Roll and mandrel profiles for cold pilger rolling mills - where both profiles have convex zones blending into concave zones in middle of working length of mandrel

摘要

Both the longitudinal curve of the mandrel periphery, and the developed view of the base of the groove in the rolls, possess a convex curvature at the inlet side of the mill. The convex curvature blends into a concave curvature at a point at the middle of the working length of the mandrel. One pref. mandrel has a longitudinal profile following an arc-cotangent function on which a line located at an angle to the mandrel axis is superimposed. The advantage of the invention is that the longitudinal stresses imposed on the rolls are reduced, and therefore rolling speeds can be increased.