Room Temperature

Martensitic and ferritic-martensitic steels are characterised by their high strength and the fact that the strength is strongly affected by heat treatment.

Martensitic steels are usually used in a hardened and tempered condition. In this condition the strength of the steels increases with the carbon content.

The ductility of martensitic steels is relatively low. Ferritic-martensitic steels have a high strength in the hardened and tempered condition in spite of their relatively low carbon contents, and good ductility. They also possess excellent hardenability: even thick sections can be fully hardened and these steels will thus retain their good mechanical properties even in applications where thick sections are used.

Elevated Temperatures

Martensitic and martensitic-austenitic steels in the hardened and tempered condition exhibit high strength at moderately elevated temperatures. However, the useful upper service temperature is limited by the risk of over-tempering and embrittlement.

The creep strength is low and this type of stainless steel is normally not used above 300 °C. However, certain martensitic grades are used at higher temperatures. The wide range of elevated temperature strength is due to the wide range of strength levels offered by different grades and heat treatments.