Combined temperature and blank holder pressure control in forming of aluminum of tailor-welded blanks

Tailor-welded blanks, although being manufactured since late 60's have attracted special attention since early 90's. Automotive industry is the main driver behind the use of tailor-welded blanks. Increasing fuel prices and stringent emissions norms have forced automakers to innovate new methods to reduce vehicle mass. Use of aluminum tailor-welded blanks for BIW structural components is one way to achieve this target. This work focuses on some of the main issues behind stamping of aluminum tailor-welded blanks and proposes new methodology to address them.;In the past, investigators have had some success in studying and improving the formability of aluminum tailor-welded blanks. This study investigates another possible method to form aluminum tailor-welded blank using combined temperature and blank-holder pressure control. This work simulates the most common process of deep-drawing of circular cup made from an aluminum tailor-welded blank. Simulation results and previous literature indicate that the weld-line movement towards the stronger material in the die cavity causes failure in most tailor-welded blanks. The failure appears in the form of a crack adjacent to the weld-line in the thinner blank. The method proposed in this work is based on the fact that yield strength of aluminum alloy significantly reduces at warm temperatures in the range of 250-300°C. Heating the thicker blank enhances the metal flow in the die cavity, which contributes in reducing the weld-line movement. Along with this, by reducing the blank-holding pressure on the thicker blank with respect to the thinner blank ensures that the thicker blank flows well in the die cavity.;In this work, FEA simulations are carried out to investigate the weld-line movement under various temperature distributions and blank-holding pressures. ABAQUS, a commercially available FE program has been used to perform thermal and plastic rate-dependent analysis of the 5XXX aluminum alloy blank. It is observed that heating the thick blank to warm temperatures significantly contributes to the reduction in weld-line movement. A response surface and regression equation indicates the region of optimum setting of the two parameters.