- A signal indicating reflected acoustic energy.
- Echoes -
A sound wave that continues to bounce around a room or off other barriers,
or reverberate, until it has lost all its energy.
- Eddy Currents
- Circular induced currents that are generated by an alternating current
in the nearby coil.
- Eddy Current
Inspection - An electromagnetic technique used on
conductive materials for crack detection or the rapid sorting of small components
for either flaws, size variations, or material variation, as well as other
Current Method - An electromagnetic NDT Method based on the process
of inducing electrical currents into a conductive material and observing the
interaction between the currents and the material.
- Eddy Current
Scope - A scope that uses little electrical currents call "eddy currents"
to find defects in different materials.
- Eddy Current
Testing (EC) - An
electromagnetic technique used on conductive materials for crack detection
or the rapid sorting of small components for either flaws, size variations,
or material variation, as well as other applications.
Signal obtained when a surface prove approaches the sample’s edge.
Depth of Penetration -Depth at which eddy current density drops off
to 5% of the surface density.
- Elastic -
Able to return immediately to the original size and shape after being stretched
or squeezed; springy.
- Elastic Constants
- The factors of proportionality that relate elastic displacement of a
material to applied forces.
Deformation - Change of dimensions accompanying stress in the elastic
range, original dimensions being restored upon release of stress.
Limit - The maximum stress to which a material may be subjected with
no permanent deformation after release of the applied load.
- Elastic Modulus
- The ratio of the stress applied to an elastic
body to the change in its shape.
- A design approach used for materials that fracture or behave in a “plastic”
manner, such as lower strength, high-toughness steels.
- Elastic Properties
of Solids - Properties of a solid material defining
how it will react to stress and strain.
- A term that describes how quickly molecules return to their original
- A material with rubber-like properties-that is, quite elastic, returning
to its original size and shape after being deformed.
Motor - A motor that converts electric energy into mechanical energy that
can be used to do work.
Contact - Contact of two conductors allowing current
Current - The movement of electrons between atoms.
Impedance - The total opposition that a circuit presents to an alternating
Noise - Extraneous signals caused by externally radiated signals
or electrical interferences within an ultrasonic instrument. A component of
- A naturally occurring force that exists all around us.
- Pertaining to combined electrical and chemical action. Deterioration (corrosion)
of a metal occurs when an electrical current flows between cathodic and anodic
areas on metal surfaces.
Corrosion - Corrosion which occurs when current flows between cathodic
and anodic areas on metallic surfaces.
- An electrical conductor, usually of metal or graphite, that leads current
into or out of a solution (electrolyte).
- A material, usually a liquid or paste, that will conduct an electric current.
Acoustic Transducer - A device using the magneto effect to generate
and receive acoustic signals for ultrasonic nondestructive tests.
- Wrapping a wire into a coil creates an electromagnet, which behaves
just like a regular permanent bar magnet when the current is flowing.
Acoustic Transducers (EMATS) - A scanning device
which transmits and receives ultrasonic waves.
Field - A field that is created when energy from a power source such as
a battery is applied to a circuit, making the electrons flow through a conductor,
a new type of field is developed around the wire.
Induction - A process by which electrical current is induced in an electrical
conductor by a changing magnetic field that acts upon the conductor.
Radiation - Energy in a wave form that possesses both electrical and magnetic
radiates in the form of a wave which can accelerate charged particles. Electromagnetic
radiation can travel through a vacuum and its energy varies greatly; radio
waves have the longest wavelengths and the lowest frequency and energy, while
X-rays and gamma rays have the shortest wavelengths and highest frequencies
Spectrum - The entire range of wavelengths or frequencies
of electromagnetic radiation extending from gamma rays to the longest radio
Testing - A nondestructive way to test materials
by using electromagnetic energy.
- The production of a magnetic field by current flowing in a conductor.
- An iron bar placed through the center of the coiled wire would become
a temporary magnet, as long as the electric current is flowing through the
Force - The work or energy which causes the flow of an electric current.
Expressed as volts. It should be noted that the term "force" is
a misnomer. However, the term is so well established that its use continues
in spite of its being incorrect.
Force - A force that causes electrons to move in
a particular direction.
Volt - An amount of energy equal to the energy gained by one electron
when it is accelerated by one volt,
- A negatively charged particle that is in constant motion and generally
orbits the nucleus of an atom. The electron is the lightest known particle
that possesses a charge.
- A fairly simple device comprised of a metal rod with two thin leaves
attached to one end. If the electroscope is given a negative charge, the metal
leaves will separate from each other. The rate of discharge of the electroscope
is a measure of ions in the air and can be used as a basis of measurement
Field - Electrons are said to have a negative charge, which means that
they seem to be surrounded by a kind of invisible force field. This is called
an electrostatic field.
Generator - This device accelerates electrons to produce high energy radiation.
- Any material composed of only one kind of atom.
Particle - Originally a term applied to any particle that could not
be further subdivided; now applied only to protons, electrons, neutrons, antiparticles
and strange particles, but not to alpha particles and deuterons.
- Ellipse -
When a parabola is closed off by another curved surface an ellipse is
Void Formula - A formula used to calculate the amount
of time it takes for a viscous fluid to fill an elliptical defect in a material.
- In tensile testing, the increase in the gage length, measured after
fracture of the specimen within the gage length, usually expressed as a percentage
of the original gage length.
- EMATs - Electromagnetic
- Reduction in the normal ductility of a metal due to a physical or chemical
- The energy emission rate usually expressed as r/c/hr @ 1ft or mr/mc/hr @
Time - The period of time during which the emulsifier is permitted
to combine with the liquid penetrant. Emulsification action begins when the
emulsifying agents come in contact with the penetrant and ends with the removal
of this agent, by water rinsing.
- An agent, usually in liquid form which, when combined with a liquid penetrant
that is insoluble in water, renders such a penetrant "soluble" thereby
facilitating its removal by a water wash.
Bath - The bath used to soak a part in a penetrate
fluid to test for defects.
Concentration and Contact Time - The time the material
needs to be soaked in and the concentration of penetrate in the bath depends
on the type of penetrate used and the desired results.
- An additive that promotes the formation of a stable
mixture between two liquids like oil and water.
Penetrant - A mixture of water and oil produced by the addition of
a third material, the liquid penetrant emulsifier.
Radiographic - A gelatin and silver bromide crystal mixture coated
onto a transparent film base.
- The process of sealing radioactive materials to prevent contamination.
Effect - Signal obtained when an internal or encircling probe approaches
the end of a tube or rod (Similar to edge effect).
- A structure in which the grains have approximately the same dimensions in
- The amount of wasted, irregular material (usually snipped or cut off) as
part of the stamping or deep drawing process.
- Destruction of metals or other materials by the abrasive action of moving
fluids, usually accelerated by the presence of solid particles of matter in
suspension. When corrosion occurs simultaneously, the term erosion-corrosion
is often used.
- Error Analysis
- The process used to evaluate the total error throughout
an experiment. This can be due to bias error, precision error as well as others.
Dose - The amount of radiation needed, when applied
to the skin, to make it turn temporarily red.
- A chemical used to etch a metal to reveal the
cracks - Shallow cracks in hardened steel, containing high residual
surface stresses, produced on etching in an embrittling acid.
- Subjecting the surface of a metal to preferential chemical or electrolytic
attack in order to reveal structural details.
The composition in a binary alloy system which melts at minimum temperature.
More than one eutectic composition may occur in a given alloy system.
- The process of deciding the severity of a condition after an indication
has been interpreted. Evaluation determines if the test object should be rejected,
repaired or accepted. See indication and interpretation.
Wave - A disappearing wave.
- A type of corrsion that progresses approximately parallel to the outer surface
of the metal, causing layers of the metal to be elevated by the formation
of corrosion product.
Sweep - A short duration horizontal sweep positioned to provide close
examination of a particular signal.
- The time which radiation is being exposed to
Film - Radiation intensity multiplied by time.
Vaults and Cabinets -
Exposure vaults and cabinets are areas that allow personnel to work safely
in the vicinity while exposures are taking place
Discontinuities - Surface irregularities which cause density variations
on a radiograph. These are observable with the naked eye.