阅读说明：本技术 一种减少亚包晶钢生产中液位波动的控制方法 (Control method for reducing liquid level fluctuation in production of sub-peritectic steel ) 是由 潘统领 杜林� 高立超 王一名 宋玉 李玉德 于 2021-09-13 设计创作，主要内容包括：本发明涉及亚包晶钢生产技术领域,尤其涉及一种减少亚包晶钢生产中液位波动的控制方法。1)采取如下措施减弱包晶反应：A、控制精炼加热时间≤10min；B、精炼进站补加合金,控制补加合金量小于1.5kg/t；C、精炼结束时控制碳含量；2)针对结晶器内坯壳均匀生长,采取如下措施：A、提高钢水过热度,控制在20℃～50℃；B、保护渣碱度不低于1.35；C、结晶器水缝流速控制在6.0m/s～8.0m/s；D、拉速恒定；3)针对二冷段内铸坯鼓肚,采取如下措施：A、生产前铸机辊缝±0.5mm,控制辊缝合格率；B、水嘴堵塞率不大于2％；C、增加二冷水强度,二冷比水量≥0.9kg/t。本发明使亚包晶钢生产液位波动降低70％以上,保证生产稳定顺行。(The invention relates to the technical field of hypo-peritectic steel production, in particular to a control method for reducing liquid level fluctuation in hypo-peritectic steel production. 1) The peritectic reaction is weakened by adopting the following measures: A. controlling the refining heating time to be less than or equal to 10 min; B. refining and feeding alloy, and controlling the amount of the alloy to be fed to be less than 1.5 kg/t; C. controlling the carbon content when the refining is finished; 2) aiming at the uniform growth of a blank shell in a crystallizer, the following measures are adopted: A. improving the superheat degree of the molten steel, and controlling the superheat degree to be 20-50 ℃; B. the alkalinity of the covering slag is not lower than 1.35; C. controlling the flow rate of a water gap of the crystallizer to be 6.0-8.0 m/s; D. the pulling speed is constant; 3) aiming at the bulging of the casting blank in the secondary cooling section, the following measures are taken: A. before production, the roll gap of the casting machine is +/-0.5 mm, and the pass percent of the roll gap is controlled; B. the water nozzle blockage rate is not more than 2%; C. the strength of secondary cooling water is increased, and the specific water amount of the secondary cooling water is more than or equal to 0.9 kg/t. The invention reduces the liquid level fluctuation of the hypo-peritectic steel production by more than 70 percent and ensures the stable and smooth production.)

1. A control method for reducing liquid level fluctuation in subcontracting steel production is characterized by specifically comprising the following steps:

1) the peritectic reaction is weakened by adopting the following measures:

A. controlling the refining heating time to be less than or equal to 10 min;

B. refining and feeding alloy, and controlling the amount of the alloy to be fed to be less than 1.5 kg/t;

C. controlling the carbon content when the refining is finished;

2) aiming at the uniform growth of a blank shell in a crystallizer, the following measures are adopted:

A. improving the superheat degree of the molten steel, and controlling the superheat degree to be 20-50 ℃;

B. the alkalinity of the covering slag is not lower than 1.35;

C. controlling the flow rate of a water gap of the crystallizer to be 6.0-8.0 m/s;

D. the pulling speed is constant;

3) aiming at the bulging of the casting blank in the secondary cooling section, the following measures are taken:

A. before production, the roll gap of the casting machine is +/-0.5 mm, and the pass percent of the roll gap is controlled;

B. the water nozzle blockage rate is not more than 2%;

C. the strength of secondary cooling water is increased, and the specific water amount of the secondary cooling water is more than or equal to 0.9 kg/t.

2. The control method for reducing the fluctuation of the liquid level in the production of the hypo-peritectic steel as claimed in claim 1, wherein the carbon content at the end of refining in the step 1) C is controlled to be 0.09% -0.11%.

3. The control method for reducing the liquid level fluctuation in the production of the hypo-peritectic steel according to claim 1, wherein the step 3) A is to control the pass rate of the roll gap to be not less than 90%.

Technical Field

The invention relates to the technical field of hypo-peritectic steel production, in particular to a control method for reducing liquid level fluctuation in hypo-peritectic steel production.

Background

The subcontracting steel is common carbon steel with the carbon content of 0.07-0.17%, and is in a peritectic region (L + delta-gamma) in the casting solidification process, peritectic phase change is easy to occur to cause volume shrinkage, the uneven volume shrinkage causes uneven thickness of a blank shell, and the generated bulging is continuously extruded in a fan-shaped section of a continuous casting machine, so that liquid level fluctuation of a crystallizer is continuously increased, the quality of a casting blank is influenced, and even steel leakage occurs in severe cases.

At present, the main control means is to reduce the drawing speed and increase the thickness of the blank shell. Although the liquid level fluctuation can be relieved, the liquid level fluctuation still can be generated, and the production is seriously influenced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a control method for reducing liquid level fluctuation in hypo-peritectic steel production, so that the liquid level fluctuation in the hypo-peritectic steel production is reduced, and the stable and smooth production is ensured.

In order to achieve the purpose, the invention adopts the following technical scheme:

a control method for reducing liquid level fluctuation in subcontracting steel production specifically comprises the following steps:

1. aiming at the peritectic reaction, controlling the carbon content and weakening the peritectic reaction, the following measures are adopted:

1) the refining heating time is reduced and controlled to be less than or equal to 10 min.

2) The amount of the alloy added during refining is less than 1.5kg/t, and the carburization amount influenced by the alloy is reduced.

3) The narrow range of the carbon component is controlled according to +/-0.005 percent, so that the carbon content avoids a severe peritectic reaction interval as much as possible, and is usually 0.09 to 0.11 percent.

2. Aiming at the uniform growth of a blank shell in a crystallizer, the following measures are adopted:

1) the superheat degree of the molten steel is improved and controlled at 20-50 ℃.

2) The alkalinity of the high-alkalinity casting powder is not lower than 1.35, and the casting blank is uniformly cooled in the crystallizer.

3) The flow velocity of the water gap of the crystallizer is controlled to be 6.0-8.0 m/s.

4) The drawing speed is controlled to be constant, and the stable and uniform growth of the shell thickness of the blank is ensured.

3. Aiming at the bulging of the casting blank in the secondary cooling section, the following measures are taken:

1) the roll gap is controlled to be +/-0.5 mm, so that the percent of pass is not less than 90 percent.

2) The water nozzle blockage rate is controlled to be not more than 2%, the phenomenon that the cooling strength is insufficient due to blockage is avoided, and the blank shell is thin and bulges to extrude to form liquid level fluctuation.

3) The strength of secondary cooling water is increased, and the specific water quantity is controlled to be more than or equal to 0.9 kg/t.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts effective measures aiming at peritectic reaction, controlling carbon content, weakening peritectic reaction, uniform growth of a blank shell in a crystallizer and bulging of a casting blank in a secondary cooling section, so that the fluctuation of the production liquid level of the hypo-peritectic steel is reduced by more than 70 percent, and the stable and smooth production is ensured.

Detailed Description

The invention discloses a control method for reducing liquid level fluctuation in hypo-peritectic steel production. Those skilled in the art can modify the process parameters appropriately to achieve the desired results with reference to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

A control method for reducing liquid level fluctuation in subcontracting steel production specifically comprises the following steps:

1. aiming at the peritectic reaction, controlling the carbon content and weakening the peritectic reaction, the following measures are adopted:

1) the refining heating time is reduced and controlled to be less than or equal to 10 min.

2) The amount of the alloy added during refining is less than 1.5kg/t, and the carburization amount influenced by the alloy is reduced.

3) The refining control precision is improved, the narrow range of the carbon component is controlled according to +/-0.005 percent, and the carbon content is enabled to avoid the intense peritectic reaction interval as far as possible, and is usually 0.09-0.11 percent.

2. Aiming at the uniform growth of a blank shell in a crystallizer, the following measures are adopted:

1) the superheat degree of the molten steel is improved and controlled at 20-50 ℃.

2) The alkalinity of the high-alkalinity casting powder is not lower than 1.35, and the casting blank is uniformly cooled in the crystallizer.

3) The flow velocity of the water gap of the crystallizer is controlled to be 6.0-8.0 m/s.

4) The drawing speed is controlled to be constant, and the stable and uniform growth of the shell thickness of the blank is ensured.

3. Aiming at the bulging of the casting blank in the secondary cooling section, the following measures are taken:

1) the sector section is reinforced, the qualified rate of roll gaps is improved, the qualified rate of the roll gaps with +/-0.5 mm is not lower than 90%, and liquid level fluctuation caused by bulging extrusion due to poor roll gaps is reduced.

2) The secondary cooling water nozzle inspection is enhanced, the water nozzle blocking rate is not more than 2%, the phenomenon that the cooling strength is insufficient due to blocking is avoided, and the blank shell is thin and bulges to extrude to form liquid level fluctuation.

3) The strength of secondary cooling water is increased, and the specific water amount is more than or equal to 0.9 kg/t.

Example 1:

the invention will be further explained by taking the production of steel grades with a carbon content of 0.08% -0.10% as an example.

A control method for reducing liquid level fluctuation in subcontracting steel production specifically comprises the following steps:

1. refining and heating for 5 min.

2. 0.68kg/t ferrosilicon and 0.64kg/t medium-carbon ferromanganese are added.

3. The carbon content at the end of refining was controlled at 0.083%.

4. The superheat degree of the molten steel is 30 ℃.

5. Mold flux with basicity of 1.35 was used.

6. The flow velocity of the water gap at the wide side of the crystallizer is 6m/s, and the flow velocity at the narrow side of the crystallizer is 7 m/s.

7. The qualification rate of the casting machine roll gap +/-0.5 mm before production is 92 percent.

8. The water nozzle blockage rate is 1.87%.

9. The secondary cooling specific water amount is 0.9 kg/t.

Example 2:

the invention will be further explained by taking the production of steel grades with a carbon content of 0.12-0.14% as an example.

A control method for reducing liquid level fluctuation in subcontracting steel production specifically comprises the following steps:

1. the refining heating time is 6 min.

2. 0.56kg/t ferrosilicon and 0.51kg/t medium-carbon ferromanganese are added.

3. The carbon content at the end of refining was controlled at 0.136%.

4. The superheat degree of the molten steel is 29 ℃.

5. Mold flux with basicity of 1.35 was used.

6. The flow velocity of the water gap at the wide side of the crystallizer is 6m/s, and the flow velocity at the narrow side of the crystallizer is 7 m/s.

7. The qualification rate of roll gap plus or minus 0.5mm of the casting machine before production is 94 percent.

8. The water nozzle blockage rate is 1.92 percent.

9. The secondary cooling specific water amount is 0.9 kg/t.

Example 3:

the invention will be further explained by taking the production of steel grades with a carbon content of 0.10-0.12% as an example.

A control method for reducing liquid level fluctuation in subcontracting steel production specifically comprises the following steps:

1. the refining heating time is 6 min.

2. 0.41kg/t ferrosilicon and 0.51kg/t medium-carbon ferromanganese are added.

3. The carbon content at the end of refining was controlled at 0.118%.

4. The superheat degree of the molten steel is 32 ℃.

5. Mold flux with basicity of 1.35 was used.

6. The flow velocity of the water gap at the wide side of the crystallizer is 6m/s, and the flow velocity at the narrow side of the crystallizer is 7 m/s.

7. The yield of the casting machine roll gap +/-0.5 mm before production is 93 percent.

8. The water nozzle blockage rate is 1.85 percent.

9. The secondary cooling specific water amount is 0.9 kg/t.

The invention adopts effective measures aiming at peritectic reaction, controlling carbon content, weakening peritectic reaction, uniform growth of a blank shell in a crystallizer and bulging of a casting blank in a secondary cooling section, and ensures that the fluctuation of the production liquid level of the hypo-peritectic steel is reduced by 75 percent by the method, thereby ensuring stable and smooth production.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.