System and Method of Measuring Defects in Ferromagnetic Materials

摘要

Defects in ferromagnetic materials are detected and characterized by analyzing the items' magnetic fields to find portions of the magnetic fields that differ in characteristic ways from residual magnetic fields generated by non-defective portions of the items. The portions of the magnetic fields that differ in the characteristic ways correspond to locations of the defects. The residual magnetic fields correspond to portions of the items distant from the defects. The defect characterization may include volume of material lost due to each defect and/or width and/or depth of each defect.

主权项

1. A system for detecting defects in a ferromagnetic material, the system comprising:
a plurality of magnetometers disposed about a surface of the ferromagnetic material, the plurality of magnetometers sensing a magnetic field generated by the ferromagnetic material and generating magnetic field data, based on the sensed magnetic field, wherein each magnetometer of the plurality of magnetometers is fixed in position, relative to the ferromagnetic material; a magnetic field mapper generating data points of a two-dimensional map from the magnetic field data, each data point corresponding to a respective location on the surface of the ferromagnetic material and representing strength of the sensed magnetic field proximate the location; and a pattern matcher that identifies, in the map, a plurality of data points that conform to a predefined spatial pattern of magnetic field strength and outputs a location proximate the surface of the ferromagnetic material that corresponds to the plurality of data points.