Although the demand of aluminum alloys has been increasing to reduce vehicle's weight in automotive industries, the low formability of aluminum alloys has made a limit on industrial applications. This work presents an infrared ray (IR) local heat treatment in the purpose of improving formability of aluminum alloys. The concept of the IR local heat treatment is focusing IR rays on target areas where the level of plastic deformation reaches the fracture level. The local heat treatment employs the intermediate heat treatment scheme that is conducted between two stages, 1～(st) forming and 2～(nd) forming. In the 1～(st) forming, the blank is deformed until a part of the blank reaches 15% strain. Then, the part is locally heat treated. After the heat treatment, the 2～(nd) forming makes the heat treated blank match the target shape. Authors recently conducted this heat treatment with an IR local heating method to resolve the formability problem of an AA5083 alloy [1]. However, in the paper, the IR heat treatment was applied to only a linear heating shape. Neither the heat treatment for a curved shape nor local heating effect in temperature distribution was discussed in the paper. In this work, the IR heat treatment is studied in three points of view. The first is to shortly introduce the IR heat treatment in the purpose of improving formability with the AA5083 alloy. The second is studying the local heating effects in temperature distribution and application of a curved shape. Finally, an industrial application of tailgate is discussed with reduction of heating energy. The results show that this focused IR heating can improve formability with reducing heating energy for industrial applications.
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