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An Evans balance, also known as a Johnson Matthey magnetic susceptibility balance, is a scientific instrument used to measure the magnetic susceptibility of solids and liquids. [ 1 ] [ 2 ] Magnetic susceptibility quantifies the extent to which a material becomes magnetized in an applied magnetic field .
is the average magnetic path length = 0.94 (constant value) m {\displaystyle m~} is the mass of the sample in kilograms If all conditions are as defined in the standard, the standard deviation of the reproducibility of the values is not greater than 1.5% up to 1.5 T [ clarification needed ] for non-oriented electrical steel and up to 1.7 T for ...
An RFT probe is moved down the inside of a pipe and is able to detect inside and outside defects with approximately equal sensitivity (although it can not discriminate between the two). Although RFT works in nonferromagnetic materials such as copper and brass , its sister technology eddy-current testing is preferred.
In this technique, permeability variations are suppressed by applying a magnetic field. The saturation probes contain conventional eddy current coils and magnets. This inspection is used on partially ferromagnetic materials such as nickel alloys, duplex alloys, and thin-ferromagnetic materials such as ferritic chromium molybdenum stainless steel.
Magnetic flux leakage (TFI or Transverse Field Inspection technology) is a magnetic method of nondestructive testing to detect corrosion and pitting in steel structures, for instance: pipelines and storage tanks. The basic principle is that the magnetic field "leaks" from the steel at areas where there is corrosion or missing metal.
This method of demag was developed to overcome the limitations presented by the AC demag method where part geometry and certain alloys prevented the AC demag method from working. Halfwave DC demagnetizing (HWDC): this process is identical to full-wave DC demagnetization, except the waveform is half-wave.
Hall effect magnetometers (also called tesla meters or gauss meters) use a Hall probe [23] with a Hall element to measure magnetic fields or inspect materials (such as tubing or pipelines) using the principles of magnetic flux leakage. A Hall probe is a device that uses a calibrated Hall effect sensor to directly measure the strength of a ...
The pulse-induction method is based on electromagnetic pulse induction technology to detect rebars. Coils in the probe are periodically charged by current pulses and thus generate a magnetic field. On the surface of any electrically conductive material which is in the magnetic field eddy currents are produced.