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Magnetic Flux Indicators Strips Type G - Instructions for Use
These foil type indicators are designed for use in both critical
and general engineering applications.
The foil
type magnetic flux indicators are used to give a clear guide as
to the direction of a magnetic field and can be used to give an
estimate of the field strength H across surfaces magnetized for
the application of Magnetic Particle inspection under the
control of various standards including B.B 6072
Interpretation
If one indicator shows indications clearly and the other none at
all, the direction of the induced magnetic field is at right
angles to the indicator which shows indications. If both
indicators show indications, the direction of the induced
magnetic field lies somewhere between the directions of the two
indicators; it is usually possible to deduce the direction by
the diffuse nature of the indications at the ends of the
indicators, in such a case the indicators should be re sited in
the direction which will lead to one showing indications and the
other not and the magnetization and application of magnetic
particles repeated. If neither indicator shows any indications
there are several possibilities the most common of which are: a)
that there is insufficient magnetic field induced in the
material for magnetic inspection to proceed and b) that there is
no external field as may occur in circular magnetization.
Interpretation of field strength can only be made when
Alternating current is used. the indicators must be mounted on a
vertical surface so that magnetic ink may drain off them readily
then it can be estimated that when one indication are clearly
visible the induced field in air above the surfaces of the work
pieces is greater than 2000 Amp/meter. When the
indicators are mounted horizontally NO ASSESSMENT of the field
strength can be made.
Instructions for use
Flux indicators which respond to the tangential component of the
field H in air above the surfaces of magnetized work pieces give
excellent evidence of the directions of the field. The
indicators can only be used to give an estimate of the strength
of the field when the work piece is magnetized by the current
flow technique, this is because when other methods of
magnetization are used e.g. a coil, a magnetic field is created
in the air whether there is a ferromagnetic item present or not
and the indicator will respond to such a field. This being so no
semi-quantitative estimate of the field strength can be made.
Estimates
of field strength can only be made when alternating current is
used for magnetization.
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Attach
one indicator to the work piece so that its long axis is in
the same direction as that of any expected defects.
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Attach
a second indicator at right angles to the first.
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Magnetize the work piece in the normal way and apply
magnetic particles.
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A
minimum of 3 seconds magnetization is needed to allow for
particle migration before the indicators are inspected with
the magnetizing current on.
For any
questions or queries regarding this product please
contact
us!
Technical Support
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Magnetic Flux Indicators Strips
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