Seat frame assembly for a motor vehicle

A seat frame assembly for a motor vehicle comprises a seat frame (14) and a seat back frame (16). The seat frame is constructed and arranged to have a seat cushion (30) mounted thereon in overlying relation. The seat back frame (16) is connected with the seat frame (14) and has a pair of spaced metallic vertical support portions (34) at opposite sides thereof, the seat back frame being constructed and arranged to have a seat back cushion (32) mounted thereon. At least one of the vertical support portions is formed from a pair of telescoping tubular blanks including an elongated inner metal blank (300) formed into an integrally formed vertical member (36) of the at least one vertical portion extending from a lower portion of the seat back frame connected with the seat frame to an upper end of the seat back frame and a relatively shorter outer metal blank (320) formed into a sleeve (46) rigidly secured in surrounding relation to the lower portion of the vertical support member (36). The outer blank and inner blank are formed into the sleeve and the vertical member respectively during a hydroforming process in which the inner blank is expanded so that an outer surface (324) thereof is moved into peripheral contact with an inner surface (322) of the outer blank, and the inner blank and the outer blank are expanded into peripheral contact with die surfaces (310) defining the exterior surfaces of the one vertical support portion (36).