Process for rolling flat material and strip

A process for rolling a roll material in a roll stand, the roll stand having work rolls and support rolls and devices for balancing the work rolls and positively and negatively bending the work rolls mounted in chucks of the work rolls, the devices including vertically arranged piston-cylinder units resting bilaterally on the roll stand and arranged from above and below against projections embodied on the chucks of the work rolls and extending toward a housing window of the roll stand, the piston-cylinder units being pressurizable for moving the chucks toward or away from each other, said process comprising the steps of:

• a) setting a balancing force using the piston-cylinder units for positive and negative roll bending by moving the work rolls against the support rolls without clearance when the roll gap between the work rolls is open and empty;
• b) setting a negative roll bending force by setting the pressure in the piston-cylinder units for negative bending to attain the roll gap correction needed under load to control the profile and flatness of a roll material;
• c) setting a positive roll bending force by setting the pressure in the piston-cylinder units for balancing and positive bending higher than the required balancing force;
• d) controlling the piston-cylinder units for positive and negative bending such that a roll force comprising the negative roll bending force set in step b. and the positive roll bending force set in step c. is exerted on the work rolls when the roll material is inserted in the roll gap and expands the roll gap to a desired size;
• and
• e) controlling the piston-cylinder units for positive and negative bending such that the required balancing force set in step a. is exerted on the work rolls when the end of the roll material exits the roll gap.