Abstract: A method of providing a member having a metal core with a nonferrous coating wherein the metal core affords strength and rigidity while the nonferrous outer coating, or cladding, provides a non-corrodible surface and wherein the cladding is of such uniform thickness that final forming of the member may be performed without penetrating or breaking the coating, or exposing the core. The cladding is applied by extruding the nonferrous material in a cross-axis die where it reaches a plastic state and passing the metal core through the plastic non-ferrous metal in the die with the high extrusion pressure creating heat to render the nonferrous metal in a plastic state and further extruding the nonferrous metal around the metal core as it exits from the die, whereby to obtain a wrought structure of the clad coating, without reducing the cross-sectional area of the core during the extrusion operations.

Abstract: An improved extrusion process and apparatus for extruding feedstock is disclosed in which the gripping force for the extrusion is derived by forcing the feedstock into a passageway to develop in the feedstock on two opposing surfaces a pressure of at least the yield strength of the feedstock and moving the feedstock toward a stop and die means located at the end of a passageway and particularly that improvement consisting of providing a fork-shaped element that forms the passageway with a distance between the constraining walls sufficiently greater than the height of the wall surfaces so that no lubrication of the ungripped surfaces of the feedstock is required.