Reverse deep drawability of 5A06 aluminum alloy plate at elevated temperatures

In order to avoid the occurrence of fracture at room temperature in reverse deep drawing of aluminum alloy plate, the warm reverse deep drawing method was proposed. The experiments were conducted at room temperature, 280 and 360 °C with a 4.5 mm thick 5A06 aluminum alloy plate. The effect of temperature, blank-holding force and gap on the fracture and wrinkle of the reverse deep drawing process was investigated. A fully coupled thermal-mechanical simulation was carried out to obtain the stress distribution through the commercial software of Abaqus/Explicit. The results show that the fracture is avoided at 280 °C since the bending-induced stress gradient in the transient area between the inside corner and the straight wall decreases from 505 MPa at RT to 72 MPa at 280 °C. Although the fracture is avoided as the temperature increases, the wrinkle occurs at the outside die corner at temperature over 280 °C, where the circumferential compressive stress becomes larger than that at the inside. As the temperature increases to 360 °C, the fracture occurs due to the excessive softening, the tensile stress in the straight wall reaches rapidly to the tensile strength at the beginning of reverse deep drawing. When 1.5t (t=4.5 mm) blank holding gap is applied at 280 °C, both the fracture and wrinkle can be avoided, and 420 mm deep cups are drawn successfully.