Martensitic stainless steel

Martensitic stainless steel is a specific type of stainless steel alloy.

Stainless steels may be classified by their crystalline structure into three main types: Austenitic, Ferritic and Martensitic. Martensitic steels are low carbon steels built around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. They may be tempered and hardened. Martensite gives steel great hardness, but it also reduces its toughness and makes it brittle, so few steels are fully hardened.

The characteristic orthorhombic 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.^[1]

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.^[2] 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.^[3]

References

1. ^ Scientific American Inventions and Discoveries, p. 380, Rodney P. Carlisle, John Wiley and Sons, 2004, ISBN 0471244104, ISBN 9780471244103
2. ^ "A non-rusting steel". New York Times. 31 January 1915. 
3. ^ Sheffield Steel, ISBN 0-7509-2856-5