Method of making a flanged tubular metallic part

A method of making a flanged tubular metallic part by cold forging, comprising:

• a step of preparing a cylindrical blank;
• a step of heating the blank to a predetermined temperature;
• a depression forming step of forming an axial depression that is concentric and cylindrical, in the blank:
• a step of preparing a flange forming die assembly including an inner punch, an annular outer punch disposed concentrically around the inner punch so as to provide a predetermined space therebetween, a die having a cylindrical hole surrounding the outer punch and a counter punch unit disposed opposite to the inner punch and cooperating with the outer punch and the die so as to define an annular cavity for forming an annular flange, and
• a flange forming step of forming, by using the flange forming die assembly, the blank into an intermediate product having the flange on an outer circumferential surface thereof;
• wherein assuming that the direction in which the inner punch is moved for subjecting the blank to the flange forming step is referred to as forward, the flange forming step includes moving the inner punch axially into the depression so as to cause a leading end of the inner punch to be positioned more forward than a backward side surface of the flange thereby causing a metal of the blank to flow radially outward into the cavity to form the flange and axially backward to form, in the space between the inner punch and the outer punch and by backward extrusion, a concentric sleeve portion that is positioned backward of the flange while allowing the outer punch to be yieldingly urged against the backward side surface of the flange during formation of the flange within the cavity.