A method for eliminating the adhesion between the stopper rod head and the nozzle during the automatic pouring process

Abstract

The present application discloses a method for freeing a stopper rod from adhering to a nozzle during an automatic pouring process, comprising: upon receiving an automatic pouring command, alternating the speed setting value and the actual torque value of a servo motor in a forward and reverse direction with a period T, with the actual torque value being less than or equal to a torque limit value; a displacement sensor detecting the actual position value of the stopper rod and comparing it with a reference position value of the stopper rod; if the actual position value of the stopper rod is less than the reference position value, the stopper rod is determined to be in a bonding zone or a loosening zone; the servo motor continues to alternately load the actual torque value and the speed setting value in a forward and reverse direction with a period T; if the actual position value of the stopper rod is greater than or equal to the reference position value of the stopper rod, the stopper rod is determined to be in a freeing zone, the torque limit value is increased, and the speed setting value V is controlled by the automatic pouring control system, and the subsequent steps of automatic pouring are entered. The stopper rod of the present application vibrates at high frequencies in the bonding zone and the loosening zone, which allows molten steel to flow more easily through the gap formed at the beginning of pouring, thereby improving the success rate of automatic pouring.

Description

Technical Field

[0001] The invention relates to a method for getting rid of adhesion between a stopper rod head and a nozzle in an automatic pouring process, belonging to the technical field of steelmaking continuous casting process in the metallurgical industry. Background Art

[0002] In continuous casting production, automatic pouring technology is increasingly being used to organize production. However, due to the stringent pre-conditions required for current automatic pouring technology, automatic pouring failure may easily occur due to some incidental factors. For example, the stopper rod head may be stuck to the nozzle and cannot be moved, causing nozzle blockage. The molten steel cannot enter the crystallizer through the nozzle, resulting in automatic pouring failure.

[0003] At present, most of the automatic pouring solutions, when receiving the automatic pouring command, under normal circumstances, the servo motor of the stopper rod runs in the forward direction, driving the stopper rod to rise, and at the same time the stopper rod head separates from the nozzle to form a gap, so that the molten steel can flow into the crystallizer through this gap. Figure 1 As shown by the dotted line in the figure, molten steel enters the mold through this gap, completing the subsequent automatic pouring process. If the stopper tip becomes stuck during pouring, and the sticking is severe, exceeding the stopper servo motor's ability to forcibly release it, the automatic pouring process is terminated and manual intervention is required to release the sticking. If the stopper tip is weakly stuck, the stopper servo motor can forcibly release it, completing the automatic pouring process. If left uncontrolled, this forced release can be powerful and can easily damage the high-temperature protective layer at the bond, shortening the stopper's service life. Damaged areas are also prone to nodules, making mold level control difficult. Furthermore, sticking is accidental and cannot be avoided or detected in advance. To avoid this uncertainty, some steel mills prefer to forgo automatic pouring to ensure subsequent stable production. Summary of the Invention

[0004] The present invention addresses the problems of the prior art and utilizes a high-frequency, low-speed, torque-limited vibration method to eliminate adhesion during the automatic pouring process, thereby avoiding damage to the stopper rod tip and improving the success rate of automatic pouring. The technical solution adopted is as follows:

[0005] A method for eliminating adhesion between a stopper rod head and a nozzle during an automatic pouring process, comprising the following steps:

[0006] After receiving the automatic pouring start instruction, the stopper rod servo motor is controlled to run at a speed setting value that alternates forward and reverse in a period T, and the torque limit value is set so that if adhesion occurs, the actual torque value of the stopper rod servo motor also runs in a forward and reverse alternating manner in the same period T, and the actual torque value is less than or equal to the torque limit value, and the forward speed corresponds to an increase in the stopper rod position value, and the reverse speed corresponds to a decrease in the stopper rod position value;

[0007] The actual position value of the stopper rod is detected and compared with the stopper rod reference position value. If the actual position value of the stopper rod is less than the stopper rod reference position value, it is determined that the stopper rod is in the bonding area or the loose area, and the servo motor continues to execute the positive and negative loading of the speed setting value and the actual torque value in a period T. If the actual position value of the stopper rod is greater than or equal to the stopper rod reference position value, it is determined that the stopper rod is in the escape area, the torque limit value is increased, and the speed setting value is controlled by the automatic pouring control system to enter the subsequent steps of automatic pouring.

[0008] Optionally, the forward speed setting is twice the reverse speed setting.

[0009] Optionally, in the bonding area and the loosening area, the torque limit value is 30% of the torque rating.

[0010] Optionally, in the bonding and loosening zones, the speed setting value is 5% of the rated speed value.

[0011] Optionally, increasing the torque limit value refers to increasing the torque limit value to the rated torque value.

[0012] The beneficial effects of the present invention are:

[0013] (1) Regardless of whether there is a bonding condition or not, the high-frequency vibration of the stopper rod in the bonding area and the loose area can make it easier for the molten steel to flow through the gap formed at the beginning of pouring, thereby improving the success rate of automatic pouring;

[0014] (2) In the bonding area and loose area, the torque is limited to a smaller torque to avoid damage to the high-temperature protective layer at the bonding area and not affect subsequent normal production;

[0015] (3) In the bonding and loosening zones, the asymmetric speed settings for both the forward and reverse directions unify the bonding and non-bonding production conditions, reducing control difficulty. In the non-bonding condition, the formation of small gaps in the initial pouring phase is not affected; in the bonding condition, the control system naturally generates a periodically alternating loosening torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of bonding the stopper rod head to the nozzle according to an embodiment of the present invention;

[0017] Figure 2 1 is a schematic diagram of a curve showing the relationship between the actual torque value, speed setting value, position value and time of the stopper rod according to an embodiment of the present invention.

[0018] Markings in the figure: 1-stopper rod, 2-sprue, 3-adhesive. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] like Figure 1 In the process of automatic pouring, the adhesive 3 adheres the stopper rod 1 to the nozzle 2, causing the nozzle to be blocked. The stopper rod servo motor drives the stopper rod to move vertically through the stopper rod actuator. The method of relieving the adhesion between the stopper rod head and the nozzle during the automatic pouring process of this embodiment is used to separate the stopper rod 1 from the nozzle 2, including the following steps:

[0021] Step S1: Upon receiving an automatic pouring start command, the torque limit of the servo motor is set to a relatively low torque, such as 30% of the rated torque. The speed of the servo motor is set to a relatively low speed setting value V, such as 5% of the rated speed. The stopper rod servo motor is controlled to operate at a speed setting value that alternates between forward and reverse directions with a period T. If sticking of the stopper rod occurs, the actual torque value of the servo motor also alternates between forward and reverse directions with the same period T, and the actual torque value is less than or equal to the torque limit. Preferably, the forward speed setting value is twice the reverse speed setting value. The forward speed causes the stopper rod position value to increase, i.e., move the stopper rod away from the nozzle, and the reverse speed causes the stopper rod position value to decrease, i.e., move the stopper rod closer to the nozzle.

[0022] For example Figure 2 In the example, the servo motor's forward speed is 2V, and its reverse speed is -V, alternating between forward and reverse speeds. If adhesion occurs while the forward speed is 2V, the actual torque value is Tq. While the reverse speed is -V, the actual torque value is -Tq.

[0023] In step S2, the displacement sensor detects the actual stopper position value ActPos and compares it with the stopper reference position value Pos. If the stopper actual position value ActPos is less than the Pos value, the stopper is defined as being in the bonding or loosening zone, and the servo motor continues to apply the actual torque value and speed setting at a period T. If the stopper actual position value ActPos is greater than or equal to the stopper reference position value Pos, the stopper is defined as being in the breakaway zone. In the breakaway zone, the torque limit is set to 100% of the rated torque value, and the automatic pouring control system controls the servo motor's speed setting value V, which then initiates normal automatic pouring. The stopper reference position value Pos may be a previously measured position obtained when the stopper is not bonded to the nozzle.

[0024] Specifically, if no sticking occurs, the stopper is in the loosening zone. Because the servo motor's forward speed is twice its reverse speed, the gap between the stopper tip and the nozzle gradually increases. ActPos will quickly exceed Pos, entering the breakaway zone and proceeding to the normal automatic pouring step. If sticking occurs, the speed setting value alternates between forward and reverse directions with a period of T. Due to the sticking of the stopper tip, the stopper's actual speed, ActSpd, is zero. When the speed setting is in the forward direction, the actual torque value is Tq; otherwise, it is -Tq, automatically alternating with the speed setting. This alternating torque easily creates a tiny gap between the stopper tip and the nozzle, forcing the hot molten steel to pass through this tiny gap and gradually melt the adhesive. As the adhesive melts, the bond begins to loosen, and as the gap gradually increases, the process proceeds to the normal automatic pouring step. If the sticking is severe, the stopper servo motor maintains a continuously low torque limit, allowing the alternating torque value to continue for a long time until the adhesive melts. If the sticking state cannot be eliminated, wait for manual treatment to terminate the automatic pouring process. Due to the relatively low torque limit value, there is no need to worry about damaging the high-temperature protective layer due to breaking the sticking. After manual treatment, the crystallizer liquid level control system can be safely put into use without affecting subsequent normal production.

[0025] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications shall fall within the scope of protection of the claims of the present invention.

Claims

1. A method for eliminating the adhesion between the stopper rod head and the nozzle during the automatic pouring process, characterized in that: The following steps are involved: After receiving the automatic pouring start instruction, the stopper rod servo motor is controlled to run at a speed setting value that alternates forward and reverse in a period T, and the torque limit value is set so that if adhesion occurs, the actual torque value of the stopper rod servo motor also runs in a forward and reverse alternating manner in the same period T, and the actual torque value is less than or equal to the torque limit value, and the forward speed corresponds to an increase in the stopper rod position value, and the reverse speed corresponds to a decrease in the stopper rod position value; The actual position value of the stopper rod is detected and compared with the stopper rod reference position value. If the actual position value of the stopper rod is less than the stopper rod reference position value, it is determined that the stopper rod is in the bonding area or the loose area, and the servo motor continues to execute the positive and negative loading of the speed setting value and the actual torque value in a period T. If the actual position value of the stopper rod is greater than or equal to the stopper rod reference position value, it is determined that the stopper rod is in the escape area, the torque limit value is increased, and the speed setting value is controlled by the automatic pouring control system to enter the subsequent steps of automatic pouring.

2. The method for eliminating adhesion between the stopper rod head and the nozzle during automatic pouring according to claim 1, characterized in that: The forward speed setting is twice the reverse speed setting.

3. The method for eliminating adhesion between the stopper rod head and the nozzle during automatic pouring according to claim 1, characterized in that: In the bonding area and loose area, the torque limit value is 30% of the torque rating.

4. The method for eliminating adhesion between the stopper rod head and the nozzle during automatic pouring according to claim 1, characterized in that: In the bonding area and loosening area, the speed setting value is 5% of the rated speed value.

5. The method for eliminating adhesion between the stopper rod head and the nozzle during automatic pouring according to claim 1, characterized in that: Increasing the torque limit value refers to increasing the torque limit value to the rated torque value.

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