Abstract: A method is provided for controlling interstand tension by roll gap adjustment to reduce gage variations caused by unplanned rolling velocity changes wherein a signal proportional to the tension changes produced by deviations from the desired speed ratio of adjacent stands is used to modify the conventional tension error signal before the latter signal is used to control roll gap thereby discriminating between tension changes caused by mill stand or strip physical changes, which it corrects, and tension changes caused by unplanned speed disturbances, which it ignores instead of maintaining constant tension. The resulting system exhibits improved tolerance for imperfect stand speed control.

Abstract: A method for controlling metal strip thickness in a multi-stand rolling mill is provided which employs feed forward control to adjust the main drive armature current at the upstream mill stand when strip thickness data arrives at the downstream mill stand, establishes a control signal representing the desired speed of the first stand as a function of the second stand's measured speed, the strip thickness measurements, and the scheduled speeds of the first and second stands, develops an armature current reference modifier which is added to the current reference developed by the conventional speed regulator and thereby improves gage control by reducing the response time for upstream stand speed changes and by correcting upstream stand speed for unplanned changes in downstream stand speed.