Weld seam testing device guiding system - uses magnetic trace as marking for contactless scanning by magnetic field sensitive scanner

摘要

The testing is carried out by contactless scanning of suitable marks, associated with the welded seams to be tested, the marks being provided on or parallel to the tested seam. A magnetic trace is used as the scanning mark, being provided by magnetisation of the welded material. This trace is scanned by at least one probe, sensitive to magnetic field. Pref. the magnetisation of the welded material is carried out by a magnetic field generating member with poles transverse to the desired magnetic trace, the member being moved over the welded material. The probe may scan the trace along a centre line between induced north and south poles. If two probes are used, they have a constant spacing and scan the trace along their edge lines. Both the probe(s) and the testing device are so arranged that the probe position change causes a corresponding position change of the entire testing device.