Why is a ferrite test necessary?
Ferrite testing is sometimes necessary to avoid material failure in duplex and austenitic stainless steels. A ferrite content that is too high or too low can be detrimental. If the ferrite content is too low, then the stainless steel may be susceptible to solidification cracking (hot cracking) upon welding.

How do you identify a ferrite?
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The Feritscope FMP30 measures according to the magnetic induction method. A magnetic field generated by a coil enters into interaction with the magnetic components of the specimen. The changes in the magnetic field induce a voltage proportional to the ferrite content in a second coil. This voltage is then evaluated.

What is ferrite number?
A Ferrite Number is a description of the ferrite content of a weld metal determined using a standardized procedure. ... The Ferrite Number of a weld metal has been considered approximately equivalent to the percentage ferrite content, particularly at low FN values.

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