Stainless steel will corrode if the conditions are suitable severe. However, like other corrosion resistant alloys, 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.
The geometry of a component may give rise to particularly aggressive localised conditions, leading to crevice corrosion 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.
Stainless steel is particularly ideal for exposed applications, marine environments and industrial applications where other metals would not survive, or where continued maintenance and replacement is not feasible.
In domestic applications or inland environments, stainless steel is unlikely to corrode if correctly specified and installed. In many of these applications, its appearance is as desirable as its long-term performance.
Having supplied corrosion resistant alloys to demanding applications for over 80 years, Langley Alloys Limited is the go-to for stainless steels. With locations in the UK, the U.S. and Singapore, we carry extensive stocks of advanced stainless steels in bar, plate and tube form. If you would like to find out more about our product range, please don’t hesitate to contact us, a member of our team will be happy to answer any questions that you may have.