Increasing Performances by Using Multi-Thicknesses Blanks

Multi-thickness blanks (MTB) enable the dimensional optimization of steel parts by modulating thickness and mechanical properties. Traditionally, this is done by the addition of reinforcement to the basic part after the drawing of both. With MTBs, we first assemble the two flat blanks to obtain a single blank, which is then drawn without further assembly. MTBs comprise the Tailored Welded Blank (TWB), already widely used in automobiles, and a new category “Patchwork”. The TWB is a butt-welded assembly of two blanks with neither overlap nor superimposition. The patchwork blank is made by either the adhesive bonding or welding of a blank onto the surface of the base blank, at the point to be reinforced. These products enable the increase of performance objectives (impact, rigidity, vibration and fatigue resistance, etc.) whilst permitting weight reduction and thus adding to the potential of high resistance steels. They also enable, in numerous cases, the reduction of overall costs. Examples of applications are; side members, shock towers and pillar reinforcements. Illustration of design principles permitting the better understanding and exploitation of MTB potential are shown in this paper.