Method for pre-shaping sheet metal, and computer program and device for carrying out the method

Abstract

The disclosure relates to a method for pre-shaping sheet metal ( 1 ) in strip- or panel-form having a flat cross-sectional profile into a circular arc-shaped cross-sectional profile, in a pre-shaping section ( 3 ) of a plant for producing open-seam pipes. The circular arc-shaped cross-sectional profile is provided to the sheet metal ( 1 ) in the pre-shaping section ( 3 ) by means of roll profiling in a plurality of successive bending steps in a transport direction. The cross-sectional profile is created by step-by-step bending of individual circular arc portions ( 8 ) from an outer edge of the sheet metal ( 1 ) toward a center line ( 7 ) such that the individual circular arc portions ( 8 ) directly adjoin one another or at least partially overlap. The disclosure further relates to a device for carrying out the method.

1 .- 19 . (canceled) 
     
     
         20 . A method for pre-shaping sheet metal ( 1 ) in strip form or panel form having a flat cross-sectional profile into a circular arc-shaped or approximately circular arc-shaped cross-sectional profile in a pre-shaping section ( 3 ) of a plant for producing open-seam pipes, the method comprising:
 roll profiling the sheet metal ( 1 ) in the pre-shaping section ( 3 ), in a plurality of bending steps following one another in a transport direction, to provide the circular arc-shaped or approximately circular arc-shaped cross-sectional profile,   wherein the circular arc-shaped or approximately circular arc-shaped cross-sectional profile is created by step-by-step bending of individual circular arc portions ( 8 ) from an outer edge of the sheet metal ( 1 ) toward a center line ( 7 ) such that the individual circular arc portions ( 8 ) directly adjoin one another or at least partially overlap.   
     
     
         21 . The method according to  claim 20 ,
 wherein the individual circular arc portions ( 8 ) are generated symmetrically toward the center line ( 7 ), starting from both outer edges ( 6 ) extending in the transport direction of the sheet metal ( 1 ).   
     
     
         22 . The method according to  claim 20 ,
 wherein the circular arc-shaped cross-sectional profile is generated by a plurality of rolls in a plurality of rolling mill stands ( 5 ) arranged one behind the other.   
     
     
         23 . The method according to  claim 20 ,
 wherein the circular arc-shaped cross-sectional profile is generated in a continuous pass of the sheet metal ( 1 ) through rolling mill stands ( 5 ) arranged one behind the other in the pre-shaping section ( 3 ).   
     
     
         24 . The method according to  claim 20 ,
 wherein the circular arc portions ( 8 ) have the same bending radius.   
     
     
         25 . The method according to  claim 20 ,
 wherein a bending radius of the circular arc portions ( 8 ) is selected to be greater than or equal to a desired target radius of the sheet metal ( 1 ).   
     
     
         26 . The method according to  claim 20 ,
 wherein a bending radius with respect to a desired target radius is determined using a software-supported springback calculation.   
     
     
         27 . The method according to  claim 20 ,
 wherein the sheet metal ( 1 ) is subjected to three-point deformation at each bending step from each outer edge ( 6 ) symmetrical to the center line.   
     
     
         28 . The method according to  claim 27 ,
 wherein the three-point deformation is generated with a roll configuration with which a bending radius is generated on an inside of the circular arc portion ( 8 ) to be formed with one support and on an outside of the circular arc portion ( 8 ) to be formed with two supports.   
     
     
         29 . The method according to  claim 25 ,
 wherein at least one radius and/or one angle of attack of at least one roll and/or at least one roll configuration with respect to a desired target radius is calculated by a computer as a function of a springback calculation and taking into account a height and/or width of a roll gap.   
     
     
         30 . The method according to  claim 29 ,
 wherein at least one roll is selected from a list with a plurality of rolls having different radii in a given gradation as a function of a result of the calculation by a computer program.   
     
     
         31 . A computer program comprising instructions that, when the program is executed by a computer, cause the computer to execute the method according to  claim 29 . 
     
     
         32 . A device for pre-shaping sheet metal ( 1 ) in strip form or panel form having a flat cross-sectional profile into a circular arc-shaped cross-sectional profile in a plant for producing open-seam pipes, comprising:
 a plurality of rolling mill stands ( 5 ) arranged one behind the other with respect to a pre-shaping section ( 3 ), in each case with a roll configuration that is designed in such a manner that a bending radius is provided to the sheet metal ( 1 ) in a plurality of profile sequences starting from each outer edge ( 6 ), symmetrically with respect to a center line ( 7 ) of the pre-shaping section ( 6 ).   
     
     
         33 . The device according to  claim 32 ,
 wherein the rolls of at least one rolling mill stand ( 5 ) are designed in such a manner that the sheet metal ( 1 ) is bent with one support on an inside of a circular arc portion ( 8 ) to be formed and with two supports on an outside of the circular arc portion ( 8 ) to be formed.   
     
     
         34 . The device according to  claim 32 ,
 wherein the rolls of rolling mill stands ( 5 ) arranged one behind the other are arranged differently and/or have different radii and/or different roll profiles.   
     
     
         35 . The device according to  claim 32 ,
 wherein at least one rolling mill stand ( 5 ) has at least one top roll ( 9 ), one bottom roll ( 10 ) and one bending roll ( 11 ) on both sides of the center line ( 7 ), each forming a three-point support.   
     
     
         36 . The device according to  claim 32 ,
 wherein at least one rolling mill stand ( 5 ) comprises at least one top roll ( 9 ) and one bending roll ( 10 ) on both sides of the center line ( 7 ) and a single bottom roll ( 10 ) extending on both sides of the center line.   
     
     
         37 . The device according to  claim 32 ,
 wherein at least one rolling mill stand ( 5 ) comprises at least one top roll ( 9 ) and one bottom roll ( 12 ) on both sides of the center line ( 7 ),   wherein the bottom roll has a roll profile that forms two supports.   
     
     
         38 . The device according to  claim 32 ,
 wherein a distance and/or an angle of attack of the rolls is adjustable with respect to the center line ( 7 ).