Method and apparatus for high-speed continuous casting plants with a strand thickness reduction during solidification

Abstract

A method and an apparatus for continuous casting plants for producing strands whose cross-section is reduced during solidification. The continuous casting method for producing strands, wherein the cross-section of the strands is reduced during the solidification, includes casting into a mold, particularly an oscillating mold, and reducing the strand cross- section linearly over a minimum length of the strand guiding unit immediately underneath the mold, i.e., casting and rolling, and subsequently carrying out a further strand cross-section reduction through the remaining strand guiding unit, i.e., soft reduction, up to maximum reduction immediately in front of the final solidification or sump tip.

I claim:  
     
         1 . A method of continuous casting for producing strands, wherein a cross-section of the strands is reduced during solidification, the method comprising casting in a mold and reducing the strand cross-section linearly over a minimum length of a strand guiding means immediately below the mold for carrying out casting and rolling, carrying out a subsequent further strand cross-section reduction over a remaining length of the strand guiding means for effecting soft reduction up to a maximum of immediately in front of an end solidification or sum tip.  
     
     
         2 . The method according to  claim 1 , comprising oscillating the mold.  
     
     
         3 . The method according to  claim 1 , comprising, in the case of rectangular strand shapes, reducing the cross-section by a reduction in thickness direction.  
     
     
         4 . The method according to  claim 3 , comprising reducing the thickness of the strand by at most 60% of a strand thickness at a mold exit.  
     
     
         5 . The method according to  claim 1 , comprising reducing a thickness of thin slabs with a solidification thickness of 120-50 mm.  
     
     
         6 . The method according to  claim 1 , comprising reducing a strand thickness by dividing a total thickness reduction into the rolling and casting reduction immediately underneath the mold and the soft reduction in the remaining strand guiding means at a maximum casting speed with a rate of less than 1.25 mm/s.  
     
     
         7 . The method according to  claim 1 , comprising casting with a maximum casting speed of 12 m/min.  
     
     
         8 . The method according to  claim 1 , comprising reducing a strand thickness during soft reduction linearly over a solidification length.  
     
     
         9 . The method according to  claim 1 , comprising reducing a strand thickness during soft reduction non-linearly and in accordance with a square root function over a solidification period.  
     
     
         10 . The method according to  claim 1 , wherein a total thickness reduction is carried out linearly and steadily from a mold exit to at most directly following the sum tip.  
     
     
         11 . The method according to  claim 1 , comprising carrying out bending of the strand from the vertical into an inner circular arc of a vertical bending continuous casting plant in the range of soft reduction.  
     
     
         12 . The method according to  claim 1 , comprising carrying out casting and rolling exclusively in a vertical strand guiding means without the lowest liquidus point leaving the strand guiding means at a maximum casting speed.  
     
     
         13 . A continuous casting plant for producing strands, wherein a cross-section of the strands is reduced during solidification, the continuous casting plant comprising: 
 an oscillating mold;    a segment 0 in which the strand is linearly reduced in its cross-section over a length of at least 1 m by at most 40%;    a remaining strand guiding means for reducing the strand in its cross-section up to at most immediately following a sump tip for carrying out soft reduction; wherein    a total reduction of the strand cross-section in the segment  0  and the remaining strand guiding means is up to 60%.    
     
     
         14 . The continuous casting plant according to  claim 13 , wherein, for casting rectangular shapes, the segment  0  and subsequent segments are configured for a cross-section reduction by reducing the strand thickness.  
     
     
         15 . The continuous casting plant according to  claim 13 , wherein, for reducing the strand thickness, the segment  0  comprises at an exit thereof two clamping cylinders controlled with respect to position and force.  
     
     
         16 . The continuous casting plant according to  claim 13 , wherein the segment  0  is configured for reducing the strand thickness by at most 100 mm.  
     
     
         17 . The continuous casting plant according to  claim 13 , wherein segments of the remaining strand guiding means comprise position-controlled and force-controlled strand thickness adjustments.  
     
     
         18 . The continuous casting plant according to  claim 17 , wherein each segment has an odd number of pairs of rollers, wherein the number of pairs of rollers is at least  3 .  
     
     
         19 . The continuous casting plant according to  claim 18 , wherein each third pair of rollers is a pair of driven rollers.  
     
     
         20 . The continuous casting plant according to  claim 18 , wherein each pair of rollers includes an upper roller, wherein the upper rollers of non-driven pairs of rollers are provided with position-controlled and force-controlled clamping cylinders.  
     
     
         21 . The continuous casting plant according to  claim 18 , wherein the pairs of rollers include upper rollers, each upper roller of a pair of non-driven rollers and a cylinder therefor comprising a means for permitting swinging of the rollers by +/−5 degrees in casting direction.  
     
     
         22 . The continuous, casting plant according to  claim 13 , wherein the segment  0  is arranged vertically and has a maximum length of 5 m.  
     
     
         23 . The continuous casting plant according to  claim 22 , wherein a first segment following the segment  0  has at least one bending point for bending the strand from the vertical into a circular arc.  
     
     
         24 . The continuous casting plant according to  claim 23 , wherein at least one segment following the first segment comprises at least one return bending point for straightening the strand from the circular into the horizontal.  
     
     
         25 . The continuous casting plant according to  claim 24 , wherein the horizontal portion of the strand guiding means has a length of at least 4 m.  
     
     
         26 . The continuous casting plant according to  claim 13 , wherein the mold has concave mold walls.  
     
     
         27 . The continuous casting plant according to  claim 13 , further comprising a submerged pouring pipe for casting and casting powder.  
     
     
         28 . The continuous casting plant according to  claim 13 , wherein wide sides of the mold are shaped concavely in horizontal direction, and wherein the concavity of the wide sides decreases toward a mold exit.  
     
     
         29 . The continuous casting plant according to  claim 13 , wherein narrow sides of the mold are shaped concavely in horizontal direction.