Continuous casting equipment

Abstract

The invention relates to a continuous casting nozzle for manufacturing a composite metal slab, said nozzle being located between a tundish and a crystallizer, said nozzle comprising:-an upper part arranged downstream of the tundish,-a dome arranged at the inlet of the upper part, comprising means for separating an initial flow of liquid metal, the invention relates to a powder mixing device comprising:-a dome,-an inner wall located below the dome creating at least two mixing chambers,-means for injecting powder through the dome to allow mixing with liquid metal,-a lower part comprising at least a central channel having two laterally downward outlets and a side channel having at least one laterally upward outlet, liquid metal is allowed to flow into the crystallizer through the channel. The invention also relates to a method for continuous casting using a continuous casting nozzle associated with the invention.

Description

[0001] The present invention relates to continuous casting equipment. Specifically, the present invention relates to a continuous casting nozzle for manufacturing a composite metal slab, which has an improved design.

[0002] The continuous casting of steel is a well-known process. It involves injecting liquid metal from a ladle into a tundish for flow regulation, and then injecting the metal into the upper part of a water-cooled bottomless copper mold that undergoes vertical reciprocating motion. The solidified semi-finished product is taken out from the lower part of the mold by rolls. The liquid metal is introduced into the mold by means of a tubular conduit called a nozzle disposed between the tundish and the mold.

[0003] However, such a simple device is not suitable for casting composite metal products. The nozzle is a simple conduit that can only be used as a pouring tool for liquid metal between the tundish and the mold. Therefore, the nozzle and the casting method must be modified to allow the casting of composite metal products.

[0004] Japanese Patent Application JP11197807 describes a continuous casting nozzle for manufacturing multi-layer castings, which is formed by a vertical conduit having a plurality of discharge ports in the vertical direction. The conduit is internally separated by partition walls to form a plurality of molten steel flow passages, and has one or more ports for adding raw materials.

[0005] The described continuous casting nozzle allows two types of molten metal with different compositions to be injected into the mold at different heights, thereby forming two liquid metal pools, namely an upper pool and a lower pool, each with a different composition. The metal located in the upper pool solidifies first, forming a shell with the composition of the upper pool. The metal located in the lower pool then solidifies inside the shell, forming the main body of the material piece and having the composition of the lower pool, thus producing a composite metal product.

[0006] When manufacturing composite metal products by continuous casting, to obtain high-quality products, it is necessary to achieve very good stability of the two liquid metal pools entering the mold and the liquid metal flow from the nozzle, and very good uniformity of the pool compositions.

[0007] Japanese Patent Application JP11197807 uses a static magnetic field, and injects different liquid metal flows above and below the magnetic field to stabilize the two pools.

[0008] However, the solutions proposed in the prior art do not provide sufficient solutions in terms of the stability of different liquid metal flows and the uniformity of liquid metal pools. In addition, the specific magnetic field brings complexity to the casting operation.

[0009] The present invention discloses a continuous casting nozzle for manufacturing a composite metal slab, which has an improved design, thereby allowing better stability of the liquid metal flow and better uniformity of the liquid metal bath in the case of simple equipment.

[0010] A first object of the present invention is a continuous casting nozzle for manufacturing a composite metal slab, the nozzle 1 being located between a tundish 2 and a mold 3, the nozzle 1 comprising:

[0011] - an upper part 4, which is arranged downstream of the tundish 2 with respect to the direction of travel of the liquid metal,

[0012] - a dome 6, which is arranged at the inlet of the upper part 4, the dome 6 comprising means for dividing an initial liquid metal flow into at least two separate flows,

[0013] - an inner wall 8, which is located below the dome 6 and generates at least two mixing chambers 9a, 9b, the separate flows of liquid metal flowing in each of the mixing chambers 9a, 9b,

[0014] - means 10 for injecting powder through the dome 6 into at least one of the chambers 9a, 9b to allow mixing with the liquid metal flowing into the chambers 9a, 9b,

[0015] - a lower part 5, which at least comprises a central channel 12a and side channels 12b, 12c, the central channel 12a and the side channels 12b, 12c extending from the upper part 4 into the mold 3, the central channel 12a being connected to one of the chambers 9a, 9b, the central channel 12a being longer than the side channels 12b, 12c, and the side channels 12b, 12c being connected to at least another chamber 9b, wherein the central channel 12a allows liquid metal to flow into the mold 3 through at least two lateral downward outlets 14, and the side channels 12b, 12c allow liquid metal to flow into the mold 3 through at least one lateral upward outlet 13 of each channel.

[0016] The continuous casting nozzle according to the present invention may also have optional features which are considered individually or in combination as listed below:

[0017] - The axis of the lower outlet 14 has an angle α with respect to the horizontal plane,

[0018] - The axis of the upper outlet 13 has an angle β with respect to the horizontal plane,

[0019] - The bottom of the side channels 12b, 12c has a shape selected from the following at the horizontal height of the upper outlet 13: a flat shape, a concave shape or a ramp shape,

[0020] - The bottom of the central channel 12a has a shape selected from the following between the two lower outlets 14: a flat shape, a concave shape, or a domed shape,

[0021] - The dome 6 further includes means 11 for injecting gas through the dome 6,

[0022] - The dome further includes a support arm 7.

[0023] A second object of the present invention is a method for continuously casting a composite metal slab using the continuous casting nozzle 1 according to the present invention, wherein:

[0024] - Liquid metal is injected into a tundish 2 located above the continuous casting nozzle 1,

[0025] - The liquid metal flows from the tundish 2 into the upper part 4 of the casting nozzle 1, thereby forming an initial flow,

[0026] - The initial flow impinges on the dome 6, thereby dividing it into a defined number of separate flows,

[0027] - The separate flows flow into the mixing chambers 9a, 9b of the nozzle 1,

[0028] - Powder is injected into one of the chambers 9a, 9b and is mixed with the liquid metal flow flowing into the chambers 9a, 9b, thereby changing the composition of the liquid metal flow,

[0029] - Then the separate flows are distributed into the channels 12a, 12b, 12c of the lower part of the continuous casting nozzle 1,

[0030] - The liquid metal is injected into a mold 3, wherein the liquid metal flowing in the side channels 12b, 12c is injected into the mold through the upper outlets 13, and the liquid metal flowing into the central channel 12a is injected deeper into the mold through the lower outlets 14, thereby forming two different liquid metal pools 15, 16 in the mold 3.

[0031] The continuous casting method according to the present invention may also have optional features considered individually or in combination listed below:

[0032] - The liquid metal is steel,

[0033] - Powder is injected into the chamber 9a connected to the central channel,

[0034] - The liquid metal in the upper pool 15 in the mold 3 consists only of the base metal from the tundish 2, and the liquid metal in the lower pool 16 in the mold 3 consists of the base metal from the tundish 2 mixed with the powder injected below the dome 6,

[0035] - The powder is injected into chamber 9b connected to the side channels.

[0036] - The liquid metal in the upper molten pool 15 in the crystallizer 3 is formed by mixing the base metal from the tundish 2 with the powder injected below the dome 6, and the liquid metal in the lower molten pool 16 in the crystallizer 3 consists only of the base metal from the tundish 2.

[0037] The present invention will be described in a non - limiting manner with reference to the following figures:

[0038] - Figure 1 : General view of the nozzle in the use configuration according to the present invention.

[0039] - Figure 2 : View of the bottom of the lower part of the nozzle.

[0040] - Figure 3 : Dome as viewed from above for the bulk alloying embodiment.

[0041] - Figure 4 : Dome as viewed from above for the shell alloying embodiment.

[0042] - Figure 5 : Cross - sectional view A - A of the upper part of the nozzle below the dome in Figure 1 : where different embodiments exist for the shape of the bottom of the side channels, a: flat shape, b: concave shape, c: ramp shape.

[0043] - Figure 6 : Upper outlet, where different embodiments exist for the shape of the bottom of the side channels, a: flat shape, b: concave shape, c: ramp shape.

[0044] - Figure 7 : Lower outlet, where different embodiments exist for the shape of the bottom of the central channel, a: flat shape, b: concave shape, c: dome - shaped.

[0045] - Figure 8 : Cross - sectional view B - B of the crystallizer and the nozzle with a representation of convection.

[0046] - Figure 9 : Immersion part of the nozzle with a representation of the flow in the crystallizer.

[0047] - Figure 10 : Cross - section of the composite metal slab obtained by continuous casting.

[0048] - Figure 11 : Figure 1 Cross - sectional view of the mixing chamber of the nozzle.

[0049] The object of the present invention is to cast a composite metal slab. The cross-section of the slab is rectangular, with two long sides and two short sides, as Figure 10 shown.

[0050] Figure 1 Shown is a nozzle 1 disposed between a tundish 2 and a mold 3 and adapted for casting a slab having two long faces and two narrow faces. The nozzle 1 includes an upper part 4 and a lower part 5.

[0051] A dome 6 is provided at the inlet of the upper part 4 and closes a part thereof. The top of the dome 6 preferably has an inclined surface at a certain angle, for example greater than 15°. The dome 6 also has lateral sides which preferably form a sharp edge with the inclined surface. The dome 6 is fixed to the upper part 4 by one or more support arms 7.

[0052] An inner wall 8 located below the dome 6 creates at least two mixing chambers 9a, 9b in the upper part 4. In Figure 1 the configuration shown, there are two chambers 9a, 9b.

[0053] The upper part 4 also includes means 10 for injecting powder and means 11 for injecting gas, and the means 10 and the means 11 are each partially located in one of the support arms 7 and pass through the dome 6. The means 10 for injecting powder can be, for example, a worm screw connected to a powder tank.

[0054] Figure 3 Shown is the configuration of the dome 6 which has three support arms 7 and has a passage 10 for powder injection located in one of the support arms 7 and two passages 11 for gas injection located in the other two support arms 7.

[0055] Figure 4 Shown is another configuration of the dome 6 which also has three support arms 7, but different from the Figure 3 configuration shown, it has two passages 10 for powder injection located in two of the support arms 7 and one passage 11 for gas injection located in the other support arm 7. In this configuration, the two passages 10 for powder injection can be connected to two different powder injectors, and the powder injectors each have different types of powder.

[0056] The dome 6 can also include other configurations with fewer or more support arms. For example, a configuration with four support arms 7 can be considered.

[0057] As Figure 1 shown, the lower part 5 of the nozzle 1 includes three channels 12a, 12b, 12c which extend from the mixing chambers 9a, 9b of the upper part 4 and terminate at the mold 3.Figure 2 Shows a magnified view of the bottom of the lower part 5 of the nozzle 1 for the configuration shown in Figure 1 . The side channels 12b, 12c lead to the crystallizer 3 via two upper outlets 13, where there is one upper outlet for each channel. The central channel 12a leads to the crystallizer via two lower outlets 14. The axis of the lower outlet 14 forms an angle α with respect to the horizontal plane. The angle α is preferably from 15° to 40°. The axis of the upper outlet 13 forms an angle β with respect to the horizontal plane. The angle β is preferably from -10° to 10°. These angles are directed downwards.

[0058] In this embodiment, the channels 12a, 12b, 12c have a circular shape. In a preferred embodiment, the channels 12a, 12b, 12c have a circular or elliptical cross-section.

[0059] Figure 5 Shows a cross-sectional view A-A of the nozzle 1 in the configuration depicted in Figure 1 . Figure 3 And Figure 4 Are arranged in the same orientation as Figure 5 . Figure 3 Can be overlapped with Figure 5 To obtain a cross-sectional view of the nozzle 1 above the dome 6. This can also be applied to Figure 4 And Figure 5 To obtain a view of another configuration.

[0060] As shown in Figure 5 , the inner wall 8 has a V-shaped shape, thus forming two mixing chambers 9a, 9b with different volumes. The chamber 9a located inside the V-shaped shape is connected to the central channel 12a, and the chamber 9b located outside the V-shaped shape is connected to the side channels 12b, 12c.

[0061] In other configurations, the inner wall 8 has a different shape and forms a different number of chambers. For example, a Y-shaped shape can form three chambers with different volumes, or a simple wall can form two chambers with exactly the same volume.

[0062] As shown in Figure 1 , the central channel 12a is longer than the two side channels 12b, 12c, and thus leads deeper into the crystallizer 3. In this embodiment, the three channels are aligned, as shown in Figure 5 .

[0063] Other configurations can be considered. For example, a third side channel that is not aligned with the other channels 12a, 12b, 12c can be added to form another geometry.

[0064] Figure 6 Shows different embodiments of the shape of the bottom of the side channels 12b, 12c at the horizontal height of the upper outlet 13.Figure 6 In a, a flat shape is shown. The bottoms of the side channels 12b and 12c are flat and at the same level as the bottom of the outlet 13. Figure 6 In b, a recessed shape is shown. The bottoms of the side channels 12b and 12c are also flat, but lower than the bottom of the outlet 13, thus forming a recess. Figure 6 In c, a ramp shape is shown. The bottoms of the side channels 12b and 12c form ramps that terminate at the bottom of the outlet 13. In other embodiments, other shapes may be used.

[0065] Figure 7 Different embodiments of the shape of the bottom of the central channel 12a at the level of the lower outlet 14 are shown. Figure 7 In a, a flat shape is shown. The bottom of the central channel 12a is flat and at the same level as the bottom of the outlet 14. Figure 7 In b, a recessed shape is shown. The bottom of the central channel 12a is also flat, but lower than the bottom of the outlet 14, thus forming a recess. Figure 7 In c, a dome shape is shown. The bottom of the central channel 12a forms a dome that terminates at the bottom of the outlet 14. In other embodiments, other shapes may be used.

[0066] In a preferred embodiment, the ratio between the diameter of the outlets 13 and 14 and the distance between the outlet 13 and the mold 3 is greater than 0.05 and less than 0.2.

[0067] In a preferred embodiment, the ratio between the diameter of the upper outlet 13 and the diameters of the side channels 12b and 12c is greater than 0.4 and less than 1.2. In this particular embodiment, the ratio between the diameter of the lower outlet 14 and the diameter of the central channel 12a is greater than 0.4 and less than 1.

[0068] The present invention has two preferred embodiments for its uses, which are respectively referred to as bulk alloying and shell alloying. Only the differences between the two preferred embodiments will be separately described. Figure 1 The present invention in a use configuration is shown.

[0069] Liquid metal of a specified composition is poured from the ladle into the tundish 2. In a preferred embodiment, the liquid metal is steel, and the use of the nozzle 1 will be described together with it. The steel flows into the upper part 4 of the continuous casting nozzle 1, thus forming an initial flow. The stopper rod 23 allows controlling the initial flow rate.

[0070] The dome 6 placed on a track made of steel forces the initial flow to impact on the dome 6. The slope of the dome 6 causes the steel to flow towards its edge. The support arms 7 form different regions on the dome 6, thereby dividing the steel into multiple separate flows. The number of separate flows is determined by the design of the dome 6 and its support arms 7. In this particular embodiment, the number of separate flows is three.

[0071] The separate flows then flow into different mixing chambers 9a, 9b. Figure 11 A cross-sectional view of the mixing chamber is shown. In this configuration, a part of the flow flows into the chamber 9a inside the V-shaped form, and another part flows into the chamber 9b outside the V-shaped form. The powder is simultaneously injected into one of the mixing chambers 9a, 9b. The design of the chamber having a large cross-section at the top allows the steel to flow down from the dome like a waterfall, and allows the powder to be injected into the flow without the steel contacting the device for injecting the powder. The reduction of the cross-section of the chamber allows the steel to decelerate and accumulate in the chambers 9a, 9b. The reduction of the cross-section of the chamber allows the steel to be agitated inside the chamber. Thus, the powder can be effectively mixed with the steel entering the chambers 9a, 9b to change its composition, and the powder starts to melt. This step allows the liquid steel injected with the powder to become uniform. The reduction of the cross-section of the chamber can be achieved by walls of various configurations. For example, the reduction can be accomplished with regular slopes or steps or any method of reducing the cross-section.

[0072] The powder injected into the steel can have various compositions. For example, it can be FeSi, Ni, FeAl, FeTi, FeCr, FeNb, FeB, FeCe, FeMo, etc.

[0073] The powder addition step is different between two preferred embodiments. For the bulk alloying embodiment, the powder is injected into the chamber 9a inside the V-shaped form by means of at least one powder injection device 10, Figure 3 only one injection device is shown, while for the shell alloying embodiment, the powder is injected into the chamber 9b outside the V-shaped form by means of at least one powder injection device 10, Figure 4 two powder injection devices are shown.

[0074] In both embodiments, the injection of the powder is facilitated by a gas injection device 11 which generates a gas flow that keeps the steel flowing downward along the dome 6 towards the outside of the upper part 4, thereby forming a steel-free zone below the dome 6. This hollow zone prevents any contact between the steel and the powder injection device 10, thus avoiding potential clogging of the powder injection device 10.

[0075] The gas is preferably a non-oxidizing gas, such as argon, to prevent any reaction with the steel during casting.

[0076] After injection, the two mixing chambers 9a, 9b contain two types of steel with different compositions.

[0077] Then, the steel flows into the channels 12a, 12b, 12c of the lower part 5 of the nozzle 1, which are connected to the chambers after the cross-section of the chambers is reduced, as Figure 1 or Figure 11 shown. The steel in the chamber 9a located inside the V-shape flows into the central channel 12a, and the steel in the chamber 9b located outside the V-shape flows into the side channels 12b, 12c. Then, the different steels are injected into the mold 3 through the outlets 13, 14 of the channels 12a, 12b, 12c.

[0078] Since the central channel 12a is longer than the side channels 12b, 12c, the steel from the central channel 12a is injected deeper into the mold 3. This configuration allows the two types of steel to be injected into the mold 3 at different heights, thus creating two steel molten pools, namely the upper molten pool 15 and the lower molten pool 16 with different compositions. The upper molten pool 15 is formed by the steel from the side channels 12b, 12c, and the lower molten pool 16 is formed by the steel from the central channel 12a.

[0079] During use, the outlets 13, 14 of the nozzle 1 are immersed in different steel molten pools. The upper outlets 13 of the side channels 12b, 12c are immersed in the upper molten pool 15, and the lower outlet 14 of the central channel 12a is immersed in the lower molten pool 16.

[0080] According to the embodiment, the compositions of the molten pools are different.

[0081] For the bulk alloying embodiment, the composition of the upper molten pool 15 is only the composition of the steel from the tundish 2. The composition of the lower molten pool 16 is a combination of the composition of the steel from the tundish 2 and the composition of the injected powder.

[0082] For the shell alloying embodiment, the composition of the upper molten pool 15 is a combination of the composition of the steel from the tundish 2 and the composition of the injected powder. The composition of the lower molten pool 16 is only the composition of the steel from the tundish 2.

[0083] In both embodiments, in the mold 3, the steel in the upper molten pool 15 solidifies first, thus forming the shell 17. The steel in the lower molten pool 16 then solidifies inside the shell 17, thus forming the body 18 of the material piece. After complete solidification, the obtained material piece is a composite metal slab, which has different compositions in its shell and its body.

[0084] To cast a composite metal slab with sufficient quality, each molten pool must have a uniform composition, and the boundary between them must be stable. These factors are affected by the characteristics of the different liquid metal flows from the nozzle 1.

[0085] The design of the nozzle 1 with at least two lateral upward outlets 13 and at least two lateral downward outlets 14 allows the flow in the mold to be directed towards the narrow faces and reach the narrow faces, as Figure 8 shown, thus ensuring the uniformity of the two molten pools 15, 16.

[0086] These flows generated by the design of the nozzle ensure the stability of the boundary between the two molten metal pools 15, 16.

[0087] For example, in the configuration shown in Figure 9 , the flow from the upper outlet 13 forms a main upward flow 19 and a secondary downward flow 20 with a smaller flow rate in the upper molten pool 15 when it meets the narrow face of the mold 3. Conversely, the flow from the lower outlet 15 forms a main downward flow 21 and a secondary upward flow 22 with a smaller flow rate in the lower molten pool 16 when it meets the narrow face of the mold 3.

[0088] The design of the outlets affects the stability and uniformity of the boundary between the two molten pools because the outlets affect the initial direction and velocity of the flow. Those skilled in the art will determine the characteristics of the outlets 13, 14 to optimize these parameters. Among these characteristics, the ratio of the diameter of the outlet to the diameter of the channel, the ratio of the diameter of the outlet to the distance between the outlet and the mold 3, and the angles α and β of the axis of the outlet relative to the horizontal plane can be considered.

[0089] In a preferred embodiment, the angle α of the axis of the lower outlet 14 relative to the horizontal plane is between 15° and 40°, and the angle β of the axis of the upper outlet relative to the horizontal plane is between -10° and 10°, because this allows the stability of the two molten pools to be optimized.

[0090] In a preferred embodiment, the ratio of the diameters of the outlets 13, 14 to the distance between the outlet 13 and the mold 3 is greater than 0.05 and less than 0.2.

[0091] For the bulk alloying embodiment, the preferred ratio of the diameter of the upper outlet 13 to the diameters of the side channels 12b, 12c is greater than 0.8 and less than 1.2. In this particular embodiment, the ratio of the diameter of the lower outlet 14 to the diameter of the central channel 12a is greater than 0.6 and less than 1.

[0092] For the shell alloying embodiment, the preferred ratio of the diameter of the upper outlet 13 to the diameters of the side channels 12b, 12c is greater than 0.4 and less than 0.8. In this particular embodiment, the ratio of the diameter of the lower outlet 14 to the diameter of the central channel 12a is greater than 0.4 and less than 0.8.

[0093] The different shapes of the channels at the horizontal height of the outlets also affect the stability of the boundary.

[0094] In a preferred embodiment, the bottom of the central channel 12a has a domed shape at the level of the lower outlet 14, as this allows for optimal stability of the boundary. In another embodiment, the bottom of the central channel 12a has a flat shape or a recessed shape at the level of the lower outlet 14.

[0095] For the bulk alloying embodiment, the preferred shape of the bottom of the side channels 12b, 12c at the level of the upper outlet 13 is a flat shape, as this allows for optimal stability of the boundary. In another embodiment, the bottom of the side channels 12b, 12c has a recessed shape or a ramp shape at the level of the upper outlet 13.

[0096] For the shell alloying embodiment, the preferred shape of the bottom of the side channels 12b, 12c at the level of the upper outlet 13 is a flat shape or a recessed shape, as this allows for optimal stability of the boundary. In another embodiment, the bottom of the side channels 12b, 12c has a ramp shape at the level of the upper outlet 13.

[0097] In a preferred embodiment, the nozzle 1 consists mainly of refractory material surrounded by a metal ring.

[0098] The continuous casting nozzle 1 meets the expectations in terms of stability and uniformity in its use configuration. It allows for a stable casting speed, and the different liquid metal flows allow for a high degree of stability and a high degree of uniformity in the heights of the two molten pools entering the mold 3. This stability results in a high-quality semi-finished product that has a well-defined compositional gradient between its shell and its body.

Claims

1. A continuous casting nozzle (1) for manufacturing a composite metal slab, the nozzle (1) being located between a tundish (2) and a mold (3), the nozzle (1) comprising: - an upper part (4), the upper part (4) being arranged downstream of the tundish (2) with respect to the direction of travel of the liquid metal, - a dome (6), the dome (6) being arranged at the inlet of the upper part (4), the dome (6) comprising means for dividing an initial liquid metal stream into at least two separate streams, - an inner wall (8), the inner wall (8) being located below the dome (6), thereby creating at least two mixing chambers (9a, 9b), the separate streams of liquid metal flowing in each of the chambers (9a, 9b), - means (10) for injecting powder through the dome (6) into at least one of the chambers (9a, 9b) to allow mixing with the liquid metal flowing into the chambers (9a, 9b), - a lower part (5), the lower part (5) comprising at least a central channel (12a) and side channels (12b, 12c), the central channel (12a) and the side channels (12b, 12c) extending from the upper part (4) into the mold (3), the central channel (12a) being connected to one of the chambers (9a, 9b), the central channel (12a) being longer than the side channels (12b, 12c), and the side channels (12b, 12c) being connected to at least another chamber (9b), wherein the central channel (12a) allows the liquid metal to flow into the mold (3) through at least two lateral downward outlets (14), and the side channels (12b, 12c) allow the liquid metal to flow into the mold (3) through at least one lateral upward outlet (13) of each channel.

2. The continuous casting nozzle (1) according to claim 1, wherein, The axis of the lower outlet (14) has an angle α with respect to the horizontal plane.

3. The continuous casting nozzle (1) according to claims 1 and 2, wherein, The axis of the upper outlet (13) has an angle β with respect to the horizontal plane.

4. The continuous casting nozzle (1) according to any one of the preceding claims, wherein, The bottom of the side channels (12b, 12c) has a shape selected from the following at the horizontal height of the upper outlet (13): a flat shape, a concave shape or a ramp shape.

5. The continuous casting nozzle (1) according to any one of the preceding claims, wherein, The bottom of the central channel (12a) has a shape selected from the following between the two lower outlets (14): a flat shape, a concave shape or a domed shape.

6. The continuous casting nozzle (1) according to any one of the preceding claims, wherein, The dome (6) further comprises means (11) for injecting gas through the dome (6).

7. The continuous casting nozzle (1) according to any one of the preceding claims, wherein, The dome further comprises a support arm (7).

8. A method for continuously casting a composite metal slab using the continuous casting nozzle (1) according to any one of the preceding claims, wherein: - injecting liquid metal into a tundish (2) located above the continuous casting nozzle (1), - the liquid metal flowing from the tundish (2) into the upper part (4) of the casting nozzle (1), thereby forming an initial stream, - the initial stream impinging on the dome (6), thereby dividing the initial stream into a defined number of separate streams, - The separated flow flows into the mixing chambers (9a, 9b) of the nozzle (1), - Powder is injected into one of the chambers (9a, 9b), and the powder is mixed with the liquid metal flow flowing into the chambers (9a, 9b), thereby changing the composition of the liquid metal flow, - Then the separated flow is distributed into the channels (12a, 12b, 12c) of the lower part of the continuous casting nozzle (1), - The liquid metal is injected into the mold (3), wherein the liquid metal flowing in the side channels (12b, 12c) is injected into the mold through the upper outlet (13), and the liquid metal flowing into the central channel (12a) is injected deeper into the mold through the lower outlet (14), thereby forming two different liquid metal pools (15, 16) entering the mold (3).

9. The method according to claim 8, wherein The liquid metal is steel.

10. The method according to claim 8 or 9, wherein The powder is injected into the chamber (9a) connected to the central channel.

11. The method according to claim 10, wherein, The liquid metal in the upper pool (15) in the mold (3) consists only of the base metal from the tundish (2), and the liquid metal in the lower pool (16) in the mold (3) consists of the base metal from the tundish (2) mixed with the powder injected below the dome (6).

12. The method according to claim 8 or 9, wherein, The powder is injected into the chamber (9b) connected to the side channel.

13. The method according to claim 12, wherein, The liquid metal in the upper pool (15) in the mold (3) consists of the base metal from the tundish (2) mixed with the powder injected below the dome (6), and the liquid metal in the lower pool (16) in the mold (3) consists only of the base metal from the tundish (2).

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