction between the straightening roller and the billet. At the same time, the roller gap of the remaining fan-shaped segments is raised by 30-40mm, and the lifting sequence is from back to front. If the billet in the fan-shaped segment is completely solidified, the straightening rollers of segments 1-3 can be pressed down, and the pulling-feeding operation is repeated until the billet leaves the fan-shaped segment.

[0014] In addition to the above embodiments, the present invention may also have other implementation methods; any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A method for treating slag from a crystallizer, characterized in that: The specific steps include: S1: Stop casting immediately after the slag is discharged from the mold; S2: Turn off the water on the foot roller and the upper part of the bending section of the crystallizer; S3: Measure the thickness of the slag in the crystallizer and take corresponding treatment measures according to the slag thickness; S4: Start the straightening and casting process and control the casting speed, and open the relevant water channels; S5: Deal with the slag problem after the tail billet comes out of the bending section until the billet comes out of the fan-shaped section.

2. The method for treating mold slag according to claim 1, wherein: The method for measuring the thickness of the lower slag in the crystallizer in S3 is: inserting an oxygen burning tube into the crystallizer and then quickly pulling it out, and measuring the slag thickness through the slag layer attached to the oxygen burning tube.

3. The method for treating mold slag according to claim 1, wherein: In S3, corresponding treatment measures are taken according to the slag thickness, specifically: if the slag thickness is ≥50 mm, slag is removed by using a slag removal tool. When the cross-section is large, a shovel or a slag removal spoon is directly used to remove the slag. After removing the slag, the slag thickness is measured again with an oxygen burning tube. After ensuring that the slag thickness is less than 50 mm, the molten steel and liquid slag in the crystallizer are fully stirred with the oxygen burning tube to ensure that the liquid surface in the crystallizer and the crystallizer wall are in full contact with each other to ensure that a shell larger than 100 mm is formed, and then water is added to seal the top; if the slag thickness is ≤50 mm, the molten steel and liquid slag in the crystallizer are directly stirred with the oxygen burning tube to ensure that the liquid surface in the crystallizer and the crystallizer wall are in full contact with each other to ensure that a shell larger than 100 mm is formed, and then water is added to seal the top.

4. The method for treating mold slag according to claim 1, wherein: The specific operations of starting the straightening and drawing process and controlling the drawing speed in S4, in conjunction with opening the relevant water channels, are as follows: starting the straightening and drawing process, pulling the billet out of the crystallizer at a speed of 1.0 m / min, and the billet drawing cannot be stopped during this process; when the billet moves to the fourth roller of the bending section, the billet drawing speed is reduced to 0.4 m / min, and the foot roller of the crystallizer and the water on the upper part of the bending section are opened at the same time.

5. The method for treating mold slag according to claim 1, wherein: The steps for dealing with the slag problem after the tail billet exits the bending section in S5 include: immediately confirming whether the fan-shaped segment straightening roller has an alarm; if an alarm is issued, the alarm should be confirmed quickly; if the upper straightening roller alarms and cannot be confirmed, the straightening roller should be raised; the hot billet pressure of the horizontal segment straightening roller is converted into the ingot rod pressure to improve the billet drawing capacity of the fan-shaped segment; and notifying the electrical maintenance personnel to raise the roller gap of the straightening section by 30-50 mm.

6. The method for treating mold slag according to claim 5, characterized in that: The step of processing the slag problem after the tail billet exits the bending section in the said S5 also includes: if the billet still does not move after executing the operation of claim 5, the processing method is: switching the casting machine production mode to maintenance mode, reducing the secondary cooling water and atomizing air, and ensuring a flow of 30-50L in each zone to cool the equipment; repeatedly performing the pulling-feeding operation on the crystallizer control panel or the jog handle to reduce the slag obstruction between the pulling and straightening rollers and the billet; raising the roller gaps of the remaining fan-shaped segments by 30-40mm, and the lifting sequence is from back to front; if the billet in the fan-shaped segment is completely solidified, pressing down the 1-3# segment pulling and straightening rollers, and repeatedly pulling-feeding until the billet exits the fan-shaped segment.