The draft standard DIN 50938 "Burnishing of components made of ferrous materials - Requirements and test methods" specifies the requirements and test methods for burnishing coatings on components made of ferrous materials that have been produced by a chemical reaction in an immersion process. This document excludes black deposits produced at room temperature by means of acidic solutions containing heavy metals and other processes for the production of black oxidizing coatings.
Uniform black coatings
Burnishing is used to produce uniform black coatings on ferrous materials (cast iron, unalloyed and low-alloy steels) in order to give the workpieces a specific appearance while largely retaining their dimensional stability. This document is not applicable to mechanical fasteners and semi-finished products.
Deadline for comments ends in November
The draft was prepared by the working committee NA 062-01-76 AA "Chemical and electrochemical coatings" in the DIN Standards Committee for Materials Testing (NMP). The document can be obtained from Beuth Verlag GmbH, 10772 Berlin (address: Am DIN-Platz, Burggrafenstraße 6, 10787 Berlin), www.beuth.de. The draft can be commented on in the draft standard portal until November 6, 2024.