Device for the Continuous Lengthening of a Metal Strip by Traction, and Method for Operating One Such Device

Abstract

The invention relates to a device ( 1 ) for the continuous lengthening of a metal strip ( 2 ) by traction, said device comprising, in the strip transporting direction (R), at least three S-roll units ( 3, 4, 5, 6, 7 ) each provided with at least two rolls ( 8, 9 10, 11, 12, 13, 14, 15, 16, 17 ). According to the invention, the rolls ( 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 ) are positioned in such a way that the metal strip ( 2 ) is wound round them at a roll periphery angle (a) of more than 180°, and at least the second S-roll unit ( 4 ) in the strip transporting direction (R) comprises two rolls ( 10, 11 ) with different-sized diameters (D 10 , D 11 ).

1 . A device ( 1 ) for the continuous stretcher leveling of metal strip ( 2 ), which device ( 1 ) has at least three bridles ( 3 ,  4 ,  5 ,  6 ,  7 ) in the direction of strip transport (R), with each bridle ( 3 ,  4 ,  5 ,  6 ,  7 ) having at least two rolls ( 8 ,  9 ;  10 ,  11 ;  12 ,  13 ;  14 ,  15 ;  16 ,  17 ), where the rolls ( 8 ,  9 ,  10 ,  11 ,  12 ,  13 ,  14 ,  15 ,  16 ,  17 ) are positioned in such a way that the metal strip ( 2 ) wraps around them over a contact roll wrap angle (α) of more than 180°, wherein at least the second bridle ( 4 ) in the direction of strip transport (R) has two rolls ( 10 ,  11 ) with different diameters (D 10 , D 11 ).  
     
     
         2 . A device in accordance with  claim 1 , wherein the second roll ( 11 ) of the second bridle ( 4 ), which is downstream of the first roll ( 10 ) of the second bridle ( 4 ) in the direction of strip transport (R), is the roll with the larger diameter (D 11 ).  
     
     
         3 . A device in accordance with  claim 1  or  claim 2 , wherein it has five bridles ( 3 ,  4 ,  5 ,  6 ,  7 ) with at least two rolls each ( 8 ,  9 ;  10 ,  11 ;  12 ,  13 ;  14 ,  15 ;  16 ,  17 ).  
     
     
         4 . A device in accordance with  claim 3 , wherein the fourth bridle ( 6 ) in the direction of strip transport (R) has two rolls ( 14 ,  15 ) with different diameters (D 14 , D 15 ).  
     
     
         5 . A device in accordance with  claim 4 , wherein the downstream roll ( 15 ) of the fourth bridle ( 6 ) in the direction of strip transport (R) has the smaller diameter (D 15 ).  
     
     
         6 . A device in accordance with any of  claims 1  to  5 , wherein the diameter of the large-diameter roll ( 11 ,  14 ) of the bridle ( 4 ,  6 ) is at least 1.25 times larger than the diameter of the small-diameter roll ( 10 ,  15 ).  
     
     
         7 . A device in accordance with  claim 6 , wherein the diameter of the large-diameter roll ( 11 ,  14 ) of the bridle ( 4 ,  6 ) is at least 1.5 times larger than the diameter of the small-diameter roll ( 10 ,  15 ) and preferably twice as large.  
     
     
         8 . A device in accordance with any of  claims 3  to  7 , wherein the third bridle ( 5 ) has two rolls ( 12 ,  13 ) with diameters (D 12 , D 13 ) that are the same as the diameters (D 11 , D 14 ) of the larger rolls ( 11 ,  14 ) of the second and fourth bridles ( 4 ,  6 ).  
     
     
         9 . A device in accordance with any of  claims 3  to  8 , wherein the first and fifth bridles ( 3 ,  7 ) each have two rolls ( 8 ,  9 ;  16 ,  17 ) with diameters (D 8 , D 9 ; D 16 , D 17 ) that are the same as the diameters (D 10 , D 15 ) of the smaller rolls ( 10 ,  15 ) of the second and fourth bridles ( 4 ,  6 ).  
     
     
         10 . A device in accordance with any of  claims 1  to  9 , wherein means ( 18 ) for measuring the tensile force present in the metal strip ( 2 ) are installed after the first bridle ( 3 ) in the direction of strip transport (R).  
     
     
         11 . A device in accordance with any of  claims 1  to  10 , wherein the second bridle ( 4 ) in the direction of strip transport (R) is equipped with means ( 19 ) for measuring the tensile force applied to the metal strip ( 2 ) by the rolls ( 10 ,  11 ).  
     
     
         12 . A device in accordance with any of  claims 3  to  10 , wherein the fourth bridle ( 6 ) in the direction of strip transport (R) is equipped with means ( 20 ) for measuring the tensile force applied to the metal strip ( 2 ) by the rolls ( 14 ,  15 ).  
     
     
         13 . A device in accordance with any of  claims 3  to  12 , wherein the fourth bridle ( 6 ) in the direction of strip transport (R) is equipped with measuring means ( 21 ) for measuring the speed of conveyance (v) of the metal strip ( 2 ), which means are connected with an open-loop or closed-loop control system ( 22 ), which regulates or automatically controls the drives of at least some of the bridles ( 3 ,  4 ,  5 ,  6 ,  7 ) according to the determined speed of conveyance (v).  
     
     
         14 . A method for operating a device ( 1 ) for the continuous stretcher leveling of metal strip ( 2 ), which device ( 1 ) has at least three bridles ( 3 ,  4 ,  5 ,  6 ,  7 ) in the direction of strip transport (R), with each bridle ( 3 ,  4 ,  5 ,  6 ,  7 ) having at least two rolls ( 8 ,  9 ;  10 ,  11 ;  12 ,  13 ;  14 ,  15 ;  16 ,  17 ), especially a device in accordance with any of  claims 1  to  13 , wherein, in the second bridle ( 4 ) in the strip transport direction (R), a tensile stress which is 96% to 100% of the yield point of the material of the metal strip ( 2 ) is built up in the metal strip ( 2 ).  
     
     
         15 . A method in accordance with  claim 14 , wherein, in a device with five bridles ( 3 ,  4 ,  5 ,  6 ,  7 ), a tensile stress which is greater than 100% of the yield point of the material of the metal strip ( 2 ) is built up in the metal strip ( 2 ) in the third bridle ( 5 ) in the direction of strip transport (R).  
     
     
         16 . A method in accordance with  claim 15 , wherein, in the fourth bridle ( 6 ) in the strip transport direction (R), a tensile stress which is 96% to 100% of the yield point of the material of the metal strip ( 2 ) is built up in the metal strip ( 2 ).  
     
     
         17 . A method in accordance with  claim 15 , wherein, in the fourth bridle ( 6 ) in the strip transport direction (R), a tensile stress which is greater than 100% of the yield point of the material of the metal strip ( 2 ) is built up in the metal strip ( 2 ).