When there are brown rust spots (spots) on the surface of stainless steel, people are surprised and think that "stainless steel is not rusty, rust is not stainless steel, maybe there is a problem with steel quality". In fact, this is a one-sided wrong view of the lack of understanding of stainless steel. Stainless steel will rust under certain conditions.

Stainless steel has the ability to resist atmospheric oxidation, that is, it is not rusty, but also has the ability to corrode in the medium containing acid, alkali and salt, that is, corrosion resistance. However, the corrosion resistance of the steel varies with its chemical composition, processing state, service conditions and environmental media type. For example, 304 stainless steel has excellent corrosion resistance in dry and clean atmosphere, but if it is moved to the coastal area, it will rust quickly in the sea fog containing a lot of salt, while 316 stainless steel performs well. Therefore, not any kind of stainless steel, in any environment can be resistant to corrosion, rust.

Stainless steel is formed on its surface by a very thin and strong, stable chromium rich oxide film (protective film), to prevent oxygen atoms from continuing to penetrate, continue to oxidize, and obtain the ability to resist corrosion. Once there is some reason, the film is constantly damaged, oxygen atoms in air or liquid will continue to penetrate or metal iron atoms will continue to separate out, forming loose iron oxide, the metal surface will be constantly corroded. The surface film is destroyed in many ways.

The following are common in daily life:

There are dust containing other metal elements or attachments of different metal particles on the surface of stainless steel. In humid air, the condensation water between the attachment and stainless steel connects them to form a micro battery, which causes electrochemical reaction and damages the protective film, which is called electrochemical corrosion. For example, just after the decoration of the new house, there are metal debris in the water pipe, which is easy to cause floating rust on the surface of the sink.

In the presence of water and oxygen, the adhesive SAP on the surface of stainless steel (such as melon and vegetable, noodle soup, phlegm, etc.) will form acid, which will corrode the metal surface for a long time.

The adhesion of stainless steel surface contains acid, alkali and salt substances (such as alkali water and lime water splashing on the decoration wall), causing local corrosion. More typical is decoration, workers use the sink, did not clean the sink in time, resulting in acid and alkali corrosion surface.

In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), sulfuric acid, nitric acid and acetic acid liquid points will be formed in case of condensate water, causing chemical corrosion.

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

1. The stainless steel surface must be cleaned and scrubbed frequently to remove the attachments and eliminate the external factors causing corrosion.

2. The chemical composition of some stainless steel in the market can not meet the corresponding national standards, so it will cause rust, which requires users to carefully select products from reputable manufacturers.

Article source: Guangzhou outdoor furniture project customizedhttp://www.gzpeimei.com