Shape Controllability in New 6-High Mill (UC-4 Mill) with Small Diameter Work Rolls.

The work roll diameter of a new 6-high mill (UC-4 mill) is as small as that of cluster type mills. Shape control flexibility and the ability to roll flat strips in the UC-4 mill were examined experimentally and analytically, and it was found that the mill was suitable for thin strip rolling of stainless steel or other hard materials. The roll configuration of the UC-4 mill is asymmetrical in the longitudinal direction. Effects of this asymmetricity on shape control characteristics were also studied, and it was found that the shape controllability did not change with rolling direction. A cross buckle becomes a problem when thin and hard strips are rolled with small diameter work rolls. In the UC-4 mill, however, the occurrence of cross buckles did not increase despite of the smallness of the work roll diameter. Three actual plants are presently in production.