AMST 212G Lecture Notes - Lecture 19: Shape-Memory Alloy, Pitting Corrosion, Ferrite (Iron)
20 Aug 2015
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Document Summary
A short description of the various grades of stainless steel and how they fit into distinct metallurgical families. It has been written primarily from a european perspective and may not fully reflect the practice in other regions. Stainless steel is the term used to describe an extremely versatile family of engineering materials, which are selected primarily for their corrosion and heat resistant properties. All stainless steels contain principally iron and a minimum of 10. 5% chromium. At this level, chromium reacts with oxygen and moisture in the environment to form a protective, adherent and coherent, oxide film that envelops the entire surface of the material. This oxide film (known as the passive or boundary layer) is very thin (2-3 namometres). The passive layer on stainless steels exhibits a truly remarkable property: when damaged (e. g. abraded), it self-repairs as chromium in the steel reacts rapidly with oxygen and moisture in the environment to reform the oxide layer.
