Advantageous selective surface oxidation of iron-chromium steel

摘要

Modern consumer products require high precision metallic parts so as to meet the quality demands of consumers. Therefore, in addition to corrosion resistance the surfaces of commercial products should have a nicely looking and appealing surface finish. To achieve these objectives several consecutive processing steps are performed on martensitic chromium steel, e.g. first forming the desired shape, followed by a heat treatment to attain the required mechanical strength. This latter step, the so-called hardening process, includes phase transformations in the bulk of the product. Consequently, a protective passive layer on the top surface is subjective to changes during the fabrication process.