Investigation of springback control and movement of welding seam of tailor-welded blanks in forming with blank holder force

By the methods of theoretical analysis, experiments and simulations, the movement of welding seam and the springback characteristic of tailor-welded blanks(TWBs)with longitudinal welding seam were investigated on the different blank holder force(BHF) for TWBs' springback control.In order to control movement of welding seam and even to control TWBs' springback, the formula about the control of movement of welding seam was deduced according to the principle that equal sectional stress is distributed on each side of TWBs.From the results about experiments and simulations, when BHF is small, TWBs' springback is in the midst of that of non-welded blanks, while with the increase of BHF, TWBs' springback is the biggest among them.The increase of total BHF brings double effects, on the one hand, TWBs' springback decreases with the increase of BHF, and on the other hand the movement of welding seam on TWBs increases with the increase of total BHF.In the condition of immovable total BHF, by adjusting the distribution of BHF, the movement of welding seam is eliminated and the springback reaches to the minimum.To sum up, on the thought of uniform deformation, a big enough total BHF is adopted, and a proper distribution of BHF applied to each side of TWBs in forming can reduce welding seam movement and get the minimum TWBs' springback, which gives new theories and methods to control TWBs' springback.