Hardening of Workpieces Subjected to Various Types of Elastoplastic Deformation

All types of plastic deformation, such as tension-compression, bending, and torsion, are implemented during cold metal forming. Each type of deformation results in specific hardening patterns. Cyclic deformation causes hardening-softening processes and residual stresses (RSs). RSs form due to reversible dislocation movement. A new dislocation structure forms as a result of polygonization during subsequent low-temperature annealing-aging, and thus RSs contribute to hardening. Shear deformation, i.e., torsion, generates the greatest number of dislocations. Tensile-compressive deformation gives no hardening effect at all.