METHOD OF DETECTION OF DEFECTS ON SURFACES OF FERROMAGNETIC MATERIALS AND PRODUCTS AND DEVICE FOR ITS IMPLEMENTATION

摘要

FIELD: instrumentation.;SUBSTANCE: invention relates to instrumentation and describes the method and the device for detection of defects on surface of ferromagnetic materials and products. According to the method the tested object is magnetized by one - or two-polar magnetic field impulses, also the acoustic delay of electric signals caused by interaction of magnetic impulses with a defect is performed, and the minimum value of this delay τ_min ≥ T_o where T_o - effective duration of impulse of the magnetic field applied to the studied area of the tested object and is registered by electric signals caused by defect scattering fields. As part of acoustic line of the delay line the tested object itself is used. In the device the reception element is placed at the distance R outside the zone of interaction of the source of pulse magnetic field with defect, the minimum value of which R_min = T_o×C, where T_o - duration of magnetic impulse, C - speed of ultrasonic wave excited by the source of magnetic field in the tested object at interaction of the magnetic field impulse with a defect. Note, that the registering device is configured to the frequency, as a rule, twice exceeding the main frequency of spectrum of the magnetic field impulse sent towards the tested object.;EFFECT: development of devices for detection of defects on surface of ferromagnetic materials and products.;4 cl, 2 dwg