A method for improving ladle self-opening rate

Abstract

The application discloses a method for improving ladle self-opening rate, and adopts a ladle stopper with the following structure: the stopper head of the ladle stopper is shaped to match the ladle upper nozzle base brick, and the two can be tightly attached; the ladle stopper is provided with a gas passage, the lower end of the gas passage penetrates the stopper head, and the upper end of the gas passage is connected with an inert gas pipeline; before the converter tapping, the ladle stopper is installed, the stopper head of the ladle stopper is attached to the ladle upper nozzle base brick, and no drainage sand is added in the ladle upper nozzle base brick; during the tapping process of the converter process, the LF refining and the continuous casting process, inert gas is continuously injected through the gas passage of the ladle stopper; during the continuous casting process, the ladle slide is opened first, and then the ladle stopper is lifted before the ladle casting. The method can greatly improve the ladle self-opening rate, meanwhile, the ladle drainage sand is cancelled, the oxygen burning drainage is prevented, the secondary oxidation of molten steel and the risk of slag entrapment are eliminated, the cleanliness of the molten steel is greatly improved, and the production cost and the safety hidden danger are reduced.

Description

Technical Field

[0001] This invention relates to the field of continuous casting technology in iron and steel metallurgy, and in particular to a method for improving the self-opening rate of steel ladles. Background Technology

[0002] Automatic ladle opening refers to the process where, during ladle opening, the ladle slide gate opens, allowing molten steel to flow naturally from the ladle into the tundish. Drainage sand is placed inside the ladle nozzle, forming a three-layer structure: a molten layer closest to the molten steel, a sintered layer in the middle, and the original, unchanged drainage sand at the bottom. When the slide gate opens, the unchanged drainage sand falls naturally under gravity, while the sintered layer breaks under the static pressure of the molten steel, allowing the molten steel to flow out of the nozzle, achieving the purpose of automatic opening. In actual production, the ladle drainage sand is easily affected by storage environment and operating conditions, leading to abnormalities such as moisture absorption, caking, and sintering, causing it to lose its auxiliary drainage function and resulting in a low ladle self-opening rate. When automatic opening of the ladle is not possible, operators must frequently use oxygen-based drainage methods to force opening. This operation not only causes secondary oxidation of the molten steel but can also, in severe cases, disrupt the pouring rhythm and cause pouring to stop.

[0003] Therefore, developing a method to improve the ladle self-opening rate and avoid the defects of traditional diversion process is of great practical significance for stabilizing the continuous casting production process and improving product quality. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for improving the self-opening rate of steel ladles, so as to improve the cleanliness of molten steel.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention uses a ladle stopper rod with the following structure: the shape of the rod head of the ladle stopper rod matches the upper water outlet seat brick of the ladle, and the two can fit tightly together; the ladle stopper rod is provided with a gas channel, the lower end of the gas channel passes through the rod head, and the upper end is connected to an inert gas pipeline. Before tapping from the converter, a ladle stopper is installed, with the head of the stopper fitting against the upper nozzle seat brick of the ladle, and no guiding sand is added to the upper nozzle seat brick. During the tapping process in the converter, the LF refining process, and the continuous casting process, inert gas is continuously injected through the gas channel of the ladle stopper. In the continuous casting process, before pouring from the ladle, the ladle slide is opened first and then the ladle stopper is raised.

[0006] Furthermore, during the tapping process in the converter process, the pressure of the inert gas is 0.30–0.50 MPa, the pressure of the inert gas is 0.10–0.30 MPa in the LF refining process, and the pressure of the inert gas is 0.40–0.60 MPa in the continuous casting process.

[0007] Furthermore, during the tapping process in the converter process, the flow rate of the inert gas is 5-10 L / min, the flow rate of the inert gas during the LF refining process is 1.0-3.0 L / min, and the flow rate of the inert gas during the continuous casting process is 3.0 L / min-8.0 L / min.

[0008] Furthermore, after the head of the ladle stopper rod is fitted with the ladle water inlet seat brick, the fitting gap is <1mm.

[0009] The beneficial effects of adopting the above technical solution are as follows: By eliminating the ladle guide sand, the present invention avoids the ladle self-opening caused by sintering and other reasons. By using a ladle stopper rod to block the tap hole and combining it with argon blowing to form a diffused gas curtain to prevent sporadic molten steel from seeping in and solidifying, the ladle self-opening rate can be greatly improved. The ladle self-opening rate can be increased to 100% compared to the conventional method of 97.5%. At the same time, eliminating the ladle guide sand can eliminate oxygen-induced flow, eliminate the risk of secondary oxidation of molten steel and slag entrapment, greatly improve the cleanliness of molten steel, and reduce production costs and safety hazards. Attached Figure Description

[0010] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0011] Figure 1 This is a schematic diagram of the structure of the steel ladle stopper rod and the upper water outlet seat brick of the steel ladle described in this invention.

[0012] In the diagram: 1. Ladle stopper rod; 2. Gas passage; 3. Ladle top nozzle seat brick; 4. Ladle slide plate. Detailed Implementation

[0013] This method for improving the self-opening rate of the ladle employs a ladle stopper rod with the following structure: the rod head shape of the ladle stopper rod 1 matches the upper nozzle seat brick 3 of the ladle, allowing for a tight fit with a gap of <1mm; the ladle stopper rod 1 is equipped with a gas channel 2, the lower end of which passes through the rod head, and the upper end which connects to an inert gas pipeline. The upper part of the ladle stopper rod 1 extends out of the ladle. A stopper rod control structure can also be provided for lifting, pressing down, and aligning the ladle stopper rod 1.

[0014] This method for improving the ladle self-opening rate includes converter, refining, and continuous casting processes, as described below: (1) Converter process: Before tapping steel from the converter, install the ladle stopper rod, and fit the rod head of the ladle stopper rod with the ladle top nozzle seat brick with a fitting gap of <1mm, and do not add diverting sand into the ladle top nozzle seat brick; during the tapping process, inert gas is continuously sprayed through the gas channel of the ladle stopper rod; the spraying pressure of the inert gas is 0.30~0.50MPa and the flow rate is 5~10L / min, and argon is preferred as the inert gas.

[0015] (2) LF refining process: The ladle is transferred to the refining station, and inert gas is continuously injected during the transfer process; the ladle enters the refining furnace for refining. Before the refining begins, the pressure and flow rate of the inert gas injected through the stopper are adjusted. Inert gas is continuously injected through the gas channel of the ladle stopper throughout the refining process; the injection pressure of the inert gas is 0.10-0.30 MPa and the flow rate is 1.0-3.0 L / min. Argon is preferred as the inert gas.

[0016] (3) Continuous casting process: The ladle is transferred to the continuous casting station, and inert gas is continuously sprayed during the transfer process; before the ladle starts casting, the long nozzle of the ladle is installed, the ladle slide is opened first and then the ladle stopper is raised; before the start of casting, the pressure and flow rate of the inert gas sprayed through the stopper are adjusted, and inert gas is continuously sprayed through the gas channel of the ladle stopper throughout the entire casting and refining process. The pressure of the sprayed inert gas is 0.40~0.60MPa and the flow rate is 3.0L / min~8.0L / min; after the ladle stopper is raised to the position, the molten steel flows out through the ladle upper nozzle, ladle slide and ladle lower nozzle in sequence under the action of gravity. Then, by adjusting the opening of the ladle slide, the ladle steel discharge flow rate is controlled, and finally the successful start of casting is achieved. Example 1

[0017] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, water inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the water inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.3 MPa, and the flow rate to 10 L / min; during the refining process, the blowing pressure is 0.1 MPa, and the flow rate is 3 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is simultaneously adjusted to 0.6 MPa and the argon blowing flow rate is adjusted to 3.0 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting. Example 2

[0018] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, water inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the water inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.5 MPa, and the flow rate to 5 L / min. During the refining process, the blowing pressure is set to 0.3 MPa, and the flow rate to 1 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is adjusted to 0.4 MPa and the argon blowing flow rate is adjusted to 8.0 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting. Example 3

[0019] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the ladle inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.4 MPa, and the flow rate to 6 L / min. During the refining process, the blowing pressure is set to 0.2 MPa, and the flow rate to 2 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is adjusted to 0.5 MPa and the argon blowing flow rate is adjusted to 5.0 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting. Example 4

[0020] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, water inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the water inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.3 MPa, and the flow rate to 5 L / min. During the refining process, the blowing pressure is set to 0.3 MPa, and the flow rate to 2 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is adjusted to 0.6 MPa and the argon blowing flow rate is adjusted to 4.0 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting. Example 5

[0021] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, water inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the water inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.5 MPa, and the flow rate to 10 L / min. During the refining process, the blowing pressure is set to 0.3 MPa, and the flow rate to 3 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is adjusted to 0.6 MPa and the argon blowing flow rate is adjusted to 8.0 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting. Example 6

[0022] Before tapping steel from the converter, a comprehensive inspection and cleaning of the ladle taphole, water inlet, and slide gate is conducted to thoroughly remove cold steel, slag, and debris from the channels, ensuring smooth steel flow. The ladle slide gate is then closed, and no guiding sand is added to the ladle taphole throughout the process. After these preparations, a dedicated ladle stopper is installed inside the ladle. During installation, it is crucial to ensure the stopper is securely installed, accurately positioned, and free from any misalignment or loosening. After installation, confirm that the stopper head is tightly fitted to the water inlet seat brick to prevent molten steel from condensing in the channel gaps and forming cold steel, which could block the tapping channel. When tapping begins, the ladle stopper argon blowing system is activated, injecting argon gas through the gas channel of the stopper. The blowing pressure is set to 0.4 MPa, and the flow rate to 8 L / min; during the refining process, the blowing pressure is 0.3 MPa, and the flow rate is 2.5 L / min. After refining, the ladle is transferred to the continuous casting station for preparation before continuous casting. First, the long nozzle is fitted onto the ladle. Before casting begins, the ladle slide is slowly opened to confirm that the slide opening is normal and there is no obstruction. Then, the ladle stopper is slowly raised. During the raising of the ladle stopper, the argon blowing pressure is adjusted to 0.5 MPa and the argon blowing flow rate is adjusted to 4.5 L / min. After the ladle stopper is raised to the correct position, the molten steel flows out sequentially through the upper nozzle, the ladle slide, and the lower nozzle under the action of gravity. The ladle discharge flow rate is then controlled by adjusting the opening of the ladle slide, ultimately achieving successful casting.

Claims

1. A method for improving the self-opening rate of steel ladles, characterized in that, The steel ladle stopper (1) adopts the following structure: the shape of the rod head of the steel ladle stopper (1) matches the upper water outlet seat brick (3) of the steel ladle, and the two can fit tightly together; the steel ladle stopper (1) is provided with a gas channel (2), the lower end of the gas channel (2) passes through the rod head, and the upper end is connected to the inert gas pipeline; Before tapping steel from the converter, a ladle stopper (1) is installed, and the head of the ladle stopper (1) is attached to the ladle top nozzle seat brick (3), and no diversion sand is added to the ladle top nozzle seat brick (3); during the tapping process, LF refining and continuous casting process in the converter process, inert gas is continuously sprayed through the gas channel (2) of the ladle stopper (1); in the continuous casting process, before the ladle is opened for casting, the ladle slide plate (4) is opened and then the ladle stopper (1) is raised.

2. The method for improving the self-opening rate of steel ladles according to claim 1, characterized in that: During the tapping process in the converter process, the pressure of the inert gas is 0.30-0.50 MPa; during the LF refining process, the pressure of the inert gas is 0.10-0.30 MPa; and during the continuous casting process, the pressure of the inert gas is 0.40-0.60 MPa.

3. The method for improving the self-opening rate of steel ladles according to claim 2, characterized in that: During the tapping process in the converter, the flow rate of the inert gas is 5-10 L / min; the flow rate of the inert gas injected during LF refining is 1.0-3.0 L / min; and the flow rate of the inert gas injected during the continuous casting process is 3.0 L / min-8.0 L / min.

4. A method for improving the self-opening rate of steel ladles according to claim 1, 2 or 3, characterized in that: After the head of the steel ladle stopper (1) is fitted with the steel ladle water outlet seat brick (3), the fitting gap is <1mm.

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