Processing of DP590 steel using single point incremental forming for automotive applications

The demand for incremental sheet forming is increasing specifically in the automotive sector for forming complex shapes with high accuracy. The present work investigates the incremental forming behavior using different parameters namely, fracture forming limits, limiting wall angle, thickness variation, and form accuracy. The formability of the material has been evaluated using the varying wall angle conical (VWACF) and pyramidal (VWAPF) frustums. The limiting wall angles for conical and pyramidal frustums are found to be 68.28 degrees +/- 1.36 degrees and 68.90 degrees +/- 1.37 degrees. The strain distribution revealed that the pyramid faces and corners have undergone the plane strain and biaxial deformation respectively. The fracture limits and strain paths are identified experimentally and validated numerically using Finite Element (FE) simulations. The experimental and simulated thickness distributions have been compared and found in good agreement as the average absolute error was found to be less than 8.5 +/- 0.02%. The error compensation method has been used for improving the accuracy of the formed components. The fracture in the specimens occurred without any hint of substantial necking. The electron backscatter diffraction (EBSD) study indicates the increase of local misorientations, and grain refinement, which has limited the formability of the material and ultimately led to the failure in the specimens.