This paper, which includes an experimental analysis and theoretical predictions, presents a method to investigate the formability of high strength steel sheet 22MnB5 at elevated temperatures. In this method, two designs for tensile test specimens with laser engraving grids are developed and used to obtain the strain paths of a uniaxial tensile state and the plane strain occurring at elevated temperatures using a Gleeble simulator. On the other hand, a modified Cockcroft criterion that takes strain path into consideration is employed to predict the entire forming limit diagram. A forming limit diagram could be established as a result of using the modified Cockcroft criterion together with the limit strains obtained from the tensile tests based on two novel specimen designs. In this paper, forming limit diagrams at three strain rates and forming limit diagrams at temperatures ranging from 650C to 850C were established.
Lee, R. S., Lin, Y. K., & Chien, T. W. (2014). Experimental and theoretical studies on formability of 22MnB5 at elevated temperatures by Gleeble simulator. In Procedia Engineering (Vol. 81, pp. 1682–1688). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2014.10.213