Stainless steel has demonstrated a reduced tendency to gall. The corrosion resistance of iron-chromium alloys was first recognized in 1821 by French metallurgist Pierre Berthier, who noted their resistance against attack by some acids and suggested their use in cutlery. Metallurgists of the 19th century were unable to produce the combination of low carbon and high chromium found in most modern stainless steels, and the high-chromium alloys they could produce were too brittle to be practical. In 1872, the Englishmen John T. Woods and John Clark patented a "Water Resistant" alloy in Britain, that would today be considered a stainless steel. In
Duplex stainless steel Duplex stainless steel Duplex stainless steels is the most recent family of stainless steels. They are called duplex (or austenitic-ferritic) grades because their metallurgical structure consists of two phases, austenite (face-centered cubic lattice) and ferrite (body centered cubic lattice) in roughly equal proportions. They are used for their good mechanical properties in the as-cast (and therefore as-welded condition) and/or their excellent corrosion resistance properties (particularly to stress corrosion cracking). They tend to be divided in three sub groups: Grade 1.4462 which has been the grade initially developed. and reperesents the "mid-range" of properties and is perhaps the most used today