Analysis of forming characteristics for dual phase steel under warm incremental forming process

The demand for rapid prototyping techniques has been increasing in the field of automotive for the manufacturing of various parts with dissimilar shapes. In the present work, experimental and numerical investigations have been performed on an automotive-grade DP steel using an incremental sheet forming process at Room Temperature (RT) and 400 degrees C. Various formability parameters such as fracture forming limits, limiting wall angle, forming forces, thickness distribution, and geometrical accuracy have been analysed. The fracture limits of the material are evaluated by forming varying wall angled conical (VWACF), and pyramidal (VWAPF) frustums. The fracture limits of the material formed at 400 degrees C have been found to be 14.06% higher compared to room temperature fracture limits. The limiting wall angles for VWACF and VWAPF are found to be 70.73 degrees +/- 1.41 degrees and 67.97 degrees +/- 1.35 degrees, which are also higher than the formed constant wall angled frustum. The forming forces measured from experimental and FE simulations are in good agreement with the predicted forming forces from Arene's equation. The minimum thickness obtained from experimental and FE simulations are in good agreement with each other with an absolute error of less than 4.5% and 7% for VWACF and VWAPF.