An automated system for exchanging components of a continuous seam-welded tube mill to change from production of one tubular product to another. The components to be changed are mounted upon subbase units adapted to be removably affixed to a fixed mill base. Alternate sets of changeable mill units mounted on duplicate subbase sections are provided for off line tooling change and setup. Changeover modules are automatically conveyed from a tooling storage area to the mill base for automatic changeover. Push-pull units are incorporated in the changeover modules to shift the subbase sections from the mill base to the changeover module and the previously retooled duplicate subbase sections from the changeover modules into operative position on the mill bases.