Method for blocking tundish upper nozzle by stopper head in automatic pouring process and continuous casting machine

Abstract

The application provides a method for sealing the upper water gap of a tundish by a stopper head in an automatic casting process and a continuous casting machine. The stopper is driven by a servo motor to seal the upper water gap of the tundish. Before the crystallizer starts casting, a torque control method is used to control the torque output by the servo motor to be a constant torque M, and the actual sealing position is smaller than the sealing zero position. The deflection deformation amount of the upper water gap of the tundish caused by the rising of the molten steel can be offset, the stopper can follow the dynamic displacement of the position of the upper water gap of the tundish, and thus the upper water gap of the tundish is always in a tightly sealed state. The gap between the upper water gaps of the tundishes is avoided to prevent liquid seepage or leakage. The method has a good application prospect in continuous casting production.

Description

Technical Field

[0001] This invention belongs to the field of continuous casting process technology in the metallurgical industry, specifically relating to a method for sealing the tundish top nozzle with a stopper rod head during automatic casting. Background Technology

[0002] Automated casting start technology is commonly used in continuous casting production. During automated casting start, before the crystallizer starts casting, a servo motor drives a stopper rod to seal the tundish nozzle. For example... Figure 1 As shown, when the ladle 1 is initially started, molten steel flows into the empty ladle through the ladle nozzle 2. The stopper rod 4 blocks the top nozzle 5 of the tundish. After the molten steel in the tundish exceeds a certain height, after receiving the crystallizer start-up command, the stopper rod 4 is moved by controlling the operation of the servo motor. This adjusts the gap between the stopper rod head 7 and the top nozzle 5 of the tundish to control the size of the steel flow channel and complete the automatic start-up process.

[0003] Currently, before the crystallizer starts casting, the stopper rod is used to seal the top nozzle of the tundish using position control, and the stopper rod head is always kept in the zero-position sealing position. When the ladle and crystallizer are not in operation and there is no molten steel in the tundish, the stopper rod head is in contact with the top nozzle end face, and the gap in the steel flow channel formed between them is zero. The position of the stopper rod head at this time is marked as the zero-position sealing.

[0004] However, the problem with this method is: Figure 4 As shown, before the crystallizer starts casting, the stopper head is kept in the zero-position of the seal. The static pressure of the molten steel rising in the tundish causes the upper nozzle of the tundish to bear a downward force, which can easily cause deflection deformation of the seal structure, leading to the lowering of the upper nozzle (see [link]). Figure 4 (The top nozzle of the tundish has moved from the dotted line position to the solid line position), thus creating a gap between the stopper head and the top nozzle of the tundish. This results in the stopper head not sealing the top nozzle properly, allowing molten steel from the tundish to seep into the crystallizer before casting begins. This situation occurs in... Figure 2 This is especially true in multi-flow tundishes, because when waiting for automatic pouring in the later stages of multi-flow tundishes, the molten steel level in the tundish is high, the static pressure of the molten steel increases accordingly, and the degree of deflection and deformation of the sealing structure increases. Summary of the Invention

[0005] In view of the above-mentioned technical situation, the present invention provides a method for sealing the tundish nozzle with a stopper rod head during automatic casting. By using this method, the stopper rod head tightly seals the tundish nozzle before casting begins in the crystallizer, which can avoid the steel leakage problem that occurs when using a position-controlled stopper rod to seal the tundish nozzle.

[0006] The technical solution provided by this invention is: a method for sealing the upper water inlet of a middle casing using a stopper rod head during automatic pouring, characterized in that: a servo motor drives the stopper rod to seal the upper water inlet of the middle casing; the greater the torque value of the servo motor in the sealing state, the greater the pressing force of the stopper rod head on the upper water inlet; torque control is adopted, and the torque of the servo motor is kept constant at a constant torque M in the sealing state, and the actual sealing position is less than the sealing zero position; the actual sealing position refers to the position value of the stopper rod head when it is stationary under the action of the constant torque M, with the sealing zero position as the reference value; if the stopper rod moves downward, the actual sealing position decreases, and vice versa.

[0007] In this invention, the motor outputs torque, which is then transmitted to the stopper rod via a transmission mechanism to deliver linear pressure. Therefore, the motor structure is not limited, and any motor capable of outputting linear pressure can be used in this invention.

[0008] In this invention, before the crystallizer starts casting, the sealing of the tundish nozzle by the stopper rod using this method is as follows: When the ladle is first used for pouring, but the crystallizer is not yet used, and there is no molten steel in the tundish, if Figure 5 As shown, the servo motor has a constant torque M, which outputs linear pressure to the stopper rod. The stopper rod displacement blocks the upper water inlet of the tundish, generating a sufficiently large clamping force on the upper water inlet of the tundish, so that the actual blocking position is less than the zero blocking position. As long as the crystallizer is not in operation, the stopper rod head maintains a certain clamping force on the upper water inlet, always ensuring that the actual blocking position is less than the zero blocking position.

[0009] As the molten steel level in the tundish rises, the static pressure of the molten steel causes deflection deformation at the tundish's top nozzle. If a traditional position control method is used, the stopper head's position remains unchanged, leading to a decrease in the actual clamping force of the stopper head on the top nozzle, which can easily cause steel leakage. However, this invention, before the crystallizer starts casting, uses torque control to maintain a constant torque M on the servo motor. When the actual clamping force decreases, the stopper head automatically moves downward until the actual clamping force returns to normal. Therefore, the stopper head dynamically moves with the position of the tundish's top nozzle, which can offset the deflection deformation of the tundish's top nozzle, ensuring that the tundish's top nozzle is always in a tightly sealed state.

[0010] Compared with existing technologies, this invention uses a servo motor to drive a stopper rod to seal the tundish nozzle before the crystallizer starts casting. Specifically, the servo motor outputs torque, which, through a transmission mechanism, delivers linear pressure to the stopper rod to seal the tundish nozzle. This process employs a torque control method, controlling the servo motor's output torque to be a constant torque M, delivering linear pressure to the stopper rod to seal the tundish nozzle. The stopper rod head maintains a constant pressure on the nozzle, ensuring the actual sealing position is always less than the zero-position. This counteracts the deflection deformation of the tundish nozzle caused by the rising molten steel, allowing the stopper rod to dynamically move with the tundish nozzle, thus ensuring the tundish nozzle remains tightly sealed. This solves the problem of leakage or seepage that easily occurs between the stopper rod head and the tundish nozzle when using position control in existing technologies, as the molten steel rises. This invention can be applied to continuous casting machines and has good prospects for widespread application in continuous casting production. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the main equipment of the present invention.

[0012] Figure 2 This is a schematic diagram of the multi-flow casting method in this invention.

[0013] Figure 3 yes Figure 2 Enlarged view of the sealing structure in the image.

[0014] Figure 4 This is a schematic diagram illustrating the problems that arise when using a position control stopper rod to seal the water inlet of the middle liner before the crystallizer starts pouring.

[0015] Figure 5 This is a schematic diagram of the process of using a torque-controlled stopper rod to seal the water inlet of the middle package before the crystallizer is started to pour water in the present invention.

[0016] Figures 1 to 3 The numbers in the package are: 1. Large package nozzle 2. Medium package 3. Stopper rod 4. Medium package upper nozzle 5. Sealing structure 6. Stopper rod head 7. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are still within the protection scope of the present invention.

[0018] The terms "including" and similar words used in this specification should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0019] like Figure 1As shown, the continuous casting machine includes a ladle 1, a tundish 3, and a crystallizer, and employs automated casting technology to organize production. Before casting begins in the crystallizer, a servo motor drives a stopper rod 4 to block the tundish's upper nozzle 5. Figure 1 As shown, when the ladle 1 is initially started, molten steel flows into the empty ladle 3 through the ladle nozzle 2. The stopper rod 4 blocks the top nozzle 5 of the tundish. After the molten steel in the tundish exceeds a certain height, after receiving the crystallizer start-up command, the stopper rod 4 is moved by controlling the operation of the servo motor. This adjusts the gap between the stopper rod head 7 and the top nozzle 5 of the tundish to control the size of the steel flow channel and complete the automatic start-up process.

[0020] Before the crystallizer starts pouring, the servo motor drives the stopper rod 4 to seal the upper sprue nozzle 5 of the sprue. The greater the torque value of the servo motor in the sealing state, the greater the clamping force of the stopper rod head 7 on the upper sprue nozzle 5 of the sprue. Taking the zero sealing position as the reference value, the position where the stopper rod head is stationary under the torque of the servo motor is the actual sealing position. If the stopper rod moves downward, the actual sealing position decreases, and vice versa.

[0021] like Figure 5 As shown, before the crystallizer starts casting, the stopper rod 4 is used to block the sprue nozzle 5 of the tundish using torque control. That is, the torque of the servo motor is kept constant M during the blocking state, and the actual blocking position is less than the zero blocking position. Using this method, the blocking of the sprue nozzle of the tundish by the stopper rod before the crystallizer starts casting is as follows: When the ladle is initially used for casting, but the crystallizer is not yet in operation and there is no molten steel in the tundish, the servo motor operates at a constant torque M, outputting linear pressure to the stopper rod. The stopper rod displaces to seal the tundish's upper nozzle, generating sufficient clamping force to ensure the actual sealing position is less than the zero-position. Furthermore, as long as the crystallizer is not in operation, the stopper rod head maintains a consistent clamping force on the upper nozzle, always ensuring the actual sealing position is less than the zero-position. As the molten steel level in the tundish continues to rise, the static pressure of the molten steel causes deflection deformation of the tundish's upper nozzle (see...). Figure 5 As the tundish inlet moves from the dotted line to the solid line, the stopper rod automatically moves down when the actual clamping force decreases until the actual clamping force returns to normal. Therefore, the stopper rod dynamically moves along with the position of the tundish inlet (see [link]). Figure 5 The actual sealing position is moved downward, that is, the stopper head moves down from the position of the dotted hollow circle to the position of the solid circle. This can offset the deflection deformation of the tundish top nozzle, so that the tundish top nozzle is always in a tight sealing state. This solves the problem of leakage or seepage that easily occurs between the stopper head and the tundish top nozzle when the position control is used in the prior art as the molten steel in the tundish rises.

Claims

1. A method for sealing the water inlet of the intermediate casing using a stopper rod head during automatic pouring, characterized by: The servo motor drives the stopper rod to seal the upper water inlet of the middle package. The greater the torque value of the servo motor in the sealing state, the greater the clamping force of the stopper rod head on the upper water inlet. Torque control is adopted to maintain a constant torque M of the servo motor in the blocking state, and the actual blocking position is less than the blocking zero position; The actual sealing position refers to the position of the stopper head when it is stationary under the constant torque M, with the sealing zero position as the reference value. If the stopper moves downward, the actual sealing position decreases, and vice versa.

2. A continuous casting machine, comprising a ladle, an tundish, and a crystallizer, characterized in that: During the automatic pouring process, the method described in claim 1 is used to seal the water inlet of the middle package.

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