Hall element differential array based ferromagnetic construction member surface crack detector

Abstract

The invention relates to a Hall element differential array based ferromagnetic construction member surface crack detector, comprising a differential array type flux leakage probe, a displacement detecting unit, a signal conditioning circuit and a data acquisition unit; wherein Hall sensors arranged on one surface of a probe circuit board are arranged in a regular array, the Hall sensor group of the probe is arranged at the upper and lower sides of the circuit board in a differential way, two voltage signals are respectively output to the signal conditioning circuit, so as to form a reflective flux leakage voltage signal, and the voltage signal is input into the data acquisition unit. The invention can conveniently detect the size and position of crack defect and has the advantages of large detection area, fast speed and low defect omission ratio.

Description

technical field [0001] The invention relates to the field of non-destructive testing, in particular to the non-destructive testing of defects such as surface cracks, air holes, slag inclusions and stress concentration of ferromagnetic components. Background technique [0002] The existing disclosed ferromagnetic component surface crack detectors have different structures and methods, such as commonly used ultrasonic methods, ray methods, and electromagnetic methods. The ultrasonic method is relatively mature, but it requires high cleanliness on the surface of the workpiece, and it is cumbersome to implement; the ray method is not effective in detecting gradual defects and the radiation pollution is serious; the electromagnetic method includes magnetic particle method, eddy current method, and leakage method. Magnetic method, etc., but magnetic particle method and eddy current method are only suitable for surface or near-surface detection of materials. The degree of automatio...

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Problems solved by technology

However, most of the existing crack detectors based on the magnetic flux leakage method are single probes, with a maximum of three probes, which are expensive and can only perform line scanning on the component surface. The one-time detection area is small, the speed is slow, and the detection is not accurate. Accurate, prone to missing inspections, and cannot provide the data support required for quantitative analysis of defects such as cracks on the surface of components, which seriously hinders the application of magnetic flux leakage in the field of nondestructive testing

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