Mill for producing strip and use thereof

A mill for producing a continuous strip comprising:

• a roll stand;
• inner rollers including a pair of upper and lower work rollers rotatably mounted on the roll stand at opposite ends thereof to receive a metallic material under rolling pressure to form the strip;
• means provided in the roll stand for exerting a rolling force against the work rollers to produce the rolling pressure;
• means for bending neck portions of the pair of work rollers provided in the roll stand at opposite ends thereof;
• at least one local back-up roller each being positioned upper or lower relative to the strip as an outermost roller mounted on the roll stand at opposite ends thereof and having means for defining a surface in contact with an adjacent inner work roller, said surface consisting essentially of a pair of rotatable and axially movable surface sections fixed at a constant radial distance from the axis of the local back-up roller and axially arranged to have a back-up effect on the adjacent work roller at two local areas thereof;
• and means in the local back-up roller for drivably moving each contact surface section axially relative to the adjacent work roller
• wherein each local back-up roller has a main shaft and a pair of back-up devices, each back-up device comprising:
• a support roller rotatably and coaxially mounted on the main shaft;
• a housing axially holding the support roller, a threaded shaft axially screwed into the housing;
• and means for rotating the threaded shaft to thereby adjust an axial position of the support roller, the support roller provides said contact surface sections of each local back-up roller,
• wherein the main shaft is axially and rotatably fixed and the support rollers are rotated relative to the main shaft via bearing means.

A method of producing a strip comprising:

• (i) providing a mill comprising a roll stand;
• inner rollers including a pair of upper and lower work rollers rotatably mounted on the roll stand at opposite ends thereof to receive a metallic material under rolling pressure to form the strip;
• means provided in the roll stand for exerting a rolling force against the work rollers to produce the rolling pressure;
• means for bending neck portions of the pair of work rollers provided in the roll stand at opposite ends thereof;
• at least one local back-up roller each being positioned upper or lower relative to the strip as an outermost roller mounted on the roll stand at opposite ends thereof and having means for defining a surface in contact with an adjacent inner work roller, said surface consisting essentially of a pair of rotatable and axially movable surface sections fixed at a constant radial distance from the axis of the local back-up roller and axially arranged to have a back-up effect on the adjacent work roller at two local areas thereof;
• and means in the local back-up roller for drivably moving each contact surface section axially relative to the adjacent work roller
• wherein each local back-up roller has a main shaft and a pair of back-up devices, each device comprising:
• a support roller rotatably and coaxially mounted on the main shaft;
• a housing axially holding the support roller, a threaded shaft axially screwed into the housing;
• and means for rotating the threaded shaft to thereby adjust an axial position of the support roller, the support roller provides said contact surface sections of each local back-up roller,
• wherein the main shaft is axially and rotatably fixed and the support rollers are rotated relative to the main shaft via bearing means;
• and
• (ii) adjusting the axial positions of the contact surface sections of each local back-up roller, feeding a metallic material between said upper and lower work rollers and controlling the roller bending means in response to a profile of the strip.

A method of producing a strip comprising:

• (i) providing a mill comprising a roll stand;
• inner rollers including a pair of upper and lower work rollers rotatably mounted on the roll stand at opposite ends thereof to receive a metallic material under rolling pressure to form the strip;
• means provided in the roll stand for exerting a rolling force against the work rollers to produce the rolling pressure;
• means for bending neck portions of the pair of work rollers provided in the roll stand at opposite ends thereof;
• at least one local back-up roller each being positioned upper or lower relative to the strip as an outermost roller mounted on the roll stand at opposite ends thereof and having means for defining a surface in contact with an adjacent inner work roller, said surface consisting essentially of a pair of separate surface sections, each section being movable coaxially relative to the axis of the local back-up roller involved and rotatable thereabout and being fixed at a constant radial distance from said axis at any axial position where the section is allowed to move, both sections being axially arranged to have a back-up effect on said adjacent inner work roller at two local areas thereof;
• and means in each local back-up roller for drivably moving each contact surface section axially relative to the adjacent inner work roller and relative to each other between a position wherein the contact surface sections are in contact with each other and a position where the contact surface sections are spaced apart from each other at a predetermined maximum axial length;
• and
• (ii) adjusting the axial positions of the contact surface sections of each local back-up roller, feeding a metallic material between said upper and lower work rollers and controlling the roller bending means in response to a profile of the strip.