Does stainless steel corrode? Corrosion
Stainless steel will corrode if the conditions are suitable severe, but they are significantly more corrosion resistant than basic carbon steels. To be called a stainless steel, a grade must contain >10.5% chromium. This creates a protective passive layer on the surface when the steel is exposed to oxygen, which protects the underlying metal from corrosion. If this layer is physically damaged and unable to regenerate then corrosion will occur. Inclusions from the steelmaking process may occur at the surface of a component, which means there will be a gap in the passive film where corrosion can initiate. Finally, the geometry of a component may give rise to particularly aggressive localised conditions, leading to crevice and then pitting corrosion. Ultimately, if the medium in contact with the stainless steel is sufficiently aggressive i.e. concentrated reducing acids, or the temperature is elevated, then corrosion will occur on almost any stainless steel.