This is an opportunity to illustrate the case for stainless steel as an eminently suitable material for street furniture and other external features.
Stainless steel is a strong, robust and durable metal that far exceeds life spans of several other materials. Stainless steel is not just one material, it is a family of chromium containing steels, which all possess an inherent resistance to corrosion. The chromium is distributed throughout the steel and its purpose is to form a sub-microscopic surface layer of hard, adherent chromium oxide on steel, a few atoms thick. The film is known as the passive layer, and it protects the underlying material from attack by corrosive species. If the layer is damaged in any way, it instantly reforms in the presence of oxygen to protect the surface of the material.
Unlike stainless steel, galvanised and painted steel does not possess such qualities. Although initially protected, paint can be damaged and chip off. It also degenerates and becomes porous. The galvanised (zinc) layer then corrodes, leaving the carbon steel exposed, thus leaving the steel susceptible to the accelerants of corrosion. Therefore stainless steel performs where iron and galvanised steel don’t. Such as environments where accelerants of corrosion occur include:
- Road salt and brine in coastal atmospheres
- Alkaline dog urine
- Weed killers/chemicals
- Other pollutants in the atmosphere
In addition, stainless steel is more resistant to vandalism, graffiti, and fire abuse. Should graffiti occur, the surface can be cleaned using paint thinners.