Experimental Study and Simulation of Semi-Constrained Groove Pressing of Interstitial Free Steel Sheet

In this research, semi-constrained groove pressing (SCGP) as one of the severe plastic deformation techniques was investigated to achieve an ultrafine-grained structure in interstitial free steel sheets. The maximum of four semi-constrained groove pressing passes was successfully applied on the samples and the effects of the number of SCGP passes on the microstructure and mechanical properties of the samples were investigated. The microstructural investigations of the deformed specimens indicate that the semi-constrained groove pressing can effectively reduce the grain/crystallite size so that it ranges from about 41 μm in annealed condition to 232 nm after four passes. The results also showed that the strength and hardness of the samples are increased significantly by applying the pressing process. The highest tensile and yield strengths were observed in the two-pass SCGP processed sample, which showed an increase of about 90% and 75%, respectively, compared to the initial sample. The maximum hardness value of 165 Vickers was obtained for a three-pass SCGP processed sample, which is about 68% higher than the annealed sample. Regarding the hardness tests results, the uniformity of deformation increased with increasing the number of SCGP passes. Finite element method was used to simulate the semi-constrained groove pressing, and the strain distribution was obtained for the deformed samples. The finite element simulation results correlated fairly well with the analytical results.