Determining Springback Behavior of High-Strength Steels via Channel Forming Process

Abstract

The increasing use of high-strength steels in sheet metal automotive parts usually brings about the springback problems that can not be easily solved, compared to stamping the parts of conventional steel grades. Prediction and compensation of springback at the design stage is very important from both, the academic and the industrial perspectives. For this purpose, finite element analysis and simulative tests are used to understand formability properties of the material. In this study, springback behaviour of high-strength steels was investigated. Angular channel forming process is used as a simulative test with the DP600, DP1000, and DP1400 materials. Channel forming die tools were designed using a shallowly curved geometry for investigating springback behaviour of materials. Die tools were manufactured and forming process was performed at a hydraulic press machine. Sample surfaces were scanned using optical scanning. Then, experimental springback surfaces were compared with reference geometry by shape deviation analysis. It is observed that springback amount of DP1400 is much greater than those of DP600 and DP800 steels. The DP600 steel has minimum springback amount in the flange region and it has shown the smallest deviation from the reference forming surface, as a result of shape deviation analysis.