Ferrite Content Measurement (FT) is a non-destructive method used to determine the ferrite phase balance in weld metal, base materials, and weld cladding of austenitic stainless steels and duplex steels. This inspection enables the determination of ferrite levels expressed either in ferrite percentage (Fe%) or as a ferrite number (FN).
Ferrite content measurement is based on the magnetic properties of ferrite, which—unlike austenite—is a ferromagnetic phase. Using a ferritoscope, the ferrite content is determined by measuring the magnetic permeability of the tested asset. The results are expressed in %Fe or FN units, in accordance with ISO 8249 and ISO 17655 standards.
The FT method is used for assessing ferrite content in welds of austenitic and duplex steels, inspecting weld cladding, and verifying materials in the chemical, petrochemical, power, and food industries. Regular ferrite measurements are essential for monitoring welding processes and ensuring the quality and integrity of welded joints. Thanks to our portable measuring instruments, we can conduct the tests both in laboratory conditions and directly on-site.