Improvement of Limiting Drawing Ratio of a SPCC steel Using Sequential Action Forming with Inclined Blank Holder

This study aims to enhance the limiting drawing ratio (LDR) of cold-rolled carbon steel SPCC (JIS G3141) to 3.0 by applying a novel technique known as sequential-action forming (SAF) with an inclined blank holder. The SAF technique reduces material flow intensity during deep drawing, which delays cup wall stretching and breakage due to thickness adjustment. Additionally, SAF facilitates a significant increase in the LDR by controlling cup heights during the initial and subsequent deep drawing stages. An inclined blank holder, set at an angle of one degree, notably minimizes wrinkles on the flange of the drawn cup, offering a distinct advantage over other deep-drawing methods, such as multistep deep drawing and temperature-assisted forming. Before conducting experiments, a precise finite-element simulation was performed to evaluate the process parameters. Deep drawing tests on SPCC were conducted using FE simulations with the Yoshida 6th yield function to ensure the accuracy of the results.