Pitting corrosion is localized in a very limited region of the surface, the remainder of which is protected by a passive film.
In very severe occasions, the pit develops and can eventually lead to complete perforation of the metal. The correct selection of the grade of stainless steel is essential to avoid this phenomenon.
The type of medium most liable to promote pitting corrosion is seawater, but 'tap' waters can also be aggressive. The low roughness of the surface and the major content of alloying elements, chromium, molybdenum and nickel are parameters that affect the resistance to pitting corrosion. The pitting potential for a given medium can be used to rank different stainless steel grades in terms of their resistance to this type of attack.
If you have any doubt of the behaviour of stainless steel in different medium, do not hesitate to contact us through our channel 'ask our experts'. We will be happy to help!