Method for continuous casting and rolling at increased casting speed followed by hot rolling of relatively thin metal strands, especially steel strands, and a continuous casting and rolling installation

Abstract

A method for continuous casting and rolling at increased casting speed followed by hot rolling of relatively thin metal strand, especially steel strand ( 1 ), where presetting of target temperatures ( 6 ) of the hot strip ( 2 ) reduces temperature losses in the hot strip ( 2 ) by increasing the temperatures of the work rolls ( 4 ) at a predetermined rate of increase, starting from a low initial temperature ( 5 ), and by adjusting the strip temperature ( 15 ) to a target rolling temperature ( 6 ) of the hot strip ( 2 ) and/or by automatically controlling or regulating the intensity of the roll cooling ( 18 ).

1 .- 17 . (canceled) 
     
     
         18 . A continuous casting and rolling installation with a continuous casting installation and a hot-strip finishing train ( 3 ), a heating device ( 8 ), and a cooling device for the work rolls ( 4 ) assigned to each rolling stand ( 3   a  . . .  3   n ), wherein the length of the work rolls ( 4 ) is adjusted to a temperature increase and that the work roll bearings are cooled and are connected to a circulating oil lubrication system or are lubricated by special grease. 
     
     
         19 . A continuous casting and rolling installation in accordance with  claim 18 , wherein the work rolls ( 4 ) are ground in a hot state. 
     
     
         20 . A continuous casting and rolling installation in accordance with  claim 18 , wherein the work rolls ( 4 ) are made of heat-resistant and wear-resistant materials. 
     
     
         21 . A continuous casting and rolling installation in accordance with  claim 20 , wherein HIP (hot isostatic pressing) rolls are provided for the rolling stands ( 3   a  . . .  3   n ) of the hot-strip finishing train ( 3 ). 
     
     
         22 . A continuous casting and rolling installation in accordance with  claim 18 , wherein an online computer model ( 7 ) incorporates a work roll temperature model ( 9 ) based on the measured work roll surface temperatures ( 10 ), the initial temperature ( 5 ) of the work roll ( 4 ), and the physical properties of the work roll ( 4 ). 
     
     
         23 . A continuous casting and rolling installation in accordance with  claim 22 , wherein the work roll temperature model ( 9 ) takes into account the maximum mean roll surface temperature ( 19 ), the maximum allowable temperature difference ( 23 ) between the work roll core ( 4   a ) and the work roll surface ( 4   b ), and the maximum allowable stress ( 24 ) in the work roll ( 4 ). 
     
     
         24 . A continuous casting and rolling installation in accordance with  claim 18 , wherein roller table covers are installed between the rolling stands ( 3   a  . . .  3   n ). 
     
     
         25 . A continuous casting and rolling installation in accordance with  claim 24 , wherein inert gas supply lines are provided between the front rolling stands ( 3   a  . . .  3   n ) under the roller table covers. 
     
     
         26 . A continuous casting and rolling installation in accordance with  claim 18 , wherein the pass program parameters ( 11 ) include at least the rolling force ( 12 ), the run-in and runout thickness ( 13 ), the rolling speed ( 14 ), the strip temperature ( 15 ), the thickness of the layer of scale ( 16 ), and the strip material ( 17 ). 
     
     
         27 . A continuous casting and rolling installation in accordance with  claim 25 , wherein the thickness decrease in the pass program is shifted to the rear region of the hot-strip finishing train ( 3 ). 
     
     
         28 . A continuous casting and rolling installation in accordance with  claim 18 , wherein a minimum runout thickness ( 13 ) is limited to a fixed value. 
     
     
         29 . A continuous casting and rolling installation in accordance with  claim 18 , wherein a hot-strip finishing train ( 3 ) is provided with about seven rolling stands (F 1  to F 7 ) for a cast strand thickness of H=50-90 mm and a minimum runout thickness ( 13 ) of 0.6 to 1.2 mm.