The effect of cyclic straining on the drawing stress of low carbon steel bars

The investigations covering the work hardening behavior of metals under strain path changes have pointed out the possibility of employing the strain softening phenomenon in sequential forming operations, specially in the case of cyclic straining. In this paper, the effects of cyclic torsion on the drawing stress of low carbon steel bars have been investigated. The material was drawn up to five passes. Cyclic straining was carried out between the last two stages of drawing and between every drawing pass. The substructural aspects of the bars were also analyzed. Cyclic torsion led to a decrease in the drawing stress values, whose magnitude depended on the number of forming passes considered in the experiment. The results also showed the occurrence of non-cumulative strain softening effects. Dislocation restructuring was found to be the softening mechanism related to the results.