Influence of superimposed hydrostatic pressure on bending fracture and formability of a low carbon steel containing globublar sulfides

Bend tests under superimposed hydrostatic pressure were carried out on a low carbon steel containing globular sulfide inclusions to investigate the variation of ductile fracture and forming limits due to supression of void growth. Results show that increasing pressure enhances formability, as expressed by increasing intercept and decreasing slope of the forming limit line, due to a pressure-induced transition in fracture mechanism. A continuum mechanical model based on the growth and coalescence of voids under applied pressure is proposed that explains the experimental results and predicts the fracture limit under actual metalforming conditions. © 1990 by ASME.