Field Intensity
Field intensity comparisons reveal the degree to which a ferrous material concentrates magnetic lines of force. Structural steel permeability determines how much flux will flow through a beam or plate when exposed to an external magnet. The measurement is valid only up to the point of magnetic saturation for the specific alloy grade.
Material Impurity
Carbon content and the manufacturing process influence the magnetic behavior of the metal. Because structural steel permeability is much higher than that of air, it tends to concentrate magnetic flux lines. This can interfere with the operation of nearby magnetic sensors or compasses.
In some cases, the residual magnetism in the steel can create a permanent offset in the measurement.
Calibration Effect
Variations in the alloy composition between different batches can cause the sensor to go out of calibration. Sensors that detect the presence of metal must be tuned to the specific type of steel being used in the construction. The structural steel permeability is measured against a vacuum or a known reference standard.
Technicians use a permeameter to verify the magnetic properties of the material before it is installed.
Magnetic Interference
Large steel structures can distort the earth field and create errors in guidance systems. The structural steel permeability is the main factor used to calculate the required distance between a sensor and the supporting framework.
