Why do stainless steels need to be chemically treated?

INOX combines chemical and electrochemical processes to make stainless steel more durable, better and more functional.

Welding and heating stainless steel forms an area on the surface of the steel that has a lower level of chromium. This causes heat tint, in which colors on the oxide layer vary from yellow to blue. Heat tint can often be found in heat affected areas of welded stainless steel fabrications, even if the process was gas shielded.

In this process, since it oxides more readily than iron, chromium is diffused to the surface of the steel. This leaves the layer below the surface of the steel with a lower level of chromium which makes it less corrosion resistant than the rest of the steel.

Visible heat tint of the surface of the steel makes the surface less corrosion resistant. By removing the heat tint and restoring the protective passive layer chemically, we are able to give stainless steel back its natural corrosion resistance.

In order to enhance the corrosion resistance of stainless steel even further, we can enrich the surface of the steel electrochemically with chromium. Elements which make up the alloy, are removed at different rates. Iron and nickel atoms are more easily extracted from the crystal lattice than chromium. Electropolishing removes mainly iron and nickel from steel, which leaves the surface of the steel rich in chromium. The abundant chromium allows the electropolished surface of the steel to passivate more efficiently than an untreated surface.

By electropolishing the steel, we are able to achieve a flawless and sleek surface. This electrochemical treatment is technically superior to mechanical polishing. In the process, the surface is not contaminated in any way and the treated surface is passive and has great corrosion resistance.

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INOX Finland

INOX Finland optimises the properties of stainless steel with chemical treatments. We specialise in bringing up the best in stainless steel. By selecting the right materials and optimising their qualities, we are able to produce the most outstanding results.