p. Perform magnetic crack inspection of crankshaft.
(1) Wet the complete surface with magnetic particle suspension before applying currents.
(2) The following directional magnetizing currents are to be used for crankshaft magnetic inspection or
Direction of Defect
DC or Rectified AC
3600-4000 amp turns
4200-4700 amp turns
Ampere turns in amperage flowing through coil is multiplied by number of turns in
coil; above is for 4 turn coil.
(3) Flow magnetic particle suspension over the part before placing part through coil. Turn current on the coil
and move the coil the full length of the part.
(4) If shaft parts are within 2 or 3 in. of the coil inside diameter ample magnetism will be obtained if 3 shots of
current are passed through coil while it is at each end and the center of part length.
(5) The limits of acceptability, unless otherwise stated, apply only to light slag or oxide stringers usually defined
as inherent inclusions, obvious cracks and circumferential or transverse defects.