MAGNETIC FLUX LEAKAGE TECHNOLOGY IN NDT
Until recently, Eddy Current rotaries were commonly used to find surface detects, usually down to 0.15mm or 0.2mm deep. Now, Alternating Field—or AC Flux Leakage—Testing has extended this capability to finding even smaller defects, as small as 0.1mm deep.
Highly sensitive AC technology is especially well suited to test hot rolled black steel bars and rods that have surface conditions which used to make finding shallow defects very difficult, if not impossible.
- AC technology uses two encircling magnetization yokes and alternating current flows.
- Without contact, these yokes magnetize the test material in the transverse direction.
- The magnetic flux is concentrated on the material’s surface and is particularly sensitive to minor surface defects since the operating probe examines a very small portion of the entire surface at any one moment.