Cold rolling mill and a rolling method

Abstract

The present invention controls the ever-changing thermal crowns to give good strip shapes during rolling without causing any flaws in the rolled surfaces and with quick responses to ever-changing thermal crowns. A 6 -high rolling mill in accordance with the present invention wherein each of the working rolls 2 which are equipped with a shifting means has a locally gradually-thickened-toward-end part (or a local concave crown 2 a ) on one end of the roll, the working rolls 2 are disposed so that the locally gradually-thickened-toward-end parts of the working rolls 2 may be vertically symmetrically with a point, a decremental bender 10 b which works to narrow the gap between the working rolls is provided as a first shape control means, both the local concave crowns 2 a and the roll bender 10 b are used to control thermal crowns, and an incremental bender 11 a which controls bending of the intermediate rolls 3 is provided as a second shape control means which controls so that the center of a strip may have a concave crown.

What we claim is:  
     
         1 . A cold rolling mill of at least four-high or more-than-4-high comprising first shifting equipment which can shift a pair of upper and lower working rolls in opposite directions and roll bending equipment which controls the bending of said pair of working rolls, wherein said cold rolling mill further comprises 
 locally gradually-thickened-toward-end parts provided on said working rolls at one ends thereof so as to be symmetrical with respect to a point,    a first shape control means for controlling a thermal crown formed on each of said pair of working rolls together with said locally gradually-thickened-toward-end parts, and    a second shape control means for controlling to form a concave crown in the center of said rolled material.    
     
     
         2 . A cold rolling mill in accordance with  claim 1 , wherein said roll bending equipment comprises 
 decremental bending equipment and said first shape control means is said decremental bending equipment.    
     
     
         3 . A cold rolling mill in accordance with  claim 1 , wherein said rolling mill is a 6-high mill comprising a pair of upper and lower intermediate rolls and a second shifting equipment which can rotate said pair of upper and lower intermediate rolls in opposite directions, said first shape control means is said second shifting equipment.  
     
     
         4 . A cold rolling mill of at least four-high or more-than 4-high comprising first shifting equipment which can shift a pair of upper and lower working rolls in opposite directions and roll bending equipment which controls the bending of said pair of working rolls, wherein 
 each of said upper and lower working rolls has a locally gradually-thickened-toward-end part in which the diameter increases toward one end of the working roll,    said locally gradually-thickened-toward-end parts are disposed vertically symmetrically with respect to a point,    said roll bending equipment as the first shape control means comprises decremental bending equipment which works to narrow the gap between said pair of upper and lower working rolls, and    said rolling mill further comprises a second shape control means for controlling to form a concave crown in the center of said rolled material.    
     
     
         5 . A cold rolling mill of at least 4-high or more-high for a cold reversible rolling facility comprising first shifting equipment which can shift a pair of upper and lower working rolls in opposite directions and roll bending equipment which controls the bending of said pair of working rolls, wherein 
 each of said upper and lower working rolls has a locally gradually-thickened-toward-end part which increases its diameter on one end of the working roll,    said locally gradually-thickened-toward-end parts are disposed vertically symmetrically with respect to a point,    said roll bending equipment as the first shape control means comprises decremental bending equipment which works to narrow the gap between said pair of upper and lower working rolls, and    said rolling mill further comprises a second shape control means for controlling to form a concave crown in the center of said rolled material.    
     
     
         6 . A cold rolling mill of at least four-high or more-high for a cold aluminum rolling facility comprising first shifting equipment which can shift a pair of upper and lower working rolls in opposite directions and roll bending equipment which controls the bending of said pair of working rolls, wherein 
 each of said upper and lower working rolls has a locally gradually-thickened-toward-end part in which the diameter increases on one end of the working roll,    said locally gradually-thickened-toward-end parts are disposed vertically symmetrically with respect to a point,    said roll bending equipment as the first shape control means comprises decremental bending equipment which works to narrow the gap between said pair of upper and lower working rolls, and    said rolling mill further comprises a second shape control means for controlling to form a concave crown in the center of said rolled material.    
     
     
         7 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , wherein said rolling mill is a 6-high mill comprising a pair of upper and lower intermediate rolls which can move axially and said second shape control means is equipped with an incremental bending equipment which controls the bending of said pair of intermediate rolls.  
     
     
         8 . A cold rolling mill in accordance with  claim 7 , wherein each of said pair of upper and lower intermediate rolls have a locally tapered part on the side where the gradually-thickened-toward-end part exists so that the tapered part may be engaged with said gradually-thickened-toward-end part of each working roll and the rate of diameter changing of said tapered part is equal to or greater than the rate of diameter changing of the gradually-thickened-toward-end part.  
     
     
         9 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , wherein said rolling mill is a 6-high mill comprising a pair of upper and lower intermediate rolls each of which has a curved roll crown containing both a maximum and a minimum all over the roll and said second shape control means has shifting equipment which shifts said pair of upper and lower intermediate rolls in opposite directions.  
     
     
         10 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , wherein said rolling mill is a 6-high mill comprising a pair of upper and lower intermediate rolls which can move axially and said second shape control means has a roll-crossing mechanism which tilts at least said pair of intermediate rolls horizontally with the center of the mill approximately as the center of rotation.  
     
     
         11 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , wherein said rolling mill is a 4-high rolling mill and said second shape control means is equipped with a roll-crossing mechanism which tilts said pair of working rolls or one pair of rolls supporting said working rolls with the center of the mill approximately as the center of rotation.  
     
     
         12 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , 
 wherein 
 said rolling mill is a 4-high mill,  
 each of said pair of supporting rolls for supporting said working rolls has a roll crown which is tapered from about the center of the roll towards one end of the roll,  
 said roll crowns are disposed vertically symmetrically with respect to a point, and  
 said second shape control means is equipped with the shifting equipment which can move said supporting rolls in different directions.  
 
 
     
     
         13 . A cold rolling mill in accordance with any of claims  1  and  4  to  6 , wherein the diameter of each of said upper and lower working rolls is expressed by  
       1/6 Wm+ 50 ≦Dw≦ 1/6 Wm+ 250  wherein 
 Dw is the diameter of each of the working rolls and Wm is the maximum width of a sheet to be rolled.  
   
     
     
         14 . A cold rolling mill comprising: 
 a pair of working rolls each provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction;    intermediate rolls supporting said working rolls, respectively;    a roll bending device for applying roll bending force on said working rolls; and    an intermediate roll bending device for applying roll bending force on said intermediate rolls.    
     
     
         15 . A cold rolling mill comprising: 
 a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, and rolling rolling materials, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction;    intermediate rolls supporting said working rolls, respectively;    backup rolls supporting said intermediate rolls, respectively;    a roll bending device for applying roll bending force on said working rolls; and    an intermediate roll crossing mechanism for crossing the roll axes of said intermediate rolls in a horizontal plane against a perpendicular direction to the rolling material traveling direction, or a roll shifting device for shifting said intermediate rolls along the roll axis direction.    
     
     
         16 . A cold rolling mill comprising: 
 a pair of working rolls each provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction;    supporting rolls supporting said working rolls, respectively;    a roll bending device for applying roll bending force on said working rolls; and    a supporting roll shifting device for shifting said supporting rolls along the roll axis direction.    
     
     
         17 . A cold rolling mill comprising: 
 a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, and rolling rolling materials, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction;    supporting rolls supporting said working rolls, respectively;    a roll bending device for applying roll bending force on said working rolls; and    a roll crossing mechanism for crossing the roll axes of said working rolls in a horizontal plane against a perpendicular direction to the rolling material traveling direction.    
     
     
         18 . A rolling method which comprises the steps of: 
 using shape detectors which measure the shapes of a sheet at least after being rolled and a 4-high or more-high cold rolling mill which comprises 
 shifting equipment which can shift one pair of upper and lower working rolls each of which has a locally gradually-thickened-toward-end part on one end of respective working rolls with the locally gradually-thickened-toward-end parts disposed vertically symmetrically with respect to a point,  
 roll bending equipment which controls bending of said pair of working rolls and has, as a first shape control means, decremental bending equipment which works to narrow the gap between said pair of working rolls, and  
 a second shape control means for forming a concave crown in the center of said rolled material,  
   adjusting the position of said one pair of upper and lower working rolls by said shifting equipment so that side edges of the rolled sheet may be limited by said gradually-thickened-toward-end parts of said working rolls before starting rolling,    approximately fixing the shift position of said pair of upper and lower working rolls while rolling is in progress, and    determining the operations of said first and second shape control means so that their effects on the sheet may work reversely according to the output of said shape detectors.    
     
     
         19 . A rolling method in accordance with  claim 18 , wherein the operation of said first shape control means is determined according to the output of said shape detector placed near the edge of the sheet and the operation of said second shape control means is determined according to the output of said shape detector placed near the center of the sheet.  
     
     
         20 . A rolling method which comprises the steps of: 
 using shape detectors which measure the shapes of a sheet at least after being rolled and a 6-high cold rolling mill which comprises 
 first shifting equipment which can shift one pair of upper and lower working rolls each of which has a locally gradually-thickened-toward-end part on one end of respective working rolls with the locally gradually-thickened-toward-end parts disposed vertically symmetrically with respect to a point,  
 second shifting equipment which can rotate one pair of upper and lower intermediate rolls which support said working rolls reversely, and  
 a second shape control means for forming a concave crown in the center of said rolled material,  
   adjusting the position of said one pair of upper and lower working rolls by said first shifting equipment so that side edges of the rolled sheet may be limited by said gradually-thickened-toward-end parts of said working rolls before starting rolling,    approximately fixing the shift position of said pair of upper and lower working rolls while rolling is in progress, and    determining the operations of said second shifting equipment and said shape control means according to the output of said shape detectors.    
     
     
         21 . A rolling method in accordance with  claim 20 , wherein the operation of said second shifting equipment is determined according to the output of said shape detector placed near the edge of the sheet and the operation of said shape control means is determined according to the output of said shape detector placed near the center of the sheet.  
     
     
         22 . A rolling method of a cold rolling mill comprising a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction, intermediate rolls supporting said working rolls, respectively, and backup rolls supporting said intermediate rolls, respectively, wherein said method comprises the steps of 
 controlling thermal crown during rolling by applying roll bending force on said working rolls, and controlling body crow at a central portion of the plate depth by applying roll bending force on said intermediate rolls.    
     
     
         23 . A rolling method of a cold rolling mill comprising a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction, intermediate rolls supporting said working rolls, respectively, and backup rolls supporting said intermediate rolls, respectively, wherein said method comprises the steps of 
 controlling thermal crown during rolling by applying roll bending force on said working rolls,    controlling body crown at a central portion of the plate width by crossing the roll axes of said intermediate rolls in a horizontal plane against a perpendicular direction to the rolling material traveling direction, or shifting said intermediate rolls along the roll axis direction.    
     
     
         24 . A rolling method of a cold rolling mill comprising a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction, and support rolls supporting said working rolls, respectively, wherein said method comprises the steps of 
 controlling thermal crown during rolling by applying roll bending force on said working rolls, and    controlling body crow at a central portion of the plate depth by shifting said support rolls along a roll axis direction.    
     
     
         25 . A rolling method of a cold rolling mill comprising a pair of working rolls each, provided with a roll-contour shape having a portion thickened-toward-end which increases in diameter toward a roll end in the vicinity of the roll end on one end side of a roll barrel portion thereof, and rolling rolling materials, said working rolls being arranged so that said thickened-toward-end portions are positioned at places on the opposite sides of the barrel portions in the roll axis direction, and support rolls supporting said working rolls, respectively, wherein said method comprises the steps of 
 controlling thermal crown during rolling by applying roll bending force on said working rolls, and    controlling body crow at a central portion of the plate depth by crossing the roll axes of said work rolls in a horizontal plane against a perpendicular direction to the rolling material traveling direction.