METHOD FOR MAGNETIC FLAW DETECTION FOR WELD JOINTS USING TWO RIBBONS Russian patent published in 1997 - IPC

FIELD: non-destructive flaw detection. SUBSTANCE: method involves magnetization of tested article together with two magnetic ribbons which differ in their magnetic characteristics, are separated with non-magnetic insertion and arranged on articles surfaces with their non-magnetic substrates turned to one another. Magnetization is done using constant magnetic field. Saturation field of first ribbon which has greater magnetic rigidity is maximal possible. Saturation field of second ribbon is close to start field of first one. Magnetization field is close to saturation field of second ribbon. First ribbon is located closer to article surface. Ribbons which are removed from article are read by means of two transducers in direction which is perpendicular to their length. First transducer is as close to ribbon surface as possible, second transducer has linear response and is spaced from ribbon. EFFECT: increased functional capabilities. 4 dwg