Continuous casting equipment

Abstract

The invention relates to a continuous casting nozzle for manufacturing a composite metal product having different shells and a body, in which the shells are divided into two parts having different compositions, said compositions being different from the composition of the body, said nozzle comprising:-a dome,-a nozzle body, and-a plurality of nozzles. The invention relates to a powder injection device comprising a dome comprising means for dividing an initial flow of liquid metal into at least two separated flows,-an inner wall located below the dome forming at least two chambers,-means for injecting powder through the dome to allow mixing with the liquid metal,-a lower part comprising at least two channels, the at least two channels extend from the upper portion into the crystallizer and open to the crystallizer by means of at least one lateral outlet of each channel. The invention also relates to a method for continuous casting using the continuous casting nozzle related to the invention and to related products.

Description

Technical Field

[0001] The present invention relates to continuous casting equipment. In particular, the present invention relates to a continuous casting nozzle for producing composite metal products having an improved design. Background Art

[0002] Composite metal materials are a well-known class of products. Because their structure comprises different metals with varying compositions, composite metal materials are characterized by their ability to exhibit varying mechanical properties. Clad steel is an example of a composite metal material, which has a body composed of one type of metal and a surface or outer shell composed of one or two other types of metal.

[0003] However, these products are primarily manufactured using batch processes. Manufacturing methods using continuous processes are very rare.

[0004] European Patent Application EP3804874 describes an apparatus and method for the continuous production of clad metal strip. This method uses a coiled metal as a base metal and adds different metal layers to the surface of the metal using various apparatus and process steps, including a continuous casting step using two different tundishes. This method allows for the continuous production of composite metal products having a body formed from one metal component and an outer shell composed of one or two other metal components.

[0005] However, the solutions proposed in the prior art include too many steps and related devices, thus making them difficult to implement in industrial facilities. Summary of the Invention

[0006] The present invention discloses a continuous casting nozzle for manufacturing a composite metal product having three different metal components, wherein the continuous casting nozzle uses simple equipment and has sufficient stability to obtain high-quality products.

[0007] A first object of the present invention is a continuous casting apparatus for producing a composite metal product having different shells 16a, 16b and a body 17, the continuous casting apparatus comprising a nozzle 1, a tundish 2 and a crystallizer 3, wherein the shells 16a, 16b are divided into two parts having different compositions, the compositions being different from those of the body 17, the nozzle 1 being located between the tundish 2 and the crystallizer 3, the nozzle 1 comprising:

[0008] an upper portion 4 arranged downstream of the tundish 2 with respect to the direction of travel of the liquid metal,

[0009] a dome 6 arranged at the inlet of the upper portion 4, said dome 6 comprising means for dividing the initial liquid metal flow into at least two separate flows,

[0010] an inner wall 8 situated below the dome 6 so as to form at least two chambers 9a, 9b in each of which said separate flows of liquid metal flow,

[0011] - means 10 for injecting powder through the dome 6 into at least one of said chambers 9a, 9b to allow mixing with the liquid metal flowing into said chambers 9a, 9b,

[0012] a lower part 5 comprising at least two channels 12a, 12b extending from the upper part 4 into the crystallizer 3 and opening into the crystallizer 3 by means of at least one lateral outlet 13 of each channel 12a, 12b, wherein one of the channels is connected to one chamber 9a, 9b, said channel allowing the liquid metal to flow into the left part of the crystallizer 3, and wherein the other channel is connected to the other chamber 9a, 9b, said channel allowing the liquid metal to flow into the right part of the crystallizer 3.

[0013] The continuous casting apparatus according to the present invention may also have the optional features listed below, considered individually or in combination:

[0014] - channels 12a, 12b, each channel having at least two outlets,

[0015] - the axis of the outlet 13 is positioned towards the corner of the crystallizer 3,

[0016] - the composite metal product is a slab and the axis of the outlet 13 is positioned towards the narrow face of the crystallizer 3,

[0017] - the dome 6 also comprises means 11 for injecting gas through the dome 6,

[0018] The dome also comprises supporting arms 7 .

[0019] A second object of the present invention is a method for continuously casting a composite metal product having different shells 16a, 16b and a body 17 using a continuous casting apparatus according to any one of the preceding claims, wherein the shells 16a, 16b are divided into two parts having different compositions, said compositions being different from the composition of the body 17, wherein:

[0020] - injecting liquid metal into the tundish 2 located above the continuous casting nozzle 1,

[0021] - the liquid metal flows from the tundish 2 into the upper part 4 of the casting nozzle 1, thereby forming an initial flow,

[0022] - the initial flow impinges on the dome 6, thereby dividing it into at least two separate flows,

[0023] - the separated flow flows into the chambers 9a, 9b of the nozzle 1,

[0024] - injecting a powder into at least one of said chambers 9a, 9b and mixing it with the liquid metal flow flowing into said chambers 9a, 9b, thereby changing the composition of the liquid metal flow,

[0025] - the separated flows are then distributed into the channels 12a, 12b of the lower part of the continuous casting nozzle 1,

[0026] - injecting the liquid metal into the crystallizer 3, wherein the liquid metal flowing in one channel 12b, 12c is injected into the left part of the crystallizer 3 through at least one outlet 13, and the liquid metal flowing into the other channel 12a is injected into the other parts of the crystallizer through at least one outlet 13 of each channel.

[0027] The continuous casting method according to the present invention may also have the optional features listed below, considered individually or in combination:

[0028] -Liquid metal is steel,

[0029] the upstream part 14 of the crystallizer 3 contains two liquid metals of different composition in two sections,

[0030] the composition of the liquid metal in the left part of the upstream part 14 of the mold 3 is formed only by the base metal from the tundish 2, and the composition of the liquid metal in the right part of the upstream part 14 of the mold 3 is formed by the base metal from the tundish 2 mixed with the powder injected under the dome 6,

[0031] - the composition of the liquid metal in the left part of the upstream part 14 of the mold 3 is a mixture of base metal from the tundish 2 and one type of powder injected under the dome 6, and the composition of the liquid metal in the right part of the upstream part 14 of the mold 3 is a mixture of base metal from the tundish 2 and another type of powder injected under the dome 6,

[0032] The downstream part 15 of the crystallizer 3 contains liquid metal, the composition of which is a mixture of the compositions of the two parts coming from the upstream part 14 of the crystallizer 3 .

[0033] A third object of the present invention is a composite metal blank or composite metal block having different shells 16 a, 16 b and a body 17 , wherein the shells 16 a, 16 b are divided into two parts having different compositions, which are different from the composition of the body 17 .

[0034] A fourth object of the present invention is a composite metal sheet blank having different outer shells 16 a , 16 b and a body 17 , wherein the outer shells 16 a , 16 b are divided into two parts having different compositions than the composition of the body 17 . BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The invention will be described in a non-limiting manner with reference to the following drawings:

[0036] - Figure 1 : General view of the nozzle according to the invention in the configuration for use,

[0037] - Figure 2 : The dome as seen from above,

[0038] - Figure 3 :The upper part of the nozzle is in Figure 1 AA section view below the dome,

[0039] - Figure 4 : For billet or briquette type products, BB cross-section of the crystallizer and nozzle with representation of convection,

[0040] - Figure 5 : For slab type products, BB cross-section of the crystallizer and nozzle with representation of convection,

[0041] - Figure 6 : the immersed part of the nozzle, which has a representation of the composition and flow in the crystallizer,

[0042] - Figure 7 : a cross section of a composite metal billet or composite metal ingot obtained by continuous casting according to the present invention,

[0043] - Figure 8 : Cross section of a composite metal slab obtained by continuous casting utilizing the present invention. DETAILED DESCRIPTION

[0044] In the following description, claims, and drawings, directional terms are defined using X, Y, and Z coordinate references, where Z is the direction of flow of the liquid metal, X is the direction parallel to the long sides of the crystallizer, and Y is the direction parallel to the narrow sides of the crystallizer. References are indicated in each apparatus figure. When the drawings are 2D planar representations, following established convention, an axis outside the drawing is represented by a dot in a circle when it points toward the reader and by a cross in a circle when it points away from the reader. In particular, the terms "top," "upper," "upstream," "rising," "above," "bottom," "lower," "below," "downstream," "descending," etc. are defined with respect to the Z axis. The terms "left," "right" are defined with respect to the X axis.

[0045] The present invention is directed to casting composite metal products.

[0046] Figure 1 There is shown a nozzle 1 arranged between a tundish 2 and a crystalliser 3. The nozzle 1 comprises an upper part 4 and a lower part 5.

[0047] A dome 6 is provided at the entrance of the upper portion 4 and partially closes it. The top of the dome 6 preferably has an angled slope, for example, greater than 15°. The dome 6 also has lateral sides that preferably form a sharp edge with the slope. The dome 6 is secured to the upper portion 4 by one or more support arms 7.

[0048] The inner wall 8 located below the dome 6 forms at least two chambers 9a, 9b in the upper part 4. Figure 1 In the configuration shown in , there are two chambers 9a, 9b.

[0049] Also included in the upper part 4 are means 10 for injecting powder and means 11 for injecting gas, each of which is partially located in one of the supporting arms 7 and passes through the dome 6. The means 10 for injecting powder may be, for example, an endless screw connected to the powder tank.

[0050] Figure 2 A configuration of a dome 6 is shown which has four support arms 7 and has one passage 10 for powder injection in one of the support arms 7 and three passages 11 for gas injection in the other three support arms 7. Another configuration, not shown, has two passages 10 for the injection of two powders on two opposing support arms 7.

[0051] The dome 6 may also comprise other configurations with fewer or more support arms 7. For example, configurations with two or three support arms 7 are contemplated.

[0052] like Figure 1 As shown in FIG, the lower part 5 of the nozzle 1 comprises two channels 12a, 12b extending from the chambers 9a, 9b of the upper part 4 and terminating in the crystallizer 3. The channels 12a, 12b open into the crystallizer 3 by means of at least one lateral outlet 13 of each channel 12a, 12b.

[0053] The number and arrangement of the outlets 13 depend on the type of cast product. In the case of billet or briquette type products, the crystallizer 3 has a square cross-section, and therefore, it is preferred that each channel 12a, 12b has at least two outlets 13, wherein the axes of the outlets 13 are positioned towards the corners of the crystallizer 3. In the case of slab type products, the crystallizer 3 has a rectangular cross-section, and therefore, it is preferred that each channel 12a, 12b has at least one outlet 13, wherein the axes of the outlets 13 are positioned towards the narrow faces of the crystallizer 3. Figure 4 and Figure 5 In the figure two configurations of the outlet 13 are shown, depending on the type of product. Figure 4 and Figure 5 The nozzle 1 and the bottom of the crystallizer 3 are shown from above. Figure 4 is a representation of the nozzle 1 in the crystallizer 3 for a billet or briquette type product, and Figure 5 It is a representation of the nozzle 1 in the crystallizer 3 for a slab-type product.

[0054] In the present embodiment, the channels 12a, 12b have a circular shape. In a preferred embodiment, the channels 12a, 12b have a semi-elliptical cross-section.

[0055] Figure 3 Shows the Figure 1 AA cross-section of the nozzle 1 of the configuration described in FIG. Figure 2 With Figure 3 Same orientation settings. Figure 2 Can be used with Figure 3 Overlap to obtain a cross-sectional view of the nozzle 1 above the dome 6.

[0056] like Figure 3 As shown in FIG, the inner wall 8 forms two chambers 9a, 9b having the same volume. Each chamber 9a, 9b is connected to its corresponding channel 12a, 12b.

[0057] In other configurations, the inner wall 8 has a different shape and forms a different number of chambers. For example, in the case of a cross-sectional view, a Y-shape can form three chambers, or a V-shape can form two chambers with different volumes.

[0058] exist Figure 1 The present invention is shown in the configuration for use and will therefore be utilized Figure 1 Its use is described as a reference.

[0059] Liquid metal of a defined composition is poured from a ladle into a tundish 2. In a preferred embodiment, the liquid metal is steel, and the use of the nozzle 1 will be described in conjunction with this. The steel flows into the upper portion 4 of the continuous casting nozzle 1, thereby forming an initial flow. A stopper rod 18 allows for control of the initial flow rate.

[0060] Dome 6, mounted on a steel track, forces the initial stream to impinge on it. The slope of dome 6 causes the steel to flow toward its edge. Support arms 7 create distinct zones on dome 6, thereby dividing the steel into multiple separate streams. The number of separate streams is determined by the design of dome 6 and its support arms 7. In this particular embodiment, there are four separate streams.

[0061] The separated streams then flow into different chambers 9a, 9b. In this configuration, half the stream flows into one chamber 9a, and the other half flows into the other chamber 9b. Powder is injected simultaneously into at least one of the chambers 9a, 9b. The design of the chambers 9a, 9b allows the steel to decelerate and accumulate in the chambers 9a, 9b. As a result, the powder can effectively mix with the steel entering the chambers 9a, 9b, changing its composition, and the powder begins to melt.

[0062] Another configuration, not shown, uses two powder injectors 10 to add different powders to the two chambers 9a, 9b.

[0063] 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.

[0064] The injection of the powder is facilitated by a gas injection device 11 which generates a gas flow that keeps the steel flowing along the dome 6 downwards towards the outside of the upper part 4 of the nozzle 1, 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 blockages of the powder injection device 10.

[0065] The gas is preferably a non-oxidizing gas, such as Ar, to prevent any reaction with the steel during casting.

[0066] After injection, the two chambers 9a, 9b contain two types of steel with different compositions.

[0067] The steel then flows into the channels 12a, 12b of the lower part 5 of the nozzle 1. The steel is then injected into the crystalliser 3 through the outlet 13 of the channels 12a, 12b.

[0068] The configuration of the channels 12 a , 12 b and the outlet 13 allows steel from one chamber 12 a to be injected into the left part of the mold 3 , and steel from the other chamber 12 b to be injected into the right part of the mold 3 .

[0069] Figure 6The submerged portion of the nozzle 1 and the crystallizer 3 are shown, highlighting the different compositions of the steel formed in the crystallizer 3. The upstream portion 14 of the crystallizer 3 is composed of two different steels, which are injected through two channels 12a, 12b, located in the left and right parts of the crystallizer 3. The flow of liquid metal from each outlet 13 is divided into an ascending flow 19 and a descending flow 20. The descending flow eventually forms a vortex type, so that remixing occurs deeper in the crystallizer.

[0070] In the first embodiment, when there is only one powder injection device 10 , the composition of the liquid metal in the left portion is formed only by the base metal from the tundish 2 , and the composition of the liquid metal in the right portion is formed by the base metal from the tundish 2 mixed with the powder injected under the dome 6 .

[0071] In another embodiment, when there are two powder injection devices 10, the composition of the liquid metal in the left portion is a mixture of base metal from the tundish 2 and one type of injected powder, and the composition of the liquid metal in the right portion is a mixture of base metal from the tundish 2 and another type of injected powder.

[0072] Due to the remixing of the liquid metal as it passes downwards into the crystalliser, a downstream portion 15 of the crystalliser 3 is formed which comprises a third composition mixed from the compositions of the two portions coming from the upstream portion 14 of the crystalliser 3 .

[0073] In the crystallizer 3, the steel of the upstream portion 14 solidifies first, forming the outer shells 16a, 16b. The steel of the downstream portion 15 then solidifies within the outer shells 16a, 16b, forming the body 17 of the material. After complete solidification, the resulting material is a composite metal product having distinct outer shells 16a, 16b and a body 17. The outer shells 16a, 16b of the composite metal product are divided into two parts having different compositions, and the body 17 of the composite metal product has a composition different from the two compositions of the outer shells 16a, 16b. The composite metal product allows the cast product to have different properties in the two parts of its outer shells 16a, 16b.

[0074] Two types of products from two preferred embodiments are Figure 7 Indicated as a billet or block type product, and in Figure 8 The middle represents a slab type product.

[0075] In a preferred embodiment, the nozzle 1 consists primarily of a refractory material surrounded by a metal ring.

[0076] In its operational configuration, the continuous casting nozzle 1 meets expectations regarding stability. It allows for a stable casting rate, and the varying liquid metal flows result in a high degree of stability in the various regions of the mold 3. This stability results in a high-quality semi-finished product with a well-defined composition gradient between the two parts of its shell 16a, 16b and its body 17.

Claims

1. A continuous casting apparatus for producing a composite metal product having different shells (16a, 16b) and a body (17), the continuous casting apparatus comprising a nozzle (1), a tundish (2) and a crystallizer (3), wherein: The shell (16a, 16b) is divided into two parts with different compositions, the compositions being different from the compositions of the body (17), the nozzle (1) being located between the tundish (2) and the crystallizer (3), and the nozzle (1) comprising: - an upper portion (4) arranged downstream of the tundish (2) with respect to the direction of travel of the liquid metal, a dome (6) arranged at the inlet of the upper part (4), said dome (6) comprising means for dividing the initial liquid metal flow into at least two separate flows, an inner wall (8) situated below the dome (6) so as to form at least two chambers (9a, 9b), the separate flows of liquid metal flowing in each of the chambers (9a, 9b), - means (10) for injecting powder through said dome (6) into at least one of said chambers (9a, 9b) to allow mixing with said liquid metal flowing into said chambers (9a, 9b), - a lower part (5) comprising at least two channels (12a, 12b) extending from the upper part (4) into the crystallizer (3) and opening into the crystallizer (3) by means of at least one lateral outlet (13) of each channel (12a, 12b), wherein one of the channels is connected to a chamber (9a, 9b) allowing the liquid metal to flow into the left part of the crystallizer (3), and wherein the other channel is connected to the other chamber (9a, 9b) allowing the liquid metal to flow into the right part of the crystallizer (3).

2. The continuous casting apparatus according to claim 1, wherein: The channels (12a, 12b) have at least two outlets (13) per channel (12a, 12b).

3. The continuous casting apparatus according to claim 2, wherein: The axis of the outlet (13) of the channel (12a, 12b) is positioned toward a corner of the crystallizer (3).

4. The continuous casting apparatus according to claim 1, wherein: The composite metal product is a slab, and wherein the axis of the outlet (13) of the channel is positioned towards the narrow face of the crystalliser (3).

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

6. A continuous casting apparatus according to any one of the preceding claims, wherein: The dome also includes a support arm (7).

7. A method of continuously casting a composite metal product using the continuous casting apparatus according to any one of the preceding claims, the composite metal product having different shells (16a, 16b) and a body (17), wherein: The shell (16a, 16b) is divided into two parts having different compositions than the composition of the body (17), wherein: - injecting liquid metal into a tundish (2) located above the continuous casting nozzle (1), - the liquid metal flows from the tundish (2) into the upper part (4) of the casting nozzle (1), thereby forming an initial flow, - the initial flow impinges on the dome (6), thereby dividing the initial flow into at least two separate flows, - the separated flow flows into the chamber (9a, 9b) of the nozzle (1), - injecting a powder into at least one of said chambers (9a, 9b) and mixing said powder with the liquid metal flow flowing into said chambers (9a, 9b), thereby changing the composition of the liquid metal flow, - the separated flows are then distributed into the channels (12a, 12b) of the lower part of the continuous casting nozzle (1), - injecting the liquid metal into the crystallizer (3), wherein the liquid metal flowing in one channel (12b, 12c) is injected into the left part of the crystallizer (3) through at least one outlet (13), and the liquid metal flowing into the other channel (12a) is injected into the right part of the crystallizer through at least one outlet (13) of each channel.

8. The method according to claim 7, wherein: The liquid metal is steel.

9. The method according to claim 7 or 8, wherein The upstream part (14) of the crystallizer (3) contains two liquid metals of different compositions in two parts.

10. The method according to claim 9, wherein: The composition of the liquid metal in the left portion of the upstream portion (14) of the crystallizer (3) is formed only by the base metal from the tundish (2), and the composition of the liquid metal in the right portion of the upstream portion (14) of the crystallizer (3) is formed by the base metal from the tundish (2) mixed with the powder injected under the dome (6).

11. The method according to claim 9, wherein The composition of the liquid metal in the left portion of the upstream portion (14) of the crystallizer (3) is a mixture of base metal from the tundish (2) and one type of powder injected below the dome (6), and the composition of the liquid metal in the right portion of the upstream portion (14) of the crystallizer (3) is a mixture of base metal from the tundish (2) and another type of powder injected below the dome (6).

12. The method according to claims 9 to 11, wherein: The downstream portion (15) of the crystallizer (3) contains liquid metal whose composition is a mixture of the compositions of the two portions coming from the upstream portion (14) of the crystallizer (3).

13. A composite metal blank or composite metal ingot having different shells (16a, 16b) and a main body (17), wherein: The shell (16a, 16b) is divided into two parts having different compositions from the composition of the body (17).

14. A composite metal sheet blank having different outer shells (16a, 16b) and a main body (17), wherein: The shell (16a, 16b) is divided into two parts having different compositions from the composition of the body (17).

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