Bending of third generation steel: Experimental and numerical approach

The development of a new class of material, such as third-generation advanced high-strength steel, requires a deep understanding of mechanical behaviour before its use in industry. One of the critical issues in sheet metal forming processes is dimensional accuracy, which is strongly dependent on the elastic recovery that can manifest itself as springback or spring forward [1]. This undesired defect results from the materials parameters and/or tools geometries [2]. One common way to evaluate the springback/forward is through bending tests. This work aims to investigate the existence of springback/forward on the selected material, its magnitude and dependence on the tool geometry and test the performance of the commercial finite element software Abaqus 2017 to predict the observed behaviour. The 3rd GEN steel, CR980XG3 (TM) produced by US Steel is subjected to V-bending to evaluate the existence of springback or spring-forward. Furthermore, to evaluate the dependence of springback/forward on the tool's geometry, the V-bending tools with different bending angles (namely, 60 degrees and 90 degrees) and different punch radii (namely, 5 degrees and 10 degrees) are used. The load is applied by a Shimadzu AG-X plus 100kN, and the deformation is measured by digital image correlation (DIC) using the GOM ARAMIS 3D 5M system. Numerical analysis of the bending tests is made using Abaqus 2017 software. The experimental results show that the material exhibits springback and spring forward depending on the tool geometry. The strain distribution through the thickness is correlated with the springback/forward.