Electromagnetically forming a tubular workpiece

Abstract

A process is provided for electromagnetically forming an elongated tubular workpiece by applying an electromagnetic force provided by an energized workcoil to the workpiece radially of its longitudinal axis and by simultaneously applying an axial compressive force to the workpiece. The axial compressive force may be applied to the workpiece from a time before applying the radial electromagnetic force. A forming member including a surface having a desired contour is provided adjacent the workpiece and the workpiece is caused by the electromagnetic force to conformingly engage the surface of the forming member and thereby assume the contoured shape of the forming member. The forming member may be a forming die which surrounds the workpiece or a forming mandrel may be positioned within the workpiece. In another embodiment, both a forming die and a forming mandrel may be employed for performing the forming operation at longitudinally spaced regions of the workpiece. The axial compressive force may be applied to the workpiece at one or both ends by positioning in engagement with an end of the workpiece one surface of a plate member of electrically conductive material, the plate member lying in a plane transverse of the longitudinal axis of the workpiece, and positioning adjacent to but electrically isolated from a second surface of the plate member a flat electrically conductive coil, then energizing the coil to create a force directed against the plate member to thereby compress the workpiece between its ends.