Title of Invention

"MOULD TUBE"

Abstract

A mould tube made of copper for the continuous casting of metals, which has a rectangular inner and outer cross-section with rounded longitudinal corner regions (2) as well as a nominal wall thickness (WD), which is 8% to 10% of the distance (A) between the inner surfaces (5) located facing each other at the mouth (4) of the tube, the inner surfaces (5) being indirectly under the heat-removing influence of a coolant which can be supplied from outer face of the tube wall (2, 3), the wall thickness (WD1) in the longitudinal corner regions (2) being smaller in dimension by 10% to 40% compared to the wall thickness (WD) of the wall regions (3) between the longitudinal corner regions (2), characterised in that the wall thickness reduction in the longitudinal corner regions (2) is limited to the height range (11), in which the level of the liquid metal is located.

Full Text

The invention relates a mould tube made of copper for continuous casting of metals Prior art enumerates mould tubes with rectangular inner and outer cross-sections as well as with rounded longitudinal corner regions, which have a nominal wall thickness, which amounts to 8 % to 10 % of the distance between the inner surfaces facing each other at the mouth of the tube. Further, it is known to subject the inner surfaces of mould tubes indirectly to the heat removing effect of the coolant supplied to the outer face of the tube wall. For this, the mould tubes can be provided with jackets suited to the external contours, which form precisely defined gap, together with the external surfaces, through which the coolant is passed. Further, the coolant can flow through coolant channels provided vertically in the walls of the mould tubes. Finally, spraying outer surfaces of the mould tubes with coolant through spray nozzles is also known (in prior art). The heat that is produced while attempting to increase the casting speeds, namely beyond 2.5 m/min, can only be transmitted partially to the heat carrying coolant due to the limited heat conducting capacity of the basic material of the mould tubes. The consequences are partial overheating and subsequent damage to the inner surfaces of the mould tubes. This fact can be observed especially in the height ranges of the varying liquid metal level or in the region of the first phase of primary solidifications of the metal to be cast, since maximum heat is produced there. The object of the invention is to create a mould tube out of copper for continuous casting, which ensures a perfect transfer of heat from the casting metal to the coolant, at casting speeds > 2.5 m/min. The present invention aims to solve this problem in two alternative ways as described below : 2 According to the first alternative, the wall thickness of the rectangular mould tube in the longitudinal corner regions measures 10 % to 40% less than the wall thickness in the wall regions between the longitudinal corner regions. By this measure, the heat that is produced, can be transferred perfectly, even at casting speeds > 2.5 m/min, to the coolant in particular and definitely independent of whether the coolant is led in the gap between the mould tube and the jacket surrounding the mould tube, or whether the coolant flows in coolant channels in the wall of the mould tube, or whether the coolant is sprayed directly on the outer surfaces of the mould tube. Preferably, the wall thickness in the longitudinal corner regions measures less than the wall thickness in the wall regions between the longitudinal corner regions by 25 % to 30 %. The reduction in wall thickness can extend over the entire length of the mould tube. But it is also conceivable, depending on the particular spatial relationships, that, the wall thickness reduction in the longitudinal corner areas is limited to a height range, in which the particular liquid metal level of the liquid metal lies. According to a second alternative, the wall thickness of the mould tube is reduced to 10 % to 40 % of the nominal wall thickness in the height range of the liquid metal level of the liquid metal along the entire perimeter. The cross-section of the mould tube can be multi-cornered, that is, e.g., rectangular, or also round. Here also, the preferred wall thickness reduction amounts to 25 % to 30 % of the nominal wall thickness. The liquid metal level in the mould tube lies in a height range, which extends from the filler face up to about 500 mm below the filler face. Based on experience, the height level of the liquid metal level lies, preferably between 80 mm and 180 mm below the filler face. 3 Accordingly, the present invention provides for a mould tube made of copper for the continuous casting of metals, which has a rectangular inner and outer cross-section with rounded longitudinal corner regions as well as a nominal wall thickness, which is 8% to 10% of the distance between the inner surfaces located facing each other at the mouth of the tube, the inner surfaces being indirectly under the heat-removing influence of a coolant which can be supplied from outer face of the tube wall, the wall thickness in the longitudinal corner regions being smaller in dimension by 10% to 40% compared to the wall thickness of the wall regions between the longitudinal corner regions, characterised in that the wall thickness reduction in the longitudinal corner regions is limited to the height range, in which the level of the liquid metal is located. 3A BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The invention is described in detail below based on the embodiments illustrated in the drawings. They show: Figure 1 a mould tube in perspective; Figure 2 magnified top view of the mould tube of figure 1 with three different cooling variants ; Figure 3 another type of design of a mould tube in perspective; Figure 4 a third type of design of a mould tube in perspective and Figure 5 magnified top view of the mould tube of figure 4. A mould tube out of copper for continuous casting of metals, especially steel, is designated with 1 in figures 1 and 2. The mould tube 1 has a rectangular inner and outer cross-section with inner and outer rounded longitudinal corner regions 2. The so-called nominal wall thickness WD of the wall regions 3 between the longitudinal corner regions 2 amounts to 8 % to 10 % of the distance A of the inner surfaces 5 facing each other at the mouth of the tube 4. The wall thickness WD1 in the longitudinal corner regions 2 measures 10 % to 40 % less than the wall thickness WD in the wall regions 3 between the longitudinal corner regions 2. The different wall thickness WD and WD1 of the mould tube 1 of the figures 1 and 2 extend over the entire height H (length) of the mould tube 1. 4 The cooling of the mould tube 1 can, according to the first type of design depicted in figure 2, takes place through a coolant that flows through the space 6, between the outer surface 7 of the mould tube 1 and the jacket 8, which covers the mould tube 1 with a definite distance A1. A second type of design illustrated in figure 2 provides for longitudinal channels 9 made in the wall regions 3 of the mould tube 1, which are supplied with a suitable coolant. Finally, figure 2 shows still another type of design of a mould tube, in which the outer surfaces 7 of the mould tube 1 are cooled in parts or all over by means of a coolant that is sprayed on these surfaces 7 from nozzles 10. Figure 3 shows a mould tube 1a out of copper for continuous casting of metals, in which the reduction in wall thickness in the longitudinal corner regions 2 is limited to a height range 11, in which the level of the liquid metal, not illustrated in detail, lies. This height range 11 extends, as a rule, between the filler face 12 of the mould tube 1a and a region, which lies about 500 mm below the filler face 12. Mould tube 1a can be cooled in the same manner as the cooling of the mould tube 1. In this respect, it is not necessary to repeat the explanation. It is evident from the observation common to figures 2 and 3, how the wall thickness reduction in the longitudinal corner regions 2 occurs. The original shape of the outer perimeter of the mould tube 1a in the lower height range is illustrated in figure 2 by broken line 13. In the case of the embodiment of mould tube 1b out of copper for continuous casting of metals according to figures 4 and 5, the wall thickness WD2 of the tube wall 16 is reduced to 10 % to 40% of the nominal wall thickness WD3 in the height range 14 of the level of the liquid metal, not illustrated in detail, along the entire perimeter. This height range 14 extends to about 500 mm from the filler face 12a in the direction of the tube mouth 4a. The liquid metal level lies as such mostly in a height range 15 of between 80 mm and 180 mm below the filler face 12a. 5 For this type of execution also, the nominal wall thickness WD3 amounts to 8% to 10 % of the distance A2 of the inner surfaces 5a facing each other at the tube mouth 4a. The embodiment, as per figures 4 and 5 of a mould tube 1b, can be cooled in the same way as was explained on the basis of figure 2. In this respect, a repeat description can be omitted. 6 Reference numerals used in the drawings 1 - Mould tube 1a - Mould tube 1b- Mould tube 2 - Longitudinal corner region of 1 3 - Wall region between 2 4 - Tube mouth of 1 4a-TUBE mouth of 1b 5 - inner surfaces of 1 5a - inner surfaces of 1 b 6 - Gap between 7 and 8 7 - outer surfaces of 1 8 - Jacket around 1 9 - Longitudinal channels in 3 10 - Nozzles 11 - Height range of 1 a 12-Filler face of 1a 12a-Filler face of 1b 13 - circumferential path 14 - Height range of 1b 15 - Height range of 1b 16-Tube wall of 1b A - Distance of 5 A1 - Distance of 7 and 8 A2 - Distance of 5a H - Height of 1 WD - nominal wall thickness of 3 WD1 - Wall thickness of 2 WD2- Wall thickness of 14 WD3 - nominal wall thickness of 1b 7 WE CLAIM : 1. Mould tube made of copper for the continuous casting of metals, which has a rectangular inner and outer cross-section with rounded longitudinal corner regions (2) as well as a nominal wall thickness (WD), which is 8% to 10% of the distance (A) between the inner surfaces (5) located facing each other at the mouth (4) of the tube, the inner surfaces (5) being indirectly under the heat-removing influence of a coolant which can be supplied from outer face of the tube wall (2, 3), the wall thickness (WD1) in the longitudinal corner regions (2) being smaller in dimension by 10% to 40% compared to the wall thickness (WD) of the wall regions (3) between the longitudinal corner regions (2), characterised in that the wall thickness reduction in the longitudinal corner regions (2) is limited to the height range (11), in which the level of the liquid metal is located. 2. Mould tube as claimed in claim 1, wherein the wall thickness (WD1) in the longitudinal corner regions (2) is smaller in dimension by 25% to 30% compared to the wall thickness (WD) in the wall regions (3) between the longitudinal corner regions (2). 3. Mould tube as claimed in claim 1 or 2, wherein the level of the liquid metal in a height range (11,14) is up to 500 mm below the filler face (12, 12a). 4. Mould tube as claimed in any one of claims 1 to 3, wherein the level of the liquid metal in a height range (15) is between 80 mm and 180 mm below the filler face (12a). 8 5. Mould tube substantially as herein described, particularly with reference to the accompanying drawings. A mould tube made of copper for the continuous casting of metals, which has a rectangular inner and outer cross-section with rounded longitudinal corner regions (2) as well as a nominal wall thickness (WD), which is 8% to 10% of the distance (A) between the inner surfaces (5) located facing each other at the mouth (4) of the tube, the inner surfaces (5) being indirectly under the heat-removing influence of a coolant which can be supplied from outer face of the tube wall (2, 3), the wall thickness (WD1) in the longitudinal corner regions (2) being smaller in dimension by 10% to 40% compared to the wall thickness (WD) of the wall regions (3) between the longitudinal corner regions (2), characterised in that the wall thickness reduction in the longitudinal corner regions (2) is limited to the height range (11), in which the level of the liquid metal is located.

Documents:

00442-kol-2003-abstract.pdf

00442-kol-2003-claims.pdf

00442-kol-2003-correspondence.pdf

00442-kol-2003-description(complete).pdf

00442-kol-2003-drawings.pdf

00442-kol-2003-form-1.pdf

00442-kol-2003-form-18.pdf

00442-kol-2003-form-2.pdf

00442-kol-2003-form-3.pdf

00442-kol-2003-form-5.pdf

00442-kol-2003-g.p.a.pdf

00442-kol-2003-letters patent.pdf

00442-kol-2003-priority document others.pdf

00442-kol-2003-priority document.pdf