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Why does stainless steel slide rail rust?

Release time:

2021-06-19

Stainless steel slides are generally made of 304 stainless steel or 201 stainless steel. Stainless steel has the characteristics of corrosion resistance, oxidation resistance, easy processing, high hardness, and good ductility. It is widely used in all walks of life, but stainless steel will rust over time. This is not a quality problem, but caused by the use environment! So why does the stainless steel slide still rust? This is because stainless steel can resist part of acid, alkali and salt corrosion in dry air, and can prevent rust to the general humidity of the air. However, it is easy to rust in coastal cities where the air contains a lot of salt spray, because stainless steel is an extremely thin, strong, fine and stable chromium-rich oxide film (protective film) formed on its surface to prevent the continuous infiltration and oxidation of oxygen atoms and obtain the ability to resist rust. Once there is some reason, this film has been constantly destroyed, the oxygen atoms in the air or liquid will continue to penetrate or the iron atoms in the metal will continue to separate out, the formation of loose iron oxide, the metal surface will be constantly corroded. There are many forms of damage to this surface film. The following are common in daily life: 1. The surface of stainless steel contains dust containing other metal elements or attachments of heterogeneous metal particles. In humid air, the attachments The condensed water between the object and the stainless steel connects the two into a micro-battery, causing an electrochemical reaction, and the protective film is damaged, which is called electrochemical corrosion. 2. Stainless steel surface adhesion of organic juice (such as vegetables, noodles soup, phlegm, etc.), in the case of water and oxygen, constitute organic acid, long time organic acid on the metal surface corrosion. 3. Stainless steel surface adhesion contains acid, alkali, salt substances (such as the decoration of the wall of alkaline water, lime water splash), causing local corrosion. 4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), the condensed water forms sulfuric acid, nitric acid and acetic acid liquid points, causing chemical corrosion.

So why does the stainless steel slide still rust? This is because stainless steel can resist part of acid, alkali and salt corrosion in dry air, and can prevent rust to the general humidity of the air. However, it is easy to rust in coastal cities where the air contains a lot of salt spray, because stainless steel is an extremely thin, strong, fine and stable chromium-rich oxide film (protective film) formed on its surface to prevent the continuous infiltration and oxidation of oxygen atoms and obtain the ability to resist rust. Once there is some reason, this film has been constantly destroyed, the oxygen atoms in the air or liquid will continue to penetrate or the iron atoms in the metal will continue to separate out, the formation of loose iron oxide, the metal surface will be constantly corroded. There are many forms of damage to this surface film, and the following are common in daily life:

1. The surface of stainless steel contains dust containing other metal elements or the attachment of heterogeneous metal particles. In the humid air, the condensate between the attachment and the stainless steel connects the two into a micro battery, which leads to an electrochemical reaction, and the protective film is damaged, which is called electrochemical corrosion.

2. Stainless steel surface adhesion of organic juice (such as vegetables, noodles soup, phlegm, etc.), in the case of water and oxygen, constitute organic acid, long time organic acid on the metal surface corrosion.

3. Stainless steel surface adhesion contains acid, alkali, salt substances (such as the decoration of the wall of alkaline water, lime water splash), causing local corrosion.

4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), the condensed water forms sulfuric acid, nitric acid and acetic acid liquid points, causing chemical corrosion.