FAYING SURFACE: The surface of a piece of metal (or a member) in contact with another to which it is or is to be
FBH: Abbreviation for flat bottom hole.
FERRITE BANDING: Parallel bands of free ferrite aligned in the direction of working. Sometimes referred to as
FERROMAGNETIC MATERIAL: Materials that are strongly attracted by a magnetic field. Iron, steel, nickel, and
cobalt are included in this category. Permeability is much greater than one, and is effected by the applied magnetic
field. Such materials exhibit hysteresis behavior.
FERROUS METALS: Containing iron, such as steel, stainless steel and cast iron.
FFD (RT): Film focal distance; distance between film and tube target.
The characteristic of wrought metal that indicates Directional Properties and is revealed by the etching of a
longitudinal section or is manifested by the fibrous or woody appearance of a fracture. It is caused chiefly by the
extension of the constituents of the metal, both metallic and nonmetallic, in the direction of working.
The pattern of preferred orientation of metal crystals after a given deformation process, usually wire-
FIBROUS FRACTURE: A fracture where the surface is characterized by a dull gray or silky appearance. Contrast with
In forgings, a structure revealed as laminations, not necessarily detrimental, on an etched section or as a
ropy appearance on a fracture. It is not to be confused with the silky or ductile fracture of a clean metal.
In wrought iron, a structure consisting of slag fibers embedded in ferrite.
In rolled steel plate stock, a uniform, fine-grained structure on a fractured surface, free of laminations or
shale-type discontinuities. As contrasted with part (1) above, it is virtually synonymous with silky or ductile
FIELD, BIPOLAR (MT): A longitudinal field within a part having two poles.
FIELD, CIRCULAR (MT): The magnetic field surrounding any magnetic conductor or part resulting from the current
being passed through a central conductor or the part.
FIELD COIL (ET): The coil generating the magnetic field that produces eddy currents in the part being tested.
FIELD INDICATOR (MT): A device for indicating the amount of magnetism in a part.
FIELD, LEAKAGE (MT): The field that leaves or enters the surface of a part at a discontinuity or change in section
FIELD, LONGITUDINAL (MT): A field created by a coil shot or cable wrap and in which the flux lines traverse the
part essentially parallel with its longitudinal axis. A localized field, on the surface of a part, traversing from one leg of
a yoke or probe to the other.