Method for continuously casting strand

Abstract

The invention relates to a method for continuously casting a strand, in particular for continuously casting a strand. In order to enable reproducible high-quality continuous casting, it is proposed that the manipulator (8) moves the closing plug (7) in at least one further degree of freedom (x, y, [phi] x, [phi] y, [phi] z), which differs from the first degree of freedom (z), when the metal melt (3) flows from the ladle (2) through the immersion tube into the liquid bath (6) of the crystallizer (4), in particular when the strand is pulled out, and that the closing plug (7) is moved by the manipulator (8) in at least one further degree of freedom (x, y, [phi] x, [phi] y, [phi] z), which differs from the first degree of freedom (z), the flow field (ux, y, z, t) is moved, in particular along a second movement trajectory (11), and thereby acts hydrodynamically on the metal melt (3) in order to change the formed flow field (ux, y, z, t).

Description

Technical Field

[0001] The present invention relates to a method for continuously casting billets, particularly a method for continuously casting billets, wherein, particularly during the drawing of the billet, molten metal flows from a ladle with a closure plug, particularly from an tundish with a closure plug, through at least one immersion pipe into a liquid bath of a crystallizer, and wherein the volumetric flow rate of the molten metal through the immersion pipe is set and / or regulated by the closure plug by a manipulator connected to the closure plug moving the closure plug in a first degree of freedom, particularly along a first movement trajectory, thereby creating a flow field in the molten metal from the ladle to the crystallizer. Background Technology

[0002] As known in (EP0564674A1), the height of the liquid level (often also called the casting level) in the liquid bath of a continuous casting equipment's crystallizer is set by means of a sealing plug, which is coaxially moved to the inlet of an immersion filler pipe that flows into the crystallizer. The sealing plug is moved along a first linear trajectory using a manipulator, which moves the sealing plug vertically along the first trajectory in a first degree of freedom z.

[0003] For relatively high-quality continuous casting, a symmetrical flow field needs to be formed in the liquid bath, which is also reflected in the surface undulation of the liquid level in the crystallizer's liquid bath. For example, scaling at the distributor (tundish), immersion pipe, and / or sealing plug can cause turbulence in the flow pattern, leading to increased surface undulation of the liquid level. To reduce surface undulation of the liquid level, WO95 / 30500A1 proposes moving floats back and forth in the liquid bath of the crystallizer, thereby influencing the molten metal in a hydrodynamic manner to change the flow field formed in the molten metal within the continuous casting equipment. However, this is relatively expensive structurally and requires intensive maintenance, mainly due to concerns about scaling and / or precipitation on the floats, which can affect continuous casting when they detach. Furthermore, operating or adjusting such floats is relatively complex. Similar measures are also known from WO00 / 02685A1. Summary of the Invention

[0004] Therefore, the objective of this invention is to create a method for achieving high-quality continuous casting in a reproducible manner. Furthermore, the method should be easy to operate.

[0005] The present invention achieves the proposed objective through the features of claim 1.

[0006] As molten metal flows from a ladle through an immersion pipe into the liquid bath of the crystallizer, the manipulator moves the closure plug in at least one additional degree of freedom, different from the first degree of freedom, and thereby acts on the molten metal in a hydrodynamic manner. This additional degree of freedom allows for alteration of the resulting flow field. For example, this can reproducibly provide relatively high-quality continuous casting and / or reproducibly ensure such continuous casting. For example, this can lead to a method for continuously casting billets with better reproducibility, particularly a method for continuously casting billets.

[0007] Furthermore, the relative ease of maneuvering the sealing plug in the other degree of freedom significantly simplifies the method. Unlike existing technologies, the relatively expensive additional tools used for hydrodynamic measures in the crystallizer can also be eliminated. The method according to the invention thus not only ensures high-quality continuous casting in a reproducible manner, but is also user-friendly in application and relatively easy to implement structurally.

[0008] Preferably, the manipulator makes this movement when the continuously cast billet is pulled out. It may be that during the continuous casting of the billet, the volumetric flow rate of the molten metal through the immersion filler tube is set and / or regulated by a closure plug, for example, thereby setting or regulating the tank level in the crystallizer to a target height.

[0009] This movement, in at least one additional degree of freedom, occurs, for example, along a second trajectory. The second trajectory differs from the first trajectory at least in some segments.

[0010] The manipulator can move the closure plug in a translational and / or rotational manner. For example, moving the closure plug in a translational manner in at least one translational degree of freedom (x and / or y) can react to the existing asymmetric flow field within the crystallizer. For example, it can move the closure plug in a rotational degree of freedom (x and / or y) to react to the existing asymmetric flow field within the crystallizer. and / or The sealing plug is moved by rotation to make the flow field inside the crystallizer more stable in the face of disturbance.

[0011] Because the sealing plug alters the flow field, it can act hydrodynamically on the molten metal, for example, during the sealing plug's movement, thus changing the flow field formed at least from the ladle to the crystallizer. This can affect a wide range of sections of the continuous casting equipment, thereby further improving reproducibility in producing high-quality continuous castings.

[0012] Preferably, the undulation of the liquid level surface of the liquid bath and / or the fluctuation of the liquid level in the liquid bath of the crystallizer can be reduced by utilizing the altered flow field within the crystallizer.

[0013] For example, reducing the waviness of the slag level surface can further improve the quality of continuous casting and the quality of the resulting slabs. This is achieved by improving the function of the slag layer above the slag level in the crystallizer. The slag floating at the slag level in the crystallizer can thus better absorb impurities rising from the molten metal and better protect the molten metal from the influence of the ambient atmosphere. The waviness of the slag level surface refers, for example, to the difference between the maximum and minimum heights of the slag level surface; more specifically, it is the difference in the vertical direction between the maximum and minimum heights of the slag level surface across the complete cross-section of the crystallizer at a given moment during the continuous casting process.

[0014] For example, by reducing fluctuations in the tank liquid level, the height difference of the initial continuous casting billet shell growth (meniskus) in the circumferential direction of the mold can be reduced, which facilitates more uniform solidification of the continuous casting billet within the cross-section. More uniform initial continuous casting billet shell growth can further reduce the risk of the initially very thin continuous casting billet shell warping or breaking within the mold.

[0015] Fluctuations in the tank level are, for example, the difference between the maximum and minimum heights, or more specifically, the difference between the maximum and minimum heights in the vertical direction at a point on the surface of the tank level during continuous casting.

[0016] Preferably, by utilizing a modified flow field within the crystallizer, two vortex regions rotating in opposite directions within the crystallizer's liquid bath are made symmetrical. This symmetry of the vortex regions can be achieved, for example, by moving the sealing plug from a central position relative to the immersion nozzle to an off-center position. Furthermore, the symmetrical vortex regions within the crystallizer's liquid bath may, for example, cause symmetrical growth of the continuously cast billet shell, which promotes uniformity of quality and material properties on the continuously cast billet. For example, this can thereby make the two vortex regions rotating in opposite directions within the crystallizer approximately mirror-symmetrical.

[0017] Preferably, a modified flow field is used to remove scale, for example, in an immersion injection tube. Alternatively, a modified flow field can also be used to prevent scale, for example, in an immersion injection tube.

[0018] Scaling can be removed, for example, by creating a turbulent flow pattern within the scaling region through a modified flow field. By avoiding or removing scaling, quality losses in continuous casting are also prevented, such as due to the fracturing of alumina scale within the adjustment gap (“unblocking”).

[0019] Additionally, the amount of molten metal remaining in the ladle can be reduced, for example, by altering the flow field. This remaining amount is known to be necessary for the trouble-free operation of continuous casting equipment. For instance, the existing flow field can be altered by the rotational movement of the sealing plug. This allows for more efficient continuous casting with lower remaining amounts.

[0020] Preferably, as the sealing plug moves in at least one additional degree of freedom, the volumetric flow rate of the molten metal through the immersion injection pipe is approximately the same, thereby ensuring a symmetrical flow field within the crystallizer when the tank level remains constant. This also allows the average tank level height within the crystallizer to remain constant. This eliminates the need to change the adjustment strategy for the average tank level, further simplifying the method.

[0021] To further improve the control over the hydrodynamic effects on the flow field in at least one additional degree of freedom, a device can be specified to have at least one sensor detect the profile of the surface of the tank liquid level, and the device can manipulate a manipulator to move a sealing plug. For example, this can allow for a relatively dynamic response to asymmetries in the flow field within the crystallizer. For instance, if the sensor detects asymmetric undulations in the tank liquid level within the crystallizer, this asymmetry can be rapidly compensated for by adjusting the movement of the sealing plug.

[0022] For altering the flow field created by the molten metal in the immersion injection tube and / or crystallizer, additional degrees of freedom such as translational or rotational degrees of freedom are sufficient.

[0023] Preferably, the manipulator moves the sealing plug in a plurality of, for example, at least two additional degrees of freedom, in a translational and / or rotational manner. This can further improve the feasibility of altering the flow, for example, in a static and / or dynamic sense. For example, periodic movement of the sealing plug can cause periodic changes in the flow field, which makes the flow field more stable in the face of disturbances and thereby further improves the homogenization of continuous casting.

[0024] Preferably, when the sealing plug is moved in at least one additional degree of freedom, purge gas is discharged from the sealing plug from at least one purge gas port (15) opened on the sealing plug, preferably eccentrically. The purge gas port is positioned on the sealing plug, for example, eccentrically.

[0025] By using a purge gas inlet, the purge gas can be introduced into the molten metal at a position that changes over time. This allows for more uniform mixing of the purge gas and the molten metal and further improves the method.

[0026] The above can be further improved if the manipulator rotates the sealing plug around the rotation axis as the purge gas is discharged from the sealing plug.

[0027] If the manipulator is constructed as a robotic arm, the operation of the method can be made easier. Preferably, the robotic arm, such as an articulated robotic arm, has six degrees of freedom (6DoF). Brief description of the attached diagram

[0028] The accompanying drawings illustrate the inventive subject matter in detail, for example, with the aid of several variant embodiments.

[0029] Figure 1 A partial diagram of a continuous casting apparatus with a manipulator for moving the sealing plug, according to the prior art, is shown.

[0030] Figure 2 It shows that according to Figure 1 A continuous casting apparatus having a manipulator for moving a sealing plug according to the invention.

[0031] Figure 3a , Figure 3b An example of a first method for reducing the surface undulation of the liquid level in a crystallizer is shown.

[0032] Figure 4a , Figure 4b An example of a second method for stabilizing periodic flows is shown.

[0033] Figure 5a , Figure 5b An example of a third method for avoiding and / or removing scale is shown, and

[0034] Figure 6a , Figure 6b An example of a fourth method for reducing the amount of residual molten metal 3 in the ladle 2 of a continuous casting equipment is shown. Detailed Implementation

[0035] according to Figure 1 The diagram shows a ladle 2 (intermediate ladle) containing molten metal 3 and a crystallizer 4 from continuous casting equipment 1. The crystallizer is flowably connected to the ladle 2 via an immersion pouring pipe 5. The molten metal 3 flows from the ladle 2 into the immersion pouring pipe 5 and then into the crystallizer 4 where the immersion pouring pipe leads to a liquid bath 6. The intermediate ladle is also often referred to as a distributor or intermediate ladle in continuous casting equipment. A partially solidified continuously cast billet (not shown in detail) emerges from the crystallizer 4 and is pulled out of the continuous casting equipment; this process is not shown in detail.

[0036] The ladle 2 is also equipped with a sealing plug 7, which is used to set the volumetric flow rate of the molten metal 3 flowing through the submerged injection pipe 5, more precisely, to set the volumetric flow rate when the continuously cast billet is pulled out. This setting is achieved by moving the sealing plug 7 in a translational manner in the first degree of freedom z by the manipulator 8. The movement trajectory 9 extends vertically for this purpose and moves the sealing plug 7 toward or away from the inlet 5a of the submerged injection pipe 5 as needed. By acting on the molten metal 3 in such a hydrodynamic manner, the locally average liquid level P in the crystallizer 4 is kept approximately constant. A flow field u is formed in the molten metal 3. x,y,z,t .

[0037] Generally speaking, the flow field u x,y,z,tIt is a vector field that assigns a velocity v(x,y,z) that varies with time t to each spatial point (x,y,z) in the flow.

[0038] According to the invention, the molten metal 3 is acted upon in a hydrodynamically expanding manner by means of a sealing plug 7. For example... Figure 2 As shown, the closing plug 7 is moved by the manipulator 8 in at least one additional degree of freedom, x, y, and / or This is achieved by moving along the second movement path 11. The additional degrees of freedom x, y, and / or Unlike the first degree of freedom z.

[0039] This movement occurs as the molten metal 3 flows from the ladle 2 into the liquid bath 6 of the crystallizer via the submerged injection pipe 5, thereby continuously casting the continuous casting billet. The flow 12 of the molten metal 3 flowing into the submerged injection pipe 5 is thus acted upon in a hydrodynamic manner, that is, the flow field u formed by the molten metal 3 is created. x,y,z,t The changes occur in the immersion injection tube 5 and / or in the crystallizer 4, thereby improving the reproducibility of continuous casting.

[0040] Therefore in Figure 2 It can be observed that the closure plug 7, guided along the second moving trajectory 11, acts hydrodynamically on the symmetrically disordered flow field 13. Furthermore, this action is relatively dynamic, thus achieving high-quality continuous casting in a reproducible manner. For example, this can reduce the waviness W of the surface 21a of the liquid level 21 in the liquid bath 6 of the crystallizer 4, such as... Figure 3a It can be observed in the middle.

[0041] Since the gap area between the sealing plug 7 and the inlet 5a of the immersion injection tube 5 remains constant, the volumetric flow rate of the molten metal 3 through the immersion injection tube 5 remains approximately the same as the sealing plug 7 moves along the second moving trajectory 11. This ensures that the average liquid level P at the liquid bath 6 of the crystallizer 4 remains the same.

[0042] Advantageously, in order to detect the profile of the surface 21a of the molten metal 3 in the crystallizer 4, multiple sensors 14 of the device 18 are used, such as... Figure 2 This can be observed in the liquid bath 6. For example, the undesirable surface undulation W can be detected by measuring the distance to the liquid bath 6. Accordingly, the device 18 manipulates the manipulator 8 in a different sequence to reduce the surface undulation W of the liquid bath 6 by moving the closure plug 7.

[0043] Additionally from Figure 2It can be observed that the closure plug 7 can move in both translational and rotational directions, with translational degrees of freedom x, y, z and rotational degrees of freedom. China Mobile.

[0044] For example, translational degrees of freedom x, y, and z can be achieved via the translation axis or the rotation axis of the manipulator 8. Translational degrees of freedom x, y, and z can be achieved, for example, via the rotation axis of the manipulator 8.

[0045] like Figure 2 As can be observed, the manipulator 8 consists of a robotic arm 17 with six degrees of freedom (6DoF), namely an articulated robotic arm (RRR configuration), and for this purpose has six non-redundant axes 10a, 10b, 10c, 10d, 10e, and 10f, which are rotational axes. The manipulator can thus move the closed plug 7 in translational degrees of freedom (x, y, z) and rotational degrees of freedom. China Mobile.

[0046] This allows the sealing plug 7 to be moved, for example, around the inlet 5a of the immersion tube 5.

[0047] Furthermore, during this movement, purge gas 16 is introduced into the molten metal 3 from the purge gas port 15 of the sealing plug 7. The purge gas port 15 is centrally located on the sealing plug 7.

[0048] exist Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 5a , Figure 5b , Figure 6a and Figure 6b The diagram exemplarily illustrates the method for altering the formed or existing flow field of the molten metal 3 in the continuous casting equipment 1. x,y,z,t Four method examples.

[0049] Example of the first method:

[0050] according to Figure 3a Scale 20 can be observed in the immersion injection pipe 5. This scale 20 is located in the first side pipe 5b, one of the two side pipes 5b and 5c connected to the central main pipe 5d of the immersion injection pipe 5, and adversely causes asymmetrical flow conditions in the crystallizer 4. This can be observed from the following description, where the transverse flow shape 19a in the first side pipe 5b is clearly different from the transverse flow shape in the second side pipe 5c. The result is a tank level 21. * Surface 21 undulation W * Increase, just as Figure 3aAs can be observed in the middle, it is drawn with a dashed line. In addition, an asymmetric surface 21a is formed at the liquid level 21 in the tank, which is generally characterized by the formation or presence of a flow field with an asymmetric flow condition in the liquid bath 6, with a WDR (Weak Double Roll) 22 on one side and an SDR (Strong Double Roll) 23 on the opposite side.

[0051] According to the present invention, the existing flow field u of the molten metal 3 in the crystallizer 4 is... x,y,z,t The change is achieved by moving the sealing plug 7 from its central position relative to the inlet 5a of the immersion tube 5 in the x / y plane, i.e., as shown below. Figure 3b As can be observed, it is shifted in the y-direction. At the same time, the molten metal 3 flows from the ladle 2 through the immersion pouring pipe 5 into the liquid bath 6 of the crystallizer 4.

[0052] The eccentric annular spacing creates locally different flow velocities and flow rates, resulting in an asymmetric flow field in the submersible injection tube 5. This asymmetric flow field before the movement of the sealing plug 7 is shown as a dashed line in the submersible injection tube. Consequently, different pressures occur at the inlets of the two side tubes 5b and 5c, resulting in the same total volumetric flow rate through both side tubes despite their different cross-sections. This symmetrical and stable crystallizer flow ensures that there are two approximately identical double-vortex rings 23 on both sides of the crystallizer 4. Furthermore, this significantly reduces the undulation W of the tank level 21, such as… Figure 3a As can be observed in the meantime, from the undulation degree W * To the degree of undulation W.

[0053] Example of the second method:

[0054] according to Figure 4a Gas-carrying molten steel flow can be observed, for example, when gas is loaded through the sealing plug 7. This molten steel flow is generated in the main pipe 5d of the immersion injection pipe 5, producing a flow shape in an asymmetrical manner about the pipe axis. This results in a WDR (weak double vortex ring) 22 on one side and an SDR (strong double vortex ring) on ​​the opposite side in the liquid bath 6.

[0055] Disadvantageously, due to the existing flow field u x,y,z,t The surface 21a of the liquid level 21 in the casting tank exhibits strong local variations in its undulation, the amplitude of which changes over time and may also resonate and sway, which greatly reduces the quality of continuous casting.

[0056] According to the present invention, the flow field formed by the molten metal 3 in the crystallizer 4 is changed, and for this purpose the position of the sealing plug 7 relative to the inlet 5a of the immersion injection tube 5 is moved in the x / y plane, i.e., as follows: Figure 4bAs shown, it moves back and forth in the y direction. This preferred periodic movement of the sealing plug 7 along the translational trajectory 11 in the other degree of freedom y alters the resulting flow field.

[0057] On the one hand, as already described in the first method example, this results in symmetrical and stable crystallizer flow with two approximately identical double-vortex rings 23 on both sides of the crystallizer 4. This also reduces fluctuations in the tank level 21.

[0058] On the other hand, by preferably periodically moving the sealing plug 7 back and forth in the y direction, a weaker flow that periodically fluctuates in the crystallizer 4 through the immersion injection tube 5 is counteracted.

[0059] Example of the third method:

[0060] according to Figure 5a and Figure 5b The quality of continuous casting decreases due to the loosening of deposits in the adjustment gap area between the sealing plug 7 and the immersion injection pipe 5, which is also known as "dredging".

[0061] According to the present invention, the flow field u formed by the molten metal 3 in the crystallizer 4 is... x,y,z,t The change is achieved by rotating the sealing plug 7 about the z-axis relative to the inlet 5a of the immersion tube 5. The manipulator 8 thereby moves the sealing plug 7, which has a third degree of freedom φz, along a second rotational trajectory 11, while the molten metal 3 flows from the ladle 2 through the immersion tube 5 into the liquid bath 6 of the crystallizer 4.

[0062] The flow in the molten metal 3 is influenced by rotating the sealing plug 7 around the z-axis. This generates or enhances eddies in the flow field. These eddies reduce the likelihood of scaling. Furthermore, these eddies increase the flow impulse and velocity, resulting in higher shear stresses relative to a static environment. Existing scale can thus be separated. This avoids "clogging," ensuring the quality of continuous casting.

[0063] Furthermore, as the sealing plug 7 moves along the second moving trajectory 11, purge gas 16 is discharged from the purging gas port 15, which is eccentrically opened on the sealing plug 7. By introducing purge gas in this eccentric manner through one or more purge gas ports of the rotating sealing plug 7 at the interface between the refractory surface of the continuous casting equipment 1 and the molten metal 3, undesirable scaling (e.g., alumina scaling) on ​​the refractory surface of the continuous casting equipment 1 wetted by the molten metal 3 can be particularly prevented.

[0064] By rotating the sealing plug 7 around the z-axis, the flow shape of the flow field can be stabilized and made more robust in the face of disturbances.

[0065] Example of the fourth method:

[0066] according to Figure 6a and 6b The remaining amount of molten metal 3 in ladle 2 is reduced, which is necessary for the anti-interference operation of the continuous casting equipment. Therefore, the flow field u of the molten metal 3 in crystallizer 4 is... x,y,z,t The change is achieved by rotating the sealing plug 7 about the z-axis relative to the inlet 5a of the immersion pouring tube 5. This reduces the eddies in the ladle caused by Coriolis acceleration due to the Earth's rotation. This reduces the risk of impurities on the ladle's surface being carried into the pouring channel. Longer pours can be achieved, and thus more output from a full ladle.

[0067] Furthermore, this rotational movement of the sealing plug 7 avoids or at least reduces fluctuations in the tank level 21 in the crystallizer 4, fluctuations that could be triggered, for example, by the breakage of alumina scale within the regulating gap area (so-called "unblocking"). The altered flow field prevents the deposition of alumina particles due to additional wall shear stress induced by the rotation of the sealing plug 7.

[0068] Optionally, for cleaning purposes, purge gas 16 can be additionally introduced into the molten metal 3 through the sealing plug 7.

[0069] Generally, "particularly" can be translated as "more particularly" in English. Features preceded by "particularly" should be considered optional features that can be omitted, and therefore do not constitute a limitation for, for example, the claims. The same applies to "preferably," which is translated as "preferably" in English.

Claims

1. A method for continuously casting billets, particularly a method for continuously casting billets in a sustained manner, wherein, especially during the drawing of the billets, Molten metal (3) flows from a ladle (2) with a closed plug (7) into the liquid bath (6) of the crystallizer (4) via at least one immersion injection pipe (5). Specifically, molten metal (3) flows from an intermediate ladle with a closed plug into the liquid bath (6) of the crystallizer (4) via at least one immersion injection pipe (5), and wherein... By moving the sealing plug (7) in the first degree of freedom (z) using the manipulator (8) connected to the sealing plug (7), and particularly by moving the sealing plug along the first movement trajectory (9) using the manipulator (8) connected to the sealing plug (7), the volumetric flow rate of the molten metal (3) flowing through the immersion injection tube (5) is set and / or adjusted via the sealing plug (7). A flow field (u) is generated in the molten metal (3) at least from the ladle (2) to the crystallizer (4). x,y,z,t ), Its features are, When the molten metal (3) flows from the ladle (2) through the submerged injection pipe (5) into the liquid bath (6) of the crystallizer (4), especially when the molten metal (3) flows from the ladle (2) through the submerged injection pipe (5) into the liquid bath (6) of the crystallizer (4) during the pulling out of the continuous casting billet, the manipulator (8) moves the sealing plug (7) in at least one additional degree of freedom (x, y, φx, φy, φz) different from the first degree of freedom, especially along the second movement trajectory (11), and thereby acts on the molten metal (3) in a hydrodynamic manner to change the resulting flow field (u x,y,z,t ).

2. The method according to claim 1, characterized in that, During movement, the sealing plug (7) acts hydrodynamically on the molten metal (3), resulting in a flow field (u) at least from the ladle (2) to the crystallizer (4). x,y,z,t ) has changed.

3. The method according to claim 1 or 2, characterized in that, Utilizing the flow field (u) that changes within the crystallizer (4) x,y,z,t This is to reduce the undulation (W) of the liquid level surface (21a) of the liquid bath (6) and / or reduce the fluctuation of the liquid level (21) of the liquid bath (6) of the crystallizer (4).

4. The method according to any one of claims 1 to 3, characterized in that, Utilizing the flow field (u) that changes within the crystallizer (4) x,y,z,t This is to make the two vortex regions (DR) rotating in opposite directions within the liquid bath (6) of the crystallizer (4) symmetrical.

5. The method according to any one of claims 1 to 4, characterized in that, Utilizing the changed flow field (u) x,y,z,t ( ) to remove or prevent scaling, especially to remove or prevent scaling in the immersion injection tube (5).

6. The method according to any one of claims 1 to 5, characterized in that, Utilizing the changed flow field (u) x,y,z,t This reduces the amount of molten metal (3) remaining in the ladle (2).

7. The method according to any one of claims 1 to 6, characterized in that, As the sealing plug (7) moves in the at least one additional degree of freedom (x, y, φx, φy, φz), the volumetric flow rate of the molten metal (3) through the immersion injection tube (5) is approximately the same.

8. The method according to any one of claims 1 to 7, characterized in that, At least one sensor (14) of the device (18) detects the contour of the surface (21a) of the tank level (21), and the device (18) manipulates the manipulator (8) to move the sealing plug (7).

9. The method according to any one of claims 1 to 8, characterized in that, The other degrees of freedom (x, y, φx, φy, φz) are translational degrees of freedom (x, y) or rotational degrees of freedom (φx, φy, φz).

10. The method according to any one of claims 1 to 9, characterized in that, The manipulator (8) moves the closure plug (7) in a translational and / or rotational manner in a plurality of additional degrees of freedom (x, y, φx, φy, φz), and in particular, the manipulator moves the closure plug in a translational and / or rotational manner in at least two additional degrees of freedom (x, y, φx, φy, φz).

11. The method according to any one of claims 1 to 10, characterized in that, When the sealing plug (7) is moved in the at least one other degree of freedom (x, y, φx, φy, φz), purge gas (16) is discharged from the sealing plug (7) through at least one purge gas port (15) opened on the sealing plug (7), preferably, purge gas is discharged from the sealing plug through at least one purge gas port (15) opened on the sealing plug in an eccentric manner.

12. The method according to claim 11, characterized in that, When the purge gas (16) is discharged from the sealing plug, the manipulator (8) causes the sealing plug (7) to rotate about the rotation axis (φx, φy, φz).

13. The method according to any one of claims 1 to 12, characterized in that, The manipulator (8) is configured as a robotic arm (17), and in particular, the manipulator is configured as a robotic arm with six degrees of freedom (6DoF).

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