Deep drawability of electron beam welded tailored blanks of commercially pure titanium thin sheets

Abstract

In this work, commercially pure titanium tailor-welded blanks (TWBs) were fabricated from sheets of thicknesses 1.0 mm (Ti1.0) and 1.2 mm (Ti1.2) using electron beam welding (EBW). It was observed that the titanium base materials had an equiaxed microstructure, whereas the FZ of the weld consisted of coarsened prior β  grains with internal α substructures. Transverse and longitudinal tensile tests were conducted to evaluate weld integrity and weld properties, respectively. The deep drawing behaviour of both the base materials and TWB had been investigated by conducting laboratory-scale deep drawing tests. The limiting drawing ratios (LDR) of the Ti1.0 and Ti1.2 base materials were 2.14 and 2.21, respectively. The LDR of TWB was 2.14, which was same as that of the Ti1.0 base material. The CPB06 yield criterion and weld properties were incorporated in the FE modelling to study the deep drawing behaviour of the TWB for the first time. The FE model successfully predicted the non-uniform material flow and thickness distribution in the deep drawn TWB. Moreover, the weld line movement was found to be towards the Ti1.0 side at the cup top region and towards the Ti1.2 side at the cup bottom of the TWB deep-drawn cup.