In order to improve quarter waves occurred in the wide and thin gauged
alloy steel rolled by 20-high sendzimir mill, a computer simulation b
ased on the divided element method and an actual cold rolling experime
nt were carried out. Quarter waves were simulated by elastic deformati
on analysis of rolls considering bending deformation of back up rolls
and the effect of control actuators on controllability of quarter wave
s were analyzed. Computer simulation showed that control actuators suc
h as shifting of the 1st intermediate roll and crown adjustment of As-
U-Roll in back up rolls were not effective to control quarter waves an
d that changing taper mode (both length and magnitude) at the barrel-e
nd taper radius of the 1st intermediate roll was rather very effective
. From an actual rolling experiment it was verified that quarter waves
could be reduced remarkerably by changing taper mode of the 1st inter
mediate roll.