Why are stainless steel doors rusty?

When there are brown rust spots (spots) on the surface of stainless-steel doors, people will feel very strange. You will think that "stainless steel doors should not rust, there must be a problem with the stainless steel material".

In fact, this is the lack of understanding of stainless-steel doors. Stainless steel doors will also rust under certain conditions.

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• Cause of rust

Stainless steel door has a thin, firm and stable chromium rich oxide film (protective film) formed on its surface to prevent the continuous infiltration and oxidation of oxygen atoms, so as to obtain the ability of anti-corrosion.

Once the film is continuously damaged for some reason, the oxygen atoms in the air or liquid will continuously penetrate, then the iron atoms in the metal will continuously separate out, forming loose iron oxide, and the metal surface will be continuously corroded. There are many forms of destruction of the surface film.

1. There are dust containing other metal elements or attachments of dissimilar metal particles on the surface of the stainless-steel door. In the humid air, the condensate between the attachments and the stainless-steel door connects them into a micro battery, which leads to electrochemical reaction and damage the protective film, which is called electrochemical corrosion.

2. The surface of stainless-steel door is adhered with organic juice (such as melons and vegetables, noodle soup, phlegm, etc.), which constitutes organic acid in the case of water and oxygen, which cause the corrosion.

3. The surface of stainless-steel door contains acid, alkali and salt substances (such as alkali water and lime water splashing on the decoration wall), will cause corrosion.

4. In polluted air (such as atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), sulfuric acid, nitric acid and acetic acid liquid points are formed in the presence of condensate, causing chemical corrosion of the SS doors.

• Precautions for use

The above conditions can cause the damage of the protective film on the surface of the stainless-steel door and lead to corrosion. Therefore, in order to ensure that the metal surface is permanently bright and not corroded, we suggest:

1. The surface of decorative stainless-steel door must be cleaned and scrubbed frequently to remove attachments and eliminate external factors causing decoration.

2. 316 stainless-steel doors shall be used in coastal areas, which can resist seawater corrosion.

3. The chemical composition of some stainless-steel doors in the market cannot meet the corresponding national standards and cannot meet the 304 material requirements, which will also cause rust, this requires users to carefully select the products of reputable steel door manufacturers.