差厚激光拼焊板的拉延切边回弹特性

Investigation of Draw-trimming Springback of Laser Tailor-welded Blanks

采用数值模拟和试验的方法,对厚度组合为1.2mm/0.8 mm的激光拼焊板进行拉延切边工艺分析,重点就压边力大小、摩擦因数、凹模圆角等参数对回弹的影响进行研究,测量各工艺参数下拼焊板拉延切边的凸凹模圆角处的回弹角、总的回弹角和侧壁曲率,还测量出拼焊板成形中的焊缝移动和应力分布情况和分析相互联系,并与拼焊板拉延弯曲回弹进行比较。分析认为,与拉延弯曲回弹相似,压边力、摩擦因数、凹模圆角等工艺参数对拼焊板拉延切边回弹有着明显的影响,而压边力是关键因素;拼焊板拉延切边回弹和拉弯回弹都与焊缝移动有密切的关系,控制焊缝移动将有利于回弹的降低;相比之下,拼焊板拉延切边回弹比拉弯回弹要小。

By the numerical simulation and experiments, the process analysis of draw-bending and draw-trimming of the tailor-welded blanks （TWBs） with the thickness ratio1.2 mm/0.8 mm are made, in which the effect of the blank holder force （BHF）, friction factor and die profile radius, etc. on the springback are mainly investigated. The TWBs＇ springback angle in the comer of ptmch and die, the total springback angle and the sidewall curvature are surveyed in draw-bending and draw-trimming. And the welded line movement, the stress distribution in TWBs forming and their interact relationship are analyzed. The TWBs＇ springback in draw-bending and draw-trimming are badly influenced by the BHF, friction factor, die profile radius etc., in which the BHF is the key factor; there is an intimate relationship between TWBs＇ draw-bending springback / draw-trimming springback and welded-line movement, by which it will be advantageous to reduce the TWBs＇ springback through controlling the welded-line movement. In comparison, the TWBs＇ draw-trimming springback is smaller than the TWBs＇ draw-bending springback, so it is better to use draw-trimming process for controlling TWBs＇ springback and improving the shape precision of TWBs＇ forming.