Ferrite Meter

To address the need to measure the amount of
ferrite in a sample the Welding Research Council
introduced the Ferrite Number (FN) as a
standardised value which related to the ferrite
content of an equivalently magnetic weld metal.
The volume percentage of ferrite can be estimated
as about 70% of the FN but the relationship
depends upon the type and origin of the stainless
steel used and the measurement technique.
The Diverse Ferrite meter MF300F+ measures the
Ferrite number (FN) of austenitic and duplex
stainless steel weld material. It has a probe that is
sensitive to ferrite content in a 10 mm area to a
depth of approximately 1 mm. The instrument is
calibrated using the secondary world standards
held at The Welding Institute. All 16 standards are
used in the calibration giving an instrument with a
measurement range from 0 to 115 FN. Transfer
standards are supplied with the instrument
allowing performance to be verified at any time.