Capillary shaping is an upward pulling solidification technique for obtaining aluminum alloy hollow products with high structural stiffness and high mechanical properties. Recently, hollow frames with inner ribs and bent geometry are increasingly desired for optimizing car body stiffness and design of lightweight car body structures. Capillary shaping is an attractive process for manufacturing these components. However, it is necessary to control thermal conditions during the pulling process for fabricating bent products with high thickness accuracy, since thermal conditions influence the thickness of products and vary at the bent section due to differences in the pulling rates at inner and outer positions. In this study, the thermally stable conditions during the capillary shaping of aluminum alloy bent tubes were investigated. It is found that bent tubes with high thickness accuracy can be fabricated without any automatic controls of cooling conditions when thermally stable conditions are maintained.
