Method:

Magnetize the tube under test and locate magnetic flux ‘leakage’ from the surface as a result of a defect.

Application:

Weld (not DSA) testing on-line, and full body testing off-line.  Full body testing only

possible on annealed product.

Product:

All magnetic products, almost no size limits.

Advantages:

High speed testing.  Good sensitivity to both ID and OD defects.  Sensitive to continuous defects.  Non-contact or minimal  contact with product.  InspecTech has refined the technique to test small diameter ERW welds on line.

Disadvantages:

In larger, heavy wall products huge magnetizing forces are created resulting in very

large machines for full body testing.  Interfering signals for ERW welds can limit full

body capability.