Although stainless steel is named as such, it doesn't mean it's absolutely rustproof. The corrosion resistance of stainless steel is relative to ordinary carbon steel. Primarily, it forms a dense chromium oxide film on its surface to prevent oxygen atoms from continuing to penetrate, thereby achieving rust resistance.
Why can stainless steel rust?
Destruction of the oxide film:
Environmental factors: Harsh environments such as high temperature, high humidity, and strong acids and bases can destroy the oxide film, leading to rust.
Mechanical damage: Surface scratches, wear, and other damage can destroy the oxide film, exposing the internal metal and making it prone to rust.
Impurities: Impurities such as salt, acid, and alkali adhering to the stainless steel surface can form electrochemical corrosion in the presence of water.
Influence of alloy composition:
Insufficient chromium content: Chromium is the main element that forms the oxide film. If the chromium content is insufficient, the corrosion resistance will decrease.
Influence of other alloying elements: The content and proportion of different alloying elements will affect the corrosion resistance of stainless steel.
Influence of processing technology:
Excessive cold working deformation and improper heat treatment can affect the corrosion resistance of stainless steel.
How to prevent stainless steel from rusting?
Choose the right grade: Select a grade with better corrosion resistance based on the usage environment.
Keep the surface clean: Clean the stainless steel surface regularly to remove dirt and impurities.
Avoid contact with corrosive media: Avoid prolonged exposure of stainless steel to corrosive media such as acids, bases, and salts.
Pay attention to surface treatment: Passivation treatment can enhance the corrosion resistance of stainless steel.
In conclusion, the corrosion resistance of stainless steel is relative and it can rust under certain conditions. To extend the service life of stainless steel, it is necessary to comprehensively consider factors such as material selection, environmental factors, and surface treatment, and take appropriate protective measures.
Therefore, whether stainless steel will eventually rust depends on the specific usage environment and conditions.