w
w
w
.d
iv
e
rs
e
-t
e
c
h
n
o
lo
g
ie
s
.n
e
t
Page 13
Magnetic Particle Inspection
A wide range of magnetising systems are used for Magnetic
Particle Inspection. The value of the magnetic flux density
required is specified in BS4069 as 0.72 Tesla. This is produced
when the magnetising coils generate a magnetic field of
2.4kA/m which is applied to a component made from material
with a relative permeability of 240.
The has a facility to provide simple pass/fail test for
the status of the applied field. To put the unit in this mode,
press tick to get to the menu, select MTB (Magnetic Test
Bench), you will then be prompted to switch test bench on or
off. If you select on, then press tick and you will be presented
with the value of the required threshold field, nominally 2400
A/m. Pressing the up arrow advances the threshold by 10A/m,
press and hold the up arrow for 2 seconds and the threshold
will advance by 100 A/m. Use up/down arrow to set the value
you require, then press tick to accept.
You will then be taken to the normal screen which will identify
the field size in RMS mode and an indicator to say whether the
field level is below the threshold (“Lo”) or above (“Ok”). To
check the magnetising system, switched it on and in the
absence of the component to be measured, the field should be
measured. If the value is greater than 2.4kA/m then the
magnetic field meets BS4069.
Operation - MPI
