The structure of stainless steel oxide scale

    The oxide scale on the surface of stainless steel has a dense structure and strong adhesion to the substrate. It must be cleaned before the subsequent passivation, electroplating, coloring and other decorative treatments.

     (1) The chemical composition of stainless steel oxide scale. Stainless steel contains chromium, nickel, iron, a small amount of carbon and silicon, and there may be elements such as manganese, titanium, molybdenum, tungsten, etc. In the process of smelting, casting, hot rolling, heat treatment, welding, etc., oxide scale will inevitably be formed , There are a variety of oxide structures in the oxide scale composition.

    (2) The complexity and harmfulness of stainless steel oxide scale. The complexity of the stainless steel oxide scale structure damages the integrity of the oxide scale. The imperfections include the unevenness of the crystal structure and electronic structure of the film. Incomplete oxide scale not only has no decorative appearance, but also accelerates the electrochemical corrosion of the metal surface. The formation of new oxide in the oxide film will generate stress on the metal surface due to the difference in volume. The thermal expansion coefficient of the oxide and the substrate is different, and corresponding stress will also be generated. The presence of surface stress accelerates the stress corrosion of the surface. Therefore, incomplete oxides and scales formed on the surface of stainless steel due to various reasons are harmful and useless. Removal of these oxide scales on the surface of stainless steel is of great practical significance for the smooth processing of the next process, preventing corrosion of the stainless steel surface, keeping the surface smooth, and prolonging the service life of stainless steel parts.

(Huiputech)