What is the principle of stainless steel does not rust

- May 29, 2018-

 Stainless steel refers to steel that is resistant to weak corrosive media such as air, steam, water, and chemically etched media such as acids, alkalis, and salts. It is made from iron-chromium alloys and then incorporated into other trace elements. Due to its good metal properties and corrosion resistance compared to other metals, the finished vessel is beautiful and durable.

  Whether stainless steel is rusted or not, the content of chromium is the key. China's stipulated minimum chromium content in stainless steel can not be less than 12%. Because stainless steel contains a relatively high proportion of chromium, its surface is always in a passivated state under normal conditions (neutral and alkaline). This means that a protective film with a tight structure protects it from rust.

If the chromium content is low, that is, poor quality stainless steel, the surface can not produce a sufficiently close passivation film, can not play a protective role, this stainless steel still rust. In another case, stainless steel encounters highly active substances (such as salt in daily life, etc.), and contains relatively high levels of chlorine or fluoride ions. Even if the stainless steel contains high-quality stainless steel, the surface of the passive film will be destroyed. The surface of the stainless steel is in an active state. At this time, the stainless steel not only rusts but also dissolves heavy metal ions harmful to the body.