MARTENSITIC STAINLESS STEELS
Martensitic stainless steels, with their structures resembling ferritic steels, are similar to low-alloy high-strength steels or carbon steels. However, due to their additional carbon content, they can be hardened through heat treatment—much like carbon steels—resulting in increased strength. The primary alloying elements are: 12–15% chromium, 0.2–1.0% molybdenum, and 0.1–1.2% carbon. Except for a few specific grades, martensitic stainless steels generally do not contain nickel. As shown in the microstructure above, martensitic stainless steels are magnetic. With increasing carbon content, their hardenability and strength improve, while toughness and ductility decrease. Due to their high carbon levels and other alloying elements, they can be hardened up to 60 HRC through heat treatment.
After a heat treatment process known as tempering or stress relieving, martensitic stainless steels achieve their optimal corrosion resistance. Compared to ferritic and austenitic grades, the corrosion resistance of martensitic grades is slightly lower. They offer good machinability and formability. Depending on the type and amount of alloying elements, a small amount of retained austenite may remain in their microstructure. Martensitic steels are highly effective in applications where strength and resistance to mechanical wear are required alongside corrosion resistance. They are also used as tool steels, and their range of applications is quite broad.