平坦化された5052アルミニウム合金薄板のインクリメンタル張出成形の可能性

抄録

For CO₂ emission reduction, a cold recycling process of sheet metal wastes has been proposed. In this process, a bent sheet of sheet metal waste is unbent into a sheet metal with a triangular residual corner, and this residual corner is incrementally flattened. The thinned bent corner can be thickened during the incremental flattening. However, this flattened sheet has a groove on the center of the thickened region, i.e., the thickness of the bent corner after flattening is thinner than the thickness of the surroundings. In the cold recycling, this groove should influence on the forming limit of the flattened sheet metal. Here, we focused on this groove and experimentally investigated the possibility of cold recycling of 5052 aluminum alloy sheets. Although the forming limit of the flattened 5052 aluminum alloy sheet was decreased in that of uniform 5052 alloy sheet, this flattened sheet can be formed into conical shells by incremental forming. Furthermore, it was found that the groove on the thickened region was shallow because of shortening the length of the triangular side of the residual corner, and then the forming limit of this flattened sheet was increased. These experimental results suggest that the forming limit of the flattened 5052 aluminum alloy sheet should be close to that of a uniform 5052 alloy sheet as the groove is shallower.