3. Ferritic stainless steels

3.1 Composition and properties

Ferritic steels contain from 10 to 30% chromium (table 5 ), with reduced carbon and nitrogen content (extremely low in the case of purely ferritic and high-alloy ferritic steels).

They can contain additions such as :

• molybdenum to improve their corrosion resistance;

• titanium or niobium to trap carbon and improve the properties of welded joints.

• Purely ferritic steels have no transformation point and are therefore very sensitive to grain coarsening above 800 ˚C. It is impossible to regenerate their structure by heat treatment....