Stainless steel 904L
904L is an austenitic stainless steel, characterized by high corrosion resistance in the most aggressive environments. It is also known as super-austenitic and it is the ultimate solution to corrosion problems, before considering nickel and cobalt based alloys. Resistance to christlyne corrosion is ensured by the low carbon content, and also the high presence of chrome and molybdenum gives it a good resistance even in chlorine environments. Nickel represents 24-26% and together with copper, provides good resistance to stress corrosion breakage and very good resistance in sulphuric environments. Thanks to all these features, it is highly used in paper mills, in desulphurization facilities and in the synthesis chemical industry for the production of phosphoric and sulphuric acid, and artificial fertilizers.
Rolex and Stainless steel 904L
Rolex has started using 904L steel for its cases in 1985, for the case of Submariner 168000. In 2006 Rolex has started producing its bracelets with this steel, instead of using the 316L. There are two discernible reasons:
- the first one is purely aesthetic, in fact this steel shines more that 316L;
- the second one is more on the physical, chemical and mechanical side; in fact this steel has higher resistance to corrosion and shocks than 316L.
On the other hand, 904L steel has forced Rolex to get more specific machines for its processing and it is much more expensive than 316L.