Investigation On Reverse Hydro-drawing Of 5A06 Alluminum Alloy Sheet

The use of high strength steel plates, tailor welded blanks, light alloys, composite materials, and hollow structures is the main means of realizing lightweight structures of the aviation, aerospace and automotive industry. Using aluminum, titanium and other lightweight materials is an important way to achieve the lightweight structures from the view of material. Many typical sheet parts are made of alumite alloy and high-strength aluminum alloy. However, the low plasticity of aluminum alloy and other lightweight materials is the bottleneck of sheet metal forming. Therefore, hydromechanical deep drawing, which can improve the forming limit of material, is an effective approach for sheet metal with low plasticity, in hard to form materials such as aluminum alloy.In this paper, aimed at the cylindrical cups with hemispherical bottom and flat bottom, large height-diameter ratio, by numerical simulation and experiments, investigation were performed on the effects of parameters on hydromechanical deep drawing of cylindrical cups with hemispherical bottom and flat bottom.The dynamic explicit analytical software ETA/Dynaform5.5 was used, which is based on LS-DYNA3D. Hydromechanical deep drawing and reverse drawing of 5A06 aluminum alloy were simulated. Effects of chamber pressure, blank holding gap, initial hydraulic pressure and blank holding force on the thickness distribution of cylindrical cup were studied, and then typical defects were analyzed during the process of cylindrical cup hydromechanical deep drawing and reverse drawing. Finally, the stress and strain distribution was respectively researched during the process of hydromechanical deep drawing and reverse drawing.Experiments were carried out and experimental results were analyzed systematically. Thickness distribution was obtained and analyzed of hydromechanical deep drawn cylindrical cup with flat bottom and hemispherical bottom. Typical defects in the process of two-step forming were analyzed and effective solutions were proposed.Areasonable process path was obtained, and the total drawing ratios are 3.3 was achieved for cylindrical cups with hemispherical bottom and flat bottom.