In a pair crossed rolling mill developed as a new system capable of co
ntrolling strip crown, frictional forces act from the rolls to the str
ip in the strip width direction because the roll axes cross each other
. Even in the case where some rolling conditions, such as lubrication,
roll speed, and crossangle, differ for the upper and lower strip surf
aces, the slip direction between the rolls and the strip changes on bo
th surfaces owing to shear deformation occurring in the strip, so the
frictional forces in the width direction acting on both surfaces becom
e equal to each other and, thus, equilibrium is maintained. Although t
here is an allowable limit for the difference in the above rolling con
ditions for the upper and lower surfaces, the stable range is sufficie
ntly wide and that stable rolling, without walking, is guaranteed in p
ractice.