Last year we decided to take a ferry from Genova, on the Italian coast, over to Olbia in Sardinia, accompanied by my Range Rover Defender. Before bedding down for the night we took the opportunity to wander on deck. And there we found some examples of how to corrode stainless steel by applying the wrong surface finish. (Figs. 1 &2) The objects in question were lamp posts, which probably looked grand when first installed, with their highly polished surfaces, which we assumed had been produced by mechanical means.
My Italian colleagues and our companies have polished numerous items for marine applications and we have wrongly assumed that fabricators know that only electropoished stainless steel will best withstand aggressive marine atmospheres. Only by electrochemically removing a fine surface layer and producing a micro-smooth, highly reflective finish will stainless steel items give the performance required of them.
Fig. 3 shows a large framework after electropolishing. This forms the support for the rear diving deck on luxury boats. The framework, with all its numerous welds, is treated in its entirety to give the desired degree of corrosion protection.
A similar case can be made for swimming baths, where the chlorine laden atmosphere is extremely aggressive on stainless steel. Electropolished surfaces, with their superior passive layer, will best withstand attack by aggressive elements. Figs. 4 & 5 show electropolished handrails manufactured by Taunton Fabrications (www.tauntonfab.co.uk) and installed in swimming baths in Plymouth.
Anopol operates from two sites in the UK, one in Birmingham and the other in Bordon, Hampshire. The large frameworks were electropolished at the Birmingham works and the handrails by Anopol (South) in Bordon.