Stranggießkokille

Abstract

Continuous casting mold (1) comprising a number of mold walls (2, 3) whose inner surfaces (4) form a casting surface, wherein at least one of the inner surfaces (4) is provided with a profile (5) such that the inner surface (4) has a non-planar shape, wherein the inner surface (4) provided with the profile (5) has a central area (6) extending over the height (L) and over at least half the width (S) of the inner surface (4), wherein the surface of the inner surface (4) in the side areas (7) of the inner surface (4) adjoining the central area (6) is offset at least sectionally in the direction normal (y) to the mold wall (2, 3) relative to the surface of the inner surface (4) in the central area (6), wherein the offset (8) changes over the height (z) of the continuous casting mold (1) and wherein the offset (8) is greater in the upper area of ​​the continuous casting mold (1) than in the lower area of ​​the continuous casting mold (1), characterized in thatthat the offset (8) is formed by sections raised and recessed in the direction normal (y) to the mold wall (2, 3) relative to the central area (6), wherein the offset (8) is raised above the level of the central area (6) in the upper area of ​​the continuous casting mold (1), in particular in the upper quarter of the height of the continuous casting mold (1), and is recessed relative to the level of the central area (6) in the lower area of ​​the continuous casting mold (1), in particular in the lower quarter of the height of the continuous casting mold (1).

Description

[0001] The invention relates to a continuous casting mold, comprising a number of mold walls which form a casting surface with their inner sides, wherein at least one of the inner sides is provided with a profiling so that the inner side has a non-planar shape, wherein the inner side provided with the profiling has a central region which extends over the height and over at least half the width of the inner side, wherein the surface of the inner side in the side regions of the inner side adjoining the central region is offset at least in sections in the direction normal to the mold wall compared to the surface of the inner side in the central region, wherein the offset changes over the height of the continuous casting mold and wherein the offset is greater in the upper region of the continuous casting mold than in the lower region of the continuous casting mold.

[0002] A wide variety of designs for continuous casting molds are known in the state of the art. Numerous efforts have already been made to modify the surface topography of the mold wall in order to achieve an improved casting pattern.

[0003] A continuous casting mold of this type is disclosed in WO 96 / 35532 A1. Similar solutions are shown in EP 0 179 364 B1, DE 26 26 223 A1, EP 0 931 608 A1, and CN 102 328 037 A.

[0004] WO 99 / 12675 A1 shows a continuous casting mold having narrow mold walls that are convex over a central area; in the edge area, the surface protrudes like a point from the basic geometry of the wall.

[0005] Various other solutions are shown in EP 0 875 312 A1, EP 0 958 871 B1, WO 96 / 33034 A1, DE 41 38 642 A1, DE 35 01 422 C2, WO 2011 / 039083 A1, EP 0 179 364 B1, DE 10 2007 054 911 A1 and JP 56 041051 A.

[0006] The goal of the various known mold wall designs is usually to minimize the risk of edge cracks in the product. Despite the various known solutions, it remains problematic that cracks near the edges of the slab occur relatively easily.

[0007] On the other hand, the unavoidable wear of the mold and its copper plates is relatively high, resulting in correspondingly short mold service life. This wear, i.e., abrasion of the copper side walls, also leads to contamination of the slab surface with copper particles, which causes quality problems. The increasing wear of the narrow-side copper plates at the mold exit is particularly problematic.

[0008] The invention is therefore based on the object of proposing a continuous casting mold that avoids the aforementioned disadvantages. Accordingly, cracks near the edges in the product are to be minimized or avoided. Furthermore, a longer service life of the mold and, in particular, its copper plates, especially the narrow sides of the mold, is to be achieved. Reduced wear should also reduce contamination of the slab surface with copper particles.

[0009] The solution to this problem by the invention is characterized in that the offset is formed by sections which are raised and recessed relative to the central region in the direction normal to the mold wall, wherein the offset is raised above the level of the central region in the upper region of the continuous casting mold, in particular in the upper quarter of the height of the continuous casting mold, and is recessed relative to the level of the central region in the lower region of the continuous casting mold, in particular in the lower quarter of the height of the continuous casting mold.

[0010] The central area is preferably flat.

[0011] The offset preferably connects continuously to the central area.

[0012] According to a preferred embodiment of the invention, the offset runs linearly over the width coordinate of the mold wall and connects to the central region with a transition radius.

[0013] It is also possible that the offset obeys a function (y = A(x, z)) in the form of a polynomial (e.g. third, fourth or fifth order) that defines the size of the offset in the direction normal to the mold wall over the width coordinate of the mold wall and the height coordinate of the continuous casting mold.

[0014] The change in offset over the height of the continuous casting mold is preferably greater in the lower half of the continuous casting mold than in the upper half thereof.

[0015] The continuous casting mold usually has two wide sides and two narrow sides, with the narrow sides having the aforementioned offset. The long sides may be free of the aforementioned profiling.

[0016] The invention is suitable for all types of molds, in particular for slab molds and bloom molds.

[0017] The invention therefore aims to provide the copper plate on the narrow side of the mold with a variable profile in the side area, which is preferably selected as a function of the nth degree (n, e.g., 3, 4, 5, or 6). Its intensity diminishes from top to bottom across the mold length or height.

[0018] The aforementioned offset continuously decreases or at least remains constant as it progresses from top to bottom, i.e. the protrusion of the mold wall in the side area towards the slab continuously decreases from top to bottom. This reduction in offset is particularly advantageous as it is concentrated in the lower half of the mold, where increased wear is to be expected due to the increasing strand shell thickness and the greater ferrostatic pressure. Accordingly, the proposed design results in less wear on the narrow-side copper plate in the mold exit area. This is associated with a lower risk of copper base material being erosion into the product, i.e. so-called star cracks on the product can be avoided or reduced.

[0019] The side areas therefore exhibit at least an offset from the planar surface of the narrow-side copper plate in the central area. The central surface preferably remains flat and at a constant inclination over at least two-thirds of the mold length.

[0020] The variation of the side areas over the height can be carried out in such a way that an increasingly negative offset of the side profile (ie a reduction of the surface away from the slab) is provided towards the mold outlet.

[0021] The proposed design of the copper plate wall of the narrow sides advantageously allows for optimal slab formation along the narrow sides in the upper area of ​​the mold, while the proposed shaping in the lower area of ​​the mold ensures that the slab rests on the mold with low friction and low wear on the tool. The specially proposed contouring of the edges of the cast slabs advantageously reduces the slab's tendency to crack. The edge areas of slabs made of crack-sensitive steel grades can thus be improved with a reduced number or severity of cracks through the use of the proposed optimized narrow-side plates.

[0022] The drawings illustrate exemplary embodiments of the invention. They show: Fig. 1 schematically shows a continuous casting mould in side view, Fig. 2 the continuous casting mold Fig. 1 in plan view, Fig. 3a shows the front view of a copper plate forming the narrow side of the continuous casting mold according to a first embodiment of the invention, Fig. 3b the Fig. 3a corresponding side view of the copper plate, Fig. 3c the to Fig. 3a corresponding top view of the copper plate, Fig. 3d the detail “A” according to Fig. 3c, Fig. 4a shows the front view of a copper plate forming the narrow side of the continuous casting mold according to a second embodiment of the invention, Fig. 4b the Fig. 4a corresponding side view of the copper plate, Fig. 4c the to Fig. 4a corresponding top view of the copper plate, Fig. 4d the detail “A” according to Fig. 4c, Fig. 5a shows the front view of a copper plate forming the narrow side of the continuous casting mold according to a third embodiment of the invention, Fig. 5b the Fig. 5a corresponding side view of the copper plate, Fig. 5c the to Fig. 5a corresponding top view of the copper plate and Fig. 5d the detail “A” according to Fig. 5c.

[0023] In Fig. 1 and Fig. Figure 2 shows a sketch of a continuous casting mold 1 consisting of four mold walls 2, 3. The mold 1 has two wide sides 9 and two narrow sides 10. This results in an inner side 4 of the four mold walls 2, 3, which defines the shape of the slab to be cast. The height of the mold 1 or the mold walls 2, 3 is indicated by L. The height coordinate is z.

[0024] Details of one of the mold walls are from the Fig. 3a to 3d, where a copper plate of one of the narrow sides 10 of the mold 1 is shown in the front view, in the side view and in the top view (or enlarged in Fig. 3d). The inner side 4 facing the interior of the mold is provided with a profile 5. The profile is characterized by a flat central area 6. Side areas 7 adjoin the central area 6, symmetrically to the central area 6.

[0025] The profile 5 is evident from the different sections 1 in the circle to 5 in the circle, which are shown in Fig. 3a and to the correspondingly marked courses in Fig. 3d correspond. Accordingly, it can be seen that the profiling 5 is determined by an offset 8 which changes over the height of the mold, i.e. over the coordinate z. While in the upper area of ​​the mold (see section 1 in the circle) the offset 8 protrudes or projects beyond the surface of the flat central area 6, i.e. has a positive value for the coordinate y normal to the surface 4 of the copper plate, the offset 8 decreases more and more as the height of the mold decreases (i.e. as the coordinate z increases). Right at the bottom - see section 5 in the circle - the surface of the inner side 4 is even recessed compared to the central area 7. At the level of section 4 in the circle, however, the inner side 4 has an overall flat profile across the entire width S of the mold wall.

[0026] Regarding the shape of the offset 8, it should be noted that it is essentially linear, with the transition between the central region 6 and the side region 7 being characterized by a transition radius R. In general, the curve y = A (x, z) can be represented as a higher-order polynomial, resulting (largely) in the curve shown in the figures. The y coordinate is the direction normal to the mold wall, while the x coordinate indicates the direction of the width coordinate of the mold wall.

[0027] In any case, it is essential that the inner side 4 provided with the profiling 5 has the central region 6 which extends over the entire height L and over at least half the width S of the inner side 4. The surface of the inner side 4 in the side regions 7 of the inner side 4 adjoining the central region 6 in the normal direction, i.e. in the y-direction, to the mold wall is in any case offset in sections compared to the surface of the inner side 4 in the central region 6; however, the offset changes over the height, i.e. in the z-direction, of the continuous casting mold.

[0028] Can be seen in Fig. 3a: The width of the edge region 7, indicated by K, can vary across the height of the mold. Accordingly, the central region 6 does not have to have a constant width.

[0029] In the Fig. 4a to 4d and in the Fig. 5a to 5d show alternative designs of the mold wall. Again, for different sections (1 in the circle to 5 in the circle), the course of the offset 8 (in Fig. 4d and 5d, respectively. This shows that there are different variants of the proposed idea. List of reference symbols: 1 continuous casting mold 2 mold wall 3 mold wall 4 Inside 5 Profiling 6 Central area 7 page area 8 Offset 9 wide side of the mold 10 narrow side of the mold L Height of the mold wall S Width of the mold wall x coordinate / direction of the width coordinate of the mold wall y R coordinate / direction normal to the mold wall z coordinate / direction at the height of the mold wall transition radius

Claims

[1] Continuous casting mold (1), comprising a number of mold walls (2, 3) which form a casting surface with their inner sides (4), wherein at least one of the inner sides (4) is provided with a profiling (5) so that the inner side (4) has a non-planar shape, wherein the inner side (4) provided with the profiling (5) has a central region (6) which extends over the height (L) and over at least half the width (S) of the inner side (4), wherein the surface of the inner side (4) in the side regions (7) of the inner side (4) adjoining the central region (6) is offset in the direction normal (y) to the mold wall (2, 3) at least in sections with respect to the surface of the inner side (4) in the central region (6), wherein the offset (8) varies over the height (z) of the continuous casting mold (1) and wherein the offset (8) is greater in the upper region of the continuous casting mold (1) than in the lower region of the continuous casting mold (1), characterized byin that the offset (8) is formed by sections which are raised and set back in relation to the central region (6) in the direction normal (y) to the mould wall (2, 3), the offset (8) being raised above the level of the central region (6) in the upper region of the continuous casting mould (1), in particular in the upper quarter of the height of the continuous casting mould (1), and being set back from the level of the central region (6) in the lower region of the continuous casting mould (1), in particular in the lower quarter of the height of the continuous casting mould (1). [2] Continuous casting mould according to claim 1, characterized by that the central area (6) is flat. [3] Continuous casting mould according to claim 1 or 2, characterized by that the offset (8) continuously connects to the central area (6). [4] Continuous casting mould according to claim 3, characterized bythat the offset (8) runs linearly over the width coordinate (x) of the mold wall (2, 3) and connects to the central area (6) with a transition radius (R). [5] Continuous casting mould according to claim 3, characterized by that the offset (8) obeys a function (y = A(x, z)) in the form of a polynomial which defines the size (y) of the offset (8) in the direction normal (y) to the mold wall (2, 3) over the width coordinate (x) of the mold wall (2, 3) and the height coordinate (z) of the continuous casting mold (1). [6] Continuous casting mould according to one of claims 1 to 5, characterized by that the change in the offset (8) over the height (z) of the continuous casting mold (1) is greater in the lower half of the height of the continuous casting mold (1) than in the upper half of the height of the continuous casting mold (1). [7] Continuous casting mould according to one of claims 1 to 6, characterized bythat it has two wide sides (9) and two narrow sides (10), wherein the narrow sides (10) are provided with the offset (8).

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