Search

A new technology of local electrically assisted necking and thickening forming of 5A02 aluminum alloy tube is developed, to enhance the quality of tube necking and thickening and increase the thickness of the tube wall in thickening area. Advantages of the electroplasticity of pulse current are utilized to guarantee the forming quality of tube necking and thickening. Process parameters such as thickness of the guide block, contact mode of the upper electrode, and the cooling method were studied. The results indicate that the thicker the guide block, the less prone to premature bending and instability in the forming process. The integral electrode is the most stable and the best heat dissipation effect, which avoids the tube from internal buckling. With the increase of the cooling capacity, the average wall thickness increases first and then decreases. According to these results, a process scheme is designed, with which successful experiments have been performed. And the microstructures of the necking and thickening areas were studied by optical microscope. Local electrically assisted necking and thickening technology shows great benefits in tube extrusion forming. [ABSTRACT FROM AUTHOR]