Experimental and Numerical Investigation of Springback Behavior in Cold Forming of 1470 MPa Martensitic Steel: Effects of Geometric Parameters and Press Force

Springback is one of the major manufacturing challenges affecting dimensional accuracy in the cold forming of ultra-high-strength martensitic steels used in automotive applications. In this study, the springback behavior of 1470 MPa martensitic steel was investigated through a combined numerical and experimental approach. Forming and springback simulations were carried out using AutoForm software following the development of process and tooling designs. Based on the simulation results, prototype dies were manufactured and experimental parts were produced under press loads of 540 T and 740 T. The formed components were digitized using an ATOS optical scanning system, and the acquired three-dimensional geometries were evaluated in GOM Inspect software and compared with the numerical predictions. In addition, the influence of bending radius and chamfer angle on springback behavior was systematically analyzed through parametric studies. The results showed that reducing the bending radius from 5 mm to 3 mm decreased the maximum geometric deviation by approximately 16.2%, whereas increasing the radius to 7 mm resulted in an increase of about 22.2%. Similarly, decreasing the chamfer angle to 145° reduced the maximum deviation by approximately 9.9%, while increasing it to 155° led to an increase of about 10.4%. Better agreement between numerical predictions and experimental measurements was observed at a press load of 740 T. The findings demonstrate that geometric design parameters play a critical role in controlling springback behavior and that simulation-assisted geometric optimization can be effectively utilized to improve dimensional accuracy and reduce die development effort in the cold forming of ultra-high-strength steels.