ABSTRACT
This Chapter discusses the design of rolls, their manufacture, the techniques used for finishing and reconditioning and their bearings, primarily as pertaining to four-high mills. It also discusses stresses retained in the rolls after fabrication and stresses impressed into the rolls under mill use are treated insofar as they affect roll life and the longitudinal bending of the rolls. Rolls are usually cast slightly oversize to provide stock for subsequent machining and thereby permit defects on the cast roll surface to be conveniently removed. However, the amount of excess metal on the rough casting must be limited, since the necessity for removing a considerable thickness of the metal would seriously diminish the thickness of the hardened layer produced either by casting or heat treatment. In mill design, the barrel length of the mill rolls is established by the maximum width of strip to be rolled, the mill width being usually a few inches greater than the maximum strip width.
