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Corrosion Monitoring & Inspection Glossary - F
False Call: An indication from an inspection that is classified as an anomaly where no imperfection, defect, or critical defect actually exists.
Faraday (F): Quantity of electric charge carried by one mole of singly charged atoms, i.e. 96,487 coulombs/mol electrons.
Fatigue: The phenomenon leading to fracture of a material under repeated or fluctuating stresses having a maximum value less than the tensile strength of the material.
Fatigue Cracks: Progressive cracking in the base material, weld, or weld zone that is caused by pressure cycling or oscillatory stresses associated with the operation of a system.
Feature: The presence of any physical object detected by an in-line inspection tool during the performance of an inspection run. Features may be anomalies or indications, pipeline valves and fittings, nearby metallic objects, or other items.
Field signature method (FSM): Corrosion monitoring technique which provides a measure of the thickness of the metal from resistance measurements between sets of pins attached to the surface. A coil surrounding the area produces the magnetic field to induce the current .
Flash Welded: Distinct type of electric resistance weld pipe, made from individually rolled plates formed into cans before being welded.
Flush coupon: Inserted coupon flush with the surface of the pipe or vessel.
Flux: The (scalar) number of flux lines crossing a unit area at right angles to the unit area. See magnetic flux.
Flux Density: (1) A measure of the intensity of magnetization produced by a magnetic field. (2) A vector quantity representing the number of flux lines crossing a unit area at right angles.
Flux Leakage: The flow of flux out of a magnetic material, such as the wall of a pipe, into a medium with lower permeability, such as gas or air.
Fracture Mechanics: A quantitative analysis for evaluating structural reliability in terms of applied stress, crack length, and specimen geometry. For the purpose of this report, the study of the physics of defect initiation and growth in a material.
Fracture Toughness: A measure of the resistance of a material to defect extension, either slow or rapid.
Free Corrosion Potential: The electric potential that exists in the absence of an applied potential with corrosion occurring.
Free Surface: A surface with one side not constrained by adjacent metal, just air.
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