Formability Enhancement of Galvanized IF-Steel TWB by Modification of Forming Parameters

Tailor-welded blanks (TWBs) have numerous advantages over traditional blanks used in manufacturing, such as energy conservation and environment protection. Low formability and weld line movement during forming operation are main limitations of these blanks. In this research, the effects of forming parameters including thickness ratio (TR), rolling direction with respect to the weld line and direction of major stress with respect to the weld line, on formability and weld line movement of TWBs made of galvanized Interstitial-Free (IF) steel were investigated experimentally. Also the effect of application of non-uniform blankholder force on weld line movement was studied by FEM simulation. By utilization of ABAQUS software, blankholders with different geometries, namely one-piece and two-pieces were modeled and forming process was simulated. The results revealed that formability maximized when the major stress and rolling direction were along the weld line. The results showed applying different blankholder forces, by application of the two-pieces blankholder, leads to more uniform strain distribution and correspondingly less weld line movement in TWBs with TR greater than 1. It was also concluded that the effect of geometric discontinuities on reducing formability was greater than the effect of the weld region.