Stainless steels, also known as Inox steels (from the French inoxydable) or stainless steel, are materials characterised by a higher resistance to corrosion, in certain environments, compared with common unalloyed steels (e.g. carbon steel).
This property is mainly due to the presence of very small amounts of carbon (≤ 0.07 %) and to the presence of chromium (minimum content ≥ 12 %), which, together with other alloying elements (e.g. nickel), readily reacts with the surrounding environment to form a thin protective oxide layer. This layer acts as a barrier, ensuring high corrosion resistance under specific conditions.
Depending on their microstructural constitution, stainless steels are divided into the following main families:
No. It would be a serious mistake to assume that stainless steels can always guarantee high corrosion resistance regardless of the environment and boundary conditions.
The corrosion resistance of stainless steel depends on many factors, including:
It should also be emphasised that corrosion phenomena affecting stainless steels often manifest in different forms compared to those observed in unalloyed steels, where corrosion typically produces clearly visible reddish products.
A careful observation shows that corrosion mechanisms in stainless steels can take very different forms. The most critical are generally localised corrosion phenomena, which may lead to the formation of cracks, pits and crevices.
During the design phase of a fall protection system, it is essential to correctly select products – and particularly the materials – according to the environmental conditions and boundary conditions in which they will operate.
It is equally crucial to monitor the condition of anchorage devices and fall protection systems through periodic inspections carried out by authorised competent personnel, in accordance with the intervals prescribed by the manufacturer.
Based on the inspection results and the progression of any detected corrosion phenomena, it may be necessary to replace affected components.
