Backward Extrusion — Residual Deformability of Resulphurized Mid-Hard Steels

Abstract

Summary The backward extrusion and residual deformability after extrusion of resulphurized mid-hard steels (XC42 and 30CD4) have been studied. The residual deformability was examined in short tube compression, ring expansion and axial tension tests. In order to estimate the effect of anisotropy created by predeformation, the Cockcroft's ductile fracture criterion has been generalized to the anisotropic material. The experimental results have indicated that the spheroidizations of perlite and of the sulphide Inclusion offer a favourable effect. Backward extrusion predeformation, morphology of inclusions and anisotropy reduce more rapidly the transverse residual deformability than the axial residual deformability.