2A12铝合金大曲率半径钣金件热变形-淬火复合成形回弹规律

Springback law of 2A12 aluminum alloy sheet metal part with a large curvature radius in hot forming-quenching integrated process

航空航天领域存在一批种类多、批量小的大曲率半径铝合金钣金件,其常温成形时回弹大、成形精度差。为此,提出通过热变形-淬火复合成形来实现大曲率半径钣金件的回弹控制。首先,以大曲率半径带状构件为研究对象,揭示热变形-淬火复合成形回弹规律,并结合仿真进行回弹机制分析;然后,采用仿真得到的最佳工艺参数,进行复杂口框件成形。结果表明:较高温度利于抑制回弹,当温度达到490℃时,试件完全贴模;而常温成形时,试件几乎恢复平板形状。高温下切向应力显著降低,弹性变形较小,且模内淬火大幅限制了热畸变,进一步抑制了回弹。抑制2A12铝合金大曲率半径钣金件热变形-淬火复合成形回弹的最优成形温度为490℃,在该温度下成功地成形了高精度口框件,证实了热变形-淬火复合成形可用于大曲率半径铝合金钣金件的精密成形。

In the field of aerospace,there are a large number of large curvature radius aluminum alloy sheet metal parts with many kinds and small batches.When forming at room temperature,the springback is large and the forming accuracy is poor.Therefore,the springback control of sheet metal part with a large curvature radius was achieved by hot forming-quenching integrated process.Firstly,for banded part with a large curvature radius,the springback law in the hot forming-quenching integrated process was revealed,and the springback mechanism was analyzed by the simulation.Then,the forming of a complex buccal frame part was carried out by the optimal process parameters obtained by simulation.The results show that higher temperature is beneficial to inhibit springback.When the temperature reaches 490℃,the specimen is completely attached to the die,while formed at room temperature,the specimen almost returns to the shape of a flat plate.A higher temperature can cause the significant reduction of tangential stress,and the elastic deformation is small.In addition,in-die quenching greatly limits thermal distortion and further inhibits springback.The optimal forming temperature for hot forming-quenching integrated process springback inhibition of 2A12 aluminum alloy sheet metal part with a large curvature radius is 490℃.At this temperature,the high-precision buccal frame part is formed successfully,which proves that the hot forming-quenching integrated process can be used for precision forming of aluminum alloy sheet metal part with a large curvature radius.