Analysis of Temperature and Stress in Differential Temperature Reverse Deep Drawing of 5A06 Aluminum Cup

The warm reverse deep drawing process is proposed to form cylindrical cups with greater drawing depths. Experimental and numerical investigations were conducted to analyze the effect of the temperature field on the drawing depth limit and the stress distribution during the warm reverse deep drawing process of a 5A06 aluminum plate. The effects of the punch temperature and initial flange temperature on the temperature gradient in the blank are discussed. The drawing depth limits for the different temperature gradients in the blank were determined. In addition, the effect of the temperature field on the radial stress distribution was analyzed. A 180A degrees C temperature gradient occurs when the punch temperature is room temperature. When the temperature field generated in the blank is uniform, a fracture occurs, and the drawing depth limit (72 mm) is only 20% of the desired depth. When the temperature gradient is 100A degrees C, the drawing depth limit increases by 400%. Fracture occurs for a uniform temperature field because the radial stresses at the inside corner are larger than those at the punch corner. As the temperature gradient increases, the radial stress at the inside corner is lower than that at the punch corner, which prevents fracture. A deep cup with a 375-mm drawing depth was produced when the temperature gradient exceeded 100A degrees C.