Formability Improvement For TWB Using Drawbead Design

In recent years the use of tailor-welded blanks (TWB) has grown significantly, but there still exists serious concern on the poor formability in the stamping of TWB, which is commonly considered to relate to the uncertainty in the weld line movement. This paper proposes a drawbead design methodology to achieve weld line movement control. Based on the properties, geometries and frictions of base-metals constituting the TWB, the magnitudes and ratio of drawbead restraining force (DBRF) between the two sides of the base metal sheets across the weld line, which is the function of drawbead depth, can be determined for minimizing the weld-line movement and enhancing TWB formability. In the case of 2D strip drawing with TWB, lower restraining force should be used in the side of thicker base metal to reduce weld line movement. Computer simulations and experiments were conducted to verify the weld line movement control strategy and the drawbead design, and to demonstrate the formability improvement.