Control method for wind power steel continuous casting B-type inclusions

Abstract

The invention belongs to the technical field of wind power steel production through continuous casting machines, and particularly discloses a control method for wind power steel continuous casting B-type inclusions. A tundish covering agent is replaced by optimizing a sealing structure and an insertion depth of a steel ladle long nozzle, an insertion depth of a submersed nozzle and argon blowing parameters among the steel ladle long nozzle, a stopper rod, an upper nozzle and plates, the degree of superheat of molten steel, the pouring pulling speed and the steel ladle preparation time are controlled, and precise control over the liquid level of a crystallizer and quantitative adding of carbonized rice hulls are used as auxiliary materials. And stable control over the B-type inclusions in the wind power steel continuous casting process is achieved. The problem that when a current wide and thick plate continuous casting machine is used for producing wind power steel, the continuous casting protection pouring effect is not stable, and the control stability of B-type inclusions in the steel is poor is solved. By systematically optimizing nozzle structure parameters, a full-flow protection pouring process, multi-node argon blowing parameters and molten steel pouring key process indexes, a continuous casting process parameter system adaptive to wind power steel production is obtained, and the stability of a continuous casting protection pouring effect is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of continuous casting machine production of wind power steel, specifically to a method for controlling Class B inclusions in continuous casting of wind power steel. Background Technology

[0002] As a core component of clean energy, wind power generation has experienced rapid development globally. The safety and reliability of wind turbine equipment have become critical requirements for the industry's development, and the quality control of wind turbine steel, a core material for wind turbine equipment, is particularly important. Wind turbine steel plates must meet the highest-level flaw detection standard, with stringent requirements for controlling Class B inclusions in the steel. If the control of Class B inclusions in the steel is unstable and exceeds the standard, it will directly lead to defects in the rolled steel plate, resulting in unqualified flaw detection, and consequently, product downgrading or reassessment. This not only fails to meet the quality requirements of downstream users but also significantly increases the production and manufacturing costs of wind turbine steel.

[0003] Currently, when producing wind power steel using heavy plate continuous casting machines in steel mills, the Al content in the steel needs to be precisely controlled within the range of 0.02% to 0.04%. However, the control system for the protective casting process is imperfect. The existing protective casting argon gas is only controlled by a single indicator, the flow rate, which cannot stably achieve the protective casting effect. This not only leads to poor stability in controlling Class B inclusions in the steel, but also, in severe cases, causes problems such as continuous casting nodules and unstable control of the liquid steel level in the crystallizer. At the same time, the control of Al in the continuous casting process has not formed a process parameter system adapted to heavy plate continuous casting equipment, making it difficult to stably control Class B inclusions in the continuously cast billet within the standard range. Summary of the Invention

[0004] The purpose of this invention is to provide a method for controlling Class B inclusions in continuous casting of wind power steel, in order to solve the problems of unstable casting protection and pouring effect in the current production of wind power steel by heavy plate continuous casting machines, which leads to poor stability in the control of Class B inclusions in the steel, and easily causes continuous casting nodules and unstable control of the liquid steel level in the crystallizer.

[0005] To achieve the above objectives, the basic solution provided by this invention is: a method for controlling Class B inclusions in continuous casting of wind power steel. This method optimizes the sealing structure and insertion depth of the long nozzle in the ladle, the insertion depth of the submerged nozzle, the argon blowing parameters of the long nozzle, stopper rod, upper nozzle, and plate, replaces the tundish covering agent, controls the superheat of molten steel, the casting speed and ladle preparation time, and supplements it with precise control of the crystallizer liquid level and quantitative addition of carbonized rice husks. This method achieves stable control of Class B inclusions in the continuous casting process of wind power steel.

[0006] The beneficial effects of this invention are as follows: Addressing the process pain points in producing wind power steel using heavy plate continuous casting machines, this invention systematically optimizes the gate structure parameters, the entire process of protective casting, multi-node argon blowing parameters, and key process indicators for molten steel casting. This results in a continuous casting process parameter system adapted to wind power steel production, effectively improving the stability of the continuous casting protective casting effect. It precisely controls the Al content in wind power steel within the target range of 0.02% to 0.04%, solving the problem of unstable control of Class B inclusions in the steel. This ensures that Class B inclusions in the continuously cast billet consistently meet the requirements of the special grade 1 flaw detection standard, improving the first-pass yield of wind power steel and effectively reducing product downgrading and re-judgment. This not only ensures the stable quality of wind power steel products to meet the needs of downstream users but also significantly reduces the manufacturing cost of wind power steel production.

[0007] Option 2, an optimized version of the basic option, controls the thickness of the long ladle nozzle sealing gasket to 5mm, the insertion depth of the long ladle nozzle to 300-400mm, and the insertion depth of the submerged nozzle to 160-175mm. Increasing the thickness of the long ladle nozzle sealing gasket from 3mm to 5mm improves the tight fit between the ladle nozzle, sealing gasket, and long ladle nozzle after installation, reducing air intake. Adjusting the insertion depth of the long ladle nozzle from 200-300mm to 300-400mm improves the stability of the impact zone in the tundish, reducing slag entrainment caused by unstable molten steel levels in the impact zone. Adjusting the insertion depth of the submerged nozzle from 140-160mm to 160-175mm ensures the stability of the molten steel level in the crystallizer under a certain argon blowing rate.

[0008] Option 3, an optimal choice from the basic option, controls the argon flow rate at the long nozzle of the ladle to be 150 L / min, with a back pressure of 100–150 kPa; the argon flow rate at the stopper rod to be 5 L / min, with a back pressure of 2–10 kPa; the argon flow rate at the upper nozzle to be 3 L / min, with a back pressure of 20–40 kPa; the argon flow rate between plates to be 8–10 L / min, with a back pressure of 10–30 kPa; and the argon flow rate at the refractory cover of the tundish to be 2000 L / min before startup, which is adjusted to 200 L / min after the covering agent is added.

[0009] Option 4, which is the preferred option of the basic option, uses carbonized rice husks as the tundish covering agent. The superheat of the molten steel in the tundish is controlled at 10-30°C, and the casting speed is kept constant during the casting process. The tundish covering agent uses carbonized rice husks instead of the original high-alkalinity covering agent, which improves the heat preservation and covering effect of the molten steel in the tundish.

[0010] Option 5, an optimal choice from the basic option, involves controlling the ladle preparation time to 5–15 minutes. During casting, the amount of carbonized rice husks added is controlled according to the black liquor level to prevent leakage of molten steel. When the tundish is 10 tons of molten steel, 10 bags of carbonized rice husks are added to the stopper bar area. When the tundish is 20 tons of molten steel, 10 bags of carbonized rice husks are added to the impact area. The ladle preparation time is controlled to 5–15 minutes to ensure a stable production rhythm for continuous casting.

[0011] Option 6, which is the preferred option of the basic option, uses the bulging compensation function of the automatic control system for the liquid level in the crystallizer to control the fluctuation of the liquid steel level in the crystallizer within the range of -3 to 3 mm. Detailed Implementation

[0012] The present invention will be further described in detail below through specific embodiments: A method for controlling Class B inclusions in continuous casting of wind power steel is disclosed. This method optimizes the sealing structure and insertion depth of the long nozzle in the ladle, the insertion depth of the submerged nozzle, the argon blowing parameters of the long nozzle, stopper rod, upper nozzle, and plate, replaces the tundish covering agent, controls the superheat of the molten steel, adjusts the pouring speed and ladle preparation time, and supplements this with precise control of the crystallizer liquid level and quantitative addition of carbonized rice husks. The method achieves stable control of Class B inclusions during the continuous casting process of wind power steel. Details are as follows: (1) The thickness of the long nozzle sealing gasket of the ladle is controlled to be 5mm, the insertion depth of the long nozzle of the ladle is controlled to be 300-400mm, and the insertion depth of the submerged nozzle is controlled to be 160-175mm. The thickness of the long nozzle sealing gasket of the ladle is increased from the original 3mm to 5mm, which improves the tight fit between the ladle nozzle, the sealing gasket and the long nozzle of the ladle after installation and reduces air intake. The insertion depth of the long nozzle of the ladle is adjusted from 200-300mm to 300-400mm, which improves the stability of the impact zone in the tundish and reduces the slag entrapment caused by the instability of the molten steel surface in the impact zone. The insertion depth of the submerged nozzle is adjusted from the original 140-160mm to 160-175mm to ensure the stability of the molten steel surface in the crystallizer under a certain argon blowing rate.

[0013] (2) Control the argon blowing flow rate of the long water nozzle of the steel ladle to 150L / min, the back pressure to 100-150KPa, the argon blowing flow rate of the stopper rod to 5L / min, the back pressure to 2-10KPa, the argon blowing flow rate of the upper water nozzle to 3L / min, the back pressure to 20-40KPa, the argon blowing flow rate between plates to 8-10L / min, the back pressure to 10-30KPa, and the argon blowing flow rate of the refractory cover of the tundish to 2000L / min before starting the machine, and adjust it to 200L / min after the covering agent is added; (3) Carbonized rice husks are used as the tundish covering agent. The superheat of the molten steel in the tundish is controlled at 10-30°C, and the casting speed is kept constant during the casting process. Carbonized rice husks are used as the tundish covering agent instead of the original high-alkalinity covering agent, which improves the heat preservation and covering effect of the molten steel in the tundish.

[0014] (4) The preparation time of the ladle is controlled at 5 to 15 minutes. When pouring, the amount of carbonized rice husks added is controlled according to the black liquid level to avoid the leakage of molten steel. When the molten steel in the tundish is 10t, 10 bags of carbonized rice husks are added in the stopper bar area. When the molten steel in the tundish is 20t, 10 bags of carbonized rice husks are added in the impact area. The preparation time of the ladle is controlled at 5 to 15 minutes to ensure a stable production rhythm of continuous casting.

[0015] (5) The automatic control system for the liquid level of the crystallizer is activated with bulging compensation to control the fluctuation of the liquid steel level in the crystallizer within the range of -3 to 3 mm.

[0016] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for controlling Class B inclusions in continuous casting of wind power steel, characterized in that, By optimizing the sealing structure and insertion depth of the long nozzle of the ladle, the insertion depth of the submerged nozzle, the argon blowing parameters of the long nozzle, stopper rod, upper nozzle and plate, replacing the tundish covering agent, controlling the superheat of molten steel, casting speed and ladle preparation time, and supplementing with precise control of the crystallizer liquid level and quantitative addition of carbonized rice husk, stable control of Class B inclusions in the continuous casting process of wind power steel can be achieved.

2. The method for controlling Class B inclusions in continuous casting of wind power steel according to claim 1, characterized in that, The thickness of the sealing gasket for the long nozzle of the ladle is controlled at 5mm, the insertion depth of the long nozzle of the ladle is controlled at 300-400mm, and the insertion depth of the immersion nozzle is controlled at 160-175mm.

3. The method for controlling Class B inclusions in continuous casting of wind power steel according to claim 1, characterized in that, The argon blowing flow rate at the long nozzle of the ladle is controlled at 150 L / min, with a back pressure of 100–150 kPa. The argon blowing flow rate at the stopper rod is 5 L / min, with a back pressure of 2–10 kPa. The argon blowing flow rate at the upper nozzle is 3 L / min, with a back pressure of 20–40 kPa. The argon blowing flow rate between plates is 8–10 L / min, with a back pressure of 10–30 kPa. Before starting the refractory cover of the tundish, the argon blowing flow rate is 2000 L / min, which is adjusted to 200 L / min after the covering agent is added.

4. The method for controlling Class B inclusions in continuous casting of wind power steel according to claim 1, characterized in that, Carbonized rice husks were used as the tundish covering agent, the superheat of the molten steel in the tundish was controlled at 10-30°C, and a constant casting speed was maintained during the casting process.

5. The method for controlling Class B inclusions in continuous casting of wind power steel according to claim 1, characterized in that, The preparation time for the ladle is controlled at 5 to 15 minutes. During casting, the amount of carbonized rice husks added is controlled according to the black liquor level. When the molten steel in the tundish is 10t, 10 bags of carbonized rice husks are added in the stopper rod area. When the molten steel in the tundish is 20t, 10 bags of carbonized rice husks are added in the impact area.

6. The method for controlling Class B inclusions in continuous casting of wind power steel according to claim 1, characterized in that, The automatic control system for the liquid level in the crystallizer uses bulging compensation to control the fluctuation of the liquid steel level in the crystallizer within the range of -3 to 3 mm.