Martensitic stainless steels are iron-chromium alloys that contain from 10% to 18% chromium and can be hardened by heat treatment to high strength levels. Type 410 stainless steel is the basic alloy in this groupe. The martensitic types are lowest in their ability to withstand corrosion.
Adding more carbon to the basic martensitic alloy increases its hardness. But, as carbon is increased, chromium content is also increased to as high as 18% to maintain no less than 10% free chromium in the alloy for corrosion resistance. Other modified martensitic alloys contain additional elements, such as sulphur or selenium.
Martensitic varieties find major applications in products that must resist atmospheric oxidation, mildly corrosive chemicals, and wet or dry corrosion environments found in steam and gas turbine parts, bearings, and cutlery. The martensitic types are also magnetic in all conditions.
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