Patent ID: 6672119
Filing Date: 2004-01-06
Classification: B21B

Abstract:
A method of rolling a structural shape in a caliber roll mill having a caliber-roll pair including upper and lower caliber rolls journaled at opposite ends in respective mill-stand frames of a mill stand with respective bearing chocks, corresponding ends of said rolls being located at a service side of said mill stand and at a drive side of said mill stand at which said rolls are driven, said rolls having respective juxtaposed rolling calibers generating axial forces on said rolls upon rolling a structural shape between them and axially engageable faces flanking said rolling calibers, one of said rolls being axially shiftable relative to said other of said rolls, said method comprising said steps of:rolling a structural shape between said rolling calibers to size said rolled structural shape; and axially positioning said rolls relatively by: (a) shifting said one of said rolls axially in one axial direction to press said axially engageable faces on one side of said rolling calibers against each other and shifting said one of said rolls axially in an opposite axial direction to press said axially engageable faces on another side of said rolling calibers against each other with a defined force, (b) storing values representing said positions of said one of said rolls upon axial engagement of said faces on each side of said rolling calibers with each other, a value of said axial stroke of said one of said rolls between engagements of said engageable faces on opposite sides of said rolling calibers, and a calculated mean position of said one of said rolls, and shifting said one of said rolls into a caliber-registering position of said rolls of said pair; (c) then shifting said one of said rolls axially in one axial direction to press said axially engageable faces on one side of said rolling calibers against each other and shifting said one of said rolls axially in an opposite axial direction to press said axially engageable faces on another side of said rolling calibers against each other with incrementally increased forces, and storing respective values of said respective forces, respective values representing said positions of the one of said rolls upon axial engagement of said faces on each side of said rolling calibers with each other at said incrementally increased forces and values of said axial stroke of said one of said rolls between engagements of said engageable faces on opposite sides of said rolling calibers for said incrementally increased forces, and calculating from said stored values a relationship between spring constants of said frames with axial force on said rolls; and (d) during rolling of said structural shape shifting said one of said rolls out of said caliber-registering position by an amount calculated from the spring response of said frames to an expected axial force to be developed during rolling into an actual rolling position, and maintaining said one of said rolls in said actual rolling position with a position controller.