Research On The Springback Of Bending In LY12 Aluminum Alloy Sheet

The perspective of aluminium alloys sheets used for the structural in automobile is very extensive instead of the steels. But it is hard for aluminium alloys to form because of the springback, which induces the workpiece fail to meet the requirement. At present time, there is few of study on the bending forming for aluminium alloys and the aluminium alloys sheets knowledgement about bending forming is lack, which interferes with the application of aluminium alloys sheets. So, it is very important and meaningful to investigate the bendingability for aluminium alloys sheets. In this paper, it mainly studies the springback of LY12 aluminium alloy sheets by V-bending and U-bending.For the V-bending, the springback value decreases with increasing of bending angle, which is influenced by the bending angle obviously on the thick sheet than that of on the thin sheet. When the radius is 2mm, the springback value for the thin sheet decreases from 1.22o with the bending angle of 60o to -0.6o with that of 120o during the wide sheet bending procedure and decreases from -0.17o to -1.43o for the thick sheet. The influence of open distance for die on the springback value is similar with that of the bending angle. When the radius is 4mm, the springback value for the thin sheet decreases from 3.47o with the open distance of 36mm to 1.22o with that of 44mm during the wide sheet bending procedure and decreases from 0.82o to -0.23o for the thick sheet. The effect of relative bending radius on the springback value is large. And the springback value increases linearly with increasing of relative bending radius. When the bending angle is 90o, the springback value for the thin sheet increases from -0.76o with the relative bending radius of 0.5mm to 6.27o with that of 8mm during the wide sheet bending procedure and increases from -1.53o to 2.26o for the thick sheet.For the U-bending, the springback value increases with increasing of bending clearance, which is influenced by the bending clearance clearly on the thin sheet than that of on the thick sheet. When the radius of die shoulder is 8mm, the springback value for the thin sheet increases from 15.48o with the bending clearance of 0.05mm to 19.15o with that of 0.3mm and increases from 5.42o to 13.15o for the thick sheet. The springback value is sensitive to the bending clearance, especially for the thick sheet. When the radius of die shoulder is 4mm, the increasement of springback value for the thin sheet is 2.87o when the the bending clearance increases from 0.05mm to 0.3mm, while it is 7.63o for the thick sheet. The effect of die shoulder radius on the springback value is complicated. When the bending clearance is 0.3mm, the springback value decreases from 18.47o for the die shoulder radius of 0mm to 17.93o for that of 4mm and then increases to 19.15o for that of 8mm for the thin sheet. While it is almost not changing for the thick sheet.