EDGE 2500535 - Caterpillar

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The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
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Before using developer make sure that, it is mixed thoroughly by shaking can. Holding can approximately 8-12 inches away from part, apply an even, thin layer of developer over the area being inspected. A few thin layers are a better application method than one thick layer.
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Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as (A) red lines in white developer background. Clean the area of application of the developer with solvent cleaner.Dry Magnetic Particle Inspection
Materials and Equipment Required
Crack Detection Kit
Illustration 26 g03536204 (A) Indications shown by magnetic particle testing. (B) Typical electromagnetic yoke. (C) Dry powder bulb.
Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.
Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.
Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.
Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least 4.5 kg (10 lb).
Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.
All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.Procedure
Insure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.
Apply the magnetic field using the yoke against the faces and inside diameter of each bore.
Simultaneously apply the dry powder using the dry powder blower.
Remove excess powder by lightly blowing away the dry particles.
Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.
Observe particles and note if any clusters of particles appear revealing an indication.
Record the size and shape of any discontinuities or indications found.Wet Magnetic Particle Inspection
Materials and Equipment Required
Crack Detection Kit
UV Lamp Light
Illustration 27 g03536207 (A) Indications shown by magnetic particle testing. (B) Typical electromagnetic yoke. (D) UV lamp used in