Phenomenon of the Softening Cold-Deformed Low-Carbon Steel During Alternating Bending

For cold-rolled low-carbon steel, detected softening during alternating bending is accompanied by an increase in ductility and ability to strain hardening. The softening process is accompanied by a change at morphology of ferrite grains. Elongated grains after cold rolling acquire a shape close to a polyhedron after alternating bending. Compared to the strength properties, for which a maximum decrease corresponds to four bending cycles, the ductility and strain hardening ability of the metal continue to increase even after eight cycles. The non-monotonic nature of change in dislocation density depending on the number of bending cycles indicates complex substructural changes in cold-rolled metal, which has a dislocation cellular structure varying degrees of the perfection.