Our Metals

Stainless steels containing chromium and nickel equivalents between 10.5% and 30% are called ferritic, as they have a metallographic structure formed by ferrite. Higher nickel equivalents have a decreasing ferritic composition. Ferritic steels are magnetic (they are distinguished by their attraction to a magnet). With carbon percentages below 0.1%, these steels are not hardenable by heat treatment. However, steels with carbon content between 0.1% and 1% are hardenable (they have hard martensite, as lower carbon content is too low to harden). They are called "martensitic" stainless steels, because they have in their metallographic structure being magnetic, for highly alloyed stainless steels, the pure martensitic steel (without mixture with austenitic and ferritic) with Ni equivalent less than 18% (Cr equivalent 0%) to "13% Cr equivalent and 7% Ni equivalent", and up to 8% Cr equivalent and 0% Ni equivalent (this can be easily followed in the Schaeffler diagram of Cr-Ni equivalents).