Abstract: A system for forming tubular metal products from tubular workpieces by hydroforming achieving single-step radial expansion of 70-150% with high dimensional accuracy. Enhanced single-step radial expansion is achieved by maintaining a predetermined functional relationship among the driving parameters of the hydroforming process and by increasing the plasticity of the workpiece by employing the fractional deformation effect and by applying ultrasound oscillations and alternating angular strains to the workpiece.

Abstract: A method and a device for forming a metal billet into an elongated product body of desired cross-sectional shape and dimension by a combination of die drawing and hydroextrusion from a pressure chamber having a central axis, holding a pressurized working liquid and being fitted with a hydroextrusion die, which are characterized by placing a drawing die of smaller cross-sectional size than the hydroextrusion die in coaxial alignment with the latter at a distance L downstream therefrom whereby the hydroextrusion die and the drawing die form a pair of dies flanking an intermediary empty region; adjusting the distance L to fit the metal and size of the elongated product body such that any stretch of an extruded body passing through the intermediary empty region retains its elastic stability; continuously extruding the billet through the hydroextrusion die to form an extruded intermediate product; continuously passing the extruded intermediate product across the intermediary empty region into the drawing die; and