Method for emergency disposal of continuous cutting of large-section casting blank
By using a combination of a special firing torch and high-pressure, high-purity oxygen, the problem of the billet being unable to be cut during online cutting was solved, enabling rapid emergency response and avoiding production interruptions.
Patent Information
- Application Number
- CN202511153763.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-14
AI Technical Summary
During continuous casting, the billet cannot be cut normally due to reasons such as slag overflow of the cutting torch, abnormal cutting gas source, or communication failure of the cutting trolley, resulting in unplanned shutdowns and production interruptions.
By employing a combination of a special firing torch and high-pressure, high-purity oxygen, the online cutting of the cast billet is achieved through precise operations in the ignition, grooving, and cutting stages.
The rapid cutting of the billet avoids unplanned downtime, reduces production losses, and ensures production continuity.
Smart Images
Figure CN120940593A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of continuous casting, specifically to a method for handling large-section cast billets that cannot be cut in an emergency. Background Technology
[0002] The continuous casting slab production process involves continuously casting molten steel into slabs of fixed specifications. Its core lies in efficiently and continuously transforming the molten steel into a solid slab suitable for rolling. Molten steel is poured from the ladle into the tundish, and then from the tundish into the crystallizer through a submerged entry nozzle. In the crystallizer, forced cooling rapidly solidifies the surface of the molten steel, forming a thin shell. The initially solidified slab then enters the secondary cooling zone, where it is further cooled by segmented spraying, gradually thickening the shell until it completely solidifies. The completely solidified slab is then flame-cut into the required lengths for rolling.
[0003] During the online cutting process of cast billets, issues such as slag spillage by the cutting torch, abnormal cutting gas supply, or communication failure of the cutting carriage may prevent the billet from being cut. If this situation is not addressed promptly, a billet ejection accident may occur, leading to unplanned downtime of the casting machine and severely impacting production.
[0004] In summary, the existing technology has the following problems: during the online cutting of the billet, the billet may fail to be cut normally due to unexpected reasons such as slag spillage of the cutting torch, abnormal cutting gas source, or communication failure of the cutting carriage. Summary of the Invention
[0005] This invention provides an emergency method for handling large-section cast billets that cannot be cut, in order to solve the problem of cast billets being unable to be cut normally due to unexpected reasons during online cutting.
[0006] Therefore, the present invention proposes an emergency method for handling large-section cast billets that cannot be cut, characterized in that the emergency method for handling large-section cast billets that cannot be cut includes the following steps:
[0007] Step S1: Ignition of the billet: First, use a propane torch to ignite the billet at the surface edge.
[0008] Step S2: Grooving stage: After the billet is ignited normally, replace the propane cutting torch with a special torch for burning billets. Use the propane cutting torch to cut the high-temperature melt generated during the cutting of the billet, ignite the special torch for burning billets, connect the special torch for burning billets to the high-pressure oxygen source, and cut the surface of the billet back and forth 1-2 times to form a slit on the surface of the billet.
[0009] Step S3: Cutting stage: After a slit is formed on the surface of the billet, cut back and forth 6-8 times to cut the billet online without stopping the machine;
[0010] Furthermore, the propane cutting torch is ignited at point A;
[0011] In this process, a propane cutting torch is used to cut the edge of the billet, while a special torch for firing billets with the oxygen flow rate adjusted is placed at the cut edge of the billet.
[0012] During the initial ignition, point A on the surface edge of the billet is the starting position, and the billet is ignited at point A. In the grooving stage: the angle between the replaceable oxygen tube of the firing torch and the billet is 15-20°. Using the firing torch, the torch is moved at a constant speed from point A to point B on the billet, and then back from point B to point A. This back-and-forth cutting of the billet surface is repeated 1-2 times, forming a slit on the billet surface. The line connecting points A and B represents the width direction of the billet, and points A and B are the points on the two lengthwise sides of the upper surface of the billet, respectively. The distance between points A and B is equal to the width of the billet.
[0013] Cutting stage: After a kerf is formed on the surface of the billet, at the starting position A, adjust the angle between the sintering torch and the billet surface to 15-20°, and then move it at a constant speed from point A to point B. When the propane cutting torch reaches point B, adjust the angle between the sintering torch and the billet to 30-45°, and then move it at a constant speed from point B to point A. Repeat this back-and-forth cutting 6-8 times. Each time from point A to point B, the angle between the sintering torch and the billet surface is 15-20°. When returning, the angle between the sintering torch and the billet surface is 30-45° from point B to point A, until the billet is cut off online.
[0014] This invention, after initially using a propane cutting torch for ignition of the billet, employs a special billet-specific torch, utilizing high-pressure, high-purity oxygen to repeatedly purge the ignited billet, achieving large-section billet cutting. Compared to using only a propane cutting torch, this method, by purging the ignited billet with high-pressure, high-purity oxygen, offers a much faster cutting speed, essentially equivalent to the speed of automatic online billet cutting. Therefore, it can be used as an emergency measure when the billet cannot be cut normally due to unforeseen circumstances, without requiring machine downtime. This emergency handling does not affect subsequent production, reducing downtime losses. Attached Figure Description
[0015] Figure 1 This is a schematic diagram illustrating the structural principle of the special gun for firing blanks according to the present invention;
[0016] Figure 2 To employ the method of this invention, the angle between the sintering torch and the billet is determined during the grooving stage (when the torch is being fed in).
[0017] Figure 3 To employ the method of this invention, the angle between the sintering torch and the cast billet is determined during the cutting stage (when the torch is returned).
[0018] Figure 4 This is a schematic diagram showing the direction of movement of the billet. Detailed Implementation
[0019] To provide a clearer understanding of the technical features, objectives, and effects of this invention, the invention is now described.
[0020] In continuous casting, the billet is cut to a planned length and then transported to a designated location via a crane on a roller conveyor. When the billet cannot be cut, it cannot be transported off the roller conveyor, causing it to become clogged and resulting in a billet overflow accident, leading to production interruption. The usual procedure is to stop production, manually cut the billet with an acetylene flame, and resume production after the billet is cleared from the roller conveyor. However, this results in unplanned downtime of the casting machine, severely impacting smooth production operations.
[0021] This invention employs a firing process, using specialized firing tools to manually cut the cast billet online without requiring machine downtime.
[0022] 1. Tools required for firing the clay blanks.
[0023] (1) Propane cutting torch, used for igniting the blanks.
[0024] A special firing torch (including a replaceable oxygen tube) is used to fire cast billets (cross-sectional dimensions, for example: width: 900-2000mm, thickness: 150-300mm). Figure 1 As shown, the special gun for firing billets includes: an oxygen hose connected to a high-pressure oxygen source, a handheld tube connected to the oxygen hose, and a replaceable oxygen tube detachably connected to the handheld tube. The oxygen hose is equipped with an adjustment valve. The handheld tube is the part held by the operator. The replaceable oxygen tube is detachably connected to the handheld tube, for example, by a threaded connection or a snap-fit, for quick replacement. The dimensions of the handheld tube are: diameter 3-4cm and length 60-70cm; the diameter of the replaceable oxygen tube is 1.8-2cm and the length is 250-300cm. The replaceable oxygen tube comes into contact with the billet and is easily melted and damaged during the cutting process. When the replaceable oxygen tube of the special gun for firing billets melts or is damaged during the cutting of the billet, a new replaceable oxygen tube should be installed.
[0025] (2) High-pressure oxygen source, used to provide high-pressure, high-purity oxygen during the firing process. The pressure of the high-pressure oxygen source is ≥1.0MPa and the oxygen purity is ≥98%, for example, 1.0MPa and 99% oxygen purity. The high-pressure oxygen source comes from the oxygen pipeline provided by the oxygen plant for smelting and continuous casting.
[0026] The specific steps of firing the blanks are as follows:
[0027] 1) Adjust the oxygen flow rate of the firing torch, such as... Figure 2 and Figure 3 as well as Figure 4As shown, adjust the firing torch to a 15-20° angle with the surface of the billet, and then place the outlet end of the replaceable oxygen tube at the edge of the billet, i.e., point A.
[0028] (2) Then use a propane cutting torch to ignite the edge of the billet.
[0029] (3) Grooving stage: After the billet is ignited normally, maintain an angle of 15-20° between the billets. Use a special torch to move the billet from point A to point B at a constant speed, and then return from point B to point A. Cut the billet surface back and forth 1-2 times in this way. A slit will be formed on the billet surface. This slit is conducive to the removal of molten slag and the cutting of the billet.
[0030] (4) Cutting Stage: Starting from point A, adjust the angle between the sintering torch and the billet surface to 15-20° (this angle is small, making it easier to clean the cut on the billet). Then, move the torch from point A to point B at a constant speed. After the torch reaches point B, adjust the angle between the torch and the billet to 30-45° (this angle is large, making it easier to deepen the cut on the billet and facilitate rapid cutting). Then, move the torch from point B to point A at a constant speed. Repeat this back-and-forth cutting 6-8 times until the billet is successfully cut. Each time from point A to point B, the angle is 15-20° (grooving + cutting torch entry); when returning, the angle from point B to point A is 30-45° (cutting torch return).
[0031] The normal production speed of the billet is 1.3-1.7 m / min. If the billet cannot be cut, the casting speed will be reduced to 0.9 m / min during the emergency handling period.
[0032] In this embodiment of the invention, a method and apparatus for emergency handling of large-section cast slabs that cannot be cut are provided. The following is an application example at the No. 6 slab casting machine of Liuzhou Iron and Steel Converter Plant:
[0033] 1. Emergency handling process for a 220*1800mm cross-section cast billet that cannot be cut.
[0034] (1) When the operator below the platform encounters a billet that cannot be cut, immediately notify the machine operator and explain the reason why it cannot be cut.
[0035] (2) When the machine operator receives information that the billet cannot be cut, he immediately organizes personnel to carry out emergency response, namely billet firing operation;
[0036] The reasons why the billet could not be cut were investigated through relevant personnel.
[0037] (3) Adjust the oxygen flow rate of the special gun for firing billets (adjust to 80-100L / min, for example, 95L / min), and then place the outlet end of the replaceable oxygen tube at the edge of the billet that has not been cut off.
[0038] (4) Use a propane cutting torch to ignite the edge of the uncut point of the billet.
[0039] (5) After the ignition is normal, use a special gun for firing billets to blow back and forth on the surface of the billet to cut the billet.
[0040] (6) The entire firing operation takes 4 minutes and 56 seconds, which is equivalent to the 5 minutes of automatic cutting. Therefore, the present invention can perform online manual cutting without stopping the machine, and can realize emergency handling of large cross-section casting billets.
[0041] 2. Emergency handling process for a 220*1255mm cross-section cast billet that cannot be cut.
[0042] (1) When the operator below the platform encounters a billet that cannot be cut, immediately notify the machine operator and explain the reason why it cannot be cut.
[0043] (2) When the machine operator receives information that the billet cannot be cut, he immediately organizes personnel to carry out emergency response, namely billet firing operation;
[0044] The reasons why the billet could not be cut were investigated through relevant personnel.
[0045] (3) Adjust the oxygen flow rate of the special gun for firing billets (adjust to 80-100L / min, for example, 90L / min), and then place the outlet end of the replaceable oxygen tube at the edge of the billet that has not been cut off.
[0046] (4) Use a propane cutting torch to ignite the edge of the uncut point of the billet.
[0047] (5) After the ignition is normal, use a special gun for firing billets to blow back and forth on the surface of the billet to cut the billet.
[0048] (6) The rectification and firing operation takes 3 minutes and 6 seconds, which is equivalent to the 3 minutes of automatic cutting. No machine stop is required, and large-section casting billets can be handled in an emergency.
[0049] 3. Comparative example (conventional emergency handling process for 220*1800mm cross-section cast billet that cannot be cut): using a conventional cutting torch (propane cutting torch).
[0050] (1) When the operator below the platform encounters a billet that cannot be cut, immediately notify the machine operator and explain the reason why it cannot be cut.
[0051] (2) When the captain receives information that the billet cannot be cut, he immediately organizes personnel to carry out emergency response, namely, to cut the billet with a handheld propane cutter and to investigate the reason why the billet cannot be cut through the relevant positions.
[0052] (3) Adjust the flame of the handheld propane cutter and then place the handheld cutter at the edge of the billet.
[0053] (4) Use a handheld propane cutter to ignite the edge of the billet.
[0054] (5) After normal ignition, move the propane cutting torch at a constant speed to cut the billet.
[0055] (6) The entire cutting process used only a propane cutter, which took 9 minutes and 58 seconds. Compared with the special firing method, the time was about doubled. Due to the long cutting time, the accident was not handled properly, which ultimately led to the billet being ejected and production was forced to stop.
[0056] 3. Comparison of the two solutions above: By using the large-section billet cutting method of this invention, the cutting time is short, and the cutting can be completed without stopping the machine. This saves time for troubleshooting the cause of continuous billet cutting and avoids accidents that interrupt the casting machine's production. In contrast, conventional acetylene-oxygen cutting or other conventional cutting methods take a long time, which affects the continuous production of billets and requires machine shutdown.
[0057] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. The various components of the present invention can be combined with each other without conflict. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.
Claims
1. A method for emergency handling of large-section cast billets that cannot be cut, characterized in that, The emergency treatment method for large-section cast billets that cannot be cut includes the following steps: Step S1: Ignition of the billet: First, use a propane torch to ignite the billet at the surface edge. Step S2: Grooving stage: After the billet is ignited normally, replace the propane cutting torch with a special billet firing torch. Use the high-temperature melt generated during billet cutting to ignite the special billet firing torch. Connect the special billet firing torch to the high-pressure oxygen source and cut the billet surface back and forth 1-2 times to form a slit on the billet surface. Step S3: Cutting stage: After a slit is formed on the surface of the billet, cut back and forth 6-8 times to cut the billet online without stopping the machine.
2. The method for emergency handling of large-section cast billets that cannot be cut as described in claim 1, characterized in that, During ignition, point A on the surface edge of the billet is the starting position, and the billet is ignited at point A. During the grooving stage: the angle between the replaceable oxygen tube of the billet-specific torch and the billet is 15-20°. Using the billet-specific torch, the torch is moved at a constant speed from point A to point B on the billet, and then returned from point B to point A. This back-and-forth cutting of the billet surface is repeated 1-2 times, forming a slit on the billet surface. The line connecting points A and B represents the width direction of the billet. Points A and B are the points on the two length directions of the upper surface of the billet, and the distance between points A and B is equal to the width of the billet.
3. The method for emergency handling of large-section cast billets that cannot be cut, as described in claim 1, is characterized in that... Cutting stage: After a kerf is formed on the surface of the billet, at the starting position A, adjust the angle between the special torch for firing the billet and the surface of the billet to 15-20°, and then move it at a constant speed from point A to point B. When the propane cutting torch moves to point B, adjust the angle between the special torch for firing the billet and the billet to 30-45°, and then move it at a constant speed from point B to point A. Repeat this cutting back and forth 6-8 times, with the angle between the special torch for firing the billet and the surface of the billet being 15-20° each time from point A to point B. On the return trip, from point B to point A, the angle between the sintering torch and the surface of the billet is 30-45° until the billet is cut off online.
4. The emergency treatment method for large-section cast billets that cannot be cut as described in claim 1, characterized in that, When the replaceable oxygen tube of the sintering gun melts and is damaged during the cutting of the slab, a new replaceable oxygen tube should be installed.
5. The method for emergency handling of large-section cast billets that cannot be cut as described in claim 1, characterized in that, The pressure of the high-pressure oxygen source is ≥1.0MPa, and the oxygen purity is ≥98%.
6. The method for emergency handling of large-section cast billets that cannot be cut as described in claim 1, characterized in that, The special gun for firing blanks includes: an oxygen hose connected to a high-pressure oxygen source, a handheld tube connected to the oxygen hose, and a replaceable oxygen tube detachably connected to the handheld tube, wherein the oxygen hose is equipped with an adjustment valve.
7. The emergency treatment method for large-section cast billets that cannot be cut as described in claim 6, characterized in that, The handheld tube is 60-70cm long, and the replaceable oxygen tube is 250-300cm long.
8. The method for emergency handling of large-section cast billets that cannot be cut as described in claim 1, characterized in that, During the cutting process, the oxygen flow rate of the special torch for firing the blank is 80-100L / min.
9. The method for emergency handling of large-section cast billets that cannot be cut as described in claim 1, characterized in that, The billet has a rectangular cross-section, and the dimensions of the billet cross-section are: thickness of 150-300mm and width of 900-2000mm.