Martensitic steels have the highest strength but also the lowest corrosion resistance of the stainless steels.

Microstructure image of a
martensitic stainless steel

Martensitic steels with high carbon contents are used for tool steels.

Due to their high strength in combination with some corrosion resistance, martensitic steels are suitable for applications where the material is subjected to both corrosion and wear. An example is in hydroelectric turbines.