Device for casting strands of metal

Abstract

The invention is directed to a device for casting strands of metal, in particular steel, with a material supply vessel, the liquid metal being delivered to the carrying side of a circulating conveyor belt by means of the pouring nozzle of the material supply vessel. The conveyor belt comprises a thin, heat-resistant belt which circulates between a first deflection roller and a second deflection roller and which is shaped after the first deflection roller and in the region of the outlet nozzle to form a trough for receiving the liquid metal and resumes the shape of a flat belt in proximity to the second deflection roller. In order to reduce stresses on the belt, it is proposed that at least one of the deflection rollers is cambered in a convex manner.

1 - 21 . (canceled) 
     
     
         22 . A device for casting strands of metal, the device comprising:
 an outlet nozzle configured to supply liquid metal from a material supply vessel;   a circulating conveyor belt assembly being configured to receive the liquid metal from the outlet nozzle on a carrying side, the conveyor belt assembly comprising:
 a first deflection roller; 
 a second deflection roller; and 
 a thin, heat-resistant belt that circulates between the first deflection roller and the second deflection roller, the belt being shaped to form a trough for receiving the liquid metal between the first deflection roller and the second deflection roller in a region of the outlet nozzle, the circulating conveyor belt resuming the shape of a flat belt proximate to the second deflection roller, 
   wherein at least one of the first deflection roller and the second deflection roller is convexly cambered.   
     
     
         23 . The device according to  claim 22 , wherein the camber is selected such that a shortening of the belt resulting from the formation of the trough profile is at least partially compensated. 
     
     
         24 . The device according to  claim 22 , wherein the camber is calculated according to the following formulae:
     B   B /2 =X   B   +X+X   T   (1)
     Δ L   XB   =L−L   V =√{square root over ( L   2   +X   2   +Y   2 )},  (2)
   
       wherein
 B B  is a width of the belt 
 B T  is a width of the trough, 
 L is a length of a final trough profile between an entry and exit, 
 L V  is a length of a space diagonal in longitudinal direction of the trough, 
 X is an X coordinate for calculating L V , 
 X B  is a distance from point C, 
 X T  is a distance from a center of the belt or trough, 
 Y is a Y coordinate for calculating L V . 
 
     
     
         25 . The device according to  claim 24 , wherein a change in belt length due to varying temperature distribution over a width of the belt is taken into account in the camber and is calculated according to the following formula:
   Δ l   Temp   =L   Trough α( T   M   −T   R ),  (3)
   
       wherein
 L Trough  is a length of the trough, 
 T M  is a temperature in a center of the belt 
 T R  is a temperature at an edge area of the belt, and 
 α is a coefficient of expansion of a belt material. 
 
     
     
         26 . The device according to  claim 25 , wherein the camber of the deflection rollers for a homogenized tensile stress over the width of the belt is calculated for a given trough profile and temperature profile by superposition. 
     
     
         27 . The device according to  claim 26 , wherein a first deflection roller camber is smaller than a second deflection roller camber. 
     
     
         28 . The device according to  claim 22 , wherein the camber is changable by a pressure medium in at least one of the deflection rollers. 
     
     
         29 . The device according to  claim 28 , wherein a profiled cavity is provided at a roller shell for applying pressure. 
     
     
         30 . The device according to  claim 22 , wherein each of a belt entry length and a belt exit length is at least 500 mm. 
     
     
         31 . The device according to  claim 30 , wherein at least one of a maximum belt entry length and a maximum belt exit length is selected such that the camber due to the trough profile is not greater than 2%. 
     
     
         32 . The device according to  claim 22 , wherein the belt is shaped by the deflection roller continuously over a distance to form at least one of the trough profile and flat belt. 
     
     
         33 . The device according to  claim 22 , wherein the belt material comprises a thermal shock-resistant alloy comprising at least one of CuNi and Fe. 
     
     
         34 . The device according to  claim 22 , wherein the belt material comprises a single-phase or multiple-phase Cu alloy. 
     
     
         35 . The device according to  claim 22 , wherein the belt material comprises a nickel-based alloy. 
     
     
         36 . The device according to  claim 22 , wherein the belt has a thickness greater than about 0.5 mm and less than about 2.0 mm. 
     
     
         37 . The device according to  claim 32 , wherein the trough profile is arc-shaped. 
     
     
         38 . The device according to  claim 32 , wherein the trough profile is symmetrical. 
     
     
         39 . The device according to  claim 32 , wherein the trough profile has substantially straight-line regions at both ends. 
     
     
         40 . The device according to  claim 32 , wherein sides of the trough profile are higher than the casting profile by about 10 mm. 
     
     
         41 . The device according to  claim 40 , wherein the sides have an angular deviation of +/−25 degrees relative to a perpendicular of the belt when flat. 
     
     
         42 . The device according to  claim 32 , wherein the trough profile is adapted to shrinkage of a casting cross section by an adjustment of the rollers in casting direction over the length of the trough. 
     
     
         43 . The device according to  claim 22 , wherein a change in belt length due to varying temperature distribution over a width of the belt is taken into account in the camber and is calculated according to the following formula:
   Δ l   Temp   =L   Trough α( T   M   −T   R ),  (3)
   
       wherein
 L Trough  is a length of the trough, 
 T M  is a temperature in a center of the belt 
 T R  is a temperature at an edge area of the belt, and 
 α is a coefficient of expansion of a belt material.