Patent ID: 8181331
Filing Date: 2012-05-22
Classification: C21D,C25D,Y10T

Abstract:
1. A method for producing hardened structural parts from sheet steel, wherein the hardened structural parts have cathodic corrosion protection, comprising: shaping at least one shaped part made of sheet steel provided with a cathodic corrosion protection coating, wherein the cathodic corrosion protection coating is applied using a hot-dip galvanizing, wherein the coating is a mixture comprising zinc, and the mixture contains at least one element with affinity to oxygen in a total amount of 0.1 weight-% to 15 weight-% in relation to the entire coating, and wherein in the course of heating the sheet steel to the temperature required for hardening, a skin of an oxide of the at least one element with affinity to oxygen is formed on a surface of the sheet steel thus imparting cathodic corrosion protection; performing a final trim of the shaped part, punching, and/or the creation of a perforation pattern, prior to, during or after shaping of the shaped part; heating the shaped part, at least over partial areas, under the admission of atmospheric oxygen to a temperature which permits austenizing of the steel material subsequent to performing the final trim, punching, and/or the creation of a perforation pattern on the shaped part; and thereafter transferring the structural part to a mold-hardening tool and performing mold-hardening in the mold-hardening tool, wherein the structural part is cooled by the contact with and pressing by the mold-hardening tool and is hardened thereby; wherein the shaping and trimming, as well as punching and arrangement of a perforated pattern on the structural part, are performed in such a way that the shaped part is embodied to be 0.5% to 2.0% smaller than the finished structural part.