METHOD AND DEVICE FOR MAGNETIC FLAW DETECTION Russian patent published in 2005 - IPC

FIELD: nondestructive check.

SUBSTANCE: method and device can be used for checking ferromagnetic items, for example, steel pipes. Method includes magnetization of part of item, scanning of its surface with magneto-sensitive detectors, generation of information signals, processing of those signals and subsequent determination of item's quality. Signals processing is based upon forming of ancillary signal generated in form of average value signals of two detectors being adjacent of the mentioned. Signal on availability of flaws is also formed which signal is achieved due to subtraction of values of ancillary signal and correction adding from value of signal of basic detector. Device has magnetization system, multiunit converter and maximum selection unit, which has output connected with input of signal processing unit. Detector connected in series with amplifier and collimator forms each measuring unit of converter. Output of detector is connected with inverting input of amplifier. Detectors are grouped to form technological chain. Both inputs of adder are connected with detector, which is disposed close to detector from measuring unit of the adder in technological chain. Outputs of all amplifiers are connected with inputs of maximum value selection unit which has output connected with input of signal processing unit.

EFFECT: increased sensitivity; improved reliability of flaw detection.

5 cl, 6 dwg