Martensitic stainless steel
Stainless steels may be classified by their crystalline structure into three main types: austenitic, ferritic and martensitic. Martensitic stainless steels can be high- or low-carbon steels built around the Type 410 composition of iron, 12% chromium, and up to 1.2% carbon. They are usually tempered and hardened. Tempered martensite gives steel good hardness and high toughness; used largely for medical tools (scalpels, razors and internal clamps). Untempered martensite is low in toughness and therefore brittle.
The characteristic body-centered tetragonal martensite microstructure was first observed by German microscopist Adolf Martens around 1890. In 1912, Elwood Haynes applied for a U.S. patent on a martensitic stainless steel alloy. This patent was not granted until 1919.
Also in 1912, Harry Brearley of the Brown-Firth research laboratory in Sheffield, England, while seeking a corrosion-resistant alloy for gun barrels, discovered and subsequently industrialized a martensitic stainless steel alloy. The discovery was announced two years later in a January 1915 newspaper article in The New York Times. Brearly applied for a U.S. patent during 1915. This was later marketed under the "Staybrite" brand by Firth Vickers in England and was used for the new entrance canopy for the Savoy Hotel in 1929 in London.
- "Böhler N690 – Stainless Steel" (PDF). bohler-edelstahl.com. Böhler Edelstahl. Retrieved 2015-11-28.
- http://metals.about.com/od/properties/a/Steel-Types-And-Properties.htm, http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=199.
- Akhavan Tabatabae, Behnam; et al. (2009). "Influence of Retained Austenite on the Mechanical Properties of Low Carbon Martensitic Stainless Steel Castings". ISIJ International. 51 (3): 471–475. doi:10.2355/isijinternational.51.471.
- Rodney Carlisle; Scientific American (2005-01-28). Scientific American Inventions and Discoveries: All the Milestones in Ingenuity – From the Discovery of Fire to the Invention of the Microwave Oven. John Wiley & Sons. p. 380. ISBN 978-0-471-66024-8.
- "A non-rusting steel". New York Times. 31 January 1915.
- Sheffield Steel, ISBN 0-7509-2856-5.