A method of baking a continuous casting tundish

Abstract

The application discloses a baking method of a continuous casting tundish, and belongs to the technical field of continuous casting production of steel and iron. The method realizes precise management and control of the whole process of baking of the tundish through a differentiated baking system, over-time rejection control, full-process cooling protection of a stopper, standardized operation of starting casting, hierarchical standing and hoisting, and definition of responsibility boundaries, significantly improves the baking quality and hoisting safety, reduces the accident rate, and guarantees continuous and stable production of continuous casting. The application aims to overcome problems of non-uniform baking time of the tundish, non-adequate protection, lack of over-time control, no standard for hoisting safety, and fuzzy responsibility boundaries, and provides a baking method of a continuous casting tundish.

Description

Technical Field

[0001] This invention belongs to the field of steel continuous casting production technology, and particularly relates to a method for baking a continuous casting tundish. Background Technology

[0002] The tundish is a key thermal equipment in the continuous casting production process, and its baking quality directly affects the cleanliness of molten steel, the quality of the cast billet, and production safety. Current tundish baking practices suffer from problems such as inconsistent baking times, lack of differentiated management for different types of tundishes, vague criteria for judging excessive baking time, inadequate cooling and protection of stoppers, and the absence of a unified standard for pre-lifting settling time. These issues easily lead to safety hazards and quality defects such as insufficient drying of the tundish lining, secondary oxidation of molten steel, stopper deformation and steel leakage, and molten steel splashing during lifting. Furthermore, unclear shift handover responsibilities can easily lead to management loopholes, making it difficult to meet the requirements of efficient, stable, and safe continuous casting production.

[0003] With the increasing demands for rhythm control, safety assurance, and quality stability in continuous casting production, there is an urgent need for a systematic, standardized, and quantifiable method for baking the tundish. This method should involve a comprehensive, collaborative design encompassing differentiated baking times, overdue time control, process protection, safe hoisting, and accountability. This would enable standardized, safe, and efficient tundish baking operations, fundamentally reducing the risks of insufficient baking, expired baking, and improper hoisting, thus ensuring smooth continuous casting production. Therefore, developing a simple, standardized, and safe method for baking the tundish is of significant practical importance and application value. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of inconsistent baking times, inadequate protection, lack of overdue control, lack of standards for hoisting safety, and unclear responsibility definition in existing tundish baking methods, and to provide a baking method for continuous casting tundishes. This method achieves precise control over the entire tundish baking process through differentiated baking procedures, overdue scrap control, continuous cooling and protection of stoppers, standardized start-up operations, graded static hoisting, and clear shift handover responsibilities. This significantly improves baking quality and hoisting safety, reduces the incidence of production accidents, and ensures continuous and stable continuous casting production.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention discloses a baking method for a continuous casting tundish, comprising the following steps:

[0007] I. Full Process Control of Intermediate Bread Baking

[0008] 1.1) Differentiated baking time control: The normal baking time for non-quick-change intermediate bread is greater than 2.5 hours, and the normal baking time for quick-change intermediate bread is greater than 3.0 hours. It can only be used normally after the baking time is met.

[0009] 1.2) Limitations on use of extended baking time: Baking time exceeding 4.0 hours, casting time not exceeding 600 minutes for medium carbon steel and peritectic steel series, and not exceeding 500 minutes for low carbon steel and low carbon alloy steel series;

[0010] 1.3) Overdue scrapping control: The total baking time of intermediate buns shall not exceed 6.0 hours. If the baking time exceeds 6 hours, the intermediate buns shall be scrapped and the baking operation shall be repeated.

[0011] II. Delineation and Management of Shift Handover Responsibilities

[0012] 2.1) Problems must be reported level by level: Any abnormalities discovered during shift handover must be reported to the outgoing shift personnel level by level;

[0013] 2.2) Division of Responsibilities for Starting Pouring: Pouring shall commence within 30 minutes of shift handover;

[0014] III. Safety Management of Intermediate Ladle Lifting

[0015] 3.1) Pre-lifting inspection: Before the intermediate ladle is unloaded, confirm that the hydraulic cylinder has been disassembled and that there are no sprues or other foreign objects on the ladle cover to prevent it from falling and injuring people during the lifting process;

[0016] 3.2) Lifting route specifications: After the intermediate bale is lifted off the intermediate bale vehicle, it must travel along the safety passage. The crane must sound its horn throughout the entire journey to ensure that no personnel stop or pass through the route.

[0017] 3.3) Control of abnormal watering stoppage and static placement:

[0018] 1) Medium carbon steel, low carbon steel, peritectic steel:

[0019] a) Remaining amount < 40 tons (liquid level 550mm): Let stand for more than 0.5 hours, and hoist only after confirming that the upper part of the molten steel has solidified;

[0020] b) Remaining 40–55 tons (liquid level 550mm–750mm): Let stand for more than 3 hours and confirm that the upper part of the molten steel has solidified before hoisting;

[0021] c) Remaining molten steel > 55 tons (liquid level 750 mm): Let stand for more than 4 hours and confirm that the upper part of the molten steel has solidified before hoisting;

[0022] 2) Silicon steel:

[0023] a) Remaining amount < 40 tons (liquid level 550mm): Let stand for more than 0.5 hours, and hoist only after confirming that the upper part of the molten steel has solidified;

[0024] b) Remaining 40–55 tons (liquid level 550mm–750mm): Let stand for more than 3.5 hours, and hoist only after confirming that the upper part of the molten steel has solidified;

[0025] c) Remaining molten steel > 55 tons (liquid level 750mm): Allow to stand for at least 4.5 hours, and hoisting can only proceed after confirming that the upper part of the molten steel has solidified.

[0026] Furthermore, step one also includes: 1.4) Protection and cooling control before baking: complete the full protection of the intermediate package before baking; during the baking process, the stopper rod connection position must be continuously cooled with compressed air, and there should be no leakage of fire throughout the process.

[0027] Furthermore, step one also includes: 1.5) Removal of protective measures after pouring: Remove the heat protection around the stopper rod in a timely manner after normal pouring to avoid the protective parts melting and failing due to prolonged high temperature.

[0028] Furthermore, step one also includes: 1.6) Control of covering agent after pouring: After pouring, add sufficient covering agent to the stopper rod area to keep the slag discharge port unobstructed and strictly prevent blockage.

[0029] Furthermore, in step two: if the issue is not handled in a timely manner, the day shift foreman will double the performance evaluation of the shift supervisor, while those who proactively handle the issue will be commended.

[0030] Furthermore, regarding the division of responsibility for starting the pouring: pouring must begin within 30 minutes of the shift handover, and the previous shift personnel shall be fully responsible for any quality and safety issues that arise in the intermediate batch.

[0031] Furthermore, this method enables continuous and smooth production, eliminates tundish-induced failures, increases the billet qualification rate to 99.1%, and significantly reduces rework and accident costs.

[0032] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0033] 1. This invention establishes a differentiated, time-limited, and quantifiable intermediate baking system, clearly defining control standards for quick / non-quick-change bags, different steel types, and different baking times, solving the problems of high arbitrariness and loss of control due to exceeding the time limit in traditional baking, and ensuring baking quality from the source.

[0034] 2. This invention implements full-process cooling of the stopper rod, removal of protective measures after pouring, and control of the covering agent, effectively avoiding failures such as high-temperature burns, fire leaks, and blockages, and improving the stability of tundish operations.

[0035] 3. This invention establishes a graded static hoisting system based on steel type and remaining steel quantity, completely eliminating major safety risks such as molten steel splashing and falling during the hoisting process, and ensuring the safety of personnel and equipment.

[0036] 4. This invention clearly defines the responsibilities and reward / punishment mechanisms for shift handover, enabling problems to be traced and assessed, and improving the standardization and execution of on-site management.

[0037] 5. This method requires no new equipment investment and can be implemented simply through standardized processes and parameter control. It is easy to operate, highly applicable, and can be widely used in various continuous casting production lines, with significant safety and economic benefits. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments.

[0039] Example 1

[0040] A method for baking a continuous casting tundish, comprising the following steps:

[0041] 1. Intermediate Tundish Baking Control: A non-quick-change intermediate tundish is used, with a baking time of 3.2 hours, meeting the requirement of more than 2.5 hours; the stopper rod connection is cooled by compressed air throughout the baking process to prevent fire leakage; the heat protection is removed in time after pouring, the stopper rod area is adequately covered with a covering agent, and the slag discharge port is unobstructed.

[0042] 2. Extended baking time control: The total baking time was 4.5 hours, which did not exceed the 6-hour scrapping line; the casting time for medium carbon steel was controlled within 580 minutes, which met the requirements.

[0043] 3. Shift handover management: If there are no abnormal issues during this shift, the handover will proceed normally; watering will begin 20 minutes after the handover, and this shift will be responsible for maintaining stable watering.

[0044] 4. Lifting and transportation control: Normally stop pouring, remove the hydraulic cylinder before unloading, and ensure the cover is free of foreign objects; lift along the safety passage, sound the horn throughout the process, and ensure no personnel enter the path.

[0045] Production in this batch was stable, with no issues such as deformation, steel leakage, or blockage in the tundish, and the billet quality was up to standard.

[0046] Example 2

[0047] A method for baking a continuous casting tundish, comprising the following steps:

[0048] 1. Baking control: Quick-change intermediate dough is used, and the baking time is 3.5 hours, which meets the standard of more than 3.0 hours; the stopper is cooled in place during baking and there is no leakage; the covering agent is added in a standardized manner after pouring.

[0049] 2. Abnormal stoppage of pouring and hoisting: When pouring silicon steel, 48 tons remain in the tundish (liquid level 650mm). Let it stand on the tundish car for 3.5 hours to confirm that the upper part of the molten steel has completely solidified before hoisting.

[0050] 3. Shift handover: If minor protective abnormalities are found during shift handover, report and handle them immediately. If no consequences result, record the incident according to the established procedures.

[0051] This embodiment has no safety hazards, the hoisting is smooth, there is no risk of molten steel splashing, and the tundish can be taken off the production line for repair normally.

[0052] Experimental verification and effect analysis:

[0053] To verify the feasibility of the method of the present invention, 20 batches of continuous casting production were selected, of which 10 batches adopted the traditional baking method (control group) and 10 batches adopted the systematic baking method of the present invention (experimental group). The baking quality of the tundish, the accident rate and production stability were compared. The results are as follows: 1. Baking and usage effect: In the control group, the proportion of insufficient baking and over-use of the tundish was 18%, and the overheating deformation rate of the stopper rod was 12%; The baking qualification rate of the experimental group was 100%, with no failures other than over-use, and the stopper rod was cooled in place without overheating deformation.

[0054] 2. Lifting safety: The control group experienced 2 incidents of molten steel splashing and 1 incident of foreign object falling; the test group had no lifting safety accidents, and the lifting compliance rate was 100%.

[0055] 3. Production stability and cost: The control group experienced four production fluctuations due to issues with the intermediate package, resulting in a yield rate of 93%; the experimental group maintained continuous and smooth production.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for baking a continuous casting tundish, characterized in that: The specific steps include: I. Full Process Control of Intermediate Bread Baking 1.1) Differentiated baking time control: The normal baking time for non-quick-change intermediate bread is greater than 2.5 hours, and the normal baking time for quick-change intermediate bread is greater than 3.0 hours. It can only be used normally after the baking time is met. 1.2) Limitations on use of extended baking time: Baking time exceeding 4.0 hours, casting time not exceeding 600 minutes for medium carbon steel and peritectic steel series, and not exceeding 500 minutes for low carbon steel and low carbon alloy steel series; 1.3) Overdue scrapping control: The total baking time of intermediate buns shall not exceed 6.0 hours. If the baking time exceeds 6 hours, the intermediate buns shall be scrapped and the baking operation shall be repeated. II. Delineation and Management of Shift Handover Responsibilities 2.1) Problems must be reported level by level: Any abnormalities discovered during shift handover must be reported to the outgoing shift personnel level by level; 2.2) Division of Responsibilities for Starting Pouring: Pouring shall commence within 30 minutes of shift handover; III. Safety Management of Intermediate Ladle Lifting 3.1) Pre-lifting inspection: Before the intermediate ladle is unloaded, confirm that the hydraulic cylinder has been disassembled and that there are no sprues or other foreign objects on the ladle cover to prevent it from falling and injuring people during the lifting process; 3.2) Lifting route specifications: After the intermediate bale is lifted off the intermediate bale vehicle, it must travel along the safety passage. The crane must sound its horn throughout the entire journey to ensure that no personnel stop or pass through the route. 3.3) Control of abnormal watering stoppage and static placement: 1) Medium carbon steel, low carbon steel, peritectic steel: a) If the remaining amount is less than 40 tons: let it stand for more than 0.5 hours and confirm that the upper part of the molten steel has solidified before hoisting; b) Remaining 40–55 tons: Let stand for more than 3 hours and confirm that the upper part of the molten steel has solidified before hoisting; c) Remaining amount > 55 tons: Let stand for more than 4 hours and confirm that the upper part of the molten steel has solidified before hoisting; 2) Silicon steel: a) If the remaining amount is less than 40 tons: let it stand for more than 0.5 hours and confirm that the upper part of the molten steel has solidified before hoisting; b) For the remaining 40–55 tons: let it stand for more than 3.5 hours, and only hoist it after confirming that the upper part of the molten steel has solidified; c) For a remaining amount of more than 55 tons: allow the molten steel to stand for more than 4.5 hours and confirm that the upper part of the molten steel has solidified before hoisting.

2. The baking method for the continuous casting tundish according to claim 1, characterized in that: Step one also includes: 1.4) Protection and cooling control before baking: complete the full protection of the intermediate package before baking; during the baking process, the stopper rod connection must be continuously cooled with compressed air, and there should be no leakage of fire throughout the process.

3. The baking method for the continuous casting tundish according to claim 2, characterized in that: Step one also includes: 1.5) Removal of protective measures after pouring: Remove the heat protection around the stopper rod in time after normal pouring to avoid the protective parts melting and failing due to prolonged high temperature.

4. The baking method for the continuous casting tundish according to claim 3, characterized in that: Step one also includes: 1.6) Control of covering agent after pouring: After pouring, add sufficient covering agent to the stopper rod area to keep the slag discharge port unobstructed and strictly prevent blockage.

5. The baking method for the continuous casting tundish according to claim 1, characterized in that: In step two: if the issue is not handled in a timely manner, the day shift foreman will double the performance evaluation of the shift supervisor, while those who take the initiative to handle the issue will be commended.

6. The baking method for the continuous casting tundish according to claim 1, characterized in that: The division of responsibility for starting the pouring is as follows: Pouring must begin within 30 minutes of the shift handover. Any quality or safety issues that arise in the intermediate batches will be the sole responsibility of the personnel from the previous shift.

7. The baking method for the continuous casting tundish according to claim 1, characterized in that: This method enables continuous and smooth production, eliminates intermediate ladle-induced failures, increases the billet qualification rate to 99.1%, and significantly reduces rework and accident costs.