Round billet vertical semi-continuous casting method and device

Abstract

The invention relates to the technical field of metallurgy, and provides a round billet vertical semi-continuous casting method and device.The method comprises the steps that after dummy ingot sealing operation is conducted on a crystallizer, argon with the preset volume is conveyed into the crystallizer; the crystallizer is sealed; molten steel is injected into the crystallizer to a preset liquid level; and high-pressure argon carrying casting powder particles is uniformly sprayed to the liquid level of the crystallizer. Argon is injected into the crystallizer after the dummy ingot sealing operation of the crystallizer, so that a stable argon protection layer is formed in the crystallizer, then the crystallizer is sealed, argon loss is avoided, molten steel is injected into the crystallizer, the argon protection layer can effectively isolate oxygen and water vapor in the air, the contact time of the molten steel with the air and the water vapor is shortened, and the molten steel is prevented from being damaged. The molten steel is effectively prevented from being oxidized, so that the vertical semi-continuous casting pouring quality of the super-large-section round billet is improved.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical technology, and more particularly, to a method and device for vertical semi-continuous casting of round billets. Background Art

[0002] With the rapid development of the metallurgical industry, the vertical semi-continuous casting technology of extra-large cross-section round billets has become one of the important processes for manufacturing special steel, and is widely used in the fields of heavy machinery, energy equipment, and aerospace. Compared with the traditional continuous casting process, the extra-large cross-section round billet has significant advantages such as reducing the number of hot working passes, improving material utilization rate, and reducing production costs. However, the production process of extra-large cross-section round billets also faces a series of technical challenges. Especially in the starting pouring stage, the extremely large increase in the cross-sectional size of the round billet poses higher requirements for the molten steel flow, liquid level stability, and purity.

[0003] Extra-large cross-section round billets generally refer to billets with a diameter of more than 1300 mm, and their cross-sectional area is several times that of conventional round billets. Due to the large cross-sectional area, the filling time required for the mold during starting pouring increases significantly, and the molten steel needs to be exposed to the air for a long time. In addition, during the starting pouring process, the molten steel rapidly fills the mold from top to bottom due to the action of gravity, forming a violent tumbling turbulent flow. It is difficult for the liquid level in the mold to quickly stabilize during the starting pouring stage, resulting in a large amount of molten steel inhaling gas, reacting with oxygen and nitrogen in the air, generating inclusions and reducing the purity of the molten steel. This phenomenon not only affects the internal quality of the billet but also increases the difficulty of subsequent processing. Summary of the Invention

[0004] The problem solved by the present invention is how to improve the quality of vertical semi-continuous casting of extra-large cross-section round billets.

[0005] To solve the above problems, the present invention provides a

[0006] In a first aspect, the present invention provides a method for vertical semi-continuous casting of round billets, characterized by including, after the mold sealing and dummy bar feeding operation, delivering a preset volume of argon gas into the mold;

[0007] Sealing the mold;

[0008] Injecting molten steel into the mold to a preset liquid level;

[0009] Uniformly spraying high-pressure argon gas carrying protective slag particles onto the liquid level of the mold.

[0010] Optionally, the preset volume is 2 times or 3 times the internal space volume of the mold.

[0011] Optionally, the time interval between sealing the mold and injecting molten steel into the mold to a preset liquid level is less than 5 minutes.

[0012] In a second aspect, the present invention provides a vertical semi-continuous casting device for round billets, comprising:

[0013] An argon blowing device is used to transport argon gas into the mold;

[0014] A sealing cover is used to seal the mold;

[0015] A submerged nozzle is used to inject molten steel into the mold through the sealing cover;

[0016] An automatic slag adding system is used to uniformly spray argon gas carrying protective slag particles onto the liquid surface of the mold.

[0017] Optionally, a through hole is formed in the sealing cover, and the size of the through hole matches the size of the submerged nozzle.

[0018] Optionally, a sealing cover plate is arranged on the through hole, and the sealing cover plate is used to seal the through hole.

[0019] Optionally, the automatic slag adding system includes a conveying pipeline and a feeding bin. One end of the conveying pipeline is inserted into the mold, and the other end of the conveying pipeline is connected to the feeding bin. The feeding bin is used to store argon gas and protective slag particles.

[0020] Optionally, the feeding bin includes a protective slag bin, and the protective slag bin is used to store protective slag particles.

[0021] Optionally, the feeding bin includes a gas storage device, and the inert gas conveying device is used to store argon gas.

[0022] Optionally, the end of the submerged nozzle far from the mold is connected to the tundish.

[0023] The beneficial effects of the vertical semi-continuous casting method and device for round billets of the present invention are as follows: After the mold sealing and ingot guiding operation, argon gas is injected into it, so that a stable argon gas protection layer is formed inside the mold. Then, the mold is sealed to avoid argon gas loss. Then, molten steel is injected into the mold. The argon gas protection layer can effectively isolate oxygen and water vapor in the air, reduce the contact time between the molten steel and air and water vapor, effectively prevent the oxidation of the molten steel, and thus improve the casting quality of the vertical semi-continuous casting of super-large section round billets. Description of the Drawings

[0024] Figure 1 It is a schematic flow chart of the vertical semi-continuous casting method for round billets according to an embodiment of the present invention;

[0025] Figure 2 It is a schematic structural diagram of the vertical semi-continuous casting device for round billets according to an embodiment of the present invention.

[0026] Description of the reference numerals:

[0027] 1 - Mold; 2 - Argon blowing device; 3 - Sealing cover; 31 - Through hole; 32 - Sealing cover plate; 4 - Submerged nozzle; 5 - Automatic slag adding system; 51 - Conveying pipeline; 52 - Feeding bin; 521 - Mold powder bin; 522 - Gas storage device; 6 - Tundish. Detailed implementation mode

[0028] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0029] It should be understood that the steps described in the method embodiments of the present invention can be executed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this regard.

[0030] The term "including" and its variants used herein are open - ended, that is, "including but not limited to"; the term "based on" is "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiment". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependent relationships.

[0031] It should be noted that the modifications of "one" and "multiple" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise clearly stated in the context, it should be understood as "one or more".

[0032] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only for illustrative purposes and are not used to limit the scope of these messages or information.

[0033] In view of the problems existing in the above - mentioned related technologies, the embodiments of the present invention provide a method and device for vertical semi - continuous casting of round billets.

[0034] Such as Figure 1 And Figure 2As shown, a vertical semi-continuous casting method for round billets provided by an embodiment of the present invention includes

[0035] Step S1: After the ingot blank sealing operation in the mold 1, a preset volume of argon gas is conveyed into the mold 1.

[0036] Specifically, after the ingot blank sealing operation in the mold 1, an opening space formed by the mold 1 and the ingot head 7 as shown in Figure 2 is formed. Continuously conveying high-sag argon gas into the interior of this control space can form a local protective atmosphere barrier between the ingot head 7 and the air, effectively isolating oxygen and water vapor in the air. To ensure the formation of a complete atmosphere barrier, usually argon gas with a volume 2 to 3 times that of the interior volume of the mold 1 is input into the mold 1. For example, for a vertical semi-continuous casting round billet mold 1 with a diameter of 1600 mm, the space volume is approximately 0.8 m 3 , then the preset volume is 1.6 m 3 to 2.4 m 3 . During actual pouring, usually 2.4 m 3 of argon gas is blown in within 5 minutes to complete gas replacement.

[0037] Step S2: Seal the mold 1.

[0038] Specifically, after the argon pre-protection is completed, a sealed protective cover can be set above the mold 1, for example, to seal the mold 1, prevent air from invading, ensure the formation of a complete inert gas protection layer before the molten steel enters the mold 1, and thus effectively avoid the oxidation risk in the area above the liquid level of the mold 1.

[0039] Step S3: Inject molten steel into the mold 1 to a preset liquid level.

[0040] Specifically, start the pouring operation. When ensuring that the molten steel injection process is protected by argon gas throughout, inject molten steel to a preset liquid level into the mold 1. It should be noted that the interval time between Step S2 and Step S3 should be less than 5 minutes. If the interval time is too long, it may cause the leakage of the protective atmosphere or interference from the outside air, reducing the protection effect. An interval time within 5 minutes can better maintain the stability of the protective atmosphere, give full play to the role of the atmosphere protection cover, and ensure that the molten steel is cast under good protection conditions.

[0041] Step S4: Uniformly spray high-pressure argon gas carrying protective slag particles onto the liquid level of the mold 1 to effectively isolate air and prevent the oxidation of molten steel.

[0042] In this embodiment, after the ingot guiding operation in the mold 1, argon gas is injected into it to form a stable argon gas protective layer inside the mold. Then, the mold 1 is sealed to prevent the loss of argon gas. Subsequently, molten steel is injected into the mold 1. The argon gas protective layer can effectively isolate oxygen and water vapor in the air, reduce the contact time between the molten steel and air and water vapor, effectively prevent the oxidation of the molten steel, and thus improve the casting quality of the vertical semi-continuous casting of ultra-large cross-section round billets.

[0043] As Figure 2 shown, another embodiment of the present invention discloses a vertical semi-continuous casting device for round billets, including:

[0044] The argon blowing device 2 is used to convey argon gas into the mold 1;

[0045] The sealing cover 3 is used to seal the mold 1;

[0046] The submerged nozzle 4 is used to inject molten steel into the mold 1 through the sealing cover 3;

[0047] The automatic slag adding system 5 is used to uniformly spray argon gas carrying protective slag particles onto the liquid surface of the mold 1.

[0048] Specifically, as Figure 2 shown in (a), the argon blowing device 2 includes a storage device and a conveying pipeline. The storage device is used to store argon gas and convey it into the mold 1 through the conveying pipeline connected to the inside of the mold 1. As Figure 2 shown in (b), the shape of the sealing cover 3 matches the shape of the top of the mold 1, and the diameter of the sealing cover 3 is slightly larger than the diameter of the sealed device. A sealing strip is provided on the outer diameter of the sealing cover 3 to increase the sealing effect when the sealing cover 3 covers the mold 1. As Figure 2 shown in (c), the tundish 6 can be moved to the casting position of the mold 1 by the tundish car, keeping the opening at the top of the submerged nozzle 4 aligned with the protective cover. One end of the submerged nozzle 4 is connected to the tundish 6, and the other end passes through the sealing cover 3 and is placed inside the mold 1 to inject molten steel into the mold 1 for casting, ensuring that the molten steel is covered by the protective atmosphere of argon gas throughout the injection process. Figure 2 shown in (d), after the molten steel is injected to the preset position, the submerged nozzle 4 and the sealing cover 3 are removed, and the automatic slag adding system 5 is moved to the corresponding position and uniformly and quickly sprayed onto the liquid surface of the mold 1, further reducing the contact area and time between the molten steel and air, increasing the casting quality. At the same time, it can adjust the slag adding amount and slag adding frequency in real time according to parameters such as the liquid level and temperature of the molten steel, maintain the stability of the protective slag layer in the mold 1, avoid production fluctuations caused by uneven or untimely manual slag adding, and improve the stability and continuity of production.

[0049] Optionally, a through hole 31 is provided on the sealing cover 3, and the size of the through hole 31 matches the size of the submerged nozzle 4.

[0050] Specifically, during the starting pouring process, the molten steel rapidly fills the mold 1 from top to bottom due to gravity, forming a violent tumbling turbulent flow, which causes a large amount of air to be sucked into the molten steel. The air flow inside the mold 1 becomes larger. In order to ensure that the argon gas inside the mold 1 does not escape when the submerged nozzle 4 injects molten steel into the mold 1, a through hole 31 matching the size of the submerged nozzle 4 is opened on the sealing cover 3. The diameter of the through hole 31 matches the cross-sectional diameter of the submerged nozzle 4. The submerged nozzle 4 is inserted into the mold 1 through the through hole 31 to achieve the sealing effect during the injection of molten steel.

[0051] Furthermore, a sealing strip can also be provided on the through hole 31 to further enhance the sealing effect.

[0052] Optionally, a sealing cover plate 32 is provided on the through hole 31, and the sealing cover plate 32 is used to seal the through hole 31.

[0053] Specifically, when the submerged nozzle 4 is not inserted, the sealing cover plate 32 seals the through hole 31 to prevent air from invading. When it is necessary to insert the submerged nozzle 4, the sealing cover plate 32 can be lifted.

[0054] Optionally, the automatic slag adding system 5 includes a conveying pipeline 51 and a feeding bin. One end of the conveying pipeline 51 is inserted into the mold 1, and the other end of the conveying pipeline 51 is connected to the feeding bin. The feeding bin is used to store argon gas and protective slag particles.

[0055] Optionally, the feeding bin includes a protective slag bin 52, and the protective slag bin 52 is used to store protective slag particles.

[0056] Optionally, the feeding bin includes a gas storage device 53, and the inert gas conveying device is used to store argon gas.

[0057] Specifically, when installing the automatic slag adding system 5, the sealing cover 3 should be removed first to provide space for the automatic slag adding system 5 to enter the working position. The automatic slag adding system 5 uses the principle of pneumatic conveying to retrieve high-pressure argon gas from the gas storage device 53 and retrieve protective slag particles from the protective slag bin 52. The high-pressure argon gas carries the protective slag particles and uniformly sprays them onto the liquid surface in the mold 1 from the slag adding nozzle, so that the protective slag particles can quickly and uniformly cover the surface of the molten steel. At the same time, the high-pressure argon gas can also reduce the contact area and time between the molten steel and air, providing a buffer time for the protective slag particles to cover, so as to improve the quality of the molten steel.

[0058] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A method for vertical semi-continuous casting of round billets, characterized in that, including After the mold sealing operation, delivering a preset volume of argon gas into the mold; Sealing the mold; Injecting molten steel into the mold to a preset liquid level; Uniformly spraying high-pressure argon gas carrying protective slag particles onto the liquid surface of the mold.

2. The vertical semi-continuous casting method for round billets according to claim 1, characterized in that, The preset volume is 2 or 3 times the internal space volume of the mold.

3. The vertical semi-continuous casting method for round billets according to claim 1, characterized in that, The time interval between sealing the mold and injecting molten steel into the mold to a preset liquid level is less than 5 minutes.

4. A vertical semi-continuous casting device for round billets, characterized in that, including: An argon blowing device (2) for delivering argon gas into the mold (1); A sealing cover (3) for sealing the mold (1); A submerged nozzle (4) for injecting molten steel into the mold (1) through the sealing cover (3); An automatic slag adding system (5) for uniformly spraying argon gas carrying protective slag particles onto the liquid surface of the mold (1).

5. The round billet vertical semi-continuous casting device according to claim 4, characterized in that, A through hole (31) is formed on the sealing cover (3), and the size of the through hole (31) matches the size of the submerged nozzle (4).

6. The round billet vertical semi - continuous casting device according to claim 5, characterized in that, A sealing cover plate (32) is arranged on the through hole (31), and the sealing cover plate (32) is used for sealing the through hole (31).

7. The round billet vertical semi-continuous casting device according to claim 4, characterized in that, The automatic slag adding system (5) includes a conveying pipeline (51) and a feeding bin. One end of the conveying pipeline (51) is inserted into the mold (1), and the other end of the conveying pipeline (51) is connected to the feeding bin. The feeding bin is used for storing argon gas and protective slag particles.

8. The round billet vertical semi-continuous casting device according to claim 7, characterized in that, The feeding bin includes a protective slag bin (52) for storing protective slag particles.

9. The round billet vertical semi - continuous casting device according to claim 7, characterized in that, The feeding bin includes a gas storage device (53) for storing argon gas. The inert gas conveying device is used for storing argon gas.

10. The round billet vertical semi-continuous casting device according to claim 4, characterized in that, The end of the submerged nozzle (4) far from the mold (1) is connected to the tundish (6).

Images