T.O. 33B-1-1
c.
Dead weight check for portable induced field equipment. AC electromagnet yokes shall have a lifting
power of at least 10 pounds, with a spacing of three to six inches between the legs. DC electromag-
netic or permanent magnet yokes shall have a lifting power of at least 30 pounds with a two to four
inch spread or 40 pounds with a four to six inch spread of the legs. Test weights should be locally
manufactured from 4 inches x 1-1/4 inches SAE 4130 or SAE 4340 bar stock. A 7-inch long piece of
this material will weigh approximately 10 pounds. Testing frequency shall be established as per
Table 1-3.
d.
Field indicator check. Perform check on in-use indicator daily or before use if used less frequently.
e.
Lighting requirements.
(1)
Blacklights.
(a)
Check the intensity prior to use.
(b)
Check new black light bulb intensity prior to its being placed into service.
(c)
Check black light and filter’s physical condition. Black light and filters SHALL be kept clean,
free of cracks or chips, and SHALL fit properly.
(2)
Check the ambient white light background in the f luorescent magnetic particle inspection booth.
It shall not exceed 2 foot candles at the inspection surface.
1.6.8
Process Requirements.
1.6.8.1
Pre Cleaning.
Prior to magnetic particle inspection examine the parts for the following:
a.
Removal of oils, grease, moisture, dirt, rust, scale and loose paint.
b.
Verify cleaning residues have been removed.
c.
Insure parts are adequately dried, especially in recessed areas.
d.
Verify all areas requiring masking and/or plugs have been covered.
1.6.8.2
Inspection Operations.
Observe the magnetic particle inspection operations being applied to assure:
a.
The applicable technical data is available.
b.
The appropriate magnetizing current is used (AC, DC, rectified AC).
c.
The appropriate magnetic particles are used (wet, dry, visible, f luorescent).
d.
The proper application of inspection media (continuous, residual).
e.
The required field directions are induced.
f.
The sequence of induced fields (circular versus longitudinal). Whenever practical the circular field
should be induced first. This is to facilitate the demagnetization process.
g.
The required magnetizing amperage is used and the part is checked for proper magnetization.
h.
The black light is allowed to warm up for a minimum of ten minutes, or until the required intensity
(1000 mwatts/cm2) is achieved.
i.
The required demagnetization procedure is used (30 point stepdown, AC coil).
j.
The adequacy of the field indicating device to determine adequacy of demagnetization.
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