Method for cold deformation of an austenitic steel

A method for partial hardening of an austenitic steel by utilizing during cold deformation a Twinning Induced Plasticity (TWIP), Twinning Induced Plasticity/Transformation Induced Plasticity (TWIP/TRIP) or Transformation Induced Plasticity (TRIP) hardening effect,

• wherein cold deformation is carried out by cold rolling at least one surface of the steel to be deformed with a forming degree (Φ) of 25≤Φ≤60% in order to achieve in the steel at least two consecutive areas with different mechanical values in thickness, yield strength (Rp0.2), tensile strength (Rm), and elongation,
• each of the consecutive areas has a ratio (r) between an ultimate load ratio (ΔF), which is an ultimate load (F2) after deforming the area divided by an ultimate load (F1) prior to deforming the area multiplied by 100, and a thickness ratio (Δt), which is a thickness (t2) of the area after deforming the area divided by a thickness (t1) of the area prior to deforming the area multiplied by 100, such that the ratio r is ΔF/Δt and r is 1.0<r<2.0,
• and the areas are mechanically connected to each other by a transition area having a thickness that is variable from a thickness of a first area in the deformation direction to a thickness of a second area in the deformation direction.