Patent ID: 8778101

Claim:
A method of production of a steel sheet pressed part with locally modified properties, comprising the steps of: heating a steel sheet blank in a heating device in a first production step to the austenitic temperature of the material from which the blank is made; thereafter converting the steel sheet blank in a tool for deep drawing by deformation into a final drawn part; thereafter initially cooling the final drawn part inside the tool for deep drawing such that various locations of the final drawn part are cooled to various temperatures and/or at various rates during the cooling step, wherein a part of the final drawn part undergoes incomplete transformation of austenite into martensite, such that the final drawn part comprises retained austenite; thereafter placing the final drawn part in an annealing device and annealing the final drawn part under conditions whereby retained austenite stabilization takes place by diffusion-based carbon partitioning within the material from which the final drawn part is made; and removing the final drawn part from the annealing device and then cooling down in a final cooling step in air to ambient temperature.