Operator‘s Manual FERITSCOPE
®
FMP30
Page 81
Measuring
7.2
Parameters That Influence the
-Ferrite Content Mea-
surement
The following factors influence the readings of a
-ferrite content measure-
ment:
Specimen curvature
The influence takes effect from following curvature diameters:
- diameters less than 50 mm (1.97 ") for convex curvatures,
- diameters less than 80 mm (3.15 ") for concave curvatures.
As a general rule: The measured
-ferrite content deviates increasingly
from the actual (true)
-ferrite content as the curvature diameter
decreases. Use the following equation for correction the measured
value:
Fe
T
= Fe
m
· k
Use the diagrams from page 83 and 84 to read the correction factor
for convex curved specimens, suitable for the used measurement unit.
Observe our limitation of liability on Page 6.
Specimen thickness
The influence takes effect from a specimen thickness less than 2 mm
(0.08 ").
As a general rule: The measured
-ferrite content deviates increasingly
from the actual (true)
-ferrite content as the specimen thickness
decreases.
Cladding thickness
The influence takes effect from a cladding thickness less than 2 mm
(0.08 ").
As a general rule: The measured
-ferrite content deviates increasingly
from the actual (true)
-ferrite content as the cladding thickness
decreases.
Edge distance of the measurement location
The influence takes effect if the distance of the measurement location
from the edge is less than 2 mm.
As a general rule: The measured
-ferrite content deviates increasingly
from the actual (true)
-ferrite content as the edge distance decreases.
Surface roughness
However, the surface roughness is strongly dependent on the
-ferrite
Fe
T
:
-
ferrite content within the trueness from the probe data sheet
Fe
m
: Measured
-
ferrite content
k : Correction factor readed from the diagram
