The purpose of the present invention is to propose a new way of
manufacturing curved metal tubes or rods with arbitrary sections and
eliminating the conventional bending defects such as thinning and
thickening in the wall of tube, distortion of the section, and wrinkling
and folding on the surface by the extrusion bending process that can
extrude and weld together one or more billets inside dies cavity, and can
bend them during extrusion due to the gradient of extrusion velocities
controlled by the eccentricity of the cavity sections between the
entrance and the exit of the eccentric conical extrusion bending dies and
conical plug, or by the relative size of the holes of multi-hole
container, or by the relative moving velocity of multi-punches.