Ferrite content is a measure of the amount of ferrite in a steel. Ferrite is one form of microstructure - the internal crystal structure - that can exist within steel. The crystal structure helps to define the physical and mechanical properties of an alloy

A ferritic microstructure in a stainless steel is usually associated with high strength and resistance to chloride stress corrosion cracking. It is also magnetic in nature, which can be used to measure the ferrite content in

duplex and super duplex stainless steels by using a 'Ferrite scope'. This is a useful technique as it can be used 'in-situ', to assess the quality of welds or reviewing incoming stock without the need for test samples to be cut from the components.