INVESTIGATION ON FORMABILITY OF TAILOR WELDED BLANKS PREPARED BY FRICTION STIR WELDING PROCESS

Abstract

Tailored Welded Blank (TWB) is prepared by welding two or more blanks having same or different thickness of different mechanical properties or coatings in a single plane prior to forming. Welding can be performed as per manufacturer choice. In this project Friction Stir Welding process has been chosen to weld the Aluminium blank. Aluminium alloys that have been used for the preparation of TWBs are AA5083 and AA6082, both having same thickness. After the fabrication of TWBs, testing has been performed on the specimens to check the mechanical properties of the welded blank Tensile properties, formability of the sheet has been recorded and modelling and simulation has been carried out to predict the formability of the Tailor Welded blanks. Low density and high specific energy absorption performance and good specific strength are its most important properties. Aluminium is also resistant to corrosion and can be recycled to its pure form. To prepare a TWB, it is quite cumbersome to weld Aluminium blanks by conventional welding processes. Friction stir welding (FSW) came with the solution regarding joining aluminium alloys as a solid-state joining process. Noor Zaman Khan et all. 2017 had studied the mechanical and microstructural behaviour of friction stir welded similar and dissimilar blanks of different aluminium alloys, reveals high hardness due to grain refinement at the stirring zone with a sustainable joint efficiency. The FSW process incorporates joining by material locking due to its stirring mechanism. FSW, being a solid-state joining process, avoids the various defects due to formation of porosity, blow holes, poor solidification etc. The excessive plastic deformation at elevated temperature during FSW produces equiaxed recrystallized grains which are responsible for the higher strength and lower formability of the weld zone. To enhance the formability of the Tailor Welded Blanks, warm forming is a better option.