When rust appeared on the surface of stainless steel cutlery, people were surprised: “Stainless steel does not rust, it is not stainless steel.” In fact, this is wrong view of the lack of understanding of stainless steel. Stainless steel cutlery will rust under certain conditions.
Stainless steel has the ability to resist atmospheric oxidation—that is, non-rust, and it also has the ability to corrode in acid, alkali, and salt-containing media—that is, corrosion resistance. However, its corrosion resistance varies with the chemical composition of the steel itself, the state of mutual addition, the use conditions and the type of environmental media.
Such as 430 steel pipe, in a dry and clean atmosphere, has absolutely excellent anti-corrosion ability, but when it is moved to the seaside area, it will quickly rust in the sea fog containing a lot of salt; while 304 steel pipe has performance good. Therefore, it is not any kind of stainless steel, which is corrosion-resistant and does not rust in any environment.
There are many forms of damage to the surface of stainless steel, and the following are more common in daily life:
Stainless steel relies on an extremely thin, strong, dense and stable chromium-rich oxide film formed on its surface to prevent oxygen atoms from continuing to penetrate and continue to oxidize, thereby obtaining the ability to resist corrosion. Once this film is continuously destroyed for some reason, oxygen atoms in the air or liquid will continuously infiltrate or iron atoms in the metal will continuously separate out, forming loose iron oxide, and the metal surface will be continuously rusted.
There are many forms of damage to this surface film, and the following are more common in daily life:
- The surface of stainless steel has accumulated dust containing other metal elements or attachments of foreign metal particles. In moist air, the condensation between the attachments and stainless steel connects the two into a micro battery, which initiates an electrochemical reaction and protects the membrane is damaged and is called electrochemical corrosion.
- The surface of stainless steel adheres to organic juice which forms organic acid in the presence of water and oxygen, and the organic acid will corrode the metal surface for a long time.
- The surface of stainless steel adheres to containing acids, alkalis, and salt substances such as alkaline water and lime water splashing on the decoration walls, causing local corrosion.
- In polluted air such as the atmosphere containing a large amount of sulfide, carbon oxide, and nitrogen oxide, it will form sulfuric acid, nitric acid, and acetic acid liquid.
The stainless steel cutlery used on the dining table is made of the aforementioned stainless steel raw materials, and the stainless steel cutlery used by people rarely encounters corrosive liquids. So pay attention to cleaning and storage, generally can be used for a long time.
Among the raw materials of stainless steel cutlery, 304 (18/10 stainless steel )is the best material, which is higher in quality than 430(18/0 stainless steel ). Stainless steel cutlery made of better raw materials will make people feel relieved and happy to use!