Normally, to ensure that a test piece has no cracks, it is necessary to magnetise it in
at least two directions and after each magnetising - and ink application - visually
examine the piece for crack indications.
Since this double process, which would include adjustment of the magnetising
equipment controls in between each magnetising takes time it is obviously
advantageous to have the facility to reduce the time required. The recent
development of the Swinging Field method of multi-directional magnetising will
indicate all defects, regardless of their orientation on the surface, with one
magnetising shot and therefore requires only one inspection. (Please refer to our
paper entitled Faster Magnetic Crack Detection using the Multi-directional Swinging
Field Method).