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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 .
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.
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.
EN 1369, Founding - Magnetic particle inspection; EN 10228-1, Non-destructive testing of steel forgings - Part 1: Magnetic particle inspection; American Society of Testing and Materials (ASTM) ASTM E1444/E1444M Standard Practice for Magnetic Particle Testing; ASTM A 275/A 275M Test Method for Magnetic Particle Examination of Steel Forgings
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 ...
However, magnetic torque magnetometry doesn't measure magnetism directly as all the previously mentioned methods do. Magnetic torque magnetometry instead measures the torque τ acting on a sample's magnetic moment μ as a result of a uniform magnetic field B, τ = μ × B. A torque is thus a measure of the sample's magnetic or shape anisotropy.
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.
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 ...