EP4215296A1 - Broadside mould plate, continuous casting mould and method for producing a broadside mould plate - Google Patents

Abstract

The invention relates to a broadside mold plate (1) for a continuous casting mold, having a contact surface (2) for contacting a cast strand cast in the continuous casting mold, a depression (3) being formed in the contact surface (2) which, with respect to a width direction of the contact surface (2 ) is arranged in a central region of the contact surface (2) and has a depth (T) which increases continuously in the direction of an upper edge (4) of the contact surface (2) on the mold inlet side, the depression (3) being in the width direction of the contact surface ( 2) transitions on both sides, preferably continuously differentiable, into a planar surface section (5, 6) of the contact surface (2), the surface sections (5, 6) being arranged in a common plane. In order to minimize mechanical stresses in the strand shell of the cast strand within the continuous casting mold, the recess (3) has a constant width (B) over its height (L), is between the lower end of the recess (3) and the lower edge ( 7) of the contact surface (2), another flat surface section (8) of the contact surface (2) is arranged, which lies in the common plane, and the depression (3) goes in the height direction z of the contact surface (2) in an at least continuous lower transition the further lower surface section (8) over.

Description

The invention relates to a wide-side mold plate for a continuous casting mold, having a contact surface for contacting a molten metal poured into the continuous casting mold and a cast strand resulting from it, wherein a depression is formed on the contact surface, which is arranged in a central region of the contact surface with respect to a width direction of the contact surface and has a depth that increases continuously in the direction of an upper edge of the contact surface on the mold entry side, the depression in the width direction of the contact surface being continuously differentiable on both sides into a planar one Surface section of the contact surface merges, the surface sections being arranged in a common plane.

In addition, the invention relates to a continuous casting mold, in particular a thin slab continuous casting mold.

Furthermore, the invention relates to a method for producing a wide side mold plate for a continuous casting mold, wherein the wide side mold plate is produced with a contact surface for contacting a molten metal poured into the continuous casting mold and a cast strand resulting from it, wherein a depression is formed on the contact surface, which is arranged in a width direction of the contact surface in a central region of the contact surface and has a depth that increases continuously in the direction of an upper edge of the contact surface on the mold inlet side, the depression being formed in such a way that they can be continuously differentiated into one on both sides in the width direction of the contact surface flat surface section of the contact surface merges, the surface sections being arranged in a common plane.

CN 101 412 080 A discloses a continuous casting mold having a sprue whose width progressively decreases from an entrance of the continuous casting mold.

DE 39 07 351 A1 relates to a mold with a pouring funnel, wherein a contour of an inner wall of the pouring funnel in the direction of passage of the strand is designed in such a way that its radii gradually becoming larger in the direction of passage of the strand merge into the contour of the inner wall of the mold.

EP 0 149 734 A2 relates to a mold for the continuous casting of steel strip. The mold has cooled broad side walls and narrow side walls, the broad side walls forming a funnel-shaped pouring area which is reduced to the narrow side walls and in the direction of casting to the format of the cast strip. The wide side walls run parallel to the side of the pouring area at a distance corresponding to the strip thickness up to the respective narrow side wall.

EP 0 909 597 A1 discloses a surface contour for a broadside mold plate having a central depression that extends the full height of the broadside mold plate and continues further into an underlying segment.

EP 1 002 599 A1 relates to a permanent mold for the continuous casting of metal, which has a pouring area which has cooled broad side walls and narrow side walls and tapers in the shape of a funnel in the pouring direction to the format of the cast strand. For the purpose of creating areas of reduced deformation, the distance between the lateral edges of the funnel area as well as between the lines delineating the domed areas is more opposite Define curvature or flat surfaces of different inclinations, changeable in any way over one or more height sections of the funnel area.

Existing broad side mold plates therefore generally have a pouring funnel shape which has a combination of radii on the upper mold entry side of a broad side mold plate or the contour of which changes continuously over the height of the broad side mold plate. As described above, it is also known to continue the pouring funnel up to the mold exit side of a wide side mold plate and beyond that into the rollers of a strand guide. At the reversal points of the pouring funnel indentation of a broadside mold plate, stress peaks occur in a newly formed strand shell due to the reversal of the direction of curvature, which can lead to cracks in the continuously cast product, i.e. the cast strand.

One object of the invention is to further develop a known broadside mold plate, a known continuous casting mold and a method for producing a continuous casting mold such that mechanical stress peaks and a mechanical stress level in the strand shell of a cast strand produced are minimized.

This object is solved by the independent patent claims. Advantageous configurations are presented in the following description, the dependent patent claims and the figures, whereby these configurations, taken individually or in combination of at least two of these configurations with one another, can represent a further developing, in particular also preferred or advantageous, aspect of the invention. Configurations of the wide-side mold plate can correspond to configurations of the method and vice versa, even if this is not explicitly referred to in the following in individual cases.

A wide-side mold plate according to the invention for a continuous casting mold has a contact surface for contacting a molten metal poured into the continuous casting mold and a cast strand resulting from it, with a depression being formed on the contact surface, which is arranged in a central region of the contact surface with respect to a width direction of the contact surface and has a depth which increases continuously in the direction of an upper edge of the contact surface on the mold entry side, the depression in the width direction of the contact surface on both sides being at least continuously, preferably continuously differentiable into a flat formed surface section of the contact surface, with the surface sections being arranged in a common plane, with the depression having a constant width over its height, with a further flat lower surface section of the contact surface being arranged between the lower end of the depression and the lower edge of the contact surface on the mold outlet side, and with the depression in the height direction of the contact surface merging into the further lower surface section in an at least continuous lower transition.

The invention proposes a broadside mold plate, for example a broadside mold copper plate, in which the indentation of constant width in the vertical direction leads continuously to the upper edge of the further flat (lower) surface section and there in the lower transition at least continuously merges into the further flat surface section of the contact surface. Due to the at least constant formation of the lower transition between the depression and the further flat lower surface section of the contact surface, a very low-stress deflection of the strand shell of the cast strand from a funnel area of the continuous casting mold formed by the depression into the vertical takes place in the lower transition. The vertical line is formed by the three plane-parallel, flat surface sections of the two opposing broadside mold plates the continuous casting mold. The at least continuous, preferably continuously differentiable transitions between the depression and the two flat surface sections of the contact surface adjacent to the depression in the horizontal direction on the right and left also enable the strand shell of the cast strand to be guided with low stress in the vertical direction. Due to all of the at least constant transitions mentioned, mechanical stress peaks and the mechanical stress level in the strand shell of the cast strand are significantly reduced overall within the continuous casting mold. Therefore, using the broadside mold plate according to the invention, cast strands can be produced with significantly fewer cracks in the strand shell, particularly in a critical area in this respect during immersion pouring within the continuous casting mold. This stress-minimized shaping of the wide-side mold plate according to the invention advantageously allows a higher casting speed, in particular with a small remaining wall thickness of the wide-side mold plate.

The term "at least continuous" means that a corresponding transition can have edges in the form of kinks, but is formed "at least without stair-like cracks or steps" in the surface. Continuity is a prerequisite for continuous differentiability. In this respect, the term "at least continuously" also includes continuous differentiability.

The terms "bottom", "top", "right", "left", "vertical" and "horizontal" refer to the representation and arrangement of the broadside mold plate in the figures.

The terms "lower end" of the depression, "lower transition" of the depression into the lower surface section are used synonymously. The term "transition zone" means a special embodiment of this "lower transition", which in this case is smooth, ie continuously differentiable.

The contact surface of the wide-side mold plate according to the invention thus has the plane-parallel flat surface sections and the recess, which is bordered by the flat surface sections except for its upper edge on the edge of the contact surface on the mold inlet side. A molten metal poured into the continuous casting mold using an immersion casting process, for example, is progressively cooled as it moves from top to bottom in the mold through contact with the broadside mold plate, whereby a strand shell or a cast strand is formed, which is guided along the broadside mold plate before it emerges from the continuous casting mold.

Surprisingly, it has been shown that the inventive design of the depression with a constant width over its height, the lower height of the depression than the height of the wide side mold plate and the at least constant lower transition between the depression and the further flat lower surface section of the contact surface can significantly reduce the introduction of mechanical stresses into the forming or formed strand shell of the cast strand compared to the use of conventional wide side mold plates.

According to an advantageous embodiment, the curvature contour of the surface of the depression of the wide-side mold plate is defined by a surface function y(x,z), as is described below in the exemplary embodiments. According to this, the contour of the indentation or the indentation itself is described, among other things, by the graph of a periodic mathematical function in which the function values are repeated at regular intervals. However, the surface function only describes the lower transition between the depression and the lower surface section as continuous.

An even more significant reduction in the stresses, particularly in the cast strand, can be achieved in that the lower transition of the depression is designed in the form of a transition zone with an upper one boundary between the depression and the transition zone and a lower boundary between the transition zone and the further lower surface section. The transition zone itself, the upper and/or the lower boundary are then each designed to be continuously differentiable. In this case, the transition zone, the upper limit and/or the lower limit can be defined or realized by variable radii or by a function of the nth degree. Within the scope of the invention, a continuously differentiable boundary is to be understood as meaning a smooth transition or a smooth (upper) surface without surface cracks, edges, kinks or the like.

The above-mentioned object of the invention is also achieved by a continuous casting mold according to the invention, in particular a thin slab continuous casting mold according to claim 4 . It has two opposite broad side mold plates, of which at least one broad side mold plate is designed according to one of the configurations mentioned above.

The advantages mentioned above in relation to the broadside mold plate are correspondingly associated with the continuous casting mold. The continuous casting mold can also have two corresponding, in particular identically designed, broadside mold plates.

Finally, the above-mentioned object is also achieved by a method according to the invention for producing a wide-side mold plate for a continuous casting mold according to claim 5 . The advantages mentioned above in relation to the wide-side mold plate are correspondingly associated with the method. In particular, the wide side mold plate can be produced according to one of the configurations mentioned above using the method.

Figur 1:

eine schematische und perspektivische Darstellung eines Ausführungsbeispiels für eine erfindungsgemäße Breitseitenkokillenplatte; und

Figur 2:

eine weitere schematische und perspektivische Darstellung der in Figur 1 gezeigten Breitseitenkokillenplatte.

In the following, the invention is explained by way of example with reference to the attached figures using a preferred embodiment, with the features explained below both taken individually and in Combination of at least two of these features together can represent an advantageous or further aspect of the invention. It shows:

Figure 1:

a schematic and perspective view of an embodiment of a broad side mold plate according to the invention; and

Figure 2:

a further schematic and perspective view of the in figure 1 broadside mold plate shown.

Identical or functionally identical components are provided with the same reference symbols in the figures. Repeated description of such components may be omitted to avoid unnecessary repetition in detail.

figure 1 shows a schematic and perspective representation of an exemplary embodiment of a wide-side mold plate 1 according to the invention, obliquely from above, for a continuous casting mold (not shown).

The broad side mold plate 1 has a contact surface 2 for contacting a molten metal (not shown) poured into the continuous casting mold and a cast strand (not shown) resulting therefrom.

A depression 3 is formed on the contact surface 2, which is arranged in a central area of the contact surface 2 with respect to a width direction of the contact surface 2 and has a depth T that continuously increases in the direction of an upper edge 4 of the contact surface 2 on the mold entry side. In the width direction of the contact surface 2 , the indentation 3 merges on both sides into a planar surface section 5 or 6 of the contact surface 2 in a continuously differentiable manner. The two surface sections 5 and 6 are arranged in a common plane.

The depression 3 has a constant width B over its height L. FIG. A further flat surface section 8 of the contact surface 2 is arranged between a lower edge 7 of the contact surface 2 on the mold outlet side and the depression 3 , which is arranged in the common plane of the flat surface sections 5 and 6 . In the height direction z of the contact surface 2 , the depression 3 merges into the further surface section 8 in a continuously differentiable manner.

wobei

• die Konstante α sich bewegt in einem Definitionsbereich von α = [ 0 ...0,3 ];
• die Konstante β definiert ist in einem Wertebereich von β = [0,015...0,025] 1/mm;
• die Konstante y definiert ist in einem Wertebereich von y = [0,001 ... 0,004] 1/mm;
• die Konstante δ sich bewegt in einem Wertebereich von δ = [0...60] mm;
• die Konstante Ω sich bewegt in einem Wertebereich von Ω = [0...0,1] 1/mm;
• die Variable x sich erstreckt zwischen [-900...900]; und
• die Höhenvariable z sich bewegt zischen [0...950].

The curvature contour of the surface of the recess 3 is defined by the area function: $$\mathrm{y}\left(\mathrm{x},\mathrm{e.g}\right)=\left(\mathrm{a}*\sin \left(\mathrm{\beta }*\mathrm{x}\right)-\mathrm{g}*\mathrm{x}+1\right)*\mathrm{t}\left(\mathrm{e.g}\right)\mathrm{with}\mathrm{t}\left(\mathrm{e.g}\right)=\mathrm{\delta }*\left(1-\mathrm{\Omega }*\mathrm{e.g}\right)$$

whereby

• the constant α moves in a domain of α = [ 0 ...0.3 ];
• the constant β is defined in a value range of β = [0.015...0.025] 1/mm;
• the constant y is defined in a range of values from y = [0.001...0.004] 1/mm;
• the constant δ ranges from δ = [0...60] mm;
• the constant Ω moves in a value range of Ω = [0...0.1] 1/mm;
• the variable x ranges between [-900...900]; and
• the height variable z moves between [0...950].

The coordinates y, x, z span a coordinate system as in figure 1 shown.

The function values of the function y and the depth of the indentation decrease continuously in the z direction until the indentation 3 merges at its lower end into the further flat lower surface section 8 in the lower transition.

The area function y mentioned above only describes this lower transition as continuous. In an advantageous embodiment, however, this lower transition can also be smooth or rounded, ie in the form of a continuously differentiable Transition zone 10 may be formed. A corresponding mathematical description of this smooth transition zone is not described by the area function mentioned above. In the area of the transition zone, the values for the constant y in the function y would then be further reduced. The transition zone 10 would then be delimited by an upper delimitation 12-o between the depression 3 and the transition zone 10 and a lower delimitation 12-u between the transition zone 10 and the further lower surface section 8. The transition zone 10 itself, the upper and/or the lower delimitation 12-o, 12-u would then be continuously differentiable.

mit

B

Breite der Vertiefung 3

L

Höhe der Vertiefung 3

W

die Breite der Breitseitenkokillenplatte; und

H

die Höhe der Breitseitenkokillenplatte

The following applies to the area ratio of the area Y projected from the depression 3 into the plane of the area sections 5, 6 and 8 to the plane-parallel area P: $$\begin{array}{ccc}0.4<=\mathrm{Y}/\mathrm{P}<=0.8& \mathrm{with}& \mathrm{Y}=\mathrm{L}*\mathrm{B}\mathrm{and}\mathrm{P}=\mathrm{W}*\mathrm{H}-\mathrm{Y}\end{array}$$

with

B

width of recess 3

L

height of recess 3

W

the width of the broadside mold plate; and

H

the height of the broad side mold plate

The function Y=L*B describes the projected area only approximately, because it assumes a straight lower limit 12-u of the lower transition. However, in the case of a transition zone 10, the lower boundary is typically curvilinear, as shown in the figures, which is not accounted for by the simple Y function.

figure 2 shows a further schematic and perspective representation of in figure 1 shown wide side mold plate 1 from below diagonally. Contour lines 9 are shown to clarify the shape of the depression 3 . The lower Surface section 10 of the depression 3, i.e. the transition zone, transitions at its upper limit continuously differentiably into the remaining surface section 11 of the depression above it and at its lower limit continuously differentiably into the lower flat surface section 8, with the upper and lower limits of the transition zone 10 being indicated by the curved lines 12-o and 12-u. In the exemplary embodiment shown, the surface section 10 is convexly curved; however, it can also be concavely curved or have a different functional design.

Reference List

1

broad side mold plate

2

contact surface of 1

3

deepening on 2

4

top edge of 2

5

flat surface section of 2

6

flat surface section of 2

7

lower edge of 2

8th

lower flat surface section

9

Contour line from 3

10

Transition zone = area section of 3

11

surface section of 3

12-o

upper boundary of the transition zone

12-u

lower limit of the transition zone

B

width of 3

L

height of 3

T

depth of 3

W

the width of the broad side mold plate

H

the height of the broad side mold plate

Claims (6)

Wide-side mold plate (1) for a continuous casting mold, having a contact surface (2) for contacting a molten metal poured into the continuous casting mold and a cast strand resulting from it, wherein a depression (3) is formed on the contact surface (2), which is arranged in a central area of the contact surface (2) with respect to a width direction of the contact surface (2) and has a depth (T) that is continuous in the direction of an upper edge (4) of the contact surface (2) on the mold entry side enlarged, the indentation (3) in the width direction of the contact surface (2) transitioning at least continuously on both sides, preferably continuously differentiable, into a planar surface section (5, 6) of the contact surface (2), the surface sections (5, 6) being arranged in a common plane, characterized in that that the depression (3) has a constant width (B) over its height (L); that between the lower end of the depression (3) and the lower edge (7) of the contact surface (2) on the mold outlet side, a further lower flat surface section (8) of the contact surface (2) is arranged, which lies in the common plane; and that the indentation (3) merges into the further surface section (8) in the height direction z of the contact surface (2) in an at least continuous lower transition. Wide side mold plate (1) according to claim 1,
characterized, that the curvature contour of the surface of the depression (3) with the continuous lower transition into the lower surface section (8) is defined by the surface function: $$\mathrm{y}\left(\mathrm{x},\mathrm{e.g}\right)=\left(\mathrm{a}*\sin \left(\mathrm{\beta }*\mathrm{x}\right)-\mathrm{g}*\mathrm{x}+1\right)*\mathrm{t}\left(\mathrm{e.g}\right)\mathrm{with}\mathrm{t}\left(\mathrm{e.g}\right)=\mathrm{\delta }*\left(1-\mathrm{\Omega }*\mathrm{e.g}\right)$$

whereby the constant α moves in a domain of α = [ 0 ...0.3 ]; the constant β is defined in a value range of β = [0.015...0.025] 1/mm; the constant y is defined in a range of values from y = [0.001...0.004] 1/mm; the constant δ ranges from δ = [0...60] mm; the constant Ω moves in a value range of Ω = [0...0.1] 1/mm; the variable x ranges between [-900...900]; and the height variable z ranges between [0...950]. Wide side mold plate according to one of the preceding claims, characterized in that The following applies to the area ratio between the area Y projected by the depression and the plane-parallel area P: $$0.4<=\mathrm{Y}/\mathrm{P}<=0.8\mathrm{is}\mathrm{with}\mathrm{Y}=\mathrm{L}*\mathrm{B}\mathrm{and}\mathrm{P}=\mathrm{W}*\mathrm{H}-\mathrm{Y}$$

whereby L the height of the depression; B is the width of the depression; W is the width of the broadside mold plate; and H is the height of the broadside mold plate designated. Wide side mold plate (1) according to one of the preceding claims, characterized in that
that the lower transition is in the form of a transition zone (10) with an upper boundary (12-o) between the depression (3) and the transition zone (10) and a lower boundary (12-u) between the transition zone (10) and the further lower surface section (8); and that the transition zone (10) itself, the upper and/or the lower boundary (12-o, 12-u) are continuously differentiable. Continuous casting mould, in particular thin slab continuous casting mould, with two opposite wide side mold plates (1);
characterized,
that at least one of the wide side mold plates (1) is designed according to one of the preceding claims. Method for producing a wide side mold plate (1) for a continuous casting mold,
characterized,
that the wide side mold plate (1) is formed according to one of claims 1 to 4.

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