THE AVOIDANCE OF DEFECTS IN RADIALLY EXTRUDED TUBULAR PARTS BY PREFORMING

The production of sound tubular hanged parts by conventional radial ex trusion is normally limited to components having a low ratio between t he thickness of the flange and the initial wall thickness of the tube. In order to enable an extension of this formability limit the present paper presents an alternative radial extrusion technique introducing a preforming stage. The theoretical background for the development of the process and preform die design was accomplished through a comprehe nsive analysis using the finite-element method. Experiments carried ou t at room temperature in EICM aluminum show good agreement with comput ed predictions and confirm the advantages of the proposed technique. ( C) 1997 Elsevier Science S.A.