A casting device composed of a stopper for continuous casting and a matched integral submerged entry nozzle

Abstract

This invention belongs to the field of continuous casting technology, specifically relating to a stopper rod for continuous casting and a matching integral submerged entry nozzle. When using argon blowing with the stopper rod and the bowl-shaped nozzle to remove nodules from the rod head, subsurface defects in the cast billet are easily caused. To address this problem, this invention provides a stopper rod for continuous casting and a matching integral submerged entry nozzle, including a stopper rod and an integral submerged entry nozzle. The integral submerged entry nozzle has a high-hardness annular protrusion on the inner wall of the bowl-shaped nozzle. When nodules form on the surface of the rod head and gradually block the minimum gap between the bowl-shaped nozzle and the rod head, the rod head rotates within the bowl-shaped nozzle and moves up and down axially. The annular protrusion on the inner wall of the bowl-shaped nozzle can then be used to scrape away the nodules on the surface of the rod head. The scraped-off nodules enter the upper part of the crystallizer through outlets at the bottom of the first and second cavities, which are higher than the cover plate, and slowly float upwards. They are easily captured by the protective slag in the crystallizer, minimizing the impact on the molten steel surface and thus reducing the likelihood of subsurface defects in the cast billet.

Description

Technical Field

[0001] This invention belongs to the field of continuous steel casting technology, specifically relating to a casting device consisting of a stopper rod for continuous casting and a matching integral submersible nozzle. Background Technology

[0002] In the continuous casting area of ​​a steel plant, stopper rods and integral submerged nozzles are used to control the flow of molten steel and connect the tundish and the crystallizer. They are widely used due to their advantages of simple flow control with stopper rods, large throughput with integral nozzles, and good sealing, especially for casting pipeline steel and silicon deoxidized steel. However, when casting aluminum deoxidized steel such as bearing steel, inclusions in the molten steel easily accumulate at the head of the stopper rod, forming nodules (nodules are magnesium aluminum spinel or a small amount of high-melting-point calcium aluminate). The formation of nodules on the rod head surface causes the stopper rod position curve to rise, leading to the stopper rod mechanism reaching its maximum stroke of 12mm, rendering the stopper rod's flow control function ineffective. If the nodules on the rod head surface detach, they can easily fall into the molten steel in the crystallizer, causing fluctuations in the molten steel level and introducing large inclusions into the billet, resulting in excessive inclusions in the steel and even subcutaneous defects in the billet. This reduces the steel's fatigue life and impact resistance.

[0003] To remove nodules formed on the surface of the stopper rod, methods such as argon blowing with the stopper rod, argon blowing through a bowl, or large-flow steel flushing are commonly used. However, these methods have the following drawbacks: the argon flow rate of stopper rod and bowl blowing is difficult to control. When the flow rate is high, the liquid surface in the crystallizer churns, which can easily lead to subcutaneous defects in the cast billet; when the flow rate is low, the removal effect of nodules is not obvious. Large-flow steel flushing can only maintain pouring for a short period of time. Repeated large-flow steel flushing will cause the stopper rod to rise. When the stopper rod reaches its upper limit, it cannot flush again, ultimately causing a stop for one flow / the entire pouring cycle and forcing a production interruption. Summary of the Invention

[0004] A problem with existing technologies is that when using argon blowing with a stopper rod or a bowl-shaped argon blowing method to remove nodules from the stopper rod head, subsurface defects can easily appear on the cast billet. To address this problem, this invention provides a casting apparatus consisting of a stopper rod for continuous casting and a matching integral submersible nozzle, including a stopper rod and an integral submersible nozzle. The stopper rod includes a rod body and a rod head. The rod head and the adjacent end face of the rod body are in contact with each other. The axial length of the rod head is 1 / 10 to 1 / 12 of the axial length of the rod body, and the axial length of the rod head is 100-105 mm. The rod head is tapered; the rod body is cylindrical with an axial diameter of φ110-φ120mm.

[0005] The integral submersible nozzle includes an integral submersible nozzle body, an open bowl-shaped upper end, a cavity in the middle, and a closed cover plate at the lower end. A diversion dam is provided within the cavity. The upper end of the diversion dam is located below the nozzle head and does not contact it. The lower end face of the diversion dam is fixedly mounted on the inner surface of the cover plate. The diversion dam divides the cavity into two isolated cavities below its upper end, forming a first cavity and a second cavity. Liquid in both cavities cannot pass through the portion below the upper end of the diversion dam. The first cavity and its lower portion have discharge holes on the surface of the integral submersible nozzle body. The inner wall of the bowl is formed into a conical surface circumferentially. The taper of the inner wall of the bowl is the same as the taper of the rod head. When 1 / 3 of the axial length of the rod head extends into the bowl, the perpendicular distance between the two closest tangents of the outer wall of the rod head and the inner wall of the bowl is 2-4 mm. The axes of the first and second discharge holes are parallel to the ground and located 15-30mm above the cover plate; Starting from a position 0.1-0.2mm below the upper surface of the bowl, an annular protrusion is provided circumferentially on the conical surface of its inner sidewall, and the height of the annular protrusion is 1-1.5mm. The Mohs hardness of the annular protrusion is not less than 6, and the axial displacement generated by rotating one revolution along the annular protrusion is not greater than 2mm.

[0006] Preferably, the annular protrusion is made of zirconium mullite.

[0007] Preferably, the diversion dam divides the cavity into two equal parts along its upper end to obtain a first cavity and a second cavity.

[0008] Preferably, the rod head has several annular steps on its axial conical surface, the adjacent end faces of adjacent annular steps are in contact with each other, and each annular step is coaxial and has the same taper.

[0009] Preferably, the cross-sectional shape of the annular protrusion is triangular.

[0010] Preferably, the first cavity and the lower discharge holes of the second cavity are arranged symmetrically along the radial direction and are exactly the same size.

[0011] Preferably, the upper end of the diversion dam has a triangular cross-sectional shape.

[0012] Preferably, the taper of the rod head is 1.10-1.14.

[0013] Preferably, the rod body and the rod head are integrally formed.

[0014] The present invention has the following beneficial effects: This invention features a high-hardness annular protrusion on the inner circumference of the bowl-shaped nozzle. When nodules form on the surface of the rod head and gradually block the minimum gap between the bowl and the rod head, the rod head rotates within the bowl and moves 2mm up and down axially. The annular protrusion on the inner wall of the bowl can then be used to scrape away the nodules on the surface of the rod head. The scraped nodules fall along the first and second cavities and enter the upper part of the crystallizer through the outlets at the bottom of the first and second cavities, which are higher than the cover plate. They then slowly float upwards and are easily captured by the protective slag in the crystallizer. This prevents large fluctuations in the molten steel surface within the crystallizer, thus reducing the likelihood of subcutaneous defects in the cast billet. Attached Figure Description

[0015] Figure 1 This is an axial cross-sectional schematic diagram of a continuous casting stopper rod and its matching integral submersible nozzle in use according to the present invention.

[0016] Figure 2 This is a top view of a matching integral immersion sprue of the present invention.

[0017] In the diagram, 1-1. Rod body, 1-2. Rod head, 1-3. Annular step, 2-1. Bowl mouth, 2-2. Second cavity, 2-3. Second outlet, 2-4. Cover plate, 2-5. First outlet, 2-6. Annular boss, 2-7. First cavity, 3. Water diversion dam. Detailed Implementation

[0018] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.

[0019] like Figure 1-2 The image shows a casting apparatus according to the present invention, consisting of a stopper rod for continuous casting and a matching integral submersible nozzle, including a stopper rod and an integral submersible nozzle. The stopper rod includes a rod body 1-1 and a rod head 1-2. The rod head 1-2 is in contact with the adjacent end face of the rod body 1-1. The axial length of the rod head 1-2 is 1 / 10 to 1 / 12 of the axial length of the rod body 1-1, and the axial length of the rod head 1-2 is 100-105mm. The rod head 1-2 has a taper; the rod body 1-1 is a cylinder with an axial diameter of φ110-φ120mm.

[0020] The integral submersible nozzle includes an integral submersible nozzle body 2-2, an open bowl-shaped opening 2-1 at the upper end, a cavity in the middle, and a closed cover plate 2-4 at the lower end. A diversion dam 3 is provided within the cavity. The upper end of the diversion dam 3 is located below the rod head 1-2 and the two are not in contact. The lower end face of the diversion dam 3 is fixedly mounted on the inner surface of the cover plate 2-4. The diversion dam 3 divides the cavity into two isolated cavities, a first cavity 2-7 and a second cavity 2-8, along its lower portion. Liquid in both cavities cannot pass through the portion below the upper end of the diversion dam 3. A first discharge hole 2-5 and a second discharge hole 2-3 are respectively provided on the surface of the integral submersible nozzle body 2-2 at the lower part of the first cavity 2-7 and the second cavity 2-8. The inner wall of the bowl 2-1 forms a conical surface circumferentially. The taper of the inner wall of the bowl 2-1 is the same as the taper of the rod head 1-2. When 1 / 3 of the axial length of the rod head 1-2 extends into the bowl 2-1, the perpendicular distance between the two closest tangents between the outer wall of the rod head 1-2 and the inner wall of the bowl 2-1 is 2-4 mm. The axes of the first discharge hole 2-5 and the second discharge hole 2-3 are parallel to the ground and located 15-30mm above the cover plate 2-4; The bowl 2-1 has an annular protrusion 2-6 circumferentially arranged on its inner side conical surface, starting from a position 0.1-0.2mm below its upper surface. The height of the annular protrusion 2-6 is 1-1.5mm. The Mohs hardness of the annular protrusion 2-6 is not less than 6, and the axial displacement generated by rotating one revolution along the annular protrusion 2-6 is not greater than 2mm.

[0021] In order to better remove nodules from the surface of the rod head 1-2, the annular protrusions 2-6 are made of zircon mullite.

[0022] In order to better ensure that the molten steel and nodules flow out of the discharge hole in a designated direction and to avoid the nodules not being captured by the protective slag due to an uneven flow field of molten steel in the crystallizer, the diversion dam 3 divides the cavity into two equal parts along its upper end to obtain the first cavity 2-7 and the second cavity 2-8.

[0023] In order to maximize the flow rate of molten steel per unit time and per unit cross-sectional area of ​​the stopper rod, the rod head 1-2 is provided with several annular steps 1-3 along its axial conical surface. The adjacent end faces of adjacent annular steps 1-3 fit together, and each annular step 1-3 is coaxial and has the same taper.

[0024] In order to better remove the nodules on the surface of the rod head 1-2, the cross-sectional shape of the annular protrusion 2-6 is triangular.

[0025] To ensure that the molten steel flow field and steel throughput are the same on both sides, so that the nodules can flow smoothly into the crystallizer, float slowly, and be captured by the protective slag, the discharge holes at the bottom of the first cavity 2-7 and the second cavity 2-8 are arranged radially symmetrically and are exactly the same size.

[0026] To better prevent turbulent vortices from forming during the flow of molten steel through the cavity and affecting the flow field of molten steel inside the crystallizer, the upper end of the diversion dam 3 has a triangular cross-sectional shape.

[0027] In order to achieve a better steel flow guiding effect in conjunction with the bowl 2-1, the taper of the rod head 1-2 is 1.10-1.14.

[0028] To simplify the manufacturing process of the stopper rod, the rod body 1-1 and the rod head 1-2 are integrally formed.

[0029] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A casting apparatus consisting of a stopper rod for continuous casting and a matching integral submersible nozzle, characterized in that, Including stopper rods and integral submersible nozzles, The stopper rod includes a rod body (1-1) and a rod head (1-2). The rod head (1-2) is in contact with the adjacent end face of the rod body (1-1). The axial length of the rod head (1-2) is 1 / 10 to 1 / 12 of the axial length of the rod body (1-1), and the axial length of the rod head (1-2) is 100-105 mm. The rod head (1-2) has a taper; The integral submersible nozzle includes an integral submersible nozzle body (2-2), an open bowl-shaped opening at the upper end (2-1), a cavity in the middle, and a closed cover plate (2-4) at the lower end. A diversion dam (3) is provided in the cavity. The upper end of the diversion dam (3) is located below the rod head (1-2) and the two do not contact each other. The lower end face of the diversion dam (3) is fixedly set on the inner surface of the cover plate (2-4). The diversion dam (3) divides the cavity into two isolated cavities, a first cavity (2-7) and a second cavity (2-8), along the part below its upper end. Liquid in both cavities cannot pass through the part below the upper end of the diversion dam (3). The lower part of the first cavity (2-7) and the second cavity (2-8) are respectively provided with a first discharge hole (2-5) and a second discharge hole (2-3) on the surface of the integral submersible nozzle body (2-2). The inner wall of the bowl (2-1) forms a conical surface circumferentially. The taper of the inner wall of the bowl (2-1) is the same as the taper of the rod head (1-2). When 1 / 3 of the axial length of the rod head (1-2) extends into the bowl (2-1), the perpendicular distance between the two closest tangents between the outer wall of the rod head (1-2) and the inner wall of the bowl (2-1) is 2-4 mm. The axes of the first discharge hole (2-5) and the second discharge hole (2-3) are parallel to the ground and located 15-30mm above the cover plate (2-4); The bowl (2-1) has an annular protrusion (2-6) circumferentially arranged on the conical surface of its inner sidewall, starting from a position 0.1-0.2mm below its upper surface. The height of the annular protrusion (2-6) is 1-1.5mm. The Mohs hardness of the annular protrusion (2-6) is not less than 6, and the axial displacement generated by rotating one revolution along the annular protrusion (2-6) is not greater than 2mm.

2. The casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle as described in claim 1, characterized in that, The annular protrusions (2-6) are made of zircon mullite.

3. The casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle as described in claim 1, characterized in that, The diversion dam (3) divides the cavity into two equal parts along its upper end to obtain the first cavity (2-7) and the second cavity (2-8).

4. The casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle as described in claim 1, characterized in that, The rod head (1-2) has an annular step (1-3) on its axial conical surface. The adjacent end faces of adjacent annular steps (1-3) fit together, and each annular step (1-3) is coaxial and has the same taper.

5. A casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle, as described in claim 1, characterized in that... The cross-sectional shape of the annular protrusion (2-6) is triangular.

6. The casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle according to claim 1, characterized in that, The lower discharge holes of the first cavity (2-7) and the second cavity (2-8) are arranged symmetrically along the radial direction and are exactly the same size.

7. A casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle, as described in claim 1, is characterized in that... The cross-sectional shape of the upper end of the diversion dam (3) is triangular.

8. A casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle, as described in claim 1, is characterized in that... The taper of the rod head (1-2) is 1.10-1.

14.

9. A casting apparatus comprising a stopper rod for continuous casting and a matching integral submersible nozzle, as described in claim 1, is characterized in that... The rod body (1-1) and the rod head (1-2) are integrally formed.

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