Cryogenic deep drawing of aluminum alloy AA6014 using macro-structured tools

For functional lightweight construction, 6xxx aluminum alloys are essential materials for exterior components due to their low weight to stiffness ratio and acceptable formability. The formability of the 6xxx alloys is lower compared to other aluminum alloys but they are free of flow lines. MOUSAVI ET AL. [1] demonstrate an alternative method of improving the forming limit with a deep drawing process using macro-structured tools. Another approach increasing the formability of aluminum alloys is forming at cryogenic temperatures [2]. This paper presents an advancement of deep drawing on macro-structured tools at cryogenic temperatures. This assumes a lower heat flux due to the reduction of the contact area between the blank and deep drawing tools, enabling forming at cryogenic blank temperature. After characterization of the material, experimental investigations are carried out on a cup test geometry. In addition to the required punch force at different temperatures, this paper presents the influence of macro-structured tools at cryogenic temperatures on springback and hardness distribution. Finally, the extension of the process limits and options by cryogenic macro-structured deep drawing are discussed.