Continuous casting equipment

Abstract

The present invention relates to a continuous casting nozzle for manufacturing composite metal products having separate shells and bulk, wherein the shell is separated into two parts having different compositions, the composition of which differs from the composition of the bulk, and the nozzle comprises: - a dome having means for dividing an initial flow of liquid metal into at least two separate flows; - an inner wall located below the dome and forming at least two chambers; - means for injecting powder through the dome to allow mixing with the liquid metal; and - a lower part comprising at least two channels, extending from the upper part into the mold and opening into the mold by at least one lateral outlet for each channel. The present invention also relates to a method of continuous casting and related products using a continuous casting nozzle relating to the present invention.

Description

Technical Field

[0001] The present invention relates to continuous casting equipment. In particular, the present invention relates to a continuous casting nozzle with an improved design made for manufacturing composite metal products.

Background Art

[0002] Composite metal materials are a well-known product category. Their specificity lies in their ability to associate different mechanical properties due to their structure consisting of different metals with different compositions. Clad steel is an example of a composite metal material having a bulk composed of a specific type of metal and a surface or shell composed of one or two other types of metals.

[0003] However, these products are mainly manufactured using batch processes. There are very few manufacturing methods using continuous processes.

[0004] European Patent Application No. 3804874 describes an apparatus and method for the continuous production of clad metal strips. The method uses a metal coil as the base metal and includes the step of continuous casting using two different tundishes to add different metal layers on the surface of the metal, using different apparatus and process steps. This method enables the continuous production of composite metal products having a bulk formed from one metal composition and a shell composed of one or two other metal compositions.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the solutions proposed in the prior art involve too many steps and associated equipment, making them difficult to implement in industrial settings.

[0007] This invention discloses a continuous casting nozzle for manufacturing composite metal products having three different metal compositions, which have sufficient stability to obtain high-quality products, using simple equipment. [Means for solving the problem]

[0008] A first object of the present invention is a continuous casting apparatus comprising a nozzle 1, a tundish 2, and a mold 3 for manufacturing a composite metal product having separate shells 16a, 16b and a bulk 17, wherein the shells 16a, 16b are separated into two parts having different compositions, the composition of which differs from the composition of the bulk 17, the nozzle 1 is located between the tundish 2 and the mold 3, and the nozzle 1 is - The upper portion 4 is positioned downstream of the tundish 2 with respect to the direction of movement of the liquid metal, - A dome 6 positioned at the inlet of the upper portion 4, wherein the dome 6 includes means for dividing the initial flow of liquid metal into at least two separate flows, - An inner wall 8 located below the dome 6 and forming at least two chambers 9a, 9b, wherein the separate flows of liquid metal flow through each of the chambers 9a, 9b, the inner wall 8, -Means 10 for injecting powder into at least one of the chambers 9a and 9b via the dome 6 in order to enable mixing with the liquid metal flowing into the chambers 9a and 9b, - A lower portion 5 comprising at least two channels 12a, 12b, extending from the upper portion 4 into the mold 3, and opening into the mold 3 by at least one lateral outlet 13 for each channel 12a, 12b, wherein one of the channels is connected to one chamber 9a, 9b, allowing liquid metal to flow into the left portion of the mold 3 through the channel, and the other channel is connected to the other chamber 9a, 9b, allowing liquid metal to flow into the right portion of the mold 3 through the channel, and It is equipped with.

[0009] The continuous casting apparatus according to the present invention may also have the following optional features, which may be considered individually or in combination: -Channels 12a and 12b each have at least two outlets, - The exit 13 is positioned so that its axes face the corners of the mold 3. - The composite metal product is a slab, and the exit 13 is positioned so that their axes face the narrow surface of the mold 3. - The dome 6 further comprises means 11 for injecting gas through the dome 6, - The dome is further equipped with support arms 7.

[0010] A second object of the present invention is a method for continuously casting a composite metal product having individual shells 16a, 16b and a bulk 17 using the continuous casting apparatus described in the above claims, wherein the shells 16a, 16b are separated into two parts having different compositions, and the composition of the shells is different from the composition of the bulk 17. -Liquid metal is poured into the tundish 2 located above the continuous casting nozzle 1. -The liquid metal flows from the tundish 2 into the upper portion 4 of the casting nozzle 1 to form an initial flow. -The initial flow collides with the dome 6, thereby separating the initial flow into at least two separate flows. -The aforementioned separate flows into the chambers 9a and 9b of nozzle 1, -The powder is injected into at least one of the chambers 9a and 9b and mixed with the flow of liquid metal into the chambers 9a and 9b, thereby altering its composition. -Then, the separate flows are distributed to channels 12a and 12b in the lower part of the continuous casting nozzle 1. - The liquid metal is poured into the mold 3, and the liquid metal flowing into one channel 12b, 12c is poured into the left portion of the mold 3 by at least one outlet 13, and the liquid metal flowing into the other channel 12a is poured into the other portion of the mold by at least one outlet 13 for each channel.

[0011] The continuous casting method according to the present invention may also have the following optional features, which may be considered individually or in combination: -The liquid metal is steel, - The upstream portion 14 of the mold 3 contains two liquid metals of different compositions in two separate parts. - The composition of the liquid metal in the left portion of the upstream section 14 of mold 3 is made from base metal provided by the tundish 2, and the composition of the liquid metal in the right portion of the upstream section 14 of mold 3 is made from a mixture of powder injected below the dome 6 and base metal provided by the tundish 2. -The composition of the liquid metal in the left portion of the upstream section 14 of the mold 3 is made from a base metal provided by the tundish 2, which is mixed with a certain type of powder injected below the dome 6, and the composition of the liquid metal in the right portion of the upstream section 14 of the mold 3 is made from a mixture of the base metal provided by the tundish 2 and another type of powder injected below the dome 6. - The downstream portion 15 of the mold 3 contains liquid metal with a composition resulting from the mixing of compositions brought about by the two portions of the upstream portion 14 of the mold 3.

[0012] A third object of the present invention is a composite metal billet or bloom having separate shells 16a, 16b and a bulk 17, wherein the shells 16a, 16b are separated into two parts having different compositions, the compositions of which are different from the composition of the bulk 17.

[0013] A fourth object of the present invention is a composite metal slab having individual shells 16a, 16b and a bulk 17, wherein the shells 16a, 16b are separated into two parts having different compositions, and the compositions are different from the composition of the bulk 17.

[0014] The present invention will be described non - limitatively with reference to the following drawings.

Brief Description of the Drawings

[0015] [Figure 1] Overall view of the nozzle according to the present invention in the usage form. [Figure 2] Dome viewed from above. [Figure 3] Cross - sectional view A - A of the upper part of the nozzle below the dome of FIG. 1. [Figure 4] Cross - sectional view B - B of the mold and the nozzle showing the flow in a billet or bloom type product. [Figure 5] Cross - sectional view B - B of the mold and the nozzle showing the flow in a slab type product. [Figure 6] Immersion part of the nozzle showing the composition and flow in the mold. [Figure 7] Cross - section of a composite metal billet or bloom obtained by continuous casting using the present invention. [Figure 8] Cross - section of a composite metal slab obtained by continuous casting using the present invention.

Embodiments for Carrying Out the Invention

[0016] In the following description, claims, and figures, directional terms are defined using the X, Y, and Z coordinates as reference, where Z is the direction of liquid metal flow, X is the direction parallel to the long plane of the mold, and Y is the direction parallel to the narrow plane of the mold. The references are shown in each equipment diagram. When a diagram is a 2D planar view, axes outside the diagram are represented, according to established convention, by a dot in a circle when it is facing the reader, and by a cross in a circle when it is facing away from the reader. In particular, terms such as "top," "upper," "upstream," "ascending," "above," "bottom," "lower," "below," "downstream," and "descending" are defined according to the Z axis. The terms "left" and "right" are defined according to the X axis.

[0017] The objective of this invention is to cast composite metal products.

[0018] Figure 1 shows a nozzle 1 positioned between the tundish 2 and the mold 3. The nozzle 1 consists of an upper part 4 and a lower part 5.

[0019] The dome 6 is positioned at the entrance of the upper section 4 and partially closes it. The upper end of the dome 6 preferably has an inclination at a specific angle, for example, greater than 15°. The dome 6 also has sides, which preferably form sharp edges with inclinations. The dome 6 is secured to the upper section 4 by one or more support arms 7.

[0020] The inner wall 8 located below the dome 6 forms at least two chambers 9a and 9b in the upper portion 4. In the configuration shown in Figure 1, there are two chambers 9a and 9b.

[0021] Means 10 for injecting powder and means 11 for injecting gas are also provided in the upper portion 4, each means partially located on one of the support arms 7 and penetrating the dome 6. Means 10 for injecting powder can be, for example, an endless screw connected to a powder tank.

[0022] Figure 2 shows a configuration of dome 6 having four support arms 7, with one passage for a powder injection device 10 located on one of the support arms 7, and three passages for gas injection devices 11 located on the other three support arms 7. Another configuration, not shown, has two passages for two powder injection devices 10 located on two opposing support arms 7.

[0023] The dome 6 may also have other configurations with fewer or more support arms 7. For example, a configuration with two or three support arms 7 can be considered.

[0024] As shown in Figure 1, the lower portion 5 of the nozzle 1 consists of two channels 12a and 12b that extend from the chambers 9a and 9b of the upper portion 4 and terminate into the mold 3. The channels 12a and 12b open into the mold 3 by at least one lateral outlet 13 for each channel 12a and 12b.

[0025] The number and configuration of the outlets 13 depend on the type of cast product. For billet or bloom-type products, it is preferable that the mold 3 has a square cross-section and therefore has at least two outlets 13 for each channel 12a, 12b, with their axes positioned toward the corners of the mold 3. For slab-type products, it is preferable that the mold 3 has a rectangular cross-section and therefore has at least one outlet 13 for each channel 12a, 12b, with their axes positioned toward the narrow faces of the mold 3. Two described configurations of the outlets 13 depending on the product type are shown in Figures 4 and 5, which are top views of the nozzle 1 and the bottom of the mold 3. Figure 4 is a diagram of the nozzle 1 in the mold 3 for a billet or bloom-type product, and Figure 5 is a diagram of the nozzle 1 in the mold 3 for a slab-type product.

[0026] In this embodiment, channels 12a and 12b are circular. In a preferred embodiment, channels 12a and 12b have a semi-elliptical cross-section.

[0027] Figure 3 shows a cross-sectional view AA of nozzle 1 in the configuration described in Figure 1. Figure 2 is positioned in the same orientation as Figure 3. Figure 2 can be superimposed on Figure 3 to have a cross-sectional view of nozzle 1 above dome 6.

[0028] As shown in Figure 3, the inner wall 8 forms two chambers 9a and 9b having the same volume. Each chamber 9a and 9b is connected to its respective channel 12a and 12b.

[0029] In other configurations, the inner wall 8 has different shapes and forms different numbers of chambers. For example, in a cross-sectional view, a Y-shape can form three chambers, or a V-shape can form two chambers with different volumes.

[0030] An embodiment of the present invention in use is shown in Figure 1, and therefore its use will be described with reference to Figure 1.

[0031] Liquid metal of a predetermined 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 is described accordingly. 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.

[0032] The dome 6 is positioned within the steel track and collides with the initial flow. The inclination of the dome 6 causes the steel to flow toward its edge. The support arms 7 form different regions on the dome 6, dividing the steel into multiple separate flows. The number of separate flows is determined by the configuration of the dome 6 and its support arms 7. In this particular embodiment, there are four separate flows.

[0033] The separated flows then flow into different chambers 9a and 9b. In this configuration, half of the flow flows into one chamber 9a and the other half flows into the other chamber 9b. The powder is injected simultaneously into at least one of chambers 9a and 9b. The configuration of chambers 9a and 9b slows down the steel, allowing it to accumulate within the chambers 9a and 9b. As a result, the powder can be efficiently mixed with the steel within the chambers 9a and 9b to alter the steel's composition and initiate melting.

[0034] Another configuration, not shown, uses two powder injectors 10 to add different powders to two chambers 9a and 9b.

[0035] The powder injected into the steel can have a variety of compositions, such as FeSi, Ni, FeAl, FeTi, FeCr, FeNb, FeB, FeCe, FeMo, etc.

[0036] The injection of powder is facilitated by a gas injection device 11 that forms a gas flow. The gas injection device 11 generates a gas flow that causes the steel to flow outwards from the upper portion 4 of the nozzle 1 and downwards from the dome 6, thus forming a zone without steel below the dome 6. This hollow zone prevents contact between the steel and the powder injection device 10 and thus avoids potential clogging of the powder injection device 10.

[0037] The gas is preferably non-oxidizing argon, for example, to prevent it from reacting with the steel during casting.

[0038] After injection, the two chambers 9a and 9b house two types of steel with different compositions.

[0039] Next, the steel flows into channels 12a and 12b in the lower part 5 of the nozzle 1. Then, the steel is poured into the mold 3 through the outlets 13 of channels 12a and 12b.

[0040] The configuration of channels 12a, 12b and outlet 13 allows steel supplied by one chamber 12a to be poured into the left portion of the mold 3, and steel supplied by the other chamber 12b to be poured into the right portion of the mold 3.

[0041] Figure 6 shows the immersion portion of nozzle 1 and mold 3, and highlights the different compositions of steel formed within mold 3. The upstream portion 14 of mold 3 consists of two different steels poured in through two channels 12a and 12b located on its left and right sides. The flow of liquid metal entering from each outlet 13 splits into an upward flow 19 and a downward flow 20. The downward flow terminates in a vortex, thus causing remixing inside the mold.

[0042] In the first embodiment, when there is only one powder injection device 10, the composition of the liquid metal in the left portion is made from the base metal provided by the tundish 2, and the composition of the liquid metal in the right portion is made from a mixture of powder injected below the dome 6 and the base metal provided by the tundish 2.

[0043] In another embodiment, if there are two powder injectors 10, the composition of the liquid metal in the left portion is made from a base metal provided by the tundish 2, which is mixed with one type of injected powder, and the composition of the liquid metal in the right portion is made from a mixture of the other type of injected powder and the base metal provided by the tundish 2.

[0044] As the liquid metal flows into the mold, remixing occurs, forming a third composition in the downstream portion 15 of the mold 3, which is derived from the mixing of the compositions brought about by the two portions of the upstream portion 14 of the mold 3.

[0045] In mold 3, the steel in the upstream section 14 solidifies first, thereby forming the shells 16a and 16b. The steel in the downstream section 15 then solidifies inside the shells 16a and 16b, thereby forming the bulk material 17. After complete solidification, the resulting material is a composite metal product having separate shells 16a, 16b and bulk material 17. Its shells 16a and 16b are separated into two parts having different compositions, and its bulk material 17 has a different composition from the two compositions of shells 16a and 16b. Thus, the cast product can have different properties in its two parts, shells 16a and 16b.

[0046] Two types of products from the two preferred embodiments are shown in Figure 7 for billet or bloom type products and in Figure 8 for slab type products.

[0047] In a preferred embodiment, the nozzle 1 is mainly composed of a fire-resistant material surrounded by a metal ring.

[0048] In its intended use, the continuous casting nozzle 1 meets expectations in terms of stability. This enables a stable casting speed, and the different flow of liquid metal allows for greater stability in different areas of the mold 3. This stability results in high-quality semi-finished products with a clear compositional gradient between its two shell parts 16a and 16b and its bulk 17.

Claims

1. A continuous casting apparatus comprising a nozzle (1), a tundish (2), and a mold (3) for manufacturing a composite metal product having individual shells (16a, 16b) and a bulk (17), wherein the shells (16a, 16b) are separated into two parts having different compositions, the composition of which differs from the composition of the bulk (17), the nozzle (1) is located between the tundish (2) and the mold (3), and the nozzle (1) is, - The upper portion (4) is positioned downstream of the tundish (2) with respect to the direction of movement of the liquid metal, - A dome (6) positioned at the inlet of the upper portion (4), wherein the dome (6) comprises means for dividing the initial flow of liquid metal into at least two separate flows, - An inner wall (8) located below the dome (6) and forming at least two chambers (9a, 9b), wherein the separate flows of liquid metal each flow into each of the chambers (9a, 9b), - Means (10) for injecting powder into at least one of the chambers (9a, 9b) via the dome (6) in order to enable mixing with the liquid metal flowing into the chambers (9a, 9b), - A lower portion (5) comprising at least two channels (12a, 12b), extending from the upper portion (4) into the mold (3), and opening into the mold (3) through at least one lateral outlet (13) for each channel (12a, 12b), wherein one of the channels is connected to one chamber (9a, 9b), allowing liquid metal to flow into the left portion of the mold (3), and the other channel is connected to the other chamber (9a, 9b), allowing liquid metal to flow into the right portion of the mold (3), and A continuous casting machine equipped with the following features.

2. The continuous casting apparatus according to claim 1, wherein each channel (12a, 12b) has at least two outlets (13).

3. The continuous casting apparatus according to claim 2, wherein the outlets (13) of the channels (12a, 12b) are positioned so that their axes face the corners of the mold (3).

4. The continuous casting apparatus according to claim 1, wherein the composite metal product is a slab, and the outlet (13) of the channel is positioned such that its axis faces the narrow surface of the mold (3).

5. The continuous casting apparatus according to any one of claims 1 to 4, wherein the dome (6) further comprises means (11) for injecting gas through the dome (6).

6. The continuous casting apparatus according to any one of claims 1 to 5, wherein the dome further comprises a support arm (7).

7. A method for continuously casting a composite metal product having individual shells (16a, 16b) and a bulk (17) using a continuous casting apparatus according to any one of claims 1 to 6, wherein the shells (16a, 16b) are separated into two parts having different compositions, and the composition of the shells differs from the composition of the bulk (17), - Liquid metal is poured 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) to form an initial flow. - The initial flow collides with the dome (6), thereby separating the initial flow into at least two separate flows. - The separate flows mentioned above enter the chambers (9a, 9b) of the nozzle (1), - The powder is injected into at least one of the chambers (9a, 9b) and mixed with the flow of liquid metal into the chambers (9a, 9b), thereby altering its composition. -Then the separate flows are distributed to the channels (12a, 12b) in the lower part of the continuous casting nozzle (1), - The liquid metal is poured into the mold (3), and the liquid metal flowing into one channel (12b, 12c) is poured into the left portion of the mold (3) by at least one outlet (13), and the liquid metal flowing into the other channel (12a) is poured into the right portion of the mold by at least one outlet (13) for each channel. method.

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 portion (14) of the mold (3) contains two liquid metals of different compositions in two separate portions.

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 mold (3) is made from base metal provided by the tundish (2), and the composition of the liquid metal in the right portion of the upstream portion (14) of the mold (3) is made from a mixture of powder injected below the dome (6) and base metal provided by the tundish (2).

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 mold (3) is made from a base metal provided by a tundish (2) that is mixed with a certain 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 mold (3) is made from a base metal provided by a tundish (2) that is mixed with another type of powder injected below the dome (6).

12. The method according to any one of claims 9 to 11, wherein the downstream portion (15) of the mold (3) contains a liquid metal having a composition resulting from a mixture of compositions brought about by the two portions of the upstream portion (14) of the mold (3).

13. A composite metal billet or bloom having separate shells (16a, 16b) and a bulk (17), wherein the shells (16a, 16b) are separated into two parts having different compositions, the composition of which is different from the composition of the bulk (17).

14. A composite metal slab having separate shells (16a, 16b) and a bulk (17), wherein the shells (16a, 16b) are separated into two parts having different compositions, the composition of which is different from the composition of the bulk (17).

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