An experimental investigation of the drawability of AA6082 sheet under different elevated temperature forming processes

The performed research has, for the first time, investigated and compared the drawability of AA6082 at a comparable temperature range between two elevated temperature forming processes: termed (i) Low Temperature Hot Form and Quench (LT-HFQ (R)) or pre-cooled HFQ (R), patented by Adam et al. (2015) and (ii) Direct Heating Aluminium Forming (DHAF) which represents a refinement of conventional warm forming targeting a higher temperature range. A series of uniaxial tensile and cylindrical deep drawing experiments were conducted. According to uniaxial tensile test results, the most obvious work-hardening and reasonable ductility was observed under LT-HFQ (R) at a deformation temperature of 350 degrees C and strain rate of 1s(-1), which can enhance drawability. For deep drawing experiments, it was found that preheating conditions of each process prior to forming significantly affected forming characteristics and post-formed hardness of the alloy; both the achieved maximum Draw ratio (DR) and limit Blank Holding Force (BHF) at some specific process parameters were increased under LT-HFQ (R). Forming speed and temperature had significant effects on alloy deformation and thus drawability for both processes. In addition, by evaluating the post-formed hardness, process drawability and microstructural evolutions under different processes were simultaneously analyzed.